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Pitychoutis, Nikolaos Kokras, and Zeta Papadopoulou-Daifoti Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 2 Sex Differences in Response to Acute and Repeated Stressful Experiences . . . . . . . . . . . . . . . 99 2.1 Sex Differences in Neuroendocrine Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 2.2 Sex Differences in Depressive Symptomatology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 2.3 Sex Differences in Stress Effects on Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 3 Sex Differences in the Effects of Chronic Mild Stress Exposure . . . . . . . . . . . . . . . . . . . . . . . . . 105 3.1 Sex Differences in Behavioural Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 3.2 Sex Differences in Neuroendocrine Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 3.3 Sex Differences in Neurochemical and Neurobiological Alterations . . . . . . . . . . . . . . . 108 3.4 Sex Differences in Immune Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 4 Sex Differences in Sickness Behaviour, a Putative Inflammatory Model of Depression . . 109 5 Sex Differences in a Genetic Model of Depression: Flinders Sensitive Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 6 General Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Abstract Women are more susceptible than men to certain stress-related psychiat- ric disorders, such as depression. Preclinical studies aim to understand these sex differences by studying male and female rats in stress models. In this chapter, we review sex differences in behavioural aspects, as well as neurochemical and neurobiological findings derived from acute, repeated and chronic stress models. In particular, we focus on sex differences in depressive-like symptomatology expressed in the forced swim test, the chronic mild stress (CMS) and the learned helplessness models, the Flinders Sensitive Line rats (FSL), which is a genetic model of depression and in the lipopolysaccharide (LPS)-induced sickness behaviour, a putative inflammatory model of depression. Also, sex differences in stress effects C. Dalla, P.M. Pitychoutis, N. Kokras, and Z. Papadopoulou-Daifoti (*) Department of Pharmacology, Medical School, University of Athens, Mikras Asias 75, Goudi, 11527 Athens, Greece e-mail: zdaifoti@med.uoa.gr J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 97 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010_94, # Springer‐Verlag Berlin Heidelberg 2010, published online 5 October 2010 98 C. Dalla et al. on learning and memory parameters are discussed, because cognitive alterations are often seen in

sex-differentiated psychiatric disorders. The observed behavioural alterations are often linked with abnormalities in the endophenotype, such as in hormonal, neurochemical, immune and neuroplasticity indices. From these data, it is clear that all stress models have strengths and limitations that need to be recognized in order to use them effectively in the investigation of sex differences in affective disorders. Keywords Chronic mild stress
Depression
Flinders sensitive line
Forced swim test
Gender
Immunity
Learned helplessness
Learning
Serotonin
Sex differences
Sickness behaviour
Stress Abbreviations 8-OHDPAT (+)8-Hydroxy-N,N-dipropyl-2-aminotetralin hydrobromide ACTH Adrenocorticotropin hormone AVP Arginine vasopressin CMS Chronic mild stress FSL Flinders sensitive line FST Forced swim test HPA Hypothalamic-pituitary-adrenal HPG Hypothalamus-pituitary-gonadal LPS Lipopolysaccharide LC Locus coeruleus 1 Introduction The organism’s stress response is an evolutionary mechanism of great adaptive value; however, when stress exposure is prolonged and uncontrollable the response may be inadequate and maladaptive for the organism, presumably leading to physical and mental disorders, such as major depression, and anxiety disorders, which are major causes of disability in contemporary western societies (Lupien et al. 2009). Women are more susceptible than men to stress-related psychiatric disorders, such as major depression, generalized anxiety disorder, acute and post- traumatic stress disorder (Holden 2005). It is suggested that because of genetic, hormonal, biochemical and social factors, different responses to stressful life events and different coping strategies used by men versus women ultimately contribute to sex differences in the occurrence of stress-related disorders (Kendler et al. 2001; Maciejewski et al. 2001; Nemeroff et al. 2006; Sherrill et al. 1997). However, the basic neuroendocrine stress response, especially the one associated with acute stress, does not differ substantially between the two sexes (Klein and Corwin 2002). Sex Differences in Response to Stress and Expression 99 Understanding sex differences in the stress response may contribute to the improvement of psychiatric diagnosis and treatment. Animal models have been widely used to study the effects of stress exposure on multiple aspects, such as hormonal, neurochemical, neurobiological and behavioural. Factors that determine the stress response include the type, the duration and the characteristics of the stressors, as well as the strain, the age of the animal and its genetic predisposition (Anisman and Matheson 2005). During the last decades, we have acknowledged the sex of the animal as an important factor that influences the stress response (Palanza 2001; Dalla et al. 2010). Although comparative studies on males and females are still limited, they have been conducted throughout the lifespan of the animal and include different protocols of stressor exposure, as well as genetic manipulations. Additionally, because of the role of stress as a predisposing and precipitating factor in the onset of depression (Anisman and Zacharko 1990; Holsboer 2001) and the marked sex differences in the prevalence of major depression in humans (Marcus et al. 2005), there has been a considerable interest in sex differences in depressive- like symptomatology expressed in several animal stress models. Other behavioural parameters that are studied and are often differentiated between the two sexes are cognitive, anxiety and activity responses. In particular, learning and memory parameters are widely studied in stress paradigms, because cognitive alterations are often seen in sex-differentiated psychiatric disorders, such as depression and post-traumatic stress disorder (Moore 2009; Sotiropoulos et al. 2008). In this chapter, we will review sex differences in the stress response, focusing on beha- vioural and neurochemical changes. 2 Sex Differences in Response to Acute and Repeated Stressful Experiences 2.1 Sex Differences in Neuroendocrine Responses The organism’s acute stress response mainly includes the activation of the locus coeruleus–norepinephrine (LC-NE) system and the hypothalamic-pituitary-adrenal (HPA) axis. The morphology of the LC is sexually dimorphic with females having a greater volume and number of neurons than males (Pinos et al. 2001). Also, its neuronal activity is more responsive to certain stressors in females than in males and this is probably regulated by corticotropin-releasing hormone (CRH) activity (Curtis et al. 2006). On the other hand, HPA axis activation seems to be responsible for the slower response to stress. It is activated within minutes after the stressful stimulus and is initiated by the release of CRH and arginine vasopressin (AVP) by the hypothala- mus (DeBold et al. 1984) and subsequently the release of adrenocorticotropin (ACTH) from the hypophysis. Such a cascade of events results in the release of glucocorticoids, such as corticosterone in rodents, from the adrenal cortex. 100 C. Dalla et al. Under normal conditions, the secreted glucocorticoids inhibit further release of ACTH by feedback inhibition, thus enabling termination of the stress response and a return to homeostasis (Heinrichs and Koob 2004). This feedback is accomplished by the action of glucocorticoids on corticosteroid (GR and MR) receptors that are abundant in the limbic system, especially in the hypothalamus and hippocampus and their activation is sex-dependent (Karandrea et al. 2000, 2002). Sex differences are also evident in other aspects of HPA axis activity; female rats have higher resting levels of corticosterone and display greater diurnal changes in both ACTH and corticosterone than males (Handa et al. 1994; Kitay 1961). Also, in comparison to males, female rats have higher glucocorticoid levels following acute and repeated stress exposure and this seems to be dependent on circulating gonadal hormones (Galea et al. 1997; Seale et al. 2004a,b). Prolonged activation of the HPA axis, as in the case of repeated or chronic stress exposure, can lead to “exhaustion” of the stress response system and halt the return to homeostasis. In this state, stress often has detrimental effects on the integrity and function of the brain. These effects include alterations in the activity of monoamin- ergic systems, in dendritic and synaptic remodelling in the hippocampus and frontal cortex, as well as in levels of adult hippocampal neurogenesis (Galea et al. 1997; McEwen 2002; Shors et al. 2007). In many cases, these changes have been linked to behavioural disturbances, such as depressive-like symptomatology and learning/ memory deficits (Bekris et al. 2005; Bowman 2005; Dalla et al. 2005, 2008a; Kitraki et al. 2004; Shors 2006). 2.2 Sex Differences in Depressive Symptomatology 2.2.1 Swim Stress Exposure: Forced Swim Test As mentioned, the HPA axis is activated in both sexes after acute or short-term stress exposure. For example, when male and female rats are exposed to two sessions of swim stress in two consecutive days (forced swim test; FST), cortico- sterone levels are enhanced in both sexes (Drossopoulou et al. 2004). At a beha- vioural level, both sexes increase their immobility levels during the second FST session, but females exhibit higher levels than males, which is indicative of increased despair and depressive-like symptomatology (Dalla et al. 2008a; Drossopoulou et al. 2004; Pitychoutis et al. 2009b) (Fig. 1). Accordingly, in the open space swimming test, which is a similar animal model to the FST, female rats appear more vulnerable to swim stress than males (Sun and Alkon 2006). During the FST, female rats also exhibit lower levels of head swinging behaviour than males and this has been linked to sex differences in postsynaptic serotonergic 5-HT2A receptor activity (Darmani 1996; Drossopoulou et al. 2004; Matuszewich and Yamamoto 2003). At the neurochemical level, FST induces a decrease in serotonergic activity in the hippocampus and the hypothalamus of female rats, while serotonergic activity is increased in the hypothalamus of males. Moreover, Sex Differences in Response to Stress and Expression 101 Fig. 1 Behaviour of male and female rats during the Forced swim test. Female rats spend more time immobile than male rats during the second session of the Forced swim test (FST), indicating enhanced levels of despair. Also, the duration of climbing, which represents an effort to escape from the cylinder, is higher in males than in females (* = p < 0.05) (Dalla et al. 2008a; Drossopoulou et al. 2004) hypothalamic serotonin 5-HT1A mRNA levels are decreased in female rats; while hippocampal 5-HT1A mRNA levels are increased in males (Drossopoulou et al. 2004). Dopaminergic activity is also increased in the hippocampus and prefrontal cortex of male rats exposed to FST, while there is no effect in females (Dalla et al. 2008a). In both sexes, there is a tendency for enhanced GR mRNA levels 24h after the second swim session (Drossopoulou et al. 2004). However, following longer periods of repeated swim exposure, no alterations in GR or MR mRNA levels are detected in the female hippocampus and hypothalamus, while in males there is a down-regulation of GR mRNA in the hippocampus (Karandrea et al. 2002). Thus, it seems that male rats have an adaptive response to swim stress by exhibiting enhanced corticosterone levels and increases in monoaminergic activity. On the other hand, female rats seem to be more vulnerable to swim stress than males and this is expressed by enhanced levels of despair and decreased serotonergic activity in the hippocampus and hypothalamus. 2.2.2 Shock Exposure: Learned Helplessness Model In response to another kind of stressor (i.e. footshock or tailshock), males and females also exhibit elevated corticosterone levels (Heinsbroek et al. 1991). Numerous studies have shown that most males exposed to this kind of stress that they cannot control, develop helplessness behaviour, because when they are tested on a new task (e.g. avoid the footshock by going through a door-way at a shuttle box twice), they do not escape the stress even if they have the opportunity to do so (Maier 1984). This behaviour has been equated with a sense of “giving up”, experienced by humans with major depression (Miller and Seligman 1975). In male rats, the expression of learned helplessness behaviour in operant-conditioning tasks, is accompanied by a wide range of physiological changes in response to shock, such as enhanced c-fos activity in the hippocampus, amygdala and prefrontal cortex, as well as monoaminergic activation in several brain regions and reduced rates of neurogenesis in the dentate gyrus of the hippocampus (Heinsbroek et al. 1990, 1991; Maier and Watkins 2005; Malberg and Duman 2003; Shors et al. 2007; 102 C. Dalla et al. Trentani et al. 2003). When these stressors are repeated for longer periods and half of the rats can control the stressor by avoiding the shock exposure, corticosterone levels are still enhanced in all groups (i.e. in male rats exposed to controllable or uncontrollable stress) (Shors et al. 1989). However, only male rats, which are exposed to uncontrollable stress, exhibit learned helplessness behaviour, serotoner- gic activation and decreases in hippocampal neurogenesis (Amat et al. 2005; Bland et al. 2006; Heinsbroek et al. 1991; Shors et al. 2007). Regarding females, although corticosterone levels and monoaminergic activity is also enhanced in female rats in response to footshock (Heinsbroek et al. 1991), most female rats do not express helplessness behaviour after acute or repeated uncontroll- able footshock stress exposure (i.e. they learn to escape on the new task), while there is no effect of stress on neurogenesis levels in their hippocampus (Dalla et al. 2008b; Shors et al. 2007). Also, controllability over the stressor influences the degree of monoaminergic activation in a sex-dependent manner. In particular, the activation of noradrenaline and dopamine in the frontal cortex is larger after uncontrollable shock than after controllable shock and these differences are most evident in females. Moreover, uncontrollable shock induces higher serotonin levels in the frontal cortex of both sexes than controllable shock (Heinsbroek et al. 1991). Notably, sex differences in learned helplessness behaviour cannot be attributed to gonadal hormonal differences, because they are not reversed by gonadectomy in adulthood of males or females (Dalla et al. 2008b) (Fig. 2). Sex differences in the learned helplessness model are probably mediated by sex differences in baseline escape behaviour in the operant-conditioning task, as well as in general activity levels. Indeed, unstressed female rats are in general more active and express less freezing behaviour than males (Dalla and Shors 2009; Padilla et al. 2009). Overall, it seems that in this model, sex differences in the phenotype (i.e. behavioural sex differences in learned helplessness behaviour) do not always reflect sex differences in the endophenotype (e.g. corticosterone levels are equally affected in males and females by uncontrollable stress). However, levels of adult neurogen- esis in the hippocampus seem to correlate with helplessness behaviour (Malberg and Duman 2003; Shors et al. 2007). Finally, controllability over the stressor seems to be an important factor, which determines the stress response in both sexes. 2.3 Sex Differences in Stress Effects on Learning 2.3.1

Associative Learning Stress effects on different types of learning also differ between male and female rats. Regarding associative learning, exposure to an acute or repeated painful stressful event (i.e. tailshock, footshock or swim stress, but not restraint) greatly enhances learning during eyeblink classical conditioning in male rats, whereas the same stressor impairs learning in females (Shors 2006). Interestingly, ani- mals that are exposed to the same amount of controllable shock do not express any change in this type of learning (Leuner et al. 2004). Corticosterone levels are Sex Differences in Response to Stress and Expression 103 Fig. 2 Males express learned helplessness behaviour whereas females do not. During testing for learned helplessness behaviour, the rats have to cross a shuttle-box twice to escape the footshock. The graph depicts the escape latencies of male and female sham-operated and gonadectomized rats that were previously exposed to 7 sessions of controllable or uncontrollable footshock stress. Male sham- operated and castrated rats from the uncontrollable stress groups, did not learn to escape during testing and thus exhibited learned helplessness behaviour (p > 0.05). On the other hand, female sham-operated and ovariectomized (OVX) rats from the uncontrollable stress groups learned to escape during testing and did not exhibit learned helplessness behaviour (p < 0.001) (Dalla et al. 2008b) 104 C. Dalla et al. enhanced in both sexes in response to the stressor, but adrenalectomy and gonadectomy studies have shown that males require the presence of glucocorti- coids to enhance learning after stress, whereas females require the presence of ovarian hormones in order to impair learning after stress (Beylin and Shors 2003; Wood and Shors 1998). In particular, the impairment of associative learning after stress exposure emerges only in adult females with a mature oestrous cycle and is evident when females start training with eyeblink conditioning in proes- trus when oestrogen levels are high (Shors et al. 1998). Interestingly, the emergence of the stress effects on this type of associative learning in both males and females require an intact hippocampus (Bangasser and Shors 2007). Also, the same acute stressful experience increases the density of dendritic spines in the CA1 area of the male hippocampus and decreases it in the females, suggesting a link between density of spines in the hippocampus and associative learning (Shors et al. 2001, 2004). Notably, masculinized females injected with testosterone on the day of birth, exhibit enhanced learning during eyeblink conditioning and possess more spines in the CA1 area of the hippocampus after acute tailshock exposure (Bangasser and Shors 2008; Dalla et al. 2009). Thus, females appear to be more vulnerable to shock exposure when associative learning and spine density in the hippocampus is evaluated. This is in contrast to the expression of helplessness behaviour that is mainly evident in male rats. The discrepancy between the two types of learning is probably due to inherent differ- ences between the operant conditioning and the classical conditioning tasks. During operant conditioning that is used for assessment of learned helplessness behaviour, the animal must emit a voluntary motor response in order to change the outcome and learn, whereas during classical conditioning, which is indicative of associative learning, the animal emits an obligatory unconditioned response to the uncondi- tioned stimulus, irrespective of volition (Shors 1998). Thus, it is not surprising that males and females respond differently in the two tasks and that sex effects are differently mediated by gonadal hormones. 2.3.2 Spatial Learning In contrast to classical conditioning tasks, opposite effects of stress on performance of male and female rats in spatial learning and memory tasks have been repeatedly reported (Bowman 2005; Bowman et al. 2003). Following acute restraint stress, spatial memory in a Y-maze is impaired in males and is facilitated in females, irrespective of the oestrous cycle, while corticosterone levels are enhanced in both sexes (Conrad et al. 2004). Acute restraint stress has also been shown to enhance serotonergic activity in the basolateral amygdala of both sexes, but female rats show a greater response than males. Moreover, dopaminergic activity is increased in female rats, but not in males (Mitsushima et al. 2006). In the hippocampus, acute restraint stress significantly decreases brain-derived neurotrophic factor (BDNF) in both males and females in the CA3 area. In the dentate gyrus of the hippocampus, stress increases BDNF levels only in estradiol-treated ovariectomized rats, while it Sex Differences in Response to Stress and Expression 105 decreases its levels in oestrogen-deprived rats (Franklin and Perrot-Sinal 2006). This finding can probably be linked with reduced levels of adult neurogenesis in the female hippocampus when oestrogen levels are low (Tanapat et al. 1999). After one week of repeated restraint stress exposure, male rats are impaired in the object recognition test, while females exhibit enhanced performance during spatial memory tasks. These behavioural changes are accompanied by increased noradrenergic activity in the hippocampus and amygdala of females and decreased activity in males (Bowman et al. 2009). In the medial prefrontal cortex, the same protocol decreases the number and length of the apical neuronal dendritic branches of males, whereas in females, the same stress exposure increases apical dendritic length and this is prevented by ovariectomy (Garrett and Wellman 2009). The detrimental effect of stress on the Morris water maze task is most evident in male rats exposed to longer periods of repeated restraint stress (21 days), while females exhibit improved memory scores (Bowman et al. 2003; Kitraki et al. 2004). Also, behavioural changes are accompanied by a decrease in GR receptor immu- noreactivity in the male and an increase in the female hippocampus (Kitraki et al. 2004). The same stress protocol also decreases dopaminergic activity in the frontal cortex and amygdala of males but not females; whereas, in the hippocampus, stress increases levels of serotonin and noradrenaline in females, but not in males. These effects seem to depend on both organizational and activational effects of gonadal hormones (Luine 2002). Twenty one days of repeated restraint stress also induces apical dendritic atrophy of the CA3 pyramidal neurons in the male hippocampus, while this effect is not evident in females (Galea et al. 1997). However, spinophilin levels, which are indicative of new spine formation, are elevated in the male, but not female hippocampus following repeated restraint stress exposure (Khurana and Devaud 2007). Thus, it seems that, in contrast to swim or shock stress exposure, males are more vulnerable to restraint stress than females, because they exhibit learning and memory deficits in spatial tasks, as well as decreases in monoamine levels and activity and decreases in certain neuroplasticity indices. On the other hand, females seem to adapt better to this type of stress exposure. 3 Sex Differences in the Effects of Chronic Mild Stress Exposure Chronic mild stress (CMS) was developed in the late 1980s and is one of the most extensively investigated animal models of depression to-date. CMS’s advantage over other models of depression lies on the fact that it employs relatively realistic inducing conditions (construct validity), simulates anhedonia which is a core symptom of major depression (face validity), and responds appropriately to antidepressant drugs (predictive validity) (Willner 1997, 2005; Willner et al. 1987). The CMS procedure involves continuous exposure to a variety of low- grade stressors, such as periods of food and water deprivation, small temperature 106 C. Dalla et al. Table 1 Example of a weekly CMS protocol Monday 10:00 h Cage cleaning followed by no stress Monday 20:00 h Food and water deprivation for 14 h Tuesday 10:00 h Sucrose test, followed by food or water deprivation for 10 h Tuesday 20:00 h Paired housing for 14 h Wednesday 10:00 h Lights switched on and off every 2 h for 10 h Wednesday 20:00 h Soiled cage (250 ml of water was poured into the sawdust bedding) for 14 h Thursday 10:00 h Cage cleaning, followed by water deprivation for 10 h Thursday 20:00 h Paired housing for 14 h Friday 10:00 h Stroboscopic illumination in darkness for 10 h Friday 20:00 h Food deprivation for 14 h Saturday 10:00 h Tilting of the cages backwards (45 degrees) for 10 h Saturday 20:00 h Cages were put back in straight position/followed by no stress Sunday 10:00 h Stroboscopic illumination in darkness for 10 h Sunday 20:00 h Soiled cage (250 ml of water was poured into the sawdust bedding) for 14 h reductions, changes of cage mates, and other similar mild manipulations (Table 1). Animals subjected to a battery of mild stressors for a period of several weeks develop a wide spectrum of behavioural, biochemical and physiological altera- tions, which can be effectively reversed upon chronic antidepressant treatment (Willner 1997, 2005). Exposure to a CMS regime ultimately leads to the induction of anhedonia (i.e. loss of pleasure derived from normally rewarding activities), which accounts for the impairment of rodents’ preference for a palatable sucrose (or saccharin) solution. Beyond anhedonia, this model simulates other symptoms of depression as well, such as decreased sexual behaviour and self-care, changes in sleep architecture and locomotor activity, as well as cardiovascular and immune alterations (Willner 1997, 2005). However, there have been some replication problems in CMS among laboratories (Willner 2005), mainly due to the failure of eliciting a significant decrease in sucrose consumption. This has been partly attributed to individual differences regarding rats’ hedonic status quo (Duncko et al. 2003), as well as to differences between different strains of rats (Bekris et al. 2005; Konkle et al. 2003). Thus, it can be suggested that, besides sucrose consumption, we may be in need of more robust and extensive outputs to evaluate how CMS exerts its “depressogenic” influences on rats of both sexes. It is worth noting that the induction of anhedonia after CMS exposure has also been validated with the intracranial self stimulation paradigm, but inter-individual differences have also been reported (Nielsen et al. 2000). Moreover, the duration of stress application (e.g. 3 versus 7 weeks) and the stress regime itself (i.e. the cyclicity of the stressors) may also explain some of the discrepancies between different studies. 3.1 Sex Differences in Behavioural Responses Sex differences in reward sensitivity are revealed when the CMS model of depres- sion is applied to male and female rats. Rewarding reactivity to sucrose is impaired in both sexes (Duncko et al. 2001), but this phenomenon appears to be more robust Sex Differences in Response to Stress and Expression 107 Fig. 3 Sucrose intake in male and female rats during Chronic mild stress. Male rats exposed to Chronic mild stress (CMS) consume a lower amount of a sucrose solution (1%) than control rats, during all weeks of CMS exposure. This effect is evident in female rats only during the first and fourth week of CMS exposure (* = p < 0.05) (Dalla et al. 2005) in male compared to female CMS-exposed rats (Dalla et al. 2005, 2008a; Grippo et al. 2005; Kamper et al. 2009) (Fig. 3). As a matter of fact, it has been suggested that sucrose intake might not be an appropriate behavioural index for female rats, because unstressed females tend to drink more sucrose than males and show a more erratic increase in their consumption (Dalla et al. 2005). Interestingly, it has been shown that pair- or group- housing conditions may diminish the effects of CMS on body weight and sucrose consumption, in comparison to single-housed female rats (Baker and Bielajew 2007). On the other hand, another study that measured sucrose intake during 24 h periods has revealed a gradual reduction of sucrose consumption in female, but not in male CMS-treated rats (Konkle et al. 2003). However, no changes in thresholds for brain stimulation reward were observed in two strains of female rats (Baker et al. 2006). As far as other behavioural measurements are concerned, female rats display less exploratory behaviour in a novel open field environment following three weeks of CMS application (Dalla et al. 2005). In another study, total activity in the open field test did not differ between stressed male and female rats, but CMS-exposed male rats exhibited enhanced locomotor activity during the first minute of the session, suggesting increased anxiety (Duncko et al. 2001). 3.2 Sex Differences in Neuroendocrine Responses CMS application has been reported to dysregulate both the HPA and the hypothal- amus-pituitary-gonadal (HPG) axes. For example, CMS induces severe disruptions of normal oestrous cyclicity. These alterations typically involve desynchronization of oestrous cycling in CMS-treated female

rats that is either expressed by staying in one phase of the cycle or lengthening of the oestrous cycle (Baker et al. 2006; Dalla et al. 2005; Grippo et al. 2005; Konkle et al. 2003). However, in most cases when the stressful manipulations cease, the normal cyclicity is restored (Baker et al. 2006). 108 C. Dalla et al. Impaired function of the HPA axis has repeatedly been noticed in patients with major depression (Holsboer 2000). As such, following, 3–4 weeks of CMS exposure both male and female rats displayed a tendency towards higher basal corticosterone levels (Duncko et al. 2001; Grippo et al. 2005). However, follow- ing 6 weeks of CMS exposure, a sex-specific elevation of corticosterone concen- trations was observed only in female rats, suggesting that females are more vulnerable in the CMS model of depression than males (Dalla et al. 2005). Overall, it seems that there is an important time factor that differentiates cortico- steroid responses between the two sexes upon chronic stress application. 3.3 Sex Differences in Neurochemical and Neurobiological Alterations CMS exposure in male rats induces alterations in noradrenergic, dopaminergic and serotonergic status. In our initial studies in male rats, we observed an increase in dopaminergic and a decrease in serotonergic activity in the prefrontal cortex in two strains of male rats (Sprague-Dawley and Wistar rats) exposed to 7 weeks of CMS (Bekris et al. 2005). In the same study, we found a decrease in striatal dopaminergic activity and an increase in serotonergic activity in the hippocampus of male rats. All these effects were reversed by chronic imipramine treatment (Bekris et al. 2005). In further comparative studies between male and female rats, we used a milder CMS protocol, which did not induce neurochemical alterations in male rats, but resulted in a decrease in hippocampal serotonergic activity and prefrontocortical dopami- nergic activity in females (Dalla et al. 2005, 2008a). Accordingly, exposure to CMS induces a wide spectrum of relevant neurobiologi- cal alterations in specific brain regions implicated in the pathophysiology of major depression. For instance, it has been reported that hippocampal 5HT1A receptors are increased by CMS in male rats (Papp et al. 1994). Four weeks of CMS exposure attenuates ACTH responses following systemic administration of a selective 5-HT1A receptor agonist [(+)8-hydroxy-N,N-dipropyl-2-aminotetralin hydrobromide; 8-OH- DPAT] in both male and female rats (Grippo et al. 2005). These results were extrapolated as being indicative of CMS-driven alterations in 5-HT1A receptor function in specific subpopulations of neurons in the central nervous system (Grippo et al. 2005). Also, it has been shown that CMS exposure is associated with a sex- specific enhancement of CRH mRNA levels in the hypothalamus of male rats (Duncko et al. 2001). Additionally, tyrosine hydroxylase mRNA levels in the LC were significantly decreased in response to CMS in both sexes, indicating an impairment of the central noradrenergic function (Duncko et al. 2001). Thus, male and female rats are differentially affected by CMS application depending on the neurobiological indices that are measured. In some studies, females appear to be more vulnerable (e.g. serotonergic activity) while in other studies the two sexes are equally affected. Sex Differences in Response to Stress and Expression 109 3.4 Sex Differences in Immune Parameters CMS has long been associated with alterations in central and peripheral monoam- inergic systems, as well as immunoreactivity (Willner 2005). CMS application has been shown to induce robust changes in thyroid hormone levels and reduction of the thymus weight in male rats (Kioukia-Fougia et al. 2002; Kioukia et al. 2000). In a recent study, we reported for the first time that both chronic clomipramine treatment and CMS application, exerted sexually dimorphic effects on cellular immunoreac- tivity [natural killer (NK) and lymphokine-activated killer (LAK) cell cytotoxicity and interleukin-2-induced T-cell proliferation], with female rats presenting a rela- tively immunosuppressed phenotype compared to males (Pitychoutis et al. 2009a). In addition, CMS and chronic clomipramine treatment induced sex-dependent alterations in the monoamine profile of the thymus. Thymic DA levels were augmented only in CMS-treated female rats with this increase being partially reversed by chronic clomipramine treatment. Further, while CMS application did not alter 5-HT and NA concentrations in either sex, chronic antidepressant treat- ment elevated thymic NA levels only in male rats, irrespective of stress application (Pitychoutis et al. 2009a). Intriguingly, clomipramine treatment rendered thymic 5- HT a positive modulator of LAK cytotoxicity; thymic monoamine alterations being associated with functional measures of cellular immunity are suggestive of a thymus-dependent route by which antidepressants could affect cell-mediated immunity (Pitychoutis et al. 2009a; Pitychoutis et al. 2010). 4 Sex Differences in Sickness Behaviour, a Putative Inflammatory Model of Depression Data accumulated largely during the last two decades advocate the innate immune response as a mechanism that may be implicated in the pathophysiology of major depression, mainly due to the documented alterations in the ability of immune cells to secrete proinflammatory cytokines (Dantzer et al. 2008). Challenging the innate immune machinery with the proinflammatory agent lipopolysaccharide (LPS) induces a mild state of nosothymia, termed as sickness behaviour. Sickness beha- viour is conceptualized through numerous depressive-like behavioural and physio- logical manifestations, most of which overlap with the clinical symptoms of depression (i.e. anhedonia, depression in motor/exploratory activity and a reduction in food intake, activation of the HPA axis, as well as alterations in central and peripheral monoamine utilization) (Dantzer et al. 2008; Zampeli et al. 2009). Behavioural responses in LPS/cytokine-induced sickness have been studied in both male and female rats in only a few studies. Female rats exhibit greater sensitivity than males to LPS and/or cytokine administration in several aspects of behaviour, including sexual activity and sucrose reward (Avitsur and Yirmiya 1999; Merali et al. 2003). However, in vitro experiments have shown that 110 C. Dalla et al. LPS-challenged macrophages derived from male mice produced higher levels of inflammatory cytokines than similarly treated female-derived cells, suggesting that males may be more susceptible to bacterial sepsis than females (Marriott et al. 2006). Furthermore, female rats develop behavioural tolerance to repeated LPS administration more quickly than males and this phenomenon was found to be oestrous cycle-dependent (Engeland et al. 2006). Traditional measures of sickness (i.e. impairment of social exploration of a juvenile conspecific and weight loss) have been shown to be equally affected in male and female rats, except for anorexia (lack of appetite for food) establishment where males appeared to be more vulnerable (Pitychoutis et al. 2009b). Sickness establishment also alters the way the two sexes react upon stress exposure. In particular, LPS administration (100 mg/kg) induced a beneficial female-specific enhancement of coping ability in the stressful FST, as evidenced by the increased swimming durations achieved during the second swim session induced (Pitychoutis et al. 2009b). However, it has been shown that higher doses of LPS (e.g. 2 mg/kg) reliably induced an increase in floating time in rats of both sexes, at 24 h post-injection (Tonelli et al. 2008). Finally, anhedonia, which is a core symptom of depression, was equally established in both sexes at 24 h post-LPS administration, with this effect being reversed within the following day (Pitychoutis et al. 2009b) (Fig. 4). Ex vivo neurochemical analysis at 2 h post-LPS administration, when many symptoms of sickness reach a plateau, indicated that central serotonergic activity in female rats is enhanced in all limbic sites examined (i.e. hypothalamus, hippocam- pus, prefrontal cortex, hippocampus, amygdala and striatum). On the other hand, serotonergic status in male rats was only modestly altered (Pitychoutis et al. 2009b). Dopaminergic indices were primarily affected in female rats, especially in the striatum, while there were no apparent alterations in males following LPS administration. In addition, neuroendocrine corticosteroid responses further confirm that females are more vulnerable to LPS sensitization compared to males Fig. 4 Sucrose intake after Lipopolysaccharide (LPS) administration. Anhedonia was established equally in rats of both sexes at 24 h post-LPS (100 mg/kg, ip) administration, as evidenced by the relative consumption of a sucrose solution (1%). This effect was reversed within the following day (* = p < 0.05) (Pitychoutis et al. 2009b) Sex Differences in Response to Stress and Expression 111 (Frederic et al. 1993; Pitychoutis et al. 2009b; Spinedi et al. 1994; Tonelli et al. 2008). The apparent sex differences underlying the neurochemical and behavioural profile of sickness behaviour point to the important role of the immune system activation in the pathophysiology of depression. Taking into account the higher prevalence of affective disorders in females, a focus on the basic science of sex differences that underlie sickness behaviour is useful in delineating the neuroim- munological substrate for the appearance, course and outcome of these conditions (Pitychoutis and Papadopoulou-Daifoti 2010). 5 Sex Differences in a Genetic Model of Depression: Flinders Sensitive Line Current evidence points towards a gene-environment interaction in the ability to cope with stress and with the predisposition to stress-related disorders, such as depression (Cryan and Slattery 2007). In agreement with this, many laboratories study genetic models of depression, such as the Flinders Sensitive Line (FSL) of rats. These rats have been created by selectively breeding Sprague-Dawley rats for their hyper-sensitivity to cholinergic agonists; a characteristic that has also been observed in depressed humans (Overstreet et al. 2005). FSL rats present a number of behavioural similarities to depressed individuals, such as reduced general activity, disturbed appetite, REM-sleep abnormalities and anhedonia (Yadid et al. 2000). Also, FSL rats display a clear depressive-like behavioural profile, particularly showing increased immobility, already observed from the first swim session of the FST paradigm. Chronic treatment with different antidepres- sant agents successfully reverses the depressive-like behaviour of male FSL rats (Kokras et al. 2009a; Overstreet et al. 2005). Regarding females, we have found that they do not exhibit enhanced immobility levels, but they show decreased latency to become immobile, in comparison to Sprague-Dawley controls. Inter- estingly, sex differences in FST performance are alleviated following treatment with the tri-cyclic antidepressant, clomipramine (Kokras et al. 2009a) (Fig. 5). Sex differences are also present in the frequency of head swinging behaviour, with female FSL rats exhibiting lower levels than males, as do Wistar rats (Drossopoulou et al. 2004). However, antidepressant treatment does not affect head swinging behaviour and sex differences are still apparent after treatment (Kokras et al. 2009a). Male FSL rats exhibit several neurochemical abnormalities, including seroto- nergic alterations, increased levels of catecholamines and their metabolites, and impaired communication between serotonergic and dopaminergic systems in limbic brain regions (Kokras et al. 2009a; Yadid et al. 2000). In male FSL rats at baseline, serotonergic activity, as indicated by serotonin turnover, is lower in limbic regions, compared to Sprague-Dawley controls, while it is modestly increased after chronic 112 C. Dalla et al. Fig. 5 Behaviour of male and female Flinder rats during Forced swim test. Male Flinders Sensitive Line rats (FSL) exhibited increased immobility duration during one session of FST, in comparison to Sprague-Dawely (SD) rats, which serve as controls. Female FSL rats exhibited reduced latency to become immobile during one session of FST, in comparison to SD rats, which serve as controls. Chronic clomipramine treatment reversed the immobility duration and latency in both sexes (*,# = p < 0.05) (Kokras et al. 2009a) treatment with a tri-cyclic antidepressant (Kokras et al. 2009a). Interestingly, this is not the case for female FSL rats, which do not differ in serotonergic activity from their control Sprague-Dawley rats. However, clomipramine treatment results in a marked increase in serotonergic activity of female FSL rats in all brain regions tested (Kokras et al. 2009a). Also, clomipramine treatment increases cortical glutamate levels in both sexes and hippocampal glutamate only in female FSL rats (Kokras et al. 2009b). These findings indicate that antidepressant treatment may alleviate sex differences in the phenotype (i.e. converging effects on behaviour during FST) while maintaining or intensifying sex differences in the endopheno- type (i.e. serotonergic activity). Sex Differences in Response to Stress and Expression 113 6 General Conclusions Overall, it seems that the type and the duration of stressor, as well as the behavioural parameters that we measure, influence the appearance and direction of sex differences in stress response. Depressive-like symptomatology is also expressed differently between the two sexes depending on the model. For example, although female rats appear to be more vulnerable in the FST and CMSmodels and following LPS adminis- tration, they do not exhibit learned helplessness behaviour in response to footshock. In most cases, behavioural alterations can be

linked with abnormalities in the endophenotype, such as in hormonal, neurochemical, immune and neuroplasticity indices. In particular, the HPA axis is activated in both sexes after stress exposure, but some components are differentiated between the two sexes pointing to its importance in the emergence of stress-related disorders, such as depression. Also, monoamines are generally activated after stress exposure, but in some cases, especially in females, we observe decreases in monoaminergic activity in response to stress, which may be linked with the higher incidence of depression in women (Deecher et al. 2008). Moreover, sex differences are mediated in a complex way by the effects of gonadal hormones during development of the brain (organizational effects), during puberty and in adulthood (activational effects). Finally, it can be hypothesized that certain stress models can lead to decreases in serotonergic activity in the hippocampus of female rats, which in turn can be linked with decreased neuroplasticity associated with cognitive impairment and depressive- like symptomatology.However,more studies focusing on animalmodels validated for females are needed in order to evaluate this hypothesis. Overall, it is clear that all the stress models have strengths and limitations that need to be recognized in order to use them effectively in the investigation of affective disorders. Limiting research on depression to male animals, may lead to inaccurate findings or hide important results that apply only to women. Also it is possible that sex hormone’s actions on the brain from “womb to tomb” may affect the brain in a sexually dimorphic manner. This could lead to increased vulnerability to stressors, different coping strategies and differentiated responsivity to antidepressants in women. Acknowledgements Dr. Christina Dalla was a Marie Curie International Fellow, funded from the European Commission within the 6th European Community Framework Programme. This work has been supported by the Greek General Secretariat of Research and Technology and by Research Grants from the Special Account for Research Grants of the University of Athens (Greece). References Amat J, Baratta MV, Paul E, Bland ST, Watkins LR, Maier SF (2005) Medial prefrontal cortex determines how stressor controllability affects behavior and dorsal raphe nucleus. Nat Neurosci 8:365–371 Anisman H, Matheson K (2005) Stress, depression, and anhedonia: caveats concerning animal models. Neurosci Biobehav Rev 29:525–546 114 C. Dalla et al. Anisman H, Zacharko RM (1990) Multiple neurochemical and behavioral consequences of stressors: implications for depression. 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It is known that genetic factors contribute to these sex dimorphisms, but the individual genes have rarely been identified. The catechol-O-methyltransferase (COMT) gene, which encodes an enzyme that metabolises catechol compounds, including dopamine, is a leading candidate in this regard. COMT’s enzyme activity, and the neurochemistry and behaviour of COMT knockout mice are both markedly sexually dimorphic. Fur- thermore, genetic associations between COMT and psychiatric phenotypes fre- quently show differences between men and women. Although many of these differences are unconfirmed or minor, some appear to be of reasonable robustness and magnitude and are reviewed in this chapter. Sexually dimorphic effects of COMT are usually attributed to transcriptional regulation by oestrogens; however, a careful examination of the literature suggests that additional mechanisms are likely to be at least as important. Here, we review the evidence for a sexually dimorphic influence of COMT upon psychiatric phenotypes and brain function, and discuss potential mechanisms by which this may occur. We conclude that despite the evidence being incomplete, there are accumulating and in places compelling data showing that COMT has markedly sexually dimorphic effects on brain function and its dysfunction in psychiatric disorders. Although oestrogenic regulation of COMT is probably partially responsible for these sex differences, other mechanisms are likely also involved. Since sex differences in the genetic architecture of brain function and psychiatric disorders are the rule not the exception, we anticipate that additional evidence will emerge for sexual dimorphisms, not only in COMT but also in many other autosomal genes. E.M. Tunbridge (*) and P.J. Harrison Department of Psychiatry, University of Oxford, Neurosciences Building, Warneford Hospital, Oxford, OX3 7JX, UK e-mail: elizabeth.tunbridge@psych.ox.ac.uk J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 119 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010_97, # Springer‐Verlag Berlin Heidelberg 2010, published online 5 October 2010 120 E.M. Tunbridge and P.J. Harrison Keywords Dopamine
Gender
Genotype
Polymorphism
Sexual dimorphism As the contributions to this volume make clear, sex is a key factor in neuroscience (Cahill 2006) and psychiatry (Cosgrove et al. 2007). Many aspects of brain function and structure vary between men and women (Gur et al. 1995; Murphy et al. 1996; De Courten-Myers 1999; De Bellis et al. 2001; Goldstein et al. 2001; Preece and Cairns 2003; De Vries 2004), and most psychiatric disorders show sex differences in one or more variables including incidence, age at onset, clinical features, and outcome (Lensi et al. 1996; Tamminga 1997; Piccinelli and Wilkinson 2000; Aleman et al. 2003; Baron-Cohen et al. 2005). These dimorphisms are usually assumed to result from the effects of sex hormones (Collaer and Hines 1995; Rubinow and Schmidt 1996; Seeman 1997; Kelly et al. 1999), as well as to the actions of genes located on the sex chromosomes (Vawter et al. 2004; Cutter et al. 2006; Davies and Wilkinson 2006). However, sex differences in epigenetic mechanisms, such as DNA methylation and chromatin modifications, relevant to brain function may also play a major role (Kaminsky et al. 2006). Furthermore, there is also evidence that autosomal genes contribute to sex differences in the genetic predisposition to psychiatric phenotypes. For example, sex differences have been found in the chromosomal loci implicated in the vulnerability to major depression (Holmans et al. 2004; Nash et al. 2004), neuroticism (Fullerton et al. 2003), obsessive–compulsive disorder ([OCD]; Nestadt et al. 2000), and autism (Stone et al. 2004). These differences occur in addition to sex differences in the heritability estimates for certain disorders; for example, major depression is estimated to be more heritable in women than men (Kendler et al. 2006). Taken together, these indications that there are differences in the genetic factors con- tributing to psychiatric phenotypes in men and women are consistent with the fact – not always appreciated – that the genetic basis of many, perhaps most, human traits is sexually dimorphic (Weiss et al. 2006). Although, as described above, a diverse set of evidence demonstrates that there are sex differences in the genetic modulation of normal brain function and psychi- atric disorders, few candidate genes for mediating these sex differences have been described. Here, we outline evidence that COMT is one such gene and consider the mechanisms by which its sexually dimorphic effects on brain function may be mediated. This chapter is an updated version of, and revised from, a recent review (Harrison and Tunbridge 2008). 1 Catechol-O-methyltransferase The neurobiology and pharmacology of COMT have been reviewed in detail elsewhere (Weinberger et al. 2001; Tunbridge et al. 2006a; Mannisto and Kaakkola 1999); however, a brief introduction is given below. The COMT enzyme metabo- lises catechol-containing compounds, including dopamine and noradrenaline and, Importance of the COMT Gene for Sex Differences in Brain Function and Predisposition 121 notably with respect to sex differences, catechol oestrogens. The COMT gene exists in at least two protein isoforms produced from alternate start codons: membrane- bound COMT (MB-COMT) and soluble COMT (S-COMT), which differ in their capacity and affinity for different catechols. In contrast to the dominance of S-COMT in most peripheral tissues, MB-COMT is the most abundant isoform in brain, consistent with its high affinity for the catecholamine neurotransmitters. The relevance for COMT in regulating brain function and risk for psychiatric disorders arises primarily from its key role in regulating cortical dopamine (Tunbridge et al. 2004a; Yavich et al. 2007). However, as outlined below, COMT’s role in metabo- lising catechol oestrogens, a function which is generally overlooked from a neuro- biological perspective, may be important for mediating some of its sexually dimorphic effects. The COMT gene is located on chromosome 22q11. It contains several single nucleotide polymorphisms (SNPs) of known or suspected functional significance. The best studied of these is rs4680, a 472 G/A substitution at codon 158 in MB- COMT (codon 108 in S-COMT) that encodes either the ancestral valine (Val158) or methionine (Met158), which we refer to as Val158Met. The Val158Met SNP directly affects the thermal stability of COMT; therefore, at 37C the Val158 form is more stable, and thus more active, than the Met158 form. In human prefrontal cortex, this substitution results in an approximately 40% reduction in Met/Met homozygotes, compared with Val/Val homozygotes, with heterozygotes

showing intermediate COMT enzyme activity (Chen et al. 2004). Earlier studies reported even greater differences in erythrocyte COMT activity between Val/Val and Met/Met carriers (Lachman et al. 1996), although this might, in part, result from methodological differences between the studies. Nevertheless, the Val158Met-encoded enzyme activity differences, coupled with the importance of COMT for regulating cortical dopamine levels, suggest that cortical dopamine signalling is likely to be enhanced in Met158- compared to Val158-carrying individuals. Following the landmark study of Egan et al. (2001), a range of studies have shown that the Val158Met allele has a small but significant impact on working memory, attention and executive perfor- mance, and prefrontal efficiency, with Met158-carrying individuals performing better and/or more efficiently than Val158-carrying individuals (Barnett et al. 2007b; Mier et al. 2009). Conversely, the Val158 allele is associated with more “flexible” cognitive responses (Bilder et al. 2004), something which may be more adaptive during emotional processing (Smolka et al. 2005; Drabant et al. 2006). Apart from Val158Met, most other common COMT SNPs are non-coding (synony- mous, intronic, or in the 50 or 30-untranslated regions). As such, any functional impact they confer is presumably mediated by an effect on COMT expression. However, direct evidence for this hypothesis remains unclear (Bray et al. 2003; Chen et al. 2004; Tunbridge et al. 2004b; Dempster et al. 2006) and is likely complicated by non-linear interactions between SNPs within COMT (Meyer- Lindenberg et al. 2006; Nackley et al. 2006). An elegant demonstration of this was provided by Nackley et al. (2006), who demonstrated that different COMT haplotypes can result in different COMT mRNA secondary structure, thereby affecting its mRNA stability, protein expression, and enzyme activity in a manner 122 E.M. Tunbridge and P.J. Harrison that could not be predicted by examining any one of the haplotype-comprising SNPs individually. In any event, the majority of studies informing of sexually dimorphic effects of COMT have studied Val158Met; therefore, this polymorphism is the main focus of this review. 2 Sexual Dimorphisms in COMT Function COMT exhibits sexual dimorphisms in the normal brain that set the scene for, and may contribute to, differences in its involvement in psychiatric disorders between men and women. An important study by Chen et al. (2004), involving post-mortem brain tissue from 118 subjects, showed COMT activity in the prefrontal cortex to be 17% higher in men than women (independent of Val158Met and other SNPs). These findings are in agreement with earlier studies that demonstrated approximately 30% higher enzyme activity in men in liver (Boudikova et al. 1990) and also in most (Fahndrich et al. 1980; Floderus and Wetterberg 1981; Philippu et al. 1981) but not all (Fitzgerald et al. 1980) studies of erythrocytes. It is not known at what stage in life the sex difference in brain COMT activity manifests, since the sole develop- mental study was conducted almost entirely in males (Tunbridge et al. 2007a). Interestingly, the higher brain COMT activity in men occurs despite levels of COMT protein and mRNA being similar in both sexes (Bray et al. 2003; Chen et al. 2004; Tunbridge et al. 2004b) or perhaps even higher in women (Dempster et al. 2006). This dissociation between expression and activity has implications for the likely mechanism underlying COMT’s sexual dimorphisms, as we discuss later. The other primary evidence for sexual dimorphism in normal COMT function comes from examination of neurochemical function and behaviour of the COMT knockout mouse (Gogos et al. 1998). Tissue dopamine levels in the frontal cortex are increased almost threefold in male COMT/mice (and twofold in +/mice) compared to wild-type mice, confirming the importance of COMT in cortical dopamine metabolism; conversely, in female COMT +/ and/mice, dopamine levels were unchanged. The lack of effect of COMT deletion on frontal cortex dopamine in female mice presumably reflects the existence of sex-specific com- pensatory mechanisms (such as a higher activity of dopamine or noradrenaline transporters), although this has not been determined. Male, but not female, COMT knockout mice perform better on certain memory tests, showing higher levels of spontaneous alteration and better performance on the Barnes maze task than wild- type mice (Babovic et al. 2007). Similarly, male but not female knockout mice also have a significantly higher preference for ethanol, compared with their wild-type littermates (Tammimäki et al. 2008). In contrast, female but not male COMT null mice showed greater anxiety compared to wild-type mice (Gogos et al. 1998). These latter data suggest that COMT deletion is still of functional significance in female mice, despite the lack of an alteration in frontal dopamine. It is plausible that the anxiety changes in female COMT knockout mice results from the action of COMT in the hippocampus, a brain region which is critical for modulating anxiety Importance of the COMT Gene for Sex Differences in Brain Function and Predisposition 123 phenotypes (Gray and McNaughton 2000) and in which COMT is highly expressed. However, the role of COMT in the hippocampus remains to be investigated. Further studies in the COMT knockout mice, using cocaine, GBR 12909 (a dopamine transporter inhibitor), levodopa, or amphetamine to pharmacologically modulate dopamine levels, showed that some but not all neurochemical and behavioural responses to these pharmacological challenges are sex-specific (Huotari et al. 2002a,b, 2004; see also O’Tuathaigh et al. 2007). For example, D-amphetamine administration affected dopamine metabolism equally in male and female knockout mice (Huotari et al. 2004), whereas hyperactivity in response to GBR 12909 was attenuated only in males (Huotari et al. 2002b). A final noteworthy COMT sexual dimorphism concerns the potential for sex differences in allele frequencies. In 4,014 Ashkenazi Jews (control subjects parti- cipating in a genetic association study of schizophrenia discussed below), Shifman et al. (2002) found that the frequency of the A allele of the 30-untranslated region SNP rs165599 was higher in women than men (65% vs. 61%, p ¼ 0.0009); they state that a similar difference was seen in a second sample, giving a combined p value of 0.00009 (see also Shifman et al. 2004). The authors speculate that the finding may be due to a reduced viability of male foetuses carrying this allele. However, to our knowledge, this sex difference in rs165599 allele frequency has not been replicated (Sweet et al. 2005; see also Molero et al. 2007) – albeit no other study has reported on such a large sample – and so its significance remains unclear. 3 Sexually Dimorphic Effects of COMT Genotype on Brain Function and Psychiatric Disorders Listed in Table 1 are many (but not all) of the studies that have reported a sex difference in the impact of COMT genotype on a cognitive or psychiatric pheno- type. Patsopoulos et al. (2007) highlight that the majority of articles claiming sex differences fail to provide satisfactory evidence to support this claim. In part consistent with this assertion, the studies listed vary in the robustness and plausi- bility of the finding with regard to sex. Few have been statistically convincing, for example, by demonstrating a sex-by-genotype interaction in analysis of variance (ANOVA; e.g. Kates et al. 2006; Lang et al. 2007). Many studies simply found an association that reached significance in one sex but not in the other (e.g. Enoch et al. 2006). Findings of a significant difference in one sex and not in the other were often further compromised by the fact that the non-significant sex had a smaller sample size and therefore had less power to detect an effect, compared with the significant sex (e.g. Nolan et al. 2000; Ono et al. 2004; Stein et al. 2005). Other studies discuss sex-related effects despite reporting a non-significant sex-by-genotype ANOVA interaction (e.g. Olsson et al. 2005; Zinkstok et al. 2006), while a final category of studies, not included in the table, provide only trend-level findings of sex-related effects of COMT genotype (e.g. Eley et al. 2003; Sazci et al. 2004;Woo et al. 2004). 124 E.M. Tunbridge and P.J. Harrison Table 1 Chronological list of studies reporting sexually dimorphic effects of COMT genotype on psychiatric disorders and allied phenotypesa Citation Phenotype/parameter Male/females Finding related to sex Karayiorgou et al. OCD 117/104 Met158 allele associated in men (p ¼ 0.0002) not women (p ¼ 0.066) (1997)b Nolan et al. (2000) Suicide attempts in 117/31 Met158 allele associated in men (p ¼ 0.028) not women (p > 0.5) schizophrenia Dauvilliers et al. (2001) Sleep latency in narcolepsy 59/38 Longer latency associated with Met158 allele in men, Val158 allele in women Shifman et al. (2002)b Schizophrenia 3,980/1,643 G allele of rs165599 associated in women (p < 0.00001) not men (p ¼ 0.1). Sex difference p ¼ 0.01 Enoch et al. (2003) Harm avoidance 160/241 Met158 homozygosity associated in women (p  0.03) not men (p  0.79) Qian et al. (2003) ADHD 170 case, 376 control/18 Met158 associated with ADHD in males (p ¼ 0.05; family-based study), while case, 17 control Val158 associated in females (p ¼ 0.044; case control) Domschke et al. (2004) Panic disorder 82/148 Val158 allele associated in women (p ¼ 0.01) not men (p ¼ 1.0) Ono et al. (2004) Suicide 112/51 Val158 homozygosity protective in men (p ¼ 0.016) not women (p ¼ 0.96) Olsson et al. (2005) Persistent episodic anxiety 340/473 Met158 homozygosity associated in women (p ¼ 0.02) not men (p ¼ 0.38). No genotype  sex interaction Poyurovsky et al. OCD 109/141 Met158 allele associated in men (p ¼ 0.029) not women (p ¼ 0.78) (2005) Stein et al. (2005) Low extraversion 154/343c Met158 homozygosity associated in women (p ¼ 0.001) not men (p ¼ 0.6) Sweet et al. (2005) Psychosis in Alzheimer’s 130/243c Val158 allele associated in women (p ¼ 0.005) not men (p ¼ 0.383) disease Kates et al. (2006)b Dorsal and orbital frontal 25/26 Opposite effects in boys and girls with VCFSd. Sex x genotype interaction volumes (p < 0.001) Beuten et al. (2006)b Nicotine dependence 668e/1369c,e Met158 allele associated in women. Sex  genotype interactions (0.006 < p < 0.02) Denys et al. (2006) OCD 135/170 Met158 allele associated in men (p ¼ 0.036) not women (p ¼ 0.23) Enoch et al. (2006) Alcoholism and smoking 141/201 Val158 allele associated in women (p ¼ 0.011) not men (p ¼ 0.186) Kim et al. (2006) Harm avoidance 138/148 Val158 allele associated in women (p ¼ 0.003) not men (p ¼ 0.36) O’Hara et al. (2006) Delayed verbal recall tests 62f/101f Val158 allele associated with 8 point WMS-Rg advantage in men. Sex  genotype interaction on BNTh Rothe et al. (2006) Panic disorder 60/118e Val158 allele associated in women (p ¼ 0.008) not men (p ¼ 0.272) Rybakowski et al. WCSTi in schizophrenia 43/36 Val158 homozygosity associated with fewer errors by men (p ¼ 0.044), more errors (2006) by women (p ¼ 0.042) Zinkstok et al. (2006) Grey and white matter 57/97 Ageing effects related to genotype in women only. No genotype  sex interactions volumes Barnett et al. (2007a)b IQ and executive function 2,650j,k/2,650j,k Effects in boys only. Genotype  sex interactions on attention and verbal IQ Importance of the COMT Gene for Sex Differences in Brain Function and Predisposition 125 Baud et al. (2007) Trait anger in suicide 211/536 Val158 homozygosity associated with higher trait anger in women (p ¼ 0.002) but attempters not men Domschke et al. Panic disorder 209/319 Meta-analysis. Association in women only: Val allele in Caucasians, Met allele in (2007)b Asians Golimbet et al. (2007) Novelty seeking 56/74 Met158 homozygosity associated with higher trait scores in women (p ¼ 0.018) not men Lang et al. (2007)b Sensation seeking 214/218 Val158 homozygosity associated in women (p  0.005) not menl. Sex  genotype interaction (p ¼ 0.005) Ma et al. (2007) Schizotypy in healthy 231/234 Val158 homozygosity associated with lower schizotypy scores in men (p ¼ 0.009) volunteers but not women Pooley et al. (2007)b OCD 580/718 Meta-analysis. Met158 allele associated in men (p ¼ .001) not women (p ¼ 0.83). Sex difference p ¼ 0.0001 Weiss et al. (2007) Emotional recognition 49/51 Met158 homozygosity associated with impaired recognition of sad faces in women (p ¼ 0.03) not men Zhang et al. (2007) WISCm 142/163 Freedom from distractibility scores associated in girls (p-0.03; 0.06 after Bonferroni) but not boys Barnett et al. (2008) Meta-analysis of Val158Met N-back: negative association between study effect size and proportion of males and cognitive measures (p < 0.001). Verbal recall: positive association between study

effect size and number of male participants (p ¼ 0.007) Biederman et al. (2008) ADHDn 308/166 Met158 allele associated in males (p ¼ 0.003) but not females. Sex effect: p ¼ 0.071; significance increases to p ¼ 0.007 when combined with Qian et al. (2003) Oosterhuis et al. (2008) Opiate 11 case, 50 control/18 Met158 associated with dependence in female Hispanics (p ¼ 0.049). Does not dependence case, 43 control survive multiple testing correction and not found in other ethnicities Pelayo-Terán et al. Schizophrenia clinical 63/40 Val158 associated with longer duration of untreated psychosis in females (2008) characteristics (p ¼ 0.011) but not males. Sex  genotype interaction: p ¼ 0.011 Talkowski et al. Schizophrenia Not stated (478 cases, 501 rs737865 associated in women (p ¼ 0.008) but not men. Sex  genotype (2008)b controls) interaction: p ¼ 0.0007 Barnett et al. (2009)b IQ and cognition 4211/3962 COMT haplotype associated with verbal IQ in boys but not girls. Sex  genotype interaction (p ¼ 0.03). Working memory span associated with rs165599 in boys but not girls. Sex  genotype interaction: p ¼ 0.02 Domschke et al. (2009) Therapeutic response to 33/71 Val158 allele associated with better response in females (p ¼ 0.016) but not ECTo significant in males (although magnitude of change was similar in both groups) (continued) 126 E.M. Tunbridge and P.J. Harrison Table 1 (continued) Citation Phenotype/parameter Male/females Finding related to sex Hoenicka et al. (2009) Schizophrenia 226 cases, 117 controls/ Val158 homozygosity associated in men (p ¼ 0.022) but not women 111 cases, 114 controls Katerberg et al. (2009) OCD and patient phenotypic 151 cases, 235 controls/ Met158 associated with OCD in men (p ¼ 0.039) but not women. Increased characteristics 222 cases, 227 frequency of Met158 allele in women compared with men (p ¼ 0.012). controls Sex  genotype interaction on OCD phenotype: heterozygous women showed a lower level of somatic and sensory symptoms compared with homozygotes (p ¼ 0.024) but this relationship was absent in men Kempton et al. (2009) Brain activation during 40/34 Val158Met modulates brain activation in regions differing between men and fearful affect processing women. Sex  genotype interaction significant in right temporal pole (p ¼ 0.028): female Val158 activate > Met158, while male Met158 deactivate > Val158 Quednow et al. (2009) PPIp 54/53 Met158 associated with higher PPI in men (p < 0.05) but not women Tsai et al. (2009) Fluoxetine response in major 138/196 Val158 associated with poorer response in men (p ¼ 0.035) but not women depression aFindings all relate to Val158Met polymorphism except where stated bKey studies, discussed in the text cHaplotypes containing Val158Met were also studied dVCFS: velo-cardio-facial syndrome (22q11 deletion syndrome) eCalculated from their Table 1 fElderly adults gWMS-R: Wechsler Memory Scale (Revised) hBNT: Boston Naming Test iWCST: Wisconsin Card Sorting Test jRepresentative number; exact sample size differed between tests kChildren lp value not stated mWeschler Intelligence Scale for Children nAttention-deficit hyperactivity disorder oElectroconvulsive therapy pPrepulse inhibition Importance of the COMT Gene for Sex Differences in Brain Function and Predisposition 127 It should be noted that some phenotypic associations with COMT are in the opposite direction in the two sexes, rather than just being limited to a significant finding in one or other sex (e.g. Dauvilliers et al. 2001; Rybakowski et al. 2006). Results of this nature may be correct; however, in the absence of a prior hypothesis, or replication, they may well be false positives. These confounds and limitations mean that most of the studies in the table are merely suggestive and do not by themselves provide convincing evidence that COMT genetic variation has a sexually dimorphic influence on the phenotype in question. Nevertheless, the number of studies showing at least some evidence for sexual dimorphisms is intriguing, especially as among the studies are several more striking and robust findings of this kind. We discuss these more robust findings further here. The first study to report a sex difference in the role of COMT in the genetic predisposition to a psychiatric disorder (Karayiorgou et al. 1997) showed that the low activity (Met158) allele was associated with OCD in men, but not in women in a case–control study. The authors later replicated this finding in a family-based study (Karayiorgou et al. 1999), and it was further replicated in three of four subsequent case–control studies (Poyurovksy et al. 2005; Denys et al. 2006; Pooley et al. 2007). This sex-selective association between the COMT Met158 allele and OCD was confirmed in a meta-analysis (Pooley et al. 2007); the odds ratio associated with the Met158 allele in men was 1.88 (p < 0.001), with no effect in women (odds ratio 0.98, p ¼ 0.83), and with a significant sex difference between the odds ratios (p < 0.0001). Although studies published since this meta-analysis have produced mixed results (Wray et al. 2008 found no association between COMT in men or women, while Katerberg et al. 2009 showed a trend-level association between Met158 and OCD in men but not in women, in line with the finding of Pooley et al.), the COMTOCD data are arguably the clearest evidence to date for a sexually dimorphic autosomal genetic association with a psychiatric disorder. Barnett et al. (2007a, 2009) also demonstrated a sexually dimorphic association between COMT and IQ. They genotyped initially the Val158Met SNP (Barnett et al. 2007a), and more recently the functional haplotype described by Nackley et al. (2006) (Barnett et al. 2009), in over 5,000 participants in a longitudinal study of child development, and in whom a range of cognitive tests, including IQ, attention, and working memory, had been conducted between ages 8 and 10. In the initial study, the Met158 allele was associated with better function in several domains, with these effects greater in, or limited to, boys. More recently, they demonstrated that the strength of these associations was even greater when the functional haplotype described by Nackley et al. (2006) (which appears to have a larger effect on COMT enzyme activity than Val158Met SNP alone) was considered. For example, in boys, Met158 homozygotes had a verbal IQ 3 points higher than Val158 homozygotes, whereas the difference in girls was less than 1 point. Strikingly, in the later study, the effect of the COMT haplotypes was even greater: boys carrying the COMT diplotype that predicted the highest enzyme activity had a verbal IQ 6 points lower, on average, when compared with boys with the diplotype predicting the lowest activity; again, there was no significant association between the COMT haplotypes 128 E.M. Tunbridge and P.J. Harrison and verbal IQ in girls (Barnett et al. 2009). Intriguingly, in their initial study Barnett et al. (2007a) also showed that the COMT effect on verbal IQ was greater in pubertal than pre-pubertal boys (increasing to a 10 point difference between homozygote groups), suggesting that its influence increases with sexual maturation (they did not comment on the effect of age in their subsequent study). An increasing effect of COMT around the age of puberty is consistent with data linking COMT Val158Met with verbal IQ in a longitudinal study of velocardiofacial syndrome (VCFS or 22q11 hemideletion syndrome, in which one copy of COMT is deleted; Gothelf et al. 2005). It is also consistent with significant maturational increases in COMT expression and activity in prefrontal cortex, although these changes weremost marked post-adolescence and not peri-pubertally (Tunbridge et al. 2007a). Kates et al. (2006) also studied the role of COMT Val158Met children with VCFS. Their finding, although in a small sample, is noteworthy because it concerns brain structure, and also because the dimorphism is statistically robust – a sex-by-genotype ANOVA interac- tion (p < 0.001), with an opposing effect of Val158Met allele on frontal cortical volumes in boys and girls. Taken together, these data, together with those of Zinkstok et al. (2006), raise the possibility of a complex interaction between COMT genotype, sex, brain structure, and development. Further evidence for sexually dimorphic associations between COMT and psy- chiatric phenotypes comes from hints that there may be sex differences in associa- tions between COMT and schizophrenia. Shifman et al. (2002) reported that homozygosity for the G allele at rs165599 of COMT was strongly associated with schizophrenia in women (p ¼ 6.8  106) but not in men (p ¼ 0.09), with the sex difference in genotype effect being significant (p < 0.01). The authors concluded that there may be a sex-specific genetic component to schizophrenia, while acknowledging that twin studies had not predicted this. However, a sex difference in the genetic association with schizophrenia was not present for the other COMT SNPs they analysed, nor was it observed for haplotypes (that included rs165599). Furthermore, as noted by Craddock et al. (2006), their finding was driven by the sexually dimorphic allele frequency in the control group, described above. More recently, Talkowski et al. (2008) reported a female-specific association between COMT rs737865 and schizophrenia (p ¼ 0.008) (but not in rs165599), in which the sex-by-genotype interaction was significant (p ¼ 0.0007). They also replicated a female-specific association at this locus in a second cohort, although it was the other allele which was significantly associated in this second samples. Notably, this sex-specific association occurred in the absence of any sex differences in allele frequencies in the control group; thus, these findings are perhaps more convincing than those of Shifman and colleagues. However, despite the statistical significance of these two studies, the results remain difficult to interpret vis à vis schizophrenia, and in need of replication, especially given the different polymorph- isms involved. The potential for sex differences in associations between COMT and schizophrenia is further complicated by the report of Sazci et al. (2004) of a female-predominant association (of Met158) with schizophrenia, and by the fact that the meta-analyses of COMT Val158Met with schizophrenia find no sex effect (Glatt et al. 2003; Fan et al. 2005). Thus, although these findings raise the intriguing Importance of the COMT Gene for Sex Differences in Brain Function and Predisposition 129 possibility that different loci within COMT may be differentially associated with schizophrenia in men vs. women, they should be considered preliminary and are in need of further investigation. A further sex-by-genotype interaction (p < 0.0005) was seen by Lang et al. (2007) who showed that the Val158 allele was associated with the personality trait of sensation seeking in women but not in men. This finding is the most statistically robust of a line of studies that show relationships between COMT genotype and personality traits in women but not in men. Of particular note, anxiety-related phenotypes (such as harm avoidance and neuroticism) have been repeatedly (though often weakly) associated in women with the Met158 allele (Eley et al. 2003; Enoch et al. 2003; Olsson et al. 2005; Stein et al. 2005), consistent with findings in anxiety disorder (Domschke et al. 2004; Woo et al. 2004; Rothe et al. 2006) and with the increased anxiety found in female, but not in male, COMT knockout mice, described above. A meta-analysis of the panic disorder studies (Domschke et al. 2007) confirmed the presence of a sex difference in the association with COMT. However, this study also revealed an additional complexity: the relationship interacted with ethnicity, such that panic disorder was associated with the Met158 allele in Caucasian women but with the Val158 allele in Asian women. The latter result is consistent with the findings of Kim et al. (2006), who showed a Val158 association with harm avoidance in Korean women. Two main explanations come to mind for the genotype-by-ethnicity interaction. First, given that the resulting subgroups are quite small and the p values modest (p ¼ 0.04 in Caucasians, p ¼ 0.02 in Asians; Domschke et al. 2007), the findings are quite likely to be false positives. Second, if true, the finding may relate to ethnic differences in the genetic background of the Val158Met polymorphism, such that the opposing allelic associations with panic disorder are both genuine (Lin et al. 2007). This possibility is quite plausible, given the complex manner in which SNPs in COMT have been shown to interact to regulate COMT activity (Nackley et al. 2006). It is interesting to note that the data reviewed here suggest that the Met158 allele is associated with anxiety phenotypes in (Caucasian) women but with OCD – usually considered to be a type of anxiety disorder – in men.

One interpretation is that Met158 is a risk factor for a shared predisposition to anxiety in both sexes, but that this manifests itself as different anxiety phenotypes in men and women because of other influences that are themselves sexually dimorphic, whether genetic, epige- netic, or environmental in origin. 4 Mechanisms Underlying Sex Differences in COMT’s Effects on Brain Function and Its Associations with Psychiatric Disorders Sexually dimorphic effects of COMT are normally explained by its regulation by oestrogens. Contemporary interest in oestrogenic COMT regulation can be traced to the work of Xie et al. (1999), although many years previously Axelrod had reported 130 E.M. Tunbridge and P.J. Harrison that 17-b-oestradiol (E2) administration decreased COMT activity in rat liver (Cohn and Axelrod 1971). Xie et al. (1999) identified two oestrogen response elements in the COMT promoter and showed that E2 at physiological concentra- tions inhibits COMT mRNA expression in cells expressing oestrogen receptors, but not in those which do not. The same group later showed that the oestrogen-mediated decrease in COMT mRNA was accompanied by a proportional decrease in COMT immunoreactivity and activity (Jiang et al. 2003). This inhibitory regulation by oestrogens is consistent not only with the normal sex differences in COMT activity noted above, but also with the evidence that women with high oestrogen states (e.g. on the combined oral contraceptive, or in the third trimester of pregnancy) have lower COMT activity than other women (Briggs and Briggs 1973). In post-meno- pausal women, oestrogen levels fall dramatically, to substantially below that of men of the same age (Bjornerem et al. 2004); it would be of interest to know whether sex differences in COMT activity (and its genetic associations) present in younger adults are lost or reversed in the elderly. In addition to itself being regulated by oestrogens, COMT in turn plays an important role in metabolising catechol oestrogens and thereby lowering levels of these potential carcinogens (Creveling 2003). There is both in vivo (Worda et al. 2003) and in vitro (Dawling et al. 2001; but see Goodman et al. 2002) evidence that the Val158Met SNP influences this pathway with greater E2 metabolism in those with the high activity Val158 allele, a finding that may also explain the associations reported in some studies between the COMT Met158 allele and oestrogenic cancers (Goodman et al. 2002). These complex, reciprocal, and partly genotype-influenced interactions between COMT and oestrogens may be relevant to the question of sexual dimorphism. COMT genotype may modulate the role that oestrogens play in brain function and dysfunction (Seeman 1997), while oestrogens affect COMT activity and therefore its associations with behaviour and psychiatric disorders by virtue of their influence on COMT gene expression. However, despite the focus on oestrogenic regulation of COMT gene expression, it is probably only a partial explanation for sex differences in COMT’s function. Although COMT mRNA expression is lower in peripheral tissue in women (Wang et al. 2009), Cohn and Axelrod (1971) found that E2 did not affect rat brain COMT activity despite its robust down-regulation in the liver. Consistent with these findings, Jiang et al. (2003) demonstrated oestrogenic regulation of COMT in a breast cancer cell line but not in a glioblastoma cell line, again suggesting that this relationship may not pertain in the brain. The suggestion that oestrogenic regulation of COMTmRNA abundance may be less important for mediating COMT’s sex differences in the brain, compared with the periphery, is supported by several recent human post-mortem brain studies showing that COMT activity is higher in men (Chen et al. 2004) even though COMT mRNA abundance is the same (Tunbridge et al. 2004b; Chen et al. 2004) or even higher (Dempster et al. 2006) in women. Hence, for a given level of COMT mRNA abundance, COMT activity in the male brain is higher than it is in females, and therefore the sexual dimorphism cannot be readily explained by tran- scriptional regulation. This fact also argues against potential explanations for sex differences in COMT based on epigenetic regulation of COMT mRNA (Kaminsky Importance of the COMT Gene for Sex Differences in Brain Function and Predisposition 131 et al. 2006); in any event, there is no evidence for a sex difference in COMT promoter methylation status (Abdolmaleky et al. 2006). Finally, the finding that COMT protein and activity levels rise considerably in men between the third and fifth decade of life (Tunbridge et al. 2007a), despite steady oestradiol levels across this period (Bjornerem et al. 2004) emphasises that oestrogens are not the only factor responsible for regulating COMT activity in the brain. The mechanism mediating a sex difference in COMT activity in the absence of a difference in COMT mRNA and protein abundance is unknown. It is possible that the discrepancy is in fact spurious, since localised or phasic sex differences in COMT mRNA or protein abundance in brain – e.g. in specific cell types, or in relation to menstrual cycle – are likely, based on evidence from peripheral tissue (Salih et al. 2008). However, the fact that a robust sex difference in COMT enzyme activity was seen with no hint of a sex difference in COMT protein measured in the same samples (Chen et al. 2004) suggests that it is genuine. As such, one possibility is that it reflects a sex difference in the relative abundance of novel mRNA (Tunbridge et al. 2007b) or protein (Tunbridge et al. 2006b) isoforms of COMT, which could differ in their enzyme activity and might not affect the amount of total COMT mRNA or protein. Or, there could be a sex difference in the abundance of co-factors, endogenous inhibitors (e.g. S-adenosylmethionine [SAM]; Zhu 2002), or interacting proteins that modulate COMT activity. In support of the hypothesis that SAM levels may be rate-limiting in the female brain, there are hints from a small pilot study that SAM augmentation may be therapeutically beneficial for depressive symptoms for women but not for men (Strous et al. 2009) More broadly, sexual dimorphisms in COMT occur against a background of sex differences in its biochemical pathways. In addition to differences between females and males in terms of catechol oestrogen function, the dopamine system is mark- edly sexually dimorphic (Di Paolo 1994; Becker 1999; Andersen and Teicher 2000; Carroll et al. 2004). For example, women have higher striatal [18F]fluorodopa uptake, suggesting greater presynaptic dopamine synthesis (Laakso et al. 2002), and a lower D2 receptor affinity (Pohjalainen et al. 1998) than men, which the authors hypothesise reflects higher dopamine levels in the female brain at baseline. Conversely, women have lower amphetamine-stimulated dopamine release (Munro et al. 2006), and a greater dopamine transporter uptake, suggestive of more rapid clearance of dopamine from the synaptic cleft (Mozley et al. 2001). Thus, compared with men, women appear to have elevated basal, but decreased stimulated, striatal dopamine levels. Taken together, these findings may indicate a difference in the balance between tonic and phasic dopamine between women and men, a parameter which is also hypothesised to be regulated by COMT activity (Bilder et al. 2004). However, oestrogenic state (e.g. phase of menstrual cycle) has not been fully taken into account in these studies and may be a significant confounder: rodent studies have shown marked fluctuations in multiple dopaminergic parameters in the stria- tum across the oestrus cycle (Jori and Cecchetti 1973, Favis et al. 1977, Crowley et al. 1978; Fernandez-Ruiz et al. 1991; Morissette and Di Paolo 1993; Xiao and Becker 1994). Sex differences in dopamine function are less well studied outside the striatum; therefore little information is available to inform on relative 132 E.M. Tunbridge and P.J. Harrison dopaminergic function in the sex differences in cortical regions where COMT is likely to have its primary impact (Karoum et al. 1994; Gogos et al. 1998; Tunbridge et al. 2004a; Yavich et al. 2007). Cortical tissue dopamine concentrations are reportedly similar in men and women (Robinson et al. 1977), although women may have a higher extra-striatal D2 receptor-binding potential (Kaasinen et al. 2001). In summary, there are diverse data suggesting substantial sex differences in central dopamine parameters (Cosgrove et al. 2007). However, it is not clear what their net effect is upon dopaminergic function in men compared to women, nor how the dopaminergic sexual dimorphisms impinge upon the inverted U-shaped relationship between dopamine activity and prefrontal function (Goldman-Rakic et al. 2000) known to be regulated by COMT activity (Mattay et al. 2003; Tun- bridge et al. 2006a; Williams-Gray et al. 2007) and likely to be sensitive to interactive effects of COMT with other genes (Talkowski et al. 2008; Tan et al. 2007) and environmental factors (Caspi et al. 2005). 5 Conclusions Genetic epidemiological and other studies show that sex differences in the genetic architecture of many human phenotypes, including psychiatric disorders, are com- mon. There is also a substantial literature attesting to male–female differences across many domains of brain function, structure, and development. The data reviewed here suggest that COMT is one of the genes that contribute to these sexual dimorphisms. In addition to a difference in COMT enzyme activity between men and women, there is evidence that the involvement of COMT in predisposition to OCD and anxiety phenotypes is sex-specific, and weaker evidence for sex differences in its roles in several other phenotypes. Not all COMT genotypic associations are demonstrably sexually dimorphic; for example, its influence on Wisconsin Card Sort Test performance (Barnett et al. 2007b) and on homocysteine metabolism (Tunbridge et al. 2008). Neither is COMT the only autosomal gene for which sexually dimorphic genetic associations with psychiatric phenotypes have been reported; using schizophrenia as an example, reelin is reportedly associated only in women (Shifman et al. 2008), while GNB1L (Williams et al. 2008) and MTHFR have been associated only in men (Sazci et al. 2005; Kempisty et al. 2006). However, the data do appear more extensive, and in places statistically more convincing, for COMT than for any other autosomal gene we could determine. Furthermore, as we have discussed, the findings parallel sex differences found in the COMT knockout mouse, and are complemented by the sexual dimorphism in COMT activity and by a plausible, if incomplete, mechanistic explanation in terms of oestrogenic regulation. As such, COMT may well contrib- ute to the genetic basis for sexual dimorphisms in human brain, behaviour, and - related disorders, although it is clearly but one of many genes acting in this way, and in isolation explains only a tiny proportion of the variance. 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Neurosci Lett 405:34–39 Sex Differences and Hormonal Influences in Human Sensorimotor Gating: Implications for Schizophrenia Veena Kumari Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 2 Prepulse-Elicited Startle Modulation (PESM) as a Measure of Sensorimotor Gating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 3 PESM Deficits in Schizophrenia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 4 Sex Differences and Menstrual Phase Effects

in PESM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 5 Hormonal Influences in PESM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 6 Consideration of Sex and Hormonal Influences in PSEM in the Context of Schizophrenia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 7 Conclusions and Directions for Future Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Abstract Prepulse inhibition (PPI) of the startle response serves to prevent the interruption of ongoing perceptual and early sensory analysis and provides a simple operational measure of sensorimotor gating. In line with postulated deficits in early stages of information processing, PPI is disrupted in schizophrenia. PPI is consid- ered a valid candidate for an endophenotypic marker in genetic studies of schizo- phrenia and has also been extensively used in translational research. Importantly, there are well-replicated sex differences and menstrual phase effects in prepulse- elicited startle modulation of nonclinical young populations. Lack of knowledge about the precise roles of sex differences and hormonal effects in prepulse-elicited startle modulation and in the schizophrenia disease process presents a stumbling block to continuous progress in this field. This chapter reviews a wealth of data demonstrating sex and hormonal influences in prepulse-elicited startle modulation and considers their implications for our understanding of the pathophysiology, genetics, and potential treatments of schizophrenia. V. Kumari Department of Psychology, Institute of Psychiatry, King’s College London, De Crespigny Park, London SE5 8AF, UK e-mail: veena.kumari@kcl.ac.uk J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 141 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010_117, # Springer‐Verlag Berlin Heidelberg 2011, published online 4 March 2011 142 V. Kumari Keywords Estrogen
Hormones
Prepulse facilitation
Prepulse inhibition
Progesterone
Schizophrenia
Sex
Startle response 1 Introduction Schizophrenia is a severe neuropsychiatric disorder of unknown etiology. The condi- tion is clinically heterogeneous and often results in disabling cognitive, perceptual, and emotional symptoms. The symptoms are generally classified as positive (e.g., hallucinations and delusions), negative (e.g., anhedonia, thought paucity), and cogni- tive (e.g., thought disorder, bizarre thinking). There are well-established sex differ- ences in onset, prognosis, and course of this disorder (Hafner 2003). Current pharmacological treatments, largely involving blockade of dopamine D2 receptors (Kapur and Remington 2001; Guillin et al. 2007), are effective in reducing the acute symptoms but provide no cure. Accordingly, the need for a better understanding of the etiology and pathophysiology of schizophrenia and the development of novel treatments persists. The future of drug development in schizophrenia depends on many experimental strategies as well as on serendipity (Carpenter and Koenig 2008; Javitt et al. 2008). Over the last 30–40 years, translational models, such as prepulse inhibition (PPI) of the startle response, have played an important role in the strategic effort to develop and characterize new treatments. The aim of this chapter is to review sex differences and menstrual phase effects in PPI of nonclinical young populations and discuss their implications with a view to advance our understanding of the pathophysiology, genetics, and treatment of schizophrenia. 2 Prepulse-Elicited Startle Modulation (PESM) as a Measure of Sensorimotor Gating The startle reflex consists of a set of reflexive, involuntary responses to a sudden, intense stimulus. It is known to exhibit several forms of plasticity which are remarkably similar in animals and humans, examples being habituation (Hoffman and Searle 1968) and fear potentiation (Brown et al. 1951). A further example of startle plasticity is that the startle response can be modified reliably by presenting a more innocuous stimulus (prepulse) before the strong startle-eliciting stimulus (pulse) (Graham 1975). When the time from prepulse onset to pulse onset, or stimulus onset asynchrony (SOA), is between 30 and 500 ms, such modification will appear as inhibition (PPI), evident as the attenuation of the startle response (Fig. 1). However, with a longer interval between the prepulse and the pulse, such modification will appear as facilitation of the startle response (PPF) (Fig. 1). PESM is increasingly being used as a measure of early and late information processing in experimental animals as well as in clinical and nonclinical human populations. PPI is considered to provide an operational index of sensorimotor gating: while information processing resources are targeted at the prepulse, any incoming Sex Differences and Hormonal Influences in Human Sensorimotor Gating 143 Fig. 1 PPI and PPF effects information (i.e., the pulse) is attended to a reduced level, thereby protecting the processing of the initial stimulus (i.e., the prepulse). A reduced ability to gate (or filter out) such stimulus interference (i.e., reduced PPI) has been associated with sensory overstimulation and confusion (Geyer et al. 1990). Animal studies show that PPI is mediated by brain stem circuits involving the inferior colliculus, pedunculopontine tegmental nucleus, laterodorsal tegmental nucleus, substantia nigra pars reticulata, and caudal pontine reticular nucleus (Fendt et al. 2001) and modulated by forebrain circuits involving the prefrontal cortex, thalamus, hippo- campus, amygdala, nucleus accumbens, striatum, ventral pallidum, globus pallidus, and subpallidal efferents to the pedunculopontine nucleus (Swerdlow et al. 2001, 2008). Although the neural substrates of PPI may vary somewhat between animals and humans (Swerdlow et al. 2008), imaging studies (Hazlett and Buchsbaum 2001; Kumari et al. 2003b, 2005a, 2007a; Postma et al. 2006; Hazlett et al. 2008) support the involvement of similar brain regions in modulation of human PPI. PPF is a relatively less well-studied phenomenon. It may reflect sustained attention (Dawson et al. 1997), sensory enhancement linked with modality (Anthony 1985), or a different aspect of the same mechanism underlying PPI (Kumari et al. 2003a). The neural substrates of PPF are not well studied even in animals. In the only study (Neuner et al. 2010) to have investigated the neural substrates of PPF (in healthy men only), many regions, consistent with previous PPI studies, were found to be activated for both PPI and PPF. 3 PESM Deficits in Schizophrenia Graham (1975) suggested that “startle modulation might provide a powerful technique for probing what underlies the normal processing of information and especially for probing processing characteristics of relatively inaccessible subjects” (p. 238). Applying this to schizophrenia patients, Braff et al. (1978) demonstrated 144 V. Kumari impaired PPI confirming theorized deficits in early stages of information processing in this population. Many subsequent studies have replicated and refined this finding (Braff et al. 2001; Kumari et al. 2004, 2007b, 2008c; Swerdlow et al. 2006a; Takahashi et al. 2008). It has been hypothesized that a breakdown in the gating system causes sensory overload (Gottschalk et al. 1972) with secondary cognitive fragmentation, thought disorder, and possibly other psychotic symptoms in this clinical population (Braff and Geyer 1990). PPF is not as widely studied as PPI but is also impaired in schizophrenia, especially in female patients compared to female controls (Kumari et al. 2004). PPI, given its high temporal stability (Abel et al. 1998; Cadenhead et al. 1999) and amenability to cross-species comparisons (Swerdlow et al. 1994), is one of the leading animal paradigms dominating research on antipsychotic drug activity and in other comparative psychopharmacological studies (Geyer et al. 2001; Swerdlow et al. 2006b; Talledo et al. 2009). Attesting the usefulness of PPI as a translational model, an emerging body of evidence suggests that second generation antipsycho- tics may attenuate the PPI deficit in schizophrenia (Kumari et al. 2000, 2007a; Swerdlow et al. 2006a). PPI has also been recommended as a valid candidate for an endophenotypic marker in genetic studies of schizophrenia for several reasons. First, PPI is heritable with genetic factors contributing to 30–50% of the variance (Greenwood et al. 2007; Hasenkamp et al. 2010). Second, PPI is reduced not only in patients but also in schizophrenia-spectrum populations, for example, in unaffected biological rela- tives of schizophrenia patients (Cadenhead et al. 2000; Kumari et al. 2005b) and people with schizotypal personality disorder (Cadenhead et al. 2000) or high scores on psychometric measures of psychosis-proneness (Kumari et al. 1997, 2008b; Evans et al. 2005). Third, PPI is influenced by schizophrenia-relevant single nucleotide polymorphisms (SNPs) within the dopamine, serotonin, and acetylcho- line systems (Quednow et al. 2008, 2009; Roussos et al. 2008a, b; Petrovsky et al. 2010). However, some of the genetically mediated effects in PPI found reliably in healthy men may not be present in healthy women who are tested without regard to their menstrual cycle phase. For example, catecholO-methyltransferase Val158Met SNP has been reported to significantly influence PPI in independent samples of healthy men (Roussos et al. 2008b; Quednow et al. 2009) but not of healthy women (Montag et al. 2008; Quednow et al. 2009). The most likely reason for this is menstrual cycle-related variability in PPI of healthy young women (next section). It is becoming increasing obvious that sex differences and hormonal influences need to be considered in future applications of PESM models in the context of schizo- phrenia and other disorders that are characterized by disrupted sensorimotor gating. 4 Sex Differences and Menstrual Phase Effects in PESM PPI is sexually dimorphic (Fig. 2) with several studies reporting less PPI in healthy young women, when tested regardless of where they are in their menstrual cycle, than in healthy young men (Swerdlow et al. 1993, 1999; Abel et al. 1998; Sex Differences and Hormonal Influences in Human Sensorimotor Gating 145 Women 60 Men 50 40 30 20 10 0 –10 –20 –30 30-ms 60-ms 120-ms 240-ms 480-ms 1000-ms 2000-ms Prepulse-to-pulse interval Fig. 2 Sex differences in PPI and PPF (data from Aasen et al. 2005). PPI and PPF ¼ ([a  b])/ a  100, where “a” ¼ amplitude over pulse-alone trials, and “b” ¼ amplitude over prepulse trials (PPF is expressed as a negative value). PPI is seen to increase from 30-ms through 60-ms to 120-ms prepulse-to-pulse intervals, then to decrease and turn into PPF at 1,000-ms prepulse- to-pulse interval, especially in women. More PPI is present in men and more PPF in women Kumari et al. 2003a, 2004, 2008a; Aasen et al. 2005). The sex difference in PPI of nonclinical young people remains true after possible confounds, such as cigarette smoking and personality, are controlled for (Swerdlow et al. 1999; Aasen et al. 2005). A sex effect in PPI (females < males) has also been reported in rats (Koch 1998; Faraday et al. 1999) and mice (Ison and Allen 2007). PPI is sensitive to menstrual cycle status in healthy women, with more PPI observed during the early follicular phase relative to the luteal phase in both cross- sectional (Swerdlow et al. 1997) and within-subjects studies (Jovanovic et al. 2004; Kumari et al. 2010). Healthy pregnant women in their third trimester, when the levels of both estrogen and progesterone are roughly 50 times and 10 times (respectively) the levels in normally cycling women, have lower PPI in comparison with healthy postpartum women (Kask et al. 2008). Luteal phase young women show lower PPI in comparison with postmenopausal women (Bannbers et al. 2010). The

sex effect in PPI is not present in children under 8 years of age (Ornitz et al. 1991), in postmenopausal women compared to age-matched men (Kumari et al. 2008a) or aged mice (Ison and Allen 2007). Sex differences in PPF are less widely studied. Previous studies from our labora- tory suggest that healthy young menstruating women display higher PPF than men (Kumari et al. 2003a, 2004, 2008a; Aasen et al. 2005) (Fig. 2) and greater PPF during the luteal relative to the early follicular phase (Kumari et al. 2010) (Fig. 3). 5 Hormonal Influences in PESM Lower PPI during the luteal phase, compared to the early follicular phase, in healthy young women has been proposed to be caused by high levels of the ovarian hormone, estrogen (Swerdlow et al. 1997; Jovanovic et al. 2004). PPI is also % Prepulse inhibition (+) and facilitation (-) 146 V. Kumari Fig. 3 Menstrual phase effects in PPI and PPF (data from Kumari et al. 2010). PPI increases from 30-ms through 60-ms to 120-ms prepulse intervals during both the follicular and the luteal phases, then decreases and turns into PPF at 1,000-ms especially during the luteal phase. Significantly more PPI is seen during the follicular phase and significantly more PPF during the luteal phase reduced during periods of high estrogen in experimental animals (Vaillancourt et al. 2002). Estrogen influences various neurochemical activities including dopaminer- gic activity in the nucleus accumbens, an area critical for PPI both in experimental animals (Swerdlow et al. 2001) and in humans (Kumari et al. 2003b, 2005a). Administration of dopamine agonists, such as amphetamine or apomorphine, dis- rupts PPI in both rodents and human participants (Geyer et al. 2001; Swerdlow et al. 2003). Estradiol administration to ovariectomized rats has been reported to induce a decrease in the number of inhibitory synaptic inputs, an increase in the number of excitatory synapses, and an enhancement of the frequency of neuronal firing (Parducz et al. 2002). Since these findings fit the observed pattern of sex differences in PPI and PPF, we earlier suggested (Aasen et al. 2005) that women might show reduced PPI during the high estrogen phase of the menstrual cycle because estrogen elevates excitatory neuronal firing at the gate, inhibiting the gate to close as efficiently as men at short prepulse-to-pulse intervals and express increased PPF since the gate opens more efficiently at the long prepulse-to-pulse intervals com- pared to men. However, recent studies from our (Kumari et al. 2008a, 2010) and other laboratories (Talledo et al. 2009) have failed to detect a direct relationship between PPI and varying estrogen levels in healthy women, while in an earlier study estrogen administration (2 mg) prevented the disruption of PPI by buspirone, the serotonin-1A (5-HT1A) receptor partial agonist, but had no influence on PPI when given on its own to early follicular healthy women (Gogos et al. 2006). Perhaps progesterone, another ovarian hormone, plays a role in menstrual cycle- related variability in PPI as suggested by findings of our most recent study (Kumari et al. 2010). This study showed a smaller decrease in PPI from the follicular phase to the luteal phase in women who had a larger increase in progesterone. Sex Differences and Hormonal Influences in Human Sensorimotor Gating 147 Progesterone shows marked fluctuations over the menstrual cycle (Marshall 2001) and possesses psychotropic properties in addition to its role in reproductive endo- crinology (Rupprecht 2003). It is known to modulate the release of dopamine (Dluzen and Ramirez 1990; Ramirez and Zheng 1996) with biphasic effects, initially increasing but ultimately decreasing basal and amphetamine-stimulated dopamine release (Dluzen and Ramirez 1984). In rodents, progesterone reduces amphetamine-induced stereotypy (Michanek and Meyerson 1982). It is also impli- cated in the modulation of PPI (Rupprecht et al. 1999; Gogos and Van den Buuse 2004) and reverses apomorphine-induced disruption of PPI in rodents (Rupprecht et al. 1999). In healthy women, estrogen enhances the response to stimulant drugs, but this effect is masked in the presence of progesterone in healthy women (Justice and de Wit 1999). PPI, however, is sensitive not only to dopaminergic but also to serotonergic, glutamatergic, and cholinergic systems (Geyer et al. 2001; Swerdlow et al. 2008). Progesterone too, in addition to dopamine, affects other neurotransmit- ter systems. It is known to act as a functional antagonist at 5-HT3 receptors (Wetzel et al. 1998) and to have a role in the control of nicotinic cholinergic receptors (Valera et al. 1992). At present, it is unclear which of these systems might be most pertinent to the effect of progesterone in PPI of healthy young females. 6 Consideration of Sex and Hormonal Influences in PSEM in the Context of Schizophrenia The first issue deserving consideration is the roles of ovarian hormones in the schizophrenia disease process. A later age of illness onset, less severe forms of the illness, a superior response to antipsychotics, as well as better functional and social outcomes are reported for women than men with schizophrenia (Castle and Murray 1991; Faraone et al. 1994; Castle et al. 1995), supposedly due to a neuroprotective role of estrogen in women (Hafner et al. 1998; Kulkarni 2009). Female schizophrenia patients display greater symptom severity during the periods of low estrogen (e.g., postpartum) and lower symptom severity during the periods of high estrogen (e.g., pregnancy) (Riecher-Rossler et al. 1994). These observations showing “reduced symptoms” with “high estrogen” appear inconsistent with the earlier proposal (Swerdlow et al. 1997) that high estrogen during the luteal phase causes lower PPI in healthy women. It is, of course, possible that estrogen–PPI relationship follows an inverted U pattern with both very low and very high levels producing lower PPI or, as mentioned earlier, is modulated by another ovarian hormone, progesterone. Our recent finding did suggest a role for progesterone, more specifically an antipsychotic-like PPI-restorative action of progesterone, during the luteal phase in PPI of healthy young women (Kumari et al. 2010). Considering this finding in the context of schizophrenia, women are more suscepti- ble to the onset of schizophrenia after menopause and during the postpartum period (Hafner et al. 1993). This effect can be attributed to a drop in progesterone levels 148 V. Kumari (Shulman and Tibbo 2005). Studies have also reported high progesterone levels in unmedicated chronic patients in response to metabolic stress (Breier and Buchanan 1992) but normal progesterone levels in medicated patients with early psychosis (Oades and Schepker 1994) as well medicated chronic schizophrenia patients (Taherianfard and Shariaty 2004). Progesterone has been proposed to act as an endogenous antipsychotic and serve to restore normal function during times of stress (Shulman and Tibbo 2005). Further support for this notion comes from the reports that the progesterone metabolite 3a, 5a-THP produces a behavioral profile similar to that of dopamine receptor antagonists by increasing GABAergic tone in rodents (Khisti et al. 1998, 2002). Other data in rodents show increases in cortical progesterone and/or 3a, 5a-THP concentrations with olanzapine (Marx et al. 2000, 2003) and clozapine (Barbaccia et al. 2001; Marx et al. 2003), but not with haloperidol (Barbaccia et al. 2001). Atypical antipsychotic-induced increases in progesterone have been suggested to contribute to clinical benefits of these drugs (Barbaccia 2004; Marx et al. 2006). Studies so far have been incapable of disen- tangling the effect of estrogen and progesterone in human PESM. The second issue is whether the “normal” reduction in PPI of healthy young women during the luteal phase means the same as “deficient” PPI in schizophrenia and related populations. As suggested earlier (Kumari et al. 2003a), reduced PPI in healthy women during the luteal phase “may not be a simple reduction but rather a shift of the inhibition/facilitation curve in the direction of facilitation in women, relative to men.” At present, very few studies have examined both PPI and PPF in schizophrenia patients and not much is known about the pharmacology and neuro- anatomy of PPF even in animals. It is plausible that schizophrenia is associated not only with impaired PPI but also with a defect in mechanisms that underlie a smooth transition of PPI into PPF with increasing prepulse-to-pulse intervals in women during the luteal phase and appear to be modulated by ovarian hormones. 7 Conclusions and Directions for Future Research Given the importance of PPI as an animal model of schizophrenia and known sex differences in prognosis and course of this order, it is vital to uncover the biological basis of sex differences and menstrual cycle-related variations in PESM. While rodent studies in this area provide valuable information for hypothesis develop- ment, extrapolating their findings to humans is challenging because neuroanatomi- cally “the further forward one moves in the brain, the greater the anatomical and functional differences between rodents and humans” (Swerdlow et al. 2008). Due to poor understanding of sex and menstrual phase effects in human PESM, the majority of imaging and pharmacological studies so far have used mostly, if not exclusively, men. Their findings are unlikely to be applicable to healthy or ill women. Future studies investigating pharmacological and treatment effects using a prepulse modification paradigm in normal and clinical populations of both sexes would benefit from consideration of sex differences and menstrual phase effects and Sex Differences and Hormonal Influences in Human Sensorimotor Gating 149 assessments of both PPI and PPF. Future research should also aim to clarify the roles of varying ovarian hormones, especially estrogen and progesterone, in men- strual phase-related variability in PESM and establish whether menstrual phase- related variability in PPI and PPF is mediated by estrogen alone, progesterone alone, or via their interaction. 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Estrogens
Gonadal function
Psychoses
Schizophrenia Abbreviations ESR1 Endogen receptor-a HERS Heart and Estrogen/Progestin Replacement Study HRT Hormone replacement therapy PANSS Positive and negative syndrome scale RNA Ribonucleic acid WHI Women’s Health Initiative Study WHI-M Women’s Health Initiative Memory Study 1 Introduction Recent research increasingly points to the importance of estrogens and the hypo- thalamic–pituitary–gonadal axis in schizophrenia and related psychoses. On one hand, there are reports of gonadal dysfunction and states of estrogen deficiency in women with schizophrenia (the hypothesis of hypoestrogenism). On the other hand, there is mounting evidence from clinical as well as from epidemio- logical and basic research that estradiol, the main component of estrogens, exerts protective effects in schizophrenia and related psychoses (the estrogen protection hypothesis) (Riecher-Rössler and Häfner 1993). 2 Estrogens: A Protective Factor in Schizophrenia and Related Psychoses? (The “Estrogen Protection Hypothesis”) 2.1 Historical Findings As long ago as at the beginning of the last century, psychiatrists recognized the possible association between schizophrenia and estrogens (for review, see Riecher- Rössler and Häfner 1993). There are longstanding observations indicating an association between lowered estrogen blood levels and acute psychotic symptom- atology. Early clinicians such as Kraepelin and Kretschmer described signs of chronic “hypoestrogenism” in women with schizophrenia. Estrogens and Gonadal Function in Schizophrenia and Related Psychoses 157 Kraft-Ebing was among the first to describe women becoming psychotic before or during menstruation, i.e., when blood levels of estrogen are relatively low. Kraepelin even created a separate diagnostic category, labeled “menstrual psycho- sis”. Kretschmer reported cases where the outbreak of schizophrenia and related psychoses had a temporal relationship with “surgery of ovaries, pregnancy, deli- very, and puerperium”. Finally, Manfred Bleuler noted that late-onset schizophre- nia with onset after age 40 years was much more frequent in women than in men, a finding he attributed to the “loss of ovarian function” starting at around that age (for review, see Riecher-Rössler and Häfner 1993). 2.2 Basic Research Findings Important findings from basic research were the identification of estrogen receptors in the limbic system of the brain, and the observation that the effects of estrogens in rodents are, in some respects, similar to those of antipsychotic medications. Fur- thermore, it was shown that estrogens can modulate the sensitivity and number of dopamine receptors. It was therefore hypothesized that estrogens exert their anti- psychotic effects in a manner similar to that of traditional antipsychotic medications at least partly by blockade of dopaminergic transmission (Riecher-Rössler and Häfner 1993). We now know that estrogens, especially 17-b-estradiol (the natural estrogen that is most active in the brain), have many other neuroprotective and psychoprotective effects. For example, they appear to improve cerebral blood flow and glucose metabolism, promote neuronal sprouting and myelination, enhance synaptic density and plasticity, facilitate neuronal connectivity, act as antioxidants, and inhibit neuronal cell death. Estrogens have also been shown to exert profound effects on brain differentia- tion during development, particularly during late gestation and the early postnatal period, and are important in normal maintenance of brain function during aging (Cyr et al. 2002; Goldstein et al. 2002; Oesterlund 2002; Vedder and Behl 2005). In a well-controlled magnetic resonance imaging study, Goldstein et al. (2002) showed that normal patterns of sexual brain dimorphism (brain regions found to be structurally different in normal men and women) are disrupted in schizophrenia and related psychoses, especially in the cortex. Apart from later “activational” effects of circulating hormones (e.g., during puberty), those investigators suggested that these early “organizational” effects of gonadal hormones that occur during the developmental period (which is probably critical for at least some forms of schizo- phrenia and related psychoses) could be partly responsible for that finding. The mechanisms of action of estrogens are now known not only to depend on the classical genomic pathway but also to involve nongenomic, rapid interactions, which explain the differing latency of effects. They clearly modulate the dopami- nergic and other neurotransmitter systems that are believed to be relevant to schizophrenia and related psychoses, such as the serotonergic and glutamatergic 158 A. Riecher-Rössler and J. Kulkarni system, but also the noradrenergic and cholinergic system (for reviews, see Cyr et al. 2002; Oesterlund 2002; Garcia-Segura et al. 2001; McEwen 2002; Stahl 2001a, b). Recently it has even been suggested that 17-b-estradiol in the brain might rather be regarded as a neurotransmitter itself than as a hormone (Balthazart and Ball 2006). There are at least two subtypes of estrogen receptors, namely estrogen receptor-a and estrogen receptor-b, which are transcribed from two distinct genes (Oesterlund 2002). Autopsy studies showed that estrogen receptor-amessenger RNA is expressed in discrete areas of the human brain such as the amygdala, hypothalamus, cerebral cortex, and hippocampus; these areas are associated with neuroendocrine function, as well as emotion, memory, and cognition (Oesterlund et al. 2000). Recently Weickert et al. (2008) reported a variation in the endogen receptor-a (ESR1) gene to be associated with schizophrenia and speculated that the mecha- nism of this association may involve alternative gene regulation and transcript processing. Regarding the therapeutic effect of estrogens, it must also be noted that both the numerous direct effects on the brain and indirect

effects may play a role. For example, estrogens may also increase blood levels of antipsychotic drugs via their actions on liver metabolism (Yonkers et al. 1992). 2.3 Epidemiological Findings Epidemiological studies into sex differences in schizophrenic disorders suggest that the physiologically high estradiol production in young fertile women contributes to the later age of onset of schizophrenia in women as compared with men, to the second peak of onsets in women around the menopause, and to the better course of the disease in young women (Häfner et al. 1993; Riecher-Rössler et al. 1997). Thus, in an epidemiological study on a representative sample of 392 first admitted patients with schizophrenia, the ABC Study, we found that schizophrenic women have a later peak of illness onset in comparison with schizophrenic men (Häfner et al. 1991a, b; Riecher et al. 1991). They also exhibit an additional, smaller peak after age 45. We postulated that estrogens raise the vulnerability threshold for the outbreak of the disease. According to this hypothesis, women would be protected against schizophrenia between puberty and menopause to some extent by their relatively high gonadal estrogen production during this time. Then, around age 45, several years before menopause sets in at a mean age of 51.4 years, estrogen production begins to fall (Labhart 1978). Thus, women would lose the protection estrogens give, which could account for their second peak of illness onset after age 45. A number of risk factors appear to counteract the protective effect of estrogens. Thus, the sex difference in the age of onset diminishes in the subgroup of cases with a genetic risk and in patients with perinatal complications (Häfner 2005; Könnecke et al. 2000). Recent results regarding the age of menarche further support the hypothesis that physiological estrogens play a protective role against the development of the Estrogens and Gonadal Function in Schizophrenia and Related Psychoses 159 disease. We demonstrated a significantly later age of menarche in a representative group of first admitted women with schizophrenia and related psychoses as com- pared with a healthy control group (Riecher-Rössler 2002). Seeman and co-workers (Cohen et al. 1999; Hayeems and Seeman 2005) found that later menarche was associated with an earlier onset of the illness, an association that was independent of factors such as family history and obstetric complications. 2.4 Clinical Findings Clinically, psychotic symptomatology has often been found to correlate with the estrogenic state of women (for review, see Riecher-Rössler and Häfner 1993; Seeman 1996). For example, during high estrogen phases such as pregnancy, chronic psychoses appear to improve, whereas there is an excess of psychoses after delivery. Psychosis associated with estrogen withdrawal due to conditions other than the puerperium was recently reviewed by Mahe and Dumaine (2001). Those investi- gators reported cases of premenstrual psychosis, post abortion psychosis, and psychoses associated with removal of hydatiform mole, cessation of oral contra- ceptives, clomiphene and tamoxifen administration (both estrogen receptor antago- nists), and gonadorelin agonist administration (which blocks pituitary stimulation of endogenous estrogen secretion). Psychotic episodes were acute, short, and with a wide range of psychotic, but also affective, symptomatology. Recurrences were often reported when estrogen levels were normalized, and puerperal psychosis was frequent in the history of patients who were affected. Psychotic symptoms in schizophrenic patients have also often been shown to deteriorate premenstrually or perimenstrually (i.e., in the low estrogen phase of the cycle; for review, see Riecher-Rössler and Häfner 1993; Riecher-Rössler 2002; Seeman 1996). Thus, Riecher-Rössler et al. (1994a, b) could show an inverse correlation of estradiol blood levels with psychopathology. They examined 32 acutely admitted women with schizophrenia, who gave a history of regular men- strual cycles, and found a significant excess of admissions during the perimenstrual low estrogen phase of the cycle (p < 0.005). During the hospital stay of the 32 women, there emerged a significant association between estradiol levels on one hand, and psychopathology scores on the other hand. Psychopathology seemed to improve when estradiol blood levels rose and vice versa. This was true not only for the total score of the Brief Psychiatric Rating Scale (BPRS; Overall and Gorham 1962) and for almost all the subscores of this scale such as anergia, thought disturbance, activation, and hostile suspiciousness, but also for the general behavior on ward as rated by the nurses (NOSIE; Honigfeld et al. 1976) and for general well- being and paranoid feelings as rated by the patients themselves (BfS and paranoid subscore of PDS, both by von Zerssen and Koeller 1976). Also, Bergemann et al. (2007a) found a significant effect of the menstrual cycle phase and 17-b-estradiol levels on positive and negative symptoms of 125 women 160 A. Riecher-Rössler and J. Kulkarni with schizophrenia and related psychoses. The same authors (Bergemann et al. 2008) could furthermore show a significant effect of estrogen on the comprehension of metaphoric speech and/or concretism, a main feature of schizophrenic thought and language disturbance. Ko et al. (2006) similarly found that 35 women with chronic schizophrenia and related psychoses had low levels of estrogen which was associated with severe negative symptomatology and reduced cognitive function- ing, especially in the domains of verbal performance and executive tasks. Most studies, however, did not examine the correlation between psychosis symp- tomatology and estradiol serum levels directly. For example, a more recent study (Choi et al. 2001) reported behavioral, affective, and somatic symptoms of schizo- phrenia (not psychotic ones) to be associatedwith themenstrual cycle phase. Estradiol was not measured. Rather than examining cyclic fluctuations, Hoff et al. (1996) assessed the relationship between average estrogen levels from four consecutive weeks sam- pling with psychopathology and cognitive functioning in 22 female inpatients (aged between 22 and 63 years) with chronic schizophrenia. There was no significant association between average estrogen levels and psychopathology, but higher average estrogen levels were strongly associated with better cognitive abilities. However, this finding may be due in part to the effects of aging. It has to be noted that an elevated number of admissions during the perimenstrual period has also been identified in other disorders (Althaus et al. 2000), and exacer- bation of many psychiatric symptoms (not only psychotic ones) during the peri- menstrual period was observed in patients with schizophrenia and related psychoses (Riecher-Rössler et al. 1994b; Harris 1997). In theory, this lack of specificity is to be expected because of the multiple effects of estrogen on mental functioning. Studies on gender differences conducted in the area of late-onset schizophrenia emphasize the significance of hormone changes related to the menopause. Riecher- Rössler and colleagues (Riecher-Rössler et al. 1997; Riecher-Rössler 2002) showed that there are twice as many women as men with the onset of schizophrenia and related psychoses beyond 40 years of age, and that female patients with late-onset illness suffered from unexpectedly severe disease in terms of symptomatology and course. One explanation for this could be the fluctuation and sharp decline in estrogen levels just before and during the menopause. In support of this proposed explanation are results from long-term studies in women with schizophrenia showing that the course of illness in women tends to deteriorate rapidly during menopause and thereafter (for review, see Riecher-Rössler and Häfner 1993; Riecher-Rössler et al. 1998). 2.5 Intervention Studies Intervention studies have also been conducted over long periods, mainly with positive results (Korhonen et al. 1995; Lindamer et al. 1997) (for review, see Riecher-Rössler and Häfner 1993). Thus, as early as the 1940s, Manfred Bleuler (Bleuler 1943) reported the first unsystematic trials using a combination of ovarian Estrogens and Gonadal Function in Schizophrenia and Related Psychoses 161 and pituitary hormones. Mall (1960), a German psychiatrist in charge of a large hospital, examined 167 women suffering from schizophrenia with respect to estro- gen excretion in 24-h urine samples, basal temperature, and vaginal cytology. Based on his findings, he divided the psychoses into two groups: hypofollicular and hyperfollicular. In the former group, he replaced estrogens and found that “hypo- follicular psychosis can be healed relatively easily by this substitution therapy.” Unfortunately, Mall does not give many details about these interesting studies. In the first systematic trial conducted in 1996, Kulkarni et al. (1996) found that women with schizophrenia receiving estradiol as an adjunct to antipsychotic medi- cation treatment exhibited rapid and greater improvement in psychotic symptoms than women receiving antipsychotics only. In 2001, the same group performed a double-blind, 28-day, placebo-controlled study (Kulkarni et al. 2001) in which 12 women were administered transdermal 17-b-estradiol (patches) 50 mg/24 h, another 12 women received 100 mg/24 h patches, and the third group received placebo patches. The 100 mg group experienced greater improvement than either the 50 mg or placebo groups, with striking improvements observed in the key psychotic symptoms. Akhondzadeh et al. (2003) published a randomized study of 32 women of childbearing age with chronic schizophrenia. They administered ethinyl estradiol as an adjunct to haloperidol over 8 weeks and the control group received haloperi- dol only. The combination with estradiol showed a significant superiority over haloperidol alone regarding positive and negative symptom response. Furthermore, the estrogen group needed significantly less adjunctive anticholinergic medication to treat extrapyramidal side effects caused by haloperidol treatment. This finding is in line with other studies suggesting that estrogen treatment can also reduce the severity of antipsychotic medication-induced extrapyramidal side effects (Thompson et al. 2000). Louza et al. (2004) did not find a positive response to estrogen treatment in their study, which they correctly discussed as possibly being due to having used conju- gated estrogens rather than 17-b-estradiol. In a Cochrane review in 2005, Chua et al. (2005) surveyed data from only five randomized double-blind intervention studies with appropriate methodology. They concluded that the effects of estrogen as sole treatment or adjunctive therapy for those with schizophrenia and related psychoses were still unclear, but that further, larger clinical trials were needed. Studies in this review with negative results used conjugated estrogens and not 17-b- estradiol, although the latter has been shown to be the estrogen type with the most potent activity in the brain. Furthermore, to prevent endometrial hyperplasia, the estrogens were usually combined with progestogens which can counteract the positive effects of estradiol in the brain. Kulkarni (2009) recently conducted a proof-of-concept study of 102 women with DSM-IV schizophrenia. In this double-blind randomized controlled 28-day study, women received either an active 100 mg estradiol skin patch treatment (n ¼ 56) or an identical placebo patch (n ¼ 46). All patients received antipsychotic drug treatment according to a standardized protocol. Progesterone was not given during the study; hence, the trial measured the impact of unopposed estradiol. 162 A. Riecher-Rössler and J. Kulkarni Psychopathology was assessed using the PANSS rating scale. Serum levels of estrogen, progesterone, prolactin, luteinizing hormone, and follicle-stimulating hormone were measured. Several cognitive tests were also administered. They found that patients who received the 100 mg estradiol adjunct made a significantly better recovery in their total positive, negative, and general symptoms of schizo- phrenia than the patients who received standard antipsychotic medication only (p < 0.01). Women who received the estradiol patch also showed significant improvement in cognition (p < 0.01). By measuring luteinizing hormone, they could also demonstrate that there is a direct effect on the pituitary gland, which suggests that this dose and type of unconjugated estrogen directly affects the hypothalamic–pituitary–gonadal axis. Overall, these studies provide strong evidence for the estrogen protection hypothesis. The addition of transdermally delivered estradiol seems to be asso- ciated with significant abatement of psychotic symptoms in women with schizo- phrenia compared with standardized antipsychotic drug treatment alone. Most of the estrogen treatment studies conducted so far have been in young, reproductive age women and not in peri- or postmenopausal women with estrogen deficiency. Theoretically, the greatest effect of estradiol would be expected when it is replaced in a woman in a hypoestrogenic state. Good et al. (1999) conducted a study in postmenopausal patients. He administered estradiol and progesterone to 14 women with schizophrenia, schizophreniform disorder, or schizoaffective disorder and found a significant improvement of negative symptoms over 6 months. There are also some case reports regarding positive results of hormone replace- ment therapy (HRT) in postmenopausal women with schizophrenia and related psychoses. Bergemann et al. (2007b) reported a case study of a woman with first onset of schizophrenia in the perimenopause period. The patient experienced severe acute psychosis symptoms over several months, but refused antipsychotic treat-

ment. As she was diagnosed to be in a periclimacteric state based on clinical symptoms and hormone analysis, she was started on transdermal estradiol in combination with norethisterone acetate and had an impressive remission of the psychotic symptoms. Lindamer et al. (1997) reported details about a postmeno- pausal woman, whose psychotic symptoms improved with estradiol treatment as an adjunct to her antipsychotic. Lindamer et al. (2001) studied a community sample of postmenopausal women with schizophrenia and related psychoses. Twenty-four women received standard HRT, and 28 women had never received hormone treatment. Interestingly, the users of HRT needed a relatively lower average dose of antipsychotic medication and suffered fewer severe negative symptoms. Ahokas et al. (2000) described positive effects of estrogen treatment in women with postpartum psychosis. In those women who exhibited sustained estrogen deficiency states, the addition of 17-b-estradiol, without any further medication, yielded a dramatic antipsychotic effect within 1 week. However, the proportion of schizophrenia-like psychoses in the sample was not given. Finally, Kulkarni (2005) also tested the use of adjunctive estradiol in a small sample of 11 men with schizophrenia. They gave 2 mg oral estradiol valerate as an Estrogens and Gonadal Function in Schizophrenia and Related Psychoses 163 adjunct to six men who were taking antipsychotic drugs. Five men received oral placebo plus their standard antipsychotic medication for 7 days. This small study was only conducted for 7 days to avoid feminization and other side effects in the men. The groups were matched for age, illness severity, and duration. Oral, rather than transdermal, estradiol was used to ensure treatment adherence in men with acute psychosis. Psychopathology was assessed using the standardized rating scales, PANSS and the BPRS, Brief Psychiatric Rating Scale. By day 5, the estradiol group showed significant abatement of psychotic symptoms compared with the placebo group, and by day 7, the estradiol group made further improvements. This study, although small in sample size and short in duration, raises the possibility that nonfeminizing estrogen may provide useful treatment possibilities for men with schizophrenia. 3 Hypoestrogenism in Women with Schizophrenia (The Hypothesis of Hypoestrogenism) Several studies have recently confirmed earlier findings of disturbed gonadal function and hypoestrogenism in women with schizophrenia (Riecher-Rössler and Häfner 1993; Riecher-Rössler et al. 1994b, 1998; Choi et al. 2001; Kulkarni et al. 1996; Bergemann et al. 2002; Canuso et al. 2002; Hoff et al. 2001; Huber et al. 2001; Smith et al. 2002; Zhang-Wong and Seeman 2002). They described men- strual irregularities and reduced blood levels of estradiol, progesterone, and gona- dotropins (follicle-stimulating hormone, luteinizing hormone) throughout the menstrual cycle, plus anovulation in the majority of women with schizophrenia and related psychoses. Reduced fertility was also reported. There appear to be multiple reasons for these disturbances including the con- sequences of emotional stress and/or antipsychotic medication-induced hyperpro- lactinaemia, which is known to suppress gonadal function (Maguire 2002). However, these are probably not the only causes, because women experiencing other psychiatric disorders with similar emotional stress do not have the same hypothalamic–pituitary–gonadal axis hormone changes, at least not to the same degree (Riecher-Rössler et al. 1998; Huber et al. 2001). Furthermore, hypoestro- genism was observed long before the introduction of antipsychotics. Smith et al. (2002) found the dose of typical antipsychotics to correlate with prolactin levels especially in women and prolactin to correlate inversely with estradiol serum levels. In contrast to those findings, Huber et al. (2001) were unable to identify a significant association of prolactin and estradiol in 43 women with acute psychosis, 14 women with other diagnoses, and 9 healthy control women. Nevertheless, the women with schizophrenia and related psychoses had signifi- cantly lower estradiol serum levels than the control women. Women with other psychiatric diagnoses fell in between the psychotic and the healthy group with regard to estradiol and prolactin levels. Also, Canuso et al. (2002) found a high rate of ovarian dysfunction and estradiol levels below normal, irrespective of 164 A. Riecher-Rössler and J. Kulkarni medication type or prolactin status in 16 premenopausal women with schizophrenia and schizoaffective disorders. Interestingly, Warner et al. (2001) found prolactin levels in unmedicated schizophrenic patients to be even lower than in control individuals. Those investigators suggested that this was due to a disordered dopa- minergic system because dopamine tonically inhibits prolactin. Taken together, these results imply that the hypothalamic–pituitary–gonadal axis is disturbed in many women with schizophrenia and related psychoses, and that the reasons for this are far from clear yet. An interesting research question in this context is whether gonadal dysfunction with estrogen deficiency could even be part of the underlying pathogenetic process, at least in a subgroup of women (Riecher-Rössler 2002). 4 Implications for Clinicians and Researchers Further research into the impact of gonadal function and estrogen on schizophrenia and related psychoses is warranted because new diagnostic and therapeutic strate- gies could emerge that would benefit the many women worldwide who suffer from this disorder. 4.1 Assessment and Therapy of Gonadal Dysfunction As there is growing evidence that many, even younger women, with schizophrenia and related psychoses are in a state of estrogen deficiency, in future estrogens and the gonadal axis should be considered more seriously in the treatment of women with schizophrenia and related psychoses. Psychiatric history taking should always include questions regarding menstrual irregularities, amenorrhoea, and galactor- rhoea. Also, prolactin and estrogen serum levels should be tested, if necessary. Gonadal dysfunction and hypoestrogenic states can often be found even in men- struating women (Riecher-Rössler et al. 1994b, 1998; Smith et al. 2002). In addition, hyperprolactinaemia is clearly underdiagnosed (Maguire 2002). Some authors have therefore suggested routine laboratory tests (Smith et al. 2002). Most antipsychotics can cause hyperprolactinaemia and – especially if they are taken over a number of years – theoretically induce “iatrogenic early menopause” via suppression of physiological estradiol production. The concomitant risks include both short-term effects, such as hot flushes and sexual dysfunction, and long-term consequences, including osteoporosis and potentially cardiovascular disease or cognitive deterioration (Oesterlund 2002; Maguire 2002). In schizophrenia patients, these risks are further increased by additional risk factors such as smoking, poor diet, and reduced exercise (Smith et al. 2002). Furthermore, menopausal complaints may lead to compliance problems. In the case of hyperprolactinaemia with secondary estrogen deficiency, prolactin- sparing antipsychotics (e.g., clozapine, quetiapine, aripiprazole, or maybe olanzapine; Estrogens and Gonadal Function in Schizophrenia and Related Psychoses 165 Maguire 2002) should therefore be preferred. If a switch to these antipsychotics is not possible for clinical reasons or if hypoestrogenism persists despite switching, then estrogen can be added to the treatment. Issues regarding contraception must be taken into account in such cases because, when switching to prolactin-sparing antipsycho- tics, the menstrual cycle often normalizes and fertility is regained, with high risk for unplanned pregnancy (Neumann and Frasch 2001). 4.2 Estradiol as a Therapeutic Agent? First trials of estrogens in schizophrenia and related psychoses indicate that estra- diol could be used as an adjunct to antipsychotic medication. However, further replications of these findings in larger control studies by different groups are needed before recommendations for broad clinical application can be made. In women who suffer from frequent perimenstrual psychotic relapses, “cycle modulated” antipsychotic medication therapy or, if contraception is needed at the same time, continuous use of oral contraceptives without hormone-free intervals may be strategies worthy of research (Riecher-Rössler 2002; Braendle et al. 2001). Even more promising could be hormonal replacement with estrogens in women with schizophrenia in peri- and postmenopause, because estrogens in other disor- ders such as depression have proven to be especially helpful when they are used to restore hormonal balance. Hormonal replacement with estrogens for women with schizophrenia during and after the perimenopause could be recommended as an augmentation strategy respectively an adjunct to antipsychotic medication. Possibly, the dose of antipsy- chotics could then be reduced and corresponding side effects minimized. The replacement of estrogens in these women could also attenuate perimenopausal complaints such as hot flushes, night sweats with sleep disturbances, and general irritability (see Table 1), which can contribute to a general deterioration of the mental state and, in vulnerable women, potentially provoke a psychotic episode. In contrast to this recommendation, it has been reported that women with schizophrenia are less likely to ever use HRT as compared to women without psychiatric diag- noses (Lindamer et al. 2003). Estrogen replacement therapy for women of this age group has been recom- mended anyway for many reasons, for example prophylaxis of osteoporosis, and also delay of age-dependent cognitive deterioration or Alzheimer’s dementia (Sherwin 2005) (for review, see Riecher-Rössler and de Geyter 2007; Table 1). Further research into estrogen treatment as an additional indication in peri- and postmeno-pausal women schizophrenia and related psychoses is urgently needed. The use of estrogen has been questioned in the context of perimenopausal estrogen replacement by studies such as the WHI, Women’s Health Initiative Study (Rossouw et al. 2002), the WHI-M, Women’s Health Initiative Memory Study (Craig et al. 2005), and the HERS, Heart and Estrogen/Progestin Replace- ment Study (Hlatky et al. 2002). These studies have highlighted the side effects of 166 A. Riecher-Rössler and J. Kulkarni Table 1 Some important effects of estrogen replacement Positive Negative Perimenopausal complaints # Endometrial carcinoma " if unopposed estrogens Physical: hot flushes, genital discomfort, aging are administered (! in women without of collagen (skin, joints, intervertebral hysterectomy always combine with discs) # progestogens!) Mental: depression, irritability, emotional lability # Risk of osteoporosis # Risk of breast cancer "? (! do not use in patients with a familiar or own risk of breast cancer and usually not longer than 7 years!) Delay of cognitive decline/Morbus Alzheimer? Risk of thrombosis and cerebral insult "? (! no prescription for patients at risk!) Cardiovascular protection? (if started right after Other cardiovascular risks (coronary heart menopause) disease, arteriosclerosis) "? (! start only within the first 10 years after menopause and not in patients with cardiovascular disease!) Sources: Riecher-Rössler and de Geyter (2007), Birkhäuser et al. (2008), Rossouw et al. (2007) HRT, which has provoked an ongoing controversy about the advantages and disadvantages of this regime. However, the WHI study has been criticized by many experts and by the International Menopause Society (Birkhäuser et al. 2008) because of the advanced age of the study population (mean age at inclusion was 63 years) who had a high prevalence of cardiovascular risk factors. Many of the complications noted for participants in the WHI study such as stroke, pulmonary embolism, and myocardial infarction, which were attributed to the vascular effects of estrogens, could well have been due to pre-existing arteriosclerosis. The WHI conclusions have now been partially counteracted by a reanalysis (Rossouw et al. 2007), which showed that the cardiovascular complications can be reduced using replacement therapy early in the perimenopause. This has opened a window of opportunity in which possibly even a cardiovascular benefit can be obtained in healthy menopausal women when replacement therapy is started early after the menopause (for review, see Riecher-Rössler and de Geyter 2007). Overall, the use of estrogens for therapeutic reasons must be distinguished from their preventative use. The WHI investigated the latter use and as described above, concerns about the conclusions have been made. The potential therapeutic use in women with psychosis or other mental disorders has been discussed here, and while care must be given to monitoring potential side effects, the benefits for women with poor quality of life due to intractable schizophrenia often outweigh the risk of side effects. Further research needs to be done into the best mode of HRT for psychiatric patients. To date, the natural 17-b-estradiol has been shown to have the best neuropsychoprotective effects compared with other estrogens that are often pre- scribed. Transdermal application in the form of patches or gel is preferred because of smoother metabolism and potentially fewer side effects. Progestogens are usu- ally added to estrogens to prevent endometrial cancer, but they can antagonize the Estrogens and Gonadal Function in Schizophrenia and Related Psychoses 167 positive effects of estrogens with respect to mental state (Cyr et al. 2002; Braendle et al. 2001). These systemic effects of progestogens should be minimized by careful selection of the progestogen, and also, potentially by other forms of application. Furthermore, alternatives to conventional HRT, i.e., compounds with more specific and potent estrogenic activity in the brain as opposed to other tissues, need to be investigated (Riecher-Rössler 2002;

Halbreich 2002). Such compounds would both minimize the side effects of hormonal therapy and permit new thera- peutic strategies in men. Possible candidates are selective estrogen receptor mo- dulators, which have agonistic or antagonistic properties that depend on the target tissue. However, the effects of the available selective estrogen receptor modulators on the brain remain to be clarified. Raloxifene, for example, appears to exert its main effects on the bone, although recent data suggest that it also acts on different brain receptors (Craig et al. 2005). A recent study by Kulkarni et al. has shown promising antipsychotic effects for adjunctive raloxifene in postmenopausal women with schizophrenia (Kulkarni et al. 2010). Also, the synthetic steroid tibolone appears to cause less endometrial proliferation, but its effects on the central nervous system are still not clear, apart from the fact that it appears to have an androgenic effect and increases b-endorphin levels, with improvement in mood and libido (Davis 2002). Further studies on the brain-specific effects of selective estrogen receptor modulators and other estrogenic compounds (e.g., phyto-estro- gens, xeno-estrogens, and dihydroepiandrosterone) are urgently needed. 5 Summary and Conclusions In summary, there is emerging evidence that estrogens are very useful neuropro- tective and psychoprotective adjunctive therapies, which could complement and enhance the traditional drug therapies for people with schizophrenia and related psychoses. However, it must be emphasized that the role for estrogen treatment strategies still requires further research. In particular, results from larger, well- controlled studies are needed before estrogens may be recommended as adjunct therapy in standard clinical practice for the treatment of women with schizophrenia, without proven estrogen deficiency. In contrast, other strategies should already be part of standard clinical care (Grigoriadis and Seeman 2002). These include examination of the gonadal axis, with therapeutic actions, if indicated. In peri- and postmenopause HRT can be used, but the decision to use estrogen replacement therapy must always be made on the basis of an individual risk–benefit assessment (Brikhäuser et al. 2008) and in close collaboration with a gynecologist. For future research, many questions remain unresolved, regarding not only new therapeutic strategies and compounds but also the poorly understood disturbances of estrogens and the hypothalamic–pituitary–gonadal axis in women with schizo- phrenia and related psychoses. 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62:225–6 Thompson KN, Kulkarni J, Sergejew AA (2000) Extrapyramidal symptoms and oestrogen. Acta Psychiatr Scand 101:130–4 Vedder H, Behl C (2005) Estrogens in neuropsychiatric disorders: from physiology to pathophysi- ology. In: Bergemann N, Riecher-Rössler A (eds) Estrogen effects in psychiatric disorders. Springer, Wien, pp 1–30 von Zerssen D, Koeller D (1976) Klinische Selbstbeurteilungs-Skalen (KSb-Si) aus demMünchener Psychiatrischen Informations-System (PSYCHIS München). Manual. Beltz, Weinheim Warner MD, Walker AM, D’Souza DC, Lee D, Nasseri D, Peabody CA (2001) Lower prolactin bioactivity in unmedicated schizophrenic patients. Psychiatry Res 102:249–54 Weickert CS, Miranda-Angulo AL, Wong J, Perlman WR, Ward SE, Radhakrishna V et al (2008) Variants in the estrogen receptor alpha gene and its mRNA contribute to risk for schizophrenia. Hum Mol Genet 17:2293–309 Yonkers KA, Kando JC, Cole JO, Blumenthal S (1992) Gender differences in pharmacokinetics and pharmacodynamics of psychotropic medication. Am J Psychiatry 149:587–95 Zhang-Wong JH, Seeman MV (2002) Antipsychotic drugs, menstrual regularity and osteoporosis risk. Arch Womens Ment Health 5:93–8 . Oestradiol and Psychosis: Clinical Findings and Biological Mechanisms Angelika Wieck Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 2 Clinical Studies That Link Oestradiol with Schizophrenia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 3 Clinical Studies That Link Oestradiol with Bipolar Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 4 Oestradiol in the Brain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 5 Mechanisms That May Mediate Oestradiol Effects in Schizophrenia . . . . . . . . . . . . . . . . . . . . 177 6 Mechanisms That May Mediate Oestradiol Effects in Bipolar Disorder . . . . . . . . . . . . . . . . . . 178 7 Treatment Studies in Schizophrenia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 8 Treatment Studies in Bipolar Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 9 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 Abstract Female sex steroids easily access the central nervous system and modu- late a number of intracerebral processes via their specific receptors. Oestradiol is the biologically dominant female sex steroid and has been implicated in the aetiology and course of psychotic illnesses. There is evidence for interaction between oestradiol and several neurobiological systems that have been implicated in the pathogenesis of psychotic illnesses. Clinical studies have indicated that psychosis, and in particular schizophrenia, is associated with reduced ovarian function and that this may be inherent to the illness itself. In schizophrenia several studies have suggested a therapeutic effect of oestradiol and selective oestrogen modulators although research is still at an early stage. In bipolar disorder, the relationship between childbirth and first onsets or recurrences is one of the most reproducible findings in psychiatric research. Whether or not the rapid fall of oestrogens is the mediating mechanism is not yet clear but preliminary oestrogen treatment studies commenced immediately after childbirth are promising. Outside the perinatal context, tamoxifen, a selective oestrogen receptor modulator, has A. Wieck Laureate House, Wythenshawe Hospital, Manchester Mental Health and Social Care Trust, University of Manchester, Southmoor Road, Manchester M239LT, UK e-mail: angelika.wieck@manchester.ac.uk J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 173 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2011_127, # Springer‐Verlag Berlin Heidelberg 2011, published online 10 May 2011 174 A. Wieck shown strong antimanic effects although further studies are necessary to test an effect in larger samples. Hormonal treatments should not yet be used in standard care but could be considered in women with treatment resistant psychoses. Keywords Bipolar
Mechanism
Oestrogen
Oestradiol
Psychosis
SERM
Schizophrenia
Treatment 1 Introduction Research into the biological mechanisms that mediate gender differences in psy- chosis and the influence of reproductive events on the course of psychosis in women has focussed on female sex steroids, and particularly oestradiol as the predominant ovarian steroid. In this chapter, the relationships between oestradiol, ovarian func- tion and the course of the two major psychoses, namely schizophrenia and bipolar disorder, the biological mechanisms that may be involved and recent treatment trials that have used oestrogens and oestrogen receptor modulators will be discussed. 2 Clinical Studies That Link Oestradiol with Schizophrenia There are several lines of evidence that link oestrogen with the course and severity of schizophrenia. In epidemiological studies, the age of illness onset has consis- tently been shown to be 4–6 years later than in men (Lewine 1988; H€afner et al. 1991; Castle and Murray 1991). This applies not only to the first sign, first negative symptom, first positive symptoms, and first full episode, but also to the first admission (H€afner 2003). Women have also been reported to have a second peak of onset in the perimenopause (H€afner 2003). Several recent studies have reported that female inpatients and outpatients with schizophrenia tend to have hormonal profiles consistent with insufficient maturation of ovarian follicles and anovulatory cycles, even during treatment with prolactin-sparing antipsychotic medication (Riecher-Roessler et al. 1994; Huber et al. 2001; Canuso et al. 2002; Bergemann et al. 2005). This indicates a hypotha- lamic–pituitary dysfunction or a reduced ovarian sensitivity to pituitary peptide stimulation. However, alternative explanations for an impaired ovarian activity such as weight gain (Brewer and Balen 2010) induced by psychotropic medication and stress (Genazzani et al. 2010) on ovarian activity have not been ruled out. Despite the low oestradiol levels in schizophrenia, their fluctuations have neverthe- less been shown to influence symptom severity. Riecher-Roessler et al. (1994) investigated 32 women, who were admitted for the treatment of an acute psychotic exacerbation and were on antipsychotic medication. In the weeks subsequent to admission, measures of overall illness severity, thought disturbance and paranoia Oestradiol and Psychosis: Clinical Findings and Biological Mechanisms 175 inversely correlated with oestradiol levels. Furthermore, Seeman (1983) described that women ageing between 20 and 40 years require lower antipsychotic doses than older women or men and suggested that oestrogen may have anti-dopaminergic action. In line with this observation, Gattaz et al. (1994) showed a significant inverse association between oestradiol plasma concentrations and the required dose of antipsychotic medication. Childbirth is the reproductive event that is associated with the largest changes in female sex steroid production. During pregnancy, oestradiol and progesterone serum concentrations gradually increase and reach values at term that are 100–200 times higher than in the early follicular phase of the menstrual cycle. Immediately following the expulsion of the placenta, levels begin to decline rapidly and reach follicular phase levels within 2–3 days. It has been known for some time that childbirth can trigger psychotic illnesses, but two recent epidemiological studies covering the whole population of Denmark over three decades have quanti- fied this effect for different diagnoses more precisely (Munk-Olsen et al. 2006, 2009). In these studies, inpatient admissions for first onsets and recurrences of schizophrenia were 2–5.7 times more common in the 2 months after childbirth than later in the first postnatal year. Based on these several strands of evidence, it has been suggested that oestrogen protects women from an early onset and severe course of illness, but that this advantage is lost in the perimenopause when oestrogen production declines (H€afner et al. 1989; Seeman and Lang 1990). These findings also suggest that women with schizophrenia may benefit from treatment with oestradiol to enhance this effect and that the dose required may not be large. 3 Clinical Studies That Link Oestradiol with Bipolar Disorder There are no findings of a gender difference in the age of onset in bipolar disorder. However, one of the most remarkable findings in psychiatry is the powerful relationship of this illness with childbirth. In the studies by Munk-Olsen et al. (2006, 2009), the risk of a first or subsequent inpatient admission for bipolar disorder was increased more than 20 times in the first month after childbirth. Based on the dopamine hypothesis of bipolar disorder, Cookson (1982) suggested that bipolar episodes in the puerperium may be triggered by the rapid and massive decline of oestrogen or progesterone after childbirth via its effect on the dopami- nergic system (Cookson 1982). Whether the fall of sex steroid concentrations at the end of the menstrual cycle is associated with a worsening of bipolar symptoms is controversial. Two early retrospective studies found greater affective symptomatology in the premenstrual phase in women with bipolar disorder than healthy controls (Diamond et al. 1976; Price and DiMarzio 1986). However, in a cross-sectional interview study of women with recurrent major depressive disorder (N ¼ 509) and bipolar 1 disorder (N ¼ 197), Payne et al. (2007) found significant associations between histories of 176 A. Wieck postpartum affective symptoms and premenstrual or perimenopausal mood changes in the major depression group (odds ratios 1.82 and 1.66) but not in the bipolar group. Karadag et al. (2004) prospectively followed 34 stable medicated patients with bipolar disorder and 35 healthy controls. Participants kept daily records of their mental and physical wellbeing over 2 months and completed an interview on their experiences across menstrual cycles. The bipolar group complained less often about mood changes, such as mood lability, depressive symptoms, and anger and irritability than the control group. In two prospective studies of rapid cycling bipolar patients, there were also no significant effects of the premenstrual cycle phase on bipolar mood changes (Wehr et al. 1988; Leibenluft et al. 1999). There are two reasons why these studies are difficult to interpret. First, bipolar patients in these studies were on mood stabilizing medication, which may have suppressed premenstrual affective symptoms. Second, several authors commented on the high rate of menstrual cycle abnormalities in the bipolar subjects, and this may mean that their endocrine states across menstrual cycles were different from the controls. As in womenwith schizophrenia, several explanations need to be

considered for such ovarian dysfunction. These include antipsychotic-induced hyperprolactinae- mia (Wieck and Haddad 2003), valproate-induced polycystic ovarian syndrome (Joffe et al. 2006) or a dysregulation of the hypothalamic–pituitary– ovarian axis inherent in bipolar disorder. Rasgon et al. (2005) found that half of their 80 female study partici- pants with bipolar disorder reported on interview that they had menstrual irregularities before commencing anti-bipolar medication. Similarly, in the Harvard Study of Moods and Cycles, Joffe et al. (2006) found that significantly more women with bipolar disorder reported early-onset menstrual cycle dysfunction (34.2%, before the onset of their illness) than healthy controls (21.7%). Brockington (2005) reviewed the world literature on bipolar-like psychoses that repeatedly recur at the same phase of the menstrual cycle. However, this phenome- non has mostly been described in case reports or case series and does not appear to occur commonly. 4 Oestradiol in the Brain About 1–3% of the total plasma oestrogen and progesterone circulate in serum unbound to proteins (Wu et al. 1976; Darne et al. 1987; Meulenberg and Hofman 1989) and are free to enter the brain by diffusion. The concentration of total oestradiol and progesterone in CSF correlates strongly and significantly with that in plasma (B€ackstr€om et al. 1976), and the free fraction in plasma is of about the same magnitude as the total hormone in cerebrospinal fluid (Schwarz and Pohl 1992). On the other hand, CSF levels of the sex steroid-binding proteins (albumin, steroid hormone-binding globulin and cortisol-binding globulin) are several hun- dred times lower than in serum, suggesting that most of the total oestrogen and progesterone in CSF are free (Schwarz and Pohl 1992). Oestradiol and Psychosis: Clinical Findings and Biological Mechanisms 177 Oestrogens have a broad spectrum of actions in the central nervous system, which are mediated either via rapid alteration in signal transduction via membrane receptors or by slower modulation of gene transcription via receptors located intracellularly (Marshall 2011). Two oestrogen receptor subtypes, alpha and beta, have been identified, and their genes are located on different chromosomes. In the human forebrain, both subtypes are predominantly expressed in limbic-related areas although their distribution patterns differ (see review by Hughes et al. 2009). The mRNA expression of the alpha receptor appears to dominate in the hypothalamus and amygdala, areas concerned with autonomic and reproductive neuroendocrine functions as well as emotion interpretation and processing, whereas the beta isoform is dominant in the hippocampal formation, the entorhinal cortex and the thalamus, suggesting a possible role in cognition, non-emotional memory and motor functions (Hughes et al. 2009). 5 Mechanisms That May Mediate Oestradiol Effects in Schizophrenia Oestrogen effects on the function of themesolimbic andmesocortical dopaminergic and hippocampal glutamatergic systems are particularly relevant to psychoses. It is clear that dopaminergic neurones have oestrogen receptors (Creutz and Kritzer 2002), and that oestrogen interacts with dopaminergic systems (Sánchez et al. 2010). However, there is substantial variability in the direction of effects, reflecting differences in dose, duration of treatment, experimental protocols and outcomes studied (Chavez et al. 2010; Sánchez et al. 2010). An experimental tool that has been widely used in the exploration of neurobiologi- cal mechanisms in schizophrenia is prepulse inhibition (PPI); see chapter by Veena Kumari (2011) for more details. This is the reduction of a startle response to a sudden loud noise if it is preceded by a weak prepulse within 30–500 ms. The inhibition of this reflex is modulated by brain circuits linking the limbic cortex, striatum, pallidum and pontine tegmentum and higher brain structures, such as the prefrontal cortex and hippocampus (Swerdlow et al. 1997), so that sensory information can be filtered and attention focussed. PPI is reduced in schizophrenia, some other psychiatric and several neurological disorders (Braff et al. 2001). A reduction in PPI during treatment with dopamine agonists and a reversal by antipsychotic agents in rodents suggest a contribution of the dopamine system in the modulation of PPI (Zhang et al. 2007; Mansbach et al. 1988) In schizophrenic patients, the PPI deficit may also be reversed by atypical antipsychotic treatment (Wynn et al. 2007; Aggernaes et al. 2010). Furthermore, recent studies suggest that dopaminergic modulation of PPI can be influenced by the hormonal milieu. For example, in female ovariectomized rats, high dose oestrogen treatment over 2 weeks has been shown to prevent apomorphine- induced disruptions of PPI, and that this may be mediated via an action on dopamine D2 receptors (Gogos et al. 2010). In healthy women, variations in sex steroid levels are also accompanied by changes in PPI. A greater PPI has been observed during the 178 A. Wieck follicular phase relative to the luteal phase of the menstrual cycle (Swerdlow et al. 1997; Jovanovic et al. 2004). However, Kumari et al. (2010) did not find a correlation between changes in PPI and oestradiol levels between menstrual cycle phases but reported that a greater progesterone increase in the luteal phase was associated with a greater protection of PPI. The relationships between physiological changes in female steroid production, dopaminergic function and PPI have not yet been inves- tigated in human females with or without schizophrenia. However, the usefulness of PPI as a model for neural processes operating in schizophrenia is limited, since PPI decreases are neither specific for schizophrenia nor do they predict the pattern of symptoms, the course of illness or individual treatment responses (Swerdlow et al. 2008). Although research of neurotransmitter function in schizophrenia focussed for many years on excess dopaminergic function in the striatum, more recently it has been suggested that this is secondary to dysfunctional glutamatergic neurotrans- mission (Carlsson et al. 2001), a hypothesis that has recently been confirmed by Stone et al. (2010). In this imaging study of drug-free subjects at very high risk of schizophrenia, the authors found a negative correlation between glutamate levels in the hippocampus and striatal dopaminergic activity. Preliminary evidence indi- cates that oestradiol can modulate glutamatergic function in the hippocampus and other brain regions (Smejkalova and Woolley 2010; Grove-Strawser et al. 2010). Whether this interaction is relevant to schizophrenia requires further research in preclinical and human studies. 6 Mechanisms That May Mediate Oestradiol Effects in Bipolar Disorder Although effective treatments are available for bipolar disorder, a comprehensive pathophysiological model of the illness is still lacking (Cousins et al. 2009). In their review of the role of dopamine in bipolar disorder, Cousins et al. (2009) conclude that this neurotransmitter system is likely to play a central role in the understanding of the pathophysiology of this illness. They also suggested that it may be the second messenger systems and downstream pathways that are directly involved rather than presynaptic processes or postsynaptic dopamine receptors. Overactivity of one element in the dopamine signal transduction pathway, protein kinase C, has been associated with acute mania and several known antimanic agents, such as lithium, valproate, carbamazepine, aripiprazole and quetiapine, inhibit it (reviews by Zarate and Manji 2009; Cousins et al. 2009). Recent studies have also shown that the selective oestrogen receptor modulator tamoxifen is a centrally active protein kinase C inhibitor and has therefore been tested as an antimanic agent. There are to date only two biological studies in humans that investigated biological mechanisms that might be involved in the triggering effect of child- birth on bipolar recurrences. To test the hypothesis that they are triggered by the Oestradiol and Psychosis: Clinical Findings and Biological Mechanisms 179 effects of oestrogen withdrawal on the dopaminergic system, the apomorphine- induced growth hormone response was used as a measure of neurotransmission via hypothalamic D2 receptors. In the first study (Wieck et al. 1991), 15 drug- free women who had a history of bipolar illness but were currently well and 15 control women with no psychiatric history were recruited in late pregnancy. The neuroendocrine test was carried out on day 4 after delivery, and those who subsequently had a recurrence had a significantly higher response than those who remained well. However, the stimulation of hypothalamic growth hormone secretion is relatively blunted in the early postnatal period, and the study may have underestimated differences in the neuroendocrine response between the women who relapsed and those who did not. In the second study, hypothalamic D2 receptor sensitivity was tested across the menstrual cycle in eight medica- tion-free well women with a history of puerperal bipolar illness and normal menstrual cycles and nine normally menstruating controls (Wieck et al. 2003). Subjects underwent the same apomorphine growth hormone test in the early follicular phase when oestrogen levels are low and in the midluteal phase when oestradiol levels are enhanced. The midluteal time point was defined as 7–11 days after the pre-ovulatory LH surge which was determined by ovulation test kits. Although the women with bipolar disorder were currently well, they had an enhanced response to apomorphine in the midluteal phase. This indicates that the hypothalamic dopaminergic system of women predisposed to puerperal bipolar illness responds more sensitively to changes in oestradiol levels. In view of recent findings, it is possible that this hypersensitivity is related to a dysfunction in the intracellular signalling system rather than the D2 receptors themselves. It is uncertain, however, whether such hypothalamic effects are representative of regulatory processes in the mesolimbic or mesocortical dopamine systems. 7 Treatment Studies in Schizophrenia Chua et al. (2005) conducted a systematic review of oestrogen treatment trials in schizophrenia or related non-affective psychoses. They identified five rando- mized placebo-controlled studies including a total of 122 patients. Oestrogen treatments were adjunctive to antipsychotic therapy and lasted between 3 weeks and 6 months. No significant effect of active treatment was found on psychopathol- ogy. However, the authors concluded that the existing literature was difficult to interpret on account of the small sample sizes, randomization issues and the differ- ences between studies in respect of menopausal status, phase of illness, type of oestrogen used, routes of administration and dose. A large double-blind randomized placebo-controlled trial (N ¼ 102) of transdermal oestradiol treatment (100 mg over 24 h) over 28 days as adjunct to antipsychotic medication was published by Kulkarni et al. (2008). Participants were inpatients or outpatients, had a diagnosis of schizo- phrenia, schizophreniform disorder or schizoaffective depression and were in the acute or chronic phase of illness. At baseline, the mean score on the Positive and 180 A. Wieck Negative Symptoms Scale (PANSS) was similar to that reported by the authors of the scale for their sample of inpatients with schizophrenia (Kay et al. 1989). There were no differences between the groups in regard to adverse oestrogen-related or motor side effects. However, there were significant improvements in the active treatment group for the total PANSS score (p < 0.002), the positive symptom subscale (p < 0.005) and the general psychopathology subscale (p < 0.01), but not the negative symptom subscale. This pattern of response is often seen in trials of antipsychotic medication. The transdermal application of 17-b oestradiol has the advantage of avoiding first pass liver metabolism. However, oestrogen treatment has several drawbacks. Its long-term effects in premenopausal women is not known, and in postmeno- pausal women it increases the risk of endometrial and breast cancer as well as myocardial infarct and stroke. Raloxifene is a promising alternative to 17-b oes- tradiol since it is an antagonist at the breast and does not promote endometrial cancer. However, it has been associated with a small increase in the risk of venous thromboembolism (Nelson et al. 2009). While the amounts entering the brain are reported to be small, pharmacological CNS effects have nevertheless been reported in animals (Littleton-Kearney et al. 2002) as well as in postmenopausal women (Neele et al. 2001). Treatment with raloxifene was piloted in a dose-finding randomized controlled trial by Kulkarni et al. (2010) in 35 postmenopausal women in the acute phase of schizophreniform or schizoaffective disorder. Participants allocated to either 60 or 120 mg of raloxifene or placebo as adjuncts to antipsychotic medication over 12 weeks. Despite the small sample size, at the end of treatment there was a significant decrease in the total PANSS score (p < 0.001) and the general symptom score (p < 0.02) in the group treated with the larger dose. 8 Treatment Studies in Bipolar Disorder Despite the high risk of bipolar recurrences in the immediate postpartum period, only few investigators have attempted testing the preventative or acute efficacy of pharmacological interventions. Due to ethical constraints, randomized controlled studies cannot be conducted

in late pregnancy and large-scale observational natu- ralistic studies are logistically difficult, due to the relatively low number of patients at risk in the catchment areas of individual hospitals. Such studies require the collaboration of specialists in perinatal psychiatry from several centres. Two open uncontrolled studies have prospectively tested the effect of oestrogen treatment commenced after delivery. The rationale was to soften the impact of the rapid decline of oestrogen levels following the expulsion of the placenta. Sichel et al. (1995) administered conjugated equine oestrogens to 11 drug-free women with histories of predominantly puerperal psychosis which is thought to be closely related to bipolar disorder. Oestrogens were administered immediately Oestradiol and Psychosis: Clinical Findings and Biological Mechanisms 181 after childbirth at a high dose (eight times the maximum postmenopausal dose) with heparin protection, and the dose was gradually stepped down. Only one woman relapsed. This contrasts with the reported rates of postnatal recurrences of 26–57% in groups of women with a history of bipolar/schizoaffective disorder irrespective of their medication status (Reich and Winokur 1970; Dean et al. 1989; Robling et al. 2000; Jones and Craddock 2001; Robertson et al. 2005) and rates of 40% and 70%, respectively, in two medication-free samples (Marks et al. 1991; Viguera et al. 2000). In a dose-finding study of 29 drug-free women with histories of bipolar or schizoaffective disorder, transdermal patch treatment delivering 200, 400 and 800 mg oestradiol per 24 h was commenced within 48 h under heparin protection and stepped down over 12 days (Kumar et al. 2003). All women were admitted for at least the duration of the trial. The recurrence rate was not lower than expected (41%), but the highest starting dose (equivalent to 16 times the postmen- opausal dose) was associated with a significantly shorter duration of admission than the two lower doses. It is possible that the difference between the two studies is due to the timing of the first dose. In the second study, treatment may have been initiated too late since the decline in oestradiol and progesterone is immediate and rapid after the expulsion of the placenta. However, due to the concern over postpartum thrombosis as well as postpartum bleeding during protective heparin treatment, the risks of commencing treatment immediately after childbirth could be too high to pursue this approach further. In an open uncontrolled trial, ten women with established and severe puerperal psychosis were treated with oestradiol for 6 weeks (Ahokas et al. 2000). The term “puerperal psychosis” is often used in clinical practice to denote the proximity to childbirth without specifying the type of psychosis. Because a large proportion of these illnesses are on the bipolar spectrum, the study was included here. Participants had an illness onset on day 12 on average and entered the study at a mean of 12 weeks postpartum. Four patients had been treated unsuccessfully with antipsychotic medication before the trial. Oestradiol was administered sublingually to avoid first pass metabolism by the liver. None of the women had menstruated since delivery, and oestradiol levels were very low at baseline. The daily oestradiol dose was titrated according to serum concentrations with the aim of reaching concentrations of 400 pmol/L, i.e., about one-third of the peak level during the regular menstrual cycle. The score of the Brief Psychiatric Rating Scale fell dramatically within the first week from 78.3 to 18.8 (p < 0.001), and by week 2 the patients had become almost symptom-free. One woman discontinued oestradiol by week 5 and had a full recurrence of symptoms in week 6. Recently, several studies have tested the antimanic properties of the selective oestrogen receptor modulator tamoxifen in male and female patients with bipolar disorder. In a single blind study, tamoxifen up to 80 mg daily lead to a rapid improvement in five of seven patients with mania (Bebchuk et al. 2000). In another small, 4-week, double-blind, placebo-controlled, add-on study, treatment with 40 mg tamoxifen (n ¼ 5), medroxyprogesterone acetate (n ¼ 4) and placebo (n ¼ 4) was compared (Kulkarni et al. 2006). Subjects in the tamoxifen group had a significantly greater decrease in manic and positive psychotic symptoms 182 A. Wieck compared to the placebo group (p < 0.05). All patients were receiving concomitant medication with either lithium or valproate. Similar results were obtained in two subsequent 3-week double-blind placebo-controlled, monotherapy studies. The study by Zarate et al. (2007) tested higher doses of up to 140 mg/day in a sample of 16 patients, and ratings were obtained daily during the first week. Significant improvements were seen as early as day 5, and the difference to placebo remained significant up to the end of treatment (p < 0.001) with a large effect size (d ¼ 1.08). In the largest study (N ¼ 66), Yildiz et al. (2008) used doses of up to 80 mg/day over 3 weeks. Significant improvement in the ratings of mania and clinical global impres- sion (both p < 0.001) was reported at the end of treatment. In a fifth study (Amrollahi et al. 2011), tamoxifen or placebo were randomly added to treatment with lithium in 40 patients with acute mania. A significantly greater improvement was apparent at week 1 in the active treatment group, and this difference continued until the end of treatment in week 6. The sample sizes in these trials are small, but the results are consistent and suggest that tamoxifen may be an effective antimanic agent that is well tolerated and acts rapidly. Drawbacks of the treatment are an increased risk of thrombo- embolic events and endometrial cancer. It may therefore be more suitable for short-term treatment of severe or treatment-resistant acute mania, particu- larly in men. Although tamoxifen belongs to the group of selective oestradiol receptor mod- ulators, it is thought that it involves a direct action on protein kinase C rather than the oestrogen receptor (O’Brian et al. 1986). 9 Conclusion Insights into the various aspects of the relationship between oestradiol and psy- chotic illness are still limited. Although there is considerable evidence for a role of oestradiol, particularly for schizophrenia, not all available research supports this. Nevertheless, in a recent well-designed randomized controlled treatment trial, women with acute schizophrenia-like illnesses responded well to the use of transder- mal oestradiol (Kulkarni et al. 2008). The oestradiol dose of 100 mg/24 h is relatively low for a premenopausal patient group, since it only achieves levels that are similar to the early follicular phase of the menstrual cycle (Chetkowski et al. 1986). The mechanism by which the improvement was mediated is also not clear as yet. At the beginning of treatment, the patients were in different endocrine states. About one- third of the patients were taking antipsychotic medication with prolactin-elevating potential, and others entered the study in different phases of the menstrual cycle. The pattern of oestradiol levels across the 4 weeks of treatment that resulted from the interactions of endogenous hormone production, transdermally applied hormone and its potential to disrupt ovulation is difficult to predict. The mean oestradiol serum levels were low at baseline before treatment was begun (71.0 pg/ml). Potential mechanisms that could explain a therapeutic effect include that oestradiol levels Oestradiol and Psychosis: Clinical Findings and Biological Mechanisms 183 stayed above a certain critical level or that the treatment led to less fluctuations over the treatment period than would have otherwise occurred. Further clinical trials by different research groups that examine pituitary gonadal peptide and female sex steroid secretion during treatment are required to test this promising treatment further. Preliminary data on the therapeutic efficacy of raloxifene are also encourag- ing, particularly because it has a less adverse side-effect profile. Further preclinical research is required as to its actions in the central nervous system. In bipolar disorder, it is not clear whether there is a pre-existing immaturity in the hypothalamic–pituitary–ovarian axis, and future studies should clarify this important point. The strong relationship of bipolar disorder with childbirth is a much replicated finding, and the predominant hypothesis has been that the postpartum oestrogen withdrawal triggers a latent dopaminergic dysfunction. There is some indirect evi- dence to support this view. There is also uncontrolled evidence that oestradiol treatment may be useful in the treatment of puerperal bipolar or affective psychotic episodes although it may only be worth pursuing this treatment in established illness rather than in prevention due to the risks of oestradiol treatment immediately after childbirth. 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Sex Differences Precipitating Anorexia Nervosa in Females: The Estrogen Paradox and a Novel Framework for Targeting Sex-Specific Neurocircuits and Behavior Charlotte Keating Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 1.1 Stress Induces Reward, and Both Are Linked to the Development of Anorexia Nervosa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 1.2 In the Disorder Maintenance Phase, a Neurocircuit for Reward Contamination May Play a Significant Role in Persistent Poor Decision Making . . . . . . . . . . . . . . . . . . 192 2 Sex-Specific Psychobiological and Pharmacological Explanation for the Disproportionate Development of Anorexia Nervosa in Females: Stress and Reward Sensitivity Triggered by Estrogen at Puberty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 2.1 Evolutionary Conservation: Females Are More Sensitive to Stress and Reward than Males . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 2.2 Estrogen Mediates Increased Sensitivity to Reward in Females . . . . . . . . . . . . . . . . . . . . 196 2.3 Females Are More Vulnerable to Anorexia Nervosa Due to Estrogen-Mediated Stress and Reward Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

3 Neuropsychopharmacology of Treatment Response in Anorexia Nervosa . . . . . . . . . . . . . . . 199 3.1 The Estrogen Paradox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 3.2 A Rationale for the Lack of Efficacy of Serotonin Modulators in Anorexia Nervosa: An Overlooked Mediator of Estrogen in Treatment Response . . . . . . . . . . . . 201 3.3 A Rationale for the Greater Clinical Response to Antipsychotics Versus SSRIs in Anorexia Nervosa? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 4 Conclusions and Future Directions: Estrogen Augmentation of SSRIs or Antipsychotics to Induce/Facilitate Response to Treatment via Normalizing Stress Hyperactivity and the Experience of Reward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Abstract In anorexia nervosa (AN), reward contamination likely plays a signifi- cant role in maintenance of the illness. Reward contamination is a context in which patients’ behaviors of self-starvation and excessive exercise, while initially C. Keating Monash Alfred Psychiatry Research Centre (MAPrc), The Alfred Hospital, 1st floor, Old Baker Building, Commercial Road, Prahran, VIC 3181, Australia e-mail: charlottekeating1@gmail.com J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 189 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010_99, # Springer‐Verlag Berlin Heidelberg 2010, published online 18 November 2010 190 C. Keating rewarding, become aversive, even punishing; but patients may not recognize the punishing and conflicted/contaminated behaviors. An emerging neurocircuit encompassing the anterior cingulate cortex (ACC) has been functionally linked to symptoms including reward contamination and body dysmorphic processing. Owing to the significantly greater prevalence of AN in females, evidence from clinical literature and preclinical models is spearheaded to provide a novel rationale for estrogen triggering sensitivity to the experience of stress and reward, precipitat- ing AN disproportionately in females at the time of puberty. Paradoxically, how- ever, estrogen may facilitate response to pharmacological interventions and (desensitization of the identified neurocircuits) via its contribution to serotonin modulation, hypothalamo-pituitary adrenal (HPA)-axis attenuation, and effects on dopamine. Keywords ACC
Antipsychotics
DLPFC
Dopamine
DRN
Estrogen
HPA- axis
Neurocircuits
OFC
Reward contamination
Sensitivity
Serotonin
SSRI 1 Introduction Anorexia nervosa (AN) is a relatively uncommon illness (affecting up to 4.3% of women across their lifetime, Wade, et al. 2001) but it is predominantly diagnosed in adolescent females, in up to 95% of cases, (DSM-IV-TR 2000) with a prevalence of 0.3–1.3% (Hoek and van Hoeken 2003; Bulik et al. 2006; van Kuyck et al. 2009). Several rationales for the sex-specific predominance of females diagnosed with AN have been proposed; however, this chapter will focus on a novel role for estrogen contributing to the disproportionate precipitation of the illness. Self-starvation and excessive exercise are core illness features (Davis 1997) which have been linked to anhedonia [the reduced capacity to experience reward (Keating 2009)], which is consistent with reports that more excessive exercisers tend to be more anhedonic (Davis andWoodside 2002). The diagnostic relevance of reward to AN remains to be established, albeit the contribution of sensitivity or capacity for reward among patients has been considered an important factor influencing the clinical expression of AN (Davis and Woodside 2002; Keating 2009) and its development (Keating 2009) including the contribution to reward contamination, which likely plays a significant role in the disorders’ maintenance (Keating 2009). Reward contamination is a context in which patients’ behaviors of self-starvation and excessive exercise, while initially rewarding, become aversive or punishing, but patients may not recognize the punishing (and contaminated) features of their behaviors. Contaminated reward processing has been proposed to be mediated by abnormalities in the anterior cingulate cortex (ACC) among a broader network (Keating 2009). Diagnostic criteria for AN does not encompass reward abnormalities, but includes weight relative to height (A), intense fear of gaining weight or becoming Sex Differences Precipitating Anorexia Nervosa in Females 191 fat (B), body weight and shape distortions (C), and amenorrhea in postmenarcheal females (D) (DSM-IV-TR 2000), the latter demonstrating physiological dysfunc- tion. With regard to amenorrhea, there are few differences in demographics, eating behaviors, body image perceptions, illness history, and psychiatric comorbidity distinguishing menstruating and nonmenstruating patients (Garfinkel et al. 1996; Abraham et al. 2005) with many questioning the relevance of this criterion to the illness (e.g., Roberto et al. 2008; Attia and Roberto 2009). Physiologically, elevated stress, hypothalamo-pituitary adrenal (HPA) axis activity is reported in the majority of patients with AN linked to their behaviors (Bergh and Sodersten 1996) and is logically consistent with hypothalamo-pituitary gonadal (HPG)-axis-suppression- induced amenorrhea. This chapter will focus on a novel explanation for a role for estrogen (around puberty) facilitating illness onset disproportionately in females, via enhancing sensitivity to stress and reward associated with AN behaviors. In addition, a paradoxical role for estrogen in the neuropsychopharmacology of response to treatment in AN (Keating et al. 2010) will be developed, the latter owing to estrogen’s relationship to serotonin modulation, HPA-axis modulation, and indirect evidence for an association with reward (dopamine) normalization, of which these systems have been putatively linked to AN. 1.1 Stress Induces Reward, and Both Are Linked to the Development of Anorexia Nervosa Consistent with reports that AN behaviors are linked to anhedonia, the illness has been suggested to develop because it is initially rewarding to eat less food and AN behavior is maintained through conditioning to the situations that provide reward (Bergh and Sodersten 1996; Sodersten et al. 2006, 2008). At a pathophysiological level, the majority of patients present with HPA-axis hyperactivity (Bergh and Sodersten 1996; Keating et al. 2010; Licinio et al. 1996, among others), whereby elevated corticotropin-releasing hormone (CRH) levels, up to 170% of normal, have been linked to self-starvation (Bergh and Sodersten 1996). The physiological sequalae of CRH release is the stimulation and secretion of cortisol from the adrenal glands. Adrenocortical hormones are rewarding because their secretion stimulates the release of dopamine (DA) from the ventral srtiatal terminals of the mesolimbic neurons in the brain via both adrenocortical hormone feedback on these terminals and activation of DA cell bodies in the ventral tegmentum of the mesencephalon (at least in an animal model of the illness, Bergh and Sodersten 1996). Importantly, adrenocortical secretions enhance the reward value of AN-linked behaviors by increasing the release of DA in the terminals of these neurons (Bergh and Sodersten 1996; Piazza et al. 1993), presenting a potently physiologically reinforcing mecha- nism for AN behaviors. 192 C. Keating This explanation encompasses why patients experience their behaviors (exces- sive exercise and food restriction) rewarding in the first instance (Keating 2009) and has been extended psychologically and physiologically, to rationalize why patients continue engaging in these behaviors despite the fact that they are aversive, even punishing (Keating 2009). 1.2 In the Disorder Maintenance Phase, a Neurocircuit for Reward Contamination May Play a Significant Role in Persistent Poor Decision Making There are several neurobiological explanations for development of AN; however, few consider the distinction between factors influencing onset relative to mainte- nance of the illness. This chapter will focus on stress-induced reward linked to the onset of AN, as well as the ultimate contamination of reward and punishment (Keating 2009). While behaviors linked to AN are initially rewarding and asso- ciated with illness onset, reward contamination likely plays a significant role in illness maintenance, due to the fact that patients may ultimately fail to recognize the punishing (or contaminated) features of their behaviors. Reward contamination has been proposed to be physiologically mediated by overlapping neural circuits responsible for processing both reward and punishment (Keating 2009) that become contaminated and reinforced, as a result of pathological and unrelenting engage- ment in disordered-linked behaviors. A body of literature implicates dysfunction in reward processing in AN (reviewed in Keating 2009); however, no studies have systematically investigated reward contamination, that is, patients’ perceptions of punishment associated with challenges where the hedonistic (reward) rating of tasks is assessed (i.e., testing whether a reward-based task is considered punishing, and vice versa, whether a punishing task is considered rewarding, Keating 2009). Recently, however, an investigation in individuals recovered from the illness may indirectly shed clinical light on reward contamination linked to AN. During functional magnetic resonance imaging (fMRI), participants recovered from AN (and healthy controls) were required to process reward and punishing stimuli (e.g., wins and losses on a gambling task) with results demonstrating in recovered individuals that, neurally, the ventral striatum failed to distinguish reward from punishment, whereas healthy controls distinguished these stimuli in the same region (Wagner et al. 2007). While this study did not intend to investigate reward contamination per se, a failure to distinguish between rewarding and punish- ing stimuli in ventral striatum (the region of interest, ROI, in this study, Wagner et al. 2007) in recovered individuals supports the contention of reward contamina- tion, given healthy controls were able to distinguish between these experiences in the same region. Sex Differences Precipitating Anorexia Nervosa in Females 193 Extrapolated to the reward contamination theory (Keating 2009), these results (from Wagner et al. 2007) support the ventral striatum as a reward-contaminated locus in recovered individuals. Moreover, the persistence of neural contamination within this region, following recovery from the illness, suggests that reward con- tamination in the ventral striatum (at least) reflects a vulnerability marker for the illness (Keating 2009), which is furthermore supported by data from an investiga- tion in ill patients, similarly demonstrating dysfunction in this region, again linked to reward contamination, albeit not intending to test this. For example, Fladung et al. (2010) investigated in ill AN patients, activity in the ventral striatum in relation to self-referent processing of pictures of women at different weights, including underweight and normal weight. Although Fladung et al. (2010) were interested in demonstrating reward-linked starvation dependence associated with the ventral striatum (Fladung et al. 2010; Keating 2010), their results may also infer important information regarding body dysmorphic self- perceptions and reward contamination linked to this region in AN (Keating 2010). An argument for interpreting the results by (Fladung et al. 2010) as an illustration of reward contamination is based on the fact that when processing pictures of women at different weights in a self-referent manner; patients demon- strated more positive appraisals correlated with activity in the ventral striatum to underweight relative to normal-weight pictures, reflecting an indirect illustration of reward-conflict given that it would otherwise be expected that an underweight picture may induce feelings of aversion, which is consistent with and supported by the fact that healthy control participants demonstrated the opposite association; e.g., more positive ratings of normal weight compared with underweight women also linked to activity in this region (Fladung et al. 2010). The extent to which reward contamination may reflects a marker for AN in recovered individuals (e.g., interpretations based on data presented in Wagner et al. 2007) as well as symptoms of AN beyond body dysmorphic perceptions (Keating 2010) and neuroanatomically, whether the substrate for these psychological pro- cesses are diffuse within other brain regions, or the likelihood of a neurocircuit, remains to

be directly tested. 1.2.1 An Emerging Neurocircuit for Anorexia Nervosa Neuroanatomy Regarding other regions involved in reward contamination, the ACC has been proposed as a key locus and nexus in reward contamination contributing to disorder maintenance in AN (Keating 2009). This rationale is consistent with both preclini- cal and clinical literature demonstrating its heterogeneous functions in reward (Petrovic et al. 2008; Kennerley et al. 2006) punishment (Wrase et al. 2007) and conflict (Pochon et al. 2008) processing (reviewed in detail in Keating 2009), as well as reward-punishment contamination demonstrated in another psychiatric illness, major depression (Knutson et al. 2008). Abnormalities in structure and 194 C. Keating function of the ACC region are some of the most frequently cited in AN literature (reviewed in Keating 2009); however, there remains to be a consensus on a disorder-specific explanation for a role of the ACC in AN. Empirical evidence for the functional contribution of the ACC to AN, linked to reward, punishment, and the contamination of these experiences has been provided by an analyses of data (Kaye et al. 2009) from recovered individuals (Wagner et al. 2007). Kaye et al. (2009) revealed data that enables an interpretation to support the assertion that recovered individuals fail to neurally distinguish reward and loss (punishment) extending from the ACC (hypoactivated in recovered individuals) through to the ventral striatum, providing further support for a neurocircuit (at least the ACC and ventral striatum) involved in reward contamination. Although a region of interest analysis was not extended to the OFC and dorso- lateral prefrontal cortex (DLPFC) among other executive regions, it is proposed too, these areas, owing to their links to decision making based on reward (and reward history) (e.g., Kerns et al. 2004; Kennerley et al. 2006) as well as abnorm- alities in set-shifting in AN (Zastrow et al. 2009) may also contribute to or enable, reinforcement of disorder linked poor (or contaminated) decision making and action (behavior) selection, for which these regions are putatively involved (e.g., Kerns et al. 2004; Kennerley et al. 2006; Rushworth et al. 2007). Further analysis of more executive regions in recovered individuals (Wagner et al. 2007), but also in ill patients, would reveal the extent to which a neurocircuit may contribute to reward contamination. Furthermore, in the illness state, whether patients “self-referent processing” of pictures of body images (or processing of their own body images) and their experience of reward or punishment (theoretically) linked to these appraisals, extends beyond the ventral striatum, and whether these abnormalities persist in recovered individuals may further reveal the contribution of reward contamination to this pervasive disorder–symptom, as well as presenting another functional biomarker for the illness which may be linked to relapse–risk. Neurochemistry The neurochemistry of AN is complex. Abnormalities present in several systems including the HPA-axis (e.g., Bergh and Sodersten 1996; Licinio et al. 1996), the dopaminergic (e.g., Frank et al. 2005), and the serotonergic systems (which has been extensively reviewed, e.g., Kaye 2008), with persistent abnormalities demon- strated in the latter two systems (e.g., Bosanac et al. 2005) following weight gain. Dysfunction in the DA system is commonly reported, including greater D2 and D3 receptor binding in the ventral striatum during positron emission tomography (PET) (at baseline) in patients recovered from the illness (Frank et al. 2005) as well as abnormalities (overactivity) of the DA system in patients (e.g., Barbato et al. 2006). Functionally, DA has also been linked to processing both reward and punishment (Matsumoto and Hikosaka 2009) (in an animal model). Taken together with the fact that AN is linked to abnormalities in the DA system in the ventral striatum (Frank et al. 2005), and functionally, reward contamination overlaps the same region Sex Differences Precipitating Anorexia Nervosa in Females 195 (based on data in Wagner et al. 2007) and DA has been linked to processing reward and punishment (e.g., Matsumoto and Hikosaka 2009), these findings converge to support the plausible role of DA linked to reward contamination in AN (Keating 2009). Moreover, in the context that upregulated HPA-axis activity leads to stimu- lation and secretion of DA, it is likely that reward contamination (linked to DA) is stimulated and reinforced, and therefore maintained by upregulated HPA-axis activity in the illness. Although estrogen has been largely dismissed as a diagnostic or clinical indica- tor for AN (e.g., Roberto et al. 2008), at puberty estrogen is proposed to contribute to sensitivity to stress-linked reward at the onset of AN. Paradoxically, however, evidence supports the hypothesis that estrogen also contributes to treatment response (Keating et al. 2010) consistent with its interactions with serotonin, the HPA-axis, and DA, postulated to facilitate response to medication that down- regulates the HPA-axis. 2 Sex-Specific Psychobiological and Pharmacological Explanation for the Disproportionate Development of Anorexia Nervosa in Females: Stress and Reward Sensitivity Triggered by Estrogen at Puberty 2.1 Evolutionary Conservation: Females Are More Sensitive to Stress and Reward than Males A complex interaction of factors likely contributes to a biological rationale for the diagnostic predominance of AN (up to 95% of cases, DSM-IV-TR 2000) among females. The disproportionate precipitation of the illness is postulated to reflect distinct evolutionarily conserved differences in females relative to males in sensi- tivity to stress and reward psychobiology, given stress is involved in the onset and maintenance of AN (e.g., Lo Sauro et al. 2008) and the majority of patients with AN demonstrate HPA-axis hyperactivity (Bergh and Sodersten 1996; Keating 2009; Licinio et al. 1996, among others) linked to illness behaviors (Bergh and Sodersten 1996; Keating 2009). Physiologically, stress-induced upregulation of the HPA-axis produces elevated cortisol (reviewed in Tilbrook and Clarke 2006), the consequences of which include increased synthesis and secretion of reward-linked DA in AN (e.g., Bergh and Sodersten 1996). Females in general (clinically and preclinically) respond with greater perturbations of the HPA-axis than males in the context of psychosocial stressors (for review, see Tilbrook and Clarke 2006) and show greater sensitivity to reward than do males (e.g., Kamarajan et al. 2008) of which the sensitivity to the experience of reward is likely to be physiologically mediated via estrogen (e.g., Zakharova et al. 2009). 196 C. Keating Although AN behaviors have been linked to stress-induced reward (e.g., Bergh and Sodersten 1996), the disproportionate diagnosis of AN in females linked to stress, reward and estrogen has until now not been formally hypothesized (neither in other stress-linked illnesses favoring females, e.g., major depression). Indirect support for the relationship between these physiological variables validates the potential for a relationship between these factors contributing to AN (Monteleone et al. 2001). For example, increased cortisol concentrations, but reduced concentra- tions of estrogens (i.e., 17b-estradiol) (among other hormones measured including dehydroepiandrosterone, DHEA), have been reported in AN patients (Monteleone et al. 2001), which is logically consistent with the impact of hyperactive HPA-axis- induced suppression of the HPG-axis. Regarding the molecular dissemination of sex differences in stress and reward potentially contributing to AN, data from at least one psychobiological study can be extrapolated to address this relationship. Recently, differences in the stress, CRH system response to psychosocial stressor challenge were investigated between male and female sheep (Rivalland et al. 2007), and serendipitously for the purposes of the current contention, the positive control was enkephalin-staining, a reward-linked opioid. Following psychosocial isolation restraint stress, among results, female sheep demonstrated a greater proportion of enkephalin (reward-linked) cells stain- ing for Fos than males in both control and stressed animals, suggesting (of particu- lar relevance) a greater volume of reward-linked cells in females, which was present before the stress-induced challenge (i.e., independent of the effects of stressor). Extrapolated to the clinical condition, females may present with a greater proportion of reward-linked neural substrates opposed to the stress system (includ- ing those diagnosed with AN) predisposing females to the disproportionate expres- sion of reward and stress-linked physiology and pathophysiology. Data from Rivalland et al. (2007) may also infer (although speculative) that females (relative to males) may experience dose-dependent greater reward from stress, on the basis of greater enkephalin Fos staining in females. Owing to the greater volume of reward-linked cells found in females in this study, it is plausible (at least indirectly) that estrogen may be putatively involved in mediating the difference in reward between males and females. 2.2 Estrogen Mediates Increased Sensitivity to Reward in Females Evidence suggests that the mechanism mediating greater sensitivity in reward and stress systems in females is estrogen. Evidence from preclinical and clinical research (yet to be tested in patients with AN) suggests a strong rationale for endogenous estrogen concentrations contributing to the sex difference in the expe- rience of reward favoring females (Zakharova et al. 2009; Fattore et al. 2007). In a recent study, younger female mice demonstrated greater behavioral sensitivity to rewarding stimuli (cocaine induced place preference) than older females or male littermates of any age (Zakharova et al. 2009), and consistent with estrogen’s role in Sex Differences Precipitating Anorexia Nervosa in Females 197 mediating sensitivity to reward favoring females, when animals were ovariecto- mized, the sex difference in reward sensitivity was lost. Further support for estrogen involvement in reward sensitivity can be illustrated by a study demonstrating that certain female rat strains (both Long–Evans and Lister Hooded, but not Sprague– Dawley strains) experience greater reward than males, evidenced via greater self- administration of the cannabinoid (CB1 receptor) agonist (WIN 55, 212–2), in addition to which ovary-intact females experienced greater reward than estrogen- treated ovariectomized females (Fattore et al. 2007). These preclinical findings are consistent with clinical research, demonstrating (though less directly) reward sensitivity favoring females. For example, in response to wins and losses on a gambling task, healthy females showed greater sensitivity to reward and loss (wins and losses, or punishment) than males (Kamarajan et al. 2008) in addition to which males were equally sensitive to both wins and losses. The neural correlates of these experiences were determined via brain oscillation, revealing that for females, greater reward sensitivity was linked to greater theta power and posterior maxima in the posterior region of the brain and activity in the anterior region when compared to loss conditions, linked to anterior involvement only. Males, however, demonstrated posterior maxima to both stimuli linked to activation in the frontal midline (Kamarajan et al. 2008). These results support an indirect role for estrogen in reward sensitivity, given females relative to males were more sensitive on relevant conditions of the gambling task. Future studies involving fMRI and PET imaging during ligand-specific binding (e.g., targeting DA) would resolve more specifically brain regions and circuits involved in the sex-specific experience of reward and punishment (or wins and losses), providing relevant insight regarding mechanisms that may lead to reward dysfunction (e.g., contami- nation) and neural substrates driving and maintaining behaviors linked to AN. Although the impact of increasing levels of estrogen, characteristic of changes at puberty on the reward system, have yet to be investigated in AN, evidence for a modulatory impact of estrogen on reward systems can be extrapolated from a study disseminating the impact of concentrations of estrogens (e.g., estradiol) across the menstrual cycle in primates on the expression of the DA (reward-linked) system (Czoty et al. 2009). Specifically, during the luteal phase (high estradiol and proges- terone concentrations) there was greater availability of D2 binding sites (via [18] FCP binding) in the caudate and putamen (e.g., striatum), suggesting greater unoccupied receptors in primates during physiological periods of higher estradiol (and progesterone) (Czoty et al. 2009) which has been suggested to reflect reduced DA release during the high estradiol phase (Young and Becker 2009). Extrapolated to AN, it would be logically consistent that when estrogen levels are chronically low, DA levels are likely high. This can be illustrated by evidence that DA levels in the illness are elevated, as assessed via eye-blink rate (e.g., Barbato et al. 2006), a peripheral marker of central DA activity in patients relative to healthy controls. Furthermore, empirically, in weight-restored patients relative to healthy controls, D2 and D3 receptor binding has been shown to be increased (via [11C] raclopride binding) in the anteroventral striatum (Frank et al. 2005). Although menstrual cycling was not controlled for, it might be that increased D2 198 C. Keating and D3 receptor binding reflects at least in part an impact of estrogen normalization on D2 binding [given three normal cycles were required for inclusion in the study by Frank et al. (2005) (estrogen

normalization and treatment response discussed in Keating, et al. 2010)]. These interpretations are logically consistent with the physiological reports from Czoty et al. (2009) demonstrating that higher levels of estrogen are associated with lower concentrations of DA (Young and Becker 2009) and greater D2 and D3 receptor availability (Czoty et al. 2009). 2.3 Females Are More Vulnerable to Anorexia Nervosa Due to Estrogen-Mediated Stress and Reward Sensitivity Support for sex differences in susceptibility to development of AN behaviors favor- ing females (Hancock and Grant 2009) linked to stress and reward (e.g., Bergh and Sodersten 1996) has been demonstrated in an activity-based rodent model of anorexia nervosa (ABA). Specifically, females were significantly more susceptible to restricted feeding and excessive wheel running, as demonstrated by more rapid and pronounced reductions in body weight and lower levels of food intake, when compared to males (Hancock and Grant 2009). Although endocrine and neurochem- ical measures were not taken, sex differences in the effects of food restriction and wheel running in ABA likely reflect differences in stress (among other endocrino- logical) factors, consistent with findings that HPA-axis reactivity, i.e., levels of adrenocorticotropin hormone (ACTH)/corticosterone (the rat homologue of corti- sol) are greater in females relative to males, at rest and following exposure to a range of stressors, including forced swim (Panagiotaropoulos et al. 2004; Wigger and Neumann 1999), motorized wheel running, immobilization, footshock (Kant et al. 1983), and the chronic mild stress paradigm (Dalla et al. 2005, see chapter x). Taken together, these outcomes (e.g., Hancock and Grant 2009; Panagiotaropoulos et al. 2004;Wigger and Neumann 1999) are consistent with the majority of literature concerning greater responsiveness of the HPA-axis in females than males (Tilbrook and Clarke 2006), and heightened HPA-axis reactivity may provide a risk factor for greater impact of the stress (Hancock and Grant 2009) of a wheel-running stressor (or clinically relevant excessive exercising), and its reward- (DA) linked reinforcement. To test whether estrogen is crucial in mediating the greater vulnerability of females to the development of AN, and the contribution of greater sensitivity to stress and reward-linked systems in this context, a similar paradigm presented in Hancock and Grant (2009) may be tested. In addition to the utilization of continually assessed HPA-axis and DA levels in males and females compared on vulnerability to the ABA model, a study could involve females that are ovary intact, or ovariectomized or ovariectomized with estrogen replacement, at puberty, to determine the contribution of estrogen to the greater vulnerability of ABA in females. Sex Differences Precipitating Anorexia Nervosa in Females 199 Estrogen SSRIs Antipsychotics HPA-axis Overactivity Reduced serotonin Dopamine neurotransmission overstimulation HPG-suppression Treatments Anorexia nervosa treatment targets Fig. 1 A model for treatment targets in anorexia nervosa 2.3.1 Summary In summary, in a model of ABA, females demonstrated greater sensitivity or vulnerability to the development of behaviors mimicking the AN clinical condition (excessive exercise and food restriction) that have been linked to elevated activity of the HPA-axis in clinical participants (e.g., Bergh and Sodersten 1996) and reflect elevated DA secondary to elevated HPA-axis activity in an animal model (Bergh and Sodersten 1996). These assertions are furthermore consistent with reports for the greater impact of varied stressor tasks on females relative to males described. Evidence supports the hypothesis that estrogen mechanistically contributes to the greater sensitivity to reward seen in females relative to males (e.g., Fattore et al. 2007; Zakharova et al. 2009), which may contribute to greater sensitivity around the time of puberty, in the development of stress-induced reward linked to behaviors, disproportionately precipitating AN in females. 3 Neuropsychopharmacology of Treatment Response in Anorexia Nervosa 3.1 The Estrogen Paradox While estrogen has been linked to greater reward sensitivity in females relative to males, empirically rationalized to contribute to the disproportionate diagnosis of 200 C. Keating AN in women, paradoxically, estrogen may facilitate response to pharmacological interventions including selective serotonin reuptake inhibitors (SSRIs) as well as antipsychotics via estrogen’s contribution to HPA-axis attenuation, indirect influ- ence on DA and contribution to serotonin modulation. The importance of estrogen in a clinical response to pharmacotherapy has been previously discussed (Keating et al. 2010). A schematic depicting neurobiological treatment targets for AN based on illness linked suppression of the HPG-axis (e.g., reduced estrogen levels), hyperactivity of the HPA-axis, elevated DA levels, and reduced serotonin levels is presented in Fig. 1. Central to illness maintenance is HPA-axis overactivity. HPA-axis overactivity stimulates DA secretion, reinforcing (contaminated) reward-linked behaviors in AN. HPA-axis overactivity leads to a reduction in serotonin, the consequences of which facilitate HPA-axis overactivity. HPA-axis overactivity ultimately sup- presses the HPG-axis, leading to amenorrhea. Normalizing this context, estrogen treatment can inhibit the HPA-axis (Young et al. 2001) estrogen is involved in the regulation of serotonin (Gundlah et al. 2005) and may facilitate the therapeutic effects of serotonin modulators (e.g., SSRIs) (Keating et al. 2010), ultimately facilitating attenuation of the HPA-axis, the consequence of which may normalize reward via reduced DA stimulation. Estrogen may also facilitate the actions of antipsychotics (e.g., antagonizing DA), reducing (contaminated) reward-linked reinforcement of disorder behaviors. According to this model, treatment approaches involving estrogen and SSRIs or estrogen and antipsychotics may reduce HPA-axis hyperactivity-induced reward linked to the reinforcement of AN behaviors. 3.1.1 Treatments in Anorexia Nervosa The first line pharmacological approach to treating AN has involved the use of SSRIs which act to increase synaptic concentrations of 5-hydroxytryptamine (5-HT, serotonin). Albeit several small trials involving testing a large proportion of antidepressant treatments (75%) in patients with AN have demonstrated some improvement on measures including eating behavior and associated weight gain (and reduction in obsessive symptoms) (e.g., Rossi et al. 2007), there is an extensive body of literature demonstrating a lack of efficacy of antidepressant approaches in positively impacting desire for thinness or weight gain across a range of anti- depressants including tricyclics, SSRIs, and mood stablizers (e.g., Attia et al. 1998; Biederman et al. 1985; Gross et al. 1981; Halmi et al. 1986; Kaye et al. 1998; Walsh et al. 2006). There are several explanations for their lack of efficacy, including the notion that abnormalities in the 5-HT system are not putatively linked to AN (e.g., Sodersten et al. 2008), and that (despite a lack of empirical support) enhancing 5-HT may lead to a dysphoric mood state (e.g., Kaye et al. 2009). Consistent with estrogen’s regulation of 5-HT (e.g., Gundlah et al. 2005), a lack of estrogen in the illness state is proposed to mediate nonresponse to SSRIs (Keating et al. 2010). Sex Differences Precipitating Anorexia Nervosa in Females 201 3.2 A Rationale for the Lack of Efficacy of Serotonin Modulators in Anorexia Nervosa: An Overlooked Mediator of Estrogen in Treatment Response The use of serotonergic modulators in AN is consistent with abnormalities in this system in patients, and dysfunction in this system has been extensively reviewed elsewhere (Barbarich-Marsteller 2007; Kaye et al. 2009; and others). For example, in recovered individuals with AN (restricting subtype), 5-HT transporter binding in the dorsoraphe nucleus (DRN) and anteroventral striatum is elevated (e.g., signifi- cantly increased [11C] McN562 binding potential assed via PET) relative to AN patients with bulimic characteristics (Bailer et al. unpublished, cited in Barbarich- Marsteller 2007). Reduced illness linked 5-hydroxyindolascetic acid (5-HTIAA) levels and elevated recovered state levels (reviewed in Barbarich-Marsteller 2007, logically consistent with elevated transporter binding in the illness state) would infer an association between recovery and augmentation of 5-HT levels; however, empirically medication enhancing 5-HT (e.g., SSRIs) show little benefit (Sodersten et al. 2008; Bergh et al. 1996; Adokat and Kutlesic 1995; Barbarich-Marsteller 2007) beyond facilitating relapse-prevention (e.g., Kaye et al. 2009). The neuro- biological differences in recovered individuals relative to ill individuals, permitting some treatment efficacy of antidepressant medication, is likely linked to estrogen concentrations, but this has yet to be hypothesized or experimentally addressed. The recovered state is a physiological status reflecting re-established estrogen concentrations, as opposed to the ammenorheic illness state. A difference in estro- gen concentrations between these phases may explain the lack of efficacy of 5-HT modulators during the illness as opposed to recovery phase. Support for this contention can be derived from two lines of evidence: that 5-HT is regulated by estrogen (e.g., Gundlah et al. 2005) and that a therapeutic response to SSRIs demonstrated in other related illnesses suggests that treatment efficacy is linked to greater endogenous estrogen concentrations in females (e.g., Pae et al. 2009). For example, where amenorrhea is unlikely to be diagnosed (e.g., in depressed patients that are not severely underweight), females respond more favorably to SSRIs than males (Morishita and Kinoshita 2008), and in women taking hormone replacement therapy (HRT) during menopause, response to SSRIs is greater than in women not taking HRT (e.g., Zanardi et al. 2007). These converging lines of evidence suggest that a lack of efficacy of SSRIs in AN is likely due to severely reduced estrogen in the illness state (Keating et al. 2010), which is consistent with and supported by the fact that in the recovered state, SSRIs are more effective in preventing relapse (e.g., Kaye et al. 2009) when menstrual function is restored. In addition to the observation that 5-HT is regulated by estrogen (Gundlah et al. 2005), antidepressants have been shown to attenuate activity of the HPA-axis (Schule 2006); hence, estrogen may also facilitate recov- ery in AN via its proposed effects in downregulating the glucocorticoid stress response (Solomon and Herman 2009), the consequence of which, in the context of AN, leads to reduced stimulation of DA. 202 C. Keating 3.2.1 Estrogen Reduces Activity of the HPA-Axis Key to addressing the pathophysiology of AN is reducing or hypoactivating over- activity of the HPA-axis, the consequences of which may reduce DA synthesis and secretion, ultimately reducing reinforcement in AN (Keating 2010). Recent evidence from a study involving stress-responsivity in female rats sug- gests definitively that estrogen (but not progesterone) is an important inhibitor of the HPA-axis (Young et al. 2001). Consistent with HPA-axis inhibiting effects of estrogen (Young et al. 2001) and the corollary of reduced estrogen activating the HPA-axis, evidence shows that in females undergoing restraint stress, estrogen antagonists (tamoxifen and C1628) increase responsivity of the HPA-axis; that is, C1628 increased both ACTH and corticosterone, and tamoxifen increased ACTH. Conversely, in ovariectomized female rats, low dose estradiol (over 7 days) decreased HPA-axis responsiveness (e.g., reduced ACTH) to psychosocial restraint stress, whereas progesterone had no effect (Young et al. 2001) (discussed elsewhere, Keating et al. 2010), which is consistent with the fact that both estradiol and progesterone reduced ACTH but that this magnitude did not differ when estradiol treatment was given alone (Young et al. 2001). These findings provide strong evidence for a modulatory impact of estrogen on stress-attenuation and warrant follow-up in AN. 3.2.2 Estrogen Regulates Serotonin and Facilitates Therapeutic Response to Serotonin Modulators Females respond more favorably than males to SSRIs (Morishita and Kinoshita 2008), an effect likely mediated by estrogen. Data from primate and rodent inves- tigations provide evidence that estrogen regulates 5-HT (e.g., Gundlah et al. 2005). For example, in females, 17b-estradiol (E2) likely induces tryptophan hydroxylase (TPH) (5-HT-precursor) expression in the DRN (the largest 5-HT containing nucleus in the brain) of guinea pigs and macaques (e.g., Bethea et al. 2000; Lu et al. 1999) and in murine DRN (Gundlah et al. 2005). In addition, estrogen regulation of TPH (subtype 1) may be specific to the estrogen receptor (ER) b-subtype, on the basis that estrogen increases TPH (subtype 1) expression (selec- tively) in the DRN of wild-type and ER-a knockout mice, where this effect on TPH (subtype 1) is not seen in ER b-knockouts (Gundlah et al. 2005). At least in the context of major depression, which similarly to AN presents with significant abnormalities in 5-HT function and HPA-axis hyperactivity; endoge- nous concentrations of estrogen have been shown to influence response to 5-HT modulators. In a recent study, Zanardi et al. (2007) have demonstrated that meno- pausal women taking HRT (despite complex drug combinations between patients) reported a significant improvement in response to treatment (and reduction in depressive symptoms). These findings are consistent with other reports for greater endogenous concentrations of estrogen favoring response to 5-HT modulators (e.g., Pae et al. 2009; Morishita and Kinoshita 2008), consistent with the finding that Sex Differences Precipitating Anorexia Nervosa in Females 203 females respond to antidepressants more favorably than males (Morishita and Kinoshita 2008 and see chapter

by Sramek and Cutler). Although yet to be experimentally addressed in patients with AN, a lack of empirical support for the efficacy of medication that enhances 5-HT (e.g., SSRIs) (Adokat and Kutlesic 1995; Barbarich-Marsteller 2007; Bergh et al. 1996; Sodersten et al. 2008) beyond facilitating relapse-prevention (e.g., Kaye et al. 2009) in ANmay be due to a lack of estrogen. In sum, estrogen may facilitate SSRI (i.e., 5-HT) induced hypoactivation of the HPA-axis, the consequences of which reduce DA stimulation and reward-linked behavioral reinforcement. 3.3 A Rationale for the Greater Clinical Response to Antipsychotics Versus SSRIs in Anorexia Nervosa? Antipsychotic medication has more recently begun being trialed in patients with AN, and evidence suggests that antipsychotics show promise in the treatment of AN albeit further treatment controlled trials are necessary to conclusively support their widespread clinical use (Court et al. 2008). In the context of the current neurobiological explanation for AN, it is plausible that antipsychotics show enhanced efficacy over SSRIs on the basis that they antagonize DA receptors, which may theoretically reduce the reward-linked reinforcement associated with illness behaviors. DA blocking is a direct target of antipsychotics, whereas it is a downstream consequence of SSRIs, that is, achieved via a consequence of HPA-axis downregulation. Assuming reward- linked reinforcement is key to illness maintenance (via maintaining reward- conflict) in some patients, an approach directly targeting this system may be warranted, whereas in patients with lesser reward sensitivity (e.g., less excessive exercisers) SSRIs and estrogen may be appropriate (Keating et al. 2010). The therapeutic value of antipsychotics in AN may furthermore be augmented by an estrogen adjunctive. This assertion is supported by evidence demonstrating, physiologically, a link between normalization of estrogen levels in recovered AN patients and DA, and is consistent with primate literature demonstrating that greater concentrations of estrogen (according to the luteal phase of the menstrual cycle) in association with greater availability of D2 binding sites (or unoccupied receptors during relatively elevated estradiol) (Czoty et al. 2009) and reduced DA release [consistent with findings from (Czoty et al. 2009) discussed in (Young and Becker 2009)]. So while in healthy primates, higher levels of estrogen are associated with lower concentrations of DA (Young and Becker 2009) based on the findings by Czoty et al. (2009) in AN, the opposite is seen. That is, concentrations of DA are high (Barbato et al. 2006) (e.g., overactivity of reward) and estrogen levels are low (Monteleone et al. 2001) reflecting amenorrhea. It will be important in future to establish the relative efficacy of SSRIs and estrogen versus antipsychotics and estrogen in this patient group. 204 C. Keating 4 Conclusions and Future Directions: Estrogen Augmentation of SSRIs or Antipsychotics to Induce/Facilitate Response to Treatment via Normalizing Stress Hyperactivity and the Experience of Reward Given HPA-axis activity is significantly elevated in AN (e.g., Bergh and Sodersten 1996; Licinio et al. 1996) consistent with elevated DA concentrations (Barbato et al. 2006) and estrogen has been shown to inhibit the HPA-axis during psychoso- cial stress (Young et al. 2001), as well as regulate 5-HT metabolism (Gundlah et al. 2005), it is logically consistent then that an AN-linked deficit in estrogen concen- trations may contribute to elevated activity of the HPA-axis, and furthermore enable hyperactivity due to disadvantaging the capacity of 5-HT to attenuate the HPA-axis. 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Tonge Contents 1 Autism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 1.1 Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 2 Fragile X Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 3 Autism: Prevalence and Gender Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 4 Fragile X Prevalence and Gender Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 5 Autism: Clinical Presentation and Gender Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 6 Fragile X: Clinical Presentation and Gender Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 7 Autism: Cognition and Gender Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 8 Fragile X: Cognition and Gender Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 9 Autism and Fragile X Gender Difference Theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 10 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 Abstract Gender is an important factor to consider in understanding the clinical presentation, management, and developmental trajectory of children with neuro- psychiatric disorders. While much is known about the clinical and neurobeha- vioural profiles of boys with neuropsychiatric disorders, surprisingly little is known about girls. The aim of this chapter was to review our understanding of gender by considering the most prevalent childhood onset neuropsychiatric dis- orders, autism and Fragile X syndrome. This chapter highlights findings which suggest that girls with autism and Fragile X syndrome show some unique differ- ences in cognitive and clinical profiles when compared to boys with these condi- tions; this may indicate the need for innovative assessment and management approaches which take gender into consideration. Our understanding of how differ- ences emerge in boys and girls with neuropsychiatric disorders is unclear, future N.J. Rinehart, K.M. Cornish, and B.J. Tonge (*) Centre for Developmental Psychiatry and Psychology, School of Psychology and Psychology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia e-mail: bruce.tonge@monash.edu J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 209 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010_96, # Springer‐Verlag Berlin Heidelberg 2010, published online 1 October 2010 210 N.J. Rinehart et al. research needs to focus on the role of biological maturation rates, sex hormones, and psychosocial factors in order to progress this field. Keywords Autism
Cognition
Fragile X syndrome (FXS)
Genetic Disorder
Gender
Intellectual Disability
Mental Health
Neurodevelopmental Disorder
Social Functioning Sex differences in the prevalence of psychiatric disorders in children and adoles- cents have consistently been identified in epidemiological studies beginning with the landmark Isle of Wight study (Rutter 1989). Approximately twice as many prepubertal boys have psychopathology compared to girls, but the rates become more equivalent in adolescence. Changes in rates are also influenced by the type of disorder. Males are more vulnerable to suffer from attention-deficit hyperactivity disorder (ADHD) and autism in childhood, but as boys mature ADHD may become less prevalent and conduct disorder and substance abuse more prevalent (Rutter et al. 2003). A meta-analysis of 26 population studies found that the prevalence of depression doubles from childhood to approximately 5.6% in adolescence and is higher in females (5.9%) than in males (4.6%) (Costello et al. 2006). More young girls than boys are likely to suffer from depression, and following puberty this female preponderance for anxiety increases to around twice that for males (Lewinsohn et al. 1998). The causes of these gender differences are unclear, but an interaction between biological, psychological, and social factors are likely (Rutter et al. 2003; Nolen-Hoeksema et al. 1999). Lewinsohn et al. (1998) suggest that the female vulnerability to anxiety is based on genetic factors, but others claim that vulnerability to depression and emotional problems in females is strongly influenced by the effects of socialization, sensitivity to interpersonal relationships, the sense of mastery, self regulation, and response to stress (Nolen-Hoeksema et al. 1999; Kennan and Shaw 1997). Epidemiological studies of populations of twins and more recently the application of molecular genetics in longitudinal studies provide a method to describe gene–environment interactions contributing to psy- chopathology (Foley et al. 2004). A particularly useful way to investigate the “nature versus nurture” effects of gender on psychopathology is through studies of disorders that have a strong genetic component (henceforth referred to as “neurodevelopmental disorders”). Approximately, 3% of children will be born with a neurodevelopmental disorder equating to approximately 650,000 individuals in Australia alone. The impact of “nature” versus “nurture” is infinitely more complex in neurodevelopmental disorders where the interaction between prenatal hormones, specific susceptibility genes, and risk or protective genes on the X chromosome operates (Rutter 2005). The genetic mechanisms that result in a higher prevalence of males with child-onset neurodevelopmental disorders, including those for which genetic etiology, are still not determined, such as autism, as well as those disorders for which the genetic origins are known, such as fragile X syndrome (FXS), allow investigation of gender-related differences in prevalence, clinical manifestation, and cognitive and neuropsychiatric profiles. However, Gender Differences in Neurodevelopmental Disorders 211 across the neurodevelopmental disorder literature, little attention has been paid to the way in which downstream biological maturation rates, sex hormones, and psychosocial environments differentially impact on the developmental trajectory for male and females. The focus of this chapter will be to overview the clinical, cognitive, and neurobio- logical literature on gender differences in the most prevalent childhood onset neu- ropsychiatric disorders, autism and FXS, the latter being the most common cause of hereditary intellectual disability in males, resulting from the silencing of a single gene on the X chromosome. Thompson et al. (2003) have extensively reviewed the literature on gender differences in neurodevelopmental disorders and concluded that gender has yet to matter sufficiently in neurodevelopmental disorder research, and by extension clinical practice. The almost exclusive focus on males with neuro- developmental disorders in the biological and clinical research literature has led to an imbalance in gender-specific information, which can inform the clinical assessment and management of females with neurodevelopmental disorders. In this chapter, we will highlight the important gender differences that necessitate careful investigation of male and female profiles across development to facilitate targeted gender-specific clinical and educational interventions and treatments. 1 Autism 1.1 Diagnosis Autism is a generic term referring to a group of related conditions defined in the DSM-IV-TR (American Psychiatric Association 2000) and the ICD-10 (World Health Organisation 1992) as pervasive developmental disorders (PDD). These disorders have their onset

within the first 3 years of life, but the clinical picture may change with development. In DSM-IV-TR (American Psychiatric Association 2000), the PDDs comprise the categories of autistic disorder, Asperger disorder, Rett’s disorder, childhood disintegrative disorder, and PDD – not otherwise speci- fied (PDD-NOS). Autism was first described by Leo Kanner in 1943 in a group of 11 children who had the distinctive core features of social, language, and commu- nication disturbance, and an obsessive desire for sameness (Kanner 1943). In the following year, Hans Asperger described a group of 16 children and adolescents in Vienna who had deficits in communication and social skills together with obses- sional interest, intolerance of change, and motor clumsiness (Asperger 1944). Unlike the children described by Kanner, these young people were of normal intellectual ability and did not have any delay or abnormality in their language development. This has become the differentiating feature of Asperger disorder from autistic disorder. All children with autism have impaired social interactions, which may change as they develop. Infants with autism do not anticipate social interactions, such as being 212 N.J. Rinehart et al. picked up, or seek physical comfort or parental attention. Preschool children with autism usually avoid eye contact and do not engage in social imitation such as waving goodbye. They are unresponsive to the feelings and emotions of others. They are aloof and unable to engage effectively with other children or understand reciprocal social interactions. As the child grows older, there may be an increased interest in other people, but social skills are often stilted and learned in an inflexible manner, leading the child to appear odd and socially clumsy. Parents usually first seek help because their child has language delay and a lack of nonverbal commu- nication, and easily becomes frustrated. About 50% of children with autism fail to develop functional speech and only learn slowly to compensate with gesture. Language development is often abnormal in the remainder, with echolalia, self- directed jargon, and the repetition of irrelevant phrases, for example from a TV show. The correct use of pronouns and the related development of a sense of self and others are delayed. Poor comprehension, problems expressing needs by words and gesture, and difficulty in social understanding are frequently the causes of frustration and disturbed behavior. Children who do develop functional language usually have difficulty in using language socially and in initiating or sustaining a reciprocal conversation. For example, the child may talk at others in a socially inappropriate manner. In contrast to children with autistic disorder, young people with Asperger disorder have no delay in the development of normal expressive and receptive language, including the use of communicative phrases by the age of three. However, children with Asperger disorder have problems in their social use of language, for example being verbose and preoccupied with a favorite topic. Their speech may appear odd due to the use of an unusual accent, or the presence of abnormalities in pitch and volume, leading, for example, to a flat and monotonous delivery. The play, behavior, and daily life of children with autism are usually rigid and repetitive. Younger children may line up toys or objects, or be preoccupied with special objects such as stones, and become distressed if these activities are interrupted. Their ritualistic play lacks imagination and social imitation. With development, play may become more complex, such as re-enacting scenes from a favorite video story, but is usually still repetitive. The older child may develop preoccupations with themes such as train timetables or dinosaurs, and this will be the focus of their play, drawing, and conversation. They may have a number of rituals associated with daily life, such as a fixed order for bathing and dressing, or an insistence on wearing the same clothes or taking the same route to a familiar place. Change or unexpected events can be distressing: for example, the arrival of a new student in the classroom. There may be a number of perceptual or sensory abnormalities such as hyperacusis or tactile sensitivity, manifesting, for example, as an aversion to having their hair brushed. Some children with autism have a remarkable lack of sensitivity to pain. Children with autism are usually visually attentive: for example, they may study the detail in a picture book or closely observe spinning wheels, the edges of objects, or reflections in water. There are usually some motor mannerisms, such as hand flapping, or tiptoe walking and gait abnormality. Gender Differences in Neurodevelopmental Disorders 213 Approximately 80% of children with autism also have intellectual disability, and a range of other emotional and behavioral disturbances is common. Children with autistic disorder who have intellectual abilities within the normal range are referred to as high functioning. The individual cognitive profiles of children with autism usually show a wide scatter of abilities, with deficits in verbal and social compre- hension tasks, and more ability with visuomotor performance skills. In contrast, children with Asperger disorder have overall normal intellectual abilities, but usually have relative deficits in visuomotor tasks and motor skills compared with their verbal performance. For the sake of brevity, autism and Asperger disorder will henceforth be referred to as “autism.” 2 Fragile X Syndrome FXS was first described in 1943 by Martin and Bell (originally labeled the “Martin- Bell” syndrome) and is the world’s most common hereditary cause of developmen- tal delay in males. The disorder is caused by the silencing of a single gene on the long arm of the X chromosome at q27.3. The gene, named the Fragile X Mental Retardation Gene-1 (FMR1), was identified in 1991 and is “turned off” in affected individuals. When this occurs, there is an expansion of a trinucleotide (CGG) in the repeat region. In individuals unaffected by FXS, there are between 7 and 55 CGG repeats, with 30 repeats the most common number. In clinically affected individuals (known as the full-mutation status), the CGG region expands to over 200 repeats, resulting in silencing of the gene and loss of the fragile mental retardation protein (FMRP). The extent to which these molecular discoveries explain the behavioral phenotypic outcomes in FXS is beginning to be revealed (see also Cornish et al. 2008, for a recent review of the genetic-cognitive/behavioral correlates that com- prise the fragile X continuum). The clinical features that can characterize FXS include an elongated face, large prominent ears, and forehead, and in males, postpubertal macroorchidism (Cornish et al. 2007a; Lachiewicz et al. 2000). More subtle features can include narrow inter- eye distance, a highly arched palate of the mouth, and hyperextensible joints. However, the wide variability in manifestation in both boys and girls makes a diagnosis based on physical features alone almost impossible. It is precisely because of their relatively “normal” appearance that many affected children are not diagnosed with FXS until relatively late in their development. Undoubtedly, the most defining feature, especially in boys with the disorder, is intellectual disability and the resulting cognitive-behavioral phenotype, most notably the attentional control difficulties, language, and spatial impairments that can accompany the syndrome from very early in development (Abbeduto et al. 2007; Cornish and Wilding 2010; Cornish et al. 2007b; Scerif et al. 2004, 2007). Undoubtedly, behavioral problems often link with cognitive impairment, and two disorders in particular that co-exist in many individuals with FXS are autism and ADHD. Due to the pervasiveness of these symptoms, a diagnosis of FXS may 214 N.J. Rinehart et al. occur later in childhood or never at all if clinicians are unable to dissociate the FXS phenotype from a diagnosis of autism or ADHD. To address this concern and provide much needed information to clinicians and educators, the findings from a series of recent studies have begun to elucidate the FXS “signature” associated with both autism and ADHD. Among the most distinctive and pervasive behavioral features of young boys with FXS are attentional and hyperactivity problems (Cornish et al. 2001a; Hatton et al. 2002; Sullivan et al. 2007), the severity of which often leads to a clinical diagnosis of ADHD. At a finer-tuned level, however, the FXS profile appears to be characterized by unexpectedly extreme levels of inattentiveness, restlessness, fidg- etiness, impulsive tendencies, and distractibility even when their level of general development is taken into account. In one of the most comprehensive study’s to date, Turk (1998) compared the ADHD profiles of 49 FXS boys (aged 4 –16 years) to that of 45 boys with Down syndrome (aged 4 –16 years), and 42 boys with mental retardation of an unknown cause (aged 4 –16 years). Although both groups of boys showed similar levels of motor activity, the boys with FXS show signifi- cantly more inattentiveness, restlessness, fidgetiness, distractibility, and impul- sive tendencies suggestive of DSM-IV ADHD predominantly inattentive type. Moreover, there is some evidence that these features do not necessarily improve with age (in contrast to most children with these traits), emphasizing the need for early diagnosis and multidisciplinary intervention. In girls with FXS, the research is not as extensive as that undertaken in affected boys but nonetheless points to a substantive minority of girls presenting with ADHD-inattentive type symptoms (Mazzocco et al. 1998). Together, these findings highlight a distinctive ADHD profile in the FXS full mutation that is not solely the artifact of intellectual disability. One of the most intriguing and complex of relationships in FXS is its association with autism. There are currently very few single-gene disorders for which there is a certainty of the involvement of autism; FXS is one. As a single-gene disorder, FXS offers an interesting genetic model to explore the functions of FMRP regulation and the repercussions of its loss in early brain development. Commonalities across core social and language domains define the link between FXS and autism, and it therefore seems highly plausible that similar neurobiological mechanisms are affected in both disorders. A recent study by Loesch and colleagues found that a common impairment in verbal skills best described the comorbidity of FXS and autism at the cognitive level (Loesch et al. 2007). In an earlier study, Philofsky et al. (2004) reported a similar link in children with FXS between exceptionally low verbal ability, in this case receptive language, and a dual diagnosis of autism, compared to children with FXS alone in which verbal skills appeared to be a relative strength. Overall, children with a dual diagnosis tend to display more impaired cognitive performance than children with either autism alone or FXS alone. However, although commonalities between FXS and autism appear quite striking at one level, subtle differences are notable. For example, in terms of eye gaze, in children with autism atypical eye gaze is most acute in social interactions Gender Differences in Neurodevelopmental Disorders 215 and appears to be motivated both by a lack of understanding of the social situation itself and by the absence of a desire to communicate. In contrast, eye gaze behavior in FXS does not appear to be guided by a lack of social awareness or communica- tion. The majority of individuals with FXS, although tending to avoid social interactions, will offer what is now classically termed the “fragile X handshake,” whereby an initial wish to communicate socially, with a “handshake,” a socially acceptable remark or even brief initial eye contact, is coupled with active and even persistent gaze avoidance. Subsequent interactions with familiar persons may be marked by the same active gaze avoidance despite the growing relationship. The gaze avoidance persists even when attempts are made to extinguish it; it may, in fact, increase in intensity. It has been suggested that FXS is associated with a unique pattern of hyperarousal and social anxiety that can cause them to avert their eyes in a social situation (to avoid the sensory stimulation of eye contact) but may still wish to communicate socially (Cornish et al. 2004a; Wolff et al. 1989). Thus, individuals with FXS are more likely to exhibit autistic-like behaviors such as eye gaze aversion, which are more symptomatic of their hyperarousal and social anxiety rather than from an inherent lack of understanding of the social situation. See Cornish et al. (2007a) for more detailed descriptions of the commonalities and differences between FXS and autism across cognitive domains. The frequency of autism among FXS individuals is still controversial, but approximately 2–6% of children with autism will have the FMR1 mutation (Reddy 2005; Wassink et

al. 2001), and between 33% and 67% of children with FXS will fulfill the diagnostic criteria for autism (Clifford et al. 2007; Rogers et al. 2001) with more males than females reportedly meeting the autism cut-off. 3 Autism: Prevalence and Gender Differences It is well established that there is a greater preponderance of males than females with autism. The magnitude of gender ratio differs with intellectual ability. For children with autism who have associated intellectual disability (referred to in the literature as low-functioning autism, LFA), the gender ratio is approximately 2:1. For children with autism who have above-average intellectual abilities (referred to as high-functioning autism or Asperger disorder), the ratio goes up to 10:1 (Baron- Cohen et al. 2005). There is evidence that the prevalence of autism is increasing. Fombonne, DuMazaubrunc, and Grandjean (Fombonne 2003) reported rates of 10–12 per 10,000 using rigorous diagnostic criteria and standardized diagnostic assessment. Prevalence estimates increase substantially when the broader autism spectrum is included, and a broader range of assessment techniques are used. In Australia, the estimate of around 1 in 160 was given for children between the ages of 6 and 12 years (Australian Advisory Board on Autism Spectrum disorders). Similar figures have been reported by the US Centre for Disease Control (CDC 2007), estimating a prevalence figure of 1 in 150, for 8-year-old children diagnosed with an “autism 216 N.J. Rinehart et al. spectrum disorder.” Liu et al. (2010) recently reported prevalence clusters of children with autism which related to groups of parents who were more informed about the condition through knowing a family or affected child with autism within the community. Liu et al. (2010) noted that these parents were more likely to seek a formal diagnosis, than those parents who had not had community contact with the diagnosis of autism. 4 Fragile X Prevalence and Gender Differences FXS affects approximately 1 in 2,500 males (Hagerman 2008). The focus initially in females with FXS has been on those with significant cognitive deficits. However, the spectrum of involvement includes those with learning difficulties and/or emo- tional problems with an IQ in the broad range of normal. Since most females with the full mutation fall in this category, the prevalence of affected females including this milder involvement will be greater than 1 in 8,000. In the FXS full mutation (>200 repeats), X linkage means that males are especially vulnerable to the full effects of the condition at the brain, behavioral, and cognitive levels. Almost all boys will present with moderate intellectual disability with profiles emerging as young as 3 years of age (Skinner et al. 2005). In females, the phenotypic variation is such that some girls only show subclinical learning disabilities (Bennetto and Pennington 2002), while approximately 25% display more significant cognitive impairment (most with mild ID and rare individuals with moderate ID) similar in profile to boys with FXS. Genetic variation in the form of X-inactivation (when one of the two X chromosomes remains inactive and the other active) is seen as the major contributor to the heterogeneity of intellectual disability and the broad range of cognitive deficits seen in females with FXS. For obvious reasons, this is not an issue of concern in FXS males whose impairment, without the protection of X- inactivation, shows greater severity. In males, FMRP level accounts for about 75% of the variance in IQ, but in females the proportion is much smaller (Lightbody et al. 2006). 5 Autism: Clinical Presentation and Gender Differences There is no evidence that the core symptoms of autism differ for males and females. Volkmar et al. (1993) compared males and females with autism on the Autism Behavior Checklist, age of onset, and ratings of ICD-10 (World Health Organisa- tion 1992) items. They found no consistent gender differences between males and females that were not related to intelligence (IQ). These findings were consistent with those of Pilowsky et al. (1998) who found no gender differences in a matched Gender Differences in Neurodevelopmental Disorders 217 sample of 18 males and 18 females on two commonly used autism assessment tools, the ADI-R (Le Couteur et al. 1989) and the Childhood Autism Rating Scale (Schopler et al. 1988). While the core symptoms of autism are the same in males and females according to DSM-IV-TR criteria, the clinical picture may differ in a way which is con- sistent with gender-related differences in the normal population of male and female children. For example, differences in emotional expression, play interests, language, cognitive profile, and social relationships (Thompson et al. 2003) may give rise to differences in the way males and females with autism present clinically. While boys may have an intense preoccupation with vehicles, such as trains and cars, girls may develop their special interests in areas such as, teddy-bear or doll collections, and spend unusual amounts of time on craft, and art, to the exclusion of other types of play (Gillberg and Coleman 2000). Gender-neutral activities such as “drawing” may form the “special interest” for either males or females with autism. Gillberg and Coleman (2000) reported that females tend to have fewer special interests than males with autism, although this may relate to male interests being more circumscribed (e.g., trains, cars) than female interests (e.g., craft, doll play), and thus more clinically salient. Normally intelligent females with autism may present as more passive, socially competent, and with better communication skills than boys. This may again link to what we know about gender differences in males and females in the typically developing population. For example, Skuse (2009) reported that among children who have higher verbal intellectual abilities in the general population, males are more vulnerable than females to deficits in social-communicative functioning. If we extend these typical gender differences to the autism population, we would expect that females would present more competently than IQ-matched males with autism who may be more obviously socially awkward. The explanation for females with autism presenting as more socially competent may be more simply explained in terms of gender differences in biological maturation rates which affords develop- mental advantages for females, but not males with autism. While the clinical presentation of females with autism may appear superficially different to that of males, females experience the same, if not greater, levels of social isolation and disadvantage as males with autism. Using the Autism Diagnos- tic Interview (ADI) items, McLennan et al. (2005) reported that females were described as having more severe social deficits than males with autism. These social deficits were particularly evident during adolescence in peer relationships with none of the females in the study having any sort of reciprocal friendship after age 10. Holtmann et al. (2007) reported that females have more social, thought, and attentional problems than matched boys with autism as rated by their parents using the Child Behavior Checklist. However, Holtmann et al. (2007) suggest that these parent reports may themselves represent a bias in behavioral expectations for males and females, rather than a “true” gender difference in psycholopathology and behavioral functioning (Rutter 2005). The superficially more competent social functioning of females with autism may result in a late diagnosis or misdiagnosis of the disorder. Gillberg and Coleman 218 N.J. Rinehart et al. (2000) reported that normally intelligent females with autism are referred to clinical services later than males with high-functioning autism. This finding may fit with the common referral pattern to psychiatric/psychological services to preference males who tend to have higher levels of disruptive behavioral disorders which impact more broadly on the family and school setting, than females who tend to have higher levels of internalizing symptoms. Children with autism who present with a passive and often “dreamy” clinical presentation, and also experience learning difficulties at school, may initially be given a diagnosis of attention- deficit disorder (ADD). It may be that this referral pathway is more common for females than males with autism, given the gender-mediated differences in clinical presentation, although there is no data to specifically make this distinction in diagnostic pathway. Other potential misdiagnoses for females with autism include a primary anxiety disorder, selective mutism, and anorexia nervosa (Thompson et al. 2003). Another potential clinical pathway is for females with autism to be initially assessed as having an insecure attachment disorder; this presentation together with the often overprotective parenting response it elicits (Soppitt 2006) may erroneously lead to psychological interventions focused on parenting or family functioning, rather than appropriate autism-focused intervention. The focus on “over” parenting to account for the insecure attachment presentation of girls with autism has many parallels with the “refrigerator,” “under” parenting hypothesis used to account for the aloof and detached presentation of boys with autism in the 1950s. 6 Fragile X: Clinical Presentation and Gender Differences Severity of clinical/behavioral difficulties in FXS males and females will vary across and within gender. For example, hypersensitivity and hyperarousal are recognized as early prominent behavioral features of children with FXS, with and without autism (Belser and Sudhalter 1995; Miller et al. 1999). For example, in girls with FXS, Keysor et al. (2002) demonstrated higher arousal levels at baseline relative to girls with Turner syndrome and typical developing control children, with a small rise on anxiety-provoking cognitive tasks compared to that seen in girls with Turner syndrome, resulting in eventual comparable anxiety in both groups on these tasks. In terms of ADHD symptomology, there is a well-documented profile in males (Asperger 1944), but in contrast in FXS girls, the profile is less well documented with more variability. Unlike affected boys, only about one-third of girls appear to meet the DSM-IV diagnostic criteria for ADHD although many will present with some ADHD symptomology, notably inattentiveness rather than hyperactivity (Mazzocco et al. 1998). For recent reviews, see Cornish et al. (2004b) and Hatton et al. (2009). However, it is also likely that gender differences in clinical presentation will be related to severity of IQ and the presence or absence of comorbid autism. Gender Differences in Neurodevelopmental Disorders 219 7 Autism: Cognition and Gender Differences In addition to environmental (e.g., parental expectation) and biological explana- tions (e.g., biological maturation rates) which may account for gender differences in autism, there may be a neuropsychological explanation for differences in clinical presentation between males and females. Early studies comparing cognitive functioning in males and females with autism reported no noteworthy gender differences other than the level of intelligence (Volkmar et al. 1993; Tsai and Beisler 1983; Pilowsky et al. 1988). In one of the earliest studies of gender differences in autism, Lord et al. (1982) compared male and female children (3–8 years) on a range of nonverbal measures including intelligence, adaptive functioning, receptive vocabulary, perception, and eye– hand integration, as well as on affect, play, and relating human interest. While males were found to exhibit more unusual visual responses and inappropriate stereotypical play than females, the females in the study were found to be more impaired on every measure relating to cognitive functioning than boys including IQ, the Vineland social quotient, receptive vocabulary, eye–hand integration tasks, and perceptual skills. More recent studies focused on normally intelligent children with autism (i.e., high-functioning autism or Asperger disorder) have indicated that gender differ- ences may exist, laying suggestion for a gender-related neuropsychological pheno- type (Kopp and Gillberg 1992). A recent study by Carter et al. (2007) comparing the cognitive profiles of toddlers with autism showed that males displayed stronger verbal and motor skills than girls, whereas girls exhibited better nonverbal problem- solving ability than boys. In the most recent study on gender differences in autism, Koyama et al. (2008) compared the cognitive profiles of children with high- functioning autism using a Japanese version of the Wechsler Intelligence Scale for Children – Third Edition. While no differences were observed in overall IQ scores, gender differences were observed on particular subtests: females outper- formed males on tests of processing speed, coding, and symbol search, whereas boys were significantly better than girls on the block design subtest. Nyden et al. (2000) have shown that females with autism have more impaired executive functioning when compared to males. Lemon et al. (2010) recently showed that females with autism have significantly more impaired executive functioning, in particular, response inhibition, when compared to typically devel- oping females. No differences were found between males with and without autism on this test of executive function. The subtle profile and intellectual differences

between males and females are largely consistent with the only brain imaging study to look at gender differences in autism. Using magnetic resonance imaging, Bloss and Courchesne (2007) found that when males and females are matched on verbal and nonverbal intellectual ability, there was no difference in the pattern of brain abnormalities; however, females were associated with additional abnormalities in cerebral white and grey matter, and temporal grey matter (Bloss and Courchesne 2007). It was suggested 220 N.J. Rinehart et al. that these neurological gender differences may index etiological and downstream biological maturational differences in males and females with autism. Such neuro- biological differences may also account for some of the suggested phenotypical gender-related differences between males and females with autism. More significant white and grey matter abnormalities may account for Gillberg and Steffenberg’s (1987) earlier finding that being female puts an individual with autism at greater risk for behavioral and or cognitive deterioration postpuberty, with 12% of males and 50% of females showing deterioration in one or both domains. Minshew (1991) refers to puberty as marking a “second-wave” of frontal deficits for young people with autism: Future research should focus on different trajectories of fronto-striatal executive impairment for females and males with autism pre- and postpuberty. Put in a clinical context, mapping of executive dysfunction for females across this critical developmental period may provide an important clinical indicator of risk for postpuberty clinical deterioration. This type of research would help clarify whether clinical reports of high levels of frontally mediated psychopathology [e.g., social, thought, and attention problems (Holtmann et al. 2007)] are best accounted for by “nature” (e.g., parental expectations for females) or “nurture” [e.g., increased frontal-susceptibility in females; see Lemon et al. (2010)]. It will also be important for future research to feed-in what we know from the typically developing literature about differences in cognitive processes which characterize males and females. For example, higher levels of psychopathology in females with autism may relate to Canli and Amin’s (2002) finding that females are better than males at remembering emotional issues and events; this possibly gender-mediated cognitive predisposition, accompanied with the obsessional thought patterns which are core to autism, may result in a tendency for females to ruminate more and become increasingly mentally unwell over time. 8 Fragile X: Cognition and Gender Differences At the intellectual level, the majority of FXS males (>95%) will display IQs within the moderate-to-severe range of impairment, with profiles emerging as young as 3 years of age. In females, the phenotypic variation is such that some girls only show subclinical learning disabilities, while approximately 50% display more moderate-to-severe mental retardation similar in profile to boys with FXS. As already noted, the X-inactivation status (ratio of normal alleles on the X chromo- some) in FXS females is seen as the major contributor to the heterogeneity of intellectual disability and cognitive deficits. Surprisingly, however, few studies have addressed the issue of whether degree of intellectual impairment changes with age, albeit progressing at a slower pace compared to typically developing children, or whether intellectual level actually decreases with increasing age, or even remains static across developmental time. Although published studies have consistently observed a decline in cognitive abilities from middle-late childhood onwards (Fisch et al. 1999, 2002), Cornish et al. (2004b) have previously argued Gender Differences in Neurodevelopmental Disorders 221 that this decline might possibly be due to the FXS child’s increasing problems in maintaining and developing successful cognitive strategies that keep pace with their age-normed cohort rather than an actual regression in intellectual level or failure in neural development. However, few, if any, studies have examined intellectual decline and its relation to cognition in females, and fewer still have examined any profile beyond late childhood. At the cognitive level, at least in males by late adulthood, relative strengths in vocabulary (Roberts et al. 2007), long-term memory for meaningful and learned information (Munir et al. 2000), and visual-perceptual skills (Cornish et al. 1999; Kogan et al. 2004) are accompanied by relative weaknesses in the storage and manipulation of complex information in working memory (Munir et al. 2000; Lanfranchi et al. 2008), linguistic processing (Abbeduto et al. 2007; Belser and Sudhalter 2001), visuo-spatial cognition (Cornish et al. 1998, 1999), and inhibition (Cornish et al. 1998, 1999). Disappointingly, there is an imbalance in the ratio of male to female studies with a greater proportion of research focused on the male phenotype as cited above. There is also a paucity of studies that have investigated cognitive signatures across both genders in the same research design. In the domains of attention and working memory, toddlers and children with FXS when compared to typically developing children have significant impairments in attention and memory functioning. An early study by Hooper et al. (2000) showed that children with FXS from 4 years of age display striking difficulties in attention and memory subscales of the Leiter International Performance Scale- Revised, a nonverbal assessment tool. In a series of more recent studies, Scerif et al. (2004) have demonstrated even earlier difficulties in the control of attention in children with FXS as young as 12 months of age (Scerif et al. 2004, 2007). These studies aimed at tracing developmental trajectories of attentional control in both children with FXS and in typically developing groups. While typically developing toddlers displayed gradual improvements in the accuracy with which they searched their visual environment, toddlers with FXS tended to perseverate and were unable to shift attention away from previously correct responses, regardless of their overall developmental level. These findings replicate the pattern of difficulties seen in older boys (7–12 years) (Wilding et al. 2002) and in young adult men (18–30 years) (Cornish et al. 2001b). Similar difficulties in attention switching in FXS girls (8–16 years) have also been reported (Kovar 1993). Thus, difficulties in perseveration and in shifting attentional focus are core deficits in FXS and appear to remain constant with age. In contrast, the ability to select relevant from irrelevant information (selective attention) is a relative strength at least in FXS males that continues to develop linearly with increasing chronological age (Cornish et al. 2007b). Compa- rable developmental studies in females are needed to understand the range of attention dysfunction and its relation with age and IQ. To date, however, the current findings underscore the importance of recognizing and treating early attention deficits that if left untreated will impact significantly across development and learning in both males and females. It is of note that a pervasive deficit in attentional control may account for the prevalence of specific impairments across other cognitive domains that also involve inhibition as a core component, for example, 222 N.J. Rinehart et al. the high incidence of repetitive speech seen in boys and girls with FXS (Cornish et al. 2004b). In the domain of memory, in boys there is evidence clearly pointing to relative strengths in long-term and short-term recall for meaningful information including memory for faces (Turk and Cornish 1998) and story recall (Munir et al. 2000) with performance at a level equivalent to typical children matched on developmental level (but not chronological age level). No equivalent published studies have been conducted in FXS girls. In terms of working memory (the ability to retain and manipulate information “online” over short periods which is crucial in guiding attention and behavior during the course of an activity), accumulating evidence points to a relative weakness in visuo-spatial working memory compared to verbal working memory (Munir et al. 2000; Cornish et al. 1999). For example, Munir et al. (2000) examined working memory performance in 25 boys with FXS aged 8–15 years, 25 boys with Down syndrome (trisomy 21) aged 7–15 years, and two groups (25 in each) of typically developing children matched to the syndrome groups on developmental level (mental age) and on chronological age. At first glance, the findings indicated general weaknesses across both verbal and visual memory skills that were not syndrome specific but suggestive of developmental delay. However, closer inspection revealed that the impairment of the FXS group relative to that of the DS group was significantly larger on tasks that tapped visuo-spatial memory skills than for tasks that tapped verbal memory skills. In comparison to FXS boys, few studies have addressed working memory in affected girls and those that have, focused almost exclusively on adult women. However, two recent studies by Mazzocco et al. (1998) and Kirk et al. (2005) highlight difficulties in working memory thresholds that also include a specific deficit in visual memory. Less than 53% of affected girls compared to 96% of typically developing females were able to recreate the gestalt of a design by memory even though they could correctly identify the object. This finding lends some support to a tentative hypothesis that visuo- spatial impairment may be a defining feature of the phenotype in both boys and girls irrespective of degree of intellectual impairment. However, one must show some caution here in giving the impression that visual memory is a global weakness in FXS. Variability especially in the female phenotype is inevitable, and studies of adult women have reported visual memory skills that are within the normal range (Mazzocco et al. 1993). In one of the few FXS studies to date to assess both males and females on the same cognitive measures, Cornish and Wilding (2006) found evidence of gender- specific FXS “signatures” whereby males and females of similar verbal mental age display different cognitive profiles in the domains of spatial cognition and lan- guage. FXS males as a group performed worse overall, followed by FXS females and then typically developing controls. When gender differences emerged, they were only within the FXS groups. Females were superior to males on tasks that tapped visuo-spatial skill, visuo-constructive skill, and articulation, but both gen- ders displayed comparable performance on tasks that involved visual perception such as gestalt integration and language comprehension. The pattern of gender differences in FXS represents a unique and important finding that highlights a Gender Differences in Neurodevelopmental Disorders 223 specific male weakness for skills that depend on visual and spatial construction of abstract, meaningless designs to form a whole, and for recall and construction of a familiar design. The fact that both tasks require relatively good visuomotor integra- tion for successful completion may be the key to understanding the fragile X male deficit. Similar gender-driven studies across other core domains (e.g., attention and working memory) would be of tremendous benefit in adding to our knowledge about the impact of gender in X-linked genetic disorders. 9 Autism and Fragile X Gender Difference Theories In FXS, genetic variation in the form of X-inactivation (when one of the two X chromosomes remains inactive and the other active) is seen as the major contributor to the broad range of cognitive deficits seen in females with FXS. This may also account for why in some females there is a significantly less impaired phenotype compared to their male counterparts who do not benefit from the protection of X- inactivation, and hence show greater severity. Explanations for the gender differences in autism are less clear. Skuse (2000, 2009) and Baron-Cohen (Baron-Cohen 2002; Baron-Cohen et al. 2005) have proposed the two main theories to account for the preponderance of males versus females diagnosed with autism. Skuse (2009) proposed that males are more vulner- able to autism by virtue of a single X chromosome. Based on parallels between the high male preponderance of autism and social skill deficits in monosomy in females (XO), known as Turner syndrome, Skuse’s theory suggests that a single X chromo- some could reduce the threshold at which symptoms of autism manifest. Females with a second X chromosome have protection from the impact of autosomally mediated genetic vulnerability by “its influence on the development, structure, and function of the social brain” (Skuse 2009). Skuse (2009) proposed that X-imprint- ing would lead to male preponderance irrespective of gender hormones. This theory is proposed to account for the overrepresentation of males diagnosed with neurop- sychiatric disorders, including ADHD, a disorder which like autism involves in social communication impairment (see a discussion of ADHD gender issues below) (Skuse 2000). The evidence about whether X-linked genes contribute to individual risk factors for autism is controversial (Gong et al. 2008). One of the main limitations of Skuse’s theory is that it cannot explain father-to-son transmission (Rutter 2005). Rutter

(2005) noted that if an imprinted gene of the X chromosome is responsible for an increased male liability, it is likely that it operates in all males rather than through variable allelic transmission. Rutter (2005) suggests that “epigenetic effects remain a possibility and it is possible that prenatal hormones interact with susceptibility genes, but this possibility can be investigated more satisfactorily once susceptibility genes have been indentified” (Rutter 2008). While Skuse’s theory discounts a role for male sex hormones in the etiology of autism, Baron-Cohen’s extreme male brain (EMB) theory (Baron-Cohen et al. 224 N.J. Rinehart et al. 2005; Baron-Cohen 2002) proposes that exposure to higher levels of fetal testoster- one (fT) may be an important causal factor in the etiology of autism, and could explain the male preponderance. The cognitive sequelae to increased testosterone in utero is hypothesized to be a “systemizing” cognitive style in males, characterized by focused learning of facts and rules of systems. Reduced testosterone in females is thought to result in a more “empathetic” cognitive style. Earlier empirical evidence to support the EMB comes from the finding that individuals with autism have a lower second to fourth finger length ratio (2D:4D); this finger length ratio is a gender dimorphic finding which has been attributed to high levels of prenatal testosterone in the male brain. In other studies to support the EMB, Baron-Cohen has reported that fT is inversely related to eye contact, vocabulary, empathy, and embedded figures performance. The most recent data to support the EMB theory were reported by Aueyung et al. (2009) who followed up a cohort of 235 children, where amniotic measures of fT were sampled in the course of clinical screening to detect genetic risk factors. When the children reached 6–10 years of age, autistic traits were assessed using parent report on standardized instru- ments. A positive relationship between high “autistic symptom” scores and fT was reported. While the EMB has been referred to as the only theory of autism to provide a link between etiology, neuropsychology, and the neural basis of autism (Klin 2009), there have been several criticisms of its empirical evidence base. Skuse (2009) notes that data supporting the EMB do not make it clear whether fT actually increases the risk for a clinical diagnosis of autism, or whether fT merely reduces the threshold for detection of autistic-like symptoms. Barbeau et al. (2009) argue that the link between autism and an exaggerated male behavioral profile is prob- lematic because individuals with autism actually do better than non-autistic indi- viduals on some tasks considered to be measures of female traits, and which are not associated with high testosterone levels. For example, Barbeau et al. point out that the performance of a group of individuals with autism on a lexical knowledge task was more similar to the performance typically seen in females than males (Walenski et al. 2008). Barbeau et al. (2009) also argues that testosterone favors right hemisphere development, which should result in superior global processing ability; however, it is well documented that individuals with autism show a prefer- ence for processing “local” details. Barbeau et al.’s (2009) main critique of Aueyung et al.’s (2009) data linking autistic traits to fT is that the traits being measured cannot be considered “autistic since the children are not autistic, they are typical traits found in typical individuals at different levels, together with all the normal behavioral traits” (p. 27). More broadly, perhaps the most significant criticism of the EMB is the issue of testosterone levels affecting cognitive, but not physical traits in individuals with autism (Barbeau et al. 2009). There are some indirect links between testosterone-related medical conditions and females with autism; for example, Baron-Cohen et al. reported that, compared to controls, significantly more women with autism reported via a medical screening instrument a range of testosterone-linked conditions, including hirsutism, irregular menstrual cycle, polycystic ovary syndrome, severe acne, epilepsy, and a family history of Gender Differences in Neurodevelopmental Disorders 225 ovarian, uterine, and prostate cancers, tumors, or growths. Furthermore, signifi- cantly more mothers of females with autism reported severe acne, breast and uterine cancers, tumors, or growths, and a family history of ovarian and uterine cancers, tumors, or growths. Further research is needed to investigate whether these elevated physical and medical risks are directly related to serum levels of testosterone, and not some other hormonal risk factor. 10 Summary This chapter highlights a new focus in the neurodevelopmental literature: gender- specific research. To paraphrase Thompson et al. (2003), “sex” is beginning to “matter” in our understanding of children with neurodevelopmental disorders, the two most common being autism and FXS. There is evidence that the clinical presentation, cognitive profile, and neurobiological trajectory which characterizes males and females with neurodevelopmental disorders are different. Our under- standing of how these differences emerge is not yet clear, although biological maturation rates, sex hormones, and psychosocial factors all play a role. The clinical diagnosis, educational and mental health management plans for girls with neurodevelopmental disorders will necessarily differ from that which is currently prescribed for males, but to date there is no empirical evidence available to indicate what gender-specific management plans should entail. The findings which suggest that girls with autism have more significant fronto-striatal executive impairment and may show greater deterioration in their mental health postpuberty may flag a need for increased psychiatric/psychological review and psychoeducation for par- ents, leading up to this critical developmental period. The lack of gender-specific research in the neurodevelopmental disability field is perhaps in, and of itself, a contributing environmental “risk” factor for girls. To illustrate, while psychoeduca- tion is the front-line treatment for children with neurodevelopmental disorders, current information available to parents is based on research conducted with predominately male samples, some of which is not (according to parent reports) directly applicable or salient to girls with autism. This may delay the assessment process by invoking the “wait and see” method. The lack of salient information which informs the different ways autism may manifest in girls may complicate the subsequent grieving and adjustment periods for families. Autism is often referred to as a “silent disability”; for girls, this silence equates to a greater risk for under- diagnosis, misdiagnosis, and reduced opportunities for considering gender-specific interventions. The EMB theory is currently suggested to be the most comprehensive explana- tion available for the male preponderance of autism; while there is a growing body of research to support the links between fT and “autistic symptoms” in males with autism, it remains to be seen whether the clinical picture for girls with autism is really that of an “extreme male brain” or whether it is that of a “less extreme female brain.” The complex pattern of gender differences for males and females affected 226 N.J. Rinehart et al. by autism would call for future theoretical accounts to perhaps be gender-neutral, or based on the chromosomes involved, as is the case with FXS and Skuse’s X- imprinting theory. Future new discoveries about the “nature versus nurture” effects of gender in the context of neurodevelopmental disorders will have broader impli- cations for how we understand the causes of gender differences in childhood and adolescent psychiatry. 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The Impact of Gender on Antidepressants John J. Sramek and Neal R. Cutler Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 2 Gender Differences in the Pathogenesis of Depression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 3 Gender Differences in Response to Antidepressants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 3.1 Pharmacokinetic Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 3.2 Female Reproductive Hormones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 3.3 The Role of Menopause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 Abstract There is a large body of literature debating whether and how gender affects the metabolism, side-effect profile, and efficacy of antidepressants. Gender differences in antidepressant pharmacokinetics and efficacy profiles have been attributed to not only anatomic and physiological differences between the sexes, but also behavioral factors, comorbid disorders, and gender-specific conditions, such as pregnancy and menopause. Despite the large body of research on this topic, few definitive conclusions regarding effects of gender on antidepressant treatment exist, and much of this research is incomplete, contradictory, or not fully used to optimize the administration of antidepressants and the response to treatment. This chapter will review the latest research on gender-specific effects of antidepressant treatment, focusing on the overall, gender-related differences in efficacy, metabo- lism, and side-effect profile of antidepressants, and how these differences can be used to better optimize treatment of depression in a clinical setting. Keywords Antidepressant
Depression
Efficacy
Estrogen
Female
Gender
Hormones
Male
Menopause
Metabolism
Pathogenesis
Phamacokinetics
Sex
SSRI
TCA J.J. Sramek (*) and N.R. Cutler Worldwide Clinical Trials, Inc., 401 N. Maple Drive, Beverly Hills, CA 90210, USA e-mail: jsramek@wwctrials.com, neal.cutler@wwctrials.com J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 231 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010_118, # Springer‐Verlag Berlin Heidelberg 2011, published online 4 March 2011 232 J.J. Sramek and N.R. Cutler 1 Introduction There is a large body of literature debating whether and how gender affects the metabolism, side-effect profile, and efficacy of antidepressants. Gender differences in antidepressant pharmacokinetic and efficacy profiles have been attributed to not only anatomic and physiological differences between the sexes, but also behavioral factors, comorbid disorders, and gender-specific conditions, such as pregnancy and menopause. For example, gender-related variance in body fat, hormone levels, liver metabolism, gastric properties, and blood flow has been shown to affect the absorption, distribution, metabolism, and elimination of a drug. In addition, behaviors such as smoking and alcohol intake, typically more prevalent among men, may also influence the pharmacokinetics of antidepressants. Pregnancy andmenopause, as well as concomitant, female-specific medications, such as birth-control treatment and hormone therapy, can have an effect on the disposition and dose requirement of antidepressants. Finally, the clinical presentation, prevalence, and resiliency of the depression itself, as well as the existence of comorbid disorders such as anxiety disorder, often have gender-specific components that

may influence the treatment of the disorder and the response of patients to medication. Despite the large body of research on this topic, few definitive conclusions regarding effects of gender on antidepressant treatment exist, and much of this research is incomplete, contradictory, or not fully used to optimize the administration of antidepressants and the response to treatment. This chapter will review the latest research and literature on gender-specific effects of antidepressant treatment, focusing on the overall, gender-related differences in efficacy, metabolism, and side-effect profile of antidepressants, and how these differences can be used to better optimize treatment of depression in a clinical setting. 2 Gender Differences in the Pathogenesis of Depression Women are at least twice as likely as men to suffer from depression (Weissman and Klerman 1977; Weissman et al. 1993). This holds true across the spectrum of depressive disorders, including atypical depression, unipolar depression, dysthy- mia, and seasonal affective disorder (Rapaport et al. 1995; Lucht et al. 2003; Leibenluft et al. 1995). These differences have been found in every country surveyed (Weissman et al. 1996) and across all age groups (Kessler et al. 1993). In the USA, the national lifetime risk of major depression is 21% in women versus 13% in men (Kessler et al. 1994). Greater incidence of depression in females appears to be linked to a higher first onset rate (Kessler 2003). Symptom presenta- tion is also typically more severe in females. Depressed women are more likely to experience chronic or recurrent depression than depressed men, with an earlier age of onset and poorer quality of life (Kornstein et al. 2000b). In addition, depressed women tend to have more weight gain, anxiety, and physical symptoms than The Impact of Gender on Antidepressants 233 depressed men (Frank et al. 1988; Young et al. 1990; Angst and Dobler-Mikola 1984; Williams et al. 1995), although a study of depressed adolescents found younger girls tended to lose weight (Baron and Joly 1988). Depressed women also experience more crying, guilt, and body image dissatisfaction (Wilhelm et al. 2002), while depressed men tend to experience more work inhibition, health concerns, and social withdrawal (Vredenburg et al. 1986). The reasons for these dramatic differences between the sexes are still unknown, but many theories exist. Since gender differences in depression prevalence do not typically emerge until adolescence, studies have suggested that female’s greater susceptibility may be tied to increases in the female reproductive hormones estro- gen and progesterone at puberty (Nolen-Hoeksema 1990). Fluctuations in these female hormones have been suggested to make females more susceptible to both depression and anxiety (Seeman 1997), and women may experience hormonal triggers of depressive episodes tied to reproductive events (Parry 1989). In fact, numerous studies have found variations in hormonal levels tied to increases in depressive symptoms in women undergoing puberty, menstruation, and menopause (Schmidt et al. 2004; Freeman et al. 2004). In support of this theory, the postmeno- pausal incidence of depression in women (when reproductive hormones stabilize) was found to be similar to that of men (Bebbington et al. 2003). There is even evidence that circadian rhythms interact with reproductive hormones and confer susceptibility to depression in some women during premenstrual dysphoric disorder (PMDD), pregnancy, and the postpartum period (Parry and Newton 2001). Differences in monamine functioning and processing may also contribute to the gender differences in the prevalence of depression. A recent study investigated tryptophan depletion in women and men who were currently in remission from a DSM-IV-defined major depressive episode. Depletion of the monoamine trypto- phan produces a transient reduction in serotonin transmission and can be used for inducing depressive episodes in formerly depressed patients. This procedure triggered significantly greater depressive symptoms in women versus men, suggest- ing depressive vulnerability may be related to gender differences in monoaminergic function (Moreno et al. 2006). In support of this theory, positron emission tomog- raphy (PET) showed serotonin synthesis was 48% lower in females compared with males following tryptophan depletion (Nishizawa et al. 1997). Several studies suggest that depression manifests itself with fundamentally different characteristics in males versus females. For example, young women have been found to experience more negative self-evaluation and rumination than young men, making them more susceptible to depression, and causing them to experience deeper and more prolonged depressive episodes than men (Hankin and Abramson 2001; Nolen-Hoeksema et al. 1999). In addition, changes in brain function induced by depression and antidepressants have been found to be different between the sexes. Women with a history of childhood depression exhibit mid- frontal alpha wave suppression on the opposite side of the brain than men (Miller et al. 2002), and depressed women who respond to the antidepressant fluoxetine have lower purine levels compared to non-responders than men (Renshaw et al. 2001). 234 J.J. Sramek and N.R. Cutler In addition, several neurotransmitter systems associated with mood and depres- sion show altered levels in males and females. Here we remind the reader of the large body of evidence correlating dysfunction of the norepinephrine (Delgado and Moreno 2000; Anand and Charney 2000; Lambert et al. 2000) and serotonergic systems (Owens and Nemeroff 1994) with the pathogenesis of depression, particu- larly the depletion of both of these neurotransmitters. The prolongation of serotonin (5-HT) and norepinephrine (NE) in the synaptic cleft is the mechanism of action for two major classes of antidepressants, appropriately named selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). Different concentrations of serotonin and its metabolites have been found in the brains of same-aged males and females (Legato 1997). Baseline serotonin production was found to be 52% higher in the brains of young adult men compared to young adult women when measured with a PET radioligand (Nishizawa et al. 1997), and this was supported by another recent PET study (Sakai et al. 2006). Older, postmenopausal women were found to have lower levels of serotonin and cortisol than older men (Young 1995), and a percentage of depressed women showed lower-than-normal norepinephrine activity for their age (Halbreich and Lumley 1993). Serotonin metabolism and the serotonin metabolite 5HIAA were found to be elevated in females versus males (Young et al. 1980), possibly related to higher availability of the serotonin transporter 5-HTT in women (Staley et al. 2001). In addition, the serotonin 5-HT1A receptor subtype, which is implicated in the pathogenesis of depression, shows a significant decrease in binding potential with age in males but not females (Meltzer et al. 2001). Brain levels of serotonin and norepinephrine show greater age-related changes in females com- pared tomales (Legato 1997). Platelet 5-HT and levels of the serotonin metabolite 5- HIAA were significantly higher in older women compared to younger women (89.41 ng/108 platelet for younger vs. 112.9 for older; 1.20 for younger vs. 2.19 for older, respectively) (Kumar et al. 1998). The dopaminergic system has also been found to play a role in the pathogenesis of depression, and a large body of recent literature has focused on altering brain levels of dopamine (DA) as a therapeutic intervention in depression. DA turnover has been shown to be reduced in depressed patients (Brown and Gershon 1993), and chronic antidepressant treatment can alter DA transmission (Dhir and Kulkarni 2007). Homovanilic acid (HVA), a major metabolite of DA, has been found to be reduced in the CSF (Roy et al. 1985; Hamner and Diamond 1996) and plasma (Lambert et al. 2000) of depressed patients. Neuroimaging and histopathological studies have found D2/D3-receptor binding to be increased, and dopamine trans- porter (DAT) binding to be decreased, in patients suffering from major depressive disorder (MDD) in comparison to healthy controls (Klimek et al. 2002; D’Haenen and Bossuyt 1994; Shah et al. 1997; Meyer et al. 2001). DA may also promote neurotrophic processes in the adult hippocampus (Guiard et al. 2009), and is the target for new classes of antidepressants, such as triple monoamine reuptake inhibitors and dopamine agonists (Rakofsky et al. 2009). Gender effects appear to play a role in the dopaminergic system as well. Neuroimaging studies have suggested that women have a higher synaptic The Impact of Gender on Antidepressants 235 concentration of dopamine in the striatum than men. They also show that women have a higher striatal dopamine synthesis capacity than men, and that age decreases this capacity in men more than in women (Laakso et al. 2002). Preclinical studies have suggested that female sex hormones enhance presynaptic dopamine turnover (Shimizu and Bray 1993; Xiao and Becker 1994).Women experience reduced striatal dopamine release in response to amphetamines than men (Munro et al. 2006). In addition, women in the luteal phase of the menstrual cycle, which is associated with high levels of progesterone, display reduced responses to amphetamine and cocaine (inhibitors of DA reuptake) compared to men (Sofuoglu et al. 2004; White et al. 2002). Females have been shown to exhibit higher levels of DAT activity than males (Dluzen and McDermott 2008), supported by preclinical studies suggesting higher DAT density in female rats versus male rats (Rivest et al. 1995). In contrast, male rats exhibit higher production and turnover of the D1 and D2 dopamine receptors (although both genders show comparable receptor density) (Andersen et al. 1997). While numerous and varied gender differences have been reported in the seroto- nergic, dopaminergic, and norepinephrine systems, the significance of these changes, and how they interact to increase or decrease the susceptibility of each gender to depression, requires further study. Depression in females may also correlate with reductions in reproductive hor- mones due to menopause. Surgical menopause has also been found to increase depressive symptoms (Shifren and Avis 2007). In addition, oophorectomized females who received estrogen replacement therapy (ERT) reported diminished anxiety and depression compared to oophorectomized females not receiving ERT (Nathorst-Boos et al. 1993). While suggestive of a palliative role for estrogen in the treatment of depression, the evidence for this remains ambiguous, as other studies have not shown postmenopausal women to be at an increased risk for depression (Winokur 1973). 3 Gender Differences in Response to Antidepressants Despite decades of research on sex-related differences in antidepressant treat- ment, the consensus is still out on whether such a difference exists, and if so, whether it is dependent on the class of antidepressant, menopausal state, BMI index, hormonal interactions, or PD/PK characteristics, among other variables. There are numerous studies that have shown significant gender differences in regards to the efficacy of certain antidepressants (see Table 1 for a list of studies showing gender effects). For example, several studies have found a significantly greater therapeutic response among men compared to women after taking the tricyclic antidepressant (TCA) imipramine (Dawkins and Potter 1991; Hamilton et al. 1996; Kornstein et al. 2000a; Frank et al. 1988). Another study found that women had more therapeutic benefit with the SSRI sertraline versus the TCA imipramine, whereas men responded similarly to both antidepressants 236 J.J. Sramek and N.R. Cutler Table 1 Studies finding gender-based efficacy differences with antidepressants Reference Drug type Study type Subjects Results Haykal and Akiskal (1999) SSRIs, TCAs TCA-type antidepressants or 25 male and 17 female primary Females responded better than fluoxetine dysthymic patients males to SSRIs Kornstein et al. (2000a, b) SSRIs, TCAs 12-week double-blind trial with 235 male and 400 female Females responded better to sertraline or imipramine outpatients with chronic SSRI sertraline, males major depression or double responded better to TCA depression imipramine; differences observed primarily in premenopausal females Martenyi et al. (2001) SSRIs, TCAs 6-week, double-blind trial of 105 male and female depressed Females in their reproductive SSRI (fluoxetine) and a patients period were more norepinephrinergic TCA responsive to SSRIs than (maprotiline) norepinephrinergic TCAs Quitkin et al. (2001) TCAs, MAOIs, SSRIs 20-year review of 8 placebo- 1,746 depressed patients Older females had superior controlled antidepressant between 18 and 65 response to TCAs than trials and 1 open-label study younger females; females had statistically superior response to MAOIs than males Khan et al. (2005) SSRIs, SNRIS Review of 15 randomized, 323 depressed patients Females had a significantly placebo-controlled trials for greater response than males sex differences in to SSRI and (to a lesser antidepressant efficacy extent) SNRI treatment Berlanga and Flores-Ramos SSRIs, SNRIs 8-week, double-blind clinical 86 depressed patients Premenopausal females (2006) trial for gender differences (48 females, 38 males) respond better than males to in SSRI citalopram and 18–40 years old serotonergic antidepressants SNRI reboxetine Young et al. (2009) SSRI 12–14-week study of 1,043 male and 1,833 female Females

have a better response citalopram patients with single or to the SSRI citalopram than recurrent nonpsychotic males MDD The Impact of Gender on Antidepressants 237 (Baca et al. 2004). In addition, a study of atypical depression found monoamine oxidase inhibitors (MAOIs) were superior to TCAs in women, while TCAs were superior to MAOIs in men (Davidson and Pelton 1986). Several studies also suggest women may respond better to SSRIs than men (Kornstein et al. 2000a; Thase et al. 2000; Martenyi et al. 2001; Haykal and Akiskal 1999; Khan et al. 2005; Sagud et al. 2002; Young et al. 2009), although the results of one of these studies has been disputed (Quitkin et al. 2001). A recent study found that younger women exposed to the SSRI fluvoxamine not only had a better response than men, but also a better response than older women (>44 years old) (Naito et al. 2007). In contrast, there are a large number of studies that have detected no gender differences in regards to the efficacy of various antidepressants, even when examining the same class of antidepressants as the studies which found gender differences (see Table 2 for a list of studies showing no gender effects). For example, a study found the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine and SSRIs produced a comparable response in both men and women (Entsuah et al. 2001). A large, retrospective study of TCAs, MAOIs, and the SSRI fluoxetine found no difference based on sex or menopausal status on drug efficacy (Quitkin et al. 2002), and additional studies found women did not respond preferentially to SSRIs (Thiels et al. 2005), nor did men respond prefer- entially to TCAs (Parker et al. 2003). Adding fuel to this argument, Hildebrandt et al. (2003) found no effect of gender on therapeutic outcome in patients treated with the TCA clomipramine, nor with the SSRIs citalopram and paroxetine, nor with the MAOI moclobemide. A meta-analysis of 30 randomized placebo- controlled trials of imipramine or amitriptyline also found no effect of gender on TCA efficacy(Wohlfarth et al. 2004). While it is unclear why such contradictory data exist, there are numerous methodological issues which could explain such differences. For one thing, these studies did not all use the same criteria for determining what constituted a significant response to treatment. For example, one study used a paired t-test to compare total HAMD17 baseline to posttreatment scores (Martenyi et al. 2001); another study required a 50% or greater decrease in HAMD21 scores to indicate a significant response to treatment (Entsuah et al. 2001). In addition, the varied ages of the female patients in these studies could also play a role, as older, postmenopausal women have very different levels of female sex hormones than younger, premenopausal women, and these hormones may affect antidepressant efficacy and metabolism. Other potential sources of variability include the clinical presentation of the depressed patients (i.e., typical versus atypical), whether the patient was treated with antidepressants previously, the various drugs and doses used across studies, and how well the patient adhered to the treatment regimen. In addition, some studies were prospective, while others were a meta-analysis of large data pools. Better-controlled studies are needed to account for these numerous variables and tease out any influence of gender on antidepressant efficacy. 238 J.J. Sramek and N.R. Cutler Table 2 Studies finding no gender-based efficacy differences with antidepressants Reference Drug type Study type Subjects Results Entsuah et al. (2001) SSRIs, SNRIs Meta-analysis of 8 comparable 2,045 patients with major Males and females have double-blind, active- depression or major comparable responses to controlled, randomized depressive disorder, aged SSRIs and SNRIs across SSRI or venlafaxine clinical 18–83 years various age groups trials Hildebrandt et al. (2003) SSRIs, TCAs, MAOIs Review of 3 Danish double- 292 inpatients (96 males, 196 No relationship between blind randomized, females) with major and plasma concentrations, controlled trials predominantly melancholic gender, and therapeutic depression outcome Wohlfarth et al. (2004) TCAs Review of 30 randomized, 3,886 patients (1,555 males and Tricyclic antidepressant placebo-controlled trials of 2,331 females) with response is independent of antidepressant efficacy depression gender Thiels et al. (2005) SSRIs Review of data from a 6-month 1,594 male and 3,858 female No gender difference in side- prospective sertraline depressed patients effects, treatment utilization observation termination, or treatment study response to SSRI Pinto-Meza et al. (2006) SSRIs 6-month follow-up study of 242 females (95 in their No gender differences were antidepressant treatment menopause) and 59 males observed in treatment with a SSRI (citalopram, with major depression response, depression fluoxetine, paroxetine, or severity, and sertraline) symptomatology The Impact of Gender on Antidepressants 239 3.1 Pharmacokinetic Differences Women and men have been found to exhibit different pharmacokinetic (PK) profiles of antidepressants. Different PK profiles stem from many different sources, including gender-related variance in body weight, plasma volume, gastric acid production, gastric emptying time, plasma protein levels, enzyme activity, drug transporter function, and drug clearance rates, among others. Women have been shown to have higher plasma levels (Hamilton et al. 1996; Preskorn and Mac 1985) and lower clearance of TCAs (Gex-Fabry et al. 1990). This may partially be attributed to the fact that women have a higher percentage of adipose tissue and body fat compared to men. Antidepressants are lipophilic and have a strong affinity for adipose tissue, typically resulting in a greater volume of drug distribution in women (Yonkers and Brawman-Mintzer 2002; Yonkers et al. 1992). Lipophilic drugs tend to have a greater distribution in women, while water soluble drugs tend to have a greater distribution in men. In addition, women tend to secrete less gastric acid and empty the contents of their stomach more slowly than men, and have slower gastric motility in the presence of female sex hormones, resulting in reduced breakdown and clearance of antidepressants (Hutson et al. 1989; Young et al. 2009). A review study summarized data supporting sex differences in the activity of various antidepressant-metabolizing enzymes, although little research exists into how these differences might translate into differences in clinical efficacy (Yonkers and Brawman-Mintzer 2002). Several studies found lower levels of the drug transport protein P-glycoprotein in females, which could result in altered bioavailability of certain drugs in women (Lan et al. 2000; Schuetz et al. 1995). These differences were not observed in a subsequent study, suggesting that further investigation of this transport protein is necessary (Kim et al. 2001). Studies have also found that estrogen affects the binding of metabolic enzymes to certain glycoproteins, which could potentially affect drug metabolism if those drugs were composed of glycoproteins or glycoprotein homologues (Succari et al. 1990). The cytochrome P450 (CYP450) enzyme superfamily is one of the major drug metabolizing systems in humans, and several of its constituent parts exhibit gender differences which could contribute to observed gender differences in the PK profile of antidepressants. The metabolic enzyme CYP3A4 is highly expressed in the liver and has the largest range of substrates of all CYP enzymes, making it one of the most important enzymes for breaking down xenobiotics. It plays a major role in the metabolism of many of the drugs taken into the body, including numerous SSRIs (including citalopram, escitalopram, fluoxetine, and sertraline) and TCAs (includ- ing amitriptyline, imipramine, and clomipramine). Drugs that are substrates of CYP3A4 have often been found to clear faster in women than in men (Meibohm et al. 2002), which may be due to higher observed CYP3A4 enzymatic activity in women than in men (Hunt et al. 1992; Schmidt et al. 2001). On the other hand, drugs that are substrates of CYP2D6, another major metabolizer of xenobiotics, including the TCAs desipramine (Abernethy et al. 1985) and mirtazapine (Timmer et al. 2000), 240 J.J. Sramek and N.R. Cutler have often been shown to clear faster in men than in women (Labbe et al. 2000). Substrates of CYP1A2 have generally been found to clear faster in men than in women (Ou-Yang et al. 2000; Ereshefsky et al. 1991; Bruno et al. 1997), although there are studies that have shown the exact opposite (Nafziger and Bertino 1989). In addition, studies have shown that substrates of CYP2E1 also clear faster in men than in women (Lucas et al. 1995; Kim and O’Shea 1995). In addition to the CYP450 system, there are many other metabolic enzymes that display gender differences in function, and these enzymes also contribute to the PK profile of xenobiotics. For example, substrates of the enzymes thiopurine methyl transferase, glucuronidation, dihydropyrimidine dehydrogenase, UDP-gluronosyl transferase, and catechol-O-methyl transferase all show greater clearance in men than in women (Franconi et al. 2007). On the other hand, substrates of xanthine oxidase show greater clearance in women than in men (Bock et al. 1994). Determining how these numerous (and often contradictory) gender-based differ- ences in metabolic enzymes and functions combine to affect the breakdown and distribution of antidepressants is an extremely complex task. It remains to be determined exactly what the clinical significance these differences are in regards to antidepressant efficacy. Most likely this effect will vary not only by the class of antidepressant, but also by the individual structure of each unique antidepressant compound. 3.2 Female Reproductive Hormones Levels of estrogen and other female reproductive hormones have been suggested to play a role in the pathogenesis of depression and the efficacy of antidepressants. This has been evidenced, in part, by the difference in susceptibility to depression, and the difference in response to antidepressants, in women before and after menopause – an event associated with a dramatic drop in reproductive hormone levels. Premenopausal women respond better to certain classes of antidepressants than postmenopausal women. Likewise, depressed, postmenopausal women receiv- ing ERT in combination with a SSRI showed better clinical response than depressed, postmenopausal women receiving the SSRI alone (Schneider et al. 1997). A 6-week, open-label, naturalistic study looked at the response of premeno- pausal and postmenopausal women with MDD to various antidepressants, including SSRIs, SNRIs, and TCAs. The study found that postmenopausal status predicted a poor response to antidepressants, and this also correlated with high levels of follicle-stimulating hormone (FSH) (Pae et al. 2009). Several studies have found both FSH and luteinizing hormone (LH) to be elevated in postmenopausal depres- sion (Harlow et al. 2003; Abe et al. 1985; Freeman et al. 2006). Supporting this finding, improvements in depressive symptoms in peri-menopausal women have been correlated with decreases in FSH levels (Daly et al. 2003). Levels of estradiol (E2) have also been reported lowered in depressed premenopausal and peri-menopausal women (Harlow et al. 2003; Young et al. 2000). The Impact of Gender on Antidepressants 241 Female reproductive hormones have effects that may interfere with or enhance the efficacy of antidepressants. For example, progesterone and estrogen have been found to modulate neurotransmitter synthesis, release, and reuptake – characteris- tics that many antidepressants also modulate (Frackiewicz et al. 2000). Estrogen has also been found to increase new dendritic spine formation and regulate neuro- tropic factors (Bryant et al. 2006). In addition, progesterone in the luteal phase has been found to slow gastric emptying, potentially modifying an antidepressant’s pharmacokinetic properties (Yonkers et al. 1992). Estrogen has been found to interact with the serotonergic system, which is the target of many antidepressants, including SSRIs and SNRIs. Serotonergic agents have been found to be more potent in the presence of estrogen (Halbreich et al. 1995). In addition, the serotonin releaser, fenfluramine, had a greater effect on postmenopausal women taking ERT than ERT-naive, postmenopausal women (van Amelsvoort et al. 2001). 3.3 The Role of Menopause Studies looking at menopause and antidepressants tend to support the theory that estrogen and other reproductive hormones enhance antidepressant efficacy. For example, a recent study looked at 242 depressed women (95 in menopause), and 59 depressed men beginning antidepressant treatment with an SSRI (citalopram, fluoxetine, paroxetine, or sertraline) from 16 primary care centers over the course of 6 months. The study found that menopause, characterized by significantly reduced female reproductive hormones (including estrogen), seems to negatively affect the SSRI treatment response of depressed women (Pinto-Meza et al. 2006). Another study examined 115 female outpatients with MDD (divided into premenopausal and postmenopausal status), as well as 86 age-matched male outpatients, before and after 8 weeks of treatment with the SSRI nefazodone or venlafaxine. The study found that women are more responsive to SSRIs during their reproductive period than during their menopausal period (Grigoriadis et al. 2003). Another study looked at

the response of 86 depressed male and premenopausal female patients (18–40 years old) to the SSRI citalopram and the serotonin-norepinephrine reuptake inhibitors (SNRI) reboxetine, in an 8-week, double-blind clinical trial. The study concluded that premenopausal women respond better than men to serotonergic antidepressants, further suggesting that female gonadal hormones such as estrogen may have an enhancing effect on antidepressant efficacy (Berlanga and Flores-Ramos 2006). These results are far from conclusive, as estrogen may function as a general mood-enhancer, independent of its hypothesized role as an antidepressants- enhancer. Estrogen given to peri-menopausal women not on antidepressants was found to be an effective treatment for depression (Soares et al. 2001). In addition, abrupt interruption of ERT in women aged over 40 with recurrent depression can quickly induce a new depressive episode (Stewart et al. 2004). On the other hand, numerous studies have not found a higher risk for depression in women 242 J.J. Sramek and N.R. Cutler during their postmenopause phase, when reproductive hormones drop significantly (McKinlay et al. 1987; Avis et al. 1994). In support of this, another study found that estrogen alone was ineffective at relieving depression in most postmenopausal women (Morrison et al. 2004). Low LH levels also correlate and may be predictive of better antidepressant response in postmenopausal women (Zanardi et al. 2007). Serotonin levels have been found to be inversely correlated with LH levels (Carretti et al. 2005). Since low LH levels imply higher serotonin levels, this may provide a more potent substrate for antidepressants whose mechanism of efficacy is dependent upon the availability of serotonin (such as SSRIs and SNRIs). Low LH levels also correlate to hyperactivity of the hypothalamic–pituitary–adrenal (HPA) axis (Vadakkadath Meethal and Atwood 2005; Swaab et al. 2005), which represents the complex interactions between these organs that is essential in mood regulation, and is disrupted in MDD (Pariante 2003). As antidepressants typically work by reducing HPA activity, patients with low LH levels may have a hyperactive HPA axis, and are therefore good candidates for experiencing symptom improvement via antidepressant treatment (Holsboer and Barden 1996; Holsboer 2000). The menstrual cycle also may play a role in attenuating antidepressant efficacy. The menstrual cycle can affect gastric motility, as fluid retention may result in diluted plasma levels of a drug (Yonkers et al. 1992). In addition, fluctuating levels of female sex hormones during the menstrual cycle may interact in complex ways with antidepressant metabolism. All of these factors contribute to the complex pharmacokinetic profile of antidepressants in women. More research is required to understand how each of these factors work together to produce observed gender differences in the efficacy of many antidepressants. 4 Conclusion Despite decades of research into the effect of gender on depression pathogenesis and antidepressant efficacy, the consensus is still out on what these effects are, how these effects are produced, and in some cases, whether these effects exist at all. While many studies have found a higher incidence of depression in females, with a different array of symptoms and severity of symptom presentation, the reasons for these differences remain unknown. Likely, female sex hormones are at least partially involved, as periods of fluctuating levels of estrogen and progesterone have been linked to increased incidence of depression, such as during puberty and the transition to menopause. Differences in monoamine function, neurotransmitter metabolism, and even innate brain structures may also play a role in depression susceptibility, as numerous studies have identified an array of gender-specific differences in structures implicated in the pathogenesis of depression. These systems are thought to play a role in producing gender-specific differences in antidepressant therapy, although their discrete role is far from clear, and even whether such gender differences exist remains controversial. There are almost an The Impact of Gender on Antidepressants 243 equal number of published studies showing gender differences, and no gender differences, in the efficacy profile of identical classes of antidepressants. This contradiction may be due to numerous factors, including methodological differ- ences between studies in the measurement of a statistically significant treatment response. A better consensus exists regarding gender differences in antidepressant metab- olism. Sex-specific variance has been identified in numerous pharmacokinetic components, including plasma volume, gastric acid production, gastric emptying time, plasma protein levels, metabolic enzyme activity, drug transporter function, and drug clearance rates, among others. In addition, a large body of literature exists examining the effects of female hormones on the efficacy of antidepressants. For example, numerous studies suggest that estrogen has an enhancing effect on antidepressant efficacy, as evidenced by the poorer response of postmenopausal women to a variety of antidepressants when compared with premenopausal con- trols. This finding has direct therapeutic implications for treating depressed, post- menopausal women. On the other hand, lower levels of LH have been correlated with improved antidepressant efficacy. 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Index A prevalence, 210, 215 Acetylcholine (ACh) release, 58 Aversion/aversive, 190, 192, 193 monitoring, 59–60 physiological role, 58–59 sex differences, 61–62 B time-dependent, 60–61 Bipolar disorder, 175–176 Activity-based rodent model of anorexia oestradiol effects, 178–179 nervosa (ABA), 198, 199 treatment, 180–182 Adrenocorticotropin hormone (ACTH), Body dysmorphism, 193 198, 202 Body image, 191, 194 Allopregnanolone (ALLO), 82, 86–88 Brain imaging, 219 Alzheimer’s disease, 66–67 Amygdala, 105 Androgen C androgen receptor (AR), 9 CA3 region, 48 5a-dihydrotestosterone, 9 Catechol-O-methyltransferase Anhedonia, 106 (COMT), 120–122 Anorexia nervosa (AN), 189–204 activity, 129 ANOVA interaction, 123 enzyme activity, 131 Anterior cingulate cortex (ACC), 190, genotype, 128 193, 194 mRNA, 130 Antidepressants, 111, 200, 201, 203, 231–243 protein, 131 Antipsychotic, 199, 200, 203, 204 rs737865, 128 Anxiety, 210, 214, 217, 218 SNPs, 128 Anxiety-related phenotypes, 129 Val158, 128 Associative learning, 102 Caudate, 197 Attention, 210, 211, 213, 217, 219–222 Central nervous system (CNS), 2 Attention deficit hyperactivity disorder Choline acetyltransferase immunoreactive (ADHD), 213, 214, 218, 223 (ChAT-ir), 63 Autistic disorder Cholinergic neurons, 63 contrast with asperger disorder, 211, 212, Chronic mild stress (CMS), 105 215, 218 Chronic stress, 47 differential diagnoses, 223 Chronic treatment, 32 gender difference explanation, 218, 222 Citalopram, 19, 20 gender differences, 210, 218, 225 Clinical trials, 238 neurobiology, 210, 214, 224 Clomipramine, 111 post-puberty, 219 Cognition, 218–222 J.C. Neill and J. Kulkarni (eds.), Biological Basis of Sex Differences in Psychopharmacology, 251 Current Topics in Behavioral Neurosciences 8, DOI 10.1007/7854_2010, # Springer‐Verlag Berlin Heidelberg 2011 252 Index Cognition, 218–222 (cont.) Estrone (E1), 3 classical and operant conditioning, 45–47 Estrous cycle, 82, 84–85 object recognition tasks, 39–43 Executive dysfunction, 219 social recognition, 45 Extracellular signal-regulated (ERK), 61 spatial maze paradigms, 43–44 Extreme male brain, 223, 225 Cognitive, 99 Eyeblink classical conditioning, 102 Cognitive decline, 220 Conduct disorder, 225 Contamination, 190, 192–195 F Corticosterone, 100, 108 Females, 189–204 Corticotropin-releasing hormone (CRH), Female sexual behaviour 191, 196 Flinders sensitive line, 111–112 CYP7B1, 8 Fluoxetine, 18, 19 Cyp19 gene, 3 Fluvoxamine, 19 Cytochrome P450, 3–4 Forced swim test, 100 Fragile X syndrome (FXS) association with autism, 210–215, 218, D 222–225 D3, 194, 197, 198 diagnostic criteria, 215, 218 DA- and cyclic AMP-regulated phosphoprotein gender difference explanation, 222–223 (DARPP–32), 84, 85 gender differences, 215–216, 222 Dehydroepianstrosterone (DHEA), 3 gender signatures, 222 Depression, 98, 210 prevalence, 215–216 socialization, 210 Dihydrotestosterone (DHT), 8, 65 Dopamine (DA), 75, 83–88, 102, 191, 194, G 195, 197–204 Gamma-aminobutyric acid (GABA), 86–88 Dorso-lateral prefrontal cortex (DLPFC), 194 Gender, 231–243 Dorsoraphe nucleus (DRN), 201, 202 Gene-environment interactions, 210 D2 receptor, 131, 194, 197, 198, 203 Genotype-by-ethnicity interaction, 129 Drug abuse phases Glutamate, 112 acquisition, 74, 77, 79 Glutamate and oestrogen, 51–52 escalation, 74, 75, 77, 79, 87 Glutamic acid decarboxylase (GAD), 8 extinction, 74, 77, 81, 87 GnRH secretory system, 2 reinstatement, 74, 77, 78, 81, 87 Gonadal dysfunction, 164–165 GPR30, 7 E Environmental conditions, 65–66 H Epidemiological, 158–159 High-functioning autism, 215, 217, 218 Estradiol, 165–167 Hippocampus, 58–59, 101 17b-Estradiol (E2), 3, 161 Hormonal influences, 145–147 Estriol (E3), 3 Hormone replacement therapy (HRT), 162, Estrogen receptors 201, 202 ER-a, 75, 78, 82, 85, 86 regime, 8 ER-b, 75, 78, 82, 85–88 Hormones, 233, 235, 237, 239–243 Estrogens, 189–204 reproductive hormones, 233, 240–242 basic research findings, 157–158 5-HT1A receptor, 21, 101 clinical findings, 159–160 5-HT1B receptors, 23 epidemiological findings, 158–159 5-HT neurotransmission, 18 historical findings, 156–157 5-Hydroxytryptamine (5-HT) system, 17, intervention, 160–163 200–204 paradox, 189–204 Hypersexual behaviour, 26–27 Index 253 Hypoestrogenism, 163–164 Nucleus accumbens, 82, 84–86 Hypothalamic–pituitary–adrenal (HPA) axis, Nucleus basalis magnocellularis (NBM), 59 75, 87–88, 99, 191, 194–196, 198–204 Hypothalamic–pituitary–gonadal (HPG) axis, O 156, 167, 191, 196, 200 Object displacement (OD), 39 Hypothalamic–pituitary–ovarian axis, Oestradiol, brain, 176–177 176, 183 Oestrogen Hypothalamus, 101, 110 ERa, 4 ERb, 4 mechanism, 5 I SERMs, 6 Immune, 113 Oestrogen receptors (ERs), 38 Oestrous cycle, 104 OFC, 194 L Opioid, 196 Learned helplessness behaviour, 102 Oscillation, 197 Learning and memory, 99 Lipopolysaccharide (LPS), 109 Long-term potentiation (LTP), 58 P Lordosis quotient (LQ), 27 Panic disorder, 129 Paroxetine, 18, 19 Pathogenesis, 235, 240, 242 M Pervasive developmental disorders (PDD), 211 Males, 195–199, 201–203 diagnostic criteria, 215, 218 MB-COMT, 121 Pharmacokinetics, 232, 239–240 Menopause, 232, 233, 235, 238, 240–242 CYP, 239–240 Menstrual cycle, 75–76 Positive and negative symptoms scale Meta-analysis, 127 (PANSS), 179–180 Met158 homozygotes, 121, 127 Positron emission tomography (PET), 194, Midbrain central gray (MCG), 16 197, 201, 233, 234 Million Women Study (MWS), 6 Postmenopausal, 162 Mitogen-activated protein kinase (MAPK), Postpartum affective symptoms, 176 7, 61 PPI and PPF effects, 143 Monoamine level, 28 Prefrontal cortex, 110 Monoamines, 113, 233, 234, 237, 242 Premenstrual affective symptoms, 176 Morris water maze (MWM), 43 Preoptic area (POA), 16 Prepulse-elicited startle modulation (PESM), 142–143 N hormonal influences, 145–147 Neurochemical, 113 ovarian hormones, 147 Neurodevelopmental disorders, 210, 211, schizophrenia, 143–144 224, 225 sensorimotor gating, 142–143 prevalence, 210, 215, 221 sex differences and menstrual phase Neurogenesis, 100 effects, 144–145 Neuroplasticity, 113 Prepulse inhibition (PPI), 142, 177 Neurotransmission, 50–51 Progesterone, 2, 147 Neurotransmitters MAPK, ERK signal, 7 dopamine, 234, 235 PR-A, 7 norepinephrine, 234–237, 241 PR-B, 7 serotonin, 30, 233, 234, 237, 241, 242 synthetic progestogens, 8 Noradrenaline, 102 Progesterone (PROG), 75–80, 82, 86–88 Novel object recognition (NOR), 39 Protein kinase A (PKA), 83, 84 254 Index Protein kinase C (PKC), 178 Sex hormone-binding globulin (SHBG), 4 Psycho education, 225 Sex steroids, 63–64 Psychotic symptoms, 159 activational effect, 63, 64 Puberty, 191, 195–199 Alzheimer’s disease, 66–67 Punish/punishing/punishment, 190, Sexual dimorphisms, 122–123, 132 192–195, 197 Sexually dimorphic effects, 124 Putamen, 197 Sickness behaviour, 109 Single nucleotide polymorphisms (SNPs), 121, 144 R Spatial learning, 104 Radial arm maze (RAM), 43 Stimulus onset asynchrony (SOA), 142 Restraint stress, 105 Stress, 98, 99, 191, 192, 195–196, 198–199, Reward, 106, 190–200, 203, 204 201, 202, 204 Stress and addiction, 75–79, 81, 83, 84, 86, 87 Striatum, 110, 197 S Substance abuse, 209 SAM level, 131 Schizophrenia, 128, 142, 163–164, 174–175 oestradiol effects, 177–178 T treatment, 179–180 Testosterone imbalance, 2 Selective oestrogen receptor down-regulators Treatment, 191, 195, 198–204 (SERDs), 10 Selective serotonin reuptake inhibitors V (SSRI), 17, 199–204 Val158 homozygotes, 121, 127 Septo-hippocampal cholinergic neurons, 62–63 Ventral striatum, 192–194 Serotonergic receptors, 17 Ventral tegmental area, 82 Serotonin, 17–18, 111, 191, 195, 199–203 Ventromedial nucleus hypothalamus Serotonin transporter (SERT), 21 (VMH), 16 SERT-KO Rats, 29–30 Visual memory, 221, 222 Sertraline, 18, 19 Sex, 99, 189–203 by-genotype, 123 W differences, 99, 125–126 Women’s Health Initiative (WHI), 6 differences and menstrual phase effects, Working memory, 220–222 144–145 and hormonal influences, 147–148 hormones, 210, 223, 224 X testosterone, 223, 224 X chromosome, 210, 213, 216, 220, 222, 223 Sex hormone action X imprinting theory, 223 glutamate and oestrogen, 51–52 hippocampal architecture, 48–49 neurotransmission, 50–51 Z oestrogen receptors, 49–50 Ziggurat task (ZT), 43

A Primer of Neuroimmunological Disease Andrew R. Pachner A Primer of Neuroimmunological Disease Andrew R. Pachner Department of Neurology and Neuroscience New Jersey Medical School University of Medicine and Dentistry of New Jersey Newark, NJ, USA ISBN 978-1-4614-2187-0 e-ISBN 978-1-4614-2188-7 DOI 10.1007/978-1-4614-2188-7 Springer New York Dordrecht Heidelberg London Library of Congress Control Number: 2012930829 © Springer Science+Business Media, LLC 2012 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identifi ed as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface Neuroimmunologists deal with the nervous system and the immune system, both of which are giant, complex communication networks. One would think that we would be excellent communicators ourselves, but we have not com- municated well with individuals outside our fi eld. This is very unfortunate because the fi eld of neuroimmunology is more dependent than most on input from fi elds outside its own. Researchers in basic neuroscience, basic immu- nology, clinical neurology (to name just a few) have much to contribute and these contributions would be enhanced if those researchers had a better under- standing of neuroimmunology. This book is an attempt to provide a basic understanding of some of the neuroimmunological diseases to individuals who are not neuroimmunologists. Who should use this book? I have lofty ambitions for this book in that I think it can be helpful to a large number of people, such as basic scientists in both neuroscience and immunology, neurologists, and motivated individu- als in pharmaceutical companies who are neither PhDs nor MDs. Like Icarus, who had to navigate a path not too close to the sun nor too close to the sea, I tried to be basic enough to be understood by neophytes yet having enough depth so that it would not lose the attention of more-educated readers. Time will tell whether I succeeded. Why now? There are many reasons. One reason is that the most common neuroimmunological disease, multiple sclerosis, covered in fi ve chapters in this book, is attracting increasing interest from pharmaceutical companies as a therapeutic target. “Unmet need” is an understatement when it comes to improving our therapy of this prevalent disabling disease of the young. Another reason for the need now for this book is that there has been a para- digm shift in our understanding of the immune response within the nervous system. Far from being an “immune-privileged” tissue, haughtily excluding itself from any immune functions, the nervous system is actively involved in immune responses; it is simply that it participates using its own rules which are actively being researched but remain to be fully elucidated. A third reason for the need for this book is that increasingly, diseases thought to have a “degenerative” etiology, such as stroke or Alzheimer’s, have a component related to the immune system. This subdivision within neuroimmunology, dis- cussed briefl y in Chap. 15 , will likely grow substantially in the near future. How could I possibly cover neurology, immunology, neuroimmunology, and neuroimmunological disease in a short book? The short answer is that I can’t. v vi Preface However, this is a primer, not a complete textbook. It will help the reader most as an introduction, and as a guide to what areas to pursue in the literature. It is cus- tomary for an author to lament about how large his subject is, and how many corners needed to be cut, and I will certainly adhere to the custom. But I tried to make the fi eld of neuroimmunology understandable to a wide audience without being too lengthy. Have I been too cynical about the state of our knowledge and the effi cacy of available therapy? One of the physicians in the fi eld who reviewed some of the chapters thought so. He felt I was “riding roughshod” and being too “ curmudgeonly” and wished me to “explain the various drugs with great enthusiasm.” I apologize to him, and to those who wanted this book to be more upbeat. I did not intend to have any part of the book interpreted in a way that in any way is negative about the fi eld of neuroimmunology or those prac- ticing this subspecialty. I have been a neuroimmunologist for 30 years and love the fi eld and the people who work in it. However, I also adhere to the tenet, “primum non nocere” (the fi rst rule is to do no harm), and I feel that the benefi t/risk considerations should be clearly weighted toward benefi t prior to recommending a therapy. Unfortunately, the trend in the fi eld is to move in the other direction, toward therapies that are increasingly risky with question- able benefi t to show for it. It is possible that in a future of evidence-based medicine and increasing accountability, we will have better tools to measure benefi t/risk ratios in order to avoid major side effects and to maximize benefi t. What’s in the future for neuroimmunology? I see the partnership between basic neuroscience and neuroimmunology becoming stronger, and advances in our understanding leading to further major advances in diagnosis and ther- apy. We will benefi t from advances toward neuroprotective therapies in other parts of neuroscience to provide clues to ameliorate neurodegeneration in neuroimmunological diseases. Ultimately, our understanding of MS will increase and we will identify more and more effective therapies. From my mouth to God’s ears… I could not have written this book without a great deal of help. Steve Kamin, the chairman of our department of neurology at UMDNJ—New Jersey Medical School, was very supportive and allowed me to take sabbati- cal time. Susan Goelz, Lew Fredane, David Lagunoff, Norm Kachuk, Steve Kamin, and Stuart Selonick edited chapters, and aligned my frequently mud- dled efforts. The staff at Springer were extremely helpful, especially Andy Kwan and Richard Lansing. My daughter, Anna, helped considerably with image issues. And of course my long-suffering wife, Barbara, who had to put up with my periods of both mania and depression, was always there for emotional support. Newark, NJ, USA Andrew R. Pachner Acknowledgments Acknowledgments for Helpful Discussions and Providing Material Special thanks to Susan Goelz, Lew Fredane, Norm Kachuk, Steve Kamin, David Lagunoff, and Stuart Selonick who patiently read through the tortured prose of early versions and made much-needed recommendations. Jack Antel Klaus Bendtzen Joe Berger Bruce Cohen Nicolas Collongues Kathy Conant Gary Cutter Martin Daumer Peter Dyck Florian Eichler Patricia Fitzgerald-Bocarsley John Foley Doug Green Ken Gorson Wayne Hogrefe Doug Jeffrey Dimetrios Karussis Susumu Kusunoki Norman Latov Hans Lassman Vanda Lennon Howard Lipton Bob Lisak Michael Lockshin Christina Marra Jennifer Michaels Jana Preiningerova Harry Prince Kotil Rammohan John Richert David Richman vii viii Acknowledgments Moses Rodriguez Myrna Rosenfeld Walter Royal Subraminam Sriram Israel Steiner Carlo Tornatore Helen Tremlett Ken Tyler Angela Vincent Brian Weinshenker Hugh Willison Gil Wolfe Robert Yu Special thanks to my wife, Barbara, who patiently tolerated my idiosyncrasies, and to my daughter, Anna, who assisted me with getting images ready for the book. Thanks also to Richard Lansing, my editor, who made my fi rst experience as an author of a single-author text a pleasant one. Contents 1 Immunology for the Non-immunologist . 1 1 The Beginnings of Immunology . 1 2 The Components of the Healthy Immune Response . 2 2.1 White Blood Cells . 4 2.2 Molecules . 8 References . 13 2 Neurology for the Non-neurologist . 15 1 Organization of the Nervous System . 15 1.1 Electrical Nature: Nerve Transmission and Neurotransmitters . 15 1.2 Cells of the Nervous System . 16 1.3 Structure of the Nervous System: CNS, PNS, Upper and Lower Motor Neurons . 18 2 The Neurological Evaluation . 21 2.1 Neurological Examination . 21 2.2 Imaging of the Nervous System . 22 2.3 EEG and EMG . 23 References . 24 3 Neuroimmunology for the Non-neuroimmunologist . 25 1 The Beginnings of Neuroimmunology: Post-vaccinial Encephalomyelitis . 25 2 Semple Rabies Vaccine Autoimmune Encephalomyelitis: Temporal Progression. Interplay Between the Nervous and Immune Systems . 29 2.1 Stage 1. DAY 0: Exposure to the Antigen . 29 2.2 Stage 2. Days 0–7: Lymph Node Drainage and Processing of Antigen in Peripheral Lymph Node . 29 2.3 Stage 3. Days 7–10: Recruitment of Myelin-Specifi c Lymphocytes into the CNS . 30 2.4 Stage 4. Days 10–20: Maximal Infl ammation with Involvement of Local CNS Immunity, Including Cervical Lymph Nodes . 30 2.5 Stage 5. Days 20 and Later: Recovery . 31 ix x Contents 3 The Tools of the Neuroimmunologist . 31 4 Aspects of Infl ammation in Neuroimmunology Unique to the Nervous System . 32 5 The Necessity for Great Care in Classifying a Neuroimmunological Disease as “Autoimmune” . 33 6 The Importance of Antibodies . 34 References . 35 4 The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, a Precis . 37 1 Defi nition . 37 2 Etiopathogenesis . 37 3 Pathology . 38 4 Genetics and Epidemiology . 39 5 Clinical Manifestations . 39 5.1 Initial Symptoms . 39 5.2 The MS Attack . 40 6 Natural History and Prognosis . 42 7 MS Clinical Classifi cations . 43 7.1 “Form of MS” . 44 7.2 Disability . 45 7.3 Activity. 45 7.4 Severity . 46 References . 46 5 Multiple Sclerosis: Diagnosis . 49 1 History and Examination . 50 2 Laboratory Findings . 51 2.1 Routine Studies: Blood, Urine, Chest X-Ray . 51 2.2 CNS Imaging . 51 2.3 Cerebrospinal Fluid Analysis . 54 References . 55 6 Multiple Sclerosis Mimics . 57 1 Cerebrovascular Disease/Stroke. 58 2 Neurological Infections . 60 2.1 HIV . 60 2.2 Neurosyphilis . 60 2.3 Neurocysticercosis . 61 2.4 Lyme Disease . 61 2.5 Tropical Spastic Paraparesis . 61 2.6 Tuberculosis . 61 2.7 Brain Abscess . 62 3 NMO . 62 4 ADEM . 63 5 Leukodystrophies . 63 Contents xi 6 Other Conditions . 63 6.1 Neurosarcoidosis . 63 6.2 Subacute Combined Degeneration . 65 6.3 Other Neuroinfl ammatory Diseases . 65 References . 66 7 Multiple Sclerosis Therapy . 69 1 Disease-Modifying Drugs . 69 1.1 How Medications Become Approved for Use in MS . 69 1.2 The Primary Endpoint . 70 1.3 When Should One Treat with DMDs? . 71 1.4 General Approach to Therapy . 71 1.5 Current Agents . 72 2 Symptomatic Therapies . 78 References . 80 8 Experimental Models of MS . 83 1 Animal Models of MS . 83 1.1 Autoimmune . 83 1.2 Viral . 87 1.3 Demyelination Induced by Toxins . 89 2 In Vitro Models of MS . 89 3 Animal Models of Neuromyelitis Optica (NMO) and the Use of Passive Transfer Models . 89 References . 90 9 Guillain–Barré Syndrome (GBS) and Other Immune-Mediated Neuropathies . 93 1 Defi nition . 93 2 Etiopathogenesis . 93 3 Pathology . 95 4 Epidemiology and Etiopathogenesis . 95 5 Clinical Manifestations . 96 6 Natural History and Prognosis . 96 7 Classifi cation . 96 8 Diagnosis . 97 9 Therapy . 97 10 GBS’s Cousin: Chronic Infl ammatory Demyelinating Polyneuropathy . 98 11 Neuropathy Associated with Monoclonal Gammopathy . 98 12 Experimental Neuritis . 100 References . 101 10 Neuromuscular Neuroimmunological Diseases: Myasthenia Gravis . 103 1 Defi nition . 103 2 Etiopathogenesis . 103 3 Pathology . 104 4 Genetics and Epidemiology .

105 xii Contents 5 Clinical Manifestations . 105 6 Natural History and Prognosis . 106 7 Classifi cation . 106 8 Diagnosis . 106 9 Therapy . 108 10 Lambert–Eaton Myasthenic Syndrome . 108 11 Neonatal MG and Arthrogryposis Multiplex Congenita . 109 12 Experimental Models of MG . 109 References . 110 11 The Prototypic Neuroimmunological Muscle Disease: Dermatomyositis . 111 1 Defi nition . 111 2 Etiopathogenesis . 111 3 Pathology . 111 4 Genetics and Epidemiology . 112 5 Clinical Manifestations . 112 6 Natural History and Prognosis . 112 7 Classifi cation . 112 8 Diagnosis . 112 9 Therapy . 113 10 Related Neuroimmunological Muscle Diseases . 113 11 Experimental Models of Infl ammatory Muscle Disease . 114 References . 114 12 A Introduction to Neurological Infections: Neuro-infectious Disease as Part of Neuroimmunology . 115 1 General Rules of Neuro-infectious Diseases . 116 1.1 Infection of the Nervous System Follows Systemic Infection . 116 1.2 Neuro-infectious Diseases Should Be in the Differential Diagnosis in Many Patients with Diffi cult Neurological Syndromes Because of Their Reversibility with Antibiotics . 116 1.3 Diagnosis by Identifi cation of the Infectious Agent Is Ideal, but Sometimes Impossible. 116 1.4 Prompt Recognition of Curable Infectious Diseases Is Critical . 117 1.5 Therapy of Neuro-infectious Diseases Is Frequently More Diffi cult than Therapy of Infections Elsewhere in the Body . 119 1.6 Always Keep HIV/AIDS in Mind . 119 2 Lyme Meningitis: The Prototypic Meningitis . 119 2.1 Defi nition . 119 2.2 Etiopathogenesis . 119 2.3 Clinical Manifestations . 121 2.4 Natural History/Prognosis . 122 Contents xiii 2.5 Diagnosis. . 122 2.6 Therapy . 123 2.7 Classifi cation . 123 2.8 Selected Important Infectious Meningitides . 123 3 Herpes Simplex Encephalitis: The Prototypic CNS Parenchymal Infection . 125 3.1 Defi nition . 125 3.2 Etiopathogenesis/Pathology/Genetics/ Epidemiology . 125 3.3 Clinical Manifestations . 126 3.4 Natural History and Prognosis . 127 3.5 Diagnosis. . 127 3.6 Therapy . 128 3.7 Other Important CNS Parenchymal Infections . 128 3.8 Rabies, Poliomyelitis, and the Wonder of Vaccination . 132 4 Infectious Neuritis: Neuropathies of Leprosy and Varicella Zoster Virus . 133 4.1 Leprosy . 134 4.2 VZV Infection . 136 4.3 Immunosuppressed Patients . 136 References . 139 13 Neurological Manifestations of Systemic Chronic Infl ammatory Disease . 141 1 Neurosarcoidosis . 141 2 Systemic Lupus Erythematosus . 141 3 Antiphospholipid Antibody Syndrome . 142 4 Sjogren’s Syndrome . 143 5 Vasculitis . 144 References . 146 14 The Neuroimmunology of Cancer: Paraneoplastic Syndromes and Primary CNS Lymphoma . 147 1 Paraneoplastic Neurological Disorders . 147 1.1 Defi nition . 147 1.2 Etiopathogenesis . 147 1.3 Pathology . 148 1.4 Genetics and Epidemiology . 148 1.5 Clinical Manifestations . 148 1.6 Natural History and Prognosis of PND . 151 1.7 Classifi cation . 151 1.8 Diagnosis . 152 1.9 Therapy . 152 2 CNS Lymphoma. 152 References . 153 xiv Contents 15 Neuroimmunology of Degenerative Diseases and Stroke . 155 1 Introduction . 155 2 Neuroimmunology of Alzheimer’s Disease . 155 3 Neuroimmunology of Parkinson’s Disease . 156 4 Neuroimmunology of Stroke . 157 References . 158 16 Important Rare Neuroimmunological Diseases . 159 1 Infectious/Postinfectious . 159 1.1 Subacute Sclerosing Panencephalitis . 159 1.2 Whipple’s . 160 1.3 Post-Varicella Zoster Virus Cerebellar Syndrome . 161 1.4 Sydenham’s Chorea . 161 2 Autoimmune . 162 2.1 Acquired Neuromyotonia . 162 2.2 Stiff Person Syndrome . 162 2.3 Swine-Worker’s Neuropathy . 163 3 Idiopathic . 163 3.1 Hashimoto’s Encephalopathy . 163 3.2 Behcet’s Syndrome . 164 3.3 Rasmussen’s Encephalitis . 164 3.4 Acute Multifocal Placoid Pigment Epitheliopathy . 164 References . 164 17 Neuroimmunological Molecules and Translational Medicine . 167 1 Moving from Basic Science Discoveries to FDA-Approved Therapies . 167 2 Biological Molecules as Therapies . 167 2.1 Therapeutic Monoclonal Antibodies . 167 2.2 Molecules as Targets of Therapy or of Disease: CD20, Aquaporin-4 Receptor, TNF-a, Sphingosine- 1-Phosphate Receptors, CD52, MOG, Channels . 169 2.3 Neuroprotection: The Holy Grail of Translational Neurology . 172 References . 173 18 Neuroimmunological Diagnostic Tests . 175 1 General Considerations for Testing . 175 1.1 Validation of Laboratory Tests by Regulatory Authorities . 176 2 Blood Tests . 176 2.1 Blood Tests for Infl ammation . 176 2.2 Blood Tests for Specifi c Immunity to Pathogens or Autoantibodies . 177 2.3 Blood Tests for Detecting Specifi c Pathogens . 182 Contents xv 3 Cerebrospinal Fluid (CSF) . 183 3.1 Antibodies in the CSF . 185 3.2 Detection of Pathogens in the CSF . 186 4 Tests of Immune Function . 187 4.1 Humoral Immunity . 187 4.2 Cellular Immunity . 188 References . 188 19 Therapy in Neuroimmunological Disease . 189 1 Introduction . 189 2 Chemicals . 190 2.1 Corticosteroids . 190 2.2 Immunosuppressives . 192 3 Biologics: Large Molecules Produced via Recombinant Technology or from Human Specimens . 196 3.1 Intravenous Immunoglobulin . 196 3.2 Cytokines . 196 3.3 Monoclonal Antibodies (See Sect. 2.1 in Chap. 17) . 197 4 Procedures . 197 4.1 Plasmapheresis . 197 4.2 Thymectomy . 198 References . 198 Index . 199 Immunology for the Non-immunologist 1 1 The Beginnings of Immunology Inset 1.1 The Case of Smallpox and the Power of Immunology The focus of immunology, both historically and conceptually, is the defensive response of a verte- At-risk population . All ages in all countries brate animal (i.e., humans or animal models) to prior to 1950. Hundreds of thousands of microorganisms leading to clearance of the Europeans died each year from the infection. pathogen, maintenance of homeostasis, and Cause . Infection with the smallpox (variola enhanced protection in the future to the same or virus), a very large virus of the poxvirus group, similar microorganisms. Prior to the second half consisting of a genome of almost 200,000 bp of the twentieth century, infectious diseases, of double-stranded DNA packaged into a especially those encountered during childhood, virion measuring about 200 × 300 nm. were massive public health threats. Although vaccines and antibiotics have blunted the threat, Symptoms and signs . After an incubation infections remain major causes of morbidity and period of about a week and a half, fever, mortality, and the immune response to estab- malaise, and a rash appear. The rash goes lished infections, as well as new/emerging infec- through a predictable cycle of papules, ves- tions, remains the nexus of immunology. An icles, and pustules, which ultimately crust example of the importance of infections in immu- (see Fig. 1 .1 ). Transmission is via the respi- nology is that in many medical schools, microbi- ratory tract followed by periods of viremia ology and immunology are within the same resulting in spread to the rest of the body. department. Morbidity/mortality . Mortality of the acute The father of immunology is generally felt to infection was generally around 30% of be Edward Jenner, who, at the end of the eigh- those infected, although with children, the teenth century began using cowpox vaccination number was higher. Individuals recovering in England to protect against smallpox (see Inset from smallpox usually experienced no 1.1 and Fig. 1 .1 ). However, he was not the fi rst sequelae except for pockmarks on the face person to utilize immunology to protect against which could be disfi guring. infection. The practice of “variolation,” purpose- Treatment . None. ful inoculation with smallpox (Variola) in a con- trolled manner to limit the effects of natural Prevention . Vaccination. Intensive global vac- infection, had been around for many decades and cination efforts led to the global eradication possibly for centuries prior to Jenner. Smallpox of smallpox so that by 1980, smallpox was had been a major public health problem in civili- declared as being eradicated from the world. zation for many centuries. A.R. Pachner, A Primer of Neuroimmunological Disease, 1 DOI 10.1007/978-1-4614-2188-7_1, © Springer Science+Business Media, LLC 2012 2 1 Immunology for the Non-immunologist disease, (see Chap. 15 ), have been found to have substantial immunological contributions. 2 The Components of the Healthy Immune Response Given the fact that the historical foundations of immunology were laid in man’s response to infection, and infectious diseases are a battle between the pathogen and the host’s immune sys- tem, it is not surprising that much of the language of immunology is the language of war. There is “enemy,” “invasion,” “targeting,” “killing,” “defense,” “decoy,” etc. A human’s immune sys- tem must be extremely powerful to overwhelm the large variety of enemies invading the body, and ultimately the power of the immune system must be greater than the power of the invader, or the invader will kill the human. Just as a prosper- Fig. 1.1 A child with smallpox. This girl from Bangladesh developed smallpox in 1973. Freedom from smallpox was ous, civilized society such as the USA, or a highly declared in Bangladesh in December, 1977 when a WHO functional animal such as the human, must have International Commission offi cially certifi ed that small- the power of a strong military/immune response, pox had been eradicated from that country. From CDC both must also have a very complex, sophisti- image fi les available in the public domain at h ttp:// commons.wikimedia.org/wiki/File:Child_with_ cated regulatory mechanism, so that the power is Smallpox_Bangladesh.jpg ) not brought against the state/human itself. Both the human and the state suffer terrible con- sequences if the immune/military arm is inade- However, as the fi eld of immunology has quately or excessively controlled, and both matured, it has begun to be applied to many more constantly adjust the regulatory mechanisms to fi elds outside of microbiology and infectious dis- achieve optimal balance. Unfortunately, our eases. For instance, an increasing number of dis- understanding of both the weapons and control of eases are being recognized as being “autoimmune” the immune system are primitive, and our in which the normal barriers to immune reactions attempts at manipulating the immune response in against self-components are breached. Also there disease are thus necessarily crude, as will be dis- are diseases that are mistakenly characterized as cussed in Chap. 19 . being “autoimmune”; the defi nition of autoim- Two helpful classifi cations of the immune munity within neuroimmunology will be dis- response are those of c ells/molecules involved, cussed in Chap. 3 . Another area of intense interest summarized in Table 1 .1 , and their participation within immunology has been the immune in the i nnate vs. adaptive immune response. response to cancers, since immunosuppression The innate immune response occurs early after either via medications or via infections such as infection begins. Thus, in the example of Lyme the human immunodefi ciency virus (HIV) results disease, an infection that is clinically important in increased incidence of malignancies. And even in many parts of the USA and Europe, the innate more recently, within the past decade, neurologi- immune response occurs within the fi rst few cal diseases, thought previously to be “degenera- days after the tick bite which injects the causative tive,” such as stroke, Parkinson’s, and Alzheimer’s bacterium, B orrelia burgdorferi , into the skin. 2 The Components of the Healthy Immune Response 3 Table 1.1 Major cells/molecules involved in the healthy immune response Cell/molecule Subclassifi cation White blood cell Lymphocytes, polymorphonuclear leukocytes, macrophages, and monocytes, dendritic cells Immunoglobulin Isotypes Major histocompatibility complex (MHC) I and II Cytokine Cell derivation, TNF superfamily, chemokines, interferons Cluster of differentiation (CD) antigens Surface proteins used to identify functionally distinct immune cells Polymorphonuclear leukocytes and macrophages of relevant cells and death and clearance of are quickly recruited to the site of infection unneeded lymphocytes is an important part of the leading to redness, swelling, and local pain. immune response. Natural antibodies, which are present without Apoptosis, also called programmed cell death previous exposure to the pathogen, bind to the (PCD), which has only attracted interest in the bacteria and activate complement. Cytokines, last few decades, is a critical process in a highly important communication and effector mole- regulated system such as the immune response. cules of the immune response (see below), accu- It is induced by both intracellular and extra- mulate locally and enhance the infl ammation. cellular signals, which can be either pro- or anti- Products of degradation of the bacteria activate apoptotic. The fi nal effectors are proteolytic a variety of cells through Toll-like

receptors cysteine-dependent aspartate-directed proteases (TLRs). All of these processes utilize weapons (caspases). Important apoptotic molecules against the bacteria that are already present and involved in the fi nal regulation of caspases are ready, and none require the production of novel the cytokine tumor necrosis factor (TNF) and its molecules, or the generation of new classes of receptors, Fas receptor (also called CD95) and cells. Fas ligand, members of the Bcl-2 family. In contrast, by 5–7 days after infection, many If the infection persists, the weapons of the of these processes are waning, and the a daptive adaptive response become more and more power- immune response is taking over. The adaptive ful, and in the vast majority of infected individu- immune response, led by B cells and T cells with als the power of the immune response is adequate receptors specifi c for Borrelia burgdorferi pro- to kill all the spirochetes and the infection is teins, is necessarily later than the innate response, cleared. Only a small percentage of unfortunate since it utilizes molecules and cells specifi cally infected humans become persistently infected “adapted” for the invading organism, which are with the spirochete, and are at risk for developing byproducts of relatively complex and thus slower some of the more serious late complications such processes, such as genetic recombination and as neurological complications or arthritis. In hypermutation occurring in lymphoid tissue. Lyme disease as in most infections, the factors These cells, once “produced” and replicating, that determine why a relatively small percentage traffi c to the sites of infection and local lymphoid of infected individuals cannot clear the infection tissue, utilizing adhesion molecules to guide are unknown and likely relate to both host and them, and continue to proliferate. Lymphocytes pathogen factors. which do not have specifi city for the pathogen’s Key components of the adaptive immune antigens also traffi c to sites of infection, but do receptor are a family of receptors on the surface not proliferate, and instead, without stimuli to of B- and T cells, called antigen receptors, which proliferate, die in an orderly regulated process of bind with high affi nity to the newly identifi ed death called apoptosis. The selective expansion antigens. The B-cell receptor (BCR) consists of 4 1 Immunology for the Non-immunologist the Fab of the immunoglobulin molecule produced lymphocytes in the past 50 years, far more than any by the B cell (see discussion of immunoglobulin other of the immune cell types. Lymphocytes can structure below) and can bind the antigen directly be either small, 7–10 m m in diameter, such as the without the need for another cell type. Activation thymus-derived cell (T cell) or the bursa-derived of the T-cell receptor (TCR) requires an antigen- cell (B cell), or large, 10–13 m m in diameter, such presenting cell (APC) which “processes” an anti- as natural killer cell (NK cell). There are approxi- gen partly by chopping it into small pieces, and mately 500 billion, i.e., 5 × 101 1 , lymphocytes pres- then presenting it to the T cell after it has bound ent in the human body at any one time, almost all of to the major histocompatibility complex (MHC) them in the lymphoid tissues. Lymphocyte kinetics complex. This combination of the APC and its are quite complex for two reasons. First, lympho- MHC complex, the antigen piece, and the TCR is cytes are travelers, traffi cking constantly through sometimes called the “trimolecular complex” of lymphoid tissues and blood. Secondly, they fre- T-cell activation. quently die soon after coming to maturity only to Once the bacteria have been cleared, the be replaced by newly produced lymphocytes. The immune system of the individual infected with movement of lymphocytes in response to a stimu- Borrelia burgdorferi does not “forget” the infec- lus to the immune system, including a brief descrip- tion, but utilizes one of the key aspects of the tion of lymph nodes, lymph vessels, and traffi cking adaptive immune response, i.e., immunological to the nervous system, is in Chap. 3 . memory. Memory B cells, memory T cells, and immunoglobulins which bind with high affi nity B Cell to the spirochete all continue to be present for The “B” in B cell comes from the name “bursa of years after infection, possibly for the lifetime of Fabricius,” a specialized organ in birds; this sub- the individual, and protect from future infection. population was fi rst described in the 1960s as These powerful weapons are dormant but can “bursa-derived” in birds. Later research deter- leap to action should any infection resembling mined that mammalian B cells develop in the Lyme disease return. bone marrow and spleen. B cells have many func- tions, but most immunologists would consider their primary role to be to develop into immuno- 2.1 White Blood Cells globulin-producing cells, called plasma cells, responsible for the immunoglobulins, also called Centrifugation of blood separates cells in the blood antibodies, which circulate and are involved in into two cellular compartments, the red compart- many effector and protective functions of the ment comprising red blood cells, and the white immune system. Most B cells, however, never compartment, consisting of the less numerous, but develop into plasma cells, and B cells which pre- much larger and more complex, white blood cells. cede plasma cells in development can function by White blood cells are initially produced from pro- producing cytokines and by interacting with genitor cells in the primary lymphoid organs, the other immune cells. How important these multi- bone marrow and thymus, circulate throughout the ple roles are in most immune responses is not body, mostly into peripheral lymphoid organs such well understood. For example, the role of B cells as the lymph nodes, mucosa-associated lymphoid in the infl ammatory activity of multiple sclerosis tissue (MALT), and the spleen. Some white blood was unanticipated, until the strong anti-infl am- cells, such as plasma cells, terminally differenti- matory effects of B-cell-depleting therapy were ated B-lymphocytes which produce antibodies, identifi ed in a clinical trial treating MS with the circulate back into the bone marrow. anti-CD20 monoclonal antibody rituximab (see Chaps. 17 and 19 ). However, for survival pur- 2.1.1 Lymphocytes poses, the primary role of B cells in humans is Lymphocytes are the most well-studied of the white the production of antibody since children born blood cells. The National Library of Medicine without functional B cells, such as in X-linked data base records 480,000 scientifi c articles on agammaglobulinemia (XLA) (see Inset 1 .2 ) die 2 The Components of the Healthy Immune Response 5 of infections unless treated with intravenous Mature B cells are unique among other cells immunoglobulins; many children so treated will by surface expression of the BCR, which resembles live nearly normal life spans because of the strong an antibody molecule inserted into the membrane protective effects which immunoglobulins exert with the antigen-binding portion of the molecule against infection. on the outside. The antigen-binding portion, con- sisting of IgD or IgM antibodies, is bound to the surface. After binding and during cell activation, the BCRs cluster together. The characteristics of Inset 1.2 X-Linked Agammaglobulinemia; the BCR and its cousin, the TCR, are summarized Why We Need B Cells in Table 1.2. Most, but not all, B cells also have At-risk population . All children, but since it the surface expression of CD19 and CD20. is X-linked, it is much more common in B cells can be further divided into B-1 and B-2 males. Occurs in 1/100,000 male births. cells. B-1 cells are present in the fetus, and self- renew outside of lymphoid organs, while B-2 cells Cause . The disease is also called Bruton’s are produced after birth in the bone marrow and agammaglobulinemia because it was origi- spleen. B-1 cells, most of which express the nally described by Ogden Bruton. The marker CD5, are responsible for the production of genetic defi ciency is due to mutation in an IgM and IgG3 natural antibodies which are spe- enzyme, called Bruton’s tyrosine kinase cifi c for more than one antigen, and which have (Btk), causing a delay or block in B-cell low affi nities of binding. B-2 cells, in contrast, development and absent or severely produce IgM and IgG with relatively high affi nity reduced immunoglobulin levels. which require more extensive rearrangement of Symptoms and signs . After normal birth immunoglobulin molecules called somatic hyper- and early development, infants develop mutation. B-1 cells can be purifi ed from perito- frequent infections, which can be fatal if neal cavity lavages, while B-2 cells can be isolated the abnormality is not detected and treated. from peripheral blood, bone marrow, or spleen. Although bacterial infections are most common, some viral infections, particu- T Cell larly Enterovirus and Echovirus infections, T cells are defi ned as small lymphocytes, which can be particularly severe. bear surface TCR complexes, and do not have immunoglobulin on their surface. T cells are the Morbidity/mortality . As above. Treatment most common lymphocyte type in peripheral is life saving. blood and have many roles including direct kill- Treatment . Replacement of absent immu- ing of cells infected with viruses, enhancing anti- noglobulin with intravenously delivered body production by B cells, secretion of cytokines, human immunoglobulin (IVIg) from a pool and regulation of immune function. The “T” in of human donors. T cell comes from the thymus, the organ located beneath the sternum where T cells mature. Table 1.2 Characteristics of antigen-specifi c receptors Presence of Can bind antigen without antigen-specifi c involvement of other Requires presence of Minimum requirements Cell receptors cell type “antigen-presenting cell” for protein antigen B cell Yes Yes No Conformational structure T cell Yes No Yes Peptides Other white No No antigen-binding No antigen-binding No antigen-binding cells receptors receptors receptors 6 1 Immunology for the Non-immunologist Early in life, the thymus is responsible for gener- ating large numbers of T cells many of which die Inset 1.3 (continued) from positive or negative selection. Through adulthood, the thymus atrophies at a steady rate, The mean duration of this phase in an and new T cells are generated from expansion of untreated individual is about 10 years. The already existing T cells. The surface marker CD3, fi nal stage is that of AIDS, the development a critical part of the TCR, is often used to identify of opportunistic infections (OIs). Both CD4+ T cells. T cells were fi rst described in the 1960s T-cell counts and viral load in the blood are by Jacques Miller and others who revised earlier used as important biomarkers in the disease. conceptions of the thymus as a vestigial organ. Morbidity/mortality . Death in untreated Since their discovery, T cells have been the most individuals usually occurs within a year after studied of the lymphocytes accounting for nearly the development of AIDS, the fi nal stage. 300,000 scientifi c articles listed in the National Library of Medicine data base. T cells are critical Treatment . Highly active antiretroviral for survival; HIV infection kills infected humans therapy (HAART). A cocktail of a variety by depletion of T cells (see Inset 1 .3 ). of anti-viral drugs which keeps the viral load low and leads to prolonged remission. Prevention . Avoidance of exposure to the virus is the only way at this time to prevent HIV infection. At this time no vaccine has Inset 1.3 HIV/AIDS and Opportunistic demonstrated major effi cacy. Infections from T-Cell Defi ciency At-risk population . Adults in all countries, but particularly those practicing high-risk activities, such as intravenous drug abuse T cells are commonly divided into “helper” T and promiscuous sexual intercourse. Can (T ) cells which have CD4 on their surface and h be transmitted to infants by infected “help” B cells make antibody, “cytotoxic” T (T ) c mothers. cells, which have CD8 on their surface and kill virally infected cells, and “regulatory” T cells Cause . Infection with the HIV, which is a which do not have a clear-cut CD signature. T lentivirus, a member of the retrovirus fam- h cells can be further differentiated by the types of ily, of about 10,000 bases, and transmitted cytokines they produce: Th1 produces mostly as a single-stranded, positive-sense, envel- macrophage-activating cytokines such as IFN -g oped RNA virus. Disease and death in AIDS, and TNF- b ; Th2 produces

primarily B-cell- the fi nal stage of HIV infection, are gener- activating cytokines such as IL-4, IL-5, and ally due to opportunistic infections caused IL-10; and Th17 cells produce IL-17 and IL-6. by HIV-induced depletion of CD4+ T cells; Although regulatory T cells are considered by dysfunction of NK cells is also thought to some to be relative newcomers in immunological be important in susceptibility to OIs. research, they were actually described in the Symptoms and signs . There are four stages 1970s by Richard Gershon [1 ] (Fig . 1.2 ), an to the infection. The fi rst is an incubation immunologist at Yale, and were termed “suppres- period of approximately a month after initial sor” T cells [2 ]. “Suppressor” T cells, now called infection. The second is an “acute infection” T cells, or T cells, have strong effects on regulatory reg period also of about a month of a nonspe- immune processes, but their molecular and phe- cifi c viral syndrome of fever, malaise, swol- notypic characterization is extremely diffi cult, len lymph nodes, and muscle aches. The and they remain cells of mystery [3 , 4 ] . The fate third is a latent, asymptomatic phase. of many T cells is to circulate and die relatively quickly, but others become “memory” T cells and 2 The Components of the Healthy Immune Response 7 Fig. 1.2 R ichard K. Gershon, an immunologist at Yale Fig. 1.3 Pneumocystis jirovecii detected by methenamine who was ahead of his time when he fi rst described regula- silver stain from the sputum of an HIV patient with tory T cells, which he called suppressor T cells, in the early Pneumocystis pneumonia 1970s. This image is used with permission of Douglas Green, Ph.D. leukoencephalopathy (PML) caused by infection can remain viable for many years without known in the brain with the JC virus, a polyomavirus. activation; these T cells, as well as their memory T- and B cells which appear in the blood or ulti- B-cell cousins, are the basis for immunological mately in areas of infl ammation within the nervous memory, in which exposure to a previously system in neuroimmunological disease represent encountered antigen results in a highly acceler- the survivors of a process of the normal extensive ated response relative to the fi rst exposure. loss of lymphocytes through apoptosis, or PCD; N ot surprisingly for an entity as powerful as the these surviving lymphocytes meet complex “qual- immune system, tight regulation is required. T regs ity control” criteria. This selection process occurs are only one of a number of tools the immune sys- in secondary lymphoid tissue such as the lymph tem uses in self-regulation. Another well-studied nodes and spleen. Survivors of this process can be down-regulatory mechanism is tolerance, in which considered as having been “rescued” from aptop- cells that normally should be able to respond to an tosis, and once these lymphocytes become mature, antigen are unable to, due to a poorly understood most of them ultimately die unless they are acti- state of paralysis of the cell. Thus, the normal indi- vated. Activation occurs via interaction with their vidual has circulating immune cells which are antigen and appropriate other signals; part of the reactive to various self-antigens, but these are activation also involves proliferation of the lym- tolerized and do not respond pathologically. Some phocyte resulting in considerable expansion of the investigators feel that it is loss of self-tolerance clonal population. Proliferation of lymphocytes ex that is the cause of many autoimmune diseases. vivo can also be stimulated by mitogens, proteins Individuals with T-cell defi ciencies (see Inset which nonspecifi cally activate lymphocytes (see 1 .3 ) develop opportunistic infections (OIs), such discussion of lectins in Chap. 18 ). The progeny of as Pneumocystic pneumonias (Fig. 1 .3 ), and have these activated lymphocytes include “memory” an increased risk of malignancies, such as cells, which can last for years, and are the basis of Epstein–Barr virus-associated lymphoma and immunological memory. human herpes virus 8-associated Kaposi’s sar- coma. The most common OIs in AIDS patients 2.1.2 Polymorphonuclear Leukocytes are those with pneumocystis (a fungus), Candida (Neutrophils) (a fungus), tuberculosis (a bacterium), and cyto- Neutrophils, which constitute about half of the megalovirus. In patients with HIV/AIDS and total circulating white blood cells, can leave the neurological symptoms, other important OIs are circulation very quickly after the beginning of an CNS toxoplasmosis and progressive multifocal infection and enter tissues, and represent one 8 1 Immunology for the Non-immunologist of the earliest weapons in the innate immune without the need for prior stimulation. Some NK response. Neutrophils phagocytose bacteria and cells express CD56 at high levels. These CD56h i other pathogens which have been coated with cells may have immunoregulatory functions and antibodies and complement, and use their gran- are thought to be important in the mechanism of ules, which contain a variety of compounds, to action of daclizumab, a drug in phase 3 studies of kill pathogens. multiple sclerosis. Interestingly, CD56 is neural cell adhesion molecule (NCAM), which is also 2.1.3 Monocytes and Macrophages expressed on the neuronal and glial surface, and Monocytes circulate in the bloodstream for about is thought to be important in CNS function. 1–3 days after which they migrate into tissues Another important cell type related to mac- where they become tissue macrophages. They rophages and derived from monocytes are den- phagocytose, i.e., ingest, foreign substances such dritic cells (DCs). DCs are rarer than macrophages, as bacteria. This can be done directly by the rec- but are critical links between the innate and adap- ognition of certain nonhuman molecular patterns tive immune response. Immature DCs sample on microbes by the macrophages. The microbial their environment through the extension outward structures recognized by the innate immune system of multiple “dendrites” and become mature when are sometimes referred to as pathogen-associated they are activated by an antigen, at which point molecular patterns (PAMPs) and the receptors for they migrate to a local lymph node. There they them present on macrophages are called pattern activate antigen-specifi c T cells, part of the adap- recognition receptors (PRRs). Bacterial lipopoly- tive immune response. Mature DCs are consid- saccharides and fl agellar proteins contain PAMPs ered the best cells for antigen presentation to T which bind to specialized receptors on mac- cells since they can activate naive as well as rophages and dendritic cells called TLRs, a com- memory T cells, while B cells and macrophages, mon class of PRRs. Macrophages also have which can also present antigen to T cells, can receptors for the Fc portion of antibody and thus activate only memory T cells. There are two main can be activated to kill microbes which are coated types of human DCs: myeloid dendritic cells by antibody and complement, a process called (mDCs), which secrete IL-12, and plasmacytoid antibody-dependent cellular cytotoxicity dendritic cells (pDCs), which secrete type I inter- (ADCC). ferons, mostly interferon-a . The term “dendritic An important molecule that is upregulated in cell” has also confusingly been given to an macrophages during an immune response is nitric unrelated “follicular dendritic cell” (Fig. 1.4 ), oxide (NO), a gas produced by the enzyme induc- a macrophage-like residential cell of lymphoid ible nitric oxide synthetase (iNOS). NO is felt to be tissue, which is of mesenchymal, not hematopoi- an important mediator in both immune and non- etic, origin, and does not express MHC class II immune functions, but its precise role is unclear. antigens, and also has prominent dendrites. A nother cell type of the innate immune response that participates in ADCC via their sur- face expression of Fc receptors, and resembles 2.2 Molecules macrophages in some ways, are NK cells, natural killer cells, which are large and granular; NK 2.2.1 Immunoglobulin cells are considered key parts of the innate Immunoglobulins (Igs) are products of plasma immune response. NK cells are of lymphocyte, cells, which are terminally differentiated B cells. not monocyte lineage; they are derived from the They are very large molecules (Fig. 1.5 ), ranging same lymphoid precursors as those which give from 150 kDa for IgG to 970 kDa for IgM; in con- rise to B- and T-lymphocytes. They are negative trast, cytokines such as chemokines or interferons for the expression of CD3, the canonical T-cell (described below) are 12–20 kDa. The prototypic marker, and produce IL-10 and other cytokines effector molecules of the adaptive immune 2 The Components of the Healthy Immune Response 9 Fig. 1.4 Scanning electron microscopy (SEM) of a follicular dendritic cell showing dendritic regeneration Fig. 1.5 Immunoglobulin molecular structure. The immunoglobulin molecule is composed of two heavy chains and two light chains. Light chains exist in two classes: kappa and lambda. Either type may associate with any type of heavy chain isotype response are immunoglobulins of the IgG isotype, adaptive antibody response. The differences in the molecules with high affi nity for their epitopes amino acid sequence of the immunoglobulins which begin to appear in the second week of an produced by one plasma cell relative to those pro- immune response against a pathogen. Each single duced by other plasma cells can be divided into clone of plasma cells, produces many copies of an differences in the Fab or Fc portion; “ab” is an immunoglobulin unique for that plasma cell, and abbreviation for “antigen binding” and “c” is an many plasma cell clones contribute to an effective abbreviation for “constant.” The differences within 10 1 Immunology for the Non-immunologist the Fab portions of immunoglobulin molecules, 2.2.2 The Major Histocompatibility clustered in the fi rst 110 amino acids of the amino Complex terminal ends of the heavy and light chains (col- This is an exceptionally polymorphic gene com- ored red in the diagram), is dramatic since there plex on chromosome 6 in humans which con- are “hypervariable” areas within Fab that deter- tains over 200 genes; most other mammals have mine the ability of these molecules to bind anti- similar numbers of genes in their MHC, while genic epitopes. The variable region of the Fab chickens only have 19 genes. Its survival value represents the end product of a molecular restruc- likely derives from its ability to effi ciently pres- turing tour de force, a product of a combination of ent peptides from pathogens processed by APCs germ line sequences, recombination, somatic to the appropriate T-cell populations; in addi- hypermutation, gene conversion, and clonal dele- tion, a number of other cell types other than T tion which leads to a very impressive product, cells are also dependent upon the MHC for their whose affi nity of Fab for antigen can be as high as function and development. The largest classes 10− 12 M, i.e., nearly irreversible binding. Thus, due of MHC genes are class I and II, distinguished to all of this modifi cation, the fi nal 110 amino acid by the types of peptides which they are able to sequence of the molecule bears little relation to the present. In humans, MHC class I genes are encoded Fab sequence in the germ line. The Fc divided into HLA-A, -B, and -C, while class II portion is much less variable as identifi ed in its genes are HLA-DR, -DP, and -DQ. The most name, i.e., the “constant” region, which has no polymorphic of these genes is the beta subunit role in antigen binding but determines the interac- of the HLA-DR molecules which has over 500 tion of immunoglobulins with macrophages and different alleles. complement. There are fi ve major classes or iso- The recognition of antigens by antigen-specifi c types determined by the structure of the Fc portion T cells requires self-MHC. If the same antigen is of the heavy chain: IgG, IgA, IgM, IgD, and IgE, presented to an individual by cells which either in order of concentration in the serum. IgG is by do not bear MHC or bear MHC different than that far the most abundant and has four subclasses. of the individual, no activation will take place. Immunoglobulins also participate in the The Nobel Prize for Medicine was given in 1996 innate immune response. B1 B cells produce to Peter Doherty and Rolf Zinkernagel for the immunoglobulins which are polyspecifi c with demonstration that this “MHC restriction” was relatively low affi nity for their antigen, called an

invariant feature of activation of murine cyto- “natural” antibodies. These molecules are not toxic T cells in the killing of the lymphocytic the product of the extensive genetic manipula- choriomeningitis virus. The precise molecular tions described above and are encoded from mechanisms by which this MHC restriction is germline sequences, and circulate at all times under active investigation, but it was clear that in ready for interaction with any pathogen that the adaptive immune response activation of spe- might enter the body. Many natural antibodies cifi c T cells must be in the “context” of MHC are specifi c for the sugar galactose and other molecules, i.e., require processing of antigen by carbohydrate antigens. These natural antibod- APCs and presentation of antigenic peptides to T ies, consisting primarily of IgM and IgG3, which cells on the MHC molecule. Another clinically are strong activators of complement, do not important role of MHC molecules is their impor- require prior exposure to any pathogens; many tance in transplantation since the smaller the dif- of them recognize epitopes common to bacteria. ference in MHC between a transplant and the Their binding to bacteria, and local activation of recipient, the less the likelihood of transplant complement, allows the local participation of rejection. Major problems with the MHC result granulocytes and other cells and effector mole- in immunodefi ciency syndromes, one of which is cules of the innate immune response. the “bare lymphocyte syndrome” (see Inset 1 .4 ). 2 The Components of the Healthy Immune Response 11 Cytokines are generally diffi cult to categorize, Inset 1.4 MHC and Immune Defi ciency—Bare but large groups include: Lymphocyte Syndrome (BLS) – Interleukins, which act primarily upon white At-risk population . Rare genetic disease. cells – Interferons, which “interfere” with viral repli- Cause . This is caused by a variety of muta- cation in cells targeted by these cytokines tions which result in the absence of MHC – Members of the TNF superfamily, and molecules, usually caused by mutations in – Hematopoietic growth factors. genes outside of the MHC, frequently criti- Interferons will be discussed at length in cal transcription factors. One of these is Chap. 7 . The TNF superfamily has been targeted class II transactivator (CIITA). BLS falls extensively by multiple products in the treatment under a classifi cation of immune defi cien- of rheumatoid arthritis (see Inset 1 .5 and Fig. 1.6 ). cies called severe combined immunodefi - Cytokines function by binding to specifi c recep- ciency (SCID). tors present on their cellular targets. Cytokine Symptoms and signs . There is extreme sus- function then is dependent not only on concentra- ceptibility to viral, bacterial, and fungal infec- tion of the cytokine in the extracellular space but tions. Thus, the usual presentation is an infant also the concentration and proper function of or toddler with frequent, severe infections. the cytokine receptors on the target cell. An example of the interaction of a cytokine with its Morbidity/mortality . High. Death from opportunistic infections is common. Treatment . Bone marrow transplantation is the only curative treatment. Supportive Inset 1.5 Rheumatoid Arthritis; Treatment treatment with IV immunoglobulin and with Cytokine Blockers chronic treatment for common infections At-risk population . Very common disease, such as pneumocystis are used. affl icting 1% of the general population, women more frequently than men. Cause . The cause of rheumatoid arthritis is 2.2.3 Cytokines unknown; it results in progression infl am- Cytokines are small-to-moderate-sized proteins mation and damage to joints throughout the which serve as communication molecules body. between cells; they usually operate at very short Symptoms and signs . Patients have pain, range. One of the fi rst groups of cytokines swelling, and limitation of movement of described were interleukins, with IL-1 having joints throughout their body. one of the longest histories [5 ] . This cytokine has many roles and was described in the 1950s as one Morbidity/mortality . The pain and decreased of the “endogenous pyrogens,” substances that use of RA can be highly disabling. could be transferred from one animal to another Treatment . The mainstay of therapy for to cause fever. Cytokines generally are secreted many years has been immunosuppressives by cells after activation and impact on other cells such as methotrexate. Recently, therapies via cytokine-specifi c receptors. The fi eld of which target the proinfl ammatory cytokine cytokines has experienced explosive growth in TNF-a have been developed. They include the past 30 years, and now cytokine antagonists infl iximab, adalimumab, certolizumab, and or recombinant cytokines are increasingly used golimumab which are monoclonal antibod- in therapy of a wide range of diseases; the bio- ies specifi c for TNF- a and etanercept, logic therapy most commonly used in treating which is a fusion protein of a soluble TNF neuroimmunological disease is the cytokine, receptor linked to human IgG1 Fc. interferon-b (see Chap. 7 ). 12 1 Immunology for the Non-immunologist Fig. 1.6 Rheumatoid arthritis. This disease is a crippling, painful disease of joints in which drugs targeting the cytokine tumor necrosis factor-alpha (TNF- a ) have been effective receptor, and its downstream consequences, will The terms “infl ammatory” and “immune- be analyzed in greater depth in Chap. 7 when mediated” are sometimes used interchangeably, interferon-b ’s interaction with interferon-a – b often because usually there is an increased pres- receptor (IFNAR) will be highlighted. ence of mononuclear cells such as lymphocytes Cytokines are felt to be critical molecules in and macrophages in both processes. However, infl ammation. Infl ammation is usually defi ned by they are not synonyms. For example, myasthenia the physical fi ndings on examination learned in gravis, which is clearly immune-mediated in that Latin by every medical student: r ubor (redness), it is caused by autoantibodies to the nicotinic ace- calor (raised temperature), t umor (swelling), tylcholine receptor (see Chap. 9 ), is not usually dolor (pain), and f unctio laesa (loss of function). considered an infl ammatory disease, since there Alternatively, infl ammation is sometimes in addi- is no redness, swelling, heat, pain, or infl ux of tion defi ned by fi ndings on microscopic examina- mononuclear cells. “Autoimmune” is also used tion of tissues, where the hallmark is infi ltration loosely with the above terms, but this also should of tissue by cells of the immune system such as have a restricted meaning as discussed in greater the neutrophils, monocytes, and lymphocytes depth in Chap. 3 . described above. Since joints are easily accessi- ble to examination, it is relatively easy to measure 2.2.4 CD Antigens the infl ammation of arthritis, while infl ammation CD antigens are surface molecules that are used within the nervous system is much harder to to characterize immune cells. Sometimes, a given examine, and for the latter, the fi ve cardinal signs functional subset of immune cells can be identi- described above do not apply in full. However, fi ed by these molecules. For instance, cytotoxic T functio laesa (loss of function) is defi nitely one cells usually have the CD8 protein on their sur- of the important fi ndings of neuroinfl ammation, a face, so these cells are referred to as “CD8+” point which will be further discussed in some of cells. Since all T cells have the CD3 marker, the neuroimmunological conditions described cytotoxic T cells can be separated from a wide below. TNF- a has been implicated in infl amma- variety of other cells by their combination of tion (see above), but other cytokines are also markers, CD3+CD8+. CD markers on cells are important, including interferon-g and interleukins usually identifi ed by monoclonal antibodies 1, 6, and 8, and TGF-b . tagged with a fl uorescent material identifying the References 13 Table 1.3 CD markers expressed by both lymphocytes and endothelial Cell category CD marker cell surfaces throughout the body, and the extent T cells CD3 of expression of these molecules helps to regulate Helper T cells CD4 where mononuclear cells ingress and egress the Cytotoxic T cells CD8 circulation. Another group of molecules that B cells CD19, CD20 affect lymphocyte traffi cking are sphingosine-1- B1 cells CD5 phosphate and its receptors explained in more Memory B cells CD27 detail in Chap. 19 . Dendritic cells CD8, CD11 2.2.6 Complement Complement is not a single molecule but a collec- CD marker of interest. After reaction of these tion of over 25 proteins which work together to labeled antibodies with the cells, the number of “complement” the ability of antibody to kill a CD+ cells can be determined using a technique pathogen. The initiation of the complement cas- called fl uorescent-activated cell sorting (FACS) cade occurs when an antibody binds to the patho- in which the labeled cells are rapidly passed gen. The end result is the activation of the membrane through a tube past a sensor which detects the attack complex (MAC), which is able to damage fl uorescence. This technology has been a great membranes and results in the death of the patho- advance in characterizing immune cells and gen. CD59, which is present on human cells, inhib- allowing their separation into various categories. its the MAC to prevent lysis of “self” cells, but A list of common immune cells and their CD some viruses, such as HTLV-1 and cytomegalovi- markers is found in Table 1 .3 . rus, make use of CD59 to prevent human-activated complement from lysing them. Another pathogen 2.2.5 Cell Adhesion Molecules which utilizes complex pathways to avoid host kill- When direct cell-to-cell interactions are essential, ing by complement is B orrelia burgdorferi , the immune cells, as well as other types of cells, uti- causative agent of human Lyme neuroborreliosis, lize a class of molecules called cell adhesion which is able to express a variety of complement molecules (CAMs). CAMs are a large class of inhibitors, and upregulates complement inhibitors molecules which generally share the following specifi c for the animal it is infecting [6 ] . characteristics. They have three domains: extra- cellular, transmembrane, and intracellular. The extracellular domain interacts with other cells, References usually via CAMs on those other cells, or alterna- tively interacts with the extracellular matrix. In 1. Gershon RK, Kondo K. Infectious immunological tol- erance. Immunology. 1971;21(6):903–14. addition, the expression of CAMs is generally 2. Gershon RK, Cohen P, Hencin R, Liebhaber SA. not constitutive, but inducible, often by cytokines Suppressor T cells. J Immunol. 1972;108(3):586–90. which upregulate or downregulate CAMs. 3. Cantor H. Reviving suppression? Nat Immunol. Although there are a number of structurally dif- 2004;5(4):347–9. 4. Corthay A. How do regulatory T cells work? Scand J ferent subclasses within the CAMs, such as those Immunol. 2009;70(4):326–36. called selectins , immunoglobulin superfamily, 5. Dinarello CA. Immunological and infl ammatory func- and cadherins, the class of CAMs most directly tions of the interleukin-1 family. Annu Rev Immunol. relevant to the clinical neuroimmunologist is in 2009;27:519–50. 6. Bykowski T, Woodman ME, Cooley AE, et al. Borrelia the subclass of CAMs called integrins. Alpha-4 burgdorferi complement regulator-acquiring surface integrin is the molecule targeted by natalizumab, proteins (BbCRASPs): expression patterns during the a therapeutic monoclonal antibody utilized in MS mammal-tick infection cycle. Int J Med Microbiol. therapy, which will be discussed in greater depth 2008;298 Suppl 1:249–56. 7. Hopkins DR. The greatest killer: smallpox in history. in Chap. 7 . Alpha-4 integrin and other CAMs are Chicago: University of Chicago Press; 2002. ISBN essential in lymphocyte traffi cking. CAMs are 0226351688. Neurology for the Non-neurologist 2 T he purpose of the nervous system is to interact While accounting for only 2% of body weight, with the environment to promote survival and the brain utilizes approximately 20% of the total reproduction. Thus, the nervous system must energy expenditure. receive sensory inputs, the central nervous sys- tem (CNS) must “process” these inputs as well as internal signals and must respond via appro- 1 Organization of the Nervous priate outputs many of them related to muscle System movement. CNS “processing” includes such complicated phenomena as consciousness, The nervous system is generally divided into emotion, and memory. The complexity of the the CNS, consisting of the brain, brain stem, nervous system is immense, a fact demonstrated cerebellum, and spinal cord, and the peripheral by the expanding population of scientists nervous system (PNS), consisting of the nerve involved in its study. The annual meeting of the roots, plexi, peripheral

nerves, the neuromuscu- Society of Neuroscience, basic scientists lar junction, and the muscle. The fl ow of sen- involved in the study of the nervous system, sory information is from the periphery toward regularly attracts over 30,000 attendees. More the brain, and the motor output is from the brain clinically oriented neurology research meetings peripherally. This “brain outward” fl ow of attract thousands of neurologists, physicians who motor output in the nervous system is also care for patients with diseases of the nervous called “rostrocaudal” fl ow. A small minority of system. Since the focus in this chapter is neuro- sensory inputs with motor responses, requiring logical disease, rather than normal neurological great speed, can bypass the brain and are called function, there is not much basic neuroscience refl exes. here, but the basis of all neurology is neurosci- ence, and the distinction between the two fi elds is somewhat artifi cial. 1.1 Electrical Nature: Nerve The human nervous system, as well as that of Transmission and nonhuman primates, is an aberration among ani- Neurotransmitters mals in its size and extravagant energy expendi- ture. One of the differences in the nervous system The nervous system is electrical, and information of primates relative to that of other animals is its is composed of electrical signals which are trans- dependence on vision instead of smell; the visual mitted along nerve cells or across synapses. The system requires a large amount of brain, but pro- fi rst demonstration that the nervous system was vides signifi cant survival advantages to primates. electrical was by Luigi Galvani, an Italian physician, A.R. Pachner, A Primer of Neuroimmunological Disease, 15 DOI 10.1007/978-1-4614-2188-7_2, © Springer Science+Business Media, LLC 2012 16 2 Neurology for the Non-neurologist in 1771 who demonstrated that an electrical 1.2 Cells of the Nervous System impulse applied to a frog’s leg made it kick. The electrical signal which passes along a nerve is A typical neuron possesses a cell body (often called an action potential or nerve impulse and is called soma), dendrites, and an axon (see Fig. 2.1 ), a very fast, transient change in voltage across the arranged in a variety of confi gurations. The axon is nerve membrane mediated by specialized mole- the main electrical cable and is highly specialized cules in the membrane, voltage-gated ion chan- for action potential transmission, while the cell nels. The speed of movement of the action body provides the housekeeping functions for the potential averages about 50 m/s in the human or whole cell, and the dendrites communicate with 110 miles/h. The membrane recovers very quickly other neurons via synapses. Axons can be very and can generate many impulses per second. long; in the human, axons traveling in the sciatic These electrical signals are transmitted by spe- nerve, which have their cell bodies in the spine and cialized cells called neurons. Communication extend to the feet, can be four feet in length, while between neurons is accomplished by synapses in many nerve cells in giraffes are much longer. which the arrival of an action potential results in Proteins from the cell body to distal parts of the the release of neurotransmitters, specialized mol- axon are transported along axonal neurofi laments ecules that can be quickly moved and processed, via a class of molecules called kinesins, consid- across the synapses leading to an action potential ered to be “molecular motors.” The axon of most in the downstream neuron. The nervous system neurons, but not the cell body, is covered by uses many different types of synapses which can myelin, which provides insulation. This allows the be differentiated by location within the nervous electrical signal to be saltatory, or hopping, system as well as by the type of neurotransmitter. between specialized unmyelinated areas along the There are many different types of neurons in the CNS, defi ned by their shape and their variety of synapses. One particularly striking and important type of neuron is the Purkinje cell, fi rst described in 1837 by the Czech anatomist, Jan Purkinje, and localized to the cerebellum. This cell is a tar- get in the disease paraneoplastic cerebellar degeneration (see Chap. 14 ). T he human nervous system utilizes a wide variety of neurotransmitters, which for any syn- apse can be considered excitatory or inhibitory in their effect on transmission of the impulse. The most well understood is acetylcholine, mentioned below, which is used both in the central and PNS. The most prevalent neurotransmitter is glutamate, which is usually excitatory, while gamma-amino butyric acid (GABA) is usually inhibitory. GABA is, in addition, an important neurotransmitter for the neuroimmunologist because GABA agonists, such as baclofen, are used in the treatment of spasticity caused by the most common neuroim- munological disease, multiple sclerosis (MS) Fig. 2.1 Neurons. Nerve cells conduct impulses in a (see Chap. 7 ). Monoamines, such as dopamine, directed manner, from the dendrites through the axon to epinephrine, and norepinephrine, are also impor- the nerve ending. The position of axons and dendrites relative to the cell body and to each other may vary tant neurotransmitters; the adrenergic agonist (Wikimedia, public domain, at h ttp://commons.wikimedia. tizanidine is also used in MS. org/wiki/File:Dendrite_%28PSF%29.png ) 1 Organization of the Nervous System 17 axon called nodes of Ranvier, which are present at intervals along the axon, discovered in 1878 by motor control, ataxia, spasticity, and cogni- Louis-Antoine Ranvier. Myelin is mostly lipid in tive impairment, characterized pathologically content, while the cell body is mostly proteina- by the loss of myelin and oligodendrocytes. ceous, leading to a distinctive whiteness in CNS The cause is a problem with the gene for PLP; areas where myelinated axons are preponderant, these abnormalities range from missense and to grayness where cell bodies mostly occur. mutations to the more common duplications This distinction leads to the commonly used terms of the entire P LP gene, which account for the for the gross appearance of areas within the brain majority of cases of Pelizaeus–Merbacher and spinal cord, “white matter,” where there are disease. The absence of a clear understanding myelinated axons, or “gray matter,” for areas of the role of PLP in healthy myelin function, where there are mostly neurons. Myelin is not a and the wide variety of genetic alterations in component of the neurons themselves, but of spe- this gene, have led to great diffi culty in geno- cialized myelin-producing cells. In the CNS, type–phenotype correlations. myelin is produced by oligodendrocytes (“cells Morbidity/mortality . The disease is fatal in with few dendrites”) and in the PNS, it is produced its most severe form. However, many by Schwann cells fi rst described by Theodor patients with abnormal PLP genetics can Schwann in the nineteenth century. Myelin, a com- have relatively mild disease. One form is plex mixture of lipid and proteins, is different bio- the slow development of spastic paraple- chemically in the CNS versus the PNS. Myelin is gia, called spastic paraplegia 2 (SPG2), essential for effi cient transmission of impulses, which can be quite mild. similar to the way insulation around a wire is essential to effi cient transmission of electricity Treatment . There is no effective treatment. along the wire. Demyelination, the loss of myelin Although gene replacement may help some during diseases is a major feature of two common patients, it will not help most, since the neuroimmunological diseases, multiple sclerosis most common cause is gene duplication. (Chaps. 4 – 8 ) and Guillain–Barré syndrome (Chap. Prevention . Genetic counseling should be 9 ). Most of the protein in central myelin is proteo- made available to the families of patients lipid protein (PLP) which is abnormal in the with PMD or SPG2. genetic disease, Pelizaeus–Merzbacher disease (see Inset 2 .1 ), while in peripheral myelin the major protein is myelin protein zero (MPZ). Both central and peripheral myelins contain myelin Oligodendrocytes are members of a family of basic proteins (MBPs) and myelin-associated gly- cells in the CNS called glia, Greek for “glue”; coprotein (MAG), two proteins which will be dis- other glia are astrocytes and microglia. There are cussed in later chapters. approximately equal numbers of glia and neurons in the human CNS, with the most common glial cell being the astrocyte. The microglia of the brain can be considered the brain macrophages and constitute about 20% of all brain cells. Microglia Inset 2.1 Pelizaeus–Merzbacher Disease: A are derived from hematopoietic precursors, can Genetic Disease of Myelin [4 ] multiply in response to an antigen stimulus, and At-risk population, cause, symptoms/signs . are mobile within the CNS. They are extremely The disease as originally described in changeable, being able to accommodate quickly Germany in the late nineteenth century is a to changes in the microenvironment within the genetic X-linked disease, beginning in CNS. They can assume multiple morphologies infancy, resulting in slow, progressive loss of depending on their level of activation. Astrocytes are not motile and have diverse functions, thought 18 2 Neurology for the Non-neurologist to be mostly in support of neurons. They are able functions of the arms and legs, as well as bowel to communicate with each other using calcium and bladder function. The cerebrum is divided waves through gap junctions; the role of this com- into specifi c lobes, frontal, temporal, parietal, munication is unknown [1 ] . Astrocytes are the and occipital lobes, each of which becomes spe- cells thought to be destroyed fi rst in the neuroim- cialized for certain brain functions, as the brain munological disease neuromyelitis optica (NMO) develops both in utero and after birth. The pri- described in Chap. 6 . mary motor cortex, activated for the purpose of muscle movement, is in the frontal lobe, while the primary sensory cortex, the initial site of cor- 1.3 Structure of the Nervous tical processing of sensory information, is located System: CNS, PNS, Upper in the parietal lobe. Language function is located and Lower Motor Neurons in the temporal lobe, while the very large occipi- tal lobes of the human are devoted to vision and The CNS is divided structurally into three areas its processing. Most motor fi bers cross sides which have different functions: the brain, brain- within the lower part of the brainstem, the medul- stem, and spinal cord (Fig. 2 .2 ). The brain, con- lary decussation, while sensory fi bers cross sisting of the cerebrum and cerebellum, is the within the spinal cord. Thus, a destructive lesion central processing center for sensory input and in the right parietal lobe will result in sensory motor output, as well as the source of conscious- loss on the left side of the body, while damage to ness, memory, emotion, and thought. Just below the left frontal lobe, will result in weakness of the the brain is the brainstem, the processing center right side of the body. The speech centers of the for the cranial nerves, which account for critical brain are located in the left temporal lobe, and functions related to vision, hearing, facial move- destructive lesions there will cause aphasia, loss ment sensation, swallowing, and speech. The of language function. The brain consists of two spinal cord is the local processing center for the broadly different types of neurons, those involved in communication within the brain, called interneurons, which are by far the most common, and those involved in communication with caudal structures, called projection neurons. The CNS is protected from trauma by bone. The brain and brainstem is surrounded by the skull, and the spinal cord by the vertebrae. The vertebral column, also called the spine, consists of 24 articulating vertebrae divided in sections called cervical, thoracic, and lumbar spine. There are nine fused vertebrae below the lumbar verte- brae in the sacrum and coccyx. To provide mobil- ity to the spine, the vertebrae are connected to each other posteriorly through specialized joints and anteriorly are stacked one above the other, with cushions in between called disks. Sometimes disks can become damaged, herniate, and com- press nerve roots or spinal cords (see Inset 6.1 ). The PNS consists of all parts of the nervous sys- tem peripheral to the CNS and includes nerve roots, Fig. 2.2 Organization of the human brain, brainstem, and plexi of roots and nerves (especially the brachial spinal cord in sagittal section, with brain stem highlighted (from Patrick Lynch h ttp://commons.wikimedia.org/wiki/

and lumbar plexus), peripheral nerves, neuromus- File:Brain_sagittal_section_stem_highlighted.svg ) cular junctions, and muscle. Since each muscle is 1 Organization of the Nervous System 19 innervated by one nerve, injury to nerves can be detected by electrical testing of muscles, called progressive nature and the large number of electromyography (see Inset 2 .2 ). The sensation of individuals affected. touch is also transmitted through nerves according Treatment . Generally ineffective. Various to specifi c areas assigned to specifi c nerves, e.g., pain medications, including anticonvulsant two major nerves lead to the hand, the median and type drugs, are used to give some symp- the ulnar, both of which are relatively superfi cial tomatic relief. and susceptible to injury (Inset 2 .3 ). Transmission of signals from motor nerves to muscle is effected Prevention . It is generally believed, but not by a specialized synapse called the neuromuscular proven, that careful control of blood sugar junction, in which the neurotransmitter is acetyl- can delay or prevent diabetic neuropathy. choline, and the receptor on muscle which captures and processes released acetylcholine, is the acetyl- choline receptor (AChR). The AChR is a target of Inset 2.3 Clinical Problem—The Hand: The autoantibodies in the neuroimmunological disease Funny Bone and Carpal Tunnel Syndrome myasthenia gravis (see Chap. 10 ). At-risk population . The human hand is a wonder of biology, but the nerves innervat- ing the hand are prone to injury. Inset 2.2 Clinical Problem—Diabetic Neuro- pathy and the Modern Equivalent of the Cause . The most common neuropathy is a Galvani Experiment transient one, caused by “hitting the funny bone,” when the ulnar nerve is traumatized, At-risk population . Approximately 3% of as it travels through the elbow and passes the world’s population suffers from diabetes, very close to the skin at the medial epicon- a large percentage of which has neuropa- dyle of the humerus. Chronic trauma can thy, i.e., nerve damage causes numbness, lead to permanent injury. Another common weakness, and pain. neuropathy is carpal tunnel syndrome, or Cause . Diabetes mellitus is a disorder of CTS, in which the median nerve is trauma- insulin production or response, and, by tized by constant pressure against the ten- mechanisms that are not understood, is dons in the wrist. associated with injury to neurons in the Symptoms and signs . These two conditions PNS but not in the CNS. lead to numbness and tingling in the hand, Symptoms and signs . Patients with diabetic the particular area of which depends on the neuropathy typically have symptoms in a innervation associated with the nerve. “stocking-glove” distribution, usually con- Morbidity/mortality . Each of these condi- sisting of pain, numbness, and tingling. As tions, which are very common, can cause the disease worsens strength in the legs and dysfunction of the hand and are common then arms decreases, and walking can be causes of disability in our society, where impaired. working with hands, especially keyboards, Patients with diabetic neuropathy can be has become so important. diagnosed using electrical stimulation of tis- sue by electromyography/nerve conduction Treatment . Surgery can result in the protec- (EMG/NCV) studies, a commonly used neu- tion of the nerve from future injury. rological test which is a modern modifi ca- Prevention . Repetitive trauma to the arm tion of Galvani’s stimulation of the frog leg. can be hard to prevent but some simple Morbidity/mortality . The burden to society measures such as using cushioned arm rests of this disease is substantial, because of its may be helpful. 20 2 Neurology for the Non-neurologist Table 2.1 C linical differences between UMN and LMN nerve V; and hearing via cranial nerve VIII. lesions Touch, position, and vibration sense in the body Characteristic UMN LMN come to the brain from peripheral nerves to the Location of injury CNS PNS (except spinal cord and then via the spinothalamic tract for anterior to the brain. The sensory inputs come from spe- horn cell in spinal cord) cialized receptors called mechanoreceptors for Strength Decreased Decreased touch and vibration, including Meissner’s cor- Muscle tone Increased Decreased puscles, Pacinian corpuscles, and Merkel disk Muscle bulk Normal Decreased receptors, and nociceptors for pain. Position Deep tendon refl exes Increased Decreased sense, identifying position in space with or without Sensory abnormalities Variable Variable movement, is mediated by a group of specialized receptors in muscles, tendons, and joints. The CNS is surrounded by a number of mem- The motor system of the body can also be branes. The one immediately overlying the CNS conceptually divided into upper motor neuron parenchyma is the thin and delicate pia mater, (UMN) and lower motor neuron (LMN) territo- which accompanies blood vessels as they pene- ries. UMNs are always in the CNS and project trate into the brain; the pia mater is a part of the onto LMNs in the brain stem spinal cord. The neurovascular unit [ 2 ] . The neurovascular unit is anterior horns of the spinal cord contain the cell a structure composed of components of both bodies of these LMNs which send axons that blood vessels and CNS cells that determines, innervate muscles. Most diseases selectively among other things, the blood–brain barrier target one location in the CNS and frequently (BBB) and is further described in Chap. 3 . The have distinctive UMN or LMN clinical presen- BBB and the blood–CSF barrier consist of cellu- tations (Table 2 .1 ). One disease that has a com- lar barriers between blood and CNS parenchyma bination of UMN and LMN fi ndings is that prevent the easy fl ow of large or highly amyotrophic lateral sclerosis (ALS) which dam- charged molecules between the blood and the ages anterior horn cells and also UMN pathways CNS. Between the pia and the next layer, the within the spinal cord (see Inset 2 .5 ). Stroke and arachnoid mater, is a space called the subarach- multiple sclerosis which are CNS disorders noid space. Over the arachnoid is the thick dura manifest only UMN fi ndings. mater, and the space under the dura is thus called T he dominant sensory input in humans is the subdural space. The spaces defi ned by these vision, a characteristic that distinguishes pri- membranes are used frequently in describing mates from most other animals. A large part of pathological problems, especially bleeding. the human CNS is devoted to vision and its pro- Bleeding within the brain can either be localized cessing. The optic nerve, which carries signals to the brain parenchyma and not spread else- from the retina to the brain, is actually not really where, in which case it is considered an intrace- a true nerve, but an extension of the CNS. The rebral hemorrhage (ICH), or it can be restricted optic nerves, i.e., cranial nerves II, lead to the to the subarachnoid space [subarachnoid hemor- occipital lobe where visual images are processed; rhage (SAH)] or subdural space [subdural hem- the occipital lobe is the only part of the brain orrhage (SDH)]. devoted entirely to one function, vision. The brain is suspended in a fl uid, called cere- Infl ammation of the optic nerve is common in brospinal fl uid (CSF). After being produced by neuroimmununological diseases, especially mul- ependymal cells, epithelial cells that line the ven- tiple sclerosis (see Chap. 4 ) . Optic nerve infl am- tricles, this clear, colorless fl uid, circulates around mation is called optic neuritis and results in the the CNS in the subarachnoid space, i.e., between loss of vision and eye pain. Smell is brought to the arachnoid and pia maters, and eventually the brain from the nose via cranial nerve I, the becomes resorbed by the arachnoid villi or olfactory nerve; touch on the face via cranial drained into lymphatics. In many diseases of 2 The Neurological Evaluation 21 Table 2.2 Some examples of CSF abnormalities in dysfunction of gray matter in the brain affecting disease processes concentration, attention, memory, recall, etc. are Disease CSF abnormality said to have an encephalopathy. Next, the cranial Infl ammation (e.g., Increased number nerves (CNs) are tested: fi rst, the optic nerve, CN encephalitis) of white blood cells II, is tested by the examiner using an ophthalmo- Infection (e.g., pneumoccal Presence of the pathogen scope, a small hand-held instrument, looking at meningitis) the optic nerve head on fundoscopic examination, Cancer (e.g., lymphoma) Presence of cancer cells Bleeding in the brain Presence of blood then by assessing vision. Eye movements are then (e.g., burst aneurysm) checked, usually by having the patient follow the Increased pressure in the Increased pressure examiner’s moving fi nger. Abnormalities in the brain (e.g., hydrocephalus) conjugate movement of the eyes are common and result in the symptom of double vision, also called diplopia; sometimes diplopia is not present, but instead of smooth pursuit of a moving fi nger, the the nervous system, there are characteristic eye movements occur in jerky, oscillating move- abnormalities of the CSF (see Table 2 .2 ), and the ments called nystagmus. Eye movement testing, physician can easily sample CSF by performing a and testing of the pupillary response to light, tests lumbar puncture in which a needle is inserted CNs III, IV, and VI. Normal eye movements are into the subarachnoid space. conjugate, meaning each eye is moved equiva- lently. Conjugate eye movement can be impaired either by a lesion affecting one cranial nerve or by lesions of the brainstem where there are extensive 2 The Neurological Evaluation connections among cranial nerves to allow for conjugate eye movements. The medial longitudi- 2.1 Neurological Examination nal fasciculus (MLF) is one of the connections in the brain stem and is often injured in multiple W hen disease results in neurological symptoms, sclerosis (see Chap. 4 ). CN V is assessed by deter- neurologists are frequently called to evaluate the mining the presence of normal facial sensation patient, identify the diagnosis, and recommend and under some circumstances normal corneal appropriate therapy. The initial evaluation con- refl ex, the rapid shutting of the eyelid when the sists of obtaining a history, and performing a neu- cornea is touched. Movement of the face tests CN rological examination. Diagnoses entertained VII, and hearing tests CN VIII. CN X is tested by after this evaluation are further pursued, if neces- determining that the palate moves normally and sary, by laboratory testing, including blood test- the voice is normal. CN XI is tested by measuring ing, imaging, and other tests. the strength of the sternocleidomastoid and trape- N eurological symptoms usually consist of dif- zius muscles, two large muscle groups of the neck, fi culty with some aspect of nervous system func- while CN XII controls tongue movement. The tion that we normally take for granted. The most motor system is tested by evaluating the strength common are problems with ambulation, coordi- of proximal and distal muscles in the four extrem- nation, strength, and the sensory functions of ities, and by testing muscle tone and bulk. vision or touch. Humans are normally awake, Coordination is tested by analysis of the ability to alert, and can perform diffi cult cognitive tasks; perform well-controlled movements such as rap- neurological disease can impair level of alertness idly moving the fi nger from the examiner’s fi nger and interfere with cognition. to the patient’s nose. The sensory system is then The fi rst part of the neurological examination examined using tests of light touch, vibration, involves assessing higher cognitive functions, position sense, and pin prick. Deep tendon refl exes sometimes utilizing the “Mini-mental Status” are then tested in the arms and legs, followed by examination [ 3 ] . Patients who have diffuse looking for any abnormal refl exes such as the 22 2 Neurology for the Non-neurologist Babinski or Hoffman. The Babinski refl ex is a The combination of the history and neurologi- time-honored bedside test in neurology, initially cal examination will allow the neurologist to developed by Joseph Babinski, a late nineteenth begin answering the two most critical questions century French neurologist, to differentiate psy- when faced with a patient with neurological chiatric from neurological disease (Inset 2 .4 ). symptoms: where and what? Where is the lesion? Injury to descending tracts in the brain or spinal And, what is the most likely process causing dys- cord result in increased deep tendon refl exes and function there? For instance, the

sudden onset of increased muscle tone. Gait is then tested, includ- a left body weakness and sensory loss in a ing walking one foot right before the other (“tan- 70-year-old man with a long history of vascular dem gait”); inability to perform tandem gait disease, hypertension, smoking, and diabetes because of problems with balance is called ataxia, would most likely be a right cerebral stroke, a common problem in multiple sclerosis. The while the location would be the same for a inability to walk well because of weakness or 30-year-old woman with no medical history, but ataxia or abnormal muscle tone is a characteristic the lesion causing it might be more likely to be of many neuroimmunological diseases and is the multiple sclerosis rather than a stroke. function most important in determining the extended disability status score (EDSS), a disabil- ity scale used for measuring multiple sclerosis 2.2 Imaging of the Nervous System (see Chap. 4 ). The neurologist frequently will confi rm the likely diagnosis by some further testing. The standard tool for imaging the nervous system is computer- Inset 2.4 Differentiating Between “Structural” ized tomography (CT) scanning, fi rst available and “Psychiatric” Disease—The Babinski Refl ex for patients in 1972, which involves computer Bizarre behavior is frequently caused by analysis of X-ray signals. Almost all hospitals in psychiatric disease, especially schizophre- the USA have CT scanners. Another method of nia, which has a lifetime prevalence in the imaging is magnetic resonance imaging (MRI), population of between 0.5 and 1%. which does not use X-rays, but instead magneti- However, behavior changes can also be zation as the primary source of signal. The prin- called by “structural” neurological dis- ciple for most types of MRI scans is that the water eases, such as tumors and infections of the molecule is a dipole with the hydrogen nuclei brain. Neurologists often struggle with producing a magnetic fi eld after being aligned by making the proper diagnosis. They fre- an induced magnetic fi eld or radiofrequency sig- quently use a test described in 1896 by nals. The combination of the magnetic fi elds, Joseph Babinski, a French neurologist of the radiofrequency signals, and the timing of Polish origin, who practiced with Charcot the scanning creates many potential ways to at the Saltpetriere in Paris. The Babinski image living tissues. MRI is generally more sen- test involves stroking the sole of the foot, sitive and specifi c than CT scanning and does not and eliciting a movement of the toe upwards have the potentially damaging effect of radiation in individuals with damage to the corti- dose caused by X-rays. However, it is much more cospinal tract, but downward movement in expensive than CT scanning, and is not as widely the absence of such injury. A positive available. The MRI has been especially useful in Babinski, i.e., an extensor upward move- multiple sclerosis; its use in that disease will be ment of the toe, can be a very early sign of discussed extensively in later chapters. A type of injury, but will be absent, i.e., a fl exor MRI called functional MRI may also become downward movement, in patients with psy- clinically useful in assessing recovery after CNS chiatric disease. injury (see Inset 2 .5 ). CT and MRI scan not only show areas of abnormality by their characteristic 2 The Neurological Evaluation 23 signals but also show the absence of CNS tissue; many disease processes, especially those with a the lips, sometimes called functional degenerative component such as Alzheimer’s dis- cortical remapping. ease and multiple sclerosis, lead to the loss of The fi eld of cortical remapping and CNS tissue which is demonstrable on imaging determining whether humans can build as atrophy. new structural connections is an active and in 2011, a very controversial area. One of the tools of investigators in this fi eld is functional MRI, in which activation of brain regions can be imaged by the Inset 2.5 Clinical Problem—Recovery After increased blood fl ow caused by increased CNS Injury, Neural Plasticity, the Contribution neuronal activity. of Kittens and Phantoms, and Functional MRIs C NS injury is unfortunately a common problem in the society, with motor vehicle accidents and strokes common causes. Some atrophy is due not primarily to death at Neurons do not divide, and dead neurons the site of the atrophy visualized on imaging, but generally cannot be replaced with new neu- may be due to injury to a part of the nerve cell rons. Thus, recovery of function after injury distant from the atrophy. Wallerian degeneration must involve processes other than growth is axonal atrophy below an area of injury to the of new cells. One of these mechanisms is neuron. If the axonal injury is healed the healthy neural plasticity, in which neurons involved axon above the injury can grow back into the in other functions change to pick up the lost intact neurolemma, the hollow myelinated tube of functions from injury. The concept of plas- the nerve, which is part of the Schwann cell or ticity and other processes are obviously of oligodendrocyte, and may not be affected by the considerable interest to clinical neurosci- injury. Sometimes complete recovery can occur if entists who wish to optimize recovery after Wallerian degeneration goes smoothly and the injury, but our knowledge of these pro- neurolemma remains intact and healthy. This hap- cesses remains relatively primitive. pens more commonly in PNS than CNS diseases. It was thought that brain regions were “hard-wired,” but this was proven wrong by pioneering experiments in the 1960s 2.3 EEG and EMG and 1970s by Hubel and Wiesel [5 ] . In kit- tens who from birth had one eyelid sewn Many patients with brain disease develop seizures shut, the primary visual cortex receiving or impairment of the electric signals in their brains inputs from the functioning eye took over detectable by the measurement of electric fi eld the areas that normally received input from potentials measured over the scalp, known as the deprived eye. electroencephalography (EEG). Since measure- In individuals who have an amputation, ment is over the scalp and electric fi elds decay rubbing of the face or lips can induce sen- rapidly with distance, the EEG mostly assesses sations perceived as if they were in the cortical neurons close to the skull. Most of the amputated, i.e., absent, limb. This is called fi eld frequencies are about 3–20 Hz, and the phantom sensation, and when it is associ- amplitudes are usually 10–80 m V. The relatively ated with pain, phantom pain. This appears low voltage is due to a great extent from damping to be because of downward shift of the from the skull since the signals from subdural hand area of the sensory homunculus onto electrodes are nearly three logs higher in ampli- the area of face representation, especially tude than those from surface electrodes. Characteristic patterns are seen in normal awake, 24 2 Neurology for the Non-neurologist drowsy, and sleeping adults, and the patterns change depending on age of the patient, and loca- Morbidity/mortality . The disease is fatal, tion on the skull of the electrodes tested. The most usually leading to death in 2–5 years after dramatic abnormalities are seen during seizures diagnosis. when synchronous bursts of activity can be seen Treatment . No treatment has been shown to as spike and wave forms which replace the nor- be effective and there is no way to prevent mal rhythms. EEG-detected seizures may or may the illness. not have associated clinically obvious sequelae. The electrical activity of the nervous system can also be used to detect abnormalities in the recording needle into weak muscles will demon- peripheral system using a test known as electro- strate characteristic abnormalities referable to the myography and nerve conduction velocity testing involvement of these LMNs by the disease in the or EMG/NCV. In EMG, needles are inserted into anterior horn cells of the spinal cord. NCV test- muscles thought to possibly be involved in the ing determines the velocity of nerve conduction pathological process. In a patient with ALS, Lou which for most nerves is approximately 50 m/s. Gehrig’s disease (see Inset 2 .6 ) insertion of a The most dramatic slowing of nerve conduction velocities is seen in conditions which result in the loss of myelin, such as acute or chronic infl am- Inset 2.6 Amyotrophic Lateral Sclerosis— matory demyelinating polyneuropathy (AIDP or UMN and LMN Findings CIDP), conditions discussed in Chap. 9 . In con- At-risk population . An uncommon disease trast, processes which injure axons in the PNS affecting individuals of both sexes usually but generally spare myelin, e.g., the neuropathy between 30 and 50 years old. The annual of diabetes mellitus, will result in lower and incidence is about 1 in 100,000. deformed action potentials out of proportion to slowed nerve conductions. Cause . Unknown. Symptoms and signs . Progressive muscle weakness and atrophy. The disease is often References called Lou Gehrig’s disease. One of the best baseball players ever, Lou Gehrig held 1. Giaume C, Koulakoff A, Roux L, Holcman D, Rouach many records for both batting (most grand N. Astroglial networks: a step further in neuroglial and slams, most homers in a game, etc.) and for gliovascular interactions. Nat Rev Neurosci. 2010; 11(2):87–99. durability (most consecutive games played), 2. Owens T, Bechmann I, Engelhardt B. Perivascular until May 2, 1939, when he benched him- spaces and the two steps to neuroinfl ammation. self and sought medical attention because J Neuropathol Exp Neurol. 2008;67(12):1113–21. of his progressive weakness and was diag- 3. Folstein MF, Folstein SE, McHugh PR. Mini-mental state. A practical method for grading the cognitive state nosed with ALS. His retirement speech at of patients for the clinician. J Psychiatr Res. Yankee Stadium on July 4, 1939 (“I con- 1975;12(3):189–98. sider myself the luckiest man on the face of 4. Garbern JY. Pelizaeus-Merzbacher disease: genetic and the earth”) was one of the most eloquent by cellular pathogenesis. Cell Mol Life Sci. 2007; 64(1):50–65. a sports fi gure. He died of ALS 2 years later. 5. Hubel DH. Exploration of the primary visual cortex, 1955-78. Nature. 1982;299(5883):515–24. Neuroimmunology for the Non-neuroimmunologist 3 After two exceedingly brief reviews of immunology unknown, but is an area of intense study. Thus, at and neurology, we are ready for an exceedingly brief this point in time, neuroimmunology is generally review of neuroimmunology. Neuroimmunology is a study of disease states, and we are hopeful that a nascent fi eld and our understanding of most of the our knowledge will expand into understanding fi eld is relatively shallow. This chapter serves as a normal functions as well. brief historical review of trends in the fi eld and an Given the diffi culty of accessibility of human introduction to the remainder of the book. nervous system tissue, the study of neuroimmu- Neuroimmunology is focused on disease, nology has historically been primarily the study since the nervous system is not thought of as par- of animal and cellular models of disease. This ticipating in immune functions under “normal” focus on nonhuman systems has its advantages conditions. There is no neuroimmunological sys- and disadvantages. An advantage is that informa- tem development, unlike its parent systems each tion can be much more rapidly accrued about the of which has their own developing structures, interactions of the immune and nervous systems. cells, and locations. Thus, part of the title of this A disadvantage is that the human nervous system book, “N euroimmunological Disease ,” can be is very different from the nervous system of lower considered redundant, since neuroimmunology is animals, with the possible exception of nonhu- usually thought of in the context of disease. But man primates. Thus, the relevance to humans of this is not surprising for an infant fi eld; immunol- knowledge gained from experiments on neuroim- ogy and neuroscience were both born out of munology in mice, neuroimmunology’s favorite human disease, in attempts to understand dis- animal for models, is not as high as it might be eases such as syphilis and dementias. At some for other organ systems in which there is more of point in the future, the nervous system will be a resemblance to humans. considered an essential functioning part of the normal immune system, and the immune system will

be considered an essential part of the normal nervous system. These overlaps are already being 1 The Beginnings of studied. The autonomic nervous system inner- Neuroimmunology: Post- vates lymphoid organs, but how this functions in vaccinial Encephalomyelitis normal functioning of the immune system is unknown. Conversely, a classical “immune” cell, The fi eld of neuroimmunology had its concep- the microglial cell, is a normal constituent of the tual beginning in the late nineteenth century dur- central nervous system, in fact constituting about ing work on rabies, a fatal neurological infection 20% of the total number of glial cells, but its (see Chap. 12 for more on rabies), when it was function in normal CNS function is essentially found that some individuals developed severe A.R. Pachner, A Primer of Neuroimmunological Disease, 25 DOI 10.1007/978-1-4614-2188-7_3, © Springer Science+Business Media, LLC 2012 26 3 Neuroimmunology for the Non-neuroimmunologist Table 3.1 Experimental models of presumed neuroimmunological disease induced by immunization of animals with nervous system components Immunization Name of Passive transfer/ Purifi ed antigens Cellular or Disease with: model active immunization used humoral Animal modeled CNS EAE Both MBP, PLP, MOG, Cellular Multiple ADEM and their peptides PNS EAN Both P0, P2, SGPG, Cellular Rodents GBS, CIDP and their peptides Acetylcholine EAMG Both AChR Humoral Multiple Myasthenia receptor (AChR) gravis CNS infl ammation after the rabies vaccine was The concept that antigens within the nervous administered, i.e., the immune system could system could be purifi ed and used as immunogens damage as well as protect. Although rabies inci- for experimental models has served as a guiding dence has decreased substantially in the early light for the development of multiple animal mod- twenty-fi rst century with the availability of very els in neuroimmunology [2 ] . In the past 50 years, good vaccines, there are still today about 50,000 as immunology made major advances, the num- deaths from rabies worldwide reported per year, ber of models multiplied; the major models have and many rural and suburban areas in the USA been EAE, experimental autoimmune neuritis have persistent reservoirs of rabid wild animals. (EAN), and experimental autoimmune myasthe- When Louis Pasteur and Emile Roux developed nia gravis (EAMG) (see Table 3 .1 ). A variety of the rabies vaccine in 1885, they used desiccated other models have been developed, none of which spinal cords of infected rabbits as the vaccine have been used as extensively as those listed in material. Later rabies vaccines also used CNS the table. A partial list includes: models of neuro- tissue; the Semple rabies vaccine is an inacti- myelitis optica (NMO), limbic encephalitis, vated homogenate of the brain of goats or sheep Lambert–Eaton myasthenic syndrome (LEMS), infected with rabies virus. The Semple vaccine, Rasmussen’s encephalitis, stiff-person syndrome or other vaccines purifi ed from animal CNS, (SPS), and pediatric autoimmune neuropsychiat- which contain CNS material, continues to be ric disorders associated with streptococcal infec- used in some countries, including India, and tion (PANDAS). post-vaccinial encephalomyelitis continues to be Historically, the pathway for new ideas and a clinical problem occurring in about one in 220 new potential treatments in neuroimmunology individuals receiving the Semple vaccine [ 1 ] has been from bench-to-bedside, but over the last usually 2–3 weeks after the vaccine. Post- decade there has been a great deal of new knowl- vaccinial encephalomyelitis, in this case Semple edge gained from testing potential targets in rabies vaccine-associated encephalomyelitis (SAE), human disease, usually using monoclonal anti- is a subset of a group of diseases in humans bodies that have been developed for other dis- called acute disseminated encephalomyelitis eases, and then going back to animal models and (ADEM). The realization that immunization cellular systems when the new therapies have with CNS tissue could induce an infl ammatory demonstrated therapeutic effi cacy [3 ] . One of the encephalomyelitis in humans is the basis for a best examples of this is the B-cell depleting group of neuroinfl ammatory models in experi- monoclonal antibody, Rituximab, which demon- mental animals, collectively called EAE (experi- strated considerable effi cacy in treating MS, and mental autoimmune encephalomyelitis), which has led to a fl urry of research on B cells in MS; have accounted for a large percentage of the MS had previously been considered by many to research effort in neuroimmunology. ADEM and be exclusively a “T cell-mediated disease.” This EAE will be extensively discussed in later chap- “bedside-to-bench” fl ow of information will be ters in this book. discussed at greater length when monoclonal 1 The Beginnings of Neuroimmunology: Post-vaccinial Encephalomyelitis 27 antibody therapy is discussed. Another area in called glia limitans perivascularis. The perivascular which “bedside-to-bench” fl ow of information space, “PVS” in Fig. 3 .2 , is bounded by the has occurred has been in the increasingly broad glia limitans and by the walls of post-capillary fi eld of autoantibodies. Academic neuroimmu- venules. In capillaries of deeper sections of the nology clinical laboratories, which had previ- brain (#12), shown by the black bar, the perivascu- ously been primarily used for the detection of lar space vanishes, and the capillary endothelium autoantibodies in paraneoplastic syndromes (a (“E”), fuses with a specialized cell called the peri- topic to be reviewed in Chap. 14 ), have extended cyte (“Pe”) and then the astrocytic endfeet (white their interest to non-paraneoplastic diseases. The arrows in Fig. 3.2 ) to create a “fused gliovascular most dramatic discovery has been the fi nding this membrane.” Aquaporin 4, the putative autoantigen past decade that NMO, thought to be a rare vari- of NMO (see Chap. 6 ), is found in the astrocytic ant of multiple sclerosis, is actually a disease endfeet. mediated by anti-aquaporin 4 autoantibodies with Normally, in the absence of infection or diagnostic and therapeutic features distinct from infl ammation in the CNS, there is traffi cking of a MS. This “bedside” observation has brought small number of immune cells through the CNS. “bench” researchers to focus on aquaporin chan- Under infl ammatory conditions, traffi cking nels as biologically relevant molecules. increases and cells which have receptors specifi c The animal model that dominates neuroimmu- for new antigens present in the CNS, either spe- nology by sheer numbers is EAE. As of 2010, the cifi c for pathogens in infections or CNS antigens number of articles referenced on PubMed for in EAE, will linger in the CNS and become acti- experimental allergic encephalomyelitis (EAE, vated. As more cells become activated, cytokines also called experimental autoimmune encephalo- are upregulated, as well as a specialized class of myelitis) is 3,554, far outnumbering EAN (219), cytokines, called chemokines which are felt to be and EAMG (461). A major concept in neuroim- key chemoattractant molecules for immune cells. munology critical for the understanding of EAE is The combination of the presence of these chemok- that of communication between the CNS and the ines as well as a transiently breached blood–brain periphery related to the vasculature. The CNS is barrier continue to recruit more cells. Entry of thought to have a relatively primitive innate cells into the CNS appear to be via a two-step immune response available from its own cells, and process. Initially, the cells in the earlier phases of thus must “import” cells from the periphery when neuro-infl ammation accumulate in the perivascu- necessary. In EAE, immune cells are activated in lar space, with few immune cells from the blood the peripheral lymphoid tissues and then enter the entering into the parenchyma. However, as the CNS in increasing numbers. The area of the CNS process proceeds, especially if it is poorly con- in which these peripherally activated immune cells trolled, or unusually strong, more and more enter the CNS in EAE and other neuroimmuno- infl ammatory cells enter into and remain in the logical processes is called the neurovascular unit. CNS parenchyma. The larger blood vessels (#6 in Fig. 3 .1 ), located in Our understanding of the immune response the subarachnoid space (#7), enter the parenchyma within the CNS and PNS remains primitive. of the nervous system from the outside as penetrat- Compared to the power of immune response out- ing vessels (#11). The cell body, also called soma side of the CNS, the immune response within the or perikaryon, of astrocytes near the surface of the CNS appears to be blunted or, under some cir- brain (#1), send out processes which terminate in cumstances, completely absent. For instance, endfeet; endfeet of many astrocytes near the blood foreign tissues, rapidly rejected when placed into vessel, and the subarachnoid space are joined in a the skin, survive for a long time when placed membrane called the glia limitans (#2), which in into the CNS. This led to the concept of immune this location is called the glia limitans superfi cia- privilege of the CNS, i.e., the CNS was felt to be lis. Endfeet connecting to each other near blood incapable of mounting any immune response, vessels deeper within the parenchyma (#13) are and whatever immune activity present was 28 3 Neuroimmunology for the Non-neuroimmunologist Fig. 3.1 The neurovascular unit. (a ) Schematic diagram heads ) or their basement membranes. The fi eld corre- of different anatomic regions from brain parenchyma to sponds to the w hite bar (a ). ( c ) Higher magnifi cation of the skull. Superfi cial vessels of the brain [6 ] are located in the fi eld depicted ( b ) shows the basement membranes. In non- subarachnoid space [7 ] . This compartment is delineated by capillary vessels, at least three basement membranes can the arachnoid mater [4 ] and the pia mater [3 ] . The surface be distinguished: the endothelial membrane (d otted line ), of the brain is completely covered by the astrocytic endfeet the outer vascular membrane (d ashed line ), and the mem- of the glia limitans [2 ] . Toward the subarachnoid space, brane of the glia limitans (d otted and d ashed ). ( d ) these endfeet are designated as glia limitans superfi cialis Ultrastructure of the region corresponding to the b lack bar (A); toward the vessels inside of the brain, they are termed ( a ). (d ) In capillaries (12 in a ), the basement membranes glia limitans perivascularis (B). On their way from the sur- are merged to form a “fused gliovascular membrane” that face to the deep areas of the brain, the vessels take leptom- occludes the perivascular space. (e ) Higher magnifi cation eningeal connective tissue with them, thereby forming of the fi eld depicted (d ). The capillary wall consists of perivascular spaces [1 0] , which remain connected to the endothelium [E], endothelial basement membrane (d otted subarachnoid space. 1 indicates perikaryon of an astrocyte; line ), and Pe. The gliovascular membrane is shown by a 2 glia limitans superfi cialis; 3 connective tissue of the pia continuous b lack line. It is directly apposed to the glia mater (inner layer of the leptomeninges); 4 arachnoid limitans. Astrocyte processes of the glia limitans are indi- (outer layer of the leptomeninges); 5 subarachnoid connec- cated by a rrowheads . The a rrows ( c and e ) point to tight tive tissue (trabeculae arachnoideae); 6 subarachnoid ves- junctions between endothelial cells. The overlap of adja- sel; 7 subarachnoid space; 8 dura mater (pachymeninges); cent endothelial cells is a hallmark of the BBB and is evi- 9 neurothelium; 10 perivascular space; 11 penetrating ves- dent in the capillary but not in the venule. E endothelial sel; 12 capillary; and 13 glia limitans perivascularis. (b and cell, L lumen, MC mural cell, an intermediate form between c ) Ultrastructure of the PVS, which is bordered by other smooth muscle cell and pericyte, Pe pericytes, PVS perivas- walls of a postcapillary venule and the glia limitans (a rrow- cular space completely dependent on cells recruited into the that of other tissues, and their preferential hom- CNS. However, newer concepts are emerging, in ing to B-cell follicles in cervical lymph nodes which it is clear that the immune response in the may be responsible for the known “B-cell domi- CNS is simply different, and that the term nance” of immune responses within the CNS [ 4 ] . “immune privilege” is misleading. For instance, In addition, neurons and glial cells likely regulate the traffi cking

of dendritic cells, cells critical for the function of macrophages and lymphocytes adaptive immune responses (see Chap. 1 ) within once they enter the CNS [ 5 ] . Thus, the perceived the CNS, is very different within the CNS from “privilege” is one of active regulation, rather 2 Semple Rabies Vaccine Autoimmune Encephalomyelitis: Temporal Progression… 29 with Semple rabies vaccine. For most antigens, the route is important since antigen processing is different at different sites of entry. In SAE, the route is subcutaneous, so lymph node drainage (see below) is to lymph nodes draining the skin in areas of injection. Entry of antigens or pathogens can be by a variety of other routes the most com- mon being gastrointestinal and respiratory. These entry points have their own highly developed lymphoid tissue, called gut-associated lymphoid tissue (GALT) and bronchus-associated lym- phoid tissue (BALT) which are specialized to deal with antigens coming in via these routes. Fig. 3.2 Positioning for a lumbar puncture. The patient can be either in the lateral decubitus position, or in the sitting position, as in this patient. The needle is inserted into the subarachnoid space midline in the interspace 2.2 Stage 2. Days 0–7: Lymph Node between the fourth and fi fth lumbar vertebrae, at the level Drainage and Processing of of the iliac crest Antigen in Peripheral Lymph Node than passive absence, not surprising given the dangers that unregulated immune responses Semple vaccine is injected subcutaneously at would pose to the critical communications and multiple sites, frequently in the abdomen, so control systems within the CNS [ 6 ] . the antigen would be initially present initially in the subcutaneous fat, and then be drained into draining lymph nodes including those in 2 Semple Rabies Vaccine the inguinal area. As described above, Semple Autoimmune vaccine is not a pure substance, but a mixture of Encephalomyelitis: Temporal materials containing antigens including those Progression. Interplay Between in the rabies virus as well as CNS antigens such the Nervous and Immune as myelin basic protein (MBP) [7 ] from the Systems sheep brain material in the vaccine. These rabies and brain antigens are “processed” by The development of antigen-specifi c T and B dendritic cells and other “antigen-presenting” cells from lymphocyte precursors can only occur cells, mechanisms which begin locally, i.e., in lymphoid tissue. A good initial illustration of subcutaneously, and continue in the lymph the interplay of peripheral lymphoid tissue and node. The local lymph node is the site where the CNS can be found in the “classical” neuroim- the antigen-containing dendritic cells home munological disease, Semple rabies vaccine usually via lymphatic vessels. During the fi rst autoimmune encephalomyelitis (SAE), as the week, antigen-specifi c lymphocytes, B cells disease proceeds in stages. and T cells, including myelin-specifi c cells, are being activated, leave the lymph node via lym- phatic vessels, enter the blood via the thoracic 2.1 Stage 1. DAY 0: Exposure to the duct, and start circulating in the bloodstream. Antigen A particularly important subset of T cells in the early response is the Th17 cell, a helper T cell The onset of many neuroimmunological and neu- which secretes IL-17. The differentiation and roinfectious diseases can be traced to a specifi c expansion of this T-cell subset is favored by the inciting event that disrupts homeostasis. In SAE, presence of the cytokines transforming growth the inciting event is the injection of the human factor-b (TGF-b ) and IL-6. 30 3 Neuroimmunology for the Non-neuroimmunologist 2.3 Stage 3. Days 7–10: Recruitment of cytokines by these myelin-specifi c cells activates of Myelin-Specifi c Lymphocytes other cells locally; an important consequence of into the CNS this activation and cytokine release is that the blood–brain barrier is compromised in areas of Lymphocytes normally traffi c throughout the infl ammation. body and only stop either in secondary lymphoid organs or in tissues in which they encounter anti- gens with which their antigen receptors react. As 2.4 Stage 4. Days 10–20: Maximal part of the usual lymphocyte traffi cking through Infl ammation with Involvement the CNS, lymphocytes traffi c through the CNS at of Local CNS Immunity, low levels, i.e., under normal circumstances, Including Cervical Lymph Nodes lymphocytes enter, and then leave the CNS because there are no antigens with which the In this fourth stage of SAE, the processes outlined lymphocytes interact. However, in SAE due to in stage 3 expand in amplitude and occur simulta- the myelin present in the immunizing material, neously, in multiple areas of the CNS, in the brain, there are newly formed myelin-specifi c lympho- brain stem, and spinal cord, due to traffi cking and cytes. These lymphocytes stop within the CNS, replication of myelin-specifi c lymphocytes. and interact with myelin antigens. In contrast, Symptoms of CNS dysfunction appear, such as those newly formed T cells recognizing rabies weakness, numbness, tingling, and problems with antigens in Semple vaccine continue to circulate vision, balance, bladder and bowel function, since there are no rabies antigens in the CNS in a speech, or the cranial nerves. Cerebrospinal fl uid vaccinated individual. T cells which circulate (CSF) analysis performed during this stage reveals through the CNS are presumed to be effector many white cells in the normally clear CSF. The memory cells, which express little or no CCR7 (a CSF will also contain anti-Semple vaccine anti- chemokine receptor associated with cell traffi ck- bodies, produced by multiple plasma cells, each ing in the lymph node), and which secrete cytok- one making thousands of molecules of a clonal ines and express cytokine receptors. Less is anti-Semple vaccine antibody. The precise mech- known about B cells which traffi c through the anism of injury/dysfunction in SAE is not known, CNS, but the CNS is thought to be “B-cell i.e., we do not really understand how immune friendly” because of the constitutive production activation and infl ammation leads to CNS dys- within the CNS of survival factors for B cells [8 ] . function. Many parts of the CNS can have consid- The cells which traffi c into the CNS are only a erable amounts of infl ammation without resultant very small percentage of total lymphocyte traf- clinical sequelae. fi cking. There are about 500 billion lymphocytes As cells within the CNS die, and dendritic at any time in the human body, and about the cells, macrophage, and other similar cells are same number traffi c through the blood each day recruited into the CNS from the blood, they and go to and through other lymphoid tissues. At encounter a range of breakdown products of the any time, most lymphocytes are found in lymph CNS from the injury. These will include neural nodes, spleen, bone marrow, thymus, and mucosa- antigens present in the original Semple vaccine, associated lymphoid tissue with only a very small but in addition new antigens of human, not sheep number in tissues or in blood at any time [9 ] . or goat origin. Since there will be cross-reactions Cells which contain class II MHC antigens, such because of the similarity of molecules, these mol- as macrophages and dendritic cells from the ecules will likely amplify the infl ammation and blood, as well as microglia within the CNS, pres- extend its duration. ent MBP and other CNS antigens to antigen-spe- The precise manner in which tissue debris is cifi c T and B cells traffi cking through, and these cleared from the CNS, and infl ammatory cells traf- cells become locally activated, and go through fi c, is unknown. Experiments in rats in the late cycles of replication. The release within the CNS 1990s had demonstrated that immune cells from 3 The Tools of the Neuroimmunologist 31 the brain traffi c to cervical lymph nodes [ 10 ] , and then into the circulation, but recent experiments 3 The Tools of the have revealed that another route, i.e., directly into Neuroimmunologist cerebral blood vessels, is also possible. The infl am- mation will be evident to the neurologist as the 1. History . From a carefully obtained history, symptoms experienced by the patient, the abnor- most neurologists can localize where within mal neurological examination consistent with the nervous system the lesion lies, as well as CNS damage, increased number of white cells and determine the most likely few causes of the protein in the CSF after lumbar puncture, and problem. At University Hospital in Newark, abnormal signals of infl ammation and loss of CNS where I practice neurology, in months when I myelin evident on imaging of the brain. attend on service, I consistently can identify the nervous system location and etiology of an injury in 90% of cases by history alone. The 2.5 Stage 5. Days 20 and Later: pace and severity of the symptoms and exac- Recovery erbating/remitting factors are helpful. By probing for problems referable to certain loca- A fter the peak of infl ammatory process in the tions, e.g., speech content problems coming second to third week, poorly understood down- from the left temporal lobe pathology, lesions regulatory mechanisms kick in. It is possible that can usually be accurately localized. A careful a mix of “regulatory” cells, including T cells, B past medical history, social history, and family cells, microglia, and macrophages, contribute to history frequently demonstrate that the patient this downregulation. Cellular debris is cleared being evaluated is at a high risk for certain dis- and T- and B-cell numbers in the CNS decrease. ease processes. Demyelination moderates and then stops, and 2. Examination . A thorough neurological exami- remyelination, which had begin to occur already nation, as briefl y outlined in Chap. 2 , is neces- early in Stage 4, predominates. Clinically, the sary, and often will confi rm the hypotheses patient’s symptoms begin to improve. Patients drawn from the history. Most patients with who survive the sometimes very stormy fi rst few multiple sclerosis, for instance, will have weeks of SAE frequently have a good outcome, involvement of multiple areas of the nervous and many patients return to normal within a few system, with problems with vision, eye move- weeks to months following the onset of the ment, balance, tone, strength, and sensation, disease. which can all be documented on the neuro- As mentioned above, SAE is closely related to logical examination. the other monophasic infl ammatory syndromes 3. B lood analysis . A complete blood count may EAE and ADEM. In EAE, the inciting immune show an increased number of white blood cells stimulus is known because it is an induced exper- consistent with a generalized infection. An imental model, while in the human disease elevated erythocyte sedimentation rate (ESR) ADEM, the inciting antigen is usually not known. would be consistent with a systemic vasculitis, The controversies about the relationships between such as giant cell arteritis. PCR for bacteria the infl ammation and monophasic course of and viruses can be done in the blood, e.g., ADEM and its experimental model EAE and the patients with AIDS have levels of the human human disease multiple sclerosis will be dis- immunodefi ciency virus (HIV) in their blood. cussed in depth in the chapters on multiple scle- 4. CSF analysis . Most patients being considered rosis. Both ADEM and EAE are monophasic for a neuroimmunological disease will undergo diseases with complete or near complete recov- a lumbar puncture (LP) (Fig. 3 .2 ) to obtain ery and no further CNS involvement, while MS and test CSF. Similar to the immune system is a relapsing and progressive disabling infl am- which has its own fl uid (lymph) and its own matory disease. circulation (through lymph vessels), the CNS 32 3 Neuroimmunology for the Non-neuroimmunologist has its own fl uid (CSF) and its own circula- 2. Limited access of infl ammatory cells to the tion, within the subarachnoid space around the parenchyma: In most tissues, there is free brain and spinal cord. Infl ammation within the access of cells from the circulation to an CNS can usually be readily detected by CSF infl ammatory process within the parenchyma; analysis. Some common processes producing this is not true for the nervous system, where CSF abnormalities were summarized in Table the blood–brain barrier and the blood–nerve 2.2 in Chap. 2 . barrier regulate infl ux of cells. The nervous 5. Imaging of the CNS or PNS .

Computerized system regulates these barriers by a variety of tomography (CT) or magnetic resonance mechanisms. It adjusts the levels of adhesion image (MRI) is used to image the brain, spinal molecules required for white cells to attach cord, or other areas of the body. Multiple scle- and enter. It modulates the tightness of the rosis causes a characteristic picture on MRI tight junctions of the endothelial cells. scanning of the brain of loss of myelin in mul- Astrocytes are tightly linked to the perivascu- tiple areas of the CNS associated with breach lar space and are thought to affect the move- of the blood–brain barrier, while, in herpes ment of cells into the parenchyma. simplex virus encephalitis, there is one focal 3. Absence of anatomically defi ned lymphatic area of increased signal in the temporal lobe system: Most tissues are aided in their interac- unilaterally. Infl amed areas of the brain can tion with the immune system by the lymphatic sometimes additionally be detected by inject- system which consists of lymph vessels and ing a dye named gadolinium intravenously lymph nodes. There is no anatomically defi ned during MRI scanning; because of the local lymphatic system in the CNS, although move- breakdown in the blood–brain barrier in ves- ment of CSF and interstitial fl uid through the sels of infl amed areas, gadolinium will appear brain and Virchow-Robins spaces, i.e., the in the parenchyma of the infl amed areas. This perivascular spaces, with subsequent drainage can aid in diagnosis and is commonly used to cervical lymph nodes, subserves some of especially in multiple sclerosis. the role of lymphatics [1 1 ] . 4. The anti-infl ammatory “ tone ” of the CNS: A hallmark of infl ammation is swelling, also 4 Aspects of Infl ammation in called “tumor.” Medical students for 20 centu- Neuroimmunology Unique to ries have learned the four cardinal signs of the Nervous System infl ammation in Latin, fi rst recorded by Celsus in the fi rst century ad : calor (heat), dolor 1. Variability in clinical outcome depending on (pain), rubor (redness), and tumor (swelling). the l ocation within the nervous system of the Swelling in immune-mediated processes such infl ammatory process. In infl ammation of the as delayed-type hypersensitivity (DTH) is T lung or liver or other tissue, location within cell mediated. The brain in adults is encased the tissue will generally not markedly affect by the rigid skull, so swelling in the brain the symptoms and signs of the illness. In neu- leads to increased pressure and potentially roimmunological disease and in neurological fatal complications. This fact may account disease in general, location within the CNS is evolutionarily for the “anti-infl ammatory” extremely important, e.g., infl ammation in the tone of the CNS. The precise molecular causes temporal lobe cortex such as that seen in her- for what has been called “a hostile environ- pes encephalitis, with seizures and headache, ment for T cells” in the CNS is not known, but has a much different presentation than that high levels of cytokines such as TGF-b or seen in infl ammation in the spinal cord, such IL-10 which are usually downregulatory for as seen in myelitis from multiple sclerosis, T-cell functions may be contributing. In con- when the patient loses strength in her legs and trast, swelling in nonneural tissues is gener- loses bladder function. ally not so damaging, and for these tissues, the 5 The Necessity for Great Care in Classifying a Neuroimmunological Disease as “Autoimmune” 33 full range of infl ammation, including tumor, is among the OIs are cerebral toxoplasmosis, allowed. Since it is primarily Th1 and Th17 progressive multifocal leukoencephalopathy, and cells which mediate DTH, and thus swelling, cytomegalovirus polyradiculitis. Tuberculous it is not surprising that there is a relative skew meningitis and varicella zoster virus complica- in the CNS away from these T cells toward the tions, including shingles and myelitis, can also be function of Th2 cells [1 2 ] , which help B cells seen. Fungal infections, predominantly with cryp- make antibody. tococcus and also candida, aspergilla, and histo- 5. Microglia : A unique CNS immune cell . plasma, are also seen. Direct injury to the nervous Microglia, which are pluripotent cells unique system from HIV occurs with HIV dementia (also to the CNS, make up approximately 10% of called AIDS–dementia complex or ADC), AIDS the glia in the CNS; their functions are poorly myelopathy, and HIV-associated neuropathy. understood. Immune stimuli result in at least These infections will be discussed in Chap. 12 . two changes in this CNS-resident cell popula- tion: activation and proliferation. They are cousins to monocytes and tissue macrophages, 5 The Necessity for Great Care and they cannot be readily distinguished in in Classifying a infl amed CNS from macrophages infi ltrating Neuroimmunological Disease from the blood. In addition to being able to as “Autoimmune” opsonize and process debris, they can also produce a number of cytokines, as well as Many neuroimmunological diseases have been serve as antigen-presenting cells. There is a classifi ed by some as “autoimmune” because evidence that they respond to signals from they are associated with lymphoid cell infi ltrates astrocytes and neurons. and because a pathogen is not an obvious cause 6. The HIV/AIDS revolution . The current prac- of the problem. This, of course, is inaccurate, and tice of neuroimmunology in the USA involves potentially dangerous. Most neuroimmunologi- two distinct populations of patients for which cal diseases are idiopathic, i.e., their etiology and different approaches must be taken: those who pathogenesis are unknown. Calling a disease are infected with HIV and those who are not. “autoimmune” indicates that the disease process The spectrum of diseases in each of these two is an attack by the immune system on an identi- groups is very different, so determination of fi ed nervous system antigen or combination of HIV status is important particularly in patients antigens. This concept has recently been summa- with neuroimmunological disease which is rized by Moses Rodriguez in an editorial in diffi cult to diagnose. Annals of Neurology manuscript titled “Have We At the end of 2006, over a million individuals Finally Identifi ed An Autoimmune Demyelinating in the USA were estimated to have HIV infection; Disease?” [1 3 ] ; he also summarized criteria for in more than a fi fth, the infection had not yet been an autoimmune disease (Table 2.2 ), and identi- diagnosed. HIV infection leads to defi cits in the fi ed how NMO meets most of these criteria. Even immune response, markedly increasing the prob- if an autoantibody can be identifi ed in a disease, ability of severe infections. Some of these infec- it is not necessarily indicative that the disease is tions, called opportunistic infections (OIs), are truly autoimmune, since autoantibodies can be found normally in a controlled, low-level state in induced by infections, e.g., a common immunocompetent individuals, but, because of autoantibody used in testing for syphilis is the anti- immunodefi ciency in the HIV-infected patient, cardiolipin autoantibody, i.e., the RPR or VDRL these pathogens proliferate, become uncontrolled, tests (see discussions of testing for syphilis in and cause injury or death. OIs are AIDS-defi ning Chaps. 12 and 18 ). No one would consider syphi- illnesses; i.e., prior to getting these illnesses the lis an autoimmune disease, but that is because the patient is considered as simply having HIV infec- pathogen of syphilis has been identifi ed. It is tion. The most prominent neurological infections likely that many of the diseases which some are 34 3 Neuroimmunology for the Non-neuroimmunologist Table 3.2 Criteria for autoimmunity (modifi ed from Rodriguez [1 3 ] ) Criteria Neuromyelitis optica Myasthenia gravis Multiple sclerosis Demonstration of an immune Yes. AQP4 (but not Yes. AChR or MUSK No response to a precise autoantigen all patients) in large percentage in all patients with the disease Reproduction of the lesion by Yes Yes No administration of autoantibody or T cells into a normal animal Induction of lesions by immunizing Not done Yes No an animal with relevant purifi ed autoantigen Isolation or presence of Yes. Anti-AQP4 Yes No autoantibody or autoreactive antibodies in the serum T cells from lesion or serum and pathological lesions Correlation of autoantibody Yes Yes. Prospectively, No or autoreactive T cell with within the same disease activity patient Presence of other autoimmune Yes Yes No. Slight increase in disorders or autoantigens autoimmune disease associated with disease prevalence compared to control population Immune absorption with purifi ed Not done Yes No autoantigen abrogates pathogenic autoantibody or autoreactive T cell Reduction of pathogenic autoantibody Yes. Plasma exchange Yes No or T cell associated with clinical improvement incorrectly identifying in the present as “autoim- mune” will in the future turn out to be infectious 6 The Importance of Antibodies in pathogenesis. The classifi cation of a disease as being auto- Antibodies, the product of B lymphocytes, are the immune has important diagnostic and therapeutic only molecules of the immune response that can ramifi cations. Thus, in diseases with likely auto- interact with high affi nity with a foreign molecule immune pathogenesis such as NMO and myas- in solution. They are the critical central molecule thenia gravis (MG), (Table 3 .2 ), the diagnosis in the humoral immune response. They have will be supported by demonstration of the auto- become highly important molecules to the neu- immune process, such as antibodies to aquaporin roimmunologist in many ways outlined below. In 4 or the nicotinic acetylcholine receptor (AChR). contrast, the T lymphocyte, the central cell of the In contrast, in diseases which are likely not auto- adaptive cellular immune response, has not been immune, an immune response to a neurological able to be utilized to a similar extent in the prac- antigen cannot be used to aid in diagnosis. In tice of clinical neuroimmunology. Despite its autoimmune diseases such as NMO and MG, clear importance in basic research on neuroimmu- immunosuppressive medications, some of which nological disease, measurement of T-cell function have substantial associated risks, might be used or use of T-cell-derived molecules has not signifi - aggressively, while in diseases likely not to be cantly entered clinical practice with the exception autoimmune, the extended use of potent immu- of measurement of T-cell subsets in patients sus- nosuppressives would be less likely to benefi t the pected of being infected with the HIV. patient. Similar care must be used when the words First, a brief clarifi cation regarding nomencla- “infl ammatory” or “immunologically mediated” ture: the words “immunoglobulins” and “antibod- are used, since these adjectives are often used ies” are generally used interchangeably. Frequently indiscriminately. “immunoglobulin” refers to molecules which have References 35 structures of immunoglobulin G, M, or the other have become an exponentially growing market. isotypes, but whose specifi city for any specifi c anti- Twenty-two monoclonals are now approved by gen is unknown. Conversely, “antibody” thus usu- the FDA for therapy and there are hundreds more ally is the word used for an immunoglobulin in clinical trials. One of the top selling and most molecule whose antigenic specifi city is known. As established monoclonal antibodies, approved by an example, in the anti-Semple vaccine immune the FDA in 1997, is rituximab, targeting CD20, response described earlier in the chapter, the anti- which is in clinical trials for therapy of MS. Semple vaccine antibodies produced in this response Natalizumab, rituximab, alemtuzumab, and are immunoglobulin molecules with high affi nities daclizumab are described in greater depth in for molecules present in the Semple vaccine. Chaps. 7 , 17 , and 19 . The importance of antibodies in neuroimmu- nology stems from their extensive use both diag- nostically and therapeutically. These are References summarized briefl y below: 1. Hemachudha T, Phanuphak P, Johnson RT, Griffi n DE, 1. Antibodies used for diagnostic purposes: Ratanavongsiri J, Siriprasomsup W. Neurologic com- (a) I nfections : For many infections, infection- plications of Semple-type rabies vaccine: clinical and induced antibodies assist in diagnosis of the immunologic studies. Neurology. 1987;37(4):550–6. infection. In fact, for infections in which the 2. Waksman BH. A history of neuroimmunology; a per- sonal perspective. In: Antel J, Birnbaum G, Hartung causative organism is diffi cult to grow in cul- HP, Vincent A, editors. Clinical neuroimmunology. 2nd ture or to amplify by PCR, anti-pathogen anti- ed. Oxford: Oxford

University Press; 2005. p. 425–45. bodies in the blood or CSF are almost the only 3. Hohlfeld R. Multiple sclerosis: human model for laboratory test which can assist the clinician. EAE? Eur J Immunol. 2009;39(8):2036–9. 4. Hatterer E, Davoust N, Didier-Bazes M, et al. How to Examples discussed in Chap. 12 are Lyme drain without lymphatics? Dendritic cells migrate disease, syphilis, and West Nile virus. from the cerebrospinal fl uid to the B-cell follicles of (b) Autoimmune diseases in which the molec- cervical lymph nodes. Blood. 2006;107(2):806–12. ular target is known : Myasthenia gravis or 5. Carson MJ, Doose JM, Melchior B, Schmid CD, Ploix CC. CNS immune privilege: hiding in plain sight. NMO, described in Chaps. 6 and 9 , is diseases Immunol Rev. 2006;213:48–65. in which the autoimmune process generates 6. Pachner AR. The immune response to infectious dis- antibodies to the anti-AChR or antibodies to eases of the central nervous system: a tenuous balance. aquaporin, which aid in diagnosis. Springer Semin Immunopathol. 1996;18(1):25–34. 7. Piyasirisilp S, Hemachudha T, Griffi n DE. B-cell (c) P araneoplastic autoantibodies : In these responses to myelin basic protein and its epitopes in diseases, described in Chap. 14 , which cannot autoimmune encephalomyelitis induced by Semple be characterized as autoimmune using standard rabies vaccine. J Neuroimmunol. 1999;98(2):96–104. criteria, antibodies reactive to identifi ed CNS 8. Meinl E, Krumbholz M, Hohlfeld R. B lineage cells in the infl ammatory central nervous system environment: proteins can be used as biomarkers of the dis- migration, maintenance, local antibody production, ease. An example is anti-Purkinje cell antibod- and therapeutic modulation. Ann Neurol. 2006;59(6): ies in paraneoplastic cerebellar degeneration. 880–92. (d) Therapy induced : Some forms of therapy 9. Westermann J, Pabst R. Distribution of lymphocyte subsets and natural killer cells in the human body. for neuroimmunological disease induce anti- Clin Investig. 1992;70(7):539–44. bodies to the therapy. Examples are anti-inter- 10. Knopf PM, Harling-Berg CJ, Cserr HF, et al. Antigen- feron-b or anti-natalizumab antibodies in dependent intrathecal antibody synthesis in the normal multiple sclerosis therapy. These therapies, rat brain: tissue entry and local retention of antigen- specifi c B cells. J Immunol. 1998;161(2):692–701. and their associated anti-therapy antibodies, 11. Hickey WF. Basic principles of immunological sur- are described in Chap. 7 . They often are called veillance of the normal central nervous system. Glia. neutralizing antibodies (NAbs), since they 2001;36(2):118–24. neutralize the therapeutic effect of the drug. 12. Harling-Berg CJ, Park TJ, Knopf PM. Role of the cervi- cal lymphatics in the Th2-type hierarchy of CNS immune 2. Therapeutic : regulation. J Neuroimmunol. 1999;101(2):111–27. Since 1986 when the fi rst one was approved by 13. Rodriguez M. Have we fi nally identifi ed an autoimmune the FDA, therapeutic monoclonal antibodies demyelinating disease? Ann Neurol. 2009;66(5):572–3. The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, 4 a Precis “ Can you do Addition? ”, the White Queen asked. “ What’s one and one and one and one and one and one and one and one and one and one? ” “ I don’t know ,” said Alice. “ I lost count .” Lewis Carroll, T hrough the Looking Glass 1 Defi nition 2 Etiopathogenesis Multiple sclerosis (MS) is a disease of the central The etiology and pathogenesis of MS are nervous system primarily affecting young adults, unknown. Many investigators through the decades usually characterized by the development of sud- have been very convinced that their particular den exacerbations (attacks) with remissions of hypothesis is correct, but the etiology remains focal neurological dysfunction and the develop- enigmatic. There is some genetic proclivity since ment of progressive neurological disability over family members of MS patients have higher inci- time. Lesions in the CNS are continually accrued dences of MS relative to the general population. (“one and one and one…”) so that over time, the These aspects will be described in greater detail CNS is damaged as a function of the frequency in the section on genetics and epidemiology of and location of lesions balanced by as yet poorly MS (below). understood reparative processes. It is character- The history of “changing paradigm shifts” in ized pathologically by infl ammation and demyeli- MS pathogenesis has been well-summarized by nation as well as remyelination exclusively in the Byron Waksman [ 1 ] . In the nineteenth century, central nervous system, with no pathology in the during the fi rst years of neurology as a fi eld of peripheral nervous system or non-nervous system medicine, “disseminated sclerosis” was thought tissue. Its cause is unknown and its treatment is to be due to glial scarring. Later, MS was thought currently suboptimal in that exacerbations and possibly to be a thromboembolic phenomenon. disease progression are not universally halted. It In the early years of the twentieth century, MS is a uniquely human condition and although there was considered as a problem of myelin break- are animal models, none is fully faithful to the down, and later in the twentieth century, measles human disease. In some patients with MS, those virus was an attractive causative agent. It was not with the primary progressive form of the disease, until immunology emerged as a major fi eld of there is simply progression of disability without scientifi c endeavor in the latter third of the twen- exacerbations or remissions. tieth century that neurologists became interested A.R. Pachner, A Primer of Neuroimmunological Disease, 37 DOI 10.1007/978-1-4614-2188-7_4, © Springer Science+Business Media, LLC 2012 38 4 The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, a Precis in autoimmunity as a possible cause. Waksman effect on certain aspects of the disease. On the stressed that the increased interest in a possible possible pathogen side are many arguments immune pathogenesis went hand-in-glove with against T-cell mediation such as the absence of advances in immunology, arguably the most rap- the effect of the anti-T-cell drug cyclosporine idly moving fi eld in medicine over the last 50 years. [ 2 ] , the failure to demonstrate signifi cant auto- One of the reasons that paradigm shifts have immune T-cell activity in MS patients, and the occurred and likely will continue to occur is that, fact that several viruses reproduce the features although each postulated pathogenesis has sounded of MS when injected into experimental animals exciting and interesting, none of them has yet fully (see Sect. 1 of Chap. 8 ). fi t the experimental data or been able to predict These arguments have more than just aca- responses to therapies. The fullness of time will demic repercussions. For many “T-cell autoim- tell whether the autoimmunity hypothesis has a munity” proponents, therapy of MS requires more lasting tenure than did glial scarring, throm- aggressive immunosuppression using medica- boemboli, myelin breakdown, or measles virus. tions or interventions that carry signifi cant risks Currently, the most prominent hypotheses remain and have unproven effi cacy over an extended autoimmunity and chronic infection, theories period of time. Those who do not believe in the which are not mutually exclusive. “T-cell autoimmunity” hypothesis favor using Another important summary of the many safer medications and supporting research into hypotheses that have come and gone can be found nonimmune aspects of the disease to identify in Murray’s excellent book, Multiple Sclerosis: nonimmune targets for therapy. The situation is The History of a Disease , especially Chapter 11, made more complex by the fact that the number “Searching for a Cause of MS.” These very well- of relapses does not correlate well with progres- written 90 pages provide the reader with a good sive disability (see Chap. 6 ), indicating that the understanding of the search for an infectious, primary measure which the FDA uses to judge genetic, epidemiological, immunological, vascu- therapies, i.e., relapse rate, may be irrelevant for lar, or environmental cause. the aspect of the disease that is most damaging, C urrently, there are camps representing some i.e., disability progression. Unfortunately, given of the leading hypotheses for pathogenesis of these current complexities of the disease and its MS. The largest camp consists of those scientists treatment, the lack of well-run long-term studies and clinicians who are convinced that the prob- of the various agents, and controversy about the lem is “autoreactive T cells,” thus an autoimmune etiopathogenesis of the disease, the use of most disease. This group is opposed by an equally of these medications over the long term to sub- impressive group who feels that the “autoreactive stantially improve the natural history of the dis- T cell” hypothesis remains just that: a hypothesis ease relative to disability remains more which is largely unproven despite the expendi- “faith-based” rather than “evidence-based.” ture of a great amount of funding, time, and effort in that direction, and that the cause of the disease lies elsewhere, such as an infectious pathogen or 3 Pathology a neurodegenerative process. T here are cogent arguments on both sides, The pathology of multiple sclerosis is both distinc- very briefl y reviewed below. Supporting the tive and unique. The most obvious pathology, eas- “T-cell autoimmune” hypothesis are animal ily seen in gross as well as microscopic specimens, experiments in which, autoreactive T cells can is the MS plaque, representing well-circumscribed cause infl ammation in the brain, and the pathol- loss of myelin (see Chap. 2 ). Late nineteenth cen- ogy shows T cells within lesions. Therapies tury neurologists, especially Charcot and others at which affect the immune response, such as cor- the Saltpetrière, included autopsy in their reper- ticosteroids, IFN - b , and natalizumab (a human- toire of learning about the nervous system. They ized anti-integrin antibody) have an ameliorative commented on the feel of the areas in which 5 Clinical Manifestations 39 myelin was lost, the fi rmness of the tissue in north or south from the equator. There is no contrast to the soft normally myelinated tissue accepted explanation for this. However, some around the plaque. This prompted the name in recent studies from Latin America do not support French, “sclérose en plaques disseminée,” and in this gradient of MS prevalence. France today, the term “sclérose en plaques” (SP) Individuals with MS in the family are more likely is still used. “Multiple sclerosis” became the term to develop the disease than individuals who lack this which achieved fairly broad international accep- family history, and the likelihood increases the closer tance for the condition in the 1950s, especially after the genetic relationship to the proband. Ebers [8 ] has the publication in 1955 of McAlpine’s classic text summarized the data recently in an excellent review. on the disease bearing that name as its title [3 ] . In a population in which the prevalence of MS is In early MS, there is prominent perivenular 1/1,000, relatives have prevalences as follows: infl ammation and little, if any, atrophy. As the dis- adoptive siblings—1/1,000, fi rst cousin—7/1,000, ease progresses, there are more and more “sharp- full sibling—35/1,000, and monozygotic twin— edged plaques” [ 4 ] , areas of near complete loss of 270/1,000. That no single gene is highly correlated myelin with a sharp border surrounded by normally with the disease indicates the polygenic basis for myelinated tissue. Areas of atrophy, initially small, MS. The nearest is the link to the major histocom- become confl uent and there are increased numbers patibility complex (MHC), especially to class II of demyelinated plaques, which also become con- MHC. However, associations with the MHC are fl uent. Infl ammatory cells, including plasma cells, complex, and the associations are not as straightfor- become more prominent within the parenchyma. ward as previously thought [9 ] . Sharp-edged plaques had for years been thought to be unique for MS, but have relatively recently been described in a variation of the EAE model in the 5 Clinical Manifestations marmoset [5 ] , using a protocol of immunization with human white matter (see Chap. 8 ). 5.1 Initial Symptoms T he pathology of MS prior to 1996 was felt to be relatively homogeneous. Then, in 1996 Many of the fi rst symptoms of MS are so mini- Lucchinetti et al. postulated four different forms mal and fl eeting that they are ignored. There may of MS lesions, with only one of the forms occur- be some numbness or tingling in an arm or leg ring in any one patient, which they felt had patho- for a few days with resolution, followed

by genetic signifi cance [6 ] and signifi ed “different months or years of normal neurological health. immunological mechanisms of myelin destruc- Then a few weeks of problems with balance tion in MS.” The subsequent years have seen con- attributed to a “virus” may occur, again with siderable resistance to this classifi cation, and a resolution, followed by no symptoms for years. recent paper identifi es “a uniform pre-phagocytic Finally, blindness in one eye prompts an investi- pathology and overlap of lesion subtypes in indi- gation leading to the correct diagnosis. In the vidual patients with typical relapsing and remit- majority of patients with MS, at their fi rst diag- ting disease” [7 ] . It remains controversial whether nosis there is clinical and MRI evidence, sug- there are substantially different pathologies or gesting that the disease had been present years even different biologies of MS. prior to their diagnosis. Multiple sclerosis means “many plaques,” and the lesions, and thus clinical symptoms, can be 4 Genetics and Epidemiology anywhere there is CNS myelin. CNS myelin is present in all white matter in the CNS, and areas The prevalence of MS is highly variable depend- which are particularly frequently targeted are ing on geographic region. It has long been thought periventricular areas, optic nerves, cerebellar and that countries near the equator have a low preva- pontine white matter, and white matter tracts in lence, with increasing prevalence moving either the cervical and thoracic spinal cords. Little is 40 4 The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, a Precis Fig. 4.1 Internuclear ophthalmoplegia (INO): This patient is being asked to look to his right. His right eye is able to do that but not his left. A similar problem occurs when asked to look to his left known of the factors which determine whether a neurologists become particularly concerned given white matter lesion will result in any clini- about the possibility of MS. One of these is cal sequelae. In a recent MS study using monthly involvement of the medial longitudinal fasciculus MRI scans with high sensitivity for new MS (MLF), a white matter tract in the midbrain which lesions [1 0 ] , for every new MRI lesion leading to provides for proper communication between the symptoms, there were 17 new MS lesions that did nuclei controlling eye movements so that conju- not result in any clinical symptoms, a number gate eye movement can be performed. Lesions in consistent with other studies in the literature. the MLF cause a particular form of “eye weak- ness” (ophthalmoplegia), called “internuclear.” Internuclear ophthalmoplegia (INO) results in 5.2 The MS Attack symptoms of double vision, especially when looking to the side (Fig. 4 .1 ). Another common … this girl’s clinical picture can NOT be produced initial manifestation is acute infl ammation of the by one lesion. It is like the mathematics lesson in optic nerve (optic neuritis), which results in eye Through the Looking Glass , a process of addition. No one sign constitutes the diagnosis; it is the sum pain and loss of visual acuity, sometimes so of many over the years. There is manifest evidence severe as to cause complete blindness in that eye. of damage to the cerebrospinal motor pathways. If There is no universally accepted defi nition of a preparation of the brain and spinal cord were an attack. For clinical trials in which the primary nailed to a barn door and shot at with a spread of No.6 shot, the pyramidal tracts could not in all endpoint is number of attacks, a rigorous defi ni- verity escape. And seldom are there lacking signs tion of an attack is needed, but they are defi ned of such involvement in this disease. It consists of differently in different trials. Most clinical trials multiple, disseminated plaques of hardening in the will require a neurologist-documented worsening spinal cord. in the patient’s neurological function, often linked H arry Lee Parker, M.D., “Multiple sclerosis” in to the EDSS (Expanded Disability Status Scale), Clinical Studies in Neurology sometimes called the Kurtzke score, a standard The archetypal presentation of MS is an disability measure (see below). As the defi nition “attack” or “relapse.” There is the rapid develop- of relapse has become more important in the ment over hours to a few days of a neurological development of new drugs for MS, defi nitions defi cit referable to injury to some area within the have become more complex. An example of a CNS. An arm may go numb, double vision defi nition of an “attack” or “relapse” can be found develop, one side of the face droop, or a leg in a recent head-to-head study of two MS treat- become weak. The problem lasts for a few days ments, the BECOME study, which utilized two to a few weeks and then slowly gets better and different MS rating scales and distinguished frequently completely resolves, even without between a subjective and an objective relapse therapy. Some syndromes are so characteristic [ 10 ] : “All new or worsening neurologic symp- that when they fi rst appear in a young patient toms lasting greater than 24 h and not explained 5 Clinical Manifestations 41 by fever or infection were considered subjective measure axonal injury on MRI. In fact, there is relapses. Subjective relapses that were confi rmed no accepted measure of axonal injury on MRI, by a blinded examining neurologist using wors- although a number of excellent investigators are ening scores on either the Scripps Neurological working on this problem. Second, the pathologic Rating Scale or the EDSS were considered objec- hallmark of MS has always been demyelination tive relapses. One or more of the following because myelin is easy to stain, and the dramatic changes compared with baseline was required for loss of myelin is so obvious on pathology. A sim- relapse confi rmation: (1) increase in total EDSS ilarly obvious measure does not exist for axonal by greater than or equal to 0.5 point; (2) increase injury. When axonal injury has been studied, it in the EDSS score for one system greater than or appears to be a critical component of CNS injury equal to 2 points; (3) increase in the score of 2 or in MS [ 11 ] . more EDSS systems greater or equal to 1 point; It is the combination of accrual over time of and (4) decrease in SNRS score by greater or both axonal injury and demyelination with inad- equal to 7 points.” However, in routine neurologi- equate recovery that ultimately leads to the devel- cal practice neurologists usually will use their opment of disability. Disability in MS can be clinical experience to identify an attack. When measured in a number of ways, but the most com- specifi cally asked to defi ne an attack, they might monly used measure in clinical trials is the EDSS say, “I know one when I see it,” and they are usu- [ 12 ] (Table 4 .1 ). This scale involves the measure- ally proven correct by the subsequent course of ment of the amount of functional limitations in a the patient. number of neurological functions, which are fac- After a fi rst attack the patient is considered to tored in and collated to provide a single number. have a “clinically isolated syndrome” (CIS) A score of zero indicates no disability and a score which may not end up being MS. Thus, a sub- of ten is death from MS; a score of six is given to stantial percentage of patients with optic neuritis an MS patient who requires an aid to ambulate. do not develop MS. Depending on the study, that When patients see their physicians and when number is 20–50%. The probability of develop- physicians weigh the effi cacy of therapy, it is the ing “clinically defi nite MS” (CDMS) over time is rapidity of disability progression that is upper- substantially increased in CIS patients if they most in their minds. The rapidity of accrual of have MRI abnormalities consistent with MS out- disability over time is highly variable and is a side of the areas in the CNS associated with their feature of MS which can be called MS severity. symptoms. Thus, a young otherwise healthy MS severity can be measured with the MS patient with optic neuritis is much more likely to Severity Score (MSSS) [1 3 ] . For instance, a develop MS if she is found to have periventricu- patient with relatively mild disability, an EDSS lar white matter lesions on brain MRI than if no of 3, would have a very low MSSS, if she has had lesions are evident. This will be discussed at the disease for 30 years. In contrast, a different greater length in the next chapter. patient with the same EDSS developed over A s the disease continues and there is more 2 years will have a high severity score, since a involvement of the white matter, there is also substantial amount of disability was accrued over axonal injury. Axonal injury has received much a very short period of time. less attention than has demyelination for two This accrual of neurological disability over reasons. First, the usual tool clinicians use to time does not correlate with many other features measure damage to CNS structure is magnetic of the disease. For instance, the number or sever- resonance imaging. Because water constitutes a ity of clinical attacks or the degree of CNS demy- low percentage in CNS myelin and increases elination by MRI does not correlate very well when that myelin is lost, the gain in the water sig- with neurological disability. Since we have nal is a very strong marker of demyelination. learned from MRI studies that there are many There is no equivalently straightforward way to new MRI lesions for each new clinical attack, it is 42 4 The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, a Precis Table 4.1 EDSS (also called Kurtzke score) 0 Normal neurologic exam 1.0 No disability, minimal signs in one functional system 1.5 No disability, minimal signs in more than one functional system 2.0 Minimal disability in one functional system 2.5 Minimal disability in two functional systems 3.0 Moderate disability in one FS, or mild disability in three or four functional systems though fully ambulatory 3.5 Fully ambulatory but with moderate disability in three or four functional systems 4.0 Fully ambulatory without aid, self-suffi cient, up and about some 12 h a day despite relatively severe disability. Able to walk without aid or rest some 500 m 4.5 Fully ambulatory without aid, up and about much of the day, able to work a full day, ma otherwise have some limitation of full activity or require minimal assistance, characterized by relatively severe disability. Able to walk without air or rest for some 300 m 5.0 Ambulatory without aid or rest for about 200 m; disability severe enough to preclude full daily activities (e.g., to work full day without special provisions) 5.5 Ambulatory without air or rest for about 100 m; disability severe enough to preclude full daily activities 6.0 Intermittent or unilateral constant assistance (cane, crutch, or brace) required to walk about 100 m with or without resting 6.5 Constant bilateral assistance (canes, crutches, or braces) required to walk about 20 m without resting 7.0 Unable to walk beyond about 5 m even with aid. Essentially restricted to a wheelchair. Wheels self in standard wheelchair and transfers alone. Active in wheelchair about 12 h a day 7.5 Unable to take more than a few steps. Restricted to wheelchair. May need air to transfer. Wheels self but cannot carry on in standard wheelchair a full day, May require a motorized wheelchair 8.0 Unable to walk at all, essentially restricted to bed, chair, or wheelchair but may be out of bed much of the day. Retains many self-care functions. Generally has effective use of the arms 8.5 Essentially restricted to bed much of the day. Has some effective use of arm(s). Retains some self-care functions 9.0 Helpless bed patient. Can communicate and eat 9.5 Totally helpless bed patient. Unable to communicate effectively or eat/swallow 10 Death due to multiple sclerosis Source : Kurtzke [1 2 ] not surprising that the clinical attacks would not FDA approval, of new treatments

for MS, which predict clinical disability very well, since the vast is a problem since relapse frequency does not majority of MS-induced injuries to the CNS are correlate with disability progression (see Chap. 7 ). subclinical. This has led to recommendations for the more frequent use of MRI outcomes for studies rather than using attack rate [1 4 ] . 6 Natural History and Prognosis However, MRIs do best when CNS demyelina- tion is being measured and even the extent of The natural history of MS has been well docu- CNS demyelination does not correlate well with mented for populations. For most patients, those clinical disability. Clinical disability may be with relapsing–remitting MS (RRMS), there are determined to a large extent by axonal injury, at least fi ve stages (Table 4.2 ): the fi rst is a “pre- which is very diffi cult to measure by MRI. There clinical stage” in which white matter lesions is some evidence that disability correlates well detectable on MRI accumulate, but there are no with the development of spinal cord atrophy [1 5 ] . symptoms identifi ed by the patient. The second In the USA, pharmaceutical companies have used stage begins with the fi rst development of clinical relapse data rather than disability data to obtain symptoms, usually an attack, which prompts the 7 MS Clinical Classifi cations 43 Table 4.2 The fi ve temporal stages of MS provide the MS patient with a prognosis, and very Preclinical few neurologists will attempt to predict the course First attack—clinically isolated syndrome (CIS) of any particular patient. Relapsing-remitting MS Secondary progressive MS Late MS 7 MS Clinical Classifi cations Given the complexities of MS, with its unknown diagnosis of CIS. At some point, months or years etiology and unpredictable course, there have later, further clinical or MRI lesions develop, been many attempts at classifi cation to provide resulting in the diagnosis of MS, and the begin- some framework for understanding the disease ning of the third stage, that of RRMS. In most (Inset 4 .1 ). MS patients, these attacks occur periodically, but early on, disability is not a dominant factor. At some point, relapses become less common and Inset 4.1 Two Clinical Vignettes of Patients disability is more prominent and progressive. with MS This stage is called secondary progressive MS Patient #1 . Mother of three with confusion (SPMS). In many patients, there is subsequently and trouble walking a fi fth stage, in which disability plateaus and pro- ST was a 27-year-old mother of three when gression ceases. This temporal classifi cation she was seen at University Hospital for a applies to patients diagnosed with RRMS. second opinion. A substantial portion of MS patients never She was completely well until 5 months have a true attack and simply have progressive prior to her visit. At that time, she devel- disability over time, a condition called primary oped visual problems and gait unsteadi- progressive MS (PPMS). Many patients have ness. An evaluation at that time was something in between, i.e., just one or two clini- consistent with MS. This seemed to cal attacks over time, followed by progressive improve but very shortly thereafter she disability; these patients will usually be classifi ed worsened and began to have personality as having RRMS. changes, increasing problems with gait, As well as this natural history applies to popu- weight loss, worsening speech problems. lations, it applies poorly to the individual MS She was begun on interferon-b but contin- patient. When I see an early MS patient, I stress ued to have worsening. that each individual has his or her own form of MRI scans of the brain over the past MS: that Ms. X has the Ms. X form of MS, a very months prior to the fi rst visit revealed mul- different form than Mr. Y or Mrs. Z. Suffi ce it to tiple enhancing lesions distributed through- say that the vast majority of MS patients fi rst see out her brain. a neurologist when they are young, and 20 years Examination of her fi rst visit to later, by the time they are middle-aged, many University Hospital revealed a thin young have accrued a substantial amount of neurologi- woman in no acute distress. On mental sta- cal disability. Not only is the disease variable tus examination she was disoriented to time from patient to patient, but it is also variable (November 1994—didn’t know day), but within any particular patient. Ms. X can have a oriented to place and person. She was fl urry of activity in her early 30s, i.e., multiple barely able to repeat 3/3 objects, and her attacks and the development of disability, and recall after 1 min was 0/3. Serial 3 s was then again in her late 40s, with 15 intervening performed down to 97, but no further. She years of no clinical or MRI activity. The highly knew the names of the President the Vice unpredictable nature of the disease creates great President. diffi culty for any clinician who attempts to (continued) 44 4 The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, a Precis Inset 4.1 (continued) brain revealed multiple white matter lesions, Cranial nerve examination revealed that of which two were enhancing. The patient there was fi ne nystagmus bilaterally on refused medication and has been followed lateral gaze. Cranial nerves were normal clinically and radiologically over the last except that she had grossly dysarthric 6 years and continues to have no new neu- speech. She had mild dysmetria on fi nger rological symptoms and no neurological to nose, and diffuse weakness in all extrem- disability. One MRI scan in the interval ities (4/5). Her DTRs were 3 to 4+ through- between 2004 and 2010 showed two out and there was ankle clonus bilaterally. enhancing lesions but this was not associ- Her gait was markedly ataxic, and tandem ated with symptoms. She has continued to gait could not be performed. not wish any medication for her MS. MRI of the brain revealed multiple white Author’s note . These two patients, both matter lesions, many of which enhanced with the diagnosis of MS, have very differ- with gadolinium. ent histories. In the fi rst patient her MS was Because of the aggressive nature of her devastating and led to a marked permanent MS, she was admitted to University Hospital and progressive worsening of her quality of for intravenous immunosuppressives. Over life. In the second patient her MS, although time she improved with continued treat- quite active early in her disease, was only a ment, but remained unable to walk a straight minor problem for more than 20 years, and line, continued to have memory and person- she remains without any disability after ality defi cits, and was unable to care for her 26 years of the disease. children or hold a job without assistance. Patient #2. Salesperson with occasional problems with walking MC was a 42-year-old salesperson for a 7.1 “Form of MS” chemical company with known MS who came to the MS center for the fi rst time in In the early twentieth century, MS was classifi ed 2004 with dizziness. by the location of the major involvement: brain She was well until 1984 when she lived stem or spinal cord forms. For several decades, in another state and developed left hemipa- neurologists have classifi ed MS according to the resis and was diagnosed as having MS. She occurrence of relapses, as described above. Thus, had a number of attacks in the fi rst 3 years the most common form of MS is RRMS. Since after diagnosis, including partial blindness the effi cacy of current therapies are predomi- in one eye, bilateral leg weakness tran- nantly in decreasing relapses, PPMS patients siently requiring a cane, and a hemisensory have not been entered into most recent studies, syndrome. Each of these attacks resolved and the indications for commonly used therapies, within a few weeks without residua. From do not include patients with PPMS. 1987 to 2004, she had had no attacks and Some neurologists use the term SPMS to had no symptoms of her MS. classify patients with MS later in the disease She developed “dizziness” about 2 weeks when relapses usually begin to be less frequent, prior to her 2004 MS center visit, consisting but disability progression continues. The term is of some light-headedness and diffi culty with misleading because there is almost always pro- walking. This resolved after a few days. gression in the CNS damage in the disease, even Her neurological examination in 2004 in early stages of the disease. Also, the term “sec- was completely normal, but MRI of the ondary” implies that the disability is secondary to the relapses early in the disease and there is 7 MS Clinical Classifi cations 45 Fig. 4.2 MRI of the brain: Serial images over time with typical relapsing form of MS and progressive disability. new lesions appearing and disappearing. Serial gadolin- Note the new lesions that appear during this 3-year ium-enhanced T1-weighted (u pper row ) and FLAIR follow-up, some of them showing gadolinium enhance- (l ower row ) MRI images of the brain in a patient with a ment ( arrows ) substantial evidence that this link, i.e., of disability Although this measure of disability is not as with relapses, does not indeed exist. broadly used as the EDSS, and is relatively new, it has signifi cant advantages, including testing of cognitive function, a frequent but underassessed 7.2 Disability problem in MS, and the ability to be used by health care professions other than neurologists. Neurologists also classify patients by disability. The most commonly used disability scale is the EDSS described above, also called the “Kurtzke 7.3 Activity scale” after its originator, John Kurtzke. On this scale, the degree of abnormality of a variety of Sometimes MS is classifi ed according to its activ- functions, quantitated on “functional scales,” are ity as measured by attack frequency or number of combined with measures of gait. On this scale, 0 acute lesions on MRI. Many of the drugs cur- is normal, i.e., no disability, and 10 is death from rently used in MS are thought to function by severe MS. decreasing the activity of the disease. The attack A nother recently developed disability scale is frequency correlates fairly well with MRI activ- the “multiple sclerosis functional composite ity, so that patients with multiple gadolinium- score” (MSFC). The three components of this enhancing lesions at any point in time tend to scale are the 9-hole peg test, which measures have frequent attacks; gadolinium is a compound hand strength and dexterity; 25 foot timed walk, frequently injected intravenously during MRI a gait measure; and the paced auditory serial scans to detect active MS lesions and is described addition test (PASAT), a test of cognitive function. in Chap. 5 (Fig. 4 .2 ). This has led some MS 46 4 The Prototypic Neuroimmunological CNS Disease: Multiple Sclerosis, a Precis investigators to propose MRI as the primary advocate MRI measures to quantitate the disease. endpoint measure for clinical trials [1 4 ] , while Pathologists study the extensive tissue injury in others consider this to be a poor idea [1 6 ] . the CNS, but argue about whether there are dif- ferent forms of pathology, or a unitary process. The situation is similar to the Indian story of the 7.4 Severity elephant and the blind men who say the elephant is a rope, a pipe, a hand fan, a branch, a pillar, or Although relapses are disturbing, most MS a wall depending on what part of the animal they patients and neurologists would use progression are feeling at the time. These multi-faceted of disability as their main determinant for sever- aspects of MS are especially relevant to the issue ity. That is, they would classify a patient’s MS as of therapy (see Chap. 6 ). being severe if disability is being rapidly accrued. In 2005, a large group of European neurologists published results of a study of 9,892 patients References which classifi ed their MS by rapidity of accrual of disability on a decile scale, where 1 (e.g., pro- 1. Waksman BH. Demyelinating disease: evolution of a gression to an EDSS of 2 after 19 years of the paradigm. Neurochem Res. 1999;24(4):491–5.

2. Effi cacy and toxicity of cyclosporine in chronic pro- disease) was very mild MS and 9 very severe MS gressive multiple sclerosis: a randomized, double- (e.g., progression to an EDSS of 6, i.e., needed an blinded, placebo-controlled clinical trial. The Multiple aid to ambulate, after only 4 years of disease). Sclerosis Study Group. Ann Neurol. 1990;27(6): The ideal therapy should ameliorate the severity 591–605. 3. McAlpine D, Compston ND, Lumsden CE. Multiple of a patient’s MS over the long term, but no cur- sclerosis. Edinburgh: E & S Livingston; 1955. rently available therapy has been shown to do 4. Poser CM, Brinar VV. Diagnostic criteria for multiple that [ 17 ] . Increasingly, investigators are using sclerosis: an historical review. Clin Neurol Neurosurg. this MSSS in clinical research in MS. 2004;106(3):147–58. 5. Massacesi L, Genain CP, Lee-Parritz D, Letvin NL, M ultiple sclerosis and t he Blind Men and the Canfi eld D, Hauser SL. Active and passively induced Elephant : MS remains a mysterious disease, experimental autoimmune encephalomyelitis in com- which changes the lives of the patients who have mon marmosets: a new model for multiple sclerosis. it and the physicians who care for these patients. Ann Neurol. 1995;37(4):519–30. 6. Lucchinetti CF, Bruck W, Rodriguez M, Lassmann H. Because of our lack of knowledge about the etiol- Distinct patterns of multiple sclerosis pathology indi- ogy, pathogenesis, proper therapy, and our inabil- cates heterogeneity on pathogenesis. Brain Pathol. ity to predict the future course of any MS patient, 1996;6(3):259–74. each individual will see the disease and attempt 7. Barnett MH, Parratt JD, Pollard JD, Prineas JW. MS: is it one disease? Int MS J. 2009;16(2):57–65. to assess the same disease in different ways. The 8. Ebers GC. Environmental factors and multiple sclero- patient may be particularly concerned about her sis. Lancet Neurol. 2008;7(3):268–77. present disability, trying to maximize day-to-day 9. Ramagopalan SV, Knight JC, Ebers GC. Multiple quality of life and mobility. The patient’s family sclerosis and the major histocompatibility complex. Curr Opin Neurol. 2009;22(3):219–25. may be focused on the severity, seeing the accrual 10. Cadavid D, Wolansky LJ, Skurnick J, et al. Effi cacy of of disability, and comparing what their loved one treatment of MS with IFN{beta}-1b or glatiramer can do now compared to what they did a year or acetate by monthly brain MRI in the BECOME study. two before. Pharmaceutical companies and drug Neurology. 2009;72:1976–83. 11. Trapp BD, Nave KA. Multiple sclerosis: an immune regulatory agencies focus on the attacks since or neurodegenerative disorder? Annu Rev Neurosci. currently therapies are approved or denied based 2008;31:247–69. on their ability to decrease attack frequency. 12. Kurtzke JF. Rating neurologic impairment in multiple Radiologists evaluate the extensive demyelina- sclerosis: an expanded disability status scale (EDSS). Neurology. 1983;33(11):1444–52. tion, try to develop techniques to measure neu- 13. Roxburgh RH, Seaman SR, Masterman T, et al. ronal pathology and atrophy in the disease, and Multiple Sclerosis Severity Score: using disability References 47 and disease duration to rate disease severity. progressive multiple sclerosis. Mult Scler. 2008; Neurology. 2005;64(7):1144–51. 14(8):1068–75. 14. Lincoln JA, Cadavid D, Pollard J, et al. We should use 16. Daumer M, Neuhaus A, Morrissey S, Hintzen R, magnetic resonance imaging to classify and monitor Ebers GC. MRI as an outcome in multiple sclerosis the course of multiple sclerosis. Arch Neurol. clinical trials. Neurology. 2009;72(8):705–11. 2009;66(3):412–4. 17. Daumer M, Neuhaus A, Herbert J, Ebers G. Prognosis 15. Furby J, Hayton T, Anderson V, et al. Magnetic reso- of the individual course of disease: the elements of nance imaging measures of brain and spinal cord atro- time, heterogeneity and precision. J Neurol Sci. phy correlate with clinical impairment in secondary 2009;287 Suppl 1:S50–5. Multiple Sclerosis: Diagnosis 5 In the usual forms of multiple sclerosis, i.e. in those with a relapsing and remitting course and evidence of disseminated lesions in the CNS, the diagnosis of multiple sclerosis is rarely in doubt. Raymond D. Adams and Maurice Victor, Principles of Neurology There is no specifi c diagnostic test for MS. The presentation to the neurologist, most patients diagnosis is usually made on the basis of a char- with MS declare themselves with evidence of acteristic constellation of symptoms, signs, and new disease activity consistent with the diagno- laboratory fi ndings. There are no diagnostic crite- sis, and what might have been an 85 or 95% prob- ria that are both universally accepted and that ability of the diagnosis at the fi rst evaluation, neurologists invariably utilize in their day-to-day increases to 99% or higher. practice. Given the complexity of the central ner- As noted in the previous chapter, the histo- vous system, it is not surprising that many prob- pathologic hallmark of MS is a combination of lems arise when the MS patient presents with infl ammation, demyelination, and axonal injury symptoms early in the course of the disease. limited to the CNS in the absence of any possible There are frequent false-positive and false- alternative diagnosis. Substantial CNS activity negative fi ndings, even by neurologists experi- early in MS usually does not translate into severe enced in MS. The diffi culties in diagnosis lead to symptoms. Patients with MS early in their dis- anxiety among patients and their families during ease prior to seeing a neurologist frequently have the evaluation period. The careful neurologist symptoms that appear and then disappear after always makes the diagnosis of MS provisionally days to weeks. These symptoms can be nonspe- even in apparently obvious cases, assessing the cifi c and are frequently not helpful in differentiat- odds over time, with the probability of MS always ing MS from other diseases. Some symptoms are being less than 100%. Complete certainty is nei- very common, such as decreased visual acuity, ther possible nor necessary to make the diagnosis double vision, numbness and tingling, and prob- of “defi nite MS.” lems with balance; others such as problems with If MS is so diffi cult to diagnose in its early hearing are less common. stages, how can Adams and Victor write, “the Ultimately, a major symptom develops, which diagnosis is rarely in doubt?” It is because the may or may not be more severe than previous diagnosis becomes clearer and clearer over episodes, but brings the MS patient to a physi- the course of time. Within the fi rst few years of cian. In the absence of any other obvious disease A.R. Pachner, A Primer of Neuroimmunological Disease, 49 DOI 10.1007/978-1-4614-2188-7_5, © Springer Science+Business Media, LLC 2012 50 5 Multiple Sclerosis: Diagnosis process, when early MS is suspected, the fi rst episode, the fi rst highly symptomatic relapse or 1 History and Examination attack, is also labeled “clinically isolated syn- drome (CIS),” because it is clinically isolated in MS almost always has its onset in young people time. Many patients have no history of previous 20–35 years old. The mean age of patients entered symptoms and their CIS is their fi rst manifesta- into studies of multiple sclerosis is usually in the tion of neurological disease. Other patients have early to mid-30s. Preadolescent or middle-aged had vague, transient symptoms for which they individuals are less likely to develop the disease did not seek medical attention. For yet others, than people in their 20s and 30s. Although more some symptoms had occurred in the past, but had women have MS than men, the 2:1 ratio is not been not been attributed to MS, and the symp- particularly helpful diagnostically. Even though toms had resolved. It is at this point that the neu- most patients do not have a blood relative with rologist is faced with the challenge of making a MS, a positive family history increases the likeli- diagnosis of CIS versus some other neurological hood of MS. disease process. A careful history and thorough general and I t must be stressed that CIS is a diagnosis that neurological examination are critical for the patient prejudices physicians toward MS and is consid- with a possible diagnosis of CIS to identify condi- ered by most neurologists to be a “pre-MS” con- tions causing disease outside of the CNS, and thus dition. The diagnosis of CIS thus should only be to “rule out” CIS, and to identify fi ndings on neu- made in the absence of an alternative diagnosis. rological examination consistent with CNS injury, Although CIS or MS can certainly coexist with i.e., to “rule in” CIS. A history consistent with any other diseases, most neurologists will use of the possible “MS mimickers” (Chap. 6 ) or “Ockham’s razor” (see Inset 5 .1 ) in their approach underlying medical conditions that predispose to to a relatively uncomplicated new patient, and cerebrovascular disease, such as hypertension, will want to make a single diagnosis. Similar to diabetes, smoking, contraceptive use, or positive MS being a less than 100% certain diagnosis, the family history needs to be sought. Risk factors for diagnosis of CIS must always be made with HIV infection, such as intravenous drug abuse, the continued realization that other diagnoses promiscuous sexual practices, or HIV in a sexual remain possible. partner need to be ascertained. Other medical con- ditions which can lead to neurological symptoms such as systemic lupus erythematosus (SLE) need to be considered. In areas endemic for Lyme Inset 5.1 Ockham’s Razor disease, a history of an unusual skin rash, facial paralysis, or chronic headache syndrome raises the In Latin, this maxim is p luralitas non est possibility of B orrelia burgdorferi infection. ponenda sine necessitate or “plurality Enlarged lymph nodes raise the possibility of should not be posited without necessity.” lymphoma or sarcoidosis. Attributed to the fourteenth century Most patients with CIS will have an abnor- Franciscan friar and logician, William of mality on neurological examination consistent Ockham, the application to medicine is that with their symptoms. Thus, patients complaining of “diagnostic parsimony,” i.e., that a doc- of decreased vision who have optic neuritis will tor should try to look for the fewest possi- have decreased visual acuity in the affected eye ble causes, preferably just one, to explain a and abnormal pupillary responses. Patients with patient’s symptoms. Ockham’s razor in diplopia will have abnormal eye movements. medical diagnostics is an example of a heu- Patients who have complaints of weakness or ristic, an intuitive approach or educated numbness caused by spinal cord involvement guess or common sense rather than a for- (myelitis) will have diminished strength, sensation, mal and rigid approach to a problem. and increased deep tendon refl exes in their arms 2 Laboratory Findings 51 and legs. In addition, some patients with CIS will (unidentifi ed bright objects). It is sometimes have evidence of more than one area of involve- diffi cult to determine whether unexpected areas ment of the CNS. For instance, a patient with new of brightness on the MRI in individuals over the symptoms of leg weakness referable to a spinal age of 40 represent worrisome areas or benign cord lesion might have abnormal pupils on exam- UBOs. White matter lesions are nonspecifi c and can ination consistent with previous, but asymptom- be seen in individuals with hypertension, migraine, atic, involvement of an optic nerve. and a variety of other conditions ( Inset 5.2 ). Inset 5.2 A 34-Year-Old Construction Worker 2 Laboratory Findings with Leg Weakness Incorrectly Diagnosed as MS 2.1 Routine Studies: Blood, Urine, Chest X-Ray JH was a 34-year-old male construction worker who began to develop diffi culty with MS is limited to the CNS, so blood analysis should decreased strength in his legs at work a few be completely normal. Standard blood tests (elec- weeks prior to admission to University trolytes, BUN, glucose, metabolic panel including Hospital. As a construction worker whose liver function tests, complete blood count with job entailed heavy manual labor, he needed differential) are a necessary part of the initial full strength in his legs. His weakness pro- diagnostic evaluation. Abnormalities such as ane- gressed and he came to the ER of a local mia, an elevated white count, or abnormal liver hospital because he could no longer work. function tests should prompt an evaluation that On examination in the ER he had weakness might identify an alternative disease process. in the legs and increased refl exes. Because Occasionally, a urinary tract infection (UTI) trig- of an abnormal spinal cord MRI scan, with

a gers an attack. If an UTI is not present, urine test- cervical white matter lesion, he was given a ing should be normal. Elevated protein or glucose diagnosis of multiple sclerosis, placed on in the urine or blood would be of concern for corticosteroids and discharged home after another disease process. A chest X-ray can pick 5 days of treatment. However, his weakness up a number of mimics of MS (e.g., neurosarcoi- progressed and he was admitted to the dosis, metastatic cancer, or infections such as University Hospital ER. History revealed tuberculosis or fungal infections). that he had been previously healthy. He had come to the USA from Ecuador and had been living in the USA for 2 years. On examination, he had marked weakness in his 2.2 CNS Imaging legs, primarily in the iliopsoas and quadri- ceps and had increased deep tendon refl exes The test which is the most helpful, but is also and a Babinski sign. Imaging of his cervical most frequently misinterpreted, is the MRI scan and thoracic spine revealed enhancing of the brain. The fi nding of white matter lesions lesions, but most were felt to be extramedul- (white matter lesions) on an MRI of the brain or lary. MRI of his brain was consistent with spinal cord is highly sensitive, but not specifi c for neurocysticercosis. Surgical exploration the diagnosis of MS (see Inset 5 .2 ). Thus, a size- revealed multiple extradural masses which able majority of patients who ultimately develop were cysts of the racemose form of neuro- MS will have white matter lesions on brain MRI, cysticercosis. He was treated with surgical but the presence of some white matter lesions, excision of the cysts, and on treatment with especially in a middle-aged population is not rare albendazole and corticosteroids, his clinical in individuals who do NOT have MS. White mat- condition slowly improved. ter lesions which have no apparent pathological signifi cance are sometimes referred to as “UBOs” (continued) 52 5 Multiple Sclerosis: Diagnosis Inset 5.2 (continued) refl ex. Our review of her previous MRI of Author’s note . This patient’s story accentu- the brain revealed it to be suboptimal tech- ates the necessity of being particularly cau- nically. The brain MRI was repeated, this tious in making a diagnosis of MS in a time on a closed MRI, showing a few patient with involvement of only one clini- periventricular white matter lesions. An cally defi ned area of the central nervous MRI of the cervical spine revealed two system. This patient’s presenting symp- parenchymal white matter lesions, a lumbar toms were solely referable to the cervical puncture revealed oligoclonal bands, and spinal cord. The case also demonstrates the the anti-aquaporin antibody test was nega- fact that white matter lesions are seen in tive, making the diagnosis of neuromyelitis many other diseases besides MS. optica less likely. We felt that she had defi - nite MS, and she was begun on interferon-b therapy. Subsequent follow-up in the years following the initial evaluation confi rmed the diagnosis of MS. Inset 5.3 A 38-Year-Old Woman with a Author’s note . By having two or more Possible Diagnosis of MS attacks with objective clinical evidence of two or more lesions, the patient fulfi lls A 38-year-old woman came to the MS McDonald’s criteria for MS, and the initial Center at University Hospital with symp- neurologist did not have to confi rm the toms of left leg weakness and the question diagnosis of MS with an MRI of the brain. of diagnosis of MS. Four years previously, We performed extra testing to confi rm the she suddenly developed decreased vision diagnosis, and each test was consistent with in the right eye associated with eye pain. the diagnosis of MS. This had been evaluated and found to be This patient’s story demonstrates two optic neuritis which resolved spontane- lessons. First, that all patients with MS do ously. Two months prior to her presentation not have to have MRI lesions in the brain at at the MS Center, she had developed left onset of their disease, i.e., the clinical history leg weakness with numbness and tingling and fi ndings on exam can be suffi cient to in both her left and right legs. Her primary make the diagnosis. Second, the quality of care physician referred her to a neurologist MRIs of the brain are important in looking who suspected MS and obtained an MRI of for white matter lesions, and suboptimal the brain, which was read as normal. scans, i.e., inadequately sensitive scans, However, the brain MRI was obtained on an can be potentially counterproductive in the “open” MRI, since the patient was claustro- evaluation of patients with possible MS. phobic, and “open” MRIs are known to be less sensitive. The neurologist was loathe to make the diagnosis of MS with the nor- mal MRI, and scheduled the patient for a The presence of white matter lesions on MRI is 6-month follow-up visit. The primary care by far the most signifi cant fi nding in many physician then referred her to our center. patients referred to neurologists for possible MS. On examination at our center she had The MRI appearance of white matter lesions mild optic atrophy and decreased visual depends on the peculiarities of myelin, water mol- acuity in the right eye, 4/5 weakness prox- ecules, and magnetic fi elds. Myelin is a tissue with imally in the left leg, hyperrefl exia and a very high lipid content and a low water content. clonus in the left leg and a left Babinski When myelin is lost, it is replaced by tissues that have a relatively high water content. Since such a 2 Laboratory Findings 53 large part of the MRI is based on water mole- cules, replacement of the very low water signal in normal myelin by the increased water signal in damaged myelin is striking. Abnormal character- istics of brain tissue in patients with MS other than increased water signal, such as axonal injury, infl ammation, and atrophy are diffi cult, if not impossible to visualize on routine MRI. There are no specifi c brain MRI patterns which are 100% diagnostic of MS, but some character- istics of white matter lesions are very helpful diagnostically. Lesions which are adjacent to the ventricles of the brain, especially those which are aligned perpendicularly to the ventricles and are fl ame-shaped, sometimes called “Dawson’s fi n- gers,” are particularly suggestive (Fig. 5.1 ). Fig. 5.1 Dawson’s fi nger. James Walker Dawson (1870– Although most large lesions occur in the deep 1927) was a Scottish physician whose work provided an white matter of the brain, smaller juxtacortical invaluable link between Charcot’s studies in the late nine- teenth century and those in the twentieth century. He sys- lesions, involving white matter connecting areas tematically characterized the pathology of MS lesions and of cortical gray matter, are increasingly being described the tendency of lesions to form along large recognized. These may be increasingly identifi ed periventricular veins. These lesions, whose long axis tends as higher resolution MRI scanners using larger to be perpendicular to the ventricules when seen on MRI, on the sagittal section shown in this fi gure, are called magnets come into wider use. These lesions may “Dawson’s fi ngers,” in tribute to his major contributions to be especially relevant to the progression of dis- the fi eld ability, such as cognitive dysfunction. The power of a magnetic fi eld is measured in a unit called a Tesla after Nikola Tesla, who was a Serbian MRIs in a patient over time depicted in Fig. 4.2 . inventor and electrical engineer, responsible for Over the course of weeks to months after the onset the discovery or development of a number of of a new lesion, the blood–brain barrier will return advances including alternating current, electro- to normal and the lesion will no longer be “gado- magnetic fi elds, wireless communication, and linium-enhancing.” Some patients with MS will robotics. The MRIs most commonly used now by frequently have gadolinium-enhancing lesions on neurologists have magnetic fi elds of 0.5–1.5 T, their brain MRIs and others only rarely so. Thus, but many centers have 3 T magnets, and a limited the absence of a gadolinium-enhancing lesion number of MRI facilities, mostly in research set- does not contradict a diagnosis of MS. However, tings, currently use 7 or 8 T magnets. the presence of one or more such lesions does aid F requently, neurologists concerned with the in the diagnosis. Gadolinium enhancement is not possibility of MS will also request that the MRI of specifi c for MS and can occur in a variety of dis- the brain be supplemented with an MRI sequence eases. However, the combination of typical using an intravenous contrast agent, standardly a “Dawson’s fi ngers” on MRI along with gadolin- chelated gadolinium compound. With gadolin- ium enhancement of one or more white matter ium-enhanced MRI, a recent MS lesion may dem- lesions is highly suspicious for MS. onstrate enhancement since the compound will Of all the tests involved in attempting to leak out into the lesion in the presence of disrupted ascertain the diagnosis in a patient with a neuro- blood–brain barrier around areas of active infl am- logical event looking like CIS, the MRI of the mation. On MRI scanning the leaked gadolinium brain is arguably the most important, because of will appear as one or more circular or spherical its high predictive value for the development of areas of brightness; this can be seen on the serial MS. In a patient presenting with a clinical 54 5 Multiple Sclerosis: Diagnosis syndrome indicating infl ammation of the optic nerve, brainstem, or spinal cord and periventricu- lar white matter lesions in the brain typical of MS, the chance of developing MS is extremely high. Thus, in the fi rst study of treating CIS with an MS disease-modifying drug, the CHAMPS study [1 ] , an inclusion criterion was the presence of two or more clinically silent lesions of the brain at least 3 mm in diameter on MRI scans and characteristic of multiple sclerosis with at least one lesion being periventricular or having an ovoid shape. This criterion was included because the investigators wanted a group with a high like- lihood of developing defi nite MS, and indeed in the relatively short 3-year follow-up of the study, 50% of patients in the placebo-treated group developed defi nite MS, a number which would have likely been lower had the inclusion criteria not included the brain MRI lesion requirement. Fig. 5.2 Oligoclonal bands (OCBs) are related popula- 2.3 Cerebrospinal Fluid Analysis tions of immunoglobulins in the CSF ( right lane , below) that travel together on a special type of gel called IEF (iso- electric focusing) and indicate the production of IgG The most frequent abnormality in the CSF of MS within the CNS. The l ane to the left represents a similar patients is the presence of oligoclonal immuno- treatment of serum from an MS patient showing the globulin bands (OCBs) in the CSF not present in absence of OCBs the serum. This fi nding occurs in more than 95% of MS patients [2 ] when optimum methodologies for OCBs are used. OCBs consist of immuno- indeed be a chronic infection. The precise basis globulin G, similar in size and charge, which for the prominent immunoglobulin production travel together on isoelectric focusing gel within the CNS remains unexplained, but recent electrophoresis (Fig. 5.2 ). Although OCBs are evidence points to the proclivity of the CNS to not specifi c for MS and occur in neurological support antibody production and downregulate infections such as neurosyphilis, in the proper cellular immune reactions. clinical setting their presence almost always MS is an infl ammatory disease with mononu- confi rms a diagnosis of MS in a patient with a clear cells, lymphocytes and monocytes, infi ltrat- borderline clinical presentation [3 ] . Since the ing the brain. This infi ltration is mirrored frequently blood–brain barrier usually prevents signifi cant by a modest increase in lymphocytes in the CSF, amounts of serum IgG from entering the brain often associated with a slightly elevated protein and CSF, CSF OCBs are products of IgG produc- level Although elevated mononuclear cell counts tion within the

CNS. Plasma cells, the terminally and protein are common in MS, they are not so differentiated B cells which produce immuno- invariable that their absence argues against the globulin, are a prominent part of many MS diagnosis. In fact, one of the mysteries of MS is lesions, and nests of plasma cells have occasion- that the brain parenchyma can be highly infl amed ally been identifi ed in the meninges of MS while mononuclear cells and normal protein are patients. Plasma cells in the CNS and OCBs in absent or only marginally elevated in the CSF. High the CSF in diseases other than MS are a feature of CSF mononuclear cell counts greater than 100 in chronic CNS infections, suggesting that MS may the CSF strongly suggest an alternative diagnosis. References 55 This disconnection between parenchymal infl am- practice. These are an advance in that they include mation and infl ammatory cells in the CNS indicates MRI data. An instance of the usefulness of the that in this disease the CSF is not invariably a good McDonald criteria is the patient who has CIS, measure of the severity of CNS infl ammation. with one attack and objective clinical evidence of only that one lesion but with multiple MRI lesions Patients in whom the diagnosis of MS can be (“dissemination in space”) and the development made at the fi rst visit to the neurologist . Some of new MRI lesions over time (“dissemination in patients present to the neurologist not with their time”). This patient qualifi es as having the diag- fi rst attack but with their second or third. Their nosis of defi nite MS by McDonald criteria months earlier neurological episodes may have been or years before the second attack. Some MS neu- ignored or may have been misdiagnosed. rologists mistrust the McDonald criteria [5 ] , and Evidence of accumulated damage to the CNS and for community neurologists the emphasis on MRI previous attacks in such patients can aid in mak- can be diffi cult, but for many neurologists they ing the diagnosis of MS. have become the standard for diagnosis. Criteria for defi nite MS . The fi rst commonly accepted diagnostic criteria, the Schumacher cri- References teria, developed in 1965, were purely clinical and stressed the importance of dissemination in space 1. Jacobs LD, Beck RW, Simon JH, et al. Intramuscular and time. They can be summarized in one sen- interferon beta-1a therapy initiated during a fi rst demy- tence: two or more lesions demonstrable in the elinating event in multiple sclerosis. CHAMPS Study white matter of the central nervous system sepa- Group. N Engl J Med. 2000;343(13):898–904. 2. Link H, Huang YM. Oligoclonal bands in multiple rated in time (by at least 6 months) and space, i.e., sclerosis cerebrospinal fl uid: an update on methodol- location within the CNS, with objective abnor- ogy and clinical usefulness. J Neuroimmunol. 2006; malities on the neurological examination, without 180(1–2):17–28. an alternative diagnosis. Subsequently, the Poser 3. Thompson EJ, Freedman MS. Cerebrospinal fl uid anal- ysis in the diagnosis of multiple sclerosis. Adv Neurol. criteria incorporated laboratory testing, creating 2006;98:147–60. categories of “laboratory-supported” defi nite or 4. Polman CH, Reingold SC, Edan G, et al. Diagnostic cri- probable MS. More recently, the McDonald crite- teria for multiple sclerosis: 2005 revisions to the ria for the diagnosis of defi nite MS [4 ] (h ttp:// “McDonald Criteria”. Ann Neurol. 2005;58(6):840–6. 5. Poser CM, Brinar VV. Diagnostic criteria for multiple www.mult-sclerosis.org/DiagnosticCriteria.html ) sclerosis: an historical review. Clin Neurol Neurosurg. have been utilized both in clinical trials and in 2004;106(3):147–58. Multiple Sclerosis Mimics 6 Although the course of the disease in all MS patients is different, most MS patients present in Inset 6.1 A Patient with Known MS and a New fairly straightforward manner, so that the diagno- Neurological Event—Most Likely MS, But… sis is usually made soon after fi rst presentation to KW, a 34-year-old emergency room physi- a neurologist. However, sometimes the diagnosis cian with an 8-year history of MS, presented is incorrect, either because the patient has another to her neurologist for emergency evaluation disease process and MS is mistakenly diagnosed, because of weakness and numbness in her or less commonly because the patient has MS and arms. Her exam revealed weakness and another diagnosis is erroneously made. This sensory changes in the arms; there was also chapter discusses the diseases that most com- decreased strength in her legs. Since in pre- monly mimic MS. The confusion usually occurs vious attacks she had cervical spinal cord at the time of the fi rst neurological event, clini- involvement, it was assumed that she was cally isolated syndrome (CIS), rather than in having a spinal cord attack and she was patients who have had previous events. CIS, as treated with intravenous corticosteroids. previously discussed in Chaps. 4 and 5 , is the She improved but not completely. She con- sudden development of a demyelinating and tinued to be symptomatic and had diffi culty infl ammatory event, consistent with a fi rst attack at work with suturing and other tasks involv- of MS, that does not meet criteria for clinically ing fi ne motor control in her hands. An MRI defi nite MS. Thus, optic neuritis or myelitis or a scan of the cervical spine showed both an hemisensory syndrome in a young, previously acute MS plaque at C3-5, and, in addition a healthy individual might be CIS or one of the large central cervical disc herniation at C5 other diseases outlined in the chapter. If the causing cord compression. She underwent patient with CIS develops new MRI lesions or decompressive surgery for the disc and has new attacks, the diagnosis of MS is much less had complete recovery of her strength and diffi cult. Some issues and diffi culties involved in sensation in her arms and legs. differential diagnosis of the CIS patient are high- lighted in a recent clinical review of six German Author’s note . Most acute neurological patients with CIS [2 ] . Some examples of diseases events localizing to the CNS which occur that have clinical, imaging, or CSF characteris- in patients with MS are rightly assumed to tics similar to MS are summarized in Table 6 .1 . be MS attacks. However, patients with Finally, not all symptoms localizing to the CNS MS are not immune from other disease in patients with known MS should automatically processes. In this patient, two processes, an be assumed to be a new attack of MS, as exempli- fi ed by the patient in Inset 6 .1 . (continued) A.R. Pachner, A Primer of Neuroimmunological Disease, 57 DOI 10.1007/978-1-4614-2188-7_6, © Springer Science+Business Media, LLC 2012 58 6 Multiple Sclerosis Mimics Table 6.1 Similarities of MS to some other common diseases Clinical MRI brain CSF oligoclonal Relapsing– Disease Prevalence characteristics characteristics bands remitting Stroke Common ++ + − − ADEM Rare ++ ++ + − Neurosarcoidosis Rare + + + + Lyme Common + − + − neuroborreliosis (in endemic areas) HIV/OI Common + + + − SLE/APS Rare + + − + Migraine Common − + − − Lymphoma Rare + + + + Systemic vasculitis Rare + + + + ADEM acute disseminated encephalomyelitis; H IV/OI human immunodefi ciency virus or its opportunistic infections; SLE/APS systemic lupus erythematosus/anti-phospholipid antibody syndrome factors stroke mimicking MS can occur from Inset 6.1 (continued) unusual causes of stroke, such as the patient with an atrial myxoma described in Inset 6 .2 . active MS plaque in the cervical cord and a cervical disc, were present which together resulted in a very symptomatic patient. Her Inset 6.2 A 50-Year-Old Woman with Double symptoms only resolved after both pro- Vision: Stroke Mimicking MS cesses were addressed. BE was a 50-year-old woman with no previ- ous medical history when she presented to a hospital emergency room with double 1 Cerebrovascular Disease/ vision. Six months previously, she had vis- Stroke ited her primary care doctor for an episode of severe vertigo and nausea which began to In any community within the USA or Europe, the improve spontaneously after 4 days and most common cause of rapid onset of a neuro- resolved after 2 weeks. Her examination logical defi cit, combined with focal lesions on was consistent with a very mild internuclear MRI, is not MS, but cerebrovascular disease. ophthalmoplegia (INO) and she had no other Thus, it is not surprising that patients with stroke fi ndings on examination. On the basis of are sometimes diagnosed as having MS and vice multiple brain MRI white matter lesions and versa. This is increasingly true now in the USA no alternative diagnosis, she was diagnosed for two reasons: fi rst, the MRI is being used more with multiple sclerosis, despite negative oli- and more in evaluating neurological symptoms, goclonal bands in the CSF. She was offered and second, it can be diffi cult to distinguish white MS therapy, which she decided not to take. matter lesions in the brain MRI caused by cere- She was subsequently evaluated by two brovascular disease from those caused by MS. neurologists who felt that she had probable The population in whom this is usually a problem multiple sclerosis. are patients between 40 and 60 years old, for Seven months after her episode of dou- whom underlying precipitating factors such as ble vision, she was found to have an hypertension, diabetes, hyperlipidemia, and absent radial pulse in her left arm which smoking may have predisposed to atherosclero- turned out to be due to a clot in the radial sis, but the patient is still young enough that mul- artery. Investigation for a source of the clot tiple sclerosis must be considered. Alternatively, in a young patient without obvious predisposing (continued) 1 Cerebrovascular Disease/Stroke 59 4. MS patients frequently have evidence by MRI Inset 6.2 (continued) of lesions in their spinal cords, while stroke revealed a mass in her heart, which proved patients almost never do. to be an atrial myxoma, a benign cardiac 5. Acute MS lesions often enhance after gado- tumor which can send emboli to the brain. linium injection, while enhancement is less She underwent surgery for removal of the commonly seen in stroke lesions. myxoma, and had no further symptoms. In In other patients who come to the attention of retrospect, the white matter lesions in her their physicians for nonspecifi c sensory symptoms brain represented sites of embolic infarc- tion not MS lesions, and the episodes of Inset 6.3 A 37-Year-Old Woman with Acute neurological symptoms were ischemic Severe Left-Sided Weakness—MS Mimicking from emboli not MS attacks. Stroke Author’s note . This patient had a pattern SB was a 37-year-old woman who pre- resembling MS when she presented with sented to the hospital with a left hemipare- double vision, despite turning out to have sis. She had a history of a prior stroke embolic strokes caused by the tumor in her causing right hemiparesis 3 years previ- heart. At presentation, her age was a bit ously, which had resolved to a great extent high for the typical initial diagnosis of MS and she was ambulatory with a cane prior but not inordinately so. However, at that to admission. Because of the history of the age, and with a negative spinal tap, the previous stroke and an elevated blood pres- diagnosis should have been in question. sure on admission, the diagnosis of a right hemispheric stroke was made, and she was Another reason that stroke can be confused admitted to the hospital’s stroke ward. with MS is that stroke can satisfy Schumacher’s After the fi rst few days, the patient did not criteria for MS, i.e., at least two separate CNS improve and an MRI scan of the brain was events disseminated in time and space. performed with diffusion studies and gado- Schumacher’s criteria also include the fact that linium injection. There was no area of there must be no better explanation for the neuro- restricted diffusion, which would have been logical picture, but sometimes the diagnosis of consistent with an acute stroke, but there was stroke is not considered a “better” explanation. An gadolinium enhancement of a number of example of how a young woman was mistakenly lesions, consistent with active MS plaques. diagnosed as having strokes and actually

had MS Cervical cord MRI and triple evoked is provided in Inset 6 .3 . Thus, for the reasons out- responses and CSF analysis were consistent lined above, in addition to the fact that it is so com- with MS, and CT angiogram, showed no mon, stroke is the most frequent mimic of MS. cerebrovascular disease. A lumbar puncture A few distinguishing features are listed below: was performed and the CSF revealed positive 1. MS patients are usually young individuals oligoclonal bands; a diagnosis of MS was who are healthy other than their MS, while made. It was felt in retrospect that the “stroke” stroke patients usually are older and have risk at age 34 was her fi rst attack of MS. factors for stroke, such as hypertension, dia- Author’s note . The physicians seeing this betes mellitus, smoking, and hyperlipidemia patient in the ER made a mistake involving (high levels of lipids in their blood). the “anchoring heuristic,” in which the pre- 2. MS patients have oligoclonal Ig G bands in vious diagnosis of stroke was excessively their CSF >90% of the time, while stroke relied upon, without factoring in new infor- patients almost never have them. mation [ 16 ] . In diseases causing focal neu- 3. On MRI active MS lesions usually do not have rological lesions in young woman, MS increased signal on diffusion-weighted images, must be considered very high on the list. while strokes usually do. 60 6 Multiple Sclerosis Mimics or headache, an MRI is frequently obtained, at the turn of the twentieth century until World War white matter lesions are seen, and the patient is II and the availability of penicillin, syphilis treat- referred to a neurologist. The most common dis- ments were also used in MS. The rationale was that eases in which this occurs is migraine and hyper- both diseases caused signifi cant disability and, tension, and a competent history and examination since there was no treatment for MS, it was worth will generally quickly identify those patients. trying antisyphilitic therapies [4 ] . Neurosyphilis is less common now, but still occasionally causes diagnostic problems, as in the patient in Inset 6 .4 . 2 Neurological Infections The diagnosis can be made by positive syphilis 2.1 HIV Infection with HIV is often subclinical for an Inset 6.4 Meningovascular Syphilis Mimicking extended time period, and individuals with HIV MS: A 41-Year-Old Man with Trouble Talking frequently are immunodefi cient without symptoms until they get an opportunistic infection (OI). The A 41-year-old man presented to the ER with likelihood that OIs will get confused with MS is sudden development of dysarthria (diffi culty highly variable depending on geographic region. with motoric articulation of his words), right Generally, HIV OIs are infrequently confused with facial weakness, and left-sided weakness. MS, so the problem only becomes a signifi cant He had no signifi cant past medical history, one if the prevalence of HIV in a community is including no risk factors for stroke. His high. For example, in Newark, NJ, the prevalence examination revealed fi ndings consistent of HIV/AIDS in the general population is reported with a right pontine lesion. MRI of the brain to be 2–3%, so the likelihood for an OI and MS revealed a white matter lesion in his right being confused is higher than other areas where pons without mass effect as well as six white the HIV/AIDS prevalence is lower. The most com- matter lesions scattered throughout the brain; mon OIs which cause focal infl ammatory CNS none of the lesions were periventricular and disease mimicking MS are toxoplasmosis and pro- none enhanced with gadolinium. The initial gressive multiple leukoencephalopathy (PML). diagnosis of MS was made by the ER staff, Another disease affecting immunosuppressed with a number of other possible alternative individuals with HIV and which can mimic MS is diagnoses, and a lumbar puncture was per- primary CNS lymphoma, which some investiga- formed to confi rm the diagnosis. There were tors feel is caused by Epstein–Barr virus (EBV). 79 white cells/cu. mm. and an elevated pro- Toxoplasmosis and primary CNS lymphoma gen- tein. The CSF VDRL test, a test for syphilis erally have characteristic imaging appearances (see Chap. 13 ) was positive at 1:8 and the that do not look like MS, but PML can cause white serum VDRL was 1:16. Oligoclonal bands matter disease that can look very similar to MS. were positive. The patient’s wife was seroposi- Neurological involvement in HIV and its OIs and tive for syphilis also. Both were treated with primary CNS lymphoma are discussed in later penicillin. In follow-up, patient resolved his chapters in this book. fi ndings, the VDRL slowly dropped and fi nally became negative, and the patient had no further clinical or MRI lesions. 2.2 Neurosyphilis Author’s note . Neurosyphilis remains a clin- ically important problem, with prevalence Lord Brain’s seventh edition of his textbook on of the infection increasing in men who have neurology includes meningovascular syphilis and sex with men (MSM), and a masquerader of tabes as high on the list in the differential diagnosis other diseases. Had this patient’s physician of MS, possibly because of the fact that neurosyphilis not ordered a syphilis test, the diagnosis and was more common at that time [ 3 ] . In fact, from the proper therapy would have been missed. time effective syphilis treatments became available 2 Neurological Infections 61 tests in the CSF and blood; it must be remembered nent white matter disease in the brain or spinal that sometimes patients with neurosyphilis have cord seen on MRI scans is highly unusual for negative syphilis tests in the serum but positive LNB and thus tends to exclude the diagnosis. tests in the CSF. Neurosyphilis is discussed at Since many individuals in endemic areas can length later in Chap. 12 . have serum antibody positivity on the basis of exposure, a positive Lyme serology in the blood does not confi rm the diagnosis of LNB; thus, 2.3 Neurocysticercosis patients with MS in Lyme endemic areas can be seropositive on the basis of B . burgdorferi expo- Neurocysticercosis is a chronic CNS infection sure without active infection in the CNS. Lyme caused by ingestion of eggs of the tapeworm disease is discussed at length in Chap. 12 . Taenia solium . Pigs and humans are reservoirs of cysticercosis, and the disease in humans occurs in parts of the world in which there is a signifi - cant rate of infection in pigs. Most of the neuro- 2.5 Tropical Spastic Paraparesis cysticercosis cases in the USA are from Mexico, as the disease is endemic there in humans and Spinal cord involvement is common in MS. In pigs, as it is in many countries in Central and patients with spinal cord involvement who come South America. Since pigs in the USA do not har- from parts of the world endemic for the retrovi- bor Taenia solium , neurocysticercosis in the USA rus, human T-lymphotropic virus-1 (HTLV-1), will be seen generally in areas with a large immi- this infection should be considered as a possible grant population, and thus clinicians in those cause of myelitis along with MS. Myelitis due to areas must be aware of this multifocal CNS dis- infection by this pathogen is called tropical ease that can affect a young population and mimic spastic paraparesis (TSP) or HTLV-1-associated MS. The disease is treatable with the benzimida- myelopathy (HAM). Along with spinal cord zole compound, albendazole (see case of neuro- involvement, patients with TSP can have white cysticercosis in Chap. 5 ); praziquentel is also matter lesions in the brain on MRI, although effective, but costs more. these are not usually associated with clinical symptoms. The vast majority of individuals in endemic areas with positive anti-HTLV1 anti- 2.4 Lyme Disease bodies in the blood do not have TSP, so some- times HTLV-1 antibody positivity can occur in A chronic infection caused by various strains of patients with true MS. In such patients, it might the spirochete Borrelia burgdorferi , Lyme dis- be diffi cult to distinguish MS from TSP, espe- ease is a relatively common cause of illness in cially if the disease is primarily in the spinal endemic areas in the USA and Europe. There cord. TSP is discussed more fully in Chap. 12 . are differences between the American and European variants with serious neurological dis- ease more common in the European forms of the infection [ 5 ] . Because the illness is infl amma- 2.6 Tuberculosis tory and can be limited to the nervous system, in the occasional patient the disease can be mis- In parts of the world with a large burden of tuber- taken for MS. The diagnosis of Lyme neurobor- culosis (TB), such as India, the diagnosis of reliosis (LNB) can be made by the demonstration n eurological involvement with Mycobacterium of high levels of anti-B . burgdorferi antibody in tuberculosis, the TB bacillus, is often made as a the CSF and usually also in the serum in an indi- default in patients with neuroinfl ammatory dis- vidual who has had exposure to ticks in an area ease and anti-TB therapy is initiated. Thus, endemic for Lyme disease. In addition, promi- patients with MS presenting with a fi rst attack 62 6 Multiple Sclerosis Mimics 3 NMO Neuromyelitis optica (NMO), also called Devic’s disease, is a disease very similar to multiple scle- rosis, characterized by demyelination, infl amma- tion, and disability in young individuals. However, the clinically relevant lesions are gen- erally restricted to the optic nerves and spinal cord, in contrast to MS where they occur through- out the CNS, including the brain. On imaging, the lesions in the spinal cord are “longitudinally extensive,” meaning that they are longer than a few vertebral levels, in contrast to MS, where they generally span fewer than three vertebral levels. Patients with NMO generally have no or Fig. 6.1 CNS TB lesion. Tuberculosis infection in the very few lesions on brain MRI, and oligoclonal brain can appear as a tuberculoma on MRI scanning, bands are positive in only 25% of NMO patients although occasionally TB lesions can be confused with in contrast to the 95% positivity rate in MS. For MS lesions on brain MRI many years, it was considered a forme fruste of MS, but now this view is being challenged, and many neuroimmunologists consider it as being a can be diagnosed as having TB, anti-TB therapy completely different disease process. It is much is initiated, and the diagnosis is “confi rmed” by less common than MS. In France, the prevalence resolution of the neurological symptoms. This of MS is estimated at 1 in 600, similar to the scenario is not rare and can delay initiation of prevalence in the USA, while the prevalence of appropriate treatment for MS. Although usually NMO in France has been determined to be 0.2% CNS tuberculosis presents with different lesions of that, or approximately 1 case in 300,000 indi- that do not mimic MS (Fig. 6 .1 ), sometimes TB viduals [ 7 ] . In Japan, there is a variant of MS can present as multifocal white matter lesions called opticospinal MS, which in many patients which can mimic MS on MRI [6 ] . Tuberculosis is appears to be identical to the NMO described in discussed in more depth in Chap. 12 . Western countries, although it remains unclear whether NMO and opticospinal MS are the same entity. Other features of NMO are discussed in 2.7 Brain Abscess Chaps. 8 , 17 – 19 . There has been a great deal of excitement Since brain abscesses are frequently multifocal because of progress over the last decade in eluci- and usually present weeks after the initial bacter- dating the pathogenesis of NMO. It is character- emia, brain abscesses sometimes present as a ized by the presence of an autoantibody in the new neurological defi cit without a known ante- serum, occurring in the majority of NMO patients, cedent infection, along with multifocal lesions on which is detected by its ability to bind aquaporin-4 MRI mimicking MS. Generally speaking, MRI channels in the brains of mice (see Chap. 17 for a imaging and the clinical situation can distinguish description of aquaporins and Chap. 18 on the the two

processes, but occasionally patients have NMO antibody assay). Models of NMO have been required brain biopsy for the diagnosis. Also, recently induced in rodents by transfer of IgG patients with very aggressive MS with large from the serum of patients with NMO, providing lesions, sometimes called tumefactive MS, can evidence that the autoantibody may be pathogenic be misdiagnosed as having brain abscesses. and responsible for the clinical phenotype [8 , 9 ] . 6 Other Conditions 63 These fi ndings, as well as a plethora of new para- neoplastic syndromes identifi ed as being antibody- 5 Leukodystrophies mediated (see Chap. 14 ), have raised the possibility that at least some of the CNS injury in multiple The most dramatic and obvious fi nding in MS, sclerosis may be autoantibody-mediated, as well especially on imaging, is demyelination. Thus, it as in other neuroimmunological diseases of is not surprising that hereditary disorders of white unknown pathogenesis. matter, also called leukodystrophies [1 ] , can be For the practicing neuroimmunologist, it is misdiagnosed as MS. Usually, neurologists do important to distinguish NMO from MS because not consider leukodystrophies as a cause of white the therapies are different for the two diseases. matter disease in adults because leukodystrophies In contrast to MS, where initial therapy is usu- are most often overwhelmingly debilitating and ally interferon- b , glatiramer acetate, or fi ngoli- rapidly progressive diseases in infants and chil- mod, the recommended therapy for NMO is dren. However, recently, there has been increas- plasmapheresis and immunosuppressive agents, ing appreciation that leukodystrophies in adults although the effectiveness of these therapies has are occasionally misdiagnosed as MS [1 ] . Many not been proven. It is generally assumed that adult-onset leukodystrophy patients present with recurring attacks in NMO result in progressive predominantly cognitive symptoms consistent injury, in contrast to MS where the link between with a subcortical dementia. Late stages are char- attacks and progressive disability is less clear. In acterized by incontinence, abulia, and increased NMO, immunosuppressive therapy with myco- spasticity. Although adult-onset leukodystrophies phenolate mofetil has resulted in decreased do not generally have clinical pictures consistent attacks [1 0, 11 ] . with relapsing–remitting MS, they can mimic primary progressive MS, in which progressive disability dominates the clinical picture. 4 ADEM 6 Other Conditions As mentioned in Chap. 3 , post-vaccinial enceph- alomyelitis, one of a group of diseases called 6.1 Neurosarcoidosis acute dissseminated encephalomyelitis (ADEM), was the illness which established the fi eld of Sarcoidosis is an infl ammatory disease affecting a neuroimmunology. Usually occurring in chil- wide range of organ systems including the ner- dren, ADEM can only be reliably separated from vous system and is discussed again in Chap. 1 3 acute, highly infl ammatory MS by the fact that among the systemic infl ammatory diseases. ADEM is a monophasic event, while MS recurs Neurosarcoidosis is infl ammatory, frequently and progresses. Other differences are that with white cells and oligoclonal bands in the CSF ADEM usually occurs days to weeks after a mimicking MS. Multifocal white matter lesions well-defi ned acute infection or a vaccination and cranial nerve palsies, especially optic neuri- and can cause encephalopathy and seizures, fea- tis, may occur. It is, therefore, sometimes con- tures which usually do not occur in MS. fused with MS. In a recent study of 3,900 patients Occasionally, ADEM patients have one or more referred to Vanderbilt’s MS center over 13 years, relapses within a few months after the initial the clinicians there saw 52 patients who had neu- event without developing MS; this presentation rosarcoidosis instead of MS [ 13 ] . The diagnosis is sometimes called multiphasic disseminated of sarcoidosis is generally made by demonstrat- encephalomyelitis (MDEM). The clinical char- ing infl ammation on biopsy of affected lymph acteristics of 28 children with ADEM, 7 with nodes, liver, nerve, or skin, with characteristic MDEM, and 13 with MS have recently been non-caseating granulomas. MRI scans of the brain reviewed [1 2 ] . usually reveal meningeal enhancement which is 64 6 Multiple Sclerosis Mimics Fig. 6.2 MRI of the brain in neurosarcoidosis. (a ) Sagittal cisterns, affecting the cisternal segments of the cranial and (b ) axial post-gadolinium images demonstrating thick, nerves. Note the enhancing nodules along the interpedun- irregular, and nodular leptomeningeal enhancement, which cular, crural, and pre-pontine cisterns along the course of is more striking along the basilar and perimesencephalic cranial nerves III, VI, V, and VI, respectively frequently nodular, or diffuse intraparenchymal infl ammatory lesions (Fig. 6.2 ). Alternatively, with nonsteroidal anti-infl ammatory drugs there may be diffuse white matter lesions indistin- (NSAIDs) with some relief, and ultimately guishable from MS as in the patient in Inset 6 .5 . resolved without recurrence. About 5 years prior to this evaluation, she developed pain and diffi culty with Inset 6.5 Neurosarcoidosis Mimicking MS—A vision in both eyes, diagnosed as uveitis, 49-Year-Old Woman with White Matter Lesions and was treated with eye injections, eye and a History of Hearing Loss drops, and oral prednisone. Over the year EF was a 49-year-old woman referred to prior to this evaluation, she has had worse our MS center because of an MRI scan read headaches than usual, responding par- as likely multiple sclerosis. tially to NSAIDs. Because of the head- She was well until 19 years prior to the aches, she underwent an MRI of the brain evaluation. Shortly after delivering her fi rst which revealed multiple white matter child she developed progressive complete lesions, read as highly suggestive of MS. loss of hearing on the left side over a few None of the lesions enhanced with gado- weeks and underwent an MRI scan of the linium injection. She had not noted any brain. This showed multiple white matter signifi cant numbness or weakness, gait lesions, and she was told it was possible unsteadiness, or any other neurological MS. She did not return to the neurologist for symptoms other than the diffi culty with follow-up. The hearing loss slowly improved vision which had been attributed to without treatment, but she remained with uveitis. Neurological evaluation was neg- mildly decreased hearing on the left. ative except decreased vision. Ten years prior to the evaluation she began Initial evaluation was felt to be consistent to experience episodes of severe arthritis last- with sarcoidosis, and she underwent a gal- ing a few weeks to a few months, c onsisting lium scan which revealed infl ammation in her of knee or ankle swelling, pain, and limita- minor salivary glands and lacrimal glands. tion of activity. These episodes were treated These were biopsied, revealing infl ammation (continued) 6 Other Conditions 65 tracts [1 4 ] . The disease usually does not fl uctuate, Inset 6.5 (continued) and although rare, it always must be considered in and noncaseating granulomas, confi rming the differential of MS because it is completely the diagnosis. Chest X-ray showed hilar ade- treatable by supplementation with vitamin B12. nopathy. A lumbar puncture revealed a lym- phocytic pleocytosis and no oligoclonal bands. For her uveitis and headache, she was 6.3 Other Neuroinfl ammatory treated with methotrexate and alternate day Diseases corticosteroids. Over a follow-up of 4 years, her uveitis Some diseases are so rare that they are normally and meningitis improved and she was able only considered far down the list of likely sus- to be taken off the medications. Her MRI of pects. These are sometimes called “zebras”; a the brain was repeated 4 years after initial zebra is an extraordinarily rare disease presenta- evaluation and showed no increase in white tion that has an extremely low probability of matter lesions. being the ultimate diagnosis in a certain presenta- tion and comes from the phrase: “When you hear Author’s note . Most MS patients are quite hoofbeats, think horses, not zebras.” Some neu- healthy on presentation, with the exception roimmunological rare diseases that have impor- of their problems in the central nervous tance beyond their prevalence will be discussed system. This patient had had infl ammation in Chap. 16 . “Zebras” that have been very rarely in her joints and in her uvea, problems not confused with MS include infl ammatory diseases usually associated with MS, although an (Sjogren’s syndrome, Behcet’s disease, isolated occasional MS patient can have an associ- CNS vasculitis and systemic vasculitides such as ated uveitis. In addition, she had hearing Wegener’s granulomatosis or Churg–Strauss vas- loss as an initial problem, a symptom which culitis) and diseases without infl ammation is very unusual in MS. The biopsy con- (CADASIL and Susac’s syndrome). Although fi rmed that the patient had an alternative these diseases may have characteristics that explanation for her symptoms. resemble MS in an acute presentation, their natu- ral history is generally quite different from MS. The neuroinfl ammatory diseases will be described in other chapters, and CADASIL and Susac’s will 6.2 Subacute Combined be discussed below. Degeneration CADASIL is the acronym for cerebral auto- somal dominant arteriopathy with subcortical This is a rare but highly treatable cause of demy- infarcts and leukoencephalopathy. It is the most elination of the dorsal and lateral columns of the common heritable cause of stroke and vascular spinal cord, caused by vitamin B12 defi ciency. dementia in adults and is associated with a muta- This is usually due to pernicious anemia, an auto- tion in the Notch 3 gene. This gene encodes for a immune disease in which there are antibodies to transmembrane receptor, and the mutations caus- the parietal cells of the stomach, leading to inade- ing CADASIL result in an odd number of cysteine quate secretion of intrinsic factor, a glycoprotein repeats in that protein. It is felt that the underly- required for vitamin B12 absorption in the intes- ing pathology is a chronic subcortical ischemia: tines. As the vitamin B12 levels drop, patients usu- Notch 3 forms aggregates around cerebral blood ally develop sensory defi cits, weakness, ataxia and vessels. The patient referred to our MS center postural instability, and sphincter disturbances. described in Inset 6 .6 was not unusual in that the More acute presentations of days or a week or two disease is frequently associated with migraine have been described. The pathology is usually in with auras and with accumulating subcortical the posterior columns and lateral corticospinal white matter lesion burden. 66 6 Multiple Sclerosis Mimics Inset 6.6 Multifocal White Matter Disease on location and the absence of oligoclonal MRI Scanning in a Patient with Frequent bands on the spinal tap all supported the “Migraines” diagnosis of CADASIL, despite the fact MH was a 37-year-old right-handed woman that CADASIL is much less common than when she was referred to our MS center by MS. CADASIL is rare, and this was the her local neurologist for the question of the only patient I have ever cared for in whom diagnosis of MS. I have made that diagnosis. She had sought his attention a few years prior when she began having increasingly frequent episodes of what she called her Susac’s syndrome . Susac’s syndrome (SS) “migraine,” a severe throbbing headache consists of the clinical triad of encephalopathy, preceded by a visual image of gold spinning branch retinal artery occlusions, and hearing loss in her eye, and numbness and tingling in her [ 15 ] . The disease is caused by a small blood ves- arms and legs. These occurred about once a sel disease affecting the eyes, but the underlying month. The sensations of numbness and tin- etiology is unknown, and it is not clearly neu- gling never occurred without the headaches. roinfl ammatory. It may be post-viral since many She had several MRIs of the brain which cases spontaneously improve, but the recom- initially showed a small number of white mended therapy is immunosuppression for the matter lesions, most of them subcortical acute infl ammatory syndromes. and not periventricular, but then an increas- ing number over time; none ever enhanced with gadolinium. The rest of the history was References negative, including the absence of stroke risk factors, except that the family history 1. Costello DJ, Eichler AF, Eichler FS. Leukodystrophies: was positive for strokes and migraines in a classifi cation, diagnosis, and treatment. Neurologist. number of relatives. Her neurological 2009;15(6):319–28. examination was normal. Evoked responses 2. Tumani H, Sapunova-Mayer I, Sussmuth SD, Hirt V, Brettschneider J. CIS case studies.

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Curr Treat Options Neurol. 2008;10(1): WW, Quezado ZMN. Potential outcome factors in 55–66. subacute combined degeneration. J Gen Intern Med. 12. Dale RC, de Sousa C, Chong WK, Cox TC, Harding 2006;21:1063. B, Neville BG. Acute disseminated encephalomyeli- 15. Susac JO, Egan RA, Rennebohm RM, Lubow M. tis, multiphasic disseminated encephalomyelitis and Susac’s syndrome: 1975-2005 microangiopathy/auto- multiple sclerosis in children. Brain. 2000;123(Pt immune endotheliopathy. J Neurol Sci. 2007;257 12):2407–22. (1–2):270–2. 13. Pawate S, Moses H, Sriram S. Presentations and out- 16. Vickrey BG, Samuels MA, Ropper AH. How neurolo- comes of neurosarcoidosis: a study of 54 cases. QJM. gists think: a cognitive psychology perspective on 2009;102(7):449–60. missed diagnoses. Ann Neurol. 2010;67(4):425–33. Multiple Sclerosis Therapy 7 Lacking proof of the value of any form of therapy in multiple sclerosis, the average physician or neurologist is usually content to rely on a placebo . Douglas McAlpine, Multiple Sclerosis—A Reappraisal, 1965, p. 197 In long-term diseases, it can be diffi cult to execute randomized clinical trials (RCTs) which reach hard unambiguous effi cacy endpoints . Ebers et al. (2008) [1 ] The history of multiple sclerosis therapy is generally one of futility, consisting of many far- 1 Disease-Modifying Drugs fetched remedies, some of which have been painful or harmful or both. This is not surprising 1.1 How Medications Become given the variability of the disease among patients, Approved for Use in MS and even within the same patients, and considering 1. P reclinical studies . Most large pharmaceutical the relative inability of current therapy to reverse companies will have a department devoted to the disease. However, signifi cant advances have drug discovery, in which research is performed been made in MS therapy, which have made to identify possible therapies. These studies McAlpine’s pessimistic statement in 1965 out- are frequently performed in in vitro systems dated. The pessimism of previous times has been such as cell cultures, and will often include replaced by a fl urry of attempts to optimize mod- studies in animal models. Animal models for ern clinical trial design to identify effective treat- MS will be extensively discussed in Chap. 8 . ments. These attempts, which have come from a 2. Phase 0 studies . These are early pilot studies massive amount of investment by pharmaceutical of a new drug in a small number of human vol- companies and the extensive efforts of neurolo- unteers. They address relatively simple issues gists and allied health care workers, have led to of pharmacokinetics (PK) and pharmacody- the discovery of many effective therapies. These namics (PD), usually after only one adminis- therapies can be divided into two general catego- tration of the drug. ries. This chapter fi rst covers “disease-modifying 3. Phase 1 studies . These are usually called drugs (DMDs),” therapies which affect the under- safety and dose-fi nding studies, although they lying disease process. Next “symptomatic thera- also are designed to obtain more PK/PD data pies” are discussed, including life-style changes than could be obtained in Phase 0. Usually, which can benefi t the patient. low doses are initially used followed by A.R. Pachner, A Primer of Neuroimmunological Disease, 69 DOI 10.1007/978-1-4614-2188-7_7, © Springer Science+Business Media, LLC 2012 70 7 Multiple Sclerosis Therapy increasing amounts of drugs as low doses are currently being used for MS that is known found to be safe. to be effective. One reason for employing 4. Phase 2 studies . Whereas phase 0 and 1 an active comparator is that it is easier to involve small numbers of subjects, phase 2 recruit MS patients into a study when they generally involve larger numbers for longer know they will not receive a placebo. periods to try to address three issues: dosing, Another reason is the hope that the new safety, and effi cacy. drug will be superior to the old drug, and 5. Phase 3 studies . These are large, very expen- thus capture a large market share. An sive trials which establish the drug’s effi cacy example is the recently published and safety compared to either placebo or a gold TRANSFORMS study in which patients standard treatment. They are randomized, con- were randomized to fi ngolimod or inter- trolled trials (RCTs). RCTs have been a major feron-beta-1a (IFN-b -1a), and a placebo step forward for MS and have addressed the arm was not included [2 ] . problems with bias, blinding, and statistical A positive aspect of the change to using RCTs analysis of earlier “positive” studies of MS is that success of a new agent in an RCT gives therapies. Given the inherent variability of MS, considerable confi dence that the drug is indeed diffi culties in measurement, and strong placebo effective. A negative effect is that RCTs are very effects, RCTs are critical to assess effi cacy of a expensive. A result of this expense of the clinical new agent; they have now become the gold trials is that new drugs are tested for 2 years or standard. These studies generally incorporate less. This very short period of testing can be ade- the following characteristics: quate for testing for decreasing relapse rates but (a) T hey are randomized. When patients enter precludes the ability to test for effects on disabil- the study, they are randomly assigned to ity progression [ 1 ] . Another consequence of the one of the experimental arms, rather than great expense of RCTs is that new drugs tend to choosing one of the arms or being assigned be very expensive. Despite the above negatives, by a study physician. the MS community sees RCTs as a major advance (b) They are double-blinded. Neither the in developing new therapies for MS. patient nor the study physicians know which arm of the study the patient has been randomized to. Occasionally, the 1.2 The Primary Endpoint term triple-blind is used for some studies in which an additional layer of individuals The disadvantages of RCTs, primarily their expense in the study is masked as to the treatment and length, are outweighed by their scientifi c rigor groups. For instance, some clinical trials in establishing a reliable answer to the question: specialists recommend that statisticians does this drug work in MS? But, as is the usual in analyzing data be blinded, since potential clinical issues, the devil is in the details. What does bias can be present in the analysis of the the word “work” mean; in other words, what aspect study. of MS responds in a positive way to the therapy? (c) They are placebo-controlled . At least one All RCTs must have a primary endpoint, a single of the arms involves treatment with a pla- measure of the disease in which the MS population cebo, an agent that is not biologically active being treated with the drug is compared to either a and has no effect on the disease process. placebo-treated population or an active compara- More recently, with the advent of a number tor. This must be a measure which can be reduced of partially effective agents, more RCTs to a number. This requirement for a primary end- are beginning to be active comparator- point is due to the need, prior to study recruitment, controlled, rather than placebo-controlled. to identify the number and kind of patients An active comparator is an agent that is required, and the needed time in the study. 1 Disease-Modifying Drugs 71 Pharmaceutical companies formulate the primary with DMDs as soon as possible in patients with endpoint according to what will allow their product MS or with a clinical presentation highly likely to to be approved by regulatory agencies such as the develop into MS. FDA in the USA and EMEA in Europe, not accord- ing to what neurologists, patients, patient fami- lies, radiologists, or pathologists consider to be 1.4 General Approach to Therapy most important in the disease. As discussed briefl y in Chap. 4 , identifying a single aspect of MS to 1. The goal of current therapies is the reduction focus on is fraught with conceptual peril. Up to of relapses or gadolinium-enhanced lesions on now, the disease-modifying agents have been MRI, which is hoped to result in delayed or approved generally on the basis of trials demon- reduced disability. strating a reduction in relapse rate. Many neurolo- As mentioned above, the primary endpoint for gists feel that future drugs should demonstrate most studies demonstrating effi cacy of MS drugs effi cacy in reducing disability progression to has been reduction in relapses. One of the “plat- achieve approval, since our armamentarium for form drugs,” as discussed below, is thus indicated treating relapse frequency is now reasonably ade- for patients with relapses, especially when the quate. However, there is no consensus about how to relapses are frequent. However, it is not a given measure disability as a primary endpoint in a drug that a medication that will lower relapse frequency trial. This is because of the slow accrual of disabil- will also defi nitively slow disease progression. ity over time in most MS patients and the inher- In a study of 1,844 MS patients, Confavreux et al. ent problems with disability measurements in came to the following conclusions. short-term studies. We found that once a clinical threshold of irrevers- ible disability has been reached (a score of 4 on the Kurtzke Disability Status Scale), the progression of disability is not affected by relapses, either those that 1.3 When Should One Treat occur before the onset of the progressive phase or those that supervene during this phase. The absence with DMDs? of a relation between relapses and irreversible dis- ability suggests that there is a dissociation at the bio- The pivotal studies of the DMDs in the 1990s logic level between recurrent acute focal infl ammation and progressive degeneration of the central nervous were performed in patients who had clinically system. This apparent paradox is consistent with the defi nite MS, often for at least a year. When these persistence of the progression of disability in patients agents were shown to be effective in this popula- with multiple sclerosis despite infection with the tion, subsequent studies were performed in CIS human immunodefi ciency virus or despite suppres- sion of the cerebral infl ammation after treatment patients to see if DMDs could ameliorate the with a potent antileukocyte monoclonal antibody. It course of the disease when administered earlier also suggests that agents that have a short-term effect in the disease. The fi rst such study was the on relapses in patients with multiple sclerosis may CHAMPS study, in

which Jacobs et al. demon- not necessarily delay the development of disability in the long term. [4 ] strated that, in patients with CIS and at least two brain MRI lesions typical of MS (a population Their fi ndings were confi rmed in a more recent highly likely to develop clinically defi nite MS) large study by Scalfari et al. [5 ] utilizing the 35% of those treated with intramuscular IFN- Sylvia Lawry database. Their conclusion was b- 1a developed CDMS, while in the placebo that neither total number of attacks nor attacks group, 50% developed CDMS [3 ] . This differ- experienced after the second year of the disease ence was highly signifi cant and led to the wide- correlated with disability progression. It is thus spread use of DMDs in patients with CIS and our hope rather than a proven fact that available brain MRI lesions typical of MS. Subsequent therapies for MS, especially when started early in studies with IFN-b -1b and GA have confi rmed the disease course, are effective in delaying or these results. Thus, most neurologists now treat suppressing disability progression. 72 7 Multiple Sclerosis Therapy 1.5 Current Agents When MRI became increasingly used for MS diagnosis, it became clear that MS was not just a 1.5.1 Corticosteroids disease of clinical attacks with normalcy in The most commonly used corticosteroid for acute between attacks, but rather a constantly present attacks of MS is methylprednisolone, also called disease in which lesions were continually accrued, Solumedrol. This compound has a molecular most of which occurred subclinically. IFN- b is a weight of 374 Da and is a typical corticosteroid treatment which is used continually even in the with a structure derived from cholesterol with mul- absence of attacks. tiple sites of hydroxylation. Corticosteroids are An extended history of the development of used by neurologists to treat an ever increasing list IFN-b is beyond the scope of this primer. The of diseases. They are generally safe over the short drug was initially used intrathecally on the theory term. However, large doses, especially given over that MS was a viral infection and might respond an extended time period, can cause many adverse to IFN- b , which has strong antiviral effects. Later, effects, including elevated blood sugars and diabe- the route of administration was switched to sys- tes, decreased bone density (osteoporosis), psychi- temic injection, i.e., subcutaneous or intramuscu- atric complications (including anxiety, depression, lar. IFN- b is in a class of proteins called and sleeping disorders), hypertension, and cata- interferons, of which there are many different racts. For this reason, the chronic use of corticoster- forms in human. The most commonly studied oids at high doses is not considered an acceptable interferons are labeled IFN-a , - b , and - g . IFN- b therapy for MS. Instead, corticosteroids are gen- is a glycoprotein of approximately 20,000– erally used to treat attacks, at which time they are 22,000 Da in size and is considered a biological administered at high dose intravenously or orally therapy; like most biological therapies, is pro- for a short time period, usually just 3–5 days. duced by recombinant technology. There are cur- One of the fi rst randomized, clinical trials related rently four preparations of IFN-b available in the to MS was testing of corticosteroid therapy for USA and Europe which can be divided into IFN- optic neuritis, called the Optic Neuritis Treatment b -1a or IFN-b -1b; these differences are briefl y Trial (ONTT) [6 ] . The entry criteria required rela- summarized in the accompanying table (Fig. 7 .1 ). tively severe optic neuritis with both an afferent The IFN-b -1a products are made in genetically pupillary defect (APD) and a visual fi eld defect, engineered Chinese hamster ovary (CHO) cells, but did not require the presence of MS, and excluded have the same amino acid structure as does human patients with already known MS. The study found IFN-1b , and are glycosylated, while the IFN- that intravenous treatment with one gram of meth- b -1b products are made in the bacterium E . coli , ylprednisolone (Solu-Medrol), per day for 3 days have one amino acid difference from natural accelerated visual recovery but did not improve IFN-b -1, and are not glycosylated. visual outcome after 1 year. The study also found The mechanism of action of all of the IFN-b that just the one treatment with IV Solumedrol preparations is binding to the interferon a – b therapy delayed the development of MS relative to receptor (IFNAR) leading to the upregulation or untreated individuals. This multicenter study laid downregulation of a hundreds of genes, as shown the groundwork for many of the large RCTs of in Fig. 7.2 . Many cells in the body have IFNARs other agents for MS in the subsequent decades. and are thus susceptible to the IFN-b effects, but the specifi c target cell types and the up- or down- 1.5.2 First-Line Disease-Modifying regulated genes responsible for the drug’s effect Drugs in MS in MS are unknown. Many of the genes regulated Interferon-b (Brand Names: Avonex, by IFN-b have roles in innate immunity and pro- Betaseron, Rebif, Extavia) tect cells against destruction during a viral attack. How does IFN-b work in MS? We haven’t got a An example of such a gene is the Mx1 gene, the clue. protein product of which has been used exten- M ark Freedman, University of Ottawa, Ottawa, sively for detecting IFN- b bioactivity in IFN- b - Canada, 2010 treated MS patients [7 ] . IFNAR activation is 1 Disease-Modifying Drugs 73 Fig. 7.1 Types of interferon- b currently available for therapy of MS. Recently, Extavia, an IFN-b -1b product has been made available. This drug is identical to Betaseron, the drug in the fi rst column of the table Fig. 7.2 IFN-b signal transduction. IFN- b , shown as IFN- a . After binding of IFN- b to the receptor, there is “ b ” in this cartoon, works by binding to a specifi c recep- an orderly sequence of intracellular events including tor on the cell surface, shown as the “Type 1 IFN recep- activation of kinases and transcription factors, and after tor complex,” but also known as the interferon- a / b hours upregulation of mRNAs for a host of IFN- receptor or IFNAR. This receptor binds either IFN-b or upregulated genes 74 7 Multiple Sclerosis Therapy required for IFN-b effect, and MxA and other low-grade liver injury, which is rapidly reversible IFN- b -inducible genes can serve as biomarkers upon discontinuation of the medication. The drug of this effect. should not be injected during pregnancy. Skin reactions occur relatively frequently with subcu- Therapeutic Effect taneous preparations, but these are usually not Multiple studies have demonstrated that IFN-b severe enough to require discontinuation of drug. has at least two salutary effects in MS: a decrease Mild decreases of the concentration of white in attack frequency and a decrease in the occur- blood cells is the peripheral blood are common, rence of gadolinium-enhancing lesions. These but almost never a cause for stopping the drug. effects are most obvious in the fi rst year of ther- apy but less obvious after that. These drugs along Other Issues Affecting Use of IFN-b with glatiramer acetate (see below) have become in MS the standard of care for MS therapy. However, – Anti-IFN-b antibodies . IFNAR activation, some investigators, using careful analysis of the which is the pathway by which the drug, is multiple clinical trials, have called into question compromised in some patients by anti-IFN-b the magnitude of the effect: “Recombinant inter- antibodies, which bind to circulating IFN-b ferons slightly reduce the number of patients who after injection and prevent its binding to IFNAR . have exacerbations during fi rst year of treatment. Because IFN-b is injected at frequent intervals, Their clinical effect beyond 1 year is uncertain ranging from every other day to weekly, the and new trials are needed to assess their long- injections serve as a nearly constant antigenic term effectiveness and side-effects [8 ] .” challenge, and antibodies, when they develop, The effect of IFN-b on disability progression usually begin to increase during the fi rst over an extended period of time has not been months of therapy. These antibodies can block carefully studied. In most MS patients, disability the effects [9 ] and diminish the therapeutic accrues slowly, so that the usual phase 3 studies effi cacy [1 0 ] . Although therapeutic IFN-b is lasting 2 years or less will not detect signifi cant manufactured by pharmaceutical companies to differences in disability between treated and pla- resemble human IFN-b as closely as possible cebo groups, even if an ameliorative effect is to minimize its immunogenicity, all of the cur- present. One of the problems with these short rent preparations have differences from human studies is that patients accrue temporary disabil- natural IFN-b which the human immune system ity from attacks, which sometimes lasts many can discern. Two different assays can be used months. Consequently, in a short study, a salutary to measure anti-IFN-b antibodies in IFN-b - effect on relapse frequency may be manifested in treated patients. The fi rst is a fast, inexpensive an effect on relapse-induced disability, but this enzyme-linked immunosorbent assay (ELISA) effect may be quite transient. Most clinicians are which measures all antibodies in the human hopeful that over the long term decreased relapses serum which bind to IFN-b . If this assay is and decreased gad-enhancing lesions will trans- positive, a neutralizing antibody (NAb) assay late into less disability. is performed, in which the ability of antibody to block IFN-b binding to IFNAR is tested Side Effects in vitro. These antibodies do not occur in IFN- b is well tolerated by most patients. The untreated individuals. most common problem, usually felt mostly in the – Cost . IFN-b is an expensive agent, with costs fi rst few months of therapy, is “fl u-like symp- in the USA usually being between 20,000 and toms.” Within a few hours after the injection, 30,000 dollars per patient per year. This has many patients experience malaise, muscle and led to a call for generic IFN-b products which joint aches, low-grade fever, and increased would be much less expensive. However, qual- fatigue. Other patients never develop these symp- ity control is a major concern for generic toms. A very low percentage of patients develop biologics, in general, and generic IFN-b 1 Disease-Modifying Drugs 75 preparations would need to demonstrate anti-GA antibodies [1 3 ] in GA-treated patients. comparable high potency and low Unlike IFN- b , which operates by binding to a immunogenicity. well-characterized membrane receptor thereby – Adherence to therapy . The fact that IFN- b regulating a large number of genes, and thus can needs to be administered by injection between be followed by a number of biomarkers, GA has every other day to once a week, with usually no receptor or consistently upregulated genes or no change in the disease perceptible to the biomarkers. patient, has resulted in less than optimal com- pliance with these drugs. The pharmaceutical Therapeutic Effect companies making these products have MS patients who injected glatiramer in pivotal attempted with variable success to address this phase 3 studies experienced fewer relapses and issue, but studies have demonstrated that many developed fewer gadolinium-enhanced lesions on and possibly most patients are not fully adher- brain MRI than those who injected placebo. As in ent to the injection protocols. It is theoretically therapy with IFN- b , an effect of therapy on dis- possible to assess this by measuring IFN-b - ability progression has not been proven. upregulated biomarkers in blood, such as the MxA protein [1 1 ] , but these assays are not routinely available for clinical use. Side Effects GA is usually well-tolerated. Rarely, patients can Glatiramer Acetate (GA) get a reaction within ½ h after injection consist- GA was initially developed at the Weizmann ing of fl ushing, shortness of breath, palpitations, Institute in Israel to be used as an aid to research- and chest tightness. Other patients can develop ers in the induction of experimental autoimmune pitting of skin at sites of injection due to the loss encephalomyelitis (EAE), an experimental model of

fat called lipoatrophy. The incidence of lipoat- of post-vaccinial encephalomyelitis sometimes rophy is unclear from the literature, ranging from used as a model of MS (see Chap. 8 ). Although it rare to nearly 50% of patients. was unable to induce EAE, it was found to inter- fere with the induction of EAE [1 2 ] . The basis for Other Issues the biological activity of GA was felt to be its – Anti-GA antibodies . Daily subcutaneous injec- immunological cross reactivity with myelin basic tion with GA induces anti-GA antibodies in protein (MBP), the “encephalitogen” in those nearly all patients. However, because there is experiments. GA is a synthetic random copoly- no receptor or biomarker for GA, neutralizing mer of l -alanine, l -glutamic acid, l -lysine, and antibody assays cannot be performed. The l -tyrosine in a residue molar ratio of requirement for an NAb assay is that the treat- 6.0:1.9:4.7:1.0. ment must induce a reproducible, measurable For the treatment of MS, 20 mg of GA is in vitro effect which could then be abolished injected subcutaneously daily. The mechanism of by NAbs, and such an in vitro effect has not action of GA in MS is unknown and although it yet been found for GA. Unlike the situation in was developed as a congener for MBP to sup- IFN-b therapy, in which anti-IFN- b antibodies press anti-MBP-mediated autoimmunity, there is interfere with the therapeutic effect, anti-GA no evidence for anti-MBP autoimmunity in MS. antibodies are felt to have no adverse effects Many mechanisms have been postulated, but and were actually found at higher levels in none have been able to be broadly reproduced or relapse-free patients [1 4 ] . utilized for monitoring therapy in practice. Some – Cost . GA’s expense, like that of IFN-b , is high. of its effects may be due to the large protein chal- – Adherence to therapy . As with IFN-b , adher- lenge injected subcutaneously every day, which ence to therapy is not optimal. With GA treatment may generate a constant immunological chal- requiring daily injections, most GA-treated lenge; this hypothesis is supported by persistent patients are not fully adherent to therapy as 76 7 Multiple Sclerosis Therapy Fig. 7.3 Migration of a lymphocyte out of the blood- cells, the lymphocyte rapidly activates a stronger adhesion stream into a lymph node. A circulating lymphocyte system, mediated by an integrin. This strong adhesion adheres weakly to the surface of the specialized endothe- enables the cell to stop rolling and migrate out of the lial cells lining a postcapillary venule in a lymph node. venule between the endothelial cells. The subsequent This initial adhesion is mediated by l -selectin on the lym- migration of the lymphocytes in the lymph node also phocyte surface. The adhesion is suffi ciently weak to depends on chemokines, which are produced within the enable the lymphocyte to roll along the surface of the node. The migration of other white blood cells out of the endothelial cells, pushed along by the fl ow of blood. bloodstream into sites of infection occurs in a similar Stimulated by chemokines secreted by the endothelial way prescribed. It is unclear how strictly adherent Natalizumab (Brand Name: Tysabri) patients must be to receive benefit from Natalizumab is the fi rst therapeutic monoclonal the drug. antibody demonstrated to be effective in MS. Natalizumab is a humanized neutralizing IgG4 kappa monoclonal antibody against a 4 integrins 1.5.3 Second-Line Drugs (see Sect. 2.2.5 of Chap. 1 for a brief introduction These drugs are usually used in the USA when to adhesion molecules). a 4 b 1 integrin, a het- the platform drugs have proven ineffective. The erodimer (composed of an alpha and a beta particular conditions that defi ne “ineffective” chain), is also occasionally referred to as “very will be highly variable from patient to patient late antigen-4 (VLA-4),” since it is expressed and from neurologist to neurologist. These drugs relatively late in the infl ammatory response. Cells are considered second level, not fi rst line, bearing a 4 b 1 integrin can bind to another cell because there are known serious adverse events adhesion molecule called VCAM-1, also known (SAEs) (e.g., natalizumab or mitoxantrone) or as CD106, which is expressed on endothelial cell because the drugs have not been clearly demon- membranes only after exposure to cytokines. strated to be effective in a RCT (e.g., immuno- As an anti- a 4 integrin antibody, natalizumab also suppressives such as methotrexate or targets cells which have a 4 b 7, a molecule essen- cyclophosphamide). In Europe, many drugs tial for mononuclear cell infl ux into the small which are felt to be second line in the USA, such intestine. Integrins are felt to be critical to allow as azathioprine, have been popular as fi rst-line white cells to enter tissues from the circulation. agents [1 5 ] . A head-to-head study of azathio- This involves a progressive slowing of the veloc- prine vs. IFN-b has been recently proposed [1 6 ] . ity of the cell, followed by rolling, and then adhe- The lack of a clearly optimal treatment protocol sion and migration, as shown in Fig. 7.3 . The is a testament to the lack of full effi cacy of any ability of natalizumab to interfere with leukocyte one agent or combination of agents. entry into the CNS by binding to and blocking 1 Disease-Modifying Drugs 77 a 4 b 1 integrin on the surface of leukocytes is Mitoxantrone (Novantrone) what is thought to mediate its salutary effects in Mitoxantrone, which was previously used MS [1 7 ] . However, a 4 integrin is a molecule primarily as an anticancer drug, was approved by present throughout the immune system, and other the FDA in the USA in 2000 for the treatment of mechanisms, either in addition to or instead of worsening relapsing–remitting, secondary pro- CNS entry, are equally plausible. Thus, the pre- gressive, and progressive relapsing MS, based on cise mechanisms for its effects in MS are not the Mitoxantrone in MS (MIMS) study [1 8 ] . Like known. Because of the relatively long half life of natalizumb, it is also considered to be an agent IgG4, natalizumab is infused once per month. not to be used as a platform drug in patients with The current product insert for the drug, which newly diagnosed relapsing–remitting MS. It has is an FDA-regulated summary of usage, states a demonstrated effect in an underserved popula- that “Tysabri is generally recommended for tion of MS patients, those with more severe dis- patients that have not been helped enough by, or ease or who are progressing in disability [1 9 ] . cannot tolerate, another treatment for MS.” That Mitoxantrone is an anthracenedione compound is, Tysabri is recommended as a second-line agent that interferes with DNA synthesis and is primarily after the use of one of the platform drugs. The used as an antineoplastic agent. It also is immuno- reason is the occurrence of a SAE. After initially suppressive, affecting almost all mononuclear cells being available in November, 2004, natalizumab including T cells, B cells, and macrophages. Adverse was pulled from the marketplace in February, effects initially were thought to be primarily related 2005, only 3 months later, because three partici- to its cardiotoxicity which could be avoided by care- pants in clinical trials of the drug developed pro- ful noninvasive cardiac monitoring by echocardiog- gressive multifocal leukoencephalopathy (PML), raphy. However, recently increasing reports of a dangerous and frequently fatal viral CNS infec- treatment-related acute leukemias (TRAL) in MS tion. Since then, natalizumab has been reintro- patients treated with mitoxantrone have led to duced into the marketplace with a number of more concern about the risk–benefi t ratio for mitox- precautions. The judgment of the FDA was that antrone. A recent report by a Therapeutics and the drug was very effective in MS and could be Technology Assessment Subcommittee of the used as a second-line agent. This hypothesis is American Academy of Neurology concluded that currently being tested in the SURPASS study, “clinicians contemplating MX administration for an which will test the performance of Tysabri against individual patient with MS must weigh the poten- IFN- b or glatiramer. The development of PML is tial for benefi t against the potential for harm given a rare side effect of a number of immunosuppres- the (approximately) 12% risk of systolic dysfunc- sive medications, as well as being a not uncom- tion and (approximately) 0.8%risk of TRAL and mon manifestation of severe immunosuppression the availability of alternative therapies with less in HIV-AIDS. PML will be discussed at greater severe toxicities (e.g., IFN-b and glatiramer ace- length in Chap. 12 . A serum anti-JC virus anti- tate) for patients with RRMS” [2 0 ] . body assay to test for previous exposure to the JC virus has recently become available to clinicians 1.5.4 Old Drugs for MS to assess the risk of PML in a patient. Patients Immunosuppressives who are seronegative are at less risk for PML Azathioprine (Imuran), cyclophosphamide than patients who are seropositive; studies on this (Cytoxan), and methotrexate (Rheumatrex) are anti-JC virus antibody assay are ongoing. drugs used as immunosuppressives in MS and are Another problem in natalizumab therapy of discussed in Chap. 19 . MS is neutralizing antibodies to the therapy which result in the loss of effi cacy. This is less of a prob- Controversies lem for this therapy, in contrast to IFN-b , and is The use of immunosuppressives in MS is contro- found in only 6% of recipients of the drug. versial. Azathioprine is considered a relatively 78 7 Multiple Sclerosis Therapy Fig. 7.4 Drawing of chemical structure of fi ngolimod (Wikimedia, public domain at http://commons.wikimedia.org/ wiki/File:Fingolimod.png ) safe immunosuppressive drug in Europe and is Cladribine commonly used there. A recent large meta-analysis This drug is a small purine analog (molecular of the use of azathioprine in MS comes to a weight of 286) which resembles adenosine and favorable conclusion and recommends a com- inhibits adenosine deaminase. It has been used parison study of IFN- b with azathioprine [ 16 ] . In for the last 20 years in the treatment of hairy cell some MS practices, the more potent cyclophos- leukemia and is considered an immunosuppres- phamide at moderate doses is used extensively as sive agent. Positive treatment results in MS were a platform drug, while in most MS centers, it is reported in the early 2010 [2 2 ] . An oral treatment used rarely, and only in patients with highly protocol in the phase 3 study results in prolonged infl ammatory presentations. Two trials published leukopenia. Three to four percent of patients in the early 1990s came to different conclusions: developed shingles (reactivated herpes zoster) results from the Northeast Cooperative Multiple and one patient died of reactivated latent tubercu- Sclerosis Treatment Group was supportive of its losis. Otherwise the drug appeared to be well- use, while a Canadian study found no signifi cant tolerated. between-group differences in time to treatment failure. Various aspects of the controversies over 1.5.6 Combination Therapies the use of immunosuppressive agents in MS are Not only is the pathogenesis of MS complex but summarized in a recent review article [2 1 ] . also factors contributing to disease may vary among patients. This would suggest that combi- 1.5.5 New Drugs for MS nation therapy strategies might be effective. Thus, Two oral medications have demonstrated signifi - some clinicians will initially use the DMDs, and cant benefi t in reducing relapses in large phase III add to this corticosteroids, azathioprine, natali- studies: fi ngolimod was approved in September zumab, cyclophosphamide, or methotrexate. 2010, and cladribine was submitted to the FDA Although combination therapies are frequently for approval for use in MS, but further safety used in practice, they have not been demonstrated studies were requested. to be effective in large clinical studies [2 3 ] . Fingolimod Fingolimod is a relatively small lipophilic chemi- 2 Symptomatic Therapies cal (Fig. 7.4 ) derived from fungi, related to the myriocins, which have antibiotic properties. The A neurologist caring for MS patients treats not fungus source, I saria sinclairii , has been used as only the disease itself but also a variety of symp- a Chinese herbal remedy for centuries. The

drug toms caused by the CNS damage. The most com- is thought to work by interfering with sphin- mon symptoms are fatigue, bladder and bowel gosine-1-phosphate (S1P) binding to its receptors dysfunction, spasticity, cognitive problems, in lymph nodes further discussed in Chap. 19 . depression, and sexual problems. There are two 2 Symptomatic Therapies 79 categories of approach to therapy: life-style changes and rehabilitation, and medications. This topic has been recently reviewed in depth [2 4 ] . (a) Rehabilitation . Rehabilitation medicine has proven extremely helpful to MS patients and should be utilized extensively. Although tra- ditionally treating patients with gait diffi culty, rehabilitation medicine physicians and physi- cal therapists have broadened their scope to Fig. 7.5 Chemical structure of baclofen provide a range of other services to MS patients. which use GABA as an inhibitory neurotransmitter. (b) Life-style changes . In early MS, when dis- Many GABA-ergic interneurons also used a ability is mild, patients can usually pursue variety of other neurotransmitter such as opiate their lives with little attention to the disease. peptides, cholecystokinin, and somatostatin. But when disability begins to develop, cer- GABA-ergic interneurons in the spinal cord also tain life-style changes can be very effective. frequently use glycine as a neurotransmitter. For instance, rest during the day and careful The structure of baclofen is interesting; it is a attention to improving sleep can help fatigue. small molecule (molecular weight of 214), com- Bladder symptoms can be improved by cut- posed of two enantiomers, mirror images of each ting back on commonly ingested diuretics other, in a 1:1 ratio (Fig. 7 .5 ). It is considered a such as caffeine. GABA agonist, and in this way substitutes for the (c) Medications . A wide range of medications GABA produced in the spinal cord by inhibitory can be effective for MS symptoms. However, interneurons. The GABA receptors are located in many of these medications have signifi cant the presynaptic terminals of the Ia fi bers, binding side effects and a careful risk/benefi t analysis of GABA or baclofen to these receptors inhibits must be performed with each patient. For calcium infl ux and lowers the amount of trans- instance, anti-spasticity medications such as mitter released. baclofen and tizanidine can cause a general- Patients with progressive MS can develop ized lowering of muscle tone which can inter- spasticity in their arms and hands which can fere with gait; they also frequently increase sometimes be relieved by local injections of bot- fatigue. ulinum toxin (Inset 7 .1 ). Botulinum toxin can Spasticity, the increased muscle and tendon also be injected into the detrusor muscle of the tone, and stiffness of movement of weak muscles bladder which can improve bladder symptoms in associated with CNS damage, can be disabling to some MS patients. Bladder issues are especially patients with MS and other diseases which result common in MS, and, depending on their cause in CNS injury. Four different classes of agents can be improved with anticholinergics or antibi- are used to decrease spasticity in multiple sclero- otics for urinary infections. An increasingly help- sis: (a) GABA agonists (e.g., baclofen), (b) a -2 ful referral for some patients is to neuro-urologists, adrenergic agonists (e.g., tizanidine), (c) periph- who can provide the latest and best diagnosis and eral anti-spastics (e.g., dantrolene), and (d) botu- treatments for MS patients with diffi cult-to-man- linum toxin injected locally to decrease spasticity. age bladder control problems. Of these the most widely prescribed medication A medication that has recently been approved for spasticity in MS is baclofen (brand name in as a symptomatic medication for improving the the USA: Lioresal). The rationale for the use of gait of patients with MS is 4-aminopyridine baclofen is as follows: neurons of the cerebral (Ampyra), also called dalfampridine or fampri- cortex have been classifi ed into projection neu- dine. Historically, 4-AP has been used in the rons, which primarily use glutamate as an excit- research laboratory to characterize various forms atory neurotransmitter, and local interneurons, of the potassium channel, since it is a relatively 80 7 Multiple Sclerosis Therapy currents with 4-AP can reverse this effect, and the Inset 7.1 Botulinum Toxin drug has been used in MS and the Lambert–Eaton T he word botulinum comes from the Latin myasthenic syndrome (see Chap. 9 ) . The action of word for sausage, botulus, since in the this drug, however, may not be so simply explained, nineteenth century botulism, i.e., poisoning since recent studies have shown that 4-AP also with botulinum toxin, was most commonly has effects on the calcium channel. seen in its food-borne form, from improp- erly handled meats as ingredients for sau- sages. The toxin is produced by the References anaerobic bacterium C lostridium botuli- num , a Gram-positive rod; the pathogen 1. Ebers GC, Heigenhauser L, Daumer M, Lederer C, Noseworthy JH. Disability as an outcome in MS clini- was fi rst isolated by Emile van Ermengem, cal trials. Neurology. 2008;71(9):624–31. a Belgian bacteriologist in 1896 from a 2. Cohen JA, Barkhof F, Comi G, et al. Oral fi ngolimod cured ham identifi ed as the cause of a botu- or intramuscular interferon for relapsing multiple lism outbreak. sclerosis. N Engl J Med. 2010;362(5):402–15. 3. Jacobs LD, Beck RW, Simon JH, et al. Intramuscular Botulinum toxin is a large protein (molec- interferon beta-1a therapy initiated during a fi rst ular weight of 150,000) made up of two demyelinating event in multiple sclerosis. CHAMPS chains, one of which is a protease that acts Study Group. N Engl J Med. 2000;343(13):898–904. on a fusion protein at the presynaptic termi- 4. Confavreux C, Vukusic S, Moreau T, Adeleine P. Relapses and progression of disability in multiple nal of the neuromuscular junction to inhibit sclerosis. N Engl J Med. 2000;343(20):1430–8. acetylcholine release (the neuromuscular 5. Scalfari A, Neuhaus A, Degenhardt A, et al. The natu- junction as an important “Achilles heel” in ral history of multiple sclerosis, a geographically neuroimmunology is discussed in Chap. 10 based study 10: relapses and long-term disability. Brain. 2010;133(Pt 7):1914–29. on myasthenia gravis). The lethal dose for 6. Beck RW, Cleary PA, Anderson Jr MM, et al. A ran- inhaled botulinum toxin is about 3 ng/kg. domized, controlled trial of corticosteroids in the Botulinum toxin poisoning is important treatment of acute optic neuritis. The Optic Neuritis to neurologists as a cause of rapidly progres- Study Group. N Engl J Med. 1992;326(9):581–8. 7. Pachner AR, Warth JD, Pace A, Goelz S. Effect of sive paralysis, and as an important differen- neutralizing antibodies on biomarker responses to tial diagnosis in patients with Guillain–Barré interferon beta: the INSIGHT study. Neurology. syndrome (see Chap. 9 ). Botulinum toxin is 2009;73(18):1493–500. available commercially for therapeutic 8. Filippini G, Munari L, Incorvaia B, et al. Interferons in relapsing remitting multiple sclerosis: a systematic purposes which is especially important to review. Lancet. 2003;361(9357):545–52. neurologists as an aid in the treatment of 9. Pachner AR. An improved ELISA for screening for spasticity, especially when a muscle or small neutralizing anti-IFN-beta antibodies in MS patients. group of muscles can be targeted. Many Neurology. 2003;61(10):1444–6. 10. Pachner AR, Steiner I. The multiple sclerosis severity patients with chronic myelopathies, includ- score (MSSS) predicts disease severity over time. ing MS, have clenched hands that can be J Neurol Sci. 2009;278(1–2):66–70. loosened up by botulinism toxin injections. 11. Pachner AR, Dail D, Pak E, Narayan K. The impor- Other uses of botulinum toxin are cosmetic tance of measuring IFNbeta bioactivity: monitoring in MS patients and the effect of anti-IFNbeta antibodies. or military, as part of many countries’ arse- J Neuroimmunol. 2005;166(1–2):180–8. nal of biological weapons. 12. Teitelbaum D, Meshorer A, Hirshfeld T, Arnon R, Sela M. Suppression of experimental allergic enceph- alomyelitis by a synthetic polypeptide. Eur J Immunol. 1971;1(4):242–8. selective blocker of a family of voltage-gated 13. Karussis D, Teitelbaum D, Sicsic C, Brenner T. Long- potassium channels. In MS, there are theoretically term treatment of multiple sclerosis with glatiramer acetate: natural history of the subtypes of anti-glatiramer augmented potassium currents which ultimately acetate antibodies and their correlation with clinical can lead to conduction failure. Blocking potassium effi cacy. J Neuroimmunol. 2010;220(1–2):125–30. References 81 14. Brenner T, Arnon R, Sela M, et al. Humoral and cel- double-blind, randomised, multicentre trial. Lancet. lular immune responses to Copolymer 1 in multiple 2002;360(9350):2018–25. sclerosis patients treated with Copaxone. J Neuro- 20. Marriott JJ, Miyasaki JM, Gronseth G, O’Connor PW. immunol. 2001;115(1–2):152–60. Evidence Report: The effi cacy and safety of mitoxan- 15. Rubio-Terres C, Dominguez-Gil Hurle A. [Cost- trone (Novantrone) in the treatment of multiple scle- utility analysis of relapsing-remitting multiple sclero- rosis: report of the Therapeutics and Technology sis treatment with azathioprine or interferon beta in Assessment Subcommittee of the American Academy Spain]. Rev Neurol. 2005;40(12):705–10. of Neurology. Neurology. 2010;74(18):1463–70. 16. Casetta I, Iuliano G, Filippini G. Azathioprine for 21. Boster A, Edan G, Frohman E, et al. Intense immuno- multiple sclerosis. Cochrane Database Syst Rev. 2007; suppression in patients with rapidly worsening multiple (4):CD003982. sclerosis: treatment guidelines for the clinician. 17. Ransohoff RM. Natalizumab for multiple sclerosis. N Lancet Neurol. 2008;7(2):173–83. Engl J Med. 2007;356(25):2622–9. 22. Giovannoni G, Comi G, Cook S, et al. A placebo- 18. Edan G, Miller D, Clanet M, et al. Therapeutic effect controlled trial of oral cladribine for relapsing multiple of mitoxantrone combined with methylprednisolone sclerosis. N Engl J Med. 2010;362(5):416–26. in multiple sclerosis: a randomised multicentre study 23. Conway D, Cohen JA. Combination therapy in multiple of active disease using MRI and clinical criteria. sclerosis. Lancet Neurol. 2010;9(3):299–308. J Neurol Neurosurg Psychiatry. 1997;62(2):112–8. 24. Kesselring J, Beer S. Symptomatic therapy and neu- 19. Hartung HP, Gonsette R, Konig N, et al. Mitoxantrone rorehabilitation in multiple sclerosis. Lancet Neurol. in progressive multiple sclerosis: a placebo-controlled, 2005;4(10):643–52. Experimental Models of MS 8 Multiple sclerosis is a uniquely human disease. within the CNS. Specifi c models can focus on It does not occur naturally in any other animal, only a few of these aspects of MS at a time, but and, in fact, no other disease closely resembling none reproduces the whole spectrum of the dis- MS has been described in other animals. Similarly, ease. Third, the ideal use of an animal model is to no animal models of MS mimic all of the features provide information about basic biological pro- of the human disease faithfully. However, animal cesses within the CNS with some relevance to models of MS are important because they allow MS, but increasingly there is pressure from us to learn about neuroinfl ammation, and its link patients and funding agencies to translate work in to demyelination, neuronal injury, and disability. animal models to human disease too rapidly. The two main types of models—autoimmune and Despite these and other problems, the use of ani- viral—also teach us about the effects of these mal models for MS has continued to be used processes within the CNS. We learn something extensively, and indeed provides the most com- from each model, and it is important to assess mon research focus within neuroimmunology. information obtained from each one as contribut- ing to our knowledge base, rather than having direct translation to the human disease. This point 1 Animal Models of MS is frequently lost on individuals who wish to rush preliminary information about models directly to 1.1 Autoimmune MS treatments. This eagerness is understandable in MS patients, who are desperate for more effec- “EAE, the autoimmunity-based animal model, is tive therapies. But clinicians and scientists must not seen as inherently superior to (viral) models take the long view, and place new information in like Visna or TMEV…One might be right to regard context of the strengths and weaknesses of each autoimmunity as a paradigm shift that never quite made it!” Byron H. Waksman [1 ] model. There are many problems with modeling MS. Under certain conditions provoking an auto- First, the etiopathogenesis of the human disease immune response in the CNS, animals can is unknown. The two main types of models, auto- develop infl ammation, demyelination, and immunity and virus, are based on reasonable weakness. The fi rst demonstration that the hypotheses, but there is no strong evidence that immune response in presumably healthy indi- MS is due to either an autoimmune or a viral pro- viduals could injure the CNS came when cess and in

fact, there is no assurance that the humans, injected with rabies vaccines contain- underlying cause is the same in all patients. ing CNS material to prevent rabies infections, Second, MS is multifaceted, involving attacks, developed post-vaccinial encephalomyelitis, progressive disability, demyelination, infl amma- reviewed in Chap. 3 . In 1925, Koritschoner and tion, and excessive immunoglobulin production Scweinburg induced infl ammation in rabbit A.R. Pachner, A Primer of Neuroimmunological Disease, 83 DOI 10.1007/978-1-4614-2188-7_8, © Springer Science+Business Media, LLC 2012 84 8 Experimental Models of MS spinal cord by immunization with human spinal which make it more susceptible than other strains. cord [ 2 ] ; soon thereafter, Rivers et al. published In MOG-induced EAE, a different mouse strain, a report of their work on reproducing systemati- C57Bl/6, is more susceptible. Most investigators cally this syndrome in monkeys, also called utilize active immunization of the encephalitogen acute disseminated encephalomyelitis (ADEM), combined with an adjuvant, usually Freund’s adju- by immunization with CNS tissue [3 ] . Since vant, a mixture of oil and other constituents, then, experimental autoimmune encephalomy- including heat-killed mycobacteria, that enhances elitis (EAE) has been induced in many different the immune response to the encephalitogen, pos- experimental animals by immunization with any sibly by the stimulation of toll-like receptors one of several different CNS antigens. Although (TLRs) . In addition, most murine EAE models initially EAE was developed to model ADEM, require the injection of a bacterial toxin, pertussis the combination of infl ammation and demyeli- toxin (see Inset 8 .1 ), which is thought to enhance nation led investigators to recognize that it also EAE by increasing blood–brain barrier permeabil- mimic features of MS. ity or by activating TLRs. CNS tissue, or purifi ed parts of it, that can induce EAE are called encephalitogens. Initial work on EAE was focused on determining the composition of encephalitogens [ 4 ] . As immu- Inset 8.1 nology boomed in the second half of the twenti- Pertussis toxin is a large molecule produced eth century, and the research on encephalitogens by the bacterium, B ordetella pertussis , resulted in reproducibility of the model, the composed of six subunits and is an exo- immunology of EAE attracted more and more toxin, meaning it is secreted by the bacte- interest, especially as a rapidly induced model of rium. An effect that is important for autoimmunity. Most EAE projects currently uti- neuroimmunologists is that it is considered lize mice and rats, but in the past, rabbits, guinea essential in many forms of EAE. It is pigs, nonhuman primates, and other animals were thought to exert this effect by impairing the used and continue to be used by some groups. blood–brain barrier and facilitating the The most productive non-rodent work over the infl ux of lymphocytes into the CNS. The last 15 years has been in marmoset monkeys precise mechanism by which the toxin [5 , 6 ] . Work on monkeys always has greater rel- causes this effect is unknown, but it may evance to human disease because of the proxim- have a direct effect on CNS endothelial ity of these animals to humans on the phylogenetic cells in experimental animals. B ordetella tree relative to rodents. The pathology of the mar- pertussis is the causative pathogen of the moset EAE model appears to more closely severe childhood respiratory infection, resemble MS than rodent EAE, but nonhuman whooping cough. primates are much more diffi cult to work with than are rodents. E ncephalitogens currently used for EAE research vary, and some laboratories still use spinal The natural course of most forms of EAE is cord or brain homogenates or myelin. However, the development of weakness within about a most laboratories use more purifi ed encephalito- week after immunization, with disability peaking gens such as myelin basic protein (MBP), proteo- at about 10–14 days after immunization, followed lipid protein (PLP), or myelin oligodendrocyte by resolution to baseline strength by 3–4 weeks protein (MOG), or synthetic peptides which repre- after immunization. The demyelination and sent part of the sequences of these proteins. The infl ammation in the CNS usually follows this most commonly used strain of mouse for these temporal pattern also. The weakness in EAE is experiments is the SJL strain, which appears to associated with fl accidity, i.e., decreased muscle have poorly defi ned genetically determined traits tone, a feature of EAE in which it differs from 1 Animal Models of MS 85 MS, where spasticity, i.e., increased muscle tone, caused by CNS injury, is predominant. The fl ac- cidity found in EAE may be due to the fact that many EAE models have nerve or nerve root involvement. Most EAE investigators use a rela- tively subjective visual assessment grading scale of zero to fi ve plus for grading weakness rather than objective neurobehavioral analyses. There are many variations on this model, since mutant mice (see Inset 8 .2 ) can be genetically engineered to overexpress or underexpress a wide variety of genes which have effects on the course of EAE. Fig. 8.1 Course of MOG-induced EAE in mice. The x -axis is days post-immunization with a myelin oligo- dendrocyte glycoprotein (MOG) peptide and the y -axis is Inset 8.2 Mutant Mice a clinical score based on visualization of the mouse and estimate of its weakness. EAE is suppressed in glial matu- Genetically engineered mice, also called ration factor (GMF) knockout mice. The wild-type, i.e. mutant mice, have been used extensively in normal mice, show normal development of EAE with neuroimmunology research, especially in peak 14 days after immunization with MOG peptide models of EAE. Mutant mice can be loosely divided into knockout mice which have a deletion of a gene, and transgenic mice, in The temporal pattern of EAE (Fig. 8.1 ) is which a gene is inserted. For instance, a essentially identical to that of post-vaccinial auto- recently developed mutant mouse is the immune encephalomyelitis, as outlined in Chap. MOG peptide 92–106 T-cell receptor trans- 3 , for the Semple rabies vaccine encephalomyeli- genic mouse in which most T cells express tis (SAE). Stage 1 is the immunization with the this genetically engineered receptor and encephalitogen. In contrast to SAE, in which the react to MOG [2 1 ] ; this mouse spontane- main reason for the immunization is protection ously gets EAE without the need for immu- from rabies, and the sensitization to CNS anti- nization or other manipulations. gens is an unwanted side effect, in EAE, the sen- In 2007, Capecchi, Smithies, and Evans sitization to the encephalitogen is the main received the Nobel Prize for the develop- purpose of the immunization. In stage 2, usually ment of knockout mice, utilizing homolo- in the fi rst few days after the immunization, local gous recombination in which nucleotide lymph nodes drain the site of immunization, and sequences are exchanged between similar the antigen is processed within these nodes by strands of DNA. The fi rst knockout mouse dendritic cells and other antigen-processing cells was made in 1989. An example of the use such as macrophages. By the end of the fi rst of knockout mice in EAE research is the week, in stage 3, CNS antigen-specifi c lympho- observation that EAE can be induced in cytes proliferate and enter the circulation, and mice in whom the components critical for begin to enter the CNS. Once they enter the CNS the membrane attack complex (MAC), an encephalitogen-specifi c lymphocytes are retained important part of the complement system, there by the presence of the antigen and do not have been knocked out [2 2 ] . These experi- traffi c out of the CNS, while lymphocytes with ments indicate that MAC is not an essential specifi cities for other antigens are not retained in set of genes in EAE induction; it would the CNS, and either traffi c back into the circula- have almost impossible to prove this if a tion, or alternatively apoptose within the CNS mutant mouse was not available. (see apoptosis, Chap. 1 ), i.e., undergo pro- grammed cell death (PCD). 86 8 Experimental Models of MS Stage 4, spanning from about day 10 to day 20 phasic phenomenon, and, given the absence of after immunization, represents the period of most accumulating neurological injury, it is not a good active infl ammation within the CNS and also is model for the progressive disability of MS, that the period of the development of maximum neu- aspect of the disease most important to the patient rological signs in the animal. The animal’s spinal and their treating physician. cord, which under normal circumstances con- Groundbreaking work by Ben-Nun, Wekerle, tains only an occasional mononuclear cell, will and others in the early 1980s [9 ] revealed that T have sites of large numbers of them, mostly lym- cells could mediate EAE, which led to hope that phocytes and macrophages. Initially, mononu- a new era of understanding EAE and possibly clear cells accumulate in the perivascular space MS was dawning. Since then the T cell has been between the basement membranes of the cere- the primary cell researched in EAE. In fact, brovascular endothelial cells and of the basement because of the importance of the T cell in EAE, membrane associated with astrocytic endfeet many investigators extrapolated to MS by (Fig. 3.1 ). Over time, the mononuclear cells assuming that MS was a “T-cell-mediated auto- move through the basement membrane and the immune disease.” However, it appears that the glia limitans comprising astrocytic endfeet and injury to the CNS in most forms of EAE is into the parenchyma of the CNS. Demyelination caused by a complex mix of components that also appears at this stage, although the extent of cannot be reproduced by a single cell type. For demyelination varies widely in different models instance, anti-MOG antibody is necessary of EAE. for maximum clinical disease in some models of By 3 weeks after immunization in stage 5, MOG-induced EAE, and weakness can be infl ammation is abating and recovery is begin- amplifi ed by the administration of anti-MOG ning. EAE, in most models, is monophasic and monoclonal antibodies, but not antibodies to after the peak of infl ammation and disease ani- irrelevant antigens. mals improve relatively rapidly, often to being The precise type of T cell or mixture of T cells completely normal. In some EAE models, the which are most pathogenic in EAE is still a matter animals improve markedly after the peak of dis- of controversy. In Ben-Nun’s original manuscript ease, but do not completely recover back to their describing T-cell mediation of EAE [ 9 ] , lympho- baseline and there is permanent injury to the CNS cyte lines were utilized. These were complex caused by the acute phase of the disease. Finally, mixtures of cells, not T cell clones, and since that some models are described as being “chronic, pivotal observation, populations of T cells, pre- relapsing EAE” [7 ] . However, the degree of chro- sumably interacting together, rather than a mono- nicity is usually mild. For instance, in a recent clonal population, have been the most potent publication authors evaluated a therapy, surgical effectors. Most investigators until recently lymph node excision, in three different models of assumed that the most pathogenic cells were mouse EAE, which they described as “acute, CD4+, interferon-g secreting cells (sometimes chronic, and chronic relapsing”, induced by called Th1 cells). However, recent evidence immunizing SJL, C57Bl/6, or Biozzi ABH mice points to the importance of Th17 cells, CD4+ T with proteolipid protein peptide, myelin oligo- cells that secrete IL-17, which are developmen- dendrocyte glycoprotein peptide (35–55), or tally distinct from Th1 and Th2 cells (Fig. 8.2 ). In myelin oligodendrocyte glycoprotein (8–21) [ 8 ] . humans, these cells are induced by a combination However, although there were minor differences of IL-23, IL-1b , and TGF- b and secrete IL-17 in the course of the neurological disability in and IL-22. these mice, in all three groups of animals the dis- There are many variants of EAE, some of them ability peaked at 10–15 days post-immunization made possible by the availability of genetically and had completely resolved by the end of the altered mutant mice. A notable one is the TCR- second month. Thus, EAE is generally a mono- transgenic mouse [1 0] in which

a large percentage 1 Animal Models of MS 87 Fig. 8.2 Differentiation of effector T helper subsets from ferentiate in response to IL-4. The Th17 cell subset devel- naïve CD4 T cells. The fi rst step is activation of naïve ops in response to IL-6 or IL-21 and TGF-b , which is CD4+ T cells by professional antigen-presenting cells enhanced in the presence of IL-1b and TNF- a . Thus, (APCs) with IL-12 being an important stimulatory T-cell differentiation is determined by a combination of cytokine. Th1 cells upregulate IFN-g , while Th2 cells dif- cell type and cytokine environment of T-cell receptors are specifi c for MBP. These attempts to understand MS. Ultimately, EAE can mice develop EAE simply with the administration be considered important as a means to under- of pertussis toxin. One way of producing EAE in standing infl ammation in the CNS. Despite its an animal is passive transfer of cell populations limitations, much will continue to be learned into naive mice, which allows determination of from EAE about a wide variety of phenomena which types of cells are critical for EAE induction relevant to human disease including the blood– (see “passive transfer”, below). Another interest- brain barrier, effects of resident CNS populations, ing recently developed model is that of focal immune cell traffi cking through the CNS, and lesions causing demyelination, infl ammation, and cytokine production and cytokine effects. weakness, induced by intraspinal injection of the protein vascular endothelial growth factor (VEGF) in rats with high levels of anti-MOG antibodies 1.2 Viral [1 1 ] . These variations of the “standard” EAE pro- vide greater opportunities to learn about the biol- CNS demyelination is produced by a wide variety ogy of EAE. of viruses in animals [1 3] ; the list includes visna B ecause of the many dissimilarities between virus infection in Icelandic sheep, caprine arthri- EAE and MS, a direct extrapolation of fi ndings in tis-encephalitis virus infection in goats, Semliki EAE to MS is unwarranted. A recent editorial, Forest virus in mice, and canine distemper and its titled “Experimental Allergic Encephalomyelitis: variants in dogs and sea mammals. These viruses A Misleading Model of Multiple Sclerosis” [1 2 ] , represent a broad spectrum of viruses without any concluded that “we therefore are forced to exam- similarities, except that they all are RNA viruses. ine MS without the restraints of EAE”, and makes The most widely used viral models for MS are the a reasonable argument that EAE has been inap- Theiler’s murine encephalomyelitis virus (TMEV) propriately used to provide a framework for and mouse hepatitis virus (MHV) models. 88 8 Experimental Models of MS T MEV is a picorna virus, a very small virus of Characteristic MS TMEV EAE only 8,100 nucleotides in the Cardiovirus genus. Exacerbations/remissions Yes No No After intracerebral injection of the virus into a and progressive disability mouse, there are two phases of the disease. The Progressive disability Yes Yes No fi rst is an acute mild, usually subclinical enceph- Monophasic, hyperacute No No Yes disease with rapid recovery alitis, but if too much virus is injected or if the Viral etiology ? Yes No mouse is immunosuppressed, the early encepha- Infl ammation Yes Yes Yes litis can be deadly. During this fi rst phase, the Demyelination Yes Yes Yes infection is predominantly of neurons. The Disability progression over 25% 20% No chronic phase beginning about a month after what % of life span progression infection consists of slowly progressive disabil- Antibody production Yes Yes No ity, characterized by demyelination, infl amma- in the CNS tion, and axonal damage. The weakness is Immunoglobulin Yes Yes No deposition in the CNS associated with spasticity and occasionally severe muscle spasms. The viral load in the CNS in the chronic phase is stable over time, with the pri- In the MHV model, also called JHMV from mary reservoir being astrocytes, and the progres- the most commonly used strain of MHV, demy- sive damage to the CNS is presumed to be due to elination, infl ammation, and high viral levels in the large amount of infl ammation in the CNS. the CNS occur as a monophasic event, followed Except for the lack of relapses the clinical picture by slow diminution of viral load and partial reso- resembles human MS; the pathology is very sim- lution of demyelination and infl ammation. ilar also, as is the presence of plasma cells and However, the virus is not completely cleared and production of IgG within the CNS. A disadvan- new areas of demyelination appear for prolonged tage for researchers, though, is that mice can take periods, possibly due to local reactivation of virus months to become weak after the initial infec- in areas of the CNS [1 3 ] . MHV is also a tion; in contrast, weakness in EAE occurs within well-studied model of acute viral encephalitis a few weeks of immunization. (see Chap. 12 ). T he TMEV model has a number of advantages Canine distemper virus (CDV) and other over EAE as outlined in the table below. Neither related viruses are morbilliviruses related to TMEV nor EAE mirror the combination of exac- measles that cause demyelination in a variety of erbations/remissions and progressive disability of animals in the wild; these viruses are the sub- the human disease. However, the progressive dis- jects of some recent reviews [1 4, 15 ] . The most ability of the TMEV model is particularly attrac- medically important morbillivirus is measles tive as a target since neurologists, at this time in virus which generally causes an acute viral ill- the history of multiple sclerosis, have so many ness in children, and has a signifi cant mortality therapies that have been shown to be effective for especially in the developing world where mea- exacerbations (see Chap. 7 ), and what is needed sles vaccination is less common. Measles virus, are therapies that affect disability progression. For however, also causes two rare syndromes, sub- reasons that are not clear in either MS or TMEV, acute sclerosing panencephalitis (SSPE) and both diseases progress through 20–25% of the life measles inclusion body encephalitis (MIBE), span of the animal and then usually almost com- described in more depth in Chap. 16 ; SSPE can pletely plateau; i.e., neither patients nor mice com- mimic MS. monly die of progressive neurological disability. CDV, which in the wild has primarily affected Both TMEV and MS have prominent involvement dogs and also wild cats and other mammals, ini- of the humoral arm of the immune response, with tially causes a systemic infection, transmitted antibody being both produced and deposited in the through the lungs, that ultimately invades the CNS; in contrast, in most models of EAE, there is CNS, and results in glial cell infection. little evidence of B-cell or antibody involvement. Subsequently, the virus persists chronically and 2 In Vitro Models of MS 89 causes multifocal, infl ammatory demyelinating lesions resembling MS. The precise pathogenesis 2 In Vitro Models of MS of the lesions is controversial, but appears to be related to a combination of persistent virus, mac- Some researchers utilize isolated CNS tissue, rophage activation, strongly upregulated cytokine such as brain slices or isolated optic nerves, to responses, and an infl ammatory pathology con- investigate the role of various cells or molecules sisting of perivascular infi ltration with plasma to injure or demyelinate. For instance, cerebro- cells and lymphocytes. Oligodendrocytes, though spinal fl uid from MS patients but not controls has infected by CDV, are not lysed. Morbilliviruses been shown to block transmission of action also cause infl ammatory demyelination in marine potentials through isolated optic nerves. Other mammals including seals, dolphins, whales, and researchers have used isolated optic nerves from porpoises. animals with EAE to analyze the cytokines and Retrovirus infections can also cause demyeli- mediators involved in the immune attack on nating, infl ammatory disease in animals; the most myelin. One advantage of these ex vivo models is well-known retrovirus causing human disease is that functional aspects of axonal conduction such human immunodefi ciency virus (HIV), the neu- as action potentials can be correlated with mea- rological manifestations of which will be surement of immune cells and molecules. reviewed in Chap. 12 . Visna virus was the fi rst Advances in the culturing of cells ex vivo has retrovirus isolated in 1957 and is similar to allowed studies of CNS endothelial cell function, TMEV in causing a subacute encephalitis, fol- commonly using inserts in which endothelial lowed by a chronic demyelinating encephalomy- cells are grown on a porous substrate that allows elitis; susceptible animals are sheep. Another molecules and cells to pass from one chamber to retrovirus causing demyelination is caprine another, mimicking the blood–brain barrier. Since arthritis encephalitis virus (CAEV), which causes increased passage of mononuclear cells across infl ammatory demyelination in the brain and spi- CNS endothelial cells is an important pathology nal cord in young goats. in EAE and MS, this technology has yielded important fi ndings. For instance, the cell culture insert approach was helpful in the analysis of 1.3 Demyelination Induced agents such as natalizumab which target adhe- by Toxins sion molecules expressed on endothelial cells. Demyelination can be induced also by adminis- tration of toxic agents in noninfl ammatory mod- 3 Animal Models of els of the demyelination of MS. In the cuprizone Neuromyelitis Optica (NMO) model of CNS demyelination, mice are fed and the Use of Passive Transfer cuprizone, a copper chelator, and subsequently Models develop severe demyelination due to cell death of oligodendrocytes. Although the effect is NMO, described in Chap. 6 , is an important dis- thought to be due to the copper chelation, the ease for at least three reasons: fi rst, it is frequently effect is not reversed by supplementation with a particularly devastating illness causing progres- copper. Once the cuprizone is removed, remy- sive visual loss and spinal cord injury; second, it elination begins to occur, so this model can also is frequently misdiagnosed as MS and needs to be be used to look at processes which might hinder differentiated from that disease because treatment or accelerate remyelination. If focal demyelina- is different; and third, its etiopathogenesis is much tion is required, that can be induced by injec- better defi ned than MS in that it appears to be tion with lysolecithin or related compounds. caused by an autoantibody. For all these reasons, These and similar models have been recently there has been extensive interest in developing reviewed [1 6 ] . animal models, and a number of laboratories have 90 8 Experimental Models of MS been successful [1 7, 18 ] . In these models, the experimental autoimmune encephalomyelitis research. mediator of injury is IgG from patients with NMO Brain. Aug 2006;129(Pt 8):1953–71. 3. Rivers TM, Spunt DH, Berry GP. Observations on which results in injury either after being directly attempts to produce acute disseminated encephalomy- injected into the CNS or via intravenous injection elitis in monkeys. J Exp Med. 1933;58:39–53. after inducing EAE and opening the blood–brain 4. Waksman BH, Porter H, Lees MD, Adams RD, Folch barrier. The pathogenic IgG can be either isolated J. A study of the chemical nature of components of bovine white matter effective in producing allergic directly from the blood of NMO patients or can encephalomyelitis in the rabbit. J Exp Med. be made by recombinant technology. Thus, these 1954;100(5):451–71. models fall into a category of experimental mod- 5. t Hart BA, Laman JD, Bauer J, Blezer E, van Kooyk els called passive transfer in which the disease Y, Hintzen RQ. Modelling of multiple sclerosis: les- sons learned in a non-human primate. Lancet Neurol. can be induced in a normal animal by injection of Oct 2004;3(10):588–97. pathogenic immunoglobulin or cells. 6. Genain CP, Hauser SL. Experimental allergic enceph- The defi nition of passive transfer is the con- alomyelitis in the New World monkey Callithrix jac- ferring of an immune response to a nonimmune chus. Immunol Rev. Oct 2001;183:159–72. 7. Steinman L. Assessment of animal models for MS host by injection of immunoglobulin or lympho- and demyelinating disease in the design of rational cytes from an immune donor; thus, passive trans- therapy. Neuron. Nov 1999;24(3):511–4. fer models of neuroimmunological disease 8. van Zwam M, Huizinga R, Heijmans N, et al. Surgical

involve the transfer of cells or immunoglobulin excision of CNS-draining lymph nodes reduces relapse severity in chronic-relapsing experimental into an animal to induce a model of disease. The autoimmune encephalomyelitis. J Pathol. Mar 2009; most commonly used model using passive trans- 217(4):543–51. fer of IgG in neuroimmunology is that of pas- 9. Ben-Nun A, Wekerle H, Cohen IR. The rapid isola- sively transferred myasthenia gravis (MG), fi rst tion of clonable antigen-specifi c T lymphocyte lines capable of mediating autoimmune encephalomyelitis. used by Toyka [ 19 ] ; experimental models of MG Eur J Immunol. Mar 1981;11(3):195–9. are described in Chap. 10 . Passive transfer EAE, 10. Goverman J, Woods A, Larson L, Weiner LP, Hood using mononuclear cells from immune animals, L, Zaller DM. Transgenic mice that express a has also been utilized extensively, allowing char- myelin basic protein-specifi c T cell receptor develop spontaneous autoimmunity. Cell. 1993;72(4): acterization of pathogenic cell populations. 551–60. Passive transfer EAE can also be elicited with 11. Sasaki M, Lankford KL, Brown RJ, Ruddle NH, anti-MOG antibodies [2 0 ] . Passive transfer Kocsis JD. Focal experimental autoimmune encepha- experiments in a variety of diseases such as EAE, lomyelitis in the lewis rat induced by immunization with myelin oligodendrocyte glycoprotein and experimental myasthenia, and experimental intraspinal injection of vascular endothelial growth NMO have proved helpful in identifying the pop- factor. Glia. 2010;58:1523–31. ulations of cells or antibodies which might be 12. Sriram S, Steiner I. Experimental allergic encephalo- pathogenic in human disease. myelitis: a misleading model of multiple sclerosis. Ann Neurol. Dec 2005;58(6):939–45. For those interested in a more detailed insight 13. Stohlman SA, Hinton DR. Viral induced demyelina- into various aspects of experimental models of tion. Brain Pathol. Jan 2001;11(1):92–106. MS, I recommend the book, Experimental mod- 14. Vandevelde M, Zurbriggen A. Demyelination in els of multiple sclerosis , edited by Ehud Lavi, canine distemper virus infection: a review. Acta Neuropathol. Jan 2005;109(1):56–68. Cris S. Constantinescu, Springer, 2005. 15. Sips GJ, Chesik D, Glazenburg L, Wilschut J, De Keyser J, Wilczak N. Involvement of morbilliviruses in the pathogenesis of demyelinating disease. Rev Med Virol. 2007;17(4):223–44. References 16. Blakemore WF, Franklin RJ. Remyelination in exper- imental models of toxin-induced demyelination. Curr 1. Waksman BH. Demyelinating disease: evolution of a Top Microbiol Immunol. 2008;318:193–212. paradigm. Neurochem Res. Apr 1999;24(4):491–5. 17. Bennett JL, Lam C, Kalluri SR, et al. Intrathecal 2. Gold R, Linington C, Lassmann H. Understanding pathogenic anti-aquaporin-4 antibodies in early neu- pathogenesis and therapy of multiple sclerosis via romyelitis optica. Ann Neurol. Nov 2009;66(5): animal models: 70 years of merits and culprits in 617–29. References 91 18. Bradl M, Misu T, Takahashi T, et al. Neuromyelitis myelin oligodendrocyte glycoprotein. Eur J Immunol. optica: pathogenicity of patient immunoglobulin 2002;32(7):1905–13. in vivo. Ann Neurol. Nov 2009;66(5):630–43. 21. Pollinger B, Krishnamoorthy G, Berer K, et al. 19. Toyka KV, Drachman DB, Griffi n DE, et al. Myasthenia Spontaneous relapsing-remitting EAE in the SJL/J gravis. Study of humoral immune mechanisms by mouse: MOG-reactive transgenic T cells recruit passive transfer to mice. N Engl J Med. 1977; endogenous MOG-specifi c B cells. J Exp Med. 296(3):125–31. 2009;206(6):1303–16. 20. Lyons JA, Ramsbottom MJ, Cross AH. Critical role of 22. Barnum SR, Szalai AJ. Complement and demyelinat- antigen-specifi c antibody in experimental autoim- ing disease: no MAC needed? Brain Res Rev. 2006; mune encephalomyelitis induced by recombinant 52(1):58–68. Guillain–Barré Syndrome (GBS) and Other Immune-Mediated 9 Neuropathies 1 Defi nition cise and best name for the diagnosis in the majority of GBS patients is AIDP, acute Guillain–Barré syndrome (GBS) is the most com- infl ammatory demyelinating polyneuropa- mon serious immune-mediated disease affecting thy, which describes the disease well and the peripheral nervous system (PNS). GBS is an allows more precise classifi cation, but acute diffuse illness affecting nerve roots and eponyms in neurology die hard. peripheral nerves, and occasionally the cranial nerves, often ascending from the feet over hours to days to the arms and sometimes bulbar mus- cles, resulting in motor weakness, and relatively sparing sensory functions; most patients who sur- 2 Etiopathogenesis vive the acute paralysis recover completely within months. The disease was fi rst described by the In one of Landry’s initial cases, his senior physi- French neurologist, Landry, in 1859 (Inset 9 .1 ). cian diagnosed one of his patients as having hyste- ria; time would prove this to be clearly incorrect. Inset 9.1 Another theory by Landry’s contemporaries was What Should This Disease that it was a variant of diphtheria. This diagnosis Be Called? was closer to being correct since both diphtheritic M ost physicians call this disease as neuropathy and GBS are demyelinating neuropa- Guillain–Barré syndrome (GBS), although thies (see “demyelination” in C hap. 2) . Neurologists it was originally described by Jean Landry ultimately found them to be distinct diseases when de Thézillat (usually referred to as Landry) the causative pathogen of diphtheria was found to in 1859 before Georges Guillain or Jean be Corynebacterium diphtheriae by Friedrich Alexander Barré was born; thus the disease Loeffl er in 1884 (see Inset 9.2) , and patients with is sometimes called Landry’s paralysis. GBS were found to not be infected. Subsequently, Despite the fact that Andre Strohl, a physi- GBS has been thought to be immune-mediated, ologist, contributed to Guillain and Barré’s due to a response against a “stimulating agent”, work, his name is not frequently added to usually an infection; this hypothesis is based on the syndrome. Thus, if one were a strict the epidemiology, i.e., its occurrence frequently eponymist, the disease would be Landry– after bacterial or viral infections, and on investiga- Guillain–Barré–Strohl syndrome. The pre- tions in experimental autoimmune neuritis (EAN), GBS’s animal model. A.R. Pachner, A Primer of Neuroimmunological Disease, 93 DOI 10.1007/978-1-4614-2188-7_9, © Springer Science+Business Media, LLC 2012 94 9 Guillain–Barré Syndrome (GBS) and Other Immune-Mediated Neuropathies Inset 9.2 Diphtheria and Its Recent Resurgence Within the differential diagnosis of GBS is diphtheritic neuropathy caused by infection with the bacteria C orynebacteria diphtheriae . Brain’s textbook D iseases of the Nervous System in its seventh edition published in 1969, devoted three pages to diphtheritic neu- ropathy, and an equal amount to GBS. However, most American neurologists, though they will diagnose many cases of GBS in their lifetimes, will never see diphtheritic neuropa- Fig. 9.1 Diphtheritic membrane. Nasopharyngeal diphtheria with extensive membrane formation in thy in their practices because diphtheria vac- a 4-year-old child cination, usually in combination with pertussis and tetanus, i.e. the DPT vaccine, is required for school-age children in the USA, and there is almost no diphtheria in the USA. There DN usually presents with palatal paraly- were only three cases of diphtheria in the USA sis as the fi rst manifestation while symptoms between 2000 and 2007, an amazing contrast of generalized polyneuropathy do not to the 1920s where there were estimated to be develop until usually weeks later; rarely, more than 100,000 cases per year in the USA. generalized weakness can be the fi rst mani- Thus, the absence of diphtheritic neuropathy festation of DN. There is commonly the represents a triumph of public health vigi- appearance on examination of the mouth and lance; diphtheria will return if this vigilance throat, a diphtheritic “membrane” (Fig. 9.1 ). fails. Such an event occurred in the former Problems with dysarthria are common in Soviet Republics after the breakup of the DN, because of early involvement of the pal- Soviet Union when diphtheria vaccination ate and uvula. Otherwise, DN and GBS can rates dropped. By 1998, there were as many as be very similar, both demonstrating severe 200,000 cases of diphtheria in the former hyporefl exive fl accid weakness. However, Soviet Union countries with 5,000 deaths. because diphtheria toxin can have its effect This resurgence of diphtheria also led to a pre- locally early, paralysis of bulbar muscles, dictable increase in cases of diphtheritic neu- i.e. muscles innervated by the cranial nerves, ropathy (DN), which was analyzed in depth by is very common in DN, occurring in 98% of Logina and Donaghy [1 2 ] who compared clin- DN patients in Logina’s series, while it is ical features of 50 adults with DN and con- unusual in GBS, occurring in only 10% of trasted them to 21 patients with GBS. DN is her GBS cases. Even DPT-vaccinated indi- thought to be due to demyelinative effects of viduals can have an attenuated form of DN, the diphtheria toxin. The fi rst Nobel Prize in if they are exposed to the bacteria; thus, any Medicine in 1901 was awarded to Emil von individual who has a “bulbar form of GBS” Behring for his development of diphtheria should be considered to possibly have DN if antitoxin, which is still used and is highly they have traveled to countries of the former effective in preventing diphtheritic neuropathy Soviet Union or other areas where diphtheria if given early in the course of the infection. is endemic. 4 Epidemiology and Etiopathogenesis 95 T he disease is not unique to humans and which is a common pathogen causing infectious occurs naturally in dogs (e.g., coonhound paraly- diarrhea. In China, GBS, particularly the AMAN sis) and in nonhuman primates. Coonhound form (see below), is epidemic, occurring in the paralysis appears to be due to an immune reac- summer months, and is often associated with an tion to proteins present in the saliva of raccoons antecedent diarrheal infection, commonly due to and requires previous exposure to raccoons in C. jejuni [ 1 ] . Initially, it was hypothesized that a susceptible dogs; the disease does not occur in phenomenon termed molecular mimicry was cats. It occurs 1–2 weeks after exposure to the responsible for the GBS. That is, after the human raccoon, similar to the latency in humans after developed C . jejuni infection, and developed anti- exposure to the “stimulating agent.” Affected bodies to glycolipids on the surface of the C . dogs initially have gait problems progressing to jejuni bacteria, including the glycolipid GM1, weakness of all limbs, usually beginning in the these antibodies caused an immune attack on the hind limbs then moving forward to the forelimbs. GM1 in the GBS patient’s nerve tissue. However, Deep tendon refl exes (DTRs) are lost and respi- this initial hypothesis could not be defi nitively ratory paralysis may develop. proven and considerable evidence against it has emerged. However, the hypothesis that GBS is due to 3 Pathology pathogenic molecules in the serum of GBS patients has been confi rmed to some extent by the There are few studies on pathology in GBS benefi cial effect of plasmapheresis, a procedure because most patients with GBS do not undergo in which large volumes of the patient’s plasma nerve biopsy. When tissue is obtained, pathology are replaced with normal saline (see treatment, on gross examination is not usually abnormal, below). Many investigators feel that the patho- but microscopic analysis can show demyelina- genic material is the immunoglobulin fraction, tion and frequently infl ammation in nerve roots specifi cally antibodies to glycolipids, i.e., non- and peripheral nerves. The mononuclear cell protein molecules that are combinations of car- infi ltrate was one of the fi rst hints that the under- bohydrate and lipid moieties. A large group of lying etiology was likely immune-mediated. molecules called gangliosides, which are highly Demyelination is found predominantly near enriched in myelin, have undergone extensive nodes of Ranvier (see Chap. 2 for more on nodes study as being important in the pathogenesis of of Ranvier) often accompanied by the presence GBS. These investigations have not yielded a of infl ammatory cells. Some forms of GBS are great deal of clinical benefi t as yet, although one axonal, and axonal degeneration without demy- type of GBS, the Miller Fisher variant (see clas- elination can be seen on pathological evaluation sifi cation below), is reported as having positive in these varieties. Occasionally, myelitis, i.e. anti-GQ1b antibodies, a type of anti-ganglioside infl ammation of the spinal cord, can be an associ- antibody in 85% of affected patients. Many ated fi nding. researchers in this fi eld feel that anti-GQ1b anti- bodies are indeed pathogenic and there is some evidence for this in the research laboratory. 4 Epidemiology and GBS usually attacks myelin without directly Etiopathogenesis damaging neurons. Remyelination is likely an early feature of GBS, but is initially overwhelmed There

is no known genetic predisposition to GBS. by damage to myelin. Recovery can be relatively There may be an increased incidence with increas- rapid once continued damage to myelin halts and ing age. Most cases of GBS have an antecedent remyelination continues. Most patients with GBS infection within the previous few weeks, and there ultimately recover completely even without treat- has been increasing evidence that a triggering ment. The axon remains healthy in most patients pathogen is the bacterium C ampylobacter jejuni , with GBS, and simple remyelination by Schwann 96 9 Guillain–Barré Syndrome (GBS) and Other Immune-Mediated Neuropathies cells is the only requirement, a process which is had a severe case requiring one and half months in usually relatively rapid, i.e., weeks to a few an intensive care unit. The incidence of the disease months. This rapid recovery is, in contrast, to pro- is low, only about 2 cases per 100,000 population cesses which damage the axon, in which case per year, but the disease is extremely important Wallerian degeneration (see Chap. 2 ) can occur, since it can be fatal if not diagnosed early and and complete recovery frequently does not occur. treated by respiratory support. 5 Clinical Manifestations 6 Natural History and Prognosis An excellent description of the disease is by Most patients with GBS, even those with severe Landry who fi rst described GBS in 1859: forms requiring intubation to maintain respiration, the main problem is usually a motor disorder char- have full or nearly full recoveries, which are accel- acterised by a gradual diminution of muscular erated by plasmapheresis therapy. For instance, strength with fl accid limbs and without contrac- those who presented to the hospital with weakness tures, convulsions or refl ex movements of any kind. In almost all cases micturition and defaeca- so severe that they required respiratory support tion remain normal. One does not observe any required 6 months of recovery before they could symptoms referable to the central nervous system, walk, while those who did not require respiratory spinal pain or tenderness, headache or delirium. support during the worst of their GBS required The intellectual faculties are preserved until the end. The onset of the paralysis can be preceded by only 2 months of recovery. Treatment with plasma- a general feeling of weakness, pins and needles pheresis improved those numbers to 3 and 1.5 and even slight cramps. Alternatively the illness months, respectively [2 ] . Death from respiratory may begin suddenly and end unexpectedly. In both failure, relatively common in Landry’s time, is now cases the weakness spreads rapidly from the lower to the upper parts of the body with a universal ten- unusual because of the availability of ventilators. dency to become generalised. The fi rst symptoms always affect the extremi- ties of the limbs and the lower limbs particularly… The paralysis then becomes generalised but more 7 Classifi cation severe in the distal parts of the extremities. The pro- gression can be more or less rapid. It was 8 days in The most common form occurring in about 95% 1 and 15 days in another case which I believe can be of patients with GBS in the USA and Europe is classifi ed as acute. More often it is scarcely 2 or 3 days and sometimes only a few hours. AIDP, the “classical” form which is primarily When the paralysis reaches its maximum inten- demyelinating; in this form axonal function is sity the danger of asphyxia is always imminent. spared, and the prominent demyelination is respon- However in eight out of ten cases death was sible for most of the neurological defi cit. In 1991, avoided either by skillful professional intervention or a spontaneous remission of this phase of the ill- McKhann and colleagues described a new form of ness. In two cases death occurred at this stage . . . GBS which came to be called acute motor axonal When the paralysis recedes it demonstrates the neuropathy (AMAN) [3 ] . AMAN was distinct reverse of the phenomenon which signaled its from AIDP in being primarily seen in epidemics in development. The upper parts of the body, the last to be affected, are the fi rst to recover their mobility children in rural China and involving axonal func- which then returns from above downwards.” (from tion on electrophysiological testing (Table 9 .1 ). the Guillain–Barré Syndrome Support Group of In neither AIDP nor AMAN is sensory involve- UK and Ireland’s web site: h ttp://www.gbs.org.uk/ ment prominent, while in another form of GBS, history.html ). called acute motor and sensory axonal neuropathy Another excellent description of the disease (AMSAN), sensory involvement is more obvious. from the patient’s viewpoint is the book, N o Still another form is the Fisher variant of GBS, Laughing Matter , written by Joseph Heller and his sometimes called the Miller Fisher syndrome or friend Speed Vogel, after Heller contracted GBS in MFS, described by the neurologist C. Miller Fisher 1981. Heller, best known as the author of C atch-22 , in 1956, in which the triad of ophthalmoplegia, 9 Therapy 97 Table 9.1 Characteristics of AIDP and AMAN the “dissociation albumino-cytologique” fi rst Characteristic AIDP AMAN described by Guillain, Barré, and Strohl in Found in Adults Children 1916, i.e., markedly elevated protein with normal Geography World Rural China or only slightly elevated white cell count. Occurrence Sporadic Epidemic Electromyography and nerve conduction studies Electrophysiology Demyelinating Axonal reveal prolonged nerve conductions, proximally and distally, consistent with demyelination. Very ataxia, and arefl exia is present with limb weakness few diseases mimic AIDP, but other causes of being absent or less prominent. Overlap syndromes acute neuropathy should be considered such as of the various forms of GBS are not rare, with toxic neuropathies, Lyme disease, or vasculitis; varying motor vs. sensory involvement, limb rare conditions such as diphtheria, tick paralysis, weakness, respiratory involvement, ophthalmople- or porphyria are in the differential. gia (inability to move the eyes), facial and other cranial nerve palsies, and sensory neuropathies. AIDP is generally not associated with any charac- 9 Therapy teristic autoantibody, while the other forms of GBS have been found more commonly associated with The therapy over the last century which has made anti-ganglioside antibodies. In the majority of the biggest impact on improving care for GBS patients with MFS, anti-GQ1b antibodies are pres- patients was the development of ventilators, ent. In this respect, MFS resembles another infl am- beginning with the negative-pressure “iron lungs” matory syndrome called Bickerstaff’s brainstem in the early twentieth century to the modern posi- encephalitis. In the 1950s, Bickerstaff reported tive pressure devices, to support ventilation eight patients with impaired consciousness of impaired by the weakness of the disease. which all had ataxia, seven had ophthalmoplegia, Ventilators in addition to modern advances in and four hypo- or arefl exia. From the time of their care of critically ill patients in intensive care units fi rst descriptions, MFS and Bickerstaff’s were has saved untold lives in patients with severe considered to be related, and the later fi nding that GBS. Since the natural history of GBS is usually anti-GQ1b antibodies were present in high per- one of complete recovery, these critically ill centages of both diseases supported the clinical patients, after their harrowing experience with resemblance. the disease, usually return to normal lives. Two immunoactive treatments, plasma exchange and intravenous immunoglobulin G 8 Diagnosis (IVIg), have been shown to be effective in short- ening the duration of weakness, while another, The diagnosis of AIDP, the most common form corticosteroids, has been shown to be ineffective of GBS, is usually straightforward for neurolo- (see Chap. 19 for a description of these treat- gists. Symptoms consist of motor weakness out ments). Because of a large Dutch study compar- of proportion to sensory symptoms with an acute ing plasma exchange and IVIg which demonstrated onset and rapid progression usually over a few at a minimum, the equivalence, and possibly days, but rarely over hours or over a few weeks. superiority of IVIg over plasma exchange [ 4 ] , The weakness is frequently ascending from the many clinicians use IVIg at the dose used in the legs to the arms to bulbar muscles. Respiratory Dutch study, 0.4 g/kg/day over 5 days. The use of involvement is common, frequently requiring IVIg in the treatment of GBS has been recently intubation for respiratory support. On examina- reviewed in depth for the Cochrane reviews [5 ] . tion, there is motor weakness with absent or min- Given the effi cacy of Eculizumab, an anti- imal sensory fi ndings. DTRs are usually absent, complement monoclonal antibody, in a mouse rarely can be present, but should be markedly model of GBS [6 ] , agents targeting complement diminished. Cerebrospinal fl uid analysis reveals appear ready for clinical studies. 98 9 Guillain–Barré Syndrome (GBS) and Other Immune-Mediated Neuropathies 10 GBS’s Cousin: Chronic 11 Neuropathy Associated Infl ammatory Demyelinating with Monoclonal Gammopathy Polyneuropathy Immunoglobulin, as described in Chap. 1 , is pres- Infl ammation within nerves associated with ent in blood normally as billions of different injury can be constant not just transient. GBS has molecules, composed of millions of clonal a cousin, chronic infl ammatory demyelinating populations. Occasionally, one clone can pre- polyneuropathy (CIDP), in which infl ammation dominate, i.e., monoclonal gammopathy (see is persistent, or possibly recurrent, and the injury Inset 9 .3 ), both in patients with diseases such as is not transient as it is in AIDP. Criteria for the multiple myeloma, a B-cell malignancy, and in diagnosis of CIDP are not universally accepted, apparently healthy individuals; the latter of these and there have been many different iterations two situations is sometimes called benign mono- through the years. A recent consensus conference clonal gammopathy or more appropriately mono- defi ned CIDP as clonal gammopathy of unknown signifi cance a chronic non-genetic polyneuropathy, progressive (MGUS). Neuropathies are a more frequent for at least eight weeks, without a serum parapro- occurrence in patients with monoclonal gammo- tein and either 1) recordable compound muscle pathies, either in MGUS or in myelomas, than in action potentials in > or =75% of motor nerves and control groups, and are usually associated with either abnormal distal latency in >50% of nerves or abnormal motor conduction velocity in >50% of gammopathies of IgM, rather than IgG or IgA. nerves or abnormal F wave latency in >50% of The incidence, etiopathogenesis, pathology, nat- nerves; or 2) symmetrical onset of motor symp- ural history, and optimal treatment are unknown. toms, symmetrical weakness of four limbs, and 1% of the population over the age of 25 has proximal weakness in > or =1 limb. [7 ] . MGUS, most of them being IgG gammopathies. This defi nition excludes AIDP because of the stipulation of being chronically progressive over at least 8 weeks. Although this defi nition allows the diagnosis of CIDP to be made without elec- Inset 9.3 Monoclonal Gammopathy trophysiological analysis, most neurologists will The words “monoclonal gammopathy” want electromyography/nerve conduction veloc- describe the condition: “monoclonal” ity (EMG/NCV) confi rmation, since the diagno- means a single clone, and “gammopathy” sis of CIDP generally commits the patient and indicates an abnormal condition of g -glob- neurologist to prolonged therapy. ulins, a type of protein in serum that is CIDP is a relatively common disease, with a large, larger than albumin, the a - and the prevalence of approximately 5–10 cases per b -globulins. The most important g -globu- 100,000 population. In CIDP as in AIDP, plasma lins are the immunoglobulins, the antibody exchange and IVIg are effective [8 ] . Additionally molecules produced by the highly special- in CIDP, in contrast to AIDP, corticosteroids are ized B lymphocytes called plasma cells. effective. In patients with CIDP, the challenge is A monoclonal gammopathy occurs when a the appropriate diagnosis, since many patients single plasma cell clone is overproducing can be misdiagnosed and treatment is thus one specifi c immunoglobulin. delayed. The natural history of CIDP is variable; Proteins in serum are measured by labo- some patients, the minority, respond to initial ratories using a serum protein electrophore- treatment and achieve complete remission, while sis (SPEP), in which the proteins are the majority of patients relapse or progress and separated by size and the information require prolonged treatment [9 ] . 11

Neuropathy Associated with Monoclonal Gammopathy 99 (MAG). MAG (Inset 9 .4 ) is a protein found in d isplayed on a curve in which the y -axis both the CNS and the PNS myelin and is a mem- represents amount of protein and the x -axis ber of the family of proteins called the immuno- represents size. The lowest-sized protein globulin superfamily (IgSF). The mechanism by peak is albumin, containing the largest which a high titer anti-MAG antibody might pro- amount of protein, while the g -globulins duce a neuropathy has not been worked out, but have a broad peak representing the diversity MAG is thought to be an important molecule for of billions of different molecules of various interactions between myelin and the axon. large size. In the abnormal SPEP from a patient with a monoclonal gammopathy, the albumin, a - and b -globulin peaks are nor- mally shaped, but the g -globulin region has Inset 9.4 MAG: A Member of the a large uniform peak representing an Immunoglobulin Superfamily M-protein, sometimes called M-gradient, a MAG is a 100 kDa protein in the myelin monoclonal protein. If the presence of the sheath near axons, mostly present in non- M-protein is not associated with any known compacted myelin, and is thought to pos- disease, the fi nding is called monoclonal sibly function in interactions between glia gammopathy of unknown signifi cance or and axons in both the CNS and the PNS. MGUS; frequently, an M-protein is found in It is a member of the immunoglobulin cases of the plasma cell malignancy called superfamily, sometimes abbreviated IgSF, multiple myeloma. In patients with the neu- because the members of the family bear ropathy associated with monoclonal gam- structural homologies to immunoglobulin, mopathy, it is believed that the M-protein especially the presence of immunoglobulin has reactivity to a component of nerve and, domains resembling the Fab portion of by binding to it and activating downstream immunoglobulins. Most members of the immune effectors such as macrophages, the IgSF are associated with the immune M-protein results in nerve injury. response, such as cytokine receptors, adhe- sion molecules, and proteins involved in the major histocompatibility complex. MAG on glial cells is an inhibitor of There are interesting subgroups within these neurite outgrowth presumably through disorders. For instance, a very high percentage of binding to a variety of receptors on neural patients with the osteosclerotic form of multiple cells such as p75, a nerve growth factor myeloma develop neuropathy. In addition, some receptor, or carbohydrates on the neural of these patients develop a syndrome called surface. The IgM from patients with mono- POEMS, in which the P (peripheral neuropathy) clonal gammopathy and neuropathy which and M (monoclonal gammopathy) are also asso- binds to MAG also binds to other molecules ciated with organomegaly (O), endocrinopathy that share carbohydrate epitopes with MAG (E), and skin changes (S). Most patients with such as P0, PMP-22, and glycolipids such neuropathy and MGUS have a sensory neuropa- as sulfate-3-glucuronly paragloboside thy called distal acquired demyelinating sensory (SGPG). At this time, it is unknown which neuropathy (DADS), which is very slowly pro- of the above target molecules may be criti- gressive and associated with minimal weakness. cal for the neuropathogenicity of the In a large percentage of DADS patients with IgM M-protein in patients with neuropathy and gammopathies, the paraprotein reacts with the monoclonal gammopathy. myelin protein, myelin-associated glycoprotein 100 9 Guillain–Barré Syndrome (GBS) and Other Immune-Mediated Neuropathies peripheral nerve myelin such as P , P , and PMP 12 Experimental Neuritis 0 2 22 have been the standard immunogens but glycolip- ids, particularly gangliosides, have also been used. EAN was fi rst described by Byron Waksman and Gangliosides are complex glycolipids, nonpro- Raymond Adams in 1955 when they immunized tein compounds which contain carbohydrates rabbits with homogenized peripheral nerves and linked to lipid molecules, with negatively charged found the animals developed neuritis. EAN can oligosacchrides and one or more sialic acid resi- be induced in a variety of animals by immuniza- dues. Many different models of autoimmune neu- tion with any number of peripheral nerve compo- ritis have been described based on immunity to nents, including whole peripheral nerve myelin gangliosides, but none has proven suffi ciently or the peripheral myelin proteins P , P , and 0 2 reproducible and robust to be used extensively. PMP . Susceptible animals have been the mouse, 22 A particularly intriguing ganglioside immunogen guinea pig, and rabbit, but the most commonly has been sulfated glucuronyl paragloboside utilized animal is the rat, usually the Lewis rat. (SGPG), which has been used as an immunogen Within 7–14 days after immunization, animals to induce neuropathy in rabbits, rats, and cats become weak, presumably from segmental demy- [ 10, 11 ] . The most convincing ganglioside antigen elination. This damage is thought to be due to linking experimental to human disease is G1Qb. anti-myelin T-cell responses, mostly in the nerve Antibodies to this ganglioside have been found in root, associated with both infi ltrating and a large percentage of patients with the Miller endoneural resident macrophages. As in EAE, Fisher variant of GBS, and Halstead et al. [6 ] have EAN is a monophasic event and animals recover described in vitro and in vivo models of neuropathy after the acute event, similar to GBS. Some mod- induced by a monoclonal anti-G1Qb antibody. els can be transferred with “neuritogenic” T cells Models of anti-ganglioside immune-mediated in a manner similar to the transfer of EAE with appear to be dependent on anti-ganglioside anti- “encephalitogenic” T cells, and it is thought that body, often IgM, and complement, rather than Lewis rat EAN is primarily T-cell-mediated. being T cell mediated. Gangliosides other than Cells and large molecules infi ltrating into nerve SGPG and G1Qb can be targets of immune must pass through a barrier called the blood– attacks, but the participation of any particular nerve barrier (BNB), which is similar conceptu- ganglioside in immune-mediated neuropathies ally to the blood–brain barrier. Demyelinating appears to be at least partly due to their accessibil- forms of EAN can also be caused by “bystander ity in vivo to circulating pathogenic antibodies; demyelination,” e.g., an immune response to many ganglioside are cryptic antigens, i.e., not ovalbumin, an irrelevant antigen, within the expressed on the surface of nerve. nerve; i.e., in an ovalbumin-sensitized mouse, There are fewer investigators working on EAN injection of ovalbumin into the nerve can induce than EAE for at least two reasons. First, infl am- a local experimental neuritis. Cell adhesion mol- matory neuropathies in humans are less common ecules, chemokines, matrix metalloproteinases, and less debilitating generally than is multiple cytokines, macrophages, antimyelin antibodies, sclerosis, so the pressure for translational research complement, and possibly Schwann cells are also is less. Second, EAN and ganglioside-mediated all thought to contribute to full expression of neuropathies are most easily induced in rats or EAN. After monophasic weakness, recovery rabbits, not mice, and thus the wealth of mutant follows usually occurring over a few weeks, pos- mice available for research in EAE is not as eas- sibly related to apoptosis, programmed cell death, ily accessible to EAN researchers. The latter of infi ltrating T cells. problem has been recently attempted to be T he precise molecules targeted by the immune addressed by a few researchers who have induced attack in various immune-mediated neuropathies experimental neuropathies in mice. has been a subject of intense study. Proteins of References 101 mediated neuropathy in a murine model. Brain. May References 2008;131(Pt 5):1197–208. 7. Koski CL, Baumgarten M, Magder LS, et al. 1. Ho TW, Mishu B, Li CY, et al. Guillain-Barre Derivation and validation of diagnostic criteria for syndrome in northern China. Relationship to chronic infl ammatory demyelinating polyneuropathy. Campylobacter jejuni infection and anti-glycolipid J Neurol Sci. 2009;277(1–2):1–8. antibodies. Brain. 1995;118(Pt 3):597–605. 8. Eftimov F, Winer JB, Vermeulen M, de Haan R, van 2. McKhann GM, Griffi n JW, Cornblath DR, Mellits Schaik IN. Intravenous immunoglobulin for chronic ED, Fisher RS, Quaskey SA. Plasmapheresis and infl ammatory demyelinating polyradiculoneuropathy. Guillain-Barre syndrome: analysis of prognostic Cochrane Database Syst Rev. 2009(1):CD001797. factors and the effect of plasmapheresis. Ann Neurol. 9. Barohn RJ, Kissel JT, Warmolts JR, Mendell JR. Apr 1988;23(4):347–53. Chronic infl ammatory demyelinating polyradicu- 3. McKhann GM, Cornblath DR, Ho T, et al. Clinical loneuropathy. Clinical characteristics, course, and and electrophysiological aspects of acute paralytic recommendations for diagnostic criteria. Arch Neurol. disease of children and young adults in northern 1989;46(8):878–84. China. Lancet. 1991;338(8767):593–7. 10. Yu RK, Usuki S, Ariga T. Ganglioside molecular 4. van der Meche FG, Schmitz PI, Dutch Guillain-Barre mimicry and its pathological roles in Guillain-Barre Study Group. A randomized trial comparing intrave- syndrome and related diseases. Infect Immun. Dec nous immune globulin and plasma exchange in 2006;74(12):6517–27. Guillain-Barre syndrome. N Engl J Med. 1992; 11. Ilyas AA, Gu Y, Dalakas MC, Quarles RH, Bhatt S. 326(17):1123–9. Induction of experimental ataxic sensory neuronopa- 5. Hughes RA, Raphael JC, Swan AV, van Doorn PA. thy in cats by immunization with purifi ed SGPG. Intravenous immunoglobulin for Guillain-Barre J Neuroimmunol. Jan 2008;193(1–2):87–93. syndrome. Cochrane Database Syst Rev. 2006(1): 12. Logina I, Donaghy M. Diphtheritic polyneuropathy: a CD002063. clinical study and comparison with Guillain-Barre 6. Halstead SK, Zitman FM, Humphreys PD, et al. syndrome. J Neurol Neurosurg Psychiatry. Oct Eculizumab prevents anti-ganglioside antibody- 1999;67(4):433–8. Neuromuscular Neuroimmunological Diseases: 10 Myasthenia Gravis the clinical symptoms. This ultimately results in 1 Defi nition a loss of AChRs and a pathological simplifi cation of the complex frond-like architecture of the Myasthenia gravis (derived from “my”-muscle, postsynaptic muscle membrane as shown in “asthenia”-weakness, and “gravis”-severe) is a Fig. 10.1 . neuromuscular disease whose clinical hallmark is The particular type of AChR targeted by anti- fatigable muscle weakness caused by autoanti- bodies in the serum of MG patients is the skeletal bodies to proteins at the neuromuscular junction muscle nicotinic AChR. This form of the AChR (NMJ). is distinct from AChRs present in the central ner- vous system, which consist of both nicotinic and muscarinic receptors with different structures. 2 Etiopathogenesis The nicotinic AChR is an oligomeric membrane protein, found in the normal adult almost exclu- The NMJ is a highly specialized anatomical inter- sively at specialized areas on muscle membranes section between motor nerves and muscle and called NMJs, which are adjacent to axonal termi- contains the motor nerve terminal, a space nals. The protein consists of fi ve subunits, two between the terminal and the muscle, and a com- alpha, and one each of beta, gamma, and epsilon plex section of the muscle membrane containing subunits. It functions as a ligand-gated ion chan- a number of proteins not present at other parts of nel. The release of adequate acetylcholine (ACh) the muscle. The pathogenesis of most forms of at the axon terminals, diffusion across the NMJ, myasthenia gravis (MG) is an antibody-mediated and binding to the AChR in the postsynaptic attack on the acetylcholine receptor (AChR). membrane results in an action potential in the These antibodies cause impaired function of the muscle; this is impaired in MG by the anti-AChR AChR and thus the NMJ, leading to fatigable antibodies. The impaired function of AChRs at weakness. It is likely that at least three different the end plate is responsible for the symptoms in mechanisms account for the damage. One is MG patients. complement-dependent lysis of AChRs, another Under normal conditions there is a balance is cross-linking of receptors and subsequent between the continued release of ACh from the degradation, and the third is direct blockade of presynaptic terminal and destruction of ACh the ion channel. Most patients with severe MG within the NMJ by an enzyme called acetyl- have a combination of all three mechanisms, cholinesterase. Acetylcholinesterase is a critical although most investigators feel that complement- molecule for neuromuscular transmission since dependent lysis leading to loss of AChR numbers ACh, once released into the NMJ, is destroyed is the predominant mechanism responsible for quickly if it does not bind to the AChR. A.R. Pachner, A Primer of Neuroimmunological Disease, 103 DOI 10.1007/978-1-4614-2188-7_10, © Springer Science+Business Media, LLC 2012 104 10 Neuromuscular Neuroimmunological Diseases: Myasthenia Gravis Fig. 10.1 Three mechanisms by which autoantibodies to a receptor cause loss of the channel from the surface. Loss of AChRs and change in muscle membrane in myasthenia gravis Increased ACh

at the NMJ, achieved by inhibiting is used not only for identifying the pathology of acetylcholinesterase, sometimes will improve MG in muscle biopsies but also in the immuno- NMJ function to make up for lost AChRs, which assay for the characteristic autoantibody (see is the basis for acetylcholinesterase inhibitors Sect. 8 ). Other snake toxins such as cobratoxin used in the diagnosis and treatment of MG (see are also used in AChR and MG research (see Inset below). Conversely, too much ACh is harmful 10.1 , Animal toxins in neurological research). since it can lead to desensitization of the AChR and weakness or paralysis. Inset 10.1 Animal Toxins in Neurological Disease, Including Conotoxin 3 Pathology Much of the publicity for animal toxins in neurological disease has been on toxins N eurologists and neuropathologists of the late from snakes such as the Indonesian many- nineteenth and early twentieth centuries were banded krait (bungarotoxin from Bungarus mystifi ed by the disparity between the profound multicinctus ) and cobra (cobratoxin from clinical symptoms and signs in MG and the Naja naja ) which bind to the nicotinic absence of pathological fi ndings that would AChR, or the mamba (dendrotoxin from explain them. Many patients did die of the dis- Dendroaspis ) which binds to voltage-gated ease, hence the name gravis, from the Latin for potassium channels. However, toxins from “weighty, serious, or heavy,” so there was no snails, spiders, and wasps are up-and-comers. shortage of autopsy material. Occasionally, Omega-conotoxin is the fi rst non-snake pathologists would see collections of lympho- toxin to be used extensively in a clinical cytes in muscle, called lymphorrhages, but these setting, as a probe for VGCCs to detect the were neither sensitive nor specifi c for the disease. anti-VGCC antibodies in LEMS. Cone It was not until the link to the AChR was clear, snails prey on other animals including fi sh and pathologists could use specifi c probes for the and use their toxins to immobilize their AChR, that it was clear that myasthenics had prey. They use a specialized form of tooth, markedly decreased AChR at the NMJ. called a toxoglossan radula, as a barbed The specifi c probe used in labeling the AChR harpoon which has the conotoxins in chan- is bungarotoxin, a toxin produced by the nels. Omega-conotoxin is not only used in Indonesian krait B ungarus multicinctus , which the anti-VGCC antibody assay but also is binds nearly irreversibly to the AChR. This toxin 5 Clinical Manifestations 105 the model for the chemically produced Inset 10.2 28-Year-Old Woman with Fatigue, drug, Ziconotide, which is FDA approved Misdiagnosed as Having Lyme Disease for intrathecal use for the treatment of This 28-year-old mother of two had been to pain. Spiders have a number of toxins. many doctors for severe fatigue, usually at Atracotoxins operate by opening sodium night, and occasional problems with speech channels while agatoxins from the funnel and swallowing. She came to UMDNJ web spider (A gelenopsis aperta ) have a because of our expertise in Lyme disease to number of effects on various ion channels. confi rm the diagnosis of Lyme disease which had been made by a community physician. She had no clinical manifesta- tions of Lyme disease, but one of many 4 Genetics and Epidemiology blood tests had been borderline positive. She had undergone extensive intravenous There are no known genetic proclivities for this antibiotic therapy for Lyme disease without disease, except that the disease is associated with clear benefi t. As she told her story, her other autoimmune diseases and frequently runs speech became more and more slurred. in families in which other members have other After a few minutes of rest, her speech was autoimmune conditions such as systemic lupus normal, but then slurred again as she spoke erythematosus, thyroiditis, rheumatoid arthritis, more. The diagnosis of MG was enter- or ankylosing spondylitis. tained, then confi rmed, and treatment When the disease begins in young individuals, resulted in complete resolution of her it mostly occurs in females, and is usually associ- symptoms. She has been symptom-free, ated with thymic hyperplasia, a condition in except for occasional mild fl ares of trouble which the thymus (see Chap. 1 ) is enlarged. The with speech, for 10 years with treatment link between thymic hyperplasia and MG remains mostly with cholinesterase inhibitors. unexplained. MG is increasingly being diagnosed in people over 50, in patients with a high inci- dence of thymic neoplasms, mostly benign, called thymomas. Patients with thymomas frequently have autoantibodies to other muscle proteins, examination might change a number of times such as titin and the ryanodine receptor. There through the day, depending on the prior use of may be some geographic peculiarities to MG involved muscles. Some muscles are commonly epidemiology. Zhang et al. [ 1 ] reported a high involved, such as the extraocular muscles (EOMs), incidence of childhood MG in China’s Hubei facial muscles, muscles of speech and swallow- province. ing, or proximal muscles of the arm or leg, while distal muscles are less frequently involved. Thus, common symptoms are double vision, drooping 5 Clinical Manifestations eyelids, slurred speech, diffi culty combing hair, or walking upstairs. All of these symptoms The hallmark of MG is fatigable muscle weak- worsen with repetition. Thus, a patient may start ness (see Inset 1 0.2 , a 28-year-old woman with out speaking a few sentences normally, but as the fatigue, misdiagnosed as having Lyme disease). speech extends to more than a few seconds, slur- Sustained effort in an involved muscle results in ring begins. Patients tend to be more symptom- decreased ability of the muscle to contract, but atic at night, as their muscles fatigue during the after rest the muscle might be able to function day, and they can appear relatively normal in the normally for a short time before it begins to morning. Since patients frequently see physicians fatigue again. Thus, a myasthenic patient’s during the morning hours, MG patients will 106 10 Neuromuscular Neuroimmunological Diseases: Myasthenia Gravis frequently be initially diagnosed as having sensitive electromyographic testing is performed. depression, hysteria, or malingering. Another method of classifying is by age: early- Most of the time the symptoms are chronic or onset MG is primarily seen in females and is subacute, fl uctuating, and unpredictable. associated with thymic hyperplasia, late-onset Occasionally, usually with an infection or associ- MG being seen equally in both sexes and associ- ated with surgery, patients experience a myas- ated with a high incidence of thymomas. thenic crisis, in which the symptoms exacerbate Increasingly, neurologists are also classify- rapidly and deterioration can be severe and life- ing the patients on the basis of the autoanti- threatening. During these crises, maintenance of body population involved. Those who do not swallowing and respiration is critical, and patients have detectable antibodies to AChR by the usually need to be monitored in an intensive standard immunoprecipitation assay are called care unit. “seronegative”, but frequently have autoanti- bodies, detectable in serum, to proteins at the NMJ other than AChR. The most frequent 6 Natural History and Prognosis autoantigen targeted by antibodies in seronega- tive MG is muscle-specifi c kinase (MuSK). The natural history of MG is highly variable. Anti-MuSK antibody-positive patients have a Some patients, especially those with the ocular different MG phenotype, with more facial form, are inconvenienced by the disease, but not involvement, both clinically and by electro- signifi cantly disabled. In contrast, patients with myographic testing. Sometimes facial muscle severe generalized MG, especially if the weak- atrophy is evident. In addition, the thymus ness involves muscles of swallowing and breath- tends not to be enlarged in MuSK antibody- ing, can have an unremitting course over months positive patients. Some seronegative patients to a few years with severe disability and ulti- may actually be seropositive but require more mately death from respiratory weakness, infec- sensitive assays available in the research lab to tions, or aspiration pneumonia. It is generally detect anti-AChR antibodies [2 ] . believed that the fi rst 5 years of the disease tend to be the most dangerous and if the neurologist can get the patient through that period, the 8 Diagnosis remainder of the course is not progressive. This is in dramatic contrast to multiple sclerosis (see The diagnosis of MG is made by history, exami- Chap. 4 ), the most common neuroimmunological nation, and laboratory testing. The most charac- disease, in which the disease course is progres- teristic symptom is excessive fatigability, in which sive, and most disability accrues after the patient muscle strength initially is normal, but fades very has had the disease for 5 years. quickly with use (see Inset 1 0.2 ). This is a helpful symptom for the diagnosis because it is relatively specifi c. In most other neurological diseases 7 Classifi cation affecting motor strength, weakness is present from the onset of muscle use. Most patients with The disease has been divided into “ocular” myas- MG have ocular symptoms. The examination can thenia and generalized myasthenia. Ocular be remarkably normal when the well-rested myasthenics have symptoms limited to their eye patient is seen in the morning; in this feature of movements, with ptosis (eyelid drooping) and profound fatigability, the disease is relatively dis- diplopia (double vision). The distinction is not tinct from other diseases affecting the nervous complete, since most generalized patients have system. There is no signifi cant sensory dysfunc- ocular symptoms and signs, and most ocular tion in MG, and deep tendon refl exes are usually myasthenics have subclinical involvement of normal, or even brisk. Thus, many features of the many other muscles that can be detected when exam are normal. 8 Diagnosis 107 Fig. 10.2 Repetitive stimulation of muscle in normal individuals (u pper level ) and those with myasthenia gravis (l ower level ) Objective fi ndings of fatigable weakness can nations are normal. When the diagnosis of MG is sometimes be elicited on examination. Many in the differential, the electromyographer will, in patients with MG have diffi culty with sustained addition to routine tests, also perform repetitive upgaze or tonic deviation of the eyes and develop stimulation to test transmission through the NMJ. ptosis (lid drooping) or an extraocular movement Repetitive stimulation at 3–5 Hz, will demon- palsy when these maneuvers are performed. strate a “decremental response” (Fig. 1 0.2 ). However, this takes patience by both the exam- At this rate of stimulation in normal individuals, iner and patient, since the weakness sometimes the compound muscle action potential (CMAP) takes a minute or two to be manifested. Since hot amplitude is the same for each stimulation, as temperatures exacerbate and cold temperatures shown on the left of the fi gure. In the myasthenic, ameliorate the weakness, an ice cube applied to a in contrast, as shown on the right of the fi gure, weak levator palpebrae muscle will sometimes the initial CMAP amplitude is normal, but subse- reverse ptosis. Another test that has historically quent potentials are lower and lower. been done at the bedside for MG, the Tensilon In generalized MG, most patients have detect- test, is no longer feasible because of lack of com- able anti-AChR antibodies in their blood. The mercial availability of Tensilon. In this test, edro- anti-AChR antibody assay is one of the few tests phonium, a short-acting acetylcholinesterase in neuroimmunology that has a nearly 100% inhibitor, was injected intravenously, resulting in specifi city. Patients with a positive test have MG a prompt temporary improvement of symptoms. nearly 100% of the time and there are only very The use of acetylcholinesterase inhibitors will be rare false positives. The test is said to be 85% discussed in Sect. 9 below. sensitive in generalized MG and 50% sensitive in M ost neurologists will utilize electromyogra- ocular MG, meaning that the test is false-negative phy/nerve conduction (EMG/NCV) testing as an 15 and 50% of the time, respectively. Other adjunct in the diagnosis of neuromuscular disor- autoantibodies also frequently found in MG ders, and MG is no exception. However, routine patients include anti-muscle antibodies, primar- testing will not demonstrate abnormalities since ily to myofi brillar proteins such as actin, myosin both nerve conduction and routine muscle exami- or titin, antithyroid antibodies, and antibodies 108 10 Neuromuscular Neuroimmunological Diseases: Myasthenia Gravis to voltage-gated potassium channels. These ful in moderately to severely

affected patients to antibodies are not commonly used in clinical improve symptoms. The risk/benefi t ratio of each practice. these agents must be carefully assessed, since Given the above distinctive clinical features none of these therapies is benign. and the multitude of diagnostic aids, the compe- One of the most aggressive therapies utilized tent neurologist will rarely err in diagnosing MG. in MG is surgical removal of the thymus. The In patients with early or mild disease when the rationale for thymectomy is that the thymus is symptoms are transient and the anti-AChR anti- usually abnormal in MG, and removal will ame- body negative, the diagnosis may be diffi cult. liorate the disease. Although this sounds logical, Some primary muscle diseases, such as unusual the evidence for benefi t is not strong, and the dystrophies or polymyositis (see Chap. 11 ), can potential risks of major thoracic surgery in be mistaken for MG, as can the Lambert–Eaton patients with MG are signifi cant. The complexi- syndrome (see below). Some acute poisonings, ties in consideration of this therapy in MG have such as with diphtheria or botulinum toxin, curare, been recently reviewed [3 ] . snake bites especially cobras or kraits, can be con- fused with myasthenic crisis, not surprisingly since a number of these also target the AChR. 10 Lambert–Eaton Myasthenic Syndrome 9 Therapy In Lambert–Eaton myasthenic syndrome (LEMS), patients present with weakness but it is distributed Treatment for ocular myasthenia can be directed differently than in MG, with trunk and leg involve- at the symptoms, such as patching one eye or sur- ment dominant, and ocular muscles only very gery to keep eyelids raised, without incurring the rarely involved. In contrast to MG, symptoms are risks and adverse effects of systemic therapy. frequently worst in the morning upon awakening Many myasthenics chose to utilize life-style and improve with exertion. This pattern is also changes, such as focusing activity early in the demonstrated by electromyography, in which day and incorporating many rest periods. The there is initially a small action potential which safest form of pharmacological therapy is the use increases with continued stimulation (see of anticholinesterases, the most popular of which Fig. 1 0.3 ). The defect is the inability to release is pyridostigmine. However, anticholinesterases enough packets of ACh. Most patients with LEMS are toxic if taken at too high a dose and the opti- are middle-aged or elderly, in contrast to MG. mum dose varies from one patient to the next. Patients with LEMS usually have diminished deep A s with the Guillain–Barré syndrome (dis- tendon refl exes. About 50% of LEMS patients cussed in Chap. 9 ), the most dramatic improve- have small-cell lung cancer but other cancers are ment in the mortality of MG occurred with the also associated. LEMS associated with cancers, widespread use of ventilators and intensive care like other paraneoplastic neurological syndromes units to provide respiratory support during the (see Chap. 14 ) can present prior to the identifi ca- times of myasthenic crises. Because of these tion of the malignancy. All individuals who pres- advances, MG is rarely a fatal disease today. ent with LEMS should be carefully evaluated for A range of immunotherapies has been utilized, the presence of a cancer, since about 60% of including corticosteroids, azathioprine, cyclo- patients with LEMS have an associated cancer. phosphamide, cyclosporin A, and mycophenolate, In the majority of LEMS patients, there are which are reviewed in Chap. 19 . IVIg and plasma- autoantibodies to presynaptic voltage-gated cal- pheresis are also used, frequently just prior to sur- cium channels (VGCCs). These are detected by gery in MG patients to minimize the autoantibodies. an immunoassay similar to that for MG, but a dif- None of these has been curative, but all are help- ferent toxin: omega-conotoxin from the marine 12 Experimental Models of MG 109 Fig. 10.3 Repetitive stimulation of muscle in a patient with LEMS cone snail, which binds with very high affi nity to decreased fetal movement, a condition called VGCCs, is used to label the target protein (see arthrogryposis multiplex congenita; arthrogry- Inset 1 0.1 ). Thus, the diagnosis of LEMS can posis can also be caused by neonatal neuromus- usually be made on the basis of the characteristic cular diseases other than MG. Improvements signs, symptoms, and electromyography and over the years in diagnosing and treating MG confi rmed with the demonstration of autoanti- have made neonatal MG and arthrogryposis bodies to the VGCCs. Many different types of multiplex congenita less common. treatment have been anecdotally tried in this rare condition, but the prognosis is determined by the underlying malignancy in the majority of LEMS 12 Experimental Models of MG patients. EAMG (experimental autoimmune myasthenia gravis) is one of the animal models in neuroim- 11 Neonatal MG and munological disease most faithful to the human Arthrogryposis Multiplex condition, because the pathogenic entity in both Congenita the human and animal entity has been defi nitively demonstrated to be the same: a polyclonal popu- Rarely, babies born to mothers with MG develop lation of anti-AChR antibodies. In EAMG, this muscle weakness, presumably due to the pla- population is usually elicited by immunization cental transfer of maternal anti-AChR antibod- with a purifi ed form of AChR, usually obtained ies. Why this happens so infrequently in from the specialized electric organ of electric eels myasthenic mothers is unknown. Occasionally, such as the Pacifi c electric ray, Torpedo califor- babies with neonatal MG are born to women nica. The electric organ of these animals, which with preclinical MG, i.e., women who have anti- the animals use to stun and paralyze their prey, is AChR antibodies but were asymptomatic. Some highly enriched in AChRs. AChRs purifi ed from women with MG, especially those with high electric rays were the fi rst neurotransmitter recep- levels of antibodies to fetal AChR, deliver babies tors to be isolated and sequenced. who are still-born or extremely weak, with fi xed In the induction of EAMG, the electric organs joints and other problems resulting from of these animals is homogenized and then passed 110 10 Neuromuscular Neuroimmunological Diseases: Myasthenia Gravis over a column in which the purifi ed AChR- interfere with AChR function, and thus it is not binding toxin from the king cobra N aja naja is surprising that levels of anti-AChR antibodies do bound. Once the AChR binds to the cobratoxin not predict disease severity. The target molecule the nonbinding material is washed off, and the is so large that an antibody could bind without pure AChR can be eluted from the column. necessarily affecting function. Experimental animals (mice, rats, or rabbits) can In 1970s and 1980s, we saw a tremendous then be immunized with the eel AChR. After a explosion of knowledge about the AChR and its time, often with boosting immunizations, the ani- role in EAMG. With this wealth of understand- mal’s immune response against the eel AChR ing, down to the molecular confi rmation of the begins to cross-react with the animal’s own targets of the pathogenic antibodies, one might AChRs leading to the development of myasthenic have predicted that it would not be too diffi cult to weakness. Although weakness in the experimen- utilize this information toward therapy. Some tal animals is due to the action of anti-AChR anti- promising efforts toward that end in EAMG have bodies at the NMJ, T cells specifi c for the AChR been recently summarized [4 ] . Unfortunately, are required to help the B cells make antibody at new therapies based on this information have not adequate levels and with adequate affi nity for the been developed, and the current therapy remains AChR. Using this approach in mice, monoclonal nonspecifi c, broad spectrum immunosuppression anti-AChR antibodies could be generated, which of the whole immune response rather than a has aided in understanding AChR function. “smart bomb” targeted to a specifi c part of the A particularly important area in the AChR AChR molecule. The reasons for this are com- molecule is the main immunogenic region (MIR), plex, but a contributing factor is that MG is rela- an identical portion of each of the two alpha sub- tively a small market, and pharmaceutical units in each AChR. A substantial portion of the companies may not be willing to make a large anti-AChR antibodies in human and experimen- investment in research and clinical trials. tal MG bind to the MIR, which is a conforma- tion-dependent region. The MIR is angled outward from the central axis of the AChR, and References thus a single anti-AChR IgG antibody cannot 1. Zhang X, Yang M, Xu J, et al. Clinical and serological crosslink the two subunits within a single mole- study of myasthenia gravis in HuBei Province, China. cule of AChR, but does crosslink adjacent AChRs. J Neurol Neurosurg Psychiatry. Apr 2007;78(4):386–90. The MIR is distant from the ACh-binding site. 2. Brooks EB, Pachner AR, Drachman DB, Kantor FS. Thus, anti-MIR antibodies do not block ACh A sensitive rosetting assay for detection of acetylcho- line receptor antibodies using BC3H-1 cells: positive binding to the NMJ. The site on the AChR which results in ‘antibody-negative’ myasthenia gravis. binds ACh is the same as that which binds snake J Neuroimmunol. 1990;28(1):83–93. toxins, and when antibodies bind there, they tend 3. Richman DP, Agius MA. Treatment of autoimmune to be particularly pathogenic. Thus, it is likely myasthenia gravis. Neurology. 2003;61(12):1652–61. 4. Pachner AR. Antigen-specifi c immunotherapy in myas- that many of the anti-MIR antibodies in an anti- thenia gravis: failed promise and new hope. AChR antibody population do not markedly J Neuroimmunol. 2004;152(1–2):vii–viii. The Prototypic Neuroimmunological Muscle Disease: Dermatomyositis 11 acetylcholine receptor. Thus, it is not clear whether 1 Defi nition the autoantibodies in IIMs are pathogenic, or simply secondary biomarkers of the infl ammatory Dermatomyositis is a rare infl ammatory disease of activity in muscle. Myositis can also be associated muscle of unknown cause resulting in muscle with malignancies as a paraneoplastic syndrome; weakness and pain in young- or middle-aged peo- this is discussed in Chap. 14 . ple. It is a member of a category of diseases that can Some recent data implicates a population of be grouped together as idiopathic infl ammatory dendritic cells called plasmacytoid dendritic myopathies ( IIMs), the other members of which are cells (PDCs) as being important in the IIMs (see polymyositis and inclusion body myositis (IBM). Chap. 1 for a description of dendritic cells). These cells, when activated, produce large amounts of type I interferons, i.e., IFN- a and 2 Etiopathogenesis IFN-b . Biopsy specimens in patients with IIMs express large levels of interferon-induced genes The etiology is unknown but is assumed to be such as the human myxovirus resistance 1 pro- autoimmune because of the following combina- tein (MxA). The precise cause of the activation tion of characteristics. First, there is no other of PDCs in IIMs is unknown. explanation for the disease. Second, models resembling IIMs can be induced by immunization of animals with muscle proteins. Third, IIMs 3 Pathology respond positively to anti-infl ammatory medica- tions. Fourth, there are a number of autoantibodies Muscle biopsy reveals a mononuclear cell infi l- associated with dermatomyositis, which are trate which is usually in the perimysium, the divided into myositis-specifi c autoantibodies thicker fi brous tissue separating muscle bundles. (MSAs), seen only in myositis, and myositis- Degenerated muscle fi bers may be present. There associated autoantibodies, which can also be seen is atrophy of muscle fi brils at the edges of the in other autoimmune diseases. However, none of muscle fascicle, so-called perifascicular atrophy. the autoantibodies are found in the majority of In the related myositis, polymyositis, there is an patients, and the targets of these autoantibodies infl ammatory exudate present in a different part of are all intracellular molecules, many of which the muscle fi ber, the endomysium, the thin layer of are DNA-binding proteins. This is in contrast connective tissue around individual muscle fi bers. to myasthenia gravis where an autoimmune In IIMs, there can be invasion of nonnecrotic mus- pathogenesis is well-accepted, mediated by cle fi bers by mononuclear cells, or other areas of autoantibodies to extracellular portions of the infl ammation such as around blood vessels. A.R. Pachner, A Primer of Neuroimmunological Disease, 111 DOI 10.1007/978-1-4614-2188-7_11, © Springer Science+Business Media, LLC 2012 112

11 The Prototypic Neuroimmunological Muscle Disease: Dermatomyositis of corticosteroid therapy the mortality rate was as 4 Genetics and Epidemiology high as 50%. Corticosteroid therapy has greatly alleviated the disease burden of dermatomyositis There are many genetic causes of myopathy, i.e., and other infl ammatory myopathies. muscle disease, but the idiopathic infl ammatory myopathies (IIMs), i.e., dermatomyositis, poly- myositis, and inclusion-body myositis, do not 7 Classifi cation appear to have a genetic component. These are rare diseases, with an annual incidence of approx- The infl ammatory myopathies are usually divided imately 1 in 100,000. Most studies fi nd that more into dermatomyositis, polymyositis, and IBM. women than men have dermatomyositis and Most neurologists think of polymyositis as being polymyositis. identical to dermatomyositis, except without skin manifestations. This is reasonable, given the sim- ilarities in clinical presentation and in therapy. 5 Clinical Manifestations However, there are differences on muscle biopsy, and dermatomyositis is more frequently associ- T he usual patient with dermatomyositis is a ated with malignancies. In contrast, IBM appears young- or middle-aged individual who subacutely to be a somewhat different disease: the weakness develops symmetric proximal limb weakness. is more slowly evolving, selectively involves fi n- The patient also has a characteristic rash of the ger fl exors or quadriceps muscles, and usually cheeks and eyelids, called the heliotrope rash, appears in an older individual. CK levels may be which is pinkish purple, and often affects the normal in IBM, there are usually no associated face, eyelids, or hands. There can also be red, autoantibodies, and it is not generally responsive scaling papules on the knuckles, sometimes to corticosteroid therapy. IBM also has character- called Gottron’s papules. When disease is acute istic biopsy fi ndings not commonly found in the or severe, there can be muscle pain and tender- other two diseases. Some neuromuscular neurol- ness. Clinical suspicion for dermatomyositis is ogists consider IBM to be more of a degenerative confi rmed by elevation of the muscle enzyme, disease with the infl ammatory response being creatine kinase (CK), in the blood, as well as by secondary. However, recently Chahin and Engel characteristic fi ndings on electromyography. [ 2 ] have described patients who had muscle biop- Some patients also have involvement of muscles sies characteristic of polymyositis but had clini- of swallowing, leading to diffi culty with swal- cal features consistent with IBM. Because of lowing, also called dysphagia. A substantial per- these overlap syndromes and the importance of centage of myositis patients have pulmonary determining response to immunomodulatory involvement, called interstitial lung disease therapy, there have been increasing efforts over (ILD), which in some studies has identifi ed a the past decade to classify these diseases by their population of patients with a worse prognosis. molecular signatures. The infl ammatory myopathies can also be associ- ated with other infl ammatory diseases such as systemic lupus erythematosus (SLE), rheumatoid 8 Diagnosis arthritis (RA), or Sjogren’s syndrome. The diagnoses of polymyositis, dermatomyositis, or IBM are made on the basis of the characteristic 6 Natural History and Prognosis symptoms and signs, elevated muscle enzymes in the blood, a consistent pattern on electromyogra- The natural history and prognosis of this disease phy, infl ammation on the muscle biopsy, and are highly variable [ 1 ] . Most patients do poorly absence of other causes of myopathies or other without treatment, and prior to the development associated infl ammatory diseases, such as lupus, 10 Related Neuroimmunological Muscle Diseases 113 rheumatoid arthritis, mixed connective tissue d isease, or vasculitis. It is important to distin- guish the infl ammatory myopathies from nonin- fl ammatory myopathies such as dystrophies, metabolic myopathies especially hypokalemia and thyroid disease, or muscle disease due to mitochondrial abnormalities, since treatment of these conditions is different. S ome autoantibodies associated with infl am- matory muscle disease target a class of enzymes called aminoacyl-tRNA synthetases, which link a specifi c amino acid to transfer RNA. Antibodies Fig. 11.1 Trichinosis. Histologic section shows encysted to histidyl tRNA synthetases, also called anti- larvae of T . spiralis in skeletal muscle Jo-1, are the most common, but these are only seen in about a ¼ of myositis patients, while anti- bodies to the other aminoacyl transferases are seen in only 1–5% of patients. These autoanti- erythrocyte sedimentation rate (ESR), a test bodies, therefore, are not helpful clinically. of the blood which usually indicates an infl ammatory process. In about 10% of PMR patients, a blood vessel infl ammation called 9 Therapy temporal arteritis, also called giant cell arteri- tis, occurs. This can be a dangerous condi- The therapy most commonly used in dermato- tion, because it can occlude vessels to the eye, myositis is corticosteroids, especially oral pred- and cause blindness. PMR and temporal nisone. The usual dose for initiation of therapy is arteritis are highly responsive to corticoster- 60 mg/day which can be adjusted over time oid therapy and should be high on the list of depending on response to therapy or development the diagnostic possibilities of older patients of adverse effects. Corticosteroids have been very with persistent muscle pain. effective in the treatment of dermatomyositis and (b) Diseases of the neuromuscular junction: Other polymyositis. Therapy of IBM is more problem- neuroimmunological muscle diseases to be atic; no therapy has been shown to be consistently considered in the differential of patients with helpful. IIMs are neuromuscular junction diseases. Weakness is a hallmark of these diseases, such as myasthenia gravis and Lambert–Eaton 10 Related Neuroimmunological myasthenic syndrome; they are reviewed in Muscle Diseases Chap. 10 . Usually, the differences on history and examination between these diseases and (a) Polymyalgia rheumatica (PMR) is a relatively infl ammatory muscle diseases are clear, but common infl ammatory disease of unknown occasionally extensive laboratory studies are etiology, causing severe pain in muscles, usu- necessary to distinguish them. In addition, ally in older individuals. Weakness is not a there are infectious causes of muscle dis- common feature. Usually, the pain is in the ease, such as viruses (including HIV and neck, shoulders, or hips and is worse in the infl uenza), parasites (trichinosis—shown in morning. The diagnosis is made by the char- Fig. 11.1 —toxoplasmosis and cysticercosis), acteristic history, absence of other pathology, and even bacteria (such as staphylococcus). and confi rmed by the presence of a high These are relatively rare. 114 11 The Prototypic Neuroimmunological Muscle Disease: Dermatomyositis mouse models, in which mutant mice can be used 11 Experimental Models of to identify possible pathogenetic mechanisms. Infl ammatory Muscle Disease However, as of 2010, experimental models of infl ammatory muscle disease have not contrib- A variety of animal models of IIMs have been uted signifi cantly to understanding the pathogen- induced by immunization of experimental ani- esis of these diseases. mals, usually rats, with muscle homogenates or purifi ed components of muscle [3 , 4 ] In this model, called experimental autoimmune myositis (EAM), investigators have used a variety of skel- References etal muscle proteins, including the C-protein, laminin, and histidyl-tRNA synthetase. Most of 1. Mammen AL. Dermatomyositis and polymyositis: Clinical presentation, autoantibodies, and pathogenesis. the publications on the models represent “proof- Ann N Y Acad Sci. 2010;1184:134–53. of-principle” types of experiments in which 2. Chahin N, Engel AG. Correlation of muscle biopsy, immunizations with various components were clinical course, and outcome in PM and sporadic IBM. utilized simply to establish that these proteins Neurology. 2008;70(6):418–24. 3. Nagaraju K, Plotz PH. Animal models of myositis. could function as autoantigens to induce autoim- Rheum Dis Clin North Am. 2002;28(4):917–33. munity and injury. Within the past few years, some 4. Katsumata Y, Ascherman DP. Animal models in myosi- investigators have moved more aggressively into tis. Curr Opin Rheumatol. 2008;20(6):681–5. A Introduction to Neurological Infections: Neuro-infectious Disease 12 as Part of Neuroimmunology Neurological infections are an important part of spirochete was serendipitously identifi ed in neuroimmunology. The concepts and issues dealt ticks from Lyme-endemic areas by Dr. Willy with in the previous chapters have covered neuro- Burgdorfer, an entomologist. Serum from Lyme logical infl ammatory diseases that are considered arthritis patients was then shown to bind to these “autoimmune” primarily because no pathogen spirochetes, and the spirochetal etiology con- has yet been identifi ed. These diseases also have fi rmed in 1981 [ 1 ] . Since the rash of Lyme dis- relevance to neurological infl ammatory diseases ease was fi rst described by the Swedish in which pathogens have been identifi ed. The dermatologist Afzelius in 1909, it took 72 years nervous system has only a limited repertoire with and luck to fi nally identify it as an infectious dis- respect to infl ammation. Processes such as micro- ease. Thus, many neuro-infl ammatory syndromes glial proliferation, loss of blood–brain barrier which we now consider “autoimmune” or function, immune cell infi ltration into the CNS, “infl ammatory” may be infectious due to as yet have already been discussed and function simi- unidentifi ed pathogens. Their discovery as infec- larly in neurological infections as they do in auto- tions may simply be waiting for a serendipitous immune diseases. discovery similar to that of Dr. Burgdorfer. I n no fi eld of medicine is the statement, Neurological infections can be classifi ed in “Absence of evidence is not evidence of absence” many ways, including by: more relevant than in neuroimmunology and • Location within the nervous system (central neuro-infectious disease. The likelihood that nervous system—brain meninges, spinal cord many neuro-infl ammatory syndromes such as parenchymal vs. peripheral nervous system) MS and neurosarcoidosis are caused by patho- • Pace (acute/subacute/chronic), or gens seems high and the fact that pathogens have • Type of infectious agent (bacterial, viral, fun- not yet been identifi ed is not strong “evidence of gal, and other). absence” since our current tools for identifying This primer will utilize location, and, as in new infections in the CNS are not powerful. previous chapters, a prototypic disease will be A recent example of this diffi culty is Lyme dis- discussed for each of these: Lyme disease/neuro- ease. When Lyme arthritis was fi rst described, syphilis for involvement of meninges, herpes many rheumatologists were convinced that it simplex encephalitis (HSE) for involvement of was autoimmune since the pathology of the joints the “encephalon” (enkephalos in Greek means mimicked the pathology of rheumatoid arthritis, brain, literally “within the head”), and leprosy for all standard cultures of the joints were negative, infections involving the peripheral nervous sys- and no organisms were seen on joint pathology. tem. Other infections important for the neuroim- Initially, the disease was linked to ticks by munologist will be discussed with these as a epidemiological studies, and subsequently the backbone. A.R. Pachner, A Primer of Neuroimmunological Disease, 115 DOI 10.1007/978-1-4614-2188-7_12, © Springer Science+Business Media, LLC 2012 116 12 A Introduction to Neurological Infections… 1 General Rules of Neuro- holes into his skull with an electric drill to infectious Diseases “let the demons escape.” Three holes had already been drilled and a seizure had been 1.1 Infection of the Nervous System responsible for the loud sounds and the Follows Systemic Infection unresponsiveness. After 3 weeks of admis- sion to the neurosurgical unit for manage- Although infection sometimes appears fi rst most ment of his wounds, and treatment with dramatically in the nervous system and is what anticonvulsants, antipsychotics, and antibi- brings the patient to the attention of physicians, otics, the patient began complaining of neurological infection is almost always a conse- worsening headaches and a CT scan revealed quence of initial entry of the infection elsewhere, two abscesses which required excision. and subsequent spread to the nervous system. Frequently, in very ill hospitalized patients, Author’s note . This patient is an exception bacterial meningitis is a consequence of sepsis to the rule that systemic infection precedes associated with known infections such as pneu- CNS infection. Usually, the penetrating monias, abscesses, or urinary tract infection. head trauma is from motor vehicle acci- Severe infections contiguous to the CNS, such as dents. In this case, the patient was a victim sinusitis or otitis, can spread to the CNS. In CNS of self-injurious behavior. tuberculosis, CNS infection follows pulmonary involvement, and in Lyme disease, neurological involvement follows the dermatological process. 1.2 Neuro-infectious Diseases Frequently, though, in acute bacterial meningitis Should Be in the Differential in the community, meningitis is the fi rst sign of Diagnosis

in Many Patients the infection, although clearly the infection was with Diffi cult Neurological acquired systemically. The only true exception to Syndromes Because of Their this rule is after neurosurgical intervention or Reversibility with Antibiotics penetrating injuries to the CNS when bacteria are directly introduced (see Inset 1 2.1 ). In the USA, Europe, and other countries with a high level of public health and hygiene, CNS infections are not as common as in developing Inset 12.1 “ A 45-Year-Old Man with a Brain countries. Thus, neurologists frequently do not Abscess” consider CNS infections in the differential diag- nosis of neurological conditions despite the fact JT was admitted to the hospital from the ER that most infections are much more effectively with a seizure. Diagnosed with paranoid treated than many of the other diseases neurolo- schizophrenia in his late teens, he had been gists diagnose. This is illustrated in the patient in and out of mental institutions for most of described in Inset 1 2.2 , in which CNS toxoplas- his adult life, but had had been doing fairly mosis was not considered in the differential diag- well at home until a month prior to his nosis of a young man with right-sided weakness. admission when he refused to take his medi- cations because they “limited me.” For the week before admission, his parents with 1.3 Diagnosis by Identifi cation whom he lived had noted that he became of the Infectious Agent Is Ideal, increasingly agitated. On the day of admis- but Sometimes Impossible sion, intermittent loud sounds were coming from his upstairs bed room and when his Ideally, diagnosis in an infectious disease is made father investigated he found his son unre- by isolation of the pathogen from the patient. For sponsive, in a pool of blood, after drilling example, a bacterial meningitis is diagnosed by culture of the bacterium from the cerebrospinal 1 General Rules of Neuro-infectious Diseases 117 fl uid (CSF) of the patient. Until recently, the diag- Inset 12.2 “Right-Sided Weakness in a nosis of viral infection by isolation of the causative Construction Worker” virus was diffi cult, because of methodological A 31-year-old construction worker, mar- problems with virus cultures. The advent of poly- ried and father of two, presented to a merase chain reaction (PCR) testing has been a community neurologist in Newark, NJ, major advance for diagnosis of viral infections of with 4 months of malaise and mild right- the CNS. For example, in the past the diagnosis of sided weakness. He had had some diffi - progressive multifocal leukoencephalopathy culty with vision 3 years previously which (PML), a demyelinating CNS disease seen in immu- had resolved; he could not recall if this nosupressed patients and caused by the JC virus, involved one eye or both. Examination was only possible by brain biopsy. Now the diagno- confi rmed mild right proximal weakness sis is confi rmed, after suspicious clinical and MRI with mild hyper-refl exia on the right and a fi ndings, by positive PCR for JC virus in the patient’s right Babinski; there were no other abnor- CSF. Some organisms, such as Mycobacterium malities. MRI of the brain revealed a num- tuberculosis , the causative organism of tuberculo- ber of enhancing lesions, and the diagnosis sis, are notoriously diffi cult to diagnose by isolation of multiple sclerosis was made; the patient of the offending organism, and organisms present was offered IFN-b therapy. A lumbar punc- in the CSF of infected patients can take weeks to ture was not performed. The patient grow in culture. In other infections such as Lyme requested a second opinion and came to disease and neurosyphilis, the problems with iden- our University Hospital. The history and tifi cation of the infectious agent, either by culture or examination was as previously obtained PCR, are such that indirect methods, primarily except that the patient admitted to the use identifi cation of the specifi c antibody response, are of occasional intravenous drugs and pro- used. Reliance on serology, however, makes the miscuous sexual activity over the previous false-positive and false-negative rate in diagnosing 15 years. A review of the MRI revealed these infections higher than for other CNS infec- that the lesions were not typical of MS. An tions in which isolation of the infectious agent is HIV antibody assay was positive with a straightforward (see “Patient with myasthenia gravis high plasma viral load, and the CD4 count masquerading as Lyme disease” in Chap. 10 ). was low. Based on the brain MRI and the HIV positivity, a diagnosis of HIV/AIDS 1.4 Prompt Recognition of Curable with CNS toxoplasmosis, infection of the Infectious Diseases Is Critical brain with the parasite T oxoplasma gondii , was made and confi rmed by a treatment It is axiomatic that curable infectious diseases of trial, i.e., complete resolution of his the nervous system need to be diagnosed and headaches and MRI lesions by treatment treated as soon as possible, but that is frequently with pyrime thamine and sulfadiazine for easier said than done, especially if the index of 3 weeks. He was subsequently placed on suspicion for infection is low. Given the fact treatment with antiretroviral therapy that infection incidence is dependent on geo- (tenofovir/emtricitabine/efavirenz) with graphic area of exposure, a patient’s history of clearance of his plasma viral load. He did travel to regions far away from home is impor- well in follow-up. tant. However, a travel history is frequently not Author’s note . Many urban areas in the obtained by health care professionals, an omis- USA have quite high incidences of HIV/ sion in our highly mobile society that can result AIDS. Neurologists practicing in the area in an unfortunate delay in diagnosis and treat- must be aware of this problem and consid- ment. What is common in one area is very rare in ers opportunistic infections in the differen- another, and physicians generally think about tial diagnosis of neurological disease. diseases likely in their specifi c region not in other areas (see Inset 1 2.3 ). 118 12 A Introduction to Neurological Infections… Inset 12.3 “Headaches and Confusion in a that the patient was from NJ, a state highly Surgeon in New Jersey” endemic for that infection. However, the nega- I n the fall, this 51-year-old orthopedic surgeon tive tests for anti- B. burgdorferi antibody from NJ, father of three, developed headaches essentially ruled out that process, which the and mild confusion which forced him to cut community neurologist realized. His alterna- back on his practice. When his confusion tive diagnosis, primary CNS vasculitis, was worsened, he saw his primary care physician highly unlikely, given its rarity (see Sect. 5 in who drew blood work and referred him to a Chap. 13 ). Thus, initiating corticosteroid ther- local neurologist. Both physicians felt Lyme apy, which is an immunosuppressive, without disease was possible, and he was begun on more evidence for primary CNS vasculitis, an antibiotics for this infection. However, there extremely rare disease, was quite risky, espe- was no history of a skin rash and a Lyme blood cially without having thoroughly ruled out an test was negative. When symptoms worsened, infection. Coccidioidomycosis, caused by an MRI of the brain and an LP was performed. Coccidioides immites (Fig. 12.1 ), is a rela- The MRI revealed numerous, but nonspecifi c tively common infectious cause of subacute white matter changes, and the lumbar punc- meningitis in Arizona but exposure does not ture revealed mildly low glucose, elevated occur in the Northeast and Midwest USA, protein, and many white cells, mostly mono- while Lyme disease is a common infectious cytes. Lyme antibody testing in the CSF and cause of subacute meningitis in the Northeast serum was negative. Because of the white and Midwest USA, but exposure does not matter changes, the neurologist diagnosed occur in Arizona. probable CNS vasculitis and instituted high- dose corticosteroid therapy. The patient was less confused and generally felt better for a few days, but then became agitated, belliger- ent, confused, and then drowsy and poorly responsive. After transfer to a large metropoli- tan center and subsequent meningeal biopsy, the patient deteriorated further and died. The biopsy and CSF revealed culture positivity for Coccidioides immitis , the serum was positive for anti-Coccidiodal antibodies, and autopsy revealed disseminated fungal lesions. The wife provided the history, previously not obtained, that her husband had spent 2 weeks in a tennis camp in Arizona in the late spring of that year. It was felt by the clinicians caring Fig. 12.1 Coccidioides immitis . Arthrospores (myce- for him that earlier treatment, in conjunction lia) of C occidioides in culture. This mycelial phase of the organism is the form which grows in desert soil with avoidance of corticosteroids, could have and in the laboratory. These spores easily become been curative. aerosolized and are infectious; it is these spores which get inhaled and cause the disease. In the mammalian Author’s note . The initial diagnosis of possi- host, the fungus changes into another form, a ble Lyme disease was not unreasonable, given spherule 2 Lyme Meningitis: The Prototypic Meningitis 119 1.5 Therapy of Neuro-infectious The subacute spirochetal meningitides (neuro- Diseases Is Frequently More syphilis/Lyme disease) will be discussed with Diffi cult than Therapy of brief reviews of acute bacterial meningitides and Infections Elsewhere in the Body chronic meningitides. Some infections more commonly develop in the brain parenchyma, and As in many situations in which inherent in a sys- HSE will be described as a prototypic disease for tem’s unique strengths are also unique weak- such CNS infections. Next, leprosy will be dis- nesses, in the CNS the isolation from the systemic cussed as the prototypic peripheral nerve infec- circulation provided by the blood–brain barrier, tion. Finally, neurological infections characteristic which protects the CNS most of the time, also of HIV/AIDS will be discussed. results in diffi culties when trying to deliver anti- infective products to the CNS. Thus, most drugs injected intravenously only partially penetrate 2 Lyme Meningitis: The into the CNS. This is true even when the blood– Prototypic Meningitis brain barrier is partly opened by the infl ammation associated with the infection. This diffi culty with Most infections reach the CNS via the blood, delivery of antibiotics to the CNS applies to treat- and the blood vessels in the CNS traverse the ment of any infectious process within the CNS. meninges for a substantial distance before fi nally Sometimes if the infection is life-threatening and penetrating into the CNS parenchyma. The com- response to intravenously administered anti- plex anatomy of the meninges is shown in infectives is insuffi cient, the physician is forced Fig. 1 2.2 . CSF circulates in the subarachnoid to deliver them directly into the subarachnoid space, below the arachnoid and above the pia space using intrathecal injections. mater, in the space labeled “subarachnoid space.” Pathogens causing meningitis frequently are unable to pass through the pia mater, and the 1.6 Always Keep HIV/AIDS in Mind glial limitans, to enter the brain parenchyma in any large numbers and thus remain in the suba- Over a million individuals in the USA are rachnoid space. Thus, it is not suprising that infected with human immunodefi ciency virus meningitis is the most common form of neuro- (HIV) of which a large percentage are not aware logical infection. Almost any microorganism of their infection. In addition, a signifi cant per- can cause a meningitis. centage of individuals do not volunteer the fact that they are HIV-positive to health care profes- sionals. Thus, one must always consider the pos- 2.1 Defi nition sibility that a patient with a newly acquired neuro-infl ammatory syndrome may have HIV/ Lyme neuroborreliosis (LNB) results from infec- AIDS underlying their illness, since this diagno- tion of the nervous system by the spirochete sis increases the possibilities of a large number Borrelia burgdorferi . of infectious diseases not normally encountered in the immunocompetent patient. This book is not a neuro-infectious disease 2.2 Etiopathogenesis text; there are some excellent books which fi ll that bill [2 , 3 ] . Instead, relatively common, proto- Spirochetes are ideally suited for persistence in typic neuro-infectious diseases will be described. the human host. Although they are very fragile As in earlier chapters, the diseases will be outside of an animal, once inside they can survive discussed by

anatomic locations. Since most for prolonged periods. Unlike viruses, which infections fi rst encounter the nervous system via depend on rapid replication after entry into cells, the meninges, meningitis will be the fi rst topic. spirochetes are extracellular and have very slow 120 12 A Introduction to Neurological Infections… Fig. 12.2 Layers of the scalp, skull, and meninges. between the arachnoid membrane and the pia membrane Intracranially, the space between the skull and the dura is closely applied to the brain surface is the subarachnoid the epidural space, the space between the dura and the space. Cerebrospinal fl uid (CSF) fi lls the subarachnoid arachnoid membrane is the subdural space, and the space space rates of replication. Using a variety of means to seen using dark-fi eld microscopy and appear as escape the immune system, they are able to sur- helical, motile organisms about 10–25 m m in vive despite strong anti-spirochetal immune length (Fig. 12.3 ). responses. They are large microorganisms with There are a number of different subspecies of an associated large genome. B orrelia burgdorferi Borrelia burgdorferi which determine the type of has a genome of 1.4 million base pairs, while neurological involvement in LNB. The clinical Theiler’s virus, which induces a chronic infection phenotype of LNB in humans and in experimen- resembling MS in mice (see Chap. 8 ), in contrast tal models is determined by the genotype of the has a genome of only 8.1 thousand base pairs. infecting strain [4 ] . The whole species of B orrelia Only a very small percentage of B orrelia burg- burgdorferi is called Borrelia burgdorferi sensu dorferi ’s genome encodes for proteins which are lato; LNB in North America is caused by the characterized; the spirochete’s genome thus rep- sensu stricto strain of B orrelia burgdorferi , the resents a vast uncharted wilderness for molecular predominant form in North America, while LNB biologists. The most common spirochetal infec- in Europe is caused by either Borrelia garinii or tions in the USA and Europe are Lyme disease, Borrelia afzelii . In Lyme disease, spirochetes can caused by Borrelia burgdorferi , and syphilis, lodge anywhere where there is collagen and caused by Treponema pallidum . Spirochetes from connective tissue. These can include collagen some types of clinical specimens can be readily within the extracellular matrix in the meninges, 2 Lyme Meningitis: The Prototypic Meningitis 121 Fig. 12.3 Borrelia burgdorferi , dark-fi eld microscopy. Public Health Image Library (PHIL), with identifi cation The spirochetes are corkscrew-shaped and are 10–20 m m number #6631) long (from Centers for Disease Control and Prevention’s where fi broblasts are present, or in the connective and chronic infl ammation is a recurrent motif tissue around nerves, the perineurium. Thus, among chronic infections. these pathogens do not invade cells but survive around them. They may utilize the linear fi brils of collagen as a “hiding” place, to avoid immuno- 2.3 Clinical Manifestations surveillance by lymphoid cells [5 ] . They also avoid immune-mediated destruction by interfer- Lyme meningitis is the most common manifesta- ring with host complement. The infl ammation tion of LNB in the USA and usually presents a caused by these spirochetes thus tends to occur in few weeks to a few months after initial infection. the meninges and in peripheral nerves; neurons Patients experience symptoms of headaches, neck and oligodendroglia are not generally directly stiffness, numbness, and tingling without clear affected and thus permanent neurological dys- anatomical localization, muscle aches, fatigue, function or demyelination is generally not a fea- and malaise; these symptoms are generally mild ture of LNB. relative to the severe symptoms of meningitis A utoantibodies, especially in the CSF, appear caused by more aggressive bacteria such as commonly in LNB and other chronic infections. meningococcal or streptococcal meningitis. In one study, the frequency of intrathecal synthe- Sometimes, patients develop focal neuropathies sis of autoantibodies was 85% in LNB, compared or radiculopathies, but severe neuropathies with with 12% in multiple sclerosis and 55% in viral substantial motor weakness are unusual. Many meningo-encephalitis; intrathecal antibodies had patients early in the infection think they are sim- specifi city for more than 20 different CNS pro- ply depressed or overworked or sleep-deprived, teins, including myelin basic protein (MBP) and but later become more symptomatic, and come to three neurofi lament proteins [6 ] . Whether autoan- the attention of the physician. Many patients have tibodies contribute to pathogenesis in this and mild cognitive symptoms but not severe organic other chronic infectious disease is unknown. The brain syndromes. Almost all patients with Lyme overlap between chronic infection, autoimmunity, meningitis have had the rash of Lyme disease, 122 12 A Introduction to Neurological Infections… erythema migrans, prior to the meningitis, but and these patients do not have a high incidence of frequently did not notice it or ignored it after it major irreversible neurological sequelae. A small resolved spontaneously. In European LNB, subset of patients who develop Lyme disease in caused by strains of B . burgdorferi different from Europe develop chronic CNS infl ammation, such those causing American LNB, patients can, in as myelitis, but this has not been seen with any addition to the chronic meningitis discussed regularity in American LNB. Thus, this infection above, also get painful infl ammation of nerve can be chronic, persistent, but is frequently not roots, called Bannwarth’s syndrome. These damaging, even if not immediately identifi ed. patients have radicular pain mimicking at times This is consistent with its proclivity to infect cervical or lumbar disk pain. Cranial nerve collagen-containing structures in the nervous involvement is common in both American and system, rather than attacking neurons or glia. European LNB. In European LNB, almost any cranial nerve can be affected, while in American LNB, unilateral or bilateral facial palsy is almost 2.5 Diagnosis always the cranial nerve involved. The facial palsy usually occurs relatively early in the course Meningitis simply means infl ammation of the of the infection, often early enough not to be meninges, and the diagnosis of any meningitis is associated with a substantial CSF pleocytosis, made by a constellation of symptoms, signs, and and almost never results in permanent signifi cant the demonstration of infl ammation within the defi cit [7 ] . The triad of meningitis, cranial neuri- subarachnoid space as determined by analysis of tis, and radiculoneuritis is not always present in the CSF after lumbar puncture. Once the diagno- LNB, but when it is, it is a distinctive clinical pic- sis of meningitis is made, the causative pathogen/ ture that may allow the infection to be diagnosed process must be identifi ed. The most important on clinical grounds [8 ] . immediate concern is meningitis caused by a T he subacute/chronic meningitis of LNB is pyogenic bacterium such as meningococcus, similar to other subacute/chronic meningitides streptococcus, or staphylococcus, since these caused by other infectious or infl ammatory pro- organisms can cause great damage quickly. Thus, cesses such as tuberculosis, fungal infections gram staining of the CSF and bacterial cultures such as cryptococcus, sarcoidosis, and cancer. are essential in the acute management of the Lyme meningitis and the other causes of sub- meningitis patient. Latex agglutination tests acute/chronic meningitis listed above can cause which rapidly identify antigens of the common either very chronic presentations lasting months bacteria of meningitis, usually S treptococcus or very acute presentations. Most meningitides pneumoniae , Group B streptococcus, E. coli , caused by pyogenic bacteria such as staphylococ- meningococcus ( Neisseria meningitidis ), and cus or streptococcus are acute and patients Hemophilus infl uenzae , have been used as a help- become ill very rapidly; however, some bacteria ful adjunct in diagnosis, although their sensitivity such as L isteria monocytogenes can cause more and specifi city are still uncertain. In Lyme men- chronic presentations. ingitis, these tests are negative, because the spiro- chete which causes the disease is not culturable in routine bacterial media, and no latex aggluti- 2.4 Natural History/Prognosis nation assay is available. For Lyme meningitis, the laboratory diagnosis must be made from the The natural history of Lyme meningitis is not detection of anti-B . burgdorferi antibody in the known, since it is readily treated with antibiotics, serum and CSF and by a history of the skin rash. once identifi ed. The spirochete can be cleared Since high levels of IgG in the CSF can cause a and the symptoms resolved. Lyme meningitis is false-positive CSF antibody result, an index is not fatal. Some patients are not identifi ed until frequently helpful. The demonstration of intrath- many months to years after onset of symptoms, ecal antibody production by measuring CSF and 2 Lyme Meningitis: The Prototypic Meningitis 123 serum anti- Borrelia antibodies is the laboratory or streptococcus have dramatic CSF fi ndings. diagnostic tool of choice in many countries [9 ] . Usually cloudy or in some cases even milky An explanation of CSF/serum testing for intrath- and thick, there are hundreds to thousands of ecal antibody production is provided in Chap. 18 . white cells, mostly polymorphonuclear leuko- Many clinicians will diagnose Lyme meningitis cytes (PMNs), associated with the presence of based on an infl ammatory CSF, negative bacterial bacteria when special stains such as the Gram cultures, and positive antibodies to B orrelia burg- stain are used. The glucose concentration tends dorferi in the blood, although this approach can to be low and the protein high. The “aseptic” result in false-positive diagnoses when other picture is very different: clear to slightly pathogens are responsible in patients from an cloudy fl uid, tens to hundreds of white cells, area endemic for B orrelia burgdorferi infection. mostly lymphocytes or monocytes, with a nor- mal glucose, mildly elevated protein, and absence of bacteria on Gram stain. Some bac- 2.6 Therapy teria, such as B orrelia burgdorferi , Treponema pallidum , or L isteria , are frequently not “pyo- Spirochetes are very sensitive to a variety of anti- genic,” i.e., pus-causing, and thus cause an biotics including penicillin. However, the ability “aseptic” picture. Thus, an “aseptic” pattern of many antibiotics, including penicillin, to kill on CSF analysis does not rule out bacteria as the bacteria requires the bacteria to reproduce, the cause of the infection. and the doubling time of spirochetes in vivo is (c) By pathogenic organism . Pyogenic bacterial, quite long. Therefore, most treatment regimens spirochetal, viral, fungal, other (mycobacte- for LNB require a minimum of 2 weeks of ther- rial, rickettsial, parasitic, etc.). Most clini- apy. Some clinicians insist on extensive courses cians prefer to identify meningitides by their of intravenous antibiotic therapies, despite evi- causative organism, since there are features dence that a 2-week course is effective [1 0 ] . In outside of the CNS that can identify them, fact, studies from Europe demonstrate that oral e.g., facial palsy in Lyme meningitis, pulmo- therapy of LNB with the oral antibiotic doxycy- nary infi ltrate in coccidioidal meningitis. cline is just as effective as intravenous therapy [1 1 ] . Some patients with LNB also have myalgias and arthralgias, which can benefi t from therapy 2.8 Selected Important Infectious with nonsteroidal anti-infl ammatory drugs Meningitides (NSAIDs), in addition to the antibiotics. 2.8.1 Pyogenic (Bacterial) Meningitis The most common causes of acute, non- 2.7 Classifi cation spirochetal bacterial meningitis in adults are Neisseria meningitidis (meningococcus) and (a) By course . Acute vs. subacute/chronic. The Streptococcus pneumoniae (pneumococcus). duration of Lyme meningitis is usually many Almost all patients present with two of the four days to a few weeks, and thus can be classi- following symptoms: headache, fever, neck stiff- fi ed as a subacute to chronic meningitis, ness, and altered mental status [1 2 ] . In patients which contrasts it to acute meningitides such over the age of 50, L isteria monocytogenes is an as viral meningitis/aseptic meningitis or pyo- increasingly common cause of acute meningitis. genic bacterial meningitis which develop Bacterial meningitis is a medical emergency, over hours. which needs to be diagnosed and treated as (b) By CSF profi le . “Bacterial” vs. “aseptic.” quickly as possible by lumbar puncture and intra- Patients with acute bacterial meningitis caused venous antibiotics. Delays in diagnosis and ther- by pyogenic organisms such as pneumococcus apy can be fatal. 124 12 A Introduction to Neurological Infections… T he immune response to bacterial meningitis is

almost completely an innate immune response which is usually inadequate to control the rapid replication of the bacteria. Since the presentation is so acute, the more powerful adaptive immune response does not have enough time to become armed and active. Thus, the spinal fl uid shows large numbers of PMNs, not lymphocytes; bacte- ria also usually can be seen in the CSF by a tech- nique called the Gram stain. Since the infection causes problems with reabsorption of CSF, the CSF is also frequently under increased pressure. Fig. 12.4 Encapsulated budding yeast cells of 2.8.2 Cryptococcal Meningitis Cryptococcus neoformans in cerebrospinal fl uid delin- This form of meningitis is especially important eated by India ink particles because it is one of the more common causes of meningitis in patients with HIV/AIDS [ 13 ] ; it is also diagnosed in immunocompetent individuals. 2.8.3 Syphilitic Meningitis The pathogen of cryptococcal meningitis is Syphilitic meningitis is one of the presentations Cryptococcus neoformans , a fungus which has a of neurosyphilis, which is neurological involve- characteristic gelatinous outer covering. This ment with the spirochete Treponema pallidum characteristic makes it easily detectable in CSF if and resembles Lyme meningitis in many ways. India ink is added since the background becomes Neurosyphilis is discussed later in this chapter black and the fungus with its gelatinous coat under diseases associated with HIV/AIDS. becomes bright from refl ected light (Fig. 12.4 ). It can also be tested for antigenically using the 2.8.4 Tuberculous Meningitis cryptococcal antigen test or directly cultured TB meningitis is one of the most common forms using fungal cultures. of meningitis in the world, since Mycobacterium Its clinical manifestations are similar to those tuberculosis infects one-third of the world’s of Lyme meningitis outlined above, with chronic population, but its incidence in the USA is low. headache, malaise, and fatigue; fever is more For instance, the yearly incidence of new cases commonly present, but may be low grade. Unlike of active TB in the USA is 4/100,000 compared Lyme meningitis, cryptococcal meningitis can to the incidence in Swaziland in Africa of cause raised intracranial pressure, due to 1,200/100,000. TB meningitis is more common decreased reabsorption of CSF and decreased in the pediatric population [1 4 ] and presents level of consciousness. Also, whereas Lyme men- similar to Lyme meningitis with headache, stiff ingitis usually affects only the facial nerve, cryp- neck, cranial nerve involvement, malaise, tococcal meningitis can cause impairment of fatigue; however, in TB meningitis, patients tend almost any cranial nerve. When it occurs in to appear more acutely ill with a higher inci- patients who are HIV-positive, especially if the dence of fever and decreased level of conscious- CD4 count is less than 100/mm 3 , the clinical ness. The presentation of TB meningitis in course may be rapidly downhill; mortality of the children is a bit different than in adults with a infection under these circumstances is high even higher percentage of nausea and vomiting and of with aggressive treatment. Treatment usually prior TB in the former. Very low CSF glucose consists of the antifungal agents amphotericin B (hypoglycorrhachia) is also a characteristic fea- and fl ucytosine. ture of TB meningitis. TB meningitis can also be 3 Herpes Simplex Encephalitis: The Prototypic CNS Parenchymal Infection 125 a lingering chronic meningitis. In 83 cases of chronic meningitis in an immunocompetent 3 Herpes Simplex Encephalitis: population in New Zealand, the most common The Prototypic CNS cause by far was tuberculosis in 60% [1 5 ] . Parenchymal Infection Although TB treatment is generally fairly effec- tive, the combination of an increasing prevalence Growing masses within the parenchyma of the of multidrug resistant bacteria plus the increas- brain, whether they are infections or cancers or ing concurrence of HIV-positivity has led to a other processes, cause symptoms primarily based higher than expected mortality rate for TB on the size and the speed of their growth and their meningitis. location within the CNS. The brain cannot expand beyond the limits of the skull, so space is at a pre- mium. Very large growths can occur with minimal 2.8.5 Aseptic Meningitis symptoms if they grow slowly and are not “irritat- The most common form of acute meningitis in ing,” i.e., do not cause infl ammation or seizures. As the general population is viral meningitis an example frequently seen in practices with large caused by transient adenoviruses or other rela- numbers of immigrants from Mexico and South tively mild viral infections. These are usually America, one parenchymal brain infection, neuro- due to CNS seeding from a systemic viral infec- cysticercosis, frequently results in many cysts tion. They cause headache, malaise, and some- throughout the brain often with no symptoms what- times mild neck stiffness for a few days, and soever. These cysts are sometimes discovered when then resolve without the need for therapy, as the patients complain of muscle aches and cysts are systemic viral infection is cleared by the found in muscle; brain imaging is then obtained immune response. Occasionally, the symptoms and shows multiple brain cysts without neurologi- become severe enough to prompt a visit to the cal symptoms. A similar situation can occur with ER resulting in a lumbar puncture which yields the related parasitic infection, echinococcosis. an “aseptic meningitis” picture and the patient These parasitic infections can be considered as is sent home with NSAIDs and the recom- abscesses since the CNS resident cells are not mendation to maintain hydration and reduce infected. In contrast, infections of the brain resident fever. “Aseptic” which means “absence of sep- cells are called encephalitis, the pathogen is usually sis” is an appropriate name, since the aseptic viral, and the clinical presentation is usually rapid meningitis pattern on the CSF analysis is basi- and dramatic. The most common viral encephalitis cally a compendium of the absence of features in the USA and developed countries is HSE. of bacterial meningitis, as discussed above. That is, there is no predominance of PMNs, there is an absence of raised pressure, and there 3.1 Defi nition are no bacteria. It is not unusual for an occa- sional patient with aseptic meningitis to be mis- HSE is an acute, frequently fatal, encephalitis diagnosed as having bacterial meningitis, since caused by the large DNA virus, herpes simplex the rules for identifying a CSF as “aseptic” are virus (HSV). not inviolable, and clinicians will lean toward being conservative and overdiagnose, rather than underdiagnose, bacterial meningitis. 3.2 Etiopathogenesis/Pathology/ Occasionally, if a lumbar puncture is performed Genetics/Epidemiology in patients with very early bacterial meningitis, an “aseptic” picture can be present, and the The pathogen is a large and complex DNA patient can be inappropriately be diagnosed virus and can be visualized in infected tissue by with viral meningitis. electron microscopy. On the outside of the virus 126 12 A Introduction to Neurological Infections… are glycoprotein spikes, embedded in a lipid among many used by the immune system in a bilayer. Internal to the lipid bilayer is the tegu- sequential, coordinated manner to clear MHV ment, a collection of proteins important for from the CNS [1 6 ] . Similar mechanisms are oper- replication. Internal to this is the nucleocapsid, ative in all encephalitides including HSE. containing double-stranded DNA, as well as The vast majority of patients with HSE are not associated proteins. immunocompromised by standard criteria. Eighty to ninety percent of the population is Because HSE presumably results from a switch of infected with the HSV in an asymptomatic and virus from latency to reactivation, much interest latent form. The virus can reactivate, i.e., begin has centered on a type of RNA called latency- replicating in an infected host, either asymptom- associated transcripts (LATs), which are present in atically or symptomatically. With the latter, the the ganglia of latently affected cells, interfere with symptoms are usually related to a characteristic viral killing, and prolong the survival of infected sore in the lip or skin around the lips. At times neurons. As would be expected, the pathology of when the virus is latent, it exists in the trigeminal HSE is dramatic with a combination of infl amma- ganglion and other ganglia just outside the brain. tion and necrosis, and loss of neurons. There are I nvestigations of HSV infection in experimen- no clear genetic predispositions, although some tal animals has demonstrated that, when activation recent research identifi es mutations in genes con- results in encephalitis, it begins in the trigeminal trolling type 1 interferon responses as predispos- ganglion, rather than coming from blood-borne ing to HSE [1 7 ] . The virus and its encephalitis infection. Once within the brain, the virus lyses appear in nearly all populations. HSE is sporadic neurons rapidly and usually spreads from a tempo- and causes about two cases per million population ral or frontal initial focus. The mechanisms by per year, so, for the vast majority of infected which virus penetrates the CNS, evades the anti- humans, HSV infection is either completely HSV immune response and lyses neurons in the asymptomatic or only a minor occasional irritant brain are poorly understood. It is important to because of transient “cold sores.” remember that HSE is an infection of neurons, as are most viral encephalitides, and thus a gray mat- ter infection. Its clinical presentation is very differ- 3.3 Clinical Manifestations ent from infections of oligodendrocytes and white matter infections, such as PML (see below). In most cases of HSE, the presentation is that of O ne of the best studied acute viral brain infec- an acute focal cerebral lesion, usually localized to tion is that of mouse hepatitis virus (MHV) dis- the frontal lobe or temporal lobe of one side. This cussed briefl y in Chap. 8 . It is generally considered is in distinction to most other viral encephalitides a model of MS because demyelination is promi- (see below) in which involvement of the brain nent, but it is also an excellent model of acute is relatively diffuse, and the clinical syndrome viral encephalitis. Within the fi rst few days of is dominated by progressive confusion and infection, innate immune defenses within the decreased level of consciousness. The time course CNS, such as type 1 interferon s (IFN-a and is hours to a few days. Headache and stiff neck IFN- b ), are critical to control the infection. are common symptoms for this as well as other Beginning after the fi rst few days and extending to meningoencephalitides. Many patients have acute 2 or 3 weeks after infection, virus-specifi c cyto- cognitive diffi culties, personality changes, or toxic CD8-positive T cells are active in preventing confusion and disorientation. Seizures are com- viral replication. To provide long-lasting preven- mon. Fever is almost universal, and its absence tion of viral growth, neutralizing antibody, defi ned raises questions about the accuracy of the diagno- as virus-specifi c antibody which can prevent virus sis. Although imaging reveals a focal lesion, only infection of target cells in vitro, is produced by about a third of patients manifest a clear focal virus-specifi c plasma cells which begin to produce abnormality on examination, with a hemiparesis high levels of antibody after the fi rst few weeks of or other focal fi nding. Patients can worsen quickly infection. These antiviral weapons are chief and HSE can be fatal (see Inset 1 2.4 ). 3 Herpes Simplex Encephalitis: The Prototypic CNS Parenchymal Infection 127 3.4 Natural History and Prognosis Inset 12.4 A 21-Year-Old Woman with Fever and the Worst Headache of Her Life The natural history of the disease has been dra- A 21-year-old college student had the matically altered by the use of antiviral therapy. worse headache of her life associated with Prior to the use of antiviral therapy, the disease fever and came to the emergency room in was fatal in the about 70% of patients, with the the early evening. She was evaluated survivors usually having signifi cant residual neu- initially by the ER staff who noted a tem- rological disability. In two large studies in Sweden perature of 103.5, but her neck was not and the USA in the 1980s, aciclovir outperformed stiff. The patient’s friends, who stayed vidarabine and lowered mortality to 28% in one with her in the ER, said that they thought study and 19% in the other, with more than 50%

she was a bit confused, but she was not of patients returning to normal life [1 8, 19 ] . The disoriented according to the ER physi- prognosis is best in those in whom aciclovir is cian. She did not have a white cell eleva- begun soon after the onset of fi rst symptoms. tion in her blood count, a CT scan of the brain was negative, and the neurology resident who saw her in the late evening 3.5 Diagnosis made the diagnosis of possible aseptic (mild viral) meningitis, did not wish to A high index of suspicion should always be pres- wake the attending on call, so admitted ent for the diagnosis of HSE, since it is the most her for possible further workup on the common sporadic viral encephalitis, is treatable next day. When the attending made rounds with antiviral medication, and the mortality for on the admitted patients early the next untreated HSE is very high. Thus, any individual morning, he found the patient unrespon- with fever and clear neurological symptoms or sive, with irregular respirations, with a signs such as headache or confusion or seizures third nerve palsy on the left (a “blown should be immediately evaluated, and therapy pupil”) caused by pressure of the brain on initiated as soon as possible if there is any clini- the third cranial nerve. Over the night, the cal suspicion of HSE. herpes virus had quickly grown in her Imaging of the brain is ideally performed by brain, killed many brain cells, and the magnetic resonance which usually is clearly abnor- swelling from the cell death and infl am- mal revealing a focal lesion unilaterally in the fron- mation caused pressure on her brain stem, tal or temporal lobe. Often there will be mass effect a syndrome known as raised intracranial showing that the lesion is swollen and compressing pressure (ICP), which, when very severe, other brain structures. Lumbar puncture reveals an causes herniation of the brain, i.e., protru- infl ammatory picture with large numbers of white sion of brain material through a variety of cells sometimes associated with red blood cells. openings at the base of the skull. The The most sensitive and specifi c test for HSE in patient underwent emergency surgery to the acute clinical setting is the detection of HSV decompress her brain and was treated with DNA in the CSF by PCR. Since the turn around aciclovir, but died after a weeklong hospi- time for this assay, i.e., the time from when the talization. The autopsy confi rmed the CSF is obtained to the time the result has returned diagnosis of HSE. from the lab, is usually about 12–48 h, treatment with antiviral medications should not be delayed Author’s note. I rounded with the attending waiting for the diagnosis to be confi rmed. The that morning on my fi rst hour as a neurology PCR of the CSF for HSV is highly sensitive; thus, resident; it was a frightening introduction the absence of CSF PCR positivity is strong evi- to neurology. dence against the diagnosis of HSE. 128 12 A Introduction to Neurological Infections… degrees of host response to the virus although other effects cannot be completely ruled out [ 20 ] . The cells most infected with virus in the brain are those of the macrophage lineage, i.e., perivascular monocytes, macrophages and microglial cells, but astrocyte infection may also be important. HAND is usually classifi ed as a subcortical dementia, in which concentration/ attention, processing speed, executive function, learning and memory are most affected, with language and visuospatial processes less affected. There are no reliable assays or biomarkers, and the disorder is diagnosed by exclusion in an HIV-positive individual when other causes have Fig. 12.5 Gertrude Elion was a researcher at Burroughs been ruled out. In the past, CSF HIV levels had Welcome who received the Nobel Prize in 1988 for the invention or development of many drugs including been a helpful adjunct of diagnosis, but recently, aciclovir, 6-mercaptopurine, azathioprine , allopurinol, with the advent of effective antiretroviral thera- pyrimethamine, and trimethoprim (from the National pies (ART), CSF HIV levels can be undetect- Cancer Institute, h ttp://commons.wikimedia.org/wiki/ able. Another benefi t of effective ART has been File:Nci-vol-8236-300_Gertrude_Elion.jpg ) the rarity of very severe dementia, which had been relatively common in the pretreatment era. Despite the clear benefi t of ART early in infec- 3.6 Therapy tion with HIV, HAND may actually improve when stable patients discontinue ART, a surpris- Aciclovir, also called acycloguanosine, is an ing recent fi nding by HIV researchers, who had effective drug to treat HSV infection, and has actually hypothesized the reverse when they demonstrated effi cacy in HSE. The standard dose began their study [2 1 ] . This fi nding led the is 10 mg/kg every 8 h for 10 days. The drug is authors to conclude that “the balance between phosphorylated to acycloGMP by viral thymidine the neurocognitive cost of untreated HIV vire- kinase, and then to acycloGTP by cellular kinases. mia and the possible toxicities of ART require AcycloGTP is a potent inhibitor of viral DNA consideration.” polymerase, which is the major enzyme respon- The effi cacy of ART also has another negative sible for viral replication. Aciclovir was one of side in patients with opportunistic infections (OIs) many antibacterial and antiviral products invented associated with HIV, i.e., patients who are dually by Gertrude Elion (see Fig. 1 2.5 ). infected with HIV and an associated CNS patho- gen such as cryptococcus, tuberculosis, or JC virus. Patients with OIs who have a combination 3.7 Other Important CNS of a high OI pathogen load and severe immuno- Parenchymal Infections suppression from their HIV may develop active infl ammation in the CNS, if antipathogen immu- 3.7.1 Retroviral Infections of the CNS nity is restored by highly active retroviral therapy; Parenchyma: HIV and TSP this infl ammatory syndrome is called immune Human Immunodefi ciency Virus reconstitution infl ammatory syndrome (IRIS) [2 2 ] . The most common neurological syndrome in IRIS is not a problem unique to the CNS and can patients infected with HIV is HIV-associated be seen in other tissues, such as the eye in cyto- neurocognitive disorder (HAND). The etio- megalovirus retinitis. The therapy of IRIS is diffi - pathogenesis of this disorder appears to be direct cult, but most use anti-infl ammatory medications, viral infection of the brain, associated with varying despite their immunosuppressive properties. The 3 Herpes Simplex Encephalitis: The Prototypic CNS Parenchymal Infection 129 peculiarities of PML-IRIS, which is being increas- sometimes systemic antimicrobials are suffi cient. ingly recognized, will be discussed below. An example of the clinical presentation of a patient with a brain abscess is in Inset 1 2.5 . HTLV1-Associated Myelopathy/Tropical Spastic Paraparesis HTLV1 is a retrovirus which exists as a provirus Inset 12.5 A 38-Year-Old Policeman with associated with T cells, and, unlike HIV, is not Double Vision usually detected in plasma. The infection is found in endemic areas in sub-Saharan Africa, the A 38-year-old policeman over a few days Caribbean, South America, and Japan, where as noticed increasing problems with double many as 1% of individuals are infected with the vision, went to his primary care physician, virus. Of those infected, less than 5% ever develop who referred him to a local neurologist, any spinal cord involvement. HTLV1-associated who recommended immediate evaluation myelopathy/tropical spastic paraparesis (HAM/ in our emergency room. History and exam- TSP) is generally a very slowly progressive myel- ination was positive for a previously healthy opathy with symmetrical weakness in the legs and man without risk factors who had a 4-day less so in the arms. It also causes bladder symp- history of double vision and a 2-day history toms. It is mildly infl ammatory and causes atro- of mild headache. Patient recalled a dental phy over time. The diagnosis is made by exclusion procedure 1 month prior to symptoms, and of other spinal cord diseases in patients who test examination was negative except for a positive for anti-HTLV1 antibodies in the serum, marked right sixth nerve palsy, leading to and can be confi rmed by demonstration of HTLV1 double vision most marked on gaze to the in peripheral blood mononuclear cells. There is no right. Imaging of the brain revealed a large therapy that is generally accepted as successful. oblong mass above the pons which mark- edly enhanced after contrast. The patient 3.7.2 Brain Abscesses was begun on antibiotics, taken to surgery, Whereas viruses cause CNS infections by actively and a walled abscess removed which infecting CNS cells and frequently lysing them, contained turbid fl uid; the fl uid grew in bacterial and parasitic infections, often occur in culture Streptococcus viridans and anaero- the CNS parenchyma as one or more abscesses, bic organisms. After surgery, and a month localized collections of infection which are usu- of antibiotics, the patient progressively ally walled off and cause symptoms by compress- improved and eventually returned to work. ing normal CNS or by causing seizures. The most Author’s note. This patient had a classical common bacterium is streptococcus, but any bac- brain abscess, likely related to seeding of terium can cause a brain abscess. The cause is bacteria into his blood stream during the usually dissemination to the CNS from the blood dental procedure. It is reported that approx- and episodes of bacteremia usually precede symp- imately 10% of brain abscesses are due toms by a few weeks, sometimes from a source of to bacteremia during dental procedures. bacteremia as benign as skin pustule or a tooth However, this occurs so rarely related to cleaning. Parasites, such as T oxoplasma gondii , the number of dental procedures that the Echinococcus , or T aenia solium (causing cysticer- risk of giving antibiotics as prophylaxis cosis), also can cause brain abscesses. Tuberculosis outweighs the risk in the vast majority of can cause abscesses that are sometimes called individuals. However, prophylactic antibi- tuberculomas (Fig. 6.1 ). The diagnosis is some- otics are given to some high-risk individu- times diffi cult, but MRI scanning of the brain usu- als such as those with certain cardiac ally reveals characteristic fi ndings of spheroidal conditions; our patient was a healthy man masses with thick walls in patients with consistent and did not receive prophylactic antibiotics histories and examination. In bacterial abscesses, during his dental procedure. surgical excision is frequently necessary, while 130 12 A Introduction to Neurological Infections… 3.7.3 Progressive Multifocal progressive and fatal. The MRI frequently shows Leukoencephalopathy large confl uent white matter lesions (Fig. 1 2.6 ), PML is caused by uncontrolled infection of the which progressively develop over time usually brain with a polyoma virus called JC virus. over a few months. Since the infection affects oli- Neurological involvement occurs in only a very godendrocytes and white matter tracts, not neu- small percentage of those infected with this virus. rons and gray matter, seizures are not common. The virus is very common as a subclinical infec- PML patients can develop symptoms related to tion in a large percentage, between 55 and 80%, cortical involvement such as aphasias and visual of the general population. PML, an aggressive, fi eld cuts. Patients in whom immunosuppression frequently fatal CNS infection, has only been can be reversed sometimes survive. There is no seen in immunosuppressed patients since immu- effective antiviral therapy for JC virus. nocompetent individuals are able to control the PML-IRIS (see IRIS above) occurs when JC virus. However, precisely what “control” patients with PML undergo a change in therapy means is unclear, since most highly immunosup- to reverse immunosuppression [2 3 ] , and the now pressed, JC virus-positive individuals do not get restored immune response aggressively attacks PML; thus, there are many host factors in the the JC virus in the brain, with associated infl am- control of JC virus which we do not understand. mation and worsening of symptoms and CNS PML was fi rst described by Astrom, Mancall, imaging. The change in therapy that can trigger and Richardson in 1958 when they described PML-IRIS can be either anti-retroviral therapy in three patients, all with lymphoid malignancies, AIDS or removal of immunosuppressive thera- who developed “progressive multifocal” white pies such as the immunosuppressive monoclonal matter lesions (leukoencephalopathy) and died in antibodies. PML-IRIS resembles conceptually a few months after

onset of neurological symp- IRIS seen with other opportunistic infections toms. Any immunosuppressed patient is suscep- such as CMV or cryptococcus in the setting of tible to the disease, and, for many years, the AIDS. PML-IRIS associated with monoclonal leading underlying cause of immunosuppression antibody therapy is still rare enough that clinical leading to PML was AIDS. Now, an increasing experience has not determined whether it behaves number of cases of PML occur in patients receiv- the same or somewhat differently from PML- ing immunosuppressive therapy, including thera- IRIS associated with AIDS. peutic monoclonal antibodies such as natalizumab, rituximab, and efalizumab, targeting the mole- 3.7.4 Other Viral Encephalitides: cules a -4 integrin, CD20, and LFA-1, respec- West Nile and Other Viral tively. a -4 integrin and LFA-1 are primarily Encephalitides adhesion molecules and CD20 is a B-cell anti- West Nile virus gen. Because of PML cases, efalizumab, used for The West Nile virus (WNV) is a mosquito-borne psoriasis, was withdrawn from the market, while RNA virus in the fl avivirus family which causes natalizumab was initially withdrawn, and then encephalitis in humans and horses. Other viruses returned to the market with substantial changes in which cause human encephalitis in this family how it was monitored. PML has also been seen in include St. Louis, Japanese, and Murray Valley patients treated with mycophenolate. encephalitis viruses. It was originally isolated The clinical presentation of PML is different from a human in the West Nile region of Uganda than that of the prototypic CNS parenchymal in 1937 and is part of a large group of encephalitis- infection HSE. Symptoms of PML are clinically causing viruses called arboviruses (a r thropod- more similar to those of acute attacks of MS. bo rne v iruses ), which also include eastern and That is, brain white matter tracts, frequently Western equine encephalitis. Insects other than many of them, are targetted (hence the name mosquitoes can carry arboviruses and transmit “multifocal”), but in PML there are no remissions encephalitis, such as ticks which carry tick-borne as there are in MS, and the disease is generally encephalitis (TBE). TBE causes thousands of 3 Herpes Simplex Encephalitis: The Prototypic CNS Parenchymal Infection 131 Fig. 12.6 Large confl uent white matter lesions of PML later, the left frontal lesion showed a slight size reduction on brain MRI. The fi rst MRI examination (a –d ) revealed with atrophic feature of involved cerebral gyri ( e) . a left frontal homogeneous hyperintense lesion on axial Nevertheless, similar white matter lesions involving also fl uid-attenuated inversion recovery (FLAIR) images (a ) the subcortical “U” fi bers with a “scalloped” appearance corresponding to a hypointense (c ) nonenhancing (d ) developed in the left temporal and parietal lobes ( f ). area on T1-weighted images. Diffusion-weighted imag- White matter lesions progressively became multiple and ing image ( b ) of the same lesion revealed a central core confl uent, affecting asymmetrically both cerebral hemi- of hypointensity surrounded by a rim of high signal spheres as shown in axial FLAIR images obtained 12 intensity suggesting a demyelinating lesion. Nine months months later ( g – h ) cases of encephalitis in Russia and Europe attributes. First, the isotype of immunoglobulin annually. The tick vector of this infection, I xodes normally tested for is IgM since this isotype occurs ricinus , is not found in the USA and is also a vec- at high titers and is persistent for months in this tor of Lyme disease in Europe. Prior to 1999, infection, in contrast to specifi c IgM antibody in WNV was found only outside of the USA and most infections where IgM is a transient phenom- Europe, primarily in Africa and the Middle East. enon of the fi rst few weeks of the infection. Second, In the summer of 1999, an outbreak of WN some patients with WNV infection can develop a encephalitis occurred in New York City. During myelitis characterized by acute fl accid weakness subsequent years, the virus spread across the which has been called a poliomyelitis-like syn- USA, becoming established in mosquito and bird drome because it affects anterior horn cells. populations. The epidemic in the USA in humans The diagnosis of most encephalitides including peaked in 2003 when there were almost 3,000 WNV is made usually by clinical grounds when an reported cases of WNV meningoencephalitis in epidemic of the virus is present. Otherwise, serol- the USA [ 24 ] . Since then the number of cases in ogy can be helpful in WNV infection especially the USA has been in the many hundreds per year. rising IgM anti-WNV antibody levels; PCR or viral The diagnosis of WNV encephalitis is made by culture of the CSF can also be available. Therapy identifi cation of antibodies to WNV in the serum of most viral encephalitides is with supportive and either antibodies or viral nucleic acid in the measures; antivirals have not been tested exten- CSF. This infection is distinctive because of two sively in most non-herpetic viral encephalitides. 132 12 A Introduction to Neurological Infections… 3.8 Rabies, Poliomyelitis, and the Wonder of Vaccination Two parenchymal CNS infections, rabies and poliomyelitis, are debilitating infections which are now rare in the USA because of the effectiveness of the combination of reliable vaccines and strin- gent public health measures. Since 1999, there have been no cases of polio in the USA, while 50 years prior to 1999, in 1949, there were 42,033 reported cases. There are one to two cases of human rabies per year in the USA, compared to 55,000 deaths per year worldwide, mostly in Asia and Africa, according to WHO statistics. For polio, 10 years ago, there was hope that polio could be eradicated, similar to smallpox, after wide use of the oral vaccine had decreased the annual global incidence from 350,000 in 1988 to less than a thousand at the turn of the century. However, since 2000, there has been an increase in the number of polio cases, likely because 17% of the world’s children are not vaccinated. This rep- resents a failure, hopefully temporary, for the WHO, which has targetted polio as one of only two diseases for global eradication; the other is Fig. 12.7 Children after polio, demonstrating the use dracunculiasis, or Guinea worm disease, which of bracing to support weak and atrophied legs (from does not have signifi cant neurological sequelae. Lehava Netivot via the PikiWiki—Israel free image collection project h ttp://commons.wikimedia.org/wiki/ Polio is caused by poliovirus, a picorna virus, File:Piki Wiki_Israel_ ) i.e., small RNA virus, which is found naturally only in humans. Other neurologically important picornaviruses are Theiler’s virus (see Chap. 8 ) neurons are destroyed, there is weakness and and Vilyuisk encephalitis virus [2 5 ] . Despite the wasting of the affected areas and leg bracing is absence of an animal that can naturally be infected required to allow use of the legs for ambulation with poliovirus, research on poliovirus has been (Fig. 12.7 ). Poliomyelitis is an example of a aided by the use of a mutant mouse model which disease which affects the spinal cord, but causes expresses the human receptor for poliovirus (see a predominantly lower motor neuron (LMN) Chap. 8 for more information on mutant mouse presentation [see Chap. 2 for a description of models) and develops poliovirus infection. Other LMN versus upper motor neuron (UMN) inju- picorna viruses causing disease outside of the ries], and in that way mimics amyotrophic lateral nervous system in humans are enteroviruses, sclerosis. There are two types of polio vaccine: Coxsackie virus, and hepatitis A virus, among the oral Sabin vaccine and the injected Salk vac- others. More than 99% of human infections with cine. Each has its advantages and disadvantages. poliovirus are asymptomatic or result in only The critical point is that since the infection is transient symptoms, but in some individuals the only found in humans, the disease can be eradi- poliovirus invades the CNS, and specifi cally tar- cated globally if an adequate percentage of gets motor neurons, usually in the spinal cord. humans are vaccinated. Most individuals with paralytic poliomyelitis The situation is different for rabies. Rabies is survive the initial infection, but because the motor a larger virus, and in a different family, i.e., 4 Infectious Neuritis: Neuropathies of Leprosy and Varicella Zoster Virus 133 and subsequently enters the CNS; some experi- ments in experimental animals have suggested that rabies may enter the CNS after being blood- borne, but this is not accepted as the usual mode of transmission in wild-type rabies. There is a fairly long incubation period from initial infec- tion until entrance into the CNS, usually weeks to months, and during this time the infection can be treated by postexposure prophylaxis (PEP), con- sisting of wound cleansing, administration of rabies immune globulin, and rabies vaccination. However, because the incubation period is not highly predictable and can be shorter than expected, it is recommended that PEP begin as soon as possible after the bite. If PEP is not car- ried out, the virus makes its way to the CNS. The fi rst symptoms of CNS invasion begin with fl u- like symptoms—malaise, headache, and fever— progressing to encephalopathy, agitation, confusion, and fi nally delirium and coma. The disease is untreatable once the infection reaches Fig. 12.8 Rabies virus. This is an electron micrograph of this stage, and the very few individuals who have a cell at high magnifi cation which shows multiple bullet- survived have had severe brain injury. shaped rabies viruses within the cell (from the CDC, http://commons.wikimedia.org/wiki/File:Rabies_Virus_ EM_PHIL_1876.JPG ) 4 Infectious Neuritis: Neuropathies of Leprosy1 and Varicella Zoster Virus Rhabdoviruses (Fig. 12.8 ). The major reservoir of rabies virus is not humans but is animals, These neuropathies bear some resemblances to including skunks, raccoons, bats, foxes, dogs, the prototypic neuroimmunological peripheral and other animals. For each human case of rabies, nervous system disease, Guillain–Barré syn- there are thousands of animals infected with the drome (GBS), discussed in Chap. 9 . They all virus. Thus, vaccination of a human will prevent cause neurological symptoms such as numbness, infection in that human but will not affect the tingling, and weakness, by involving only ner- burden of the virus in the community, or the like- vous system structures outside of the central lihood that others will be infected. For this reason, routine rabies vaccination is only recommended for individuals at higher risk of getting infected, such as animal handlers or those working in ani- 1 Some readers may question why I am including leprosy mal care clinics, shelters, or hospitals; in some in this primer. Most physicians practicing in the USA or Europe will never see a patient with leprosy; the total cases international travelers going to countries number of reported cases in the USA in 2002 was 92. highly endemic for the infection may consider Leprosy is important for at least three reasons. First, it is a rabies vaccination. Rabies in humans occurs after relatively common infection worldwide with millions of the bite of infected animals, or exposure to the individuals disabled because of the infection. Second, it commonly affects the nervous system. Third, leprosy in saliva of infected animals and the presence of an the peripheral nervous system serves as a model of chronic open cut. By mechanisms poorly understood, the infection and the interplay between helpful and harmful virus is thought to travel into peripheral nerves immune responses to the infection. 134 12 A Introduction to Neurological Infections… nervous system. They all result in nerve injury large numbers of organisms, but little infl amma- which causes changes readily detectable on elec- tory response, and the nerve and skin damage tromyography/nerve conduction testing, in con- tends to be less. There may be gene expression trast to CNS diseases which do not affect the signatures in infected tissues that differentiate the readout on EMG/NCV testing. All three result in two ends of this spectrum of disease; genes in the infl ammation within the nerves. However, they leukocyte immunoglobulin-like receptor (LILR) are also very different. GBS affects almost all family were signifi cantly upregulated in lesions nerves to varying degrees, while leprosy and of patients with lepromatous forms of leprosy varicella zoster virus (VZV) are much more lim- relative to other forms of the disease

[2 6 ] . Some ited in affecting only a few nerves. The pace of of the products of these genes are thought to sup- GBS is quite fast, hours to days, while leprosy press innate host defense mechanisms, possibly and VZV are chronic, months to years. And most by blocking antimicrobial activity triggered by importantly, GBS is self-limited because the Toll-like receptors (TLRs). Cell-mediated immu- immune system rights itself over time, while in nity to the bacterium is thought to be the primary leprosy the damage continues as long as the means by which bacteria are killed, and patients pathogen remains in the nerve. with low bacteria loads, paucibacillary leprosy, have high levels of anti-bacterial cell-mediated immunity. The reverse appears to be true for anti- 4.1 Leprosy bacterial antibody levels which are higher in lep- romatous forms with higher bacterial load. 4.1.1 Defi nition Our understanding of the neuropathy of lep- Leprosy is a chronic infection of predominantly rosy has been improved by infecting Schwann skin, upper respiratory tract, and peripheral nerves cells (SCs) in vitro with M. leprae ; this cell is the caused by the pathogen, M ycobacterium leprae . major target cell during active infection. M . lep- M. leprae , the fi rst bacterium to be identifi ed as rae likely infects nerves by entering through their causing disease in humans, by Gerhard Hansen in blood supply and lymphatics; the bacterium binds 1873, is rod-shaped, and closely related to the to and enters SCs. Once inside SCs, the pathogen bacterium causing tuberculosis, M . tuberculosis . survives within the cell, does not induce death of the SC, and does not affect the ability in vitro of 4.1.2 Etiopathogenesis the SC to associate with axons. In the tuberculoid The neuropathy of leprosy is not well understood, form of the disease (see Sect. 4 .1.4 below), in partly because of the lack of good models. The which the number of bacteria is relatively low, bacterium is present in peripheral nerves; the nerve injury occurs more severely and more rap- relative role of the bacterium versus the host idly, implicating strong cellular immune response response to it in nerve injury is not known and as being more important in nerve damage. Nerve may vary from individual to individual. Patients involvement is less dramatic in the lepromatous with leprosy develop both anesthesia, i.e., loss of form, in which the number of organisms is very sensation from nerve damage and pain due to high, but the cellular immune response is weaker. damage to nerves. The pathogenesis of leprosy depends to a large 4.1.3 Pathology extent on the magnitude of the host immune As in the pathology of its cousin, tuberculosis, response vs. the pathogen, with tuberculoid lep- the hallmark of pathology in leprosy is the granu- rosy on one extreme, lepromatous leprosy on the loma. These lesions are composed of giant cells other extreme, and most cases being somewhere consisting of fused, multinucleated macrophages, between. In tuberculoid leprosy, there are few surrounded by epithelioid cells, plasma cells, and organisms but an intense infl ammatory response fi broblasts. The nerve is frequently enlarged and to those few organisms leading to substantial tis- can be readily palpated. Although the usual sue injury. In the lepromatous form, there are involvement is in the peripheral nerve, ganglia 4 Infectious Neuritis: Neuropathies of Leprosy and Varicella Zoster Virus 135 such as the dorsal root, sympathetic and trigemi- forearm, but not the antecubital fossa. Facial and nal ganglia can be involved. The macrophage is trigeminal involvements are frequently seen. the reservoir cell for M. leprae and can contain as Many nerves can become enlarged and palpable. many as 100 M . leprae organisms per cell. The ulnar nerve is most frequently involved and damage to nerves in the arm can lead to hand 4.1.4 Genetics/Epidemiology/ deformities (see Fig. 1 2.9 ). Classifi cation The natural history of the disease is highly Millions of individuals worldwide develop lep- variable and is determined by the type of leprosy. rosy and the number of newly infected people per Tuberculoid leprosy has early damage to nerves year is about a quarter million. The disease is at which may be severe, but often the illness can be least 2,000 years old since M ycobacterium leprae self-limited even without therapy. In contrast, DNA was found in a fi rst century CE tomb in untreated lepromatous leprosy frequently pro- Israel. India has the most cases followed by Brazil gresses to deformity, blindness, and at times and Burma. There has been considerable interest death. in determining genetic risks for leprosy since the organism is present widely in communities but 4.1.6 Diagnosis/Therapy only a small percentage of individuals become Diagnosis is usually is made by the confl uence of chronically infected. It is thought that possibly symptoms and signs. Laboratory confi rmation, genetic factors are responsible for clinical differ- however, is not straightforward. Some centers in ences in patients with leprosy. endemic areas are using an ELISA for a M . leprae antigen called phenolic glycolipid-1 (PGL-1). As 4.1.5 Clinical Manifestations in tuberculosis, multidrug therapy (MDT) is now M ost patients with leprous neuropathy have a used. Rifampicin, dapsone, and clofazimine taken gradual onset of symptoms with either dysesthe- for 1 year are one recommended combination. sias or neuropathic pain. Cooler areas are prefer- Single-dose MDT of rifampicin, ofl oxacine, and entially involved, such as the dorsum of the minocycline can be used a single lesion. Fig. 12.9 “Clawed hand” in lepromatous leprosy. The involved pathologically in leprosy. The involvement of fourth and fi fth fi ngers on the left are “clawed” as a result the ulnar nerve also results in the loss of sensation in these of paralysis of the ulnar nerve the most common trunk fi ngers 136 12 A Introduction to Neurological Infections… 4.2 VZV Infection Infection with the herpes virus, VZV, is a rela- tively common infectious cause of neuropathy in Western civilization [2 7 ] . In many respects, VZV neuropathy also called shingles mimics leprosy, the prototypic infectious neuropathy. In both dis- eases, the pathogen is chronically present in the nerve, infl ammation contributes a great deal to clinical disease, and effective treatments are available. The virus, VZV, has some similarities to that of HSV (see Sects. 3.1 through 3 .6 in this chapter ). Both HSV and VZV have relatively large genomes and are members of the herpes- Fig. 12.10 Herpes zoster (“shingles”). This skin erup- tion is due to reactivation of a latent varicella zoster virus viridae family of double-stranded DNA viruses. (VZV) infection (from Preston Hunt, h ttp://commons. The initial infection is usually acquired during wikimedia.org/wiki/File:Shingles_on_the_chest.jpg ) childhood as chickenpox, and after clearance of the acute infection, VZV becomes latent in neu- rons only. Clinically relevant reactivation occurs mod [2 8 ] (see Chap. 19 ). This patient had been as a skin rash called herpes zoster, or shingles. exposed to a child with chicken pox while she The rash occurs in the forms of vesicles occur- was receiving corticosteroids as a treatment for a ring unilaterally in a dermatomal distribution as relapse of multiple sclerosis, in addition to the shown in Fig. 1 2.10 . Initially, the vesicles are fi ngolimod. This case was unusual and represents clear, but then become turbid and crust within a rare case of acute serious VZV infection in an 5–10 days. Shingles is sometimes preceded by adult. Clinical VZV infection in an adult is almost sensory symptoms such as pain, tingling, or always shingles, reactivation of a decades-old numbness. The pain of the rash can be severe, chronic VZV infection. VZV vaccines are and sometimes pain or sensory symptoms can increasingly being used, both in children and in occur without a rash, which is called zoster sine adults, and are recommended by the CDC. herpete. Symptoms usually resolve after resolu- Shingles is treated in three ways: by using tion of the rash, but sometimes pain can continue antiviral medications such as aciclovir, valaciclo- or even rarely worsen after rash resolution, which vir (Valrex), or famciclovir (Famvir), by treating is known as post-herpetic neuralgia. Headache the pain, and by reversing the immunosuppres- and fever can be a prominent, early manifestation sion which contributed to the infection. When the of shingles. The diagnosis is almost always made patient is taking immunosuppressive medication, by clinical evaluation, but laboratory support can reversing immunosuppression is possible, but be derived from demonstrating high-IgM anti- sometimes, as in the elderly or in terminal HIV/ VZV antibody levels in blood or a positive iden- AIDS this is impossible. Shingles should be tifi cation of the virus in fl uid from the vesicles treated aggressively, because a substantial per- either by PCR or by electron microscopy. centage of patients develop post-herpetic neural- VZV can present in a disseminated, aggres- gia, which can be a debilitating condition sive form in adults who did not have chickenpox requiring large doses of narcotics. as a child. Recently, a death was caused by dis- seminated primary varicella zoster infection in a patient with no history of chicken pox and a neg- 4.3 Immunosuppressed Patients ative baseline varicella zoster antibody titer who was in a clinical trial in MS and received a rela- After initial infection, patients with HIV become tively high dose of a new drug for MS, fi ngoli- progressively more immunosuppressed. This is a 4 Infectious Neuritis: Neuropathies of Leprosy and Varicella Zoster Virus 137 slow, gradual process and serious immunosup- similar to toxoplasmosis. However, PML is seen pression putting the HIV patient at risk for oppor- occasionally in patients immunosuppressed by tunistic infections does not usually occur until medications, such as natalizumab, efalizumab, about 5–10 years after the initial infection. The and rituximab [ 30 ] , while toxoplasmosis has following are neurological infections commonly not been described with those medications. The seen in HIV-infected patients once their CD4+ reasons for this disparity are unknown. PML is cells have dropped below 200/mm 3 : toxoplasmo- described earlier in this chapter in Sect. 3 .7.3 , as sis, PML, cryptococcal meningitis, and neuro- a parenchymal CNS infection contrasting with syphilis. The fi rst two are almost exclusively seen the prototypic CNS parenchymal infection HSE. in immunosuppressed individuals, while the lat- ter two can be seen in immunocompetent indi- 4.3.3 Cryptococcal Meningitis viduals, but are present more commonly in the This infection, which can occur in both immuno- HIV-infected patient. competent and immunosuppressed patients, is described earlier in this chapter as a meningitis 4.3.1 Cerebral Toxoplasmosis resembling the prototypic meningitis of Lyme This infection is only seen in patients with signifi - disease. cant immunosuppression [2 9 ] . At the height of the AIDS epidemic, it was by far the most com- 4.3.4 Neurosyphilis mon CNS manifestation of HIV infection, despite Treponema pallidum is a spirochete which causes the fact that CNS infection with this pathogen is syphilis in humans; transmission is through sex- not seen in immunocompetent individuals and ual intercourse. Much of what we now know that 10% of the population is chronically infected about neurosyphilis is based on inadequate infor- with this parasite. A patient with this infection has mation, i.e., case reports and small series, which been described earlier in this chapter. The patho- suffer from a number of biases [3 1 ] . Our clinical gen is Toxoplasma gondii , a parasite commonly appreciation of this disease is primarily from the present in uncooked food or cat feces. The usual pre-antibiotic and pre-HIV eras, when syphilis fi rst presentation is a seizure in a young person, was more common and occurred exclusively in although focal fi ndings such as hemiparesis or immunocompetent individuals. hemisensory fi ndings can also occur. Diagnosis is Syphilis has a long history, likely dating back to usually made by characteristic imaging, usually Roman times. Descriptions of the disease resur- MRI, which reveals multiple gadolinium-enhanc- faced during the European wars of the late fi fteenth ing brain lesions in an immunosuppressed patient. century when Italian, French, and Spanish soldiers The organism is very sensitive to antibiotics, pri- spread the “red plague” or the “great pox” through- marily sulfadiazine and pyrimethamine; the imag- out Europe, while Spanish and Portuguese sailors ing abnormalities may completely resolve. It is spread the disease to

the Philippines, India, China, one of the few CNS infections for which neurolo- and America. Among other names, it was called the gists will routinely use a therapeutic trial as a rou- German Pox, the Polish Illness, the Portuguese dis- tine diagnostic technique rather than obtaining ease, the Castilian infection, or the French Disease. biopsy evidence of the infection. However, treat- The illness begins with a primary infection ment is not always permanently effective and occurring within days to weeks after sexual con- infection can recur. The prognosis is usually good tact, often manifested as a chancre, a sore on the and mortality is usually from other opportunistic penis. The chancre usually resolves completely infections or progressions of AIDS. and is followed by secondary syphilis which is a skin rash often on the palms, but which can occur 4.3.2 Progressive Multifocal anywhere (see Fig. 12.11 ). Early neurosyphilis Leukoencephalopathy within the fi rst few months of infection can This infection is only seen in patients with sig- involve infection in the CNS without symptoms nifi cant immunosuppression and in that way is or a typical basilar meningitis, similar to Lyme 138 12 A Introduction to Neurological Infections… light, also called Argyll Robertson pupils, can be a feature of this stage. The infl ammation within the brain is minimal, but meningeal infl ammation is present. The most striking symptom in neuro- syphilis, lightning pains, is found in tabes dorsa- lis, another late manifestation of neurosyphilis. These pains are described as bouts of jabbing and lancinating pain usually in the legs. Pains can also occur in the abdomen, leading to a mistaken diagnosis of an acute abdominal surgical emer- gency. The likely localization is the posterior nerve root, and there is loss of pain, position, and vibration senses and occasionally loss of sensory aspects of bladder. Problems with urination and with balance are common. The CSF in tabes dor- salis and GPI are abnormal with a positive CSF VDRL, elevated protein, and frequently increased number of mononuclear cells. The diagnosis of neurosyphilis is made by identifying characteristic antibody responses in Fig. 12.11 Syphilis. Skin involvement is commonly the CSF and serum. Isolation of the causative spi- seen, usually as a relatively early manifestation of the dis- rochete is not routinely attempted because T . pal- ease. The infection is readily cleared at early stages with lidum is a very diffi cult bacteria to culture, since antibiotics it is fastidious and any attempts to culture the pathogen ex vivo have very low yield of positive meningitis, in which there is headache, malaise, results. The most sensitive and specifi c assay for stiff neck, and nonspecifi c symptoms. Over time neurosyphilis is a VDRL of the CSF, an inexpen- persistent infl ammation in the subarachnoid sive fast assay which make use of the fact that space from syphilitic meningitis can involve active infection with T . pallidum induces forma- arteries and meningovascular syphilis can result. tion of an autoantibody to molecules called phos- In this form of syphilis, stroke is common, pholipids. VDRL as an antiphospholipid antibody although the development of focal lesions tends assay and its relationship to the anticardiolipin to be more gradual than in stroke from classical antibody assay and the antiphospholipid antibody atherosclerotic mechanisms. Rarely, neurosyphi- syndrome are discussed at greater length in Chap. lis within the fi rst year can also present with a 18 . A negative FTA/ABS of the serum, an anti- gumma, a mass lesion frequently occurring in the body assay which directly tests binding of anti- posterior fossa, appearing as a contrast-enhanc- bodies to T . pallidum , will effectively rule out ing mass on imaging adjacent to the dura and fre- neurosyphilis, although because of its increased quently with associated edema. cost, many laboratories will only perform an L ate neurosyphilis is not commonly seen now, FTA/ABS assay when the VDRL is positive. relative to the pre-antibiotic era. The classical Although neurosyphilis is not restricted to syndromes, seen commonly in the pre-antibiotic individuals with HIV/AIDS, a large percentage of era, were general paresis of the insane (GPI) or individuals with neurosyphilis have HIV/AIDS, tabes dorsalis. GPI is a dementing process often and in the past few decades neurosyphilis has associated with signifi cant psychiatric manifesta- been increasingly a disease of homosexual men, tions such as mood changes, grandiose delusions, sometimes labeled as men who have sex with men or marked personality changes. The brainstem is (MSM). It is unclear whether HIV/AIDS substan- also involved and irregularly shaped pupils that tially changes the natural history of neurosyphilis. accommodate to near focus, but do not react to Certainly there is no evidence that CNS invasion References 139 occurs more commonly in HIV-positive individu- 15. Anderson NE, Willoughby EW. Chronic meningitis als than those without HIV infection. without predisposing illness – a review of 83 cases. Q J Med. 1987;63(240):283–95. T he treatment of neurosyphilis consists of 16. Savarin C, Bergmann CC. Neuroimmunology of cen- penicillin intravenously or intramuscularly. Some tral nervous system viral infections: the cells, mole- clinicians feel that ceftriaxone IV is superior to cules and mechanisms involved. Curr Opin Pharmacol. penicillin but that remains unproven. 2008;8(4):472–9. 17. Pessach I, Walter J, Notarangelo LD. Recent advances in primary immunodefi ciencies: identifi cation of novel genetic defects and unanticipated phenotypes. References Pediatr Res. 2009;65(5 Pt 2):3R–12. 18. Skoldenberg B, Forsgren M, Alestig K, et al. Acyclovir 1. Pachner AR. Lyme disease. Trends Neurosci. versus vidarabine in herpes simplex encephalitis. 1989;12(5):177–81. Randomised multicentre study in consecutive Swedish 2. Scheld WM, Whitley RJ, Marra CM, editors. patients. Lancet. 1984;2(8405):707–11. Infections of the central nervous system. 3rd ed. 19. Whitley RJ, Alford CA, Hirsch MS, et al. Vidarabine Philadelphia: Lippincott-Williams; 2004. versus acyclovir therapy in herpes simplex encephali- 3. Roos KL, editor. Principles of neurologic infectious tis. N Engl J Med. 1986;314(3):144–9. diseases. New York: McGraw-Hill; 2005. 20. Singer EJ, Valdes-Sueiras M, Commins D, Levine A. 4. Pachner AR, Dail D, Bai Y, et al. Genotype determines Neurologic presentations of AIDS. Neurol Clin. phenotype in experimental Lyme borreliosis. Ann 2010;28(1):253–75. Neurol. 2004;56(3):361–70. 21. Robertson KR, Su Z, Margolis DM, et al. 5. Pachner AR, Basta J, Delaney E, Hulinska D. Neurocognitive effects of treatment interruption in Localization of Borrelia burgdorferi in murine Lyme stable HIV-positive patients in an observational borreliosis by electron microscopy. Am J Trop Med cohort. Neurology. 2010;74(16):1260–6. Hyg. 1995;52(2):128–33. 22. Muller M, Wandel S, Colebunders R, Attia S, Furrer 6. Kaiser R. Intrathecal immune response in patients H, Egger M. Immune reconstitution infl ammatory with neuroborreliosis: specifi city of antibodies for syndrome in patients starting antiretroviral therapy for neuronal proteins. J Neurol. 1995;242(5):319–25. HIV infection: a systematic review and meta-analysis. 7. Clark JR, Carlson RD, Sasaki CT, Pachner AR, Steere Lancet Infect Dis. 2010;10(4):251–61. AC. Facial paralysis in Lyme disease. Laryngoscope. 23. Tan K, Roda R, Ostrow L, McArthur J, Nath A. PML- 1985;95(11):1341–5. IRIS in patients with HIV infection: clinical manifes- 8. Pachner AR, Steere AC. The triad of neurologic mani- tations and treatment with steroids. Neurology. festations of Lyme disease: meningitis, cranial neuritis, 2009;72(17):1458–64. and radiculoneuritis. Neurology. 1985;35(1):47–53. 24. Gyure KA. West Nile Virus Infections. J Neuropathol 9. Hansen K, Lebech AM. The clinical and epidemio- Exp Neurol. 2009;68(10):1053–60. logical profi le of Lyme neuroborreliosis in Denmark 25. Lipton HL. Human Vilyuisk encephalitis. Rev Med 1985-1990. A prospective study of 187 patients with Virol. 2008;18(5):347–52. Borrelia burgdorferi specifi c intrathecal antibody pro- 26. Bleharski JR, Li H, Meinken C, et al. Use of genetic duction. Brain. 1992;115(Pt 2):399–423. profi ling in leprosy to discriminate clinical 10. Steere AC, Pachner AR, Malawista SE. Neurologic forms of the disease. Science. 2003;301(5639): abnormalities of Lyme disease: successful treatment 1527–30. with high-dose intravenous penicillin. Ann Intern 27. Steiner I, Kennedy PG, Pachner AR. The neurotropic Med. 1983;99(6):767–72. herpes viruses: herpes simplex and varicella-zoster. 11. Ljostad U, Skogvoll E, Eikeland R, et al. Oral doxy- Lancet Neurol. 2007;6(11):1015–28. cycline versus intravenous ceftriaxone for European 28. Cohen JA, Barkhof F, Comi G, et al. Oral fi ngolimod Lyme neuroborreliosis: a multicentre, non-inferiority, or intramuscular interferon for relapsing multiple double-blind, randomised trial. Lancet Neurol. 2008; sclerosis. N Engl J Med. 2010;362(5):402–15. 7(8):690–5. 29. Cohen BA. Neurologic manifestations of toxo- 12. van de Beek D, de Gans J, Tunkel AR, Wijdicks EF. plasmosis in AIDS. Semin Neurol. 1999;19(2): Community-acquired bacterial meningitis in adults. 201–11. N Engl J Med. 2006;354(1):44–53. 30. Tan CS, Koralnik IJ. Progressive multifocal leukoen- 13. Jarvis JN, Harrison TS. HIV-associated cryptococcal cephalopathy and other disorders caused by JC virus: meningitis. AIDS. 2007;21(16):2119–29. clinical features and pathogenesis. Lancet Neurol. 14. Be NA, Kim KS, Bishai WR, Jain SK. Pathogenesis 2010;9(4):425–37. of central nervous system tuberculosis. Curr Mol 31. Marra CM. Update on neurosyphilis. Curr Infect Dis Med. 2009;9(2):94–9. Rep. 2009;11(2):127–34. Neurological Manifestations of Systemic Chronic Infl ammatory 13 Disease Both chronic systemic infl ammatory diseases and with this problem, since sarcoidosis is so common. neurological diseases occur frequently so an The life-time risk for sarcoidosis in African- occurrence of both in a single patient may be due Americans, the most commonly involved group, to chance alone. However, there are a number of is as high as 1 in 40 individuals. Neurosarcoidosis systemic infl ammatory diseases which commonly as a mimic of multiple sclerosis has already been involve the nervous system. Selected ones which described in Chap. 6 . are most likely to be seen by a practicing neurol- The most common location within the CNS ogist in the community are briefl y summarized affected by infl ammation and granuloma is the below. A more thorough review of neurological meninges (see discussion on the meninges in involvement in patients with rheumatic disease Chap. 2 ), although the granulomas can occur was recently published by Sofat et al. [1 ] . anywhere in the CNS. Involvement of the cranial Rheumatic disease, or rheumatism, is a term used nerves and chronic meningitis of the base of the to denote the fi eld of medicine of connective brain are common, as is optic nerve involvement tissue and joint disorders, such as rheumatoid (see Fig. 1 3.1 ) and the MRI of the brain may arthritis, systemic lupus erythematosus (SLE), reveal areas of demyelination or gadolinium vasculitides, and other diseases in which infl am- enhancement. Risk/benefi t assessment of treat- mation is prominent and a precise etiology has ment with immunosuppressives must be carefully not been defi ned. performed, since infl ammation and symptoms can resolve spontaneously and “adverse effects associated with high-dose systemic corticoster- 1 Neurosarcoidosis oids, the standard therapy, have discouraged practitioners from initiating treatment in the Sarcoidosis is a relatively common idiopathic absence of signifi cant symptomatic neurologic infl ammatory disease, which can affect many dif- disease” [2 ] . ferent systems of the body. There are many simi- larities of sarcoidosis with tuberculosis, and it seems likely that ultimately a pathogen responsi- 2 Systemic Lupus Erythematosus ble for sarcoidosis will be identifi ed, possibly one similar to Mycobacterium tuberculosis. Usually, SLE, a relatively common autoimmune disease patients have symptoms referable to the involve- affecting multiple organ systems, frequently ment of the lung, eye, liver, or skin. Although involves the nervous system, and neurological isolated CNS involvement without systemic sar- complications have been reviewed extensively by coidosis is unusual among all sarcoidosis patients, both rheumatologists [ 3 ] and neurologists [ 4 ] . In it is not that unusual for a neurologist to be faced the latter review, 128 unselected patients with A.R. Pachner, A Primer of Neuroimmunological Disease, 141 DOI 10.1007/978-1-4614-2188-7_13, © Springer Science+Business Media, LLC 2012 142 13 Neurological Manifestations of Systemic Chronic Infl ammatory Disease Fig. 13.1 Neurosarcoidosis. (a ) Sagittal and (b ) axial cisterns, affecting the cisternal segments of the cranial post-gadolinium T1W images demonstrating thick, irreg- nerves. There are also enhancing nodules along the ular, and nodular leptomeningeal enhancement, which is courses of the cranial nerves more striking along the basilar and perimesencephalic SLE, 94% female, were evaluated neurologically, primary APS. Research criteria for APS have and one or more neuropsychiatric syndromes been developed [5 ] , but many clinicians entertain were present in 102 (80%). The most common the diagnosis when a single test, either anti-cardi- was headache in 57%, moderate to severe cogni- olipin antibody or lupus anticoagulant, is positive tive

impairment in 36%, and sensorimotor poly- in patients with stroke or venous thrombosis. neuropathy in 22% but psychiatric problems were Antiphospholipid antibodies are usually detected also common, especially severe anxiety or depres- either as anti- cardiolipin antibodies in a standard sion. Although many rheumatologists had hoped ELISA (see Chap. 18 for a description of ELISAs) some of the new recombinant monoclonal anti- or in an assay known as lupus anticoagulant (LA). bodies available for targeting specifi c parts of the In the LA test, clotting of the blood in the dilute immune system (see Chap. 19 ) would have effi - Russell’s viper venom time assay (dRVVT) cacy in SLE, recent clinical studies in SLE have (Fig. 13.2 ) is delayed by the presence of a serum been disappointing and there have been no major factor. Other tests which are frequently positive breakthroughs, indicating that neurological man- in APS are the autoantibody assays called the ifestations of SLE will continue to be a major Venereal Disease Research Laboratory (VDRL) problem into the foreseeable future. test or the Rapid Plasma Reagin (RPR) tests com- monly used for screening for syphilis. These tests are positive in syphilis because autoantibodies 3 Antiphospholipid Antibody against phospholipids are generated during active Syndrome syphilis infection. Anti-cardiolipin antibodies that develop during syphilis infection can bind to Some individuals with SLE or other autoimmune cardiolipin independent of the presence of b -2 or infl ammatory processes are found to have glycoprotein, a serum protein. In contrast, anti- autoantibodies to phospholipids in their blood, cardiolipin antibodies that develop in APS require sometimes called secondary antiphospholipid this serum factor for binding. How anti- cardiolipin antibody syndrome (APS) (see Inset 13.1 ). Others antibodies are triggered in APS and whether this develop antiphospholipid antibodies without a process bears any resemblance to anti- cardiolipin clear antecedent or causative process, called development in syphilis are unknown. 4 Sjogren’s Syndrome 143 test result be anticoagulated with either aspirin or moderate doses of warfarin. 4 Sjogren’s Syndrome Sjogren’s syndrome, fi rst described in 1933 by Henrik Sjogren, a Swedish ophthalmologist, is an idiopathic chronic infl ammatory disease, more common in women, characterized by infl amma- tory infi ltrates in salivary and lachrymal glands. These glands normally provide lubricating fl uid to the mouth and eyes, and Sjogren’s syndrome characteristically causes dry mouth and dry eyes. The syndrome can either be secondary, i.e., asso- ciated with other infl ammatory diseases, or pri- mary occurring on its own. The infl ammatory infi ltrates can occur in other tissues such as the Fig. 13.2 Russell’s viper—the snake providing the nervous system, leading to neurological manifes- venom for the dilute Russell’s viper venom time assay. tations in as many as 20–25% of patients with Dilute venom from this viper results in clotting of blood Sjogren’s. Most neurologists and rheumatologists from normal humans in under 30 s, but the time is pro- accept the occurrence of peripheral nervous sys- longed when a lupus anticoagulant is present. (Figure is by Stefan STS, in public domain at h ttp://commons. tem manifestations, primarily peripheral neurop- wikimedia.org/wiki/File:20090613_Daboia_russelii_ athy, as being a frequent manifestation of the Russells_Viper_Kettenviper_Pune.jpg ) disease. This neuropathy is usually a classical stocking-glove axonal sensorimotor polyneurop- APS can be a cause of venous hypercoagula- athy but can be a pure sensory neuropathy or bility and theoretically could predispose to cere- infl ammatory involvement of multiple unpredict- bral venous sinus thrombosis, but whether APS is ably distributed nerves, called mononeuritis mul- linked to neurological disease is controversial. tiplex. Cranial nerves can be involved, usually For many years, it was thought that APS predis- the eighth. Symptomatic muscle involvement can posed to routine thrombotic arterial cerebrovas- also occur. According to two neurologists, one in cular disease, such as atherosclerotic stroke the USA [7 ] and the other in France [8 ] , CNS syndromes, but recent data makes this appear less manifestations of Sjogren’s can also occur, likely. In 1,700 patients included in the although this manifestation of the syndrome is Antiphospholipid Antibodies and Stroke Study more controversial than the peripheral neuropa- (APASS), a prospective cohort study within the thy. CNS manifestations have been reported to Warfarin vs. Aspirin Recurrent Stroke Study consist of myelopathies, encephalopathies, sei- (WARSS), the presence of antiphospholipid anti- zures, or focal involvement of acute onset mim- bodies was not predictive of recurrent thrombotic icking stroke or multiple sclerosis. Oligoclonal events [6 ] . The investigators in the WARSS study bands (OCBs) in the CSF (see Chap. 5 for a felt that routine screening for antiphospholipid description of OCBs) can occur, but are less com- antibodies in patients with ischemic stroke did mon than in MS. Anti-SS-A or anti-SS-B anti- not appear warranted. However, the investigators bodies occur in 50% of patients with Sjogren’s in this study were still concerned enough about CNS presentations, but almost never in patients the presence of these antibodies that they recom- with MS. The diagnosis of Sjogren’s syndrome mended that patients with fi rst ischemic stroke with MS-like disease is important, because it can and a single positive antiphospholipid antibody have a very good response to cyclophosphamide 144 13 Neurological Manifestations of Systemic Chronic Infl ammatory Disease therapy (see Chap. 19 for a description of 10,000 individuals over the age of 50. Symptoms cyclophosphamide). are due to decreased blood fl ow in affected blood vessels, and include headache, scalp tenderness, fever, and pain in the jaw upon chewing. The 5 Vasculitis most common severe neurological complication is decreased visual acuity from decreased blood The term “vasculitis” is used loosely by many fl ow to the optic nerve. Stroke can also be a com- neurologists and other clinicians. The term liter- plication of GCA. PNS involvement in GCA is ally means “blood vessel infl ammation,” and, as uncommon. GCA can overlap with a diffuse such, can be a secondary feature of many dis- muscle aching syndrome in the older population eases. For instance, varicella zoster infection is called polymyalgia rheumatica (PMR) (see Chap. associated with at least two forms of vasculitis: a 11 ). The diagnosis of GCA with or without PMR large vessel unifocal granulomatous arteritis and is made by consistent clinical syndrome associ- small vessel multifocal vasculopathy. Any ated with a highly elevated erythrocyte sedimen- chronic meningitis, such as cryptococcal menin- tation rate (ESR) and anemia. The recommended gitis, can result in infl ammation of blood vessels treatment for GCA is high-dose corticosteroids. which pass in the subarachnoid space. In contrast The etiopathogenesis of vasculitides is to these vasculitides which are secondary to unknown, although, in some forms, there is increas- another disease process, vasculitis affecting the ing evidence that autoantibodies are pathogenic. nervous system can rarely occur as a primary ANCA, anti-neutrophilic cytoplasmic antibodies, vasculitis. divided into perinuclear and cytoplasmic or p- and Primary vasculitis affecting the nervous sys- c-ANCA on the basis of their staining characteris- tem is almost always a nervous system manifesta- tics, are IgG antibodies which bind to myeloper- tion of a systemic vasculitis [ 9 ] . Many systemic oxidase (MPO) and proteinase 3, antigens which vasculitides, which as a group are relatively rare are normally intracellular. However, there is disorders, result in neurological involvement, and evidence that these intracellular proteins can be can be divided into CNS or PNS involvement. induced by cytokines to appear on the surface The pattern of PNS involvement is usually a where they can be targets of circulating autoanti- mononeuritis multiplex. This is because the blood bodies, possibly during infl ammation. Anti-MPO vessels to the nerve, i.e., the vasa nervorum, can antibodies have been demonstrated to be patho- be involved, which causes ischemia of the nerve genic in animal models of vasculitis. This research supplied by that blood vessel. PNS involvement is directly applicable to other infl ammatory can also consist of a distal symmetrical senso- diseases which may be autoantibody- mediated, rimotor polyneuropathy. In contrast, parenchymal especially since it demonstrates that under certain CNS blood vessel involvement tends to be quite conditions the autoantigen target can be a mole- rare among these rare disorders, but when it does cule which under normal conditions is an intracel- occur, the CNS involvement tends to demonstrate lular molecule, but under unusual conditions can a broader spectrum than the PNS involvement. be expressed on the surface, and thus be a target of Diseases within this group include vasculitides autoantibodies. affecting large blood vessels (giant-cell arteritis Very rarely, vasculitis can be a primary phe- and Takayasu’s arteritis), medium-sized blood nomenon only within the nervous system, and vessels (polyarteritis nodosa and Kawasaki’s dis- primary nervous system vasculitis can either ease), and smaller vessels (Wegener’s granuloma- affect the PNS or CNS. Kissl and colleagues tosis and Churg-Strauss syndrome). reviewed 350 biopsy-proven cases of PNS vascu- O f these, giant cell arteritis (GCA) is by far litis and were able to identify 7 (2%) in which the most common, affecting approximately 1 per clinical manifestations were only found in the 5 Vasculitis 145 PNS and no other tissue [ 10 ] . Primary CNS vas- culitis, i.e., affecting the CNS without extra-CNS arm occurring about once every week. manifestations, is even rarer, although for some Over the few months prior to presentation, reason neurologists fi nd the disease fascinating the frequency had increased and she found and frequently make the diagnosis erroneously that she could not study in the library (see Inset 12.3 ). Vasculitis only affecting the CNS because occasionally her movements and no other tissue is called “primary angiitis of would hit someone or something near her the CNS (PACNS)” or sometimes granulomatous and disrupt others. She was initially seen vasculitis of the CNS. In PACNS, there is vessel by a psychiatrist and referred to neurology. wall infl ammation in small and medium vessels The remainder of the history was negative; of the brain parenchyma, spinal cord, and menin- there were no illnesses and no positive ges. The disease usually affects middle-aged oth- family history of movement disorders erwise healthy individuals and is subacute with except for an uncle with Parkinson’s dis- headache, higher cognitive dysfunction, seizure, ease. She was a college tennis player and strokes, and cerebral hemorrhages being in the did not notice any decreased playing abil- spectrum. Two excellent reviews have recently ity over the previous year, although occa- been published by American and French physi- sionally she would lose a point because cians [1 1, 12 ] . Both articles discuss the fact that her involuntary movements would throw PACNS is often confused with other diseases or off her game. syndromes, especially reversible cerebral vaso- Her examination was negative for any constriction syndromes, such as those which abnormalities, but laboratory evaluation occur with subarachnoid hemorrhage or menin- revealed a low red and white blood cell gitides due to chronic infections. Angiography count. An antinuclear antibody assay, a for this disorder has a high false-positive rate, blood test frequently positive in SLE, was and diagnosis should be made by a combination strongly positive as was the VDRL, a blood of clinical criteria, LP and MRI fi ndings. Other test for syphilis. The serum FTA-ABS test more common diseases need to be carefully ruled was negative, indicating that the positive out for two reasons: PACNS is very rare and its VDRL was a biological false positive prognosis is usually poor. The recommended (BFP); see Chap. 18 for an explanation of treatment is with potent immunosuppressives BFP tests. Further evaluation revealed that such as cyclophosphamide. At times, cyclophos- she had SLE with secondary APS. MRI phamide can have a dramatic effect on PACNS imaging of her brain, electroencephalogra- (see Inset 1 3.2 ). phy looking for seizure disorder, and lumbar puncture were normal. The diagno- sis was felt to be a small basal gangliar stroke associated with her secondary APS. Inset 13.1 Uncontrollable Arm Movements in Treatment with daily corticosteroids a 19-Year-Old College Student resulted in a decreased frequency of her RQ was a 19-year-old college sophomore movements, but side effects of the drugs who presented with a complaint of uncon- forced withdrawal of this therapy. trollable movements of her left arm. She Eventually, without therapy, the move- was well until 1 year prior to presentation ments decreased over time to less than once when she had an occasional uncontrolled, a month on

last follow-up 1 year after involuntary tossing movement of her left presentation. 146 13 Neurological Manifestations of Systemic Chronic Infl ammatory Disease Inset 13.2 Headache and Confusion in a with dramatic improvement in both clinical 58-Year-Old-Engineer and MRI manifestations of disease. As of JG was a 58-year-old engineer initially the summer of 2010, the patient had a seen by our University Hospital in February nearly normal mental status examination of 2009. He was well and a highly func- and all MRI lesions had cleared up with the tioning engineer until 11/2007 when he exception of one small area. developed a headache. This progressed in severity, and in early 2008 he was seen by a community neurologist who identifi ed by imaging a right temporal lesion, felt to be consistent with a malignancy. A lumbar References puncture revealed a CSF under normal 1. Sofat N, Malik O, Higgens CS. Neurological involve- pressure, but with a lymphomonocytic plei- ment in patients with rheumatic disease. QJM. 2006; ocytosis, and a negative cytology. In the 99(2):69–79. late spring of 2008, he underwent a resec- 2. Terushkin V, Stern BJ, Judson MA, et al. tion of the lesion. The pathology was read Neurosarcoidosis: presentations and management. Neurologist. 2010;16(1):2–15. as “granulomatous infl ammation; focal 3. Feinglass EJ, Arnett FC, Dorsch CA, Zizic TM, necrosis with perivascular lymphoplasma- Stevens MB. Neuropsychiatric manifestations of sys- cytic infi ltrating features suggestive of temic lupus erythematosus: diagnosis, clinical spec- infl ammatory process.” Work-up for a sys- trum, and relationship to other features of the disease. Medicine (Baltimore). 1976;55(4):323–39. temic process was negative, including CT 4. Brey RL, Holliday SL, Saklad AR, et al. scan of the chest and blood sedimentation Neuropsychiatric syndromes in lupus: prevalence rate were normal. He was treated at fi rst using standardized defi nitions. Neurology. 2002;58(8): with corticosteroids, but in the early winter |1214–20. 5. Kaul M, Erkan D, Sammaritano L, Lockshin MD. of 2008–2009, he had worsening of his Assessment of the 2006 revised antiphospholipid syn- brain MRI with involvement of both tem- drome classifi cation criteria. Ann Rheum Dis. poral lobes and his confusion and memory 2007;66(7):927–30. defi cit were worse. On examination when 6. Levine SR, Brey RL, Tilley BC, et al. Antiphospholipid antibodies and subsequent thrombo-occlusive events I fi rst saw him in February 2009, he was in patients with ischemic stroke. JAMA. 2004; only oriented 1/3, knowing his name only. 291(5):576–84. He did not know where he was, and could 7. Alexander EL, Provost TT, Stevens MB, Alexander not identify the date, month, or year, GE. Neurologic complications of primary Sjogren’s syndrome. Medicine (Baltimore). 1982;61(4):247–57. thinking it was 2014. The president was 8. Delalande S, de Seze J, Fauchais AL, et al. Neurologic “Bush,” but he identifi ed Obama when manifestations in primary Sjogren syndrome: a study prompted with the president’s fi rst name. of 82 patients. Medicine (Baltimore). 2004;83(5): He remembered 0/3 objects at 2 min. The 280–91. 9. Rossi CM, Di Comite G. The clinical spectrum of the rest of the neurological examination out- neurological involvement in vasculitides. J Neurol side of the mental status examination was Sci. 2009;285(1–2):13–21. normal. The MRI of the brain showed a 10. Kissel JT, Slivka AP, Warmolts JR, Mendell JR. The bilateral, extensive temporal lobe process clinical spectrum of necrotizing angiopathy of the peripheral nervous system. Ann Neurol. 1985; with diffuse, but spotty, contrast enhance- 18(2):251–7. ment. The history, examination, biopsy, 11. Birnbaum J, Hellmann DB. Primary angiitis of the and MRI scan were consistent with PACNS. central nervous system. Arch Neurol. 2009;66(6): Cyclophosphamide therapy was instituted 704–9. 12. Neel A, Pagnoux C. Primary angiitis of the central immediately, one infusion every 3 weeks, nervous system. Clin Exp Rheumatol. 2009;27 (1 Suppl 52):S95–107. The Neuroimmunology of Cancer: Paraneoplastic Syndromes 14 and Primary CNS Lymphoma Cancer represents a major, prolonged immuno- affecting the CNS, the abnormal immunoglobulins logical disruption similar to that of infection. are usually not associated with monoclonal anti- This chapter does not address the relatively com- bodies, but detected by specialized tests of poly- mon clinical scenarios of either primary cancers clonal antibody in the serum, referred to as of the brain, which usually are tumors of the glial paraneoplastic antibodies. In most paraneoplastic lineage, or of systemic malignancies that metas- syndromes, autoantibodies are thought to be tasize to the brain, such as lung or breast cancers; related to pathogenesis, but the evidence for a discussion of these processes is beyond the this in most paraneoplastic CNS syndromes is scope of this book. Instead, this chapter primarily incomplete. reviews the much rarer paraneoplastic syndromes, neurological involvement associated with immu- nological alterations caused by a distant tumor. 1.2 Etiopathogenesis This chapter also briefl y summarizes primary CNS lymphoma since this malignancy can mimic It is likely that most paraneoplastic neurological neuroinfl ammatory disease. disorders (PNDs) are immune-mediated. The evi- dence for this is the presence of detectable autoantibodies to CNS tissue in the serum of 1 Paraneoplastic Neurological these patients at levels clearly greater than in nor- Disorders mals or in patients with malignancies who do not have neurological disease. These autoantibodies 1.1 Defi nition can occur in patients without demonstrated malignancies, in which case they are also associ- Most neurological problems associated with ated with neurological disease. In addition, the cancer are caused by metastasis of the cancer to autoantibodies bind to neuronal proteins that fre- the brain or spinal cord, or compression from quently are expressed by the patient’s cancer. cancers pressing on neural tissue, but some are Details of these autoantibodies are given in due to “remote” effects of the cancer on the ner- Sect. 1 .8 of this chapter and in Chap. 18 . These vous system, conditions usually referred to as autoantibodies are not clearly pathogenic in that “paraneoplastic” syndromes. A section of Chap. 9 the evidence that they actually cause the pathol- which discussed tumors producing monoclonal ogy is not strong, but their presence is helpful for immunoglobulins causing injury to peripheral diagnosis. Antibody assays in PNDs are classi- nerves is one example of how a cancer, or a pre- fi ed into two large groups. First, antibodies malignant condition, can “remotely” affect the against cell-surface molecules, such as ion or nervous system. In paraneoplastic syndromes neurotransmitter channels [potassium, calcium, A.R. Pachner, A Primer of Neuroimmunological Disease, 147 DOI 10.1007/978-1-4614-2188-7_14, © Springer Science+Business Media, LLC 2012 148 14 The Neuroimmunology of Cancer: Paraneoplastic Syndromes and Primary CNS Lymphoma or n -methyl-d -aspartic acid (NMDA) receptor], may contribute to pathogenesis. Second, anti bodies to intracellular proteins that do not have access to the target antigen are less likely to be pathogenic. However, as was discussed briefl y in Chap. 13 , in the discussion of anti-myeloperoxidase (MPO) antibodies in vasculitides such as Wegener’s gran- ulomatosis, intracellular antigens potentially can be expressed on the outside of a cell during infl am- mation, so the distinction between these two types of autoantibodies may ultimately for some of the autoantigens and their autoantibodies, if it can be demonstrated that “intracellular” antigens can under certain circumstances be expressed on the cell surface. 1.3 Pathology T he pathology in PNDs is variable. In some cases, there is substantial infl ammation in the areas involved. Most PNDs are likely antibody- mediated but not all; there have been some Fig. 14.1 Loss of cerebellar Purkinje cells in PCD. (a ) instances of cerebellar degeneration with infi ltra- Normal cerebellum showing large Purkinje cells. (b ) tion by T cells in which neurons appear destroyed Cerebellum from a patient with paraneoplastic cerebellar by the T cells in neuronophagic nodules. Neuronal degeneration showing complete loss of Purkinje cells degeneration is a common fi nding as is gliosis, the proliferation of astroglia. elderly in the population, the prevalence of neu- Paraneoplastic cerebellar degeneration (PCD) rological syndromes associated with cancers will is characterized by loss of Purkinje cells, a cere- continue to increase. In addition, as our tools for bellar cell type described in Chap. 2 . These cells detection of these syndromes improve and the can be seen in the normal cerebellum as shown in awareness of these conditions increases, they will Fig. 1 4.1a as very large cells with elliptical cell be increasingly recognized. An estimate of their bodies and 2–3 processes in what is called the prevalence has been 1 in 10,000 patients with Purkinje layer at the interface of the granular cancer, but this may be too low [ 1 ] . There do not layer below and the molecular layer above. In appear to be any genetic predispositions, although Fig. 14.1b in the cerebellum of a patient with PNDs are rare enough and sporadic enough that PCD, Purkinje cells have been lost in the disease no one has carefully evaluated this issue. process, presumably targeted by the anti-Purkinje cell antibodies present in PCD, and there is no Purkinje layer, but the granular and molecular layers are normal. 1.5 Clinical Manifestations These syndromes vary considerably, but the most 1.4 Genetics and Epidemiology distinctive are PCD and limbic encephalitis. Lambert–Eaton myasthenic syndrome (LEMS), As life span increases and the prevalence of can- which was discussed in Chap. 10 , is also a char- cers increases with an increasing number of acteristic PND. 1 Paraneoplastic Neurological Disorders 149 1.5.1 PCD 1.5.2 Limbic Encephalitis The usual fi rst symptom is mild gait unsteadiness The hallmark of limbic encephalitis is a combi- which progresses over time, usually weeks to nation of affective symptoms, emotional lability months, so that by the time the patient comes to or uncharacteristic outbursts, and cognitive prob- the evaluation of a neurologist, obvious severe lems. Mood alterations, hallucinations, short- ataxia (see Chap. 2 ) may be present. Other symp- term memory loss, and sleep problems can toms of involvement of the cerebellum, such as deteriorate to dementia or lethargy. Seizures are problems with eye movement, speech, and swal- not uncommon. An example of a patient with lowing, are common. An example of the history limbic encephalitis associated with anti-NMDA of a patient with PCD is in Inset 1 4.1 . receptor antibodies is presented in Inset 1 4.2 . This syndrome has also been termed “anti-NMDA receptor encephalitis.” Inset 14.1 68-Year-Old-Woman Who Stumbled A 68-year-old previously healthy woman Inset 14.2 The Nursing Student Who Became began to notice some problems with coordi- Confused nation and occasional stumbling. Over the course of a few weeks, this progressively A 27-year-old nursing student presented to became worse and she sought medical atten- the emergency room with a 3-week history tion. She saw her primary care physician who of confusion, aberrant behavior, and could not fi nd any abnormalities and told her s eizure-like movements. She was admitted to return in 1 month if things did not get bet- to the neurology department with a diagno- ter. In 1 month, she was much worse and had sis of status epilepticus (constant seizure had a number of falls. She was referred to a activity) with frontal lobe seizures, neurologist who found a severe cerebellar She was well until about 6–8 weeks ataxia; MRI scan of the brain and lumbar before admission when her schoolwork puncture were normal. During her workup, started deteriorating. Three weeks before she progressed to the point where she was admission she began to act in a strange wheelchair bound. PCD was considered and manner. She had previously been quiet and she underwent evaluation that revealed mul- pleasant, but became agitated, belligerent, tiple enlarged lymph nodes and masses in the and talkative. She became confused and liver, consistent with metastatic cancer. The disoriented, and then developed strange liver was biopsied, and a highly malignant movements of her mouth and face. There cancer was diagnosed pathologically. The was no headache and no fever. One week primary lesion could not be identifi ed. PCD before admission friends and family were was confi rmed by demonstration of anti-Yo fi nally able to get her to the local emer- antibodies in the serum. The patient’s health gency room, where she was admitted to the deteriorated rapidly due to spread of her psychiatric service with a diagnosis of malignancy and she died 4 months after the acute psychotic state versus drug intoxica- onset of her symptoms. The primary of her tion. She did not respond to antipsychotic metastatic cancer

was never identifi ed. medications and in fact worsened, becom- Author’s note . This patient had a character- ing completely disoriented with intermit- istic presentation of PCD in which the tent episodes of severe lethargy. Her facial malignancy presented with paraneoplastic movements worsened and she was trans- neurological disease. Unfortunately, in this ferred to the psychiatric service in our hos- patient, the cancer was highly malignant pital, and neurology was asked to consult. and progressed too rapidly to be treated by Exam revealed a lethargic, but easily the time it was recognized. arousable young woman, disoriented to 150 14 The Neuroimmunology of Cancer: Paraneoplastic Syndromes and Primary CNS Lymphoma person, place, and time. Frequent mouthing The lack of fever and seizures and the movements of her face were present, but no negative herpes simplex virus made viral focal weakness. There were unexplained etiologies less likely. The catatonia and fl uctuations in her pulse rate, blood pres- mouthing movements in the context of the sure, and respiratory rate. The history and other features was suggestive of a parane- exam were consistent with a limbic enceph- oplastic syndrome associated with anti- alitis. During the next few days, she became bodies to NMDA receptors and ovarian unresponsive, but was awake and tracked teratomas [5 ] , which proved on evaluation movement in her room with her eyes. to be the correct diagnosis. These forms of Psychiatrists made a diagnosis of catatonic limbic encephalitis can be responsive to schizophrenia. The diagnosis of limbic removal of the tumor and immunosup- encephalitis was confi rmed by the MRI of pression; however, these did not seem to the brain and spinal tap. MRI of the brain benefi t our patient. showed increased signal in the medial aspect of both temporal lobes, most clearly evident on the fl uid-attenuated inversion recovery (FLAIR) sequences. Lumbar puncture revealed a moderately increased 1.5.3 Dermatomyositis number of white cells, but normal protein Dermatomyositis has been described as a para- and a negative herpes simplex virus PCR. neoplastic syndrome. The clinical presentation of Paraneoplastic antibody panel was sent and this muscle infl ammation is not different from CT scanning of her chest and abdomen that of dermatomyositis without a malignancy were normal. CT scanning of her pelvis described in Chap. 11 . Patients who develop der- only showed a slight enlarged left ovary. matomyositis, especially if they are older, have When the results of paraneoplastic anti- an increased incidence of malignancies when body screen came back with positive test compared with the general population, the most for antibodies to the NMDA receptor, the common malignancies being breast, lung, pan- left ovary was biopsied. A teratoma was creas, and colon. Most studies demonstrate an found and removed. Treatment with corti- association with malignancy in about 15–25% of costeroids and intravenous immunoglobu- cases of dermatomyositis. Factors in dermato- lin produced no clear improvement and she myositis more commonly seen in those with was transferred to a nursing facility. malignancies are older age (greater than 50), Author’s note . This patient had a limbic rapid onset of skin or muscular symptoms, and encephalitis with some distinctive fea- skin necrosis. tures. Although most encephalitides are caused by viral infections, limbic enceph- alitis is commonly caused by a paraneo- 1.5.4 Opsoclonus plastic process. This patient’s initial Opsoclonus is an intermittent involuntary conju- problem was diffi culty with her school- gate eye movements in all directions, frequently work, likely because of the short-term continuous, and usually of low amplitude. Some memory defi cits commonly present. neurologists call this as “dancing eyes.” When Subsequent behavioral changes, with con- it occurs as a PND, it can be associated with fusion and agitation as prominent features, quick involuntary movements of the arms or legs, are typical of limbic involvement. Also which are sometimes called “dancing feet.” When consistent was the autonomic instability. these occur together, they are called opsoclonus- myoclonus or dancing eyes–dancing feet. 1 Paraneoplastic Neurological Disorders 151 Fig. 14.2 The NMDA receptor. NMDA receptors form NR2D. These subtypes produce distinct properties, with a family of receptors that are related in that they are able NR2A and NR2B subunits producing high conductance to bind NMDA and have a heterotetrameric structure. states, while those with NR2C and NR2D are low con- There are four receptor subunits made up of two differ- ductance. Neurotransmitters, such as g -aminobutyric ent types of molecules, NR1 and NR2. Each complete acid (GABA); these are large molecules with multiple receptor molecule contains at least two NR1 subunits binding and modulatory sites. NMDARs respond to a called NR1 and two NR2 subunits; NR2 molecules are host of ligands besides NMDA including glycine, PCP, further subclassifi ed into NR2A, NR2B, NR2C, or and Mg 2+ 1.6 Natural History and Prognosis which antibodies detectable in the serum of these of PND patients react with cell-surface antigens. The most well characterized of these are syndromes The natural history and prognosis are usually of the peripheral nerves or neuromuscular junc- completely related to the underlying malignancy. tion, such as LEMS (described in Chap. 10 ). In Some PNDs can be completely cured by surgical contrast, when the autoantigens are intracellular, removal of the underlying malignancy, such as the pathogenesis is thought to be unknown, or, in limbic encephalitis associated with ovarian tera- some cases, mediated by autoimmune T cells toma and anti-NMDA antibodies (see below). rather than antibodies. Others may linger or progress even after success- A few examples of diseases in which antibod- ful excision or other treatment of the tumor. ies against cell-surface antigens are involved are antibodies to: 1. Voltage-gated calcium channels (VGCCs) in 1.7 Classifi cation LEMS associated with small cell lung cancers. As in many neurological diseases in which etio- 2. Voltage-gated potassium channels (VGKCs) pathogenesis is mysterious, there are multiple in limbic encephalitis. classifi cation schemes for paraneoplastic diseases. 3. NMDA receptors associated with ovarian tera- Two forms of classifi cation are commonly used. tomas in limbic encephalitis (see Fig. 1 4.2 ). The fi rst is by clinical syndrome, e.g., cerebellar Despite the fact that the precise mechanisms degeneration or limbic encephalitis; these are are not well characterized, it appears likely described above under “Clinical manifestations.” that these antibodies contribute to pathogene- The second classifi cation is by presumed sis. More support for this hypothesis has come pathogenesis. from work by Hughes et al. [ 2 ] , who demon- When paraneoplastic diseases are classifi ed strated that in anti-NMDA receptor antibody by presumed pathogenesis, one category is anti- encephalitis, anti-NMDA receptor (NMDAR) body-mediated paraneoplastic syndromes, in antibodies bind to NMDARs in tissue culture 152 14 The Neuroimmunology of Cancer: Paraneoplastic Syndromes and Primary CNS Lymphoma and caused a decrease in NMDAR surface medical problems and symptoms of unexplained density via a mechanism called capping and diffi culty with walking in combination with fi nd- internalization (see Chap. 3 ). This binding ings of ataxia localizable to the cerebellum, para- selectively decreased NMDAR function neoplastic cerebellar ataxia must be considered in vitro without affecting the function of unre- in the differential. lated channels. These effects were also repro- Frequently, paraneoplastic syndromes do not duced by passive transfer of these antibodies cause clear lesions within the nervous system on into Lewis rats. Interestingly, these antibodies imaging. However, MRI scans of the brain in did not affect cell survival or any morphologi- patients with limbic encephalitis can show abnor- cal characteristic of the neurons. malities in the medial portion of the temporal lobe Some paraneoplastic neurological syndromes and patients with cerebellar ataxia may occasion- thought NOT to be due to autoantibodies are ally show some cerebellar atrophy. Many times opsoclonus (or opsoclonus-myoclonus) associated patients with paraneoplastic syndromes have with neuroblastomas usually, and dermatomyosi- abnormal CSFs with elevated protein or number tis associated with a range of malignancies. The of white cells or positive oligoclonal bands. mechanisms for these paraneoplastic syndromes There are distinctive antibody reactivities in are even less well understood than those for the some patients with paraneoplastic syndromes syndromes associated with autoantibodies. which aid in diagnosis when they are present (see Some of the above syndromes that ARE related Sect. on “neuronal antigens in paraneoplastic neu- to autoantibodies may not always be paraneoplas- rological disorders (PNDs)” in Chap. 18 ). These tic. For instance, LEMS patients frequently do not were originally detected using assays of reactivity have associated malignancies. Also, Dr. Angela of patient sera to whole brain slices, but now many Vincent and colleagues at Oxford have stressed of the target antigens have been purifi ed and are that the encephalitides associated with anti-VGKC available in recombinant form to allow faster and antibodies are fi rst, frequently NOT associated more accurate diagnostic assays. with tumors, and second, are highly responsive to immunosuppressive therapies such as plasma exchange and corticosteroids [3 ] . 1.9 Therapy Therapy has two major goals: removing the 1.8 Diagnosis malignancy and decreasing infl ammation. Sometimes removal of the malignancy can be The diagnosis of paraneoplastic syndromes is curative both of the malignant process and the often obvious when patients with known malig- paraneoplastic syndrome. With respect to decreas- nancies present with neurological syndromes. ing infl ammation, many different approaches However, not infrequently, patients without his- have been used, but none has been universally tories of cancer present with the neurological successful. Immunosuppressive and immuno- symptoms prior to identifi cation of the cancer. modulatory agents commonly used in neuroim- In such situations, early diagnosis of a paraneo- munological diseases are summarized in Chap. plastic syndrome can be lifesaving, because 19 ; many of them have been used in paraneoplas- excision of the cancer can be curative. However, tic syndromes. it frequently requires an astute clinician to con- sider the diagnosis since paraneoplastic syn- dromes are rare. 2 CNS Lymphoma The fi rst steps in the diagnosis, as in other neurological diseases, are a complete history and CNS lymphoma is a malignancy of the brain competent physical examination. Thus, in a composed of malignant lymphocytes, usually B middle-aged or elderly individual with no other lymphocytes. Both the clinical and pathological References 153 Fig. 14.3 MRI of the brain in primary central nervous system (CNS) lymphoma showing a large single lesion mostly in the right brain but spreading via the corpus callosum to the left picture can mimic a number of neuroimmuno- lymphoma, the B-cell type; most of the time logical diseases such as MS or infections. The pathology will also show an infi ltrate of nonma- involvement of the CNS can be either secondary lignant T cells. Treatment is usually with high- to a lymphoma elsewhere or can be primary dose methotrexate with or without rituximab, (originating in the CNS). The MRI usually dem- although new treatments are being tested [4 ] . onstrates one or more lesions that enhance with Partial surgical resection has no role and actually gadolinium, although if the lymphoma presents decreases survival. Increasing age is a negative in the context of AIDS, the lesions may not prognostic factor. enhance. Periventricular lesions are not unusual and can mimic MS. However, the gadolinium enhancement is usually diffuse rather than the References patchy enhancement frequently seen in MS. Because lymphomas often respond temporarily 1. Dalmau J, Rosenfeld MR. Paraneoplastic syndromes of to corticosteroid therapy, they are frequently the CNS. Lancet Neurol. 2008;7(4):327–40. confused with other infl ammatory processes. The 2. Hughes EG, Peng X, Gleichman AJ, et al. Cellular and synaptic mechanisms of anti-NMDA receptor encepha- diagnosis of primary CNS lymphoma can litis. J Neurosci. 2010;30(17):5866–75. sometimes be challenging. The cancer, like other 3. Vincent A, Buckley C, Schott JM, et al. Potassium infi ltrative brain tumors, can spread along white channel antibody-associated encephalopathy: a poten- matter tracts. It usually involves the cerebrum tially immunotherapy-responsive form of limbic encephalitis. Brain. 2004;127(Pt 3):701–12. and only rarely the brainstem and spinal cord. 4. Hochberg FH, Baehring JM, Hochberg EP. Primary Multiple lesions are seen at initial presentation CNS lymphoma. Nat Clin Pract Neurol. 2007;3(1): approximately one-third of the time; the appear- 24–35. ance of the tumor can be quite dramatic (see 5. Dalmau J, Gleichman AJ, Hughes EG, et al. Anti- NMDA-receptor encephalitis: case series and analysis Fig. 1 4.3 ). The cell type in primary CNS lymphoma of the effects of antibodies. Lancet Neurol. 2008; is also almost always

malignant non-Hodgkin 7(12):1091–8. Neuroimmunology of Degenerative Diseases and Stroke 15 woman with severe, progressive memory loss, 1 Introduction who died in 1906; Alzheimer obtained her brain and studied its pathology. Using silver stains Degenerative diseases of the nervous system, the developed by Franz Nissl and others, Alzheimer most common of which are Alzheimer’s disease correlated his patients’ clinical condition, which (AD) and Parkinson’s disease (PD), take a huge he called presenile dementia, with its pathological toll on the older population, as does atheroscle- hallmarks. Alzheimer’s disease is a now known to rotic cerebrovascular disease (ASCVD). Any be a common, idiopathic disease of the older pop- potential preventive or therapeutic approach that ulation which results in progressive dementia. might have a positive benefi t/risk ratio should be Dementia is literally “loss of mind,” the loss of pursued to alleviate this burden. There is evi- cognitive function. Ability to learn new informa- dence that these processes have infl ammatory tion is the earliest function lost. Frequently, the components and that down-regulation of key disease is fi rst noted by close relatives since infl ammatory components might ameliorate the patients with AD tend to be apathetic toward their degenerative process. This research is still in the condition. Increasingly, their personalities change developmental stage as of 2011 and there are no and they become more forgetful, confused, and anti-infl ammatory or immunosuppressive medi- less able to care for themselves. The disease is cations now being used as a standard of care for increasingly common with increasing age, and as any of these diseases, but this may change in the many as 1/5 of the population aged 65–74 has future. The immunology of these diseases is a AD. The disease must be distinguished from other large and complex area, so only a very brief out- causes of dementia, such as multiple strokes, also line is presented here. Other chronic neurological a common cause of dementia in the elderly. diseases which may have a immune/infl amma- The pathology is limited to the gray matter of tory contribution, such as narcolepsy and amyo- brain; other organs are not affected. Neurons are trophic lateral sclerosis will not be discussed, lost, and the increasing neuronal loss results in since the available neuroimmunological data is increasing brain atrophy. The pathological hall- even more fragmentary in these diseases. marks on microscopy are senile plaques and neurofi brillary tangles scattered throughout the cerebrum. The senile plaques, also called amyloid 2 Neuroimmunology plaques, are composed of b -amyloid, abbreviated of Alzheimer’s Disease A b , a proteolytic peptide cleaved from a normal membrane protein, amyloid precursor protein AD was fi rst described by Alois Alzheimer (1864– (APP). Neurofi brillary tangles are composed 1915), a German psychiatrist and neuropatholo- of aberrant microtubule-associated proteins, gist. In 1901, he began studying a 51-year-old consisting of an excessively phosphorylated A.R. Pachner, A Primer of Neuroimmunological Disease, 155 DOI 10.1007/978-1-4614-2188-7_15, © Springer Science+Business Media, LLC 2012 156 15 Neuroimmunology of Degenerative Diseases and Stroke normally occurring protein called tau. Many immunized patients, there did not appear to be theories on the pathogenesis of Alzheimer’s dis- signifi cant clinical benefi t with respect to ease exist, ranging from chronic viral infection to improved cognition or survival. Despite these acetylcholine dysfunction, but most theories fi ndings, there is continued research along these revolve around the excessive plaques and neuro- lines with the development of a humanized anti- fi brillary tangles in the disease. A b monoclonal antibody, bapineuzumab, which The immunology of AD has mostly revolved is being tested in mild and moderate AD. around two issues: infl ammatory mechanisms contributing to pathogenesis and the use of vac- cines in treatment. There has been some epide- 3 Neuroimmunology miological evidence that the use of nonsteroidal of Parkinson’s Disease anti-infl ammatory drugs (NSAIDs) provides a protective effect for older individuals from Parkinson’s disease (PD) is nearly as common as developing AD. This is controversial and is not Alzheimer’s disease in the older population. It is accepted by all investigators. However, there was a movement disorder which means that move- adequate interest in this fi nding to result in con- ment is impaired despite normal strength and trolled studies on treatment of various stages of sensation. The most obvious characteristic is AD with NSAIDs none of which showed any tremor, but the symptom most troubling to the effi cacy. Many still believe, however, that patient is bradykinesia, excessively slow move- NSAIDs do indeed have an effect but that the ment because of an inability to effect a smooth drugs need to be used prophylactically prior to rapid movement. Patients say that when their dis- disease onset, not as treatments once AD has ease is active they feel like they are wrapped in a begun. thin plastic sheet; movement is possible but is One arm of the immune response that appears slow and labored. Late in the disease, posture is to be locally activated in plaques is the comple- diffi cult to maintain and cognition can become ment system (see Sect. 2.2.6 of Chap. 1 ). Senile impaired. As in AD, PD may be a problem with plaques in AD contain complement proteins. abnormal or excessive proteins in the CNS, in Complement is found early in amyloid deposi- that there is aggregation and accumulation of the tion, and complement activation is correlated protein a -synuclein. A recent hypothesis which with progression of the disease. AD brains have has attracted great interest is that a -synuclein activated microglia, reactive astrocytes, and stimulates microglial activation which further increased production of proinfl ammatory cytok- injures neurons. Microglial activation is a promi- ines, all of which support the role of the immune nent feature of PD, and these cells express system in the disease. However, increasingly, HLA-DR molecules and CD11b, which is a com- researchers are also considering the possibility ponent of an integrin molecule (for description of that the immune activation may be neuroprotec- HLA-DR and integrins, see Chap. 1 ). tive rather than harmful. Thus, the jury is still out As in the instance of amyloid-b in AD, it has on whether the immune activation seen in not yet been determined defi nitively whether Alzheimer’s disease represents a legitimate tar- a -synuclein accumulation is a cause or an effect get for therapy. of the pathology of the disease. The role of synu- Because of the possibility, the amyloid plaques cleins in normal cellular function is unknown. are toxic to the brain and their clearance might The most dramatic neuropathological fi nding in ameliorate disease, Elan Pharmaceuticals devel- PD is loss of neurons, particularly dopaminergic oped a synthetic Ab referring to it as AN-1792 neurons utilizing the neurotransmitter dopamine and immunized AD patients with this “Alzheimer’s in the substantia nigra, which is located in the vaccine.” The study was prematurely halted midbrain. Lewy bodies (Fig. 1 5.1 ) consist of because of the development of meningoencepha- accumulations of a -synuclein and are character- litis in some of the study participants. Although istic of PD. They are also seen in diseases of the some evidence pointed to less amyloid plaque in “Parkinson-plus complex,” which is Parkinson’s 4 Neuroimmunology of Stroke 157 likely most common, is an atherosclerotic embolus formed by rupture of an atherosclerotic plaque, with fragments released from the plaque fl owing downstream and lodging in a smaller branch artery causing loss of blood fl ow. The second mechanism of stroke occurs at the site of the plaque, when the core of the plaque, the atheroma, erodes through the endothelium, and induces a thrombotic occlusion. There is within an atherosclerotic plaque a core containing lipids and debris from dead cells. Surrounding it is a Fig. 15.1 Lewy bodies in the substantia nigra fi brous cap with smooth muscle cells and colla- (hematoxylin– eosin stain, magnifi cation ×40). The major gen fi bers. Macrophages, T cells, and mast cells pathologic abnormalities in Parkinson’s disease (PD) are neuronal cell loss, gliosis, and loss of pigment in the sub- populate the plaque and are frequently in an acti- stantia nigra, especially in the ventrolateral portion pro- vated state. jecting to the putamen, and the presence of abnormal Increasingly, investigators of atherosclerosis, intracytoplasmic neuronal inclusions called Lewy bodies. in general, and stroke, in particular, consider ath- Lewy bodies consist of an amorphous central core with a halo of radially arranged neurofi laments measuring erosclerosis as an infl ammatory disorder of the 10–20 nm in diameter blood vessel. The initial insult to the blood vessel wall is believed to be the accumulation of lipid- laden macrophages, referred to as foam cells, disease plus a number of other diseases with beneath the endothelial lining. Collections of which Parkinson’s overlaps, such as dementia these foam cells are responsible for slightly raised with Lewy bodies, multiple system atrophy, and fatty streaks. Over time, extracellular lipid rich in progressive supranuclear palsy. cholesterol, T cells, additional macrophages, and Animal models of Parkinson’s disease have smooth muscle cells accumulate. Dendritic cells, provided researchers with opportunities to study immune cells related to macrophages, have also its immunology more systematically. The chemi- been shown to be present. The smooth muscle cal MPTP induces degeneration of the substantia cells produce a collagenous cap over the central nigra degeneration and clinical disease in nonhu- atheromatous core. Hemorrhage into the plaque man primates and can induce neuronal dropout in may also occur and contribute to restricted blood mice, and has been used for many years since its fl ow. A variety of cytokines and adhesion mole- discovery in 1982 by Dr. J.W. Langston [1 ] (see cules (see Sects. 2.2.3 and 2.2.5 in Chap. 1 ) are Inset 1 5.1) . More recently, rotenone, a pesticide, produced by the cells in the plaque and likely has also been shown to induce Parkinson’s dis- contribute to the accumulation of the various ease-like picture in rats. There is some evidence infl ammatory cells within the plaques. At some that cellular immunity can exacerbate the disease point in its evolution, the mature plaque, consist- in these models. In addition, some investigators ing of a lipid-rich center with its live, dying, and have found that some infl ammatory mediators dead cells, becomes unstable and prone to rup- can affect the progression of cell death. ture, releasing embolic fragments or locally active prothrombotic components. Mouse models of atherosclerosis mimic some, 4 Neuroimmunology of Stroke but not all, aspects of human atherosclerosis; the most studied of these is the apo-E knockout. Stroke is the sudden death of CNS tissue by a Knockout of additional genes encoding certain block in blood fl ow, usually as a result of changes infl ammatory molecules reduce atherosclerosis. in cerebral blood vessels caused by atherosclero- Such genes include those encoding chemokines sis. Acute cessation of blood fl ow in an affected and their receptors, adhesion molecules, cytokine artery can be caused in two ways. The fi rst, and signaling molecules, and T cells, so that both 158 15 Neuroimmunology of Degenerative Diseases and Stroke human studies and animal models implicate trexate, immunomodulatory therapies described infl ammation as a key element of atherosclerosis in Chap. 19 . (two very good review articles have been recently published [2 , 3 ] ). Two important diagnostic techniques are based on the concept of atherosclerosis as an Inset 15.1 The Story of MPTP infl ammatory-mediated disease. Positron emis- Illicit laboratories in the 1970s and 1980s sion tomography (PET) scanning of patients attempted to produce congeners of heroin. with atherosclerosis identifi es macrophages in One of the congeners, MPPP, was quite the plaque that take up 18 F-fl uorodeoxyglucose successful in inducing the highs of heroin, (FDG) and have been shown to be prognostic for but a contaminant of the synthesis, MPTP, an occlusive event. A sensitive assay for serum produced a Parkinson’s disease-like syn- C-reactive protein (hs-CRP) is increasingly used drome in four drug abusers as described as an indicator of atherosclerotic infl ammation, by Dr. J.W. Langston [1 ] . MPTP is now and the American Heart Association and US used to induce experimental models of Centers for Disease Control and Prevention have Parkinsonism. defi ned risk groups for atherosclerosis according to their levels of hs-CRP. Whether CRP is sim- ply an indicator of infl ammation or is an infl am- matory stimulus in

atherosclerosis is a subject of References active investigation. Statins widely used to reduce atherosclerotic morbidity and originally 1. Langston JW, Ballard P, Tetrud JW, Irwin I. Chronic introduced to lower serum cholesterol have been Parkinsonism in humans due to a product of meperi- dine-analog synthesis. Science. 1983;219(4587): shown to have the additional therapeutic prop- 979–80. erty of reducing infl ammation. Some clinicians 2. Hansson GK, Libby P. The immune response in athero- also recommend NSAIDs such as aspirin or ibu- sclerosis: a double-edged sword. Nat Rev Immunol. profen to lower atherosclerosis risk. Other inves- 2006;6(7):508–19. 3. McColl BW, Allan SM, Rothwell NJ. Systemic infec- tigators have even suggested the use of more tion, infl ammation and acute ischemic stroke. aggressive measures, such as IVIg or metho- Neuroscience. 2009;158(3):1049–61. Important Rare Neuroimmunological Diseases 16 All of the following syndromes are rare and have annual incidences of less than 1/1,000,000, but 1 Infectious/Postinfectious have importance over and above their frequency in the population. These disorders are sometimes 1.1 Subacute Sclerosing classifi ed as “zebras,” disorders so unusual that Panencephalitis they are normally only considered long down the This is a subacute encephalitis usually seen in list of likely suspects. As noted in sect. 6.3 in children or adolescents caused by infection with Chap. 6 , the term zebra has its origin in the measles virus (Fig. 16.1 ). It is very rare in coun- phrase: “When you hear hoofbeats, think horses, tries in which measles vaccination is the norm, but not zebras,” i.e., when evaluating a patient with has an annual incidence in other countries, such as an unknown diagnosis, a physician should Papua New Guinea and India, as high as 56 per remember that common diseases occur com- million population. Most investigators feel it is monly and that it is more likely to get an unusual caused by a mutated measles virus that is unable to manifestation of a common disease than to have produce multiple measles proteins, but maintains a a common presentation of a zebra. However, all limited persistent infection in the CNS. neuroimmunologists have to think of zebras Initially, SSPE affects the posterior part of occasionally when the diagnostic situation does the brain, spreads to anterior sections and then not bring to mind any “horses.” The conditions affects subcortical areas, brain stem, and spinal described below constitute far from an exhaustive cord. Infl ammation, demyelination, gliosis, list. I encourage neurologists who read this and viral inclusion bodies are hallmarks on chapter to contact me (pachner@umdnj.edu) to pathology. Much of the infl ammation is perivas- describe their most memorable zebra. These syn- cular. Clinically, patients with SSPE develop dromes have been divided into three different cat- subacutely over weeks to months intellectual egories: infectious/postinfectious, autoimmune, deterio ration, decline in school performance, and idiopathic, and provided a short description. and behavioral abnormalities with associated At the end of each disease description is a short movement disorders, seizures, and visual abnor- section on why the disease is important out of malities. Myoclonic jerks, the spasmodic, brief proportion to its incidence. movements of a muscle group are common and A.R. Pachner, A Primer of Neuroimmunological Disease, 159 DOI 10.1007/978-1-4614-2188-7_16, © Springer Science+Business Media, LLC 2012 160 16 Important Rare Neuroimmunological Diseases Fig. 16.1 An electron microscope image of measles virus, the cause of SSPE. This virus, within the paramyxo- Fig. 16.2 George Hoyt Whipple (1878), an American virus family, is quite large for viruses being about 200 nm pathologist, researcher, and medical school administrator in diameter. Another group of viruses within the paramyx- who was known more for his other achievements than for ovirus, distemper viruses, cause a CNS disease in some his description of the disease that bears his name. His mammals but not humans, characterized by infl ammation, research dealt with anemia and the liver; he demonstrated demyelination, and progressive injury resembling multi- in dogs that liver fed to anemic dogs reversed the anemia. ple sclerosis This led to the successful treatment of pernicious anemia in humans by George Minot and William Murphy, who shared the Nobel Prize with Whipple in 1934. He also was are included in diagnostic criteria [1 ] . Diagnosis is a renowned teacher and was the dean of University of made by recognition of the characteristic clinical Rochester’s Medical School for 33 years. In 1907, he picture and confi rmed by brain wave tests (electro- described a disease which he called lipodystrophia intesti- encephalography or EEG), which shows typical nalis, but which has come to be known as Whipple’s dis- ease, which can involve the nervous system (image from periodic high-voltage synchronous diphasic waves, Edward G. Miner Library, University of Rochester as well as by high levels of CSF immunoglobulin Medical Center, by permission of Christopher Hoolihan) levels enriched for anti-measles antibody. Prognosis is poor, because of the absence of an effective ther- environment. The disease usually presents with apy, and most patients die of the disease. A related gastrointestinal symptoms such as abdominal disease, which is even rarer and more deadly than pain, diarrhea, weight loss, malabsorption, and SSPE, is measles inclusion body encephalitis wasting, but it can initially present very rarely as (MIBE), which is seen in immunocompromised a neurological disease [3 ] . Approximately one- individuals and usually causes seizures followed third of patients with Whipple’s disease have by rapidly progressive neurological deterioration. neurological involvement at some point in their disease. Neurologically involved patients fre- Importance . SSPE is an example of how a virus quently have encephalopathies, but a number of infection can cause a chronic infl ammatory demy- presentations in the CNS are possible. Lesions in elinating disease. It is also demonstrates how a the CNS which enhance with gadolinium con- virus can continue to cause progressive injury trast are sometimes seen in the brain, and about despite a strong immune response against the virus., half of neurologically involved patients have a i.e., in SSPE high levels of anti-viral antibody are lymphocytic pleocytosis in the CSF. The organ- present both in the blood and within the brain pro- ism cannot be cultured, so it must be identifi ed duced by plasma cells within the brain [2 ] . with PCR, usually of biopsy tissue or sometimes of CSF, or with immunohistochemistry of affected tissue or of the duodenum. Some patients 1.2 Whipple’s are diagnosed based on periodic acid-Schiff (PAS)-positive inclusion bodies, in the absence Whipple’s disease is the ultimate “zebra” (see of any other cause of their illness, in addition to Fig. 16.2 ). It is caused by the bacterium, a positive therapeutic trial with antibiotics. Tropheryma whipplei , which is widespread in the Treating Whipple’s disease with the antibiotic 1 Infectious/Postinfectious 161 trimethoprim– sulfamethoxazole is usually effec- tive, but other antibiotics may sometimes be required. Importance . Although it is extremely rare, it is important for two reasons. First, it is a treatable cause of chronic CNS infl ammation. Second, it is a classical example of how an infection by an unculturable, but widely present pathogen, can cause chronic infl ammation in the CNS which is diffi cult to diagnose. 1.3 Post-Varicella Zoster Virus Cerebellar Syndrome The sudden onset of problems walking a few days to a few weeks after the onset of chicken- pox, i.e., acute Varicella zoster virus (VZV) infection in children, is the usual presentation of post-VZV cerebellar ataxia. Patients develop varying degrees of cerebellar disease usually manifested by ataxia and tremor, sometimes with Fig. 16.3 Thomas Sydenham (1624–1689) was credited with the fi rst descriptions of scarlet fever, caused by headache and vomiting. MRI of the brain is usu- Streptococcal infection, and post-streptococcal chorea, ally normal, the CSF can show a pleocytosis, and also called Sydenham’s chorea (fi gure in public domain at recovery usually occurs within days to weeks http://commons.wikimedia.org/wiki/Thomas_Sydenham ) even without any treatment. However, frequently intravenous aciclovir is used. It is unclear whether this disease is infectious or postinfectious; sup- chorea of children and presents as involuntary porting the former is the frequent occurrence of choreiform movements sometimes with neurobe- positive VZV DNA in the CSF by PCR. Post- havioral symptoms. Chorea, derived from the viral acute cerebellar ataxia has not been reported Greek word meaning “dance,” is an involuntary with VZV’s cousin virus, herpes simplex virus. movement consisting of rapid motions of the hands and feet. SC is considered a parainfectious Importance . Although this syndrome is uncom- syndrome because it usually presents a few mon among those with chickenpox, i.e., about 1 months after infection with group A b -hemolytic in 4,000 cases of chickenpox, chickenpox is such streptococci. Its natural history is that of subacute a common infection in the pediatric population development to a peak which might last a month that the incidence of this illness is not that low. or two, followed by spontaneous resolution. The However, the syndrome is usually short in dura- diagnosis of SC is clinical because there are no tion with usually relatively rapid recovery even supportive laboratory studies, although some- without therapy. times imaging can reveal infl ammation in the basal ganglia. IVIg and plasmapheresis are felt to speed resolution and support the hypothesis that 1.4 Sydenham’s Chorea this is an antibody-mediated disease, although this has not been defi nitively proven. Sydenham’s chorea (SC), fi rst described by Thomas Sydenham in the seventeenth century Importance . Although rare, SC is important (see Fig. 1 6.3 ) is the most commonly acquired because it is an uncommon adverse effect of a 162 16 Important Rare Neuroimmunological Diseases very common infection, streptococcal infection. (VGKCs) detected by an immunoprecipitation It has been described for years as the classical assay using labeled dendrotoxin can be detected postinfectious autoantibody-mediated CNS dis- in about 40% of NMT patients (see Chap. 17 for ease, and recent work has provided some molec- more information on dendrotoxin). Passive trans- ular support for that pathogenesis [4 ] . fer (see Chap. 8 ) of immunoglobulin G from I t is also important because it is related to a patients with NMT into mice results in increased group of diseases which some clinicians feel packets of ACh released and increased neuronal are inadequately studied, PANDAS (Pediatric activity in dorsal root ganglion cultures [5 ] . Autoimmune Neuropsychiatric Disorders Associated with Streptococci) .This entity has Importance . NMT is important because it is one been described as the underlying disease of a set of an increasing number of neuroimmunological of children who have neuropsychiatric syndromes diseases likely mediated by autoantibodies. Many such as obsessive–compulsive disorder or invol- patients with this disease can now be detected by untary movements following infection with group a new immunoassay made possible by basic A-hemolytic streptococci. The link is felt to be an research into animal toxins, e.g., dendrotoxin autoimmune reaction associated with antibodies (see descriptions of VGKCs and dendrotoxin in to neurons triggered by the strep infection. The Chaps. 17 and 18 ). existence of PANDAS is not well accepted and remains controversial. 2.2 Stiff Person Syndrome 2 Autoimmune Stiff person syndrome (SPS) is a disease caused by excessive muscle contraction of both agonist 2.1 Acquired Neuromyotonia and antagonist muscles, thought to be due to inhibition of presynaptic inhibitory molecules in Clinical features of this non-life-threatening and the spinal cord, possibly related to the inhibitory likely underdiagnosed disease are muscle cramps, neurotransmitter, g -aminobutyric acid (GABA). stiffness, and weakness. Sometimes, myokymia, Most patients develop the disease spontaneously, muscle twitching in the absence of movement of but about 5% of the time it occurs as a paraneo- a joint, is a prominent feature, often in the limbs plastic syndrome. It is thought to be autoanti- or trunk. Electromyography (EMG) is dramati- body-mediated and autoantibodies against a cally abnormal with substantial spontaneous variety of molecules have been identifi ed includ- activity, i.e., muscle electrical activity in the ing glutamic acid decarboxylase (GAD), amph- absence of attempted movement of the muscle. iphysin, and gephyrin. Patients with SPS have The disease is thought to be autoimmune because two groups of symptoms (1) muscle stiffness of its association with other autoimmune disease, and (2) episodic painful muscle spasms. The and because of a positive association with thy- clinical diagnosis can be confi rmed by EMG moma, a benign thymic tumor. NMT can occur in documenting simultaneous contractions of association with symptoms

referable to involve- agonist and antagonist muscles. Treatment has ment of the autonomic nervous system such as been with GABA agonists, sedative drugs, and constipation, excessive salivation and sweating, immunotherapies which have been variably and cardiac arrhythmias as well as encephalo- successful. pathic features such as memory loss or confu- sion; these more complicated forms of NMT are Importance . This syndrome is increasingly being sometimes called Morvan’s syndrome. studied because of its association with antibody Recent work has implicated autoantibodies as reactivity against a variety of antigens, and important in the pathogenesis of NMT. Antibodies because of its occasional occurrence as a para- to human voltage-gated potassium channels neoplastic syndrome. 3 Idiopathic 163 2.3 Swine-Worker’s Neuropathy populations who receive adequate dietary iodine and was fi rst described by Hakaru Hashimoto From 2006 to 2010, Lachance and colleagues iden- (1881–1934). Dr. Hashimoto left Japan in 1907 tifi ed 24 patients with neuropathies who worked in to do research in Germany. He focused on the swine abattoirs in Minnesota and Indiana. These thyroid and found evidence of lymphocytic infi l- patients developed a polyradiculoneuropathy, i.e., tration in the thyroid of some patients with thy- involvement of many nerve roots and peripheral roid disease, what is now called Hashimoto’s nerves, sometimes with symptoms referable to the thyroiditis. It is the most common cause of hypo- brain or spinal cord in addition. This disease is felt thyroidism, affecting up to 0.5% of the popula- to be due to exposure to aerosolized porcine brain. tion mostly women. His publication in 1912 on All of the affected workers had antibodies to mouse the thyroid, in the Archiv Fur Klinishe Chirurgie , brain by immunohistochemistry, and most had IgG the German journal of clinical surgery, was his antibodies to myelin basic protein (MBP) and an fi rst and only publication dealing with the thy- elevated CSF protein. Approximately one-third of roid. The term “Hashimoto’s encephalopathy” workers at the same abattoirs who had no symp- was fi rst used by Lord Brain, a prominent British toms had anti-brain antibodies. The most involved neurologist, who, in 1966, described a patient areas, based on EMG/nerve conduction velocity with neurological involvement with fl uctuating testing, were the most proximal areas of the nerve, thyroid hormone levels. The term has continued the nerve roots, and the most distal. The patients to be used, but is sometimes confused with responded to cessation of exposure and to immu- hypothyroid encephalopathy, in which patients nosuppressive medication. with hypothyroidism from any cause develop neurological symptoms, usually neuropsychiatric Importance . Although rare, this recently described manifestations such as cognitive dysfunction, syndrome demonstrates a number of important affective disorders, and psychosis, sometimes points. First, autoimmunity can be induced in referred to as “myxedema madness.” In contrast, susceptible normal humans by repeated exposure the hallmark of Hashimoto’s encephalopathy, as to molecules immunologically resembling it is usually defi ned, is its responsive to corticos- autoantigens. Second, autoantibodies were teroids, implying that the infl ammation present in detectable in fully one-third of the 85 exposed the thyroid of these patients is also present in asymptomatic individuals but not in normal con- their brains. Thus, the syndrome has also been trols. Third, only a very small percentage of called steroid-responsive encephalopathy associ- exposed individuals became clinically ill. These ated with autoimmune thyroiditis (SREAT) or observations are likely true for many diseases nonvasculitic autoimmune infl ammatory menin- related to the immune system: despite the expo- goencephalitis (NAIM). It usually presents with sure of many individuals to a particular process, encephalopathic symptoms such as behavioral only a fraction of those exposed develop bio- changes, seizures, tremor, or cognitive problems markers consistent with some perturbation, and in a previously healthy individual in the absence only a fraction of those with the biomarkers get of structural disease on imaging of the brain or clinical disease. CSF abnormalities. Hashimoto’s encephalopathy has been recently reviewed [6 ] . One of the authors’ conclusions is that “despite the many 3 Idiopathic advances we have made in the past 130 years, the fundamental questions in thyroid-related enceph- 3.1 Hashimoto’s Encephalopathy alopathies clearly have not changed.” Hashimoto’s disease, an autoimmune disease Importance . Some infl ammatory syndromes are associated with anti-thyroid antibodies, is the unusual and overlap with hormonal diseases, most common cause of hypothyroidism in making them diffi cult to precisely defi ne. 164 16 Important Rare Neuroimmunological Diseases Hashimoto’s encephalopathy is one of those and highly focal severe infl ammation. Imaging syndromes and makes corticosteroid therapy an reveals swelling in one hemisphere with no important potential treatment option in patients involvement of the other. The pathology reveals with undiagnosed encephalopathies. marked infi ltration of the brain with mononuclear cells, predominantly with T-lymphocytes, with- out a clear infectious or autoimmune etiology. 3.2 Behcet’s Syndrome Some have hypothesized that the condition is caused by a viral infection but no virus has been This syndrome, rare in the USA but more com- isolated. Patients are treated with immunosup- mon in Turkey and the eastern Mediterranean pressives but frequently lack of therapeutic area, is primarily a vasculitis. Patients develop response requires hemispherectomy, the surgical recurrent oral ulcerations, and clinical diagnosis excision of one complete hemisphere of the requires at least one of the following other mani- brain. festations: skin lesions, eye lesions, or a positive pathergy test. Pathergy is the development of a papule 1 or 2 days after a needle prick. There are 3.4 Acute Multifocal Placoid no diagnostic laboratory biomarkers. Because Pigment Epitheliopathy Behcet’s does not have female predominance and because no autoantibody has been defi ned, some This is a primarily ophthalmological disease do not feel it is autoimmune in pathogenesis. causing decreased visual acuity frequently fol- However, biopsies of affected tissues consistently lowing an acute infectious disease and is diag- show considerable mononuclear cell infi ltration. nosed based on characteristic creamy-white, Neurological involvement is usually of two dif- multifocal lesions in the retina. Neurological ferent forms, not occurring together in the same involvement in AMPPE is not infrequent and was patient: the more dangerous fi rst and more com- recently reviewed [8 ] . Headache or stroke is mon form is parenchymal involvement usually in common, as well as periventricular white matter the brainstem leading to cranial nerve palsies and lesions on MRI of the brain, and the CSF can be hemiparesis, while cerebral venous sinus throm- consistent with infl ammation. The underlying bosis leading to headache and raised intracranial pathogenesis appears to be vasculitis and severe pressure is the second, less common, form [7 ] . CNS vasculitis can be fatal. Importance . Prevalence rates for Behcet’s syn- Importance . This disorder underscores the impor- drome in Turkey have been quoted as being as tant link between the eye and the brain. Most high as 0.4% of the population. Thus, in that part neuroimmunological diseases can affect the of the world, neuro-Behcet’s must frequently be visual system, but some, such as AMPPE, and its in the differential of CNS infl ammatory events. cousin, Susac’s syndrome (Chap. 6 ), are primar- Behcet’s resembles Hashimoto’s in representing ily ophthalmological diseases which can affect neurological infl ammation in a disease that is the nervous system. usually restricted to other tissues: in Behcet’s the mucous membranes and eyes, and in Hashimoto’s, the thyroid. References 1. Garg RK. Subacute sclerosing panencephalitis. 3.3 Rasmussen’s Encephalitis J Neurol. 2008;255:1861–71. 2. Burgoon MP, Caldas YA, Keays KM, Yu X, Gilden Also known as chronic focal encephalitis (CFE), DH, Owens GP. Recombinant antibodies generated this disease usually presents as a severe acute from both clonal and less abundant plasma cell immu- noglobulin G sequences in subacute sclerosing panen- focal seizure disorder in children. It is important cephalitis brain are directed against measles virus. because of its distinctive, dramatic presentation J Neurovirol. 2006;12(5):398–402. References 165 3. Panegyres PK, Edis R, Beaman M, Fallon M. Primary 6. Schiess N, Pardo CA. Hashimoto’s encephalopathy. Whipple’s disease of the brain: characterization of the Ann N Y Acad Sci. 2008;1142:254–65. clinical syndrome and molecular diagnosis. QJM. 7. Siva A, Saip S. The spectrum of nervous system 2006;99(9):609–23. involvement in Behcet’s syndrome and its differential 4. Kirvan CA, Swedo SE, Heuser JS, Cunningham MW. diagnosis. J Neurol. 2009;256(4):513–29. Mimicry and autoantibody-mediated neuronal cell sig- 8. O’Halloran HS, Berger JR, Lee WB, et al. Acute mul- naling in Sydenham chorea. Nat Med. 2003;9(7): tifocal placoid pigment epitheliopathy and central ner- 914–20. vous system involvement: nine new cases and a review 5. Vincent A. Immunology of disorders of neuromuscular of the literature. Ophthalmology. 2001;108(5): transmission. Acta Neurol Scand Suppl. 2006;183:1–7. 861–8. Neuroimmunological Molecules and Translational Medicine 17 markets, even multiple sclerosis, the most common 1 Moving from Basic Science neuroimmunological disease. That is why most of Discoveries to FDA-Approved the drugs used in neuroimmunological diseases Therapies have been developed for other more common dis- eases, such as rheumatoid arthritis or transplant Basic neuroscience is a rapidly moving fi eld, and rejection, and subsequently tested in neuroimmu- the nervous system is a vast frontier only a small nological diseases after already demonstrated to be fraction of which has been explored. The poten- successful in a more common disease. Ideally, tial for discovery of new molecules and concepts pharmaceutical companies, nonprofi t organiza- in basic neuroscience to be directly applied to the tions, and the government would collaborate to treatment of human neurological disease is high. bring new agents to the bedside; this does happen However, this potential is not fulfi lled as often as to some extent, but in relatively disorganized, ran- possible for a multitude of reasons, some of dom, ineffi cient, and opaque ways. Over the last which were dramatized in the recent popular 5 years, there has been a substantial decline in new movie “Extraordinary Measures” in which a new drug approvals, which, coupled with impending enzyme replacement therapy for Pompe’s dis- loss of patent protection for many profi table medi- ease, a glycogen storage disease with dramatic cations, have resulted in signifi cant cutbacks in CNS complications, went through a number of basic research. These factors may exacerbate the hurdles from bench to bedside. inherent diffi culties in bringing safe, effective med- The enzyme replacement therapy depicted in ications to the clinic. In contrast, the advent of the the movie “Extraordinary Measures” is relatively genetics explosion, biologics, and high-throughput straightforward compared to the highly complex screening methodologies have increased the poten- molecules currently being tested for their effects on tial to develop and test new agents. the immune and nervous systems in neuroimmuno- logical diseases. These agents must be proven to be both safe and effective. Increasingly, new drugs are also being required to be better than currently avail- 2 Biological Molecules able therapies, which means that randomized clini- as Therapies cal trials (RCTs—see Chap. 7 ) need to show that the new agent is signifi cantly better than a current 2.1 Therapeutic Monoclonal therapy, not just better than an inactive placebo. Antibodies Another major hurdle for new drugs is that the drug must be demonstrated to be profi table for the Therapy of human diseases, including neuroim- pharmaceutical company to develop and sell. Most munological diseases, has been transformed by neuroimmunological diseases are relatively small the advent of therapeutic monoclonal antibodies A.R. Pachner, A Primer of Neuroimmunological Disease, 167 DOI 10.1007/978-1-4614-2188-7_17, © Springer Science+Business Media, LLC 2012 168 17 Neuroimmunological Molecules and Translational Medicine (mcAbs) over the past 20 years. The advent of • Some of the mcAbs currently being tested for mcAbs was in the mid-1970s when Georges use in MS were FDA-approved for cancer or Kohler and Cesar Milstein worked together to transplant rejection and are now being tested develop a technique for producing long-term in MS. Some of these, other than rituximab, malignant cell lines producing mcAbs with a are alemtuzumab and daclizumab, which are defi ned specifi city (see Inset 1 7.1 ). The success FDA-approved for B-cell leukemia and for of this methodology was based on Niels Jerne’s kidney transplant rejection. Natalizumab, natural selection theory of antibody formation which targets a -4 integrin, was developed for which postulated that foreign antigens select the both infl ammatory bowel disease and MS, and antibody molecules already present within the is discussed in greater length in Chap. 7 . As body which have the best fi

t. with Rituximab, the mechanism of action of these mcAbs is not well understood, but appears to be through a combination of Inset 17.1 The Scientists Behind Monoclonal Fc-mediated effector functions once the Fab Antibodies has bound to the appropriate target. These include antibody-mediated cellular cyto- C esar Milstein, born, raised, and educated toxicity, complement-dependent cytotoxicity, in Argentina, was a scientist in his late 40s, induction of apoptosis of the target cell, and working at Cambridge University in other effects. England, when in 1975 he published his • The effi cacy and side effects of mcAbs are work on the generation of mcAbs using primarily defi ned by the location, distribu- fused hybridoma cells of predetermined tion, and function of their target. Thus, ritux- specifi cities; the coauthor in that paper was imab and other CD20 mcAbs do not directly Georges Kohler, a postdoctoral student affect T cells, macrophages, or monocytes from Germany in his late 20s. This method- because CD20 is only expressed on B cells. ology was based on the “natural selection” The specifi city of mcAbs is, therefore, exqui- theory of antibody formation formulated by site and fulfi lls what Paul Ehrlich (1854– Neils K. Jerne, a Danish immunologist, 1954), an early twentieth century German when he was a research fellow at the immunologist, dreamed of as a “magic bul- California Institute of Technology. For their let.” Ehrlich, who won the Nobel prize for the work, which paved the way for the mcAbs discovery of Salvarsan therapy of syphilis, as therapies, and for our current under- dreamed of discovering “magic bullets” to standing of antibody generation in vivo, treat infectious diseases. These agents would Milstein, Kohler, and Jerne shared the be molecules that would bind to infectious Nobel Prize for Medicine in 1984. agents with high specifi city and toxins could be attached on another end of the molecule to kill the pathogen. Current therapy with mcAbs The fi rst mcAb approved by the FDA was fulfi lls some of Ehrlich’s hopes about “magic rituximab in 1997, for B-cell non-Hodgkin lym- bullets.” phoma resistant to other chemotherapies. It is • McAbs potentially avoid idiosyncratic organ now being used for other lymphomas in addition. injuries of chemicals which may only be found Rituximab targets CD20, a molecule on the sur- either in phase 3 clinical trials or after wide- face of B cells. Interestingly, the precise mecha- spread use. However, targeting a specifi c mol- nisms by which Rituximab is effective in ecule with mcAbs may not be completely safe, lymphoma therapy are not known, although many because of the important role some of these possible mechanisms are postulated. Rituximab molecules may play in normal functions. For and other therapies targeting B cells are discussed example, a small percentage of patients who at greater length in Sect. 2 .2.1 as an important receive natalizumab therapy develop progres- neuroimmunological molecule. sive multifocal leukoencephalopathy (PML) 2 Biological Molecules as Therapies 169 (see Chap. 7 ), an unanticipated and frequently (TNF) receptors to bind to soluble TNF-a , a deadly consequence of targeting an adhesion pro-infl ammatory cytokine. Etanercept blocks molecule. TNF-a action by binding to TNF in the serum • Given the “magic bullet” appeal of mcAbs, and preventing its binding to TNF receptors in and their effi cacy in treating a number of dis- the body. It is a fusion molecule consisting of the eases, it is likely that more and more mcAbs Fc portion of human IgG1 and the p75 portion of will be developed in the next decades for the the TNF-a receptor. No decoy receptor biologic treatment of neuroimmunological diseases. is yet available for patients with neuroimmuno- Some of these may be developed specifi cally logical disease. for MS, the most prevalent neuroimmunologi- cal disease, but it is likely that most will con- tinue to be tested in neuroimmunological 2.2 Molecules as Targets of Therapy diseases only after having been shown to be or of Disease: CD20, Aquaporin-4 effective in cancer, autoimmune problems, or Receptor, TNF-a , Sphingosine-1- other diseases. It is also likely that unforeseen Phosphate Receptors, CD52, side effects will continue to occur, since our MOG, Channels knowledge of the function and distribution of potential targets will frequently lag behind the 2.2.1 CD20 eagerness to use these “magic bullets” in our (a) The molecule . CD20 is a protein of unknown war against disease. function present on the surface of nearly all B cells, with the exception of very early B cells 2.1.1 Biologics and fully differentiated plasma cells. It does mcAbs represent a member of a class of relatively not appear to be present on other cell types. new therapies called biologics. These are materi- (b) The target . The fi rst mcAb to be FDA- als isolated from natural sources and are usually approved, rituximab, targeted CD20 for the produced by biotechnologies such as molecular treatment of lymphoma; this therapy has or cellular biological techniques, usually using undergone some testing in patients with MS, recombinant DNA methodology. Thus, they are but further studies on anti-CD20 therapies in differentiated from chemicals, which historically MS will likely use molecules other than have been the major source of therapeutic drugs. rituximab. One reason for the need for other Usually, biologics are regulated differently from forms of anti-CD20 was that some MS chemicals, because of major differences in how patients developed anti-rituximab antibod- they are produced and in their quality control. ies. Thus, other more “humanized” anti- T he biologics currently most frequently used CD20 mcAbs, such as ocrelizumab and in neuroimmunological diseases are the inter- ofatumumab, are currently being tested in feron- b compounds in MS. These are produced MS clinical trials. either by bacteria (IFN-b -1b) or by Chinese ham- ster ovary cells (IFN-b -1a) and are discussed in more detail in Chap. 7 . Another form of biologic 2.2.2 Aquaporin-4 widely used in neuroimmunological disease is 1. The molecule . The aquaporins are a group of intravenous immunoglobulin (IVIg), which is membrane molecules whose functions include discussed in Chap. 19 in greater length. regulation of the fl ow of water through cells. Another example of a type of biologic treat- Aquaporin is a complex molecule (Fig. 1 7.1 ) ment that can be used to specifi cally target a par- with a number of transmembrane loops and ticular molecule is a recombinant decoy receptor, intracellular and extracellular domains. There an example of which is etanercept. This drug, are at least four different aquaporin molecules. approved for use by the FDA for psoriasis and Aquaporins were fi rst described by Peter Agre various forms of arthritis, utilizes the known (see Inset 1 7.2 ). Aquaporin-4 in the CNS is structure of one of the tumor necrosis factor localized to astrocytic end-feet (Fig. 18.1 ). 170 17 Neuroimmunological Molecules and Translational Medicine appear to be pathogenic in animal models of the disease, but the link between these autoan- tibodies and the clinical phenotype of the dis- ease remains obscure. NMO is a mimic of multiple sclerosis (see Chap. 6 ), and anti-aqua- porin-4 antibodies are generally not present in MS. Since NMO is treated differently than is MS, the identifi cation of aquaporin-4 as a target of autoantibodies has spurred the development and use of a test for these antibodies (see Chap. 18 ) in patients with consistent clinical pictures of CNS infl ammation and demyelina- tion, which has aided in the use of appropriate treatment for NMO. Fig. 17.1 Hypothetical structure of the aquaporin water channels. The water channels consist of six transmem- 2.2.3 Tumor Necrosis-a brane-spanning regions (c ylinders ), which surround two 1. The molecule . TNF-a is about 17 kDa in size loops of the protein (E and B) that form a pore of just the and usually is studied as a soluble cytokine. It right size in the membrane to allow passage of water mol- ecules. Because this is a passive transport process, water is produced predominantly by macrophages can fl ow in either direction across the membrane, depend- during infl ammatory reactions and binds to ing on concentration gradients (out = extracellular, well-characterized TNF receptors which are in = intracellular). Other neutrally charged molecules of a present on most cells. A local increase in TNF similar diameter (e.g., urea) also can pass through this channel. This hypothetical structure recently has been will result in the clinical hallmarks of infl am- confi rmed by X-ray crystallography studies mation. It is structurally related to TNF-b , another cytokine, also called lymphotoxin. 2. The target . The highly infl ammatory nature of Inset 17.2 TNF-a has made it into one of the most popu- Peter Agre and Aquaporin lar targets for anti-infl ammatory therapies. The Dr. Agre’s discovery of aquaporin was seren- mcAbs infl iximab, certolizumab, and adali- dipitous. In 1988 while attempting to purify mumab, as well as the fusion protein, etaner- the 30 kDa Rh, a protein on the surface of red cept, specifi cally target TNF-a . These biologics blood cells, his laboratory was faced with a are used in a variety of infl ammatory diseases, troublesome 28 kDa “contaminant,” initially but the most prevalent use is in rheumatoid thought to be a fragment of the Rh protein. arthritis, a relatively common idiopathic con- His work ultimately shifted from work on dition, affecting 1% of the population, causing the Rh protein to work on the 28 kDa protein pain, swelling, and deformity in the joints. which proved to be a water channel protein, Early in the development of anti-TNF-a bio- which he called “aquaporin.” logics, MS seemed an obvious disease to which to apply these therapies. Investigators found that TNF-a blockade in the animal model of MS, 2. The target . One of the most notable advances experimental autoimmune encephalomyelitis in the last decade in neuroimmunological dis- (EAE) (see Chap. 8 ) resulted in marked improve- ease has been the fi nding that the serum of a ment in disease, providing further apparent ratio- large percentage of patients with Devic’s dis- nale for its use. CSF levels of TNF-a correlated ease, also called neuromyelitis optica (NMO), with disease progression. However, a number of contains autoantibodies which target aqua- studies, including a relatively large phase II study, porin-4 in the CNS. These autoantibodies demonstrated that not only was TNF blockade 2 Biological Molecules as Therapies 171 not helpful, but also it could potentially worsen Interestingly, CD52 is not present on mouse MS relative to untreated controls [1 ] . The mecha- lymphocytes, so functional experiments are nisms by which TNF blockade ameliorates hard to design, and the functional role of CD52 infl ammation in rheumatoid arthritis, but exacer- is unknown. bates it in MS, are unclear. There are two impor- 2. The target . Alemtuzumab is FDA-approved tant take-home messages: fi rst, that infl ammation for use as second-line therapy for chronic in the CNS is not necessarily responsive to the lymphocytic leukemia. Because CD52 is pres- same manipulations as infl ammation outside of ent on such a large percentage of cells, alem- the CNS, and second, that results in the EAE tuzumab results in marked immunosuppression model of MS are frequently not predictive of and signifi cant adverse effects. In the recent results in the human disease. phase II study of alemtuzumab in MS, there was one fatal case of immune thrombocy- 2.2.4 Sphingosine-1 Phosphate topenic purpura (ITP), a high incidence of Receptor autoimmune thyroiditis, and a higher inci- 1. The molecule . Sphingosine-1 phosphate (S1P) dence of infections [2 ] . receptors represent a family of receptors that bind S1P and are part of a broader family called 2.2.6 MOG high-affi nity G protein-coupled receptors 1. The molecule . Myelin oligodendrocyte glyco- (GPCR). S1P is made from intracellular sphin- protein (MOG) is an approximately 25 kDa gosine during normal cell maintenance of the sized protein which has attracted a great deal sphingomyelin present in the cell membrane. of attention as a potential autoantigen in MS. Levels of this molecule are high in plasma but It has been utilized extensively as an encepha- low intracellularly; S1P levels also increase litogen, i.e., inducer of CNS injury when intracellularly in sites of infl ammation. injected into experimental animals in EAE as 2. The target . Because of the above

facts, S1P described in Chap. 7 . It is exciting for at least receptors were felt to be potential targets for three reasons. First, it is found exclusively in immunosuppression. The drug fi ngolimod CNS myelin. Second, it is one of the only pro- (see Chap. 7 ), structurally related to S1P, was teins of myelin that is expressed extracellu- found to be an S1P functional antagonist, larly, on the outermost lamella of the myelin working by down-modulation of lymphocytic sheet, and thus would be a logical target of S1P to slow S1P-dependent egress of lympho- autoantibodies and cellular immunity. Third, cytes, especially T cells, out of lymph nodes, the full-length protein as well as certain pep- and thus resulting in substantial lymphopenia tides of the protein are highly active in multi- in the peripheral blood. It was tested for its ple different animal models of EAE. effect on organ transplantation, but was not 2. The target . In most models of EAE induced by more effective than currently available ther- MOG, anti-MOG antibody production is nec- apy. However, recent studies in MS showed essary to induce full-blown disease including substantial effi cacy with reasonable safety, infl ammation, demyelination, and substantial and the drug has been FDA-approved for use disability. Some data supports the hypothesis in MS (see Chap. 19 ). that early in MOG-induced EAE, T cells with specifi city for MOG result in infl ammation 2.2.5 CD52 within the CNS making the blood–brain bar- 1. The molecule . CD52 is a protein present in rier more porous and that later anti-MOG anti- large amounts on the surface of mature lym- bodies diffuse through the impaired phocytes, monocytes, and dendritic cells but blood–brain barrier and result in antibody- not on their stem cells. Thus, CD52 treatment mediated injury demyelination and injury. with the drug alemtuzumab depletes these This two step hypothesis is supported by the cells but the depletion is not permanent. fi nding that monoclonal anti-MOG antibodies 172 17 Neuroimmunological Molecules and Translational Medicine Table 17.1 Autoimmune channelopathies Targeted channel Clinical phenotype Clinical assay Nicotinic acetylcholine Myasthenia gravis Utilizes iodinated bungarotoxin receptor (nAChR) and immunoprecipitation Voltage-gated calcium Lambert–Eaton Utilizes iodinated conotoxin channel (VGCC) myasthenic syndrome and immunoprecipitation Aquaporin receptor Neuromyelitis optica Immunofl uorescence of brain slices; receptor transfected cell Voltage-gated potassium Limbic encephalitis; Utilizes iodinated dendrotoxin channel (VGKC) neuromyotonia and immunoprecipitation N -methyl-d -aspartate Limbic encephalitis Immunofl uorescence of brain slices; (NMDA) receptor receptor transfected cell are able to cause demyelination both in vivo (Dendroaspis), one of the deadliest snakes in the and in vitro, and can induce signifi cant disease world, and works by blocking voltage-gated in B-cell defi cient mice in whom the blood– potassium channels (VGKCs). Since dendrotoxin brain barrier is breached. The role of anti- binds with high affi nity to VGKCs, it can be used MOG antibodies is less clear in human to label VGKCs in immunoassays for anti-VGKC multiple sclerosis; there have been reports of antibodies, similar to the use of the krait toxin, both the importance of these antibodies [3 ] bungarotoxin, in labeling AChRs for anti-AChR and their lack of importance [4 ] . antibody testing for patients with myasthenia gravis (see Chap. 10 ). The use of animal toxins 2.2.7 Channels as Targets of for assaying for anti-channel and -receptor anti- Autoantibodies bodies is described in greater depth in Chap. 18 . An exploding area of research, discussed briefl y These toxins have been utilized primarily for in Chaps. 10 and 14 , is the elucidation of autoan- attempts to understand the structure and function tibodies to channels in neuroimmunological dis- of channels and receptors. Their utilization for ease. The prototype autoimmune channelopathy identifying autoantibodies has been an unantici- is, of course, myasthenia gravis, caused by pated, but welcome, offshoot of this research into autoantibodies to the acetylcholine receptor basic neuroscience. It represents an excellent (AChR) and discussed in Chap. 10 . However, a example of how basic research, seemingly unre- range of others have been described over the last lated to any clinical issues, can have direct rele- 10 years (see Table 1 7.1 ), and their mechanisms vance to disease. of action are actively being investigated. Most of them are felt to result in dysfunction by receptor modulation, cross-linking or internalization, thus 2.3 Neuroprotection: The Holy Grail mostly independent of immune effector mecha- of Translational Neurology nisms such as complement-mediated destruction or antibody-dependent cellular cytotoxicity. The Many neuroimmunological diseases, particularly autoantibodies in these diseases are directed MS, result in marked and progressive neuronal against parts of these receptors that are outside and myelin loss. These diseases would benefi t the cell, providing further evidence that the anti- from the development of neuroprotective drugs, bodies are indeed pathogenic. defi ned as agents which could ameliorate the Understanding of these channels and antibod- downhill progression of cell loss. Thus, a few ies to them has been advanced greatly by years ago, neuroimmunologists were excited by a improved availability of a variety of animal tox- large neuroprotection study of NXY-059 in acute ins summarized briefl y in Chap. 10 . Dendrotoxin ischemic stroke. This molecule, called a “spin comes from the venom of the mamba snake trap” molecule, was effective in in vitro systems References 173 in scavenging free radicals, which were felt to be munologists in the near future. The following important in accelerating ischemia and injury. statement of STAIR is sobering and applies Substantial in vitro and animal model work had equally well to MS as it does for stroke: been done to justify large, very expensive human The costs of modern drug discovery and develop- studies on this molecule. Guidelines for preclini- ment in most therapeutic disciplines have become cal studies had been developed in 1999 by the almost prohibitively expensive for any pharmaceu- Stroke Therapy Academic Industry Roundtable tical company, because investments in a single drug approximate $0.5 to $1.0 billion in Research (STAIR) which was anticipated to assist the phar- and Development activities. The bounty of new maceutical industry in bringing drugs with a high molecular targets derived from the recently unrav- probability of success to phase 3 studies. In addi- eled human genome poses unprecedented chal- tion, stroke seemed to be an ideal choice for neu- lenges to defi ne and validate the biology, pathology, and clinical usefulness of these targets for safe and roprotection studies since in stroke there is effective drug development. These new realities, sudden severe damage, and the prediction was increased by regulatory requirements for novelty that since the drug should have a substantial and differentiation of new therapies over those cur- effect, this treatment effect should have been rently available, creates unprecedented hurdles in developing new drugs. [6 ] readily seen in a short period of time. Unfortunately, in two very large studies, recruit- ing 5,208 patients, the drug was proven to be ineffective in humans [ 5 ] , prompting much hand- References wringing and attempts at explanations of why preclinical studies had not predicted the situation 1. TNF neutralization in MS: results of a randomized, in humans. The STAIR recommendations were placebo-controlled multicenter study. The Lenercept felt to have not been “closely followed.” Multiple Sclerosis Study Group and The University of This trial and the attempts to develop neuro- British Columbia MS/MRI Analysis Group. Neurology. 1999;53(3):457–65. protective drugs in Alzheimer’s disease, stroke, 2. Coles AJ, Compston DA, Selmaj KW, et al. Parkinson’s disease, and other neurological Alemtuzumab vs. interferon beta-1a in early multiple “degenerative” diseases have direct relevance to sclerosis. N Engl J Med. 2008;359(17):1786–801. neuroimmunology. There have been extensive 3. O’Connor KC, Appel H, Bregoli L, et al. Antibodies from infl amed central nervous system tissue recognize efforts to identify a neuroprotective agent in the myelin oligodendrocyte glycoprotein. J Immunol. most common and debilitating neuroimmunologi- 2005;175(3):1974–82. cal disease, multiple sclerosis, but no attractive 4. Owens GP, Bennett JL, Lassmann H, et al. Antibodies target has yet risen clearly above numerous poten- produced by clonally expanded plasma cells in multiple sclerosis cerebrospinal fl uid. Ann Neurol. tial molecules and processes. Current therapy of 2009;65(6):639–49. MS appears to have little or no effect on progres- 5. Diener HC, Lees KR, Lyden P, et al. NXY-059 for the sive damage to the CNS (for more information on treatment of acute stroke: pooled analysis of the SAINT this topic, see Chap. 7 ) . The need to develop safe I and II Trials. Stroke. 2008;39(6):1751–8. 6. Fisher M, Feuerstein G, Howells DW, et al. Update of the and effective neuroprotective agents for MS is stroke therapy academic industry roundtable preclinical likely the greatest challenge to research neuroim- recommendations. Stroke. 2009;40(6):2244–50. Neuroimmunological Diagnostic Tests 18 This chapter discusses diagnostic tests commonly generated from the history and examination. used by neuroimmunologists which are special- Usually, tests are done to confi rm diagnoses high ized for use in infl ammatory and infectious dis- on the differential diagnosis. There has been an eases. These are generally assays of the blood or increase in diagnostic testing over the past cerebrospinal fl uid (CSF), two bodily fl uids read- 30 years, most of it appropriate, but much of it ily accessible to the clinician. We will not discuss inappropriate and excessive. A test should not be the standard neurological tests performed by neu- ordered as an automatic, knee-jerk reaction. Tests rologists in evaluating neurological disease, such should be utilized according to their sensitivity, as the history, examination, imaging of the brain specifi city, and predictive value within a given by MRI or CT scanning, electroencephalography, population. Sensitivity is defi ned as how likely electromyography, nerve conduction studies, or the test will be positive in an affected individual; evoked responses, which are discussed in Chap. 2 . specifi city is how likely the test will be negative Consistent with its strong link to basic research, in an unaffected individual; and predictive value much of clinical neuroimmunology is dependent is how the test will perform in a certain popula- on laboratory assays. Researchers are constantly tion. This means if a test has a high sensitivity, trying to move assays developed in research labo- high specifi city, and it is used in a population ratories into the clinical arena, albeit with vary- which has a reasonably high likelihood of being ing degrees of success. As we have discussed affected, the predictive value of either a positive concerning the value of surrogate markers of dis- test or negative test will be very high. An exam- eases, it is one thing to be able to demonstrate ple is PCR of the CSF for herpes simplex genome. statistically robust sensitivity and specifi city of a Because this test has high sensitivity and speci- test for some aspect of disease, but it is another fi city, a positive HSV PCR has high predictive thing entirely to establish the clinical relevance value in a population of patients with fever, sei- of that fi nding. This means the clinical neuroim- zures, and impaired level of consciousness; i.e., munologist must have a fi rm understanding of the essentially, 100% of test-positive patients in this laboratory assays used in the fi eld. population will have active herpes simplex viral infection as a cause of their symptoms. In con- trast, a B orrelia burgdorferi serum ELISA (in the 1 General Considerations absence of immunoblotting, see below), which for Testing has high sensitivity but low specifi city in a popu- lation of patients in an endemic area with nonspe- Tests are obtained after history and physical cifi c symptoms, has poor predictive value. That examinations are performed to gain further infor- is, a very low percentage of individuals in a popu- mation after a differential diagnosis has been lation with nonspecifi c symptoms and positive A.R. Pachner, A Primer of Neuroimmunological Disease, 175 DOI 10.1007/978-1-4614-2188-7_18, © Springer Science+Business Media, LLC 2012 176 18 Neuroimmunological Diagnostic Tests Borrelia burgdorferi serum antibody tests will have active infection with B orrelia burgdorferi as 2 Blood Tests a cause of their symptoms. However, in a cohort which is better defi ned for clinical characteristics Blood is a body fl uid readily accessed by veni- of Lyme disease, the specifi city may be quite puncture, the procedure by which a needle is high. The usefulness of a test is dependent not inserted

into the vein and blood is withdrawn. only on its capacity to measure the surrogate The blood is evacuated into tubes which may marker but also on the way that the relevant pop- contain various materials which initiate the pro- ulation to be tested with it is defi ned. Tests should cessing of the sample in various ways. In the always be interpreted in the context of their sen- absence of the milieu of the vascular compart- sitivity, specifi city, and predictive value. Often ment, once the blood enters the glass tube, plate- this puts the onus on the neuroimmunologist to lets and thrombin cascade elements in the blood be able to defi ne a given test’s usefulness in vary- will result in clotting, a thickening and stickiness ing clinical situations. of blood components. Thus, if the blood is drawn into a tube without any chemicals that would inhibit the coagulation systems of the blood, clot- 1.1 Validation of Laboratory Tests ting will begin to occur almost instantly and over by Regulatory Authorities minutes to hours the blood will completely clot. The non-clotted portion is called serum; most In the USA, authorities have been mandated to tests of the noncellular components of the blood review and approve the performance of laboratory test serum. Tests of the blood for the cellular ele- tests that might aid in diagnosis or therapy of a par- ments, either white or red blood cells, require that ticular disease. While this does not result in a ruling the tube into which the blood is drawn contain an on the clinical usefulness of a given test, it does anticoagulant such as heparin sulfate, so that the assure that the process of running the assay are blood does not clot. If anticoagulated blood is subject to special quality control standards before separated into cellular versus noncellular frac- they are allowed to be utilized in clinical care. In tions, usually by centrifugation, the noncellular the USA, this process is regulated by the federal fraction is referred to as plasma. and state governments under the CLIA program (Clinical Laboratory Improvement Amendments) aided by the College of American Pathologists. An 2.1 Blood Tests for Infl ammation example is the anti-JC virus antibody assay which will likely aid in the management of patients with Some blood tests are ordered by neuroimmunolo- MS being considered for natalizumab therapy. This gists to assess markers in the blood indicative of test, developed and currently being run in a research an infl ammatory process which might affect the setting, has just recently been approved for clinical nervous system. None of these tests are highly use, and has become routinely available to clini- sensitive nor specifi c for infl ammation deriving cians (see discussion of JCV antibody in this from a particular immune response or a response chapter). After new tests become CLIA certifi ed, that defi nes a particular immunologically medi- and available to clinicians, another level of analysis ated disease, and usually serve as general indica- occurs, as clinicians determine the assay perfor- tors. They are especially helpful in systemic mance in a broad population of patients. Within a diseases such as the vasculitides or infections that few years after clinical availability of an assay, might affect the nervous system. Though these groups of clinicians perform studies evaluating may be targeting a particular organ system or tis- the assay’s sensitivity, specifi city, and predictive sue, such diseases often are associated with the value in patient populations and publish the studies release of infl ammatory mediators and cells into in the medical literature. Over time the new test the vascular compartment, and are thus amenable takes a place in clinical practice. to assays to detect their presence. 2 Blood Tests 177 2.1.1 Sedimentation Rate Chap. 1 . A clinical example of the value of such Sometimes called erythrocyte sedimentation rate a test is in HIV: later stages of HIV infection are (ESR) or Westergren sedimentation rate (WSR), characterized by a profound depletion in CD4 this test, when elevated, indicates that infl amma- cells in the blood so that the CD4/CD8 ratio in tion is present somewhere in the body, often as a the blood, which is usually between 1 and 4, is generalized infl ammatory disease, infection, or markedly lowered, sometimes to as low as 0.1. malignancy. The sedimentation rate measures Another important clinical use of determining how far red blood cells in blood migrate along a these markers is in the case of lymphoma in the glass surface. The precise molecular pathways by CNS (Chap. 14 ), since CNS lymphomas are which the sedimentation rate are increased in almost without exception, B-cell malignancies, infl ammation are unknown. In some infl amma- and the demonstration that most of the cells in the tory diseases limited to the CNS, such as multiple CSF have B-cell markers, i.e., either CD19 or sclerosis, the ESR is not generally increased, CD20, supports the diagnosis of lymphoma. even when CNS infl ammation is extensive. The To determine CD markers in a population of reasons for this fi nding are unknown, but one cells, derived either from the blood or CSF, a expects that for an ESR blood test to be positive, methodology called fl uorescence-activated cell most likely there must be ready communication sorting (FACS) is used. After cells are exposed to between the infl amed area and the blood circula- fl uorescence-tagged monoclonal antibodies reac- tion, and this access is limited by the blood–brain tive to a certain CD marker, they are allowed to barrier in such diseases of the CNS as MS. pass through a narrow tube in single fi le, and the amount of fl uoroscence that each individual cell 2.1.2 White Blood Cell Count Elevation produces due to the amount of tagged MAB adher- A complete blood count (CBC) measures the ent to it is assayed as it passes by a sensor. The number and kinds of cells in the blood, and an population is analyzed for how many cells contain elevation in the number of white blood cells in fl uorescence, which identifi es how many cells the blood usually indicates infl ammation. have the CD marker. Modern FACS machines can analyze many markers with different fl uorescent dyes at the same time, allowing identifi cation of 2.1.3 Surface Markers of White multiple markers on the same cells Blood Cells The neuroimmunologist is frequently interested in determining the possible disease-specifi c pat- 2.2 Blood Tests for Specifi c tern of white blood cell types in the peripheral Immunity to Pathogens blood or CSF. The CBC provides a count of neu- or Autoantibodies trophils, lymphocytes, monocytes, eosinophils, and basophils, which are differentiated by size Automated technologies and the advent of molec- (charge) in automated counters and by morphol- ular biology have resulted in markedly improved ogy on microscopic visual exam. Additional methodologies for detecting antibodies directed information may be obtained by identifying mol- against a wide range of targets. Many antibody ecules on the surface of the white cells, called assays utilize the ELISA methodology that allows surface markers, and have been categorized noso- high throughput and rapid results. ELISA meth- logically as different cluster of differentiation ods frequently require confi rmation with a sec- (CD) molecules. This is especially important for ond assay such as immunoblotting or western differentiation of T lymphocytes, which express blotting (see Inset 1 8.1 ). Another commonly used the CD3 antigen, from B lymphocytes, which name for such testing for antibody in the blood express CD19 or CD20 and in identifying how when it pertains to immunity to pathogens is many T lymphocytes are “helper”(CD4) relative serology. Assays for autoantibodies can include to “cytotoxic”(CD8), as briefl y explained in any of the above methodologies and also may be 178 18 Neuroimmunological Diagnostic Tests immunohistochemical or immunofl uorescence assays, such as the aquaporin antibody screen Immunoblotting, sometimes called west- (see below), in which processed tissues are used ern blotting, is a technique in which the mix- as the antigen. ture of proteins of the pathogen is separated on a membrane utilizing a methodology called electrophoresis. In electrophoresis, molecules of complex solutions are sepa- Inset 18.1 ELISA/Immunoblotting rated in solid phases by movement through Testing for antibodies to B orrelia burgdor- an electrical fi eld; larger molecules move feri is an example of how testing for anti- slower than smaller molecules, and markers bodies to a pathogen is performed in the can identify the separated molecules, usu- clinical laboratory. The word ELISA stands ally proteins, by size. Thus, a “41 kDa band” for enzyme-linked immunosorbent assay, identifi es antibodies binding to a 41,000 in which the assay is done completely in molecular weight protein, which in B. burg- solid phase. There are many modifi cations dorferi , is a protein found in the fl agella of of the ELISA; the one most commonly the spirochete. This fl agellin is found in used for detection of antibodies to a patho- other bacteria, and since humans become gen is the indirect ELISA in which, in the exposed to many bacteria, antibody to the case of B. burgdorferi -specifi c antibodies, 41 kDa protein is a relatively nonspecifi c sonicated spirochetes are incubated in the antibody population found in a large per- plastic wells in an alkaline buffer, which centage of the general population. Other leads to adherence of the molecules to the proteins, such as the 39 kDa protein are plastic. After washing off unbound mole- more specifi c for B . burgdorferi . Thus, a cules, the patient’s serum is incubated on positive western blot requires reactivity to the plate, and antibodies with high affi nity multiple B. burgdorferi proteins. Most for B. burgdoreri molecules bind to these patients with Lyme neuroborreliosis have molecules on the plate. After unbound had prolonged exposure to the spirochete, material is washed off, the antibodies have developed high levels of antibody, and bound to the plate are detected by an anti- will react to more than the fi ve bands immunoglobulin antibody which has been required for a positive IgG immunoblot. chemically conjugated to an enzyme; this chimeric molecule is often called the ELISA conjugate. After unbound conju- gate is washed off, the enzyme moiety of the conjugate remaining bound to the 2.2.1 Serum Antibodies patient’s immunoglobulin on the plate Pathogens reacts with an ELISA substrate, which Detection of antibodies to a pathogen indicates results in the development of a color. This exposure of the immune system to the pathogen color reaction can then be read by a spe- at some point in the life of the individual and may cialized spectophotomer, an ELISA reader. not necessarily be able to demonstrate the cur- Quantitation of anti-B . burgdorferi anti- rent, actual presence of the pathogen. Whether body can be performed by quantitation of exposure and concurrent infection are identical color developed, since it will be directly and whether a positive test indicates that the proportional to the amount of enzyme, pathogen is causative of the disease process which is directly proportional to the depends on the pathogen. patient’s anti-B . burgdorferi antibody For instance, positive anti-HIV antibodies bound to the plate. almost always indicate the presence of the patho- gen, HIV, since an individual who is HIV positive 2 Blood Tests 179 is highly unlikely to ever be able to completely being treated with immunosuppressive clear the pathogen from the body. In contrast, in medications. Lyme disease, many individuals can continue to ELISAs to detect the presence of anti- be antibody positive for years after extensive JCV antibodies have been developed for antibiotic treatment and complete clearance of clinical use, and, as of late 2011, have just the pathogen. In chronic viral infections which become be available to clinicians as routine are common in the general population such as the clinical assays. Thus, a negative JCV anti- JC, herpes, CMV viruses, a positive antibody test body assay identifi es a patient population at indeed indicates active infection, but the active very low risk of developing PML when infection is controlled by the body’s immune immunosuppressive drugs such as natali- response, and the vast majority of infected zumab are used, relative to the JCV-positive individuals have no clinical disease referable to population. The percentage of adults who

the active infection. For another pathogen, are seropositive in the normal population Clostridium tetani , the causative agent of tetanus, ranges from 60 to 80%, depending on meth- almost all individuals have detectable serum odology [ 1 ] . antibodies to C . tetani due to their having received (iii) West Nile Virus (WNV) . WNV is a fl avivirus tetanus vaccinations. Of course, none of these which caused an epidemic of meningoen- individuals has active infection with the bacteria. cephalitis in the USA in 2003, and has con- Thus, in these four infections—HIV, B orrelia tinued to be associated with sporadic burgdorferi , JCV, and Clostridium tetani —the outbreaks. Serology is the diagnostic assay presence of a positive anti-pathogen antibody of choice in this infection since the virus is assay in the serum means something very only detectable in the blood for a short time, different. almost always prior to the onset of symp- toms, and by the time the patient is symp- Viruses tomatic the virus has been cleared from the (i) H IV . Improved methodologies have allowed blood. The IgM response is dominant in this HIV testing to become much easier than they infection; persistent IgM positivity can were only a decade ago. OraQuick and simi- remain for many months after clearance of lar point-of-care tests are anti-HIV antibody the encephalitis. tests that provide results in less than half an (iv) Common viruses in the population . Adults are hour. Oral fl uid is obtained, mixed with a infected with a variety of viruses, and in many solution, and the results are read from a instances, these infections are persistent, lead- stick-like testing device. The assay is highly ing to persistently positive antibodies in the reliable and is used widely as a point of care serum. Examples include Epstein–Barr virus screening assay. ELISAs and immunoblots (EBV) and cytomegalovirus (CMV). Although are additionally used. a role has been suggested for EBV in diseases (ii) J C virus (JCV) . JCV is the causative agent such as chronic fatigue syndrome (CFS) or of progressive multifocal leukoencephal- fi bromyalgia, the evidence for this is meager. opathy (PML), and increasingly of concern The evidence for the role of EBV in HIV- in MS patients treated with a variety of new associated CNS lymphoma or CMV in HIV- agents (see Chaps. 7 and 19 ). The vast associated polyradiculitis is stronger, but majority of individuals who are infected determination of serum antibody lends little with JCV have asymptomatic medically to the diagnosis or management of these syn- unimportant infections, well controlled by a dromes. There has been some interest in EBV normally functioning immune system, but as a possible pathogen or co-pathogen in mul- JCV can become reactivated to cause PML tiple sclerosis. At this time, there appears be (see Chap. 12 ) if the patient becomes immu- little role for serum anti-EBV or -CMV test- nosuppressed either by HIV infection or by ing in neuroimmunological disease. 180 18 Neuroimmunological Diagnostic Tests Bacteria but antifungal antibodies in the serum are some- Most infections with bacteria are diagnosed by times helpful, especially in CNS histoplasmosis culture, but for some so-called fastidious organ- or coccidoidomycosis. Most fungi, however, can isms, such as spirochetes (syphilis and B orrelia be cultured from the CSF. burgdorferi ) and mycobacteria, culture is a low- yield assay, and other assays are clinically more Autoantibodies important. For spirochetes, serology is the assay Autoantibodies, defi ned as antibodies against of choice, while for M ycobacteria tuberculosis , host antigens, can be detected in a wide variety of skin testing or PCR are the tests of choice. The neuroimmunological diseases. Some autoanti- diffi culties in making the diagnosis of tuberculo- bodies appear to be pathogenic, while most are sis within the CNS, discussed in Chap. 12 , are biomarkers of an underlying disease process. legendary. Even though serology is the preferred means of diagnosis in both neurosyphilis and Reaginic Antibody Tests for Syphilis Lyme neuroborreliosis (LNB), the type of anti- and Antiphospholipid Antibodies spirochetal antibody tests used for neurosyphilis As mentioned in Chap. 13 , autoantibodies to and neuroborreliosis are very different. phospholipids (the VDRL or RPR) reliably In Lyme neuroborreliosis, an ELISA, coating appear during syphilis and are excellent markers plates with lysates from sonicates spirochetes of infection. Thus, if the infection is treated, the grown in culture, is the fi rst step, which, if posi- titers of serum VDRL or RPR drop, and usually tive, is followed by an immunoblot (see Inset 18.1 , clear over time. Antiphospholipid antibodies ELISA/immunoblotting). detected by the VDRL or RPR assay or by the I n contrast, in neurosyphilis, the fi rst fast, anticardiolipin ELISA are also a feature of pri- inexpensive screening test is a reaginic test, a mary or secondary antiphospholipid antibody VDRL or RPR, autoantibody tests described in syndromes. Chap. 13 , based on autoantibodies to phospholip- ids which develop during infection with Treponema pallidum . If this screening assay is Antinuclear Antibodies and Other negative, there generally is no need to proceed Autoantibodies in Lupus and Related with a second level test. However, if it positive, a Rheumatological Disease specifi c treponemal antibody assay needs to be In SLE, the autoimmune response generates performed, since there are many causes of false- autoantibodies to the components of the nuclear positive reaginic antibody tests. These false-pos- membranes or nucleoplasm of particular cells, itive assays, sometimes referred to a biological commonly called antinuclear antibodies (ANA). false positive (BFP), are frequently seen in sys- Patients with different types of autoimmune dis- temic lupus erythematosus (SLE) or other auto- orders frequently have ANAs but their types are immune diseases, as described in Chap. 13 , but different, since antigens to which they bind are can also be caused by other infections such as different. For instance, autoantibodies in Sjogren’s TB, malaria, hepatitis viruses, varicella zoster, or syndrome, discussed in Chap. 8 as a mimic of measles, or even by cancers such as lymphoma. MS, are directed against nuclear antigens called The second level tests are antibody assays in Ro and La, sometimes called SS-A and SS-B. which Treponemal material serves as the antigen, e.g., fl uorescent treponemal antibody (FTA) or Autoantibodies to Neurological Antigens the T reponema pallidum hemagglutination This area has attracted increasing interest in the assay (TPHA). last decade, primarily because of a number of discoveries, including the documentation of Fungi autoantibodies to aquaporin-4 receptors in neuro- The diagnosis of CNS fungal infections is ideally myelitis optica (NMO), and the discovery of a performed by culture, or identifi cation of fungal number of new paraneoplastic syndromes that antigen (e.g., cryptococcal antigen, see Chap. 12 ), appear to be autoantibody mediated. 2 Blood Tests 181 Fig. 18.1 Schematic representation of a brain capillary at the blood–brain barrier. Aquaporin-4 is expressed at the end feet processes of the perivascu- lar astrocytes, providing a pathway for brain edema clearance at the level of blood–brain barrier (i) A quaporin-4 in NMO . In NMO, discussed in performed by reacting patient’s sera with Chap. 8 , antibodies to aquaporin-4 are found mouse cerebellar slices [3 ] , but now the assays in the serum of the majority of patients. are performed using cell lines transfected Aquaporin-4 (Fig. 17.1 ), a membrane pro- with aquaporin-4 receptors. The test is not tein, is localized to the endfeet of astrocytes perfect for defi ning the clinical syndrome; (Fig. 1 8.1 ) and is thought to constitute part of the sensitivity is 50–80% depending on the the blood–brain barrier; why this protein has laboratory, but the specifi city is quite high, in become an antigenic target in NMO is some studies over 90%. Thus, a positive test unknown. Patients with NMO have a pheno- usually indicates that the patient has NMO, but type of an MS-like disease consisting of a negative test does not rule out the diagnosis. extensive and continuous spinal cord lesions, (ii) AChR . The measurement of anti-AChR anti- and/or optic neuritis, often have normal brain bodies in the serum is a very helpful diag- MRI scans and negative oligoclonal band nostic assay for myasthenia gravis. The testing. The serum antibodies are thought to methodology used is generally an immuno- be pathogenic, a hypothesis supported by precipitation assay, in which anti-AChR passive transfer experiments in experimental antibodies in the serum of MG patients bind animals [2 ] , in which antibodies from patients to and precipitate in vitro AChR from mus- with NMO and positive anti-aquaporin anti- cle homogenates after the AChR has been bodies induced exacerbation of EAE in rats. labeled with radioactive bungarotoxin (see The antibodies themselves were not patho- Chap. 10 for information about bungaro- genic in the absence of EAE since they did toxin). This immunoprecipitation assay, not cross the blood–brain barrier. Severe dis- which was developed in the 1970s, was the ease required the presence of both a patho- fi rst using snake toxins for labeling a neuro- genic antibody in the serum and breakdown logical receptor. It has served as the proto- of the blood–brain barrier induced by EAE. type for the development of a wide variety The same combination of factors may be of assays for anti-neurological receptor anti- operative in human NMO in which both a bodies using radioactively labeled snake breakdown in the blood–brain barrier and toxins which specifi cally bind receptors. pathogenic antibodies in the blood may need In the case of anti-AChR receptors in to be present to result in disease. myasthenia gravis, bungarotoxin has an Initially, when fi rst described, the assay extremely low affi nity constant for AChR, for aquaporin-4 receptor antibodies was which means that the binding of bungarotoxin 182 18 Neuroimmunological Diagnostic Tests to AChR is so strong that the conditions of dendrotoxin which labels voltage-gated the assays will not separate them and thus potassium channels (VGKCs) in neuromyo- the radioactively tagged bungarotoxin essen- tonia and limbic encephalitis, and the snail tially strongly labels AChR. Once the AChR toxin conotoxin which labels voltage-gated is labeled, the patient’s serum is added to the calcium channels (VGCCs) in Lambert-Eaton muscle homogenates and anti-AChR anti- myasthenic syndrome (LEMS). bodies bind to the labeled AChR. The next Another approach to testing for anti- step is the addition of an anti-human IgG receptor or anti-channel antibodies is to antibody which can precipitate antibody, express the receptor in a cell line such as and preferentially that antibody which is oocytes or fi broblasts and then test for bind- bound to a large molecule-like AChR. The ing of immunoglobulin from patient’s serum precipitated material is washed free of to the cells. This has proven quite successful unbound radioactive bungarotoxin and the for anti-aquaporin receptor antibodies in remaining radioactivity measured in the pre- NMO and has provided for more reliability cipitate is proportional to the levels of anti- than the immunofl uorescence assays with AChR antibodies. The test is highly specifi c whole brain tissue. for myasthenia gravis, but a substantial proportion of MG patients, 15–50% depend- ing on stage of the disease, are seronegative, 2.3 Blood Tests for Detecting i.e., negative on this test for anti-AChR Specifi c Pathogens antibody. (iii) Neuronal Antigens, Including Ion Channels 2.3.1 Cultures and Receptors, in Paraneoplastic Neuro- The standard technique for identifying an infec- logical Disorders (PNDs) . A full discussion tion in any body fl uid is by sampling the body of assays for paraneoplastic antibodies is fl uid, injecting the sample into culture medium, beyond the scope of this chapter. A recent and identifying the responsible bacterium in the review of paraneoplastic neurological disor- culture medium after it has replicated. Both bac- ders (PNDs) [4 ] identifi es 17 different teria and fungi can generally be readily identifi ed autoantibodies. The oldest and most well- in this way. studied autoantibodies in PND are anti-Yo (see clinical vignette of paraneoplastic cere- bellar degeneration in Chap. 1 4) and anti-Hu 2.3.2 Polymerase Chain Reaction (PCR) antibodies. These bind to antigens in cere- PCR takes advantage of the ability of DNA poly- bral neurons and Purkinje cells (see Chap. 2 ) . merase to copy single-stranded DNA, and uses Initially, the reactivities were found by react- primers, short complementary sequences of ing serum from patients with PNDs with tis- DNA, to identify the

particular segment of the sue slices, similar to the screening tests DNA which will be copied. What is thus needed which detected anti-aquaporin 4 antibodies for the test to work appropriately is correct in NMO (see above). Many of these assays sequences of the organism and intact DNA from are now performed with purifi ed antigens the organism; if the organism is an RNA virus, it rather than whole tissue. can be converted into DNA by using the enzyme For testing for some of the anti-channel reverse transcriptase; the PCR for RNA frag- or anti-receptor antibodies, animal toxins are ments then is called an RT-PCR. The assay is used to label the receptor protein prior to an usually quite sensitive and specifi c. The PCR immunoprecipitation assay in a methodology technique was invented and initially developed similar to the anti-acetylcholine receptor by Kary Mullis (see Inset 1 8.2 ). assay. The two most commonly used radio- The diagnostic PCR most commonly used in active labeled toxins are the mamba toxin neuroimmunology is the detection of HIV in the 3 Cerebrospinal Fluid (CSF) 183 There are a few potential problems with the use Inset 18.2 Kary Mullis and PCR of CSF for diagnosis. First is the potential false Kary Mullis received the Nobel Prize in positivity in serological assays caused by high 1993 for his discovery of the PCR, which levels of immunoglobulin. CSF generally has very revolutionized biology. Mullis’ career has low immunoglobulin levels because of the blood– epitomized the ups and downs of many sci- CSF barrier, but in a number of infl ammatory con- entists who can work for decades on proj- ditions the immunoglobulin levels can rise to high ects which can eventually be dead ends, or levels. Since cutoffs for positivity for reactivity on be huge successes which change the nature antibody assays are dependent on normal CSFs of science. After his graduate education with low immunoglobulin levels, and nonspecifi c Mullis left science to be a fi ction writer, but binding increases with higher immunoglobulin later returned to science working a medical levels, low-level false-positive assays are fre- school. He then become a baker for a few quently seen in infectious or infl ammatory condi- years, but ultimately got a job with Cetus tions (see Inset 18.3 ). Clinical vignette-Liver Corporation in California as a chemist. The damage as a result of a medical error in interpreting idea for PCR came to him while he was CSF antibody assays. Secondly, it is not unusual to driving one night, and Cetus allowed him have a so-called “traumatic tap” when lumbar punc- time to pursue his idea. After some disap- tures are performed, resulting in blood vessels pointing trials, the idea eventually bore being nicked in the process of inserting the needle. fruit, and he received a $10,000 bonus from This results in some blood leaking into the CSF Cetus. Mullis has had some unusual ideas samples. Unfortunately, the presence of blood con- since then, discussed in his 1998 autobiog- tamination in the CSF lessens the utility of the CSF raphy, Dancing Naked in the Mine Field, as a diagnostic tool, and all possible steps should including a business selling jewelry con- be taken to ensure that the spinal tap is performed taining amplifi ed DNA of celebrities and cleanly. An example of an assay that is made inac- an encounter with an extraterrestrial in the curate by a contaminated tap is one which tests for form of a fl uorescent raccoon. an “antibody index” in which levels of antibody levels in the CSF than the blood are measured rela- tive to concentration of Ig in the blood, with the control for BBB permeability being the albumin in the two compartments. These assays are almost blood. This test both directly tests for the pres- impossible to interpret with blood contamination ence of the virus, and, if the test is positive, also of the CSF since the normal amount of IgG in the quantitates the concentration of the virus in the blood is 300–1,000 times that of the CSF. Thus, the blood. The ease with which HIV can be quanti- presence of even a small amount of blood in the tated in blood revolutionized the fi eld of HIV CSF will change the index. therapeutics since it allowed the rapid determina- tion of viral load, which could be readily targeted by candidate therapies. Inset 18.3 Patient Vignette: Liver Damage as a Result of a Medical Error in Interpreting CSF Antibody Assays 3 Cerebrospinal Fluid (CSF) A 35-year-old woman was referred to our medical center in 2007 for management of CSF is usually obtained via a lumbar puncture. “severe treatment-refractory Lyme neuro- Assays of the CSF are very helpful in neuroimmu- borreliosis” to determine whether “contin- nology since the CSF circulates throughout the CNS ued antibiotic therapy was necessary given and around large areas of the PNS. CSF analysis is the risks.” generally a necessary part of the diagnostic workup in patients with neuroimmunological disease. (continued) 184 18 Neuroimmunological Diagnostic Tests Inset 18.3 (continued) Author’s note . Every laboratory assay must She well until 2004 when she developed left be assessed for its sensitivity, specifi city, and optic neuritis which resolved over a few predictive value in the population in which months with no therapy. In March 2006, she testing occurs. A positive test at a low level developed numbness in her left arm which for anti- B. burgdorferi antibody in the CSF resolved in a few weeks with no therapy. In has a high sensitivity rate, but a very low 2007, she developed some ataxia and was specifi city, and very low predictive value in evaluated by a neurologist who felt that she patients who have high-IgG levels in the had Lyme disease based on a positive anti-B . CSF. This is because immunoglobulin mole- burgdorferi CSF antibody assay. He referred cules are “sticky,” i.e., like many proteins her for treatment to an infectious disease they have multiple interactions with other s pecialist who treated her with ceftriaxone 1 g molecules which result in some nonspecifi c twice per day for 5 months, during which she binding. Binding of one molecule to another developed abdominal pain, and was found to can be measured by dissociation constants, have severe cholecystitis and moderate hepa- which measure how strongly one molecule titis both felt to be secondary to the ceftriax- binds to another. This measurement is one. There was no history of rash, arthritis, affected by such forces as electrostatic inter- facial palsy, or symptoms of meningitis. actions, hydrogen bonding, hydrophobic, The CSF results were reviewed and, in and van der Waals forces. Thus, for any par- addition to showing a low-positive anti-B . ticular binding of an antibody to an antigen, burgdorferi CSF antibody assay was positive some will be nonspecifi c binding and some for OCBs. IgG index was not sent. will be specifi c binding. Affi nity is the On exam, she had mild optic atrophy, dif- inverse of dissociation so an affi nity constant fuse hyper-refl exia, a positive Lhermitte’s sign for an antibody binding to its antigen is the (fl exion of the neck causing tingling sensations inverse of the dissociation constant. As the into the arms or legs), and mild cerebellar concentration of an immunoglobulin in a ataxia. An MRI of the brain showed multifocal particular solution increases, it will be more white matter disease consistent with multiple likely to bind to other molecules nonspecifi - sclerosis; one white matter lesion enhanced cally. Thus, most binding assays are highly with contrast. Blood serologies for anti- B. concentration dependent. For blood tests, burgdorferi antibodies were negative. this is not usually an issue since the immuno- A lumbar puncture was repeated, showing globulin concentration in the blood of most once again oligoclonal IgG bands and a humans is highly regulated and is mostly the low-positive anti-B . burgdorferi antibody. same from one individual to another. However, the IgG index was exceedingly However, CSF immunoglobulin concentra- high with a very high CSF IgG. The anti-B . tions is highly variable from one disease pro- burgdorferi antibody index was negative cess to the next and can be much higher in indicating that the “positive” CSF anti-B . patients with MS or other CNS infl ammatory burgdorferi was a false positive, because of processes than in normals. Thus, assays the very high CSF IgG concentration. which measure binding of immunoglobulin A diagnosis of multiple sclerosis was made, in the CSF to the spirochete B. burgdorferi , ceftriaxone therapy was terminated, her as well as other antigens, will frequently be abdominal pain stopped, and her liver func- false positive at a low level in patients with tion tests slowly returned to baseline. Her sub- MS. This is the reason antibody indexes are sequent clinical course was consistent with helpful, because binding is corrected for the MS, and interferon-b therapy resulted in no relative concentrations of immunoglobulin in adverse effects. the fl uids. 3 Cerebrospinal Fluid (CSF) 185 3.1 Antibodies in the CSF 3.1.1 General Approach to Determination of Intrathecal Antibody Production of Any Specifi city The diagnosis of many neuroimmunological dis- eases is aided by measuring immunoglobulin populations within the CSF. There are two broadly defi ned types of assays: n onspecifi c , measuring IgG generally, or s pecifi c , which measure anti- bodies of a particular antigenic specifi city. In both, the contribution of immunoglobulin from Fig. 18.2 A Reibergram demonstrating intrathecal IgG the blood needs to be determined, since there is an production in a mouse model of MS [9 ] . In this Reibergram equilibrium of CSF IgG with blood IgG. [ 5 ] , CSF/serum indices for IgG and albumin are displayed on a log– log scale, demonstrating intrathecal synthesis of IgG. The x -axis is the Q-albumin, or albumin index (CSF QIgG, Qalbumin, and the IgG Index albumin/serum albumin) in which the upper limit of nor- In the normally functioning CNS, the ratio of IgG mal is 8. The y -axis is the Q-IgG, or IgG index (CSF IgG/ concentration in the lumbar CSF relative to that serum IgG), in which the upper limit of normal is 3. Each of blood is about 1/300 to 1/1,000; this ratio is point is the CSF analysis of a single mouse with Theiler’s virus-induced demyelinating disease. The albumin and referred to as Q . In normal circumstances, all IgG IgG indices are multiplied by 1,000 for clarity; IgG in the of this IgG is derived from IgG in the blood, and CSF is approximately 1/1,000 that of the serum none is produced within the CNS, since there are no plasma cells producing IgG within the CNS unless there is an infl ammatory CNS process. these relationships are sometimes called When the blood–CSF barrier is disrupted, such as “Reibergrams” after Hansotto Reiber, a German in acute meningitis, the IgG concentration in the investigator who has popularized the application CSF increases as more IgG from the blood is able of these analyses to neuroinfl ammatory diseases to pass into the CSF. In contrast to meningitides, [ 5 ] (see Fig. 1 8.2 ). The Reibergram can provide not all CNS infl ammatory processes result in sig- more information to a clinician than the IgG nifi cant disruptions in the blood–CSF barrier; index, because the IgG index does not provide e.g., in multiple sclerosis there is usually not ade- information about the integrity of the blood–CSF quate diffuse change in blood–CSF barrier to barrier. markedly change immunoglobulin concentra- tions and most of the IgG present in the CSF in Assaying CSF for Oligoclonal Bands MS is produced by B cells within the brain. Thus, Assaying CSF for oligoclonal bands (OCBs) is a in an infl ammatory process, it may be important test of the CSF in which proteins are separated by to determine whether the elevated IgG in the CSF an electrophoretic technique and then identifi ed is produced within the CNS, or simply as a con- as IgG usually by an anti-IgG antibody. Similar sequence of an impaired blood–CSF barrier. This IgGs group together and a specifi c immune can be done by comparing the IgG ratio, i.e. Q , IgG response is characterized by such aggregation,

so to a ratio of albumin in the CSF relative to the that an immune response in which plasma cells in serum, called Q . Albumin is another large albumin the brain produce antibody can be identifi ed by protein found at a 300–1,000-fold concentration positive OCBs in the CSF. Since some OCBs can higher in the serum than the CSF. The IgG index “leak” into the CSF from the blood, a truly posi- is derived from Q divided by Q . Thus, if IgG albumin tive OCB analysis is one in which OCBs are there is a production of IgG within the CNS, the detected in the CSF which are not detected in IgG index will be higher than 1. Graphs plotting blood. The test is particularly helpful in multiple 186 18 Neuroimmunological Diagnostic Tests sclerosis in which OCBs specifi c for the CSF neuroborreliosis. The absence of signifi cant anti-B . using optimal techniques are present in over 90% burgdorferi antibody in the CSF is evidence of patients with MS, frequently when no other against the diagnosis of Lyme neuroborreliosis. immune test is abnormal in CSF or blood. This fi gure of over 90% sensitivity for OCBs in MS Viral Antibodies comes from studies in which there is careful Prior to the development of PCR to detect viruses, attention to details of the OCB assay. In many antibody assays were frequently the only way to practice settings in the USA, however, CSF anal- detect the presence of the viruses in the CNS. ysis is not performed optimally, and the predic- However, this approach has many false negatives, tive value of the assay will subsequently be lower. and often by the time viral antibodies are detected In a paper presented at the Consortium of MS in the CSF, the pathogen has been cleared, or has Centers meeting in 2010, Rauchway et al. con- caused major injury. In contrast, since viruses ducted a survey of 225 laboratories throughout usually have a large copy number relative to other the USA and found that only 61(27%) were per- types of infections and PCR is a sensitive assay forming OCB testing according to consensus for the nucleic acid of a virus, PCR has become conference recommendations [6 ] . Physicians car- test of choice in the CSF for detecting viral infec- ing for MS patients should be cognizant of the tions in the CNS. CSF viral antibodies are now quality of the assays in the CSF available to them, rarely used. since, with acceptable CSF OCB assays per- formed for the diagnosis of MS, a “negative assay strongly suggests an alternative diagnosis” [6 ] . 3.2 Detection of Pathogens 3.1.2 Antigen-Specifi c Tests of the CSF in the CSF Reaginic Tests for Syphilis Neurological involvement in syphilis can be dif- 3.2.1 Polymerase Chain Reaction fi cult to detect, and a positive CSF reaginic anti- in the CSF body (see reaginic antibody above) determines Both for PCR and culture, the accuracy of the test that Treponema pallidum has invaded the CNS is decreased if blood leaks into the CSF during and resulted in plasma cells within the CNS pro- the LP. Thus, obtaining an “atraumatic” spinal ducing reaginic antibodies. Thus, patients with tap is highly desirable. Some tissue proteins can neurosyphilis will have a positive CSF VDRL or interfere with function of the DNA polymerase, CSF RPR; sometimes reaginic tests can be posi- but the CSF is usually a remarkably “clean” body tive in the CSF when they are not positive in the fl uid in this regard and excellent sensitivity is blood. obtained from CSF PCRs, as long as signifi cant amounts of blood do not contaminate the CSF. If Lyme Disease there are very few copies of the pathogen, or if Infection with Borrelia burgdorferi resulting in the organism is an RNA virus that requires reverse Lyme neuroborreliosis is an increasingly com- transcriptase to convert the RNA to DNA, sensi- mon infection in many parts of the world, and tivity may be less than optimal. Thus, B orrelia cannot be readily detected by assays testing for burgdorferi generally has a very low copy num- the presence of the pathogen. An antibody index ber in the CSF resulting in relatively low sensitiv- in which a ratio of the level of anti- B. burgdorferi ity of CSF PCR in Lyme neuroborreliosis. IgG antibody in the CSF relative to that of serum is determined and compared to the relative 3.2.2 Culture of the CSF amounts of total IgG is a very helpful assay for The clinical situation usually dictates what type the detection of Lyme neuroborreliosis. This of cultures is ordered. A patient presenting with a antibody index is the test of choice for Lyme hyperacute meningitis, with a CSF showing large 4 Tests of Immune Function 187 numbers of polymorphonuclear leukocytes and a 3.2.5 Fungi positive gram stain consistent with a pyogenic Cryptococcus, coccidioides, aspergilla, and meningitis, requires bacterial cultures. In a patient histoplasma are not rare causes of chronic menin- with a subacute or chronic meningitis, and CSF gitis (see Inset 12.3 for coccidioidal meningitis); mononuclear pleiocytosis, the CSF should be CSF PCR can be helpful for their diagnosis, sent for fungal cultures as well as a cryptococcal although culture is often more easily available. antigen determination by latex agglutination. In addition, it is helpful to obtain an extra tube of a 3.2.6 Other Pathogens minimum of 2 cm 3 CSF for short-term storage in Many other infections in the CNS are not associ- a refrigerator, because frequently more testing is ated with spillage of pathogen into the CSF that is indicated after the fi rst round of results are adequate to allow detection of the organism by obtained. Having an extra tube allows more PCR. This is especially true if meningitis is not a directed tests to be performed without the need prominent part of the infection, and the organism is for a repeat LP; for most types of cultures, an contained in the parenchyma of the brain. Walling overnight incubation at 4°C will not signifi cantly off of the infection within the parenchyma— e.g., decrease the culture yield. Thus, the morning abscess formation—reduces ascertainment even after the initial testing of the CSF, more CSF further. Examples of organisms implicated in such could be sent for other organisms if within the situations include toxoplasma and T aenia solium differential. (the cause of cysticercosis). 3.2.3 Viruses 4 Tests of Immune Function The diagnosis of viral infections of the CNS has been revolutionized by the availability of PCR to Increasingly patients with neuroimmunological detect viral infections. In the past, the diagnosis diseases are being treated with immunosuppres- of these infections was frequently very diffi cult, sive medications as reviewed in Chap. 19 . but now the sensitivity and specifi city of viral Monitoring for immune function is in its infancy. detection in the CSF is so high that many neu- It is likely that there will be signifi cant advances roimmunologists are hesitant to make the diagno- in this area as immunosuppressives are increas- sis of viral infections such as herpes simplex ingly used for chronic diseases. encephalitis, varicella zoster-associated vascul- opathies, or PML without positive CSF PCRs for the virus. However, unlike culture techniques, in 4.1 Humoral Immunity which one can simply order “bacterial culture” or “fungal culture,” in PCR, specifi c sequences of a Total immunoglobulin levels in the serum or virus are utilized so one must request a PCR of measurement of specifi c isotypes can be helpful the specifi c pathogens which are high on the list to detect potentially dangerous impairments of of likely organisms. humoral immunity. This can be especially impor- tant in therapies targeting B cells. In a 1-year 3.2.4 Tuberculosis phase 2 study of the anti-CD20 therapy, ritux- Mycobacterium tuberculosis is the most common imab, in MS, a single course of therapy resulted cause of diffi cult-to-diagnose chronic meningitis, in signifi cant incidence of lowered immunoglob- and PCR has proven very helpful in its diagnosis. ulin levels, particularly IgM [8 ] . Some investiga- It should be strongly suspected in patients who tors are recommending that antibody responses have meningitis with more than 5 days of symp- to seasonal infl uenza vaccines be used as a mea- toms, and less than 1,000 white cells per cu.mm. sure of suppression of humoral immunity in in the CSF of which lymphocytes form the immunosuppressed patients, but this interesting majority [ 7 ] . approach has not been tested. 188 18 Neuroimmunological Diagnostic Tests 4.2 Cellular Immunity surface of lymphocytes activates them into DNA synthesis. These lectins are also sometimes 4.2.1 PPD referred to as mitogens. In the recent phase 2 In tuberculosis, a sensitive test for the presence study of the anti-CD25 monoclonal antibody, of the infection is demonstration of delayed-type daclizumab, in MS, a PHA stimulation test called hypersensitivity (DTH) to the bacteria by a skin ImmuKnow was performed to evaluate immune test, frequently called a purifi ed protein deriva- system functionality. This test, marketed by tive (PPD). Small amounts of mycobacterial anti- Cylex, utilizes stimulation ex vivo by PHA of gens are injected into the skin and within a few CD4-positive T cells in fresh whole blood, and hours after injection, T cells and other infl amma- ATP production is assessed. PHA stimulation tory cells enter the area leading to local swelling tests like the ImmuKnow may be used in the and redness which can be measured as a thick- future in neuroimmunological patients in whom ened red area on the forearm if the individual had excess immunosuppression may come with anti-mycobacterial immunity; this peak amount higher risks. of infl ammation is usually at about 2 days after injection. Individuals who did not have infection or exposure would not have swelling. A cause of References a false-negative reaction is anergy, the inability to react usually because of immunosuppression. 1. Gorelik L, Lerner M, Bixler S, et al. Anti-JC virus anti- Anergy can be ruled out by injecting with a panel bodies: implications for PML risk stratifi cation. Ann of antigens derived from minor infections to Neurol. 2010;68(3):295–303. 2. Bradl M, Misu T, Takahashi T, et al. Neuromyelitis which individuals are commonly exposed, such optica: pathogenicity of patient immunoglobulin as mumps, trichophyton, or candida; anergy is in vivo. Ann Neurol. 2009;66(5):630–43. ruled out when a positive test develops. Thus, in 3. Lennon VA, Wingerchuk DM, Kryzer TJ, et al. A serum most ill patients, a PPD should only be considered autoantibody marker of neuromyelitis optica: distinc- tion from multiple sclerosis. Lancet. 2004; negative if there is in addition a positive response 364(9451):2106–12. Dec 11–17. in one of the anergy controls. Increasingly, clini- 4. Dalmau J, Rosenfeld MR. Paraneoplastic syndromes of cians are using in vitro correlates of the PPD, the CNS. Lancet Neurol. 2008;7(4):327–40. such as the Quantiferon assay, in which lympho- 5. Reiber H. Cerebrospinal fl uid–physiology, analysis and interpretation of protein patterns for diagnosis of neu- cytes from the blood are exposed to Mycobacterial rological diseases. Mult Scler. 1998;4(3):99–107. antigens which produce activation of the lym- 6. Freedman MS, Thompson EJ, Deisenhammer F, et al. phocytes in TB patients. Recommended standard of cerebrospinal fl uid analysis in the diagnosis of multiple sclerosis: a consensus state- 4.2.2 PHA stimulation tests ment. Arch Neurol. 2005;62(6):865–70. The functional capacity of human lymphocytes 7. Thwaites GE, Schoeman JF. Update on tuberculosis of the central nervous system: pathogenesis, diagnosis, to rapidly divide upon stimulation can be tested and treatment. Clin Chest Med. 2009;30(4):745–54. ix. by adding lectins to the cells and measuring their 8. Hauser SL, Waubant E, Arnold DL, et al. B-cell deple- proliferation. Lectins are proteins that bind sugar tion with rituximab in relapsing-remitting multiple molecules with high affi nity; the binding of a sclerosis. N Engl J Med. 2008;358(7):676–88. 9. Pachner AR, Li L, Lagunoff D. Plasma cells in the lectin, such as phytohemagglutin (PHA) or central nervous system in the Theiler’s virus model of concanavalin A(conA) to sugar molecules on the multiple sclerosis. J Neuroimmunol. 2011;232:35–40. Therapy in Neuroimmunological Disease 19 We practice neurology in a fog…We’re ignorant. We’re making decisions based on what our sense of best practice medicine should be, but we have no solid knowledge that that’s actually the right thing

. S. Claiborne Johnston, M.D., Ph.D., executive vice editor of the Annals of Neurology, from Neurology Reviews, June 2010 1 Introduction nocere , i.e., the fi rst rule is to do no harm, but the trend over time has been to be more aggressive The sentiments of Dr. Johnston’s quotation about and less conservative. Increasingly, neurologists the clinical practice of neurology also apply to and statisticians have worked together to attempt the more limited fi eld of neuroimmunological to defi ne concepts such as “number needed to therapies. Most of the situations in which neu- treat” (NNT) and “number needed to harm” roimmunologists prescribe immune suppressive (NNH) so that clinicians could have a better idea therapies have not been subjected to randomized about risk/benefi t ratios for drugs. Unfortunately, clinical trials (RCTs) (see Chap. 7 ) so such treat- these types of analyses often provide information ment is frequently on shaky evidentiary grounds that is not highly supportive of drug use, and thus for justifi cation of its use. At times, when RCTs pharmaceutical companies are frequently loathe have been performed, the results have demon- to do such analyses of their products in pharma- strated that practices fi rmly entrenched in clinical ceutically company-sponsored clinical trials. practice have no merit. For instance, in the Optic Most of the medications used by neuroimmu- Neuritis Treatment Trial, described in Chap. 7 , nologists are meant to decrease infl ammation or the common practice of administering oral corti- suppress immune responses. These medications costeroids for optic neuritis was shown to be not are frequently called either immunosuppressive or helpful in that the rate of new episodes of optic immunomodulatory drugs; sometimes, the former neuritis in either eye was as high or higher in term is used if the drug increases the risk of infec- those receiving oral corticosteroids than in those tion or cancer, while the latter is used if it does not receiving intravenous corticosteroids or placebo have those unwanted effects. Both the power and [1 ] . In many instances, neuroimmunologists will adverse effects of most of these drugs are dose- try to adhere to the physician’s law, p rimum non dependent, with higher doses having more effect A.R. Pachner, A Primer of Neuroimmunological Disease, 189 DOI 10.1007/978-1-4614-2188-7_19, © Springer Science+Business Media, LLC 2012 190 19 Therapy in Neuroimmunological Disease and also more likelihood of side effects. Thus, the terms immunosuppression and immunomodulation 2 Chemicals are often used interchangeably. Most of the drugs used have broad-spectrum effects on the immune 2.1 Corticosteroids system, while recently more specifi cally targeted Corticosteroids are by far the most widely used drugs have been developed, primarily using mono- immunomodulatory drugs in the management of clonal antibody technology. neuroimmunological disease. They are effective N euroimmunologists using these drugs must in a wide variety of neuroimmunological dis- monitor patients for both their effi cacy and their eases, including multiple sclerosis, myasthenia side effects. Monitoring for effi cacy is usually gravis, chronic infl ammatory demyelinating done by analyzing the clinical effects of the drugs polyneuritis, and infl ammatory muscle disease; on the disease being treated, rather than the degree they are also used in suppressing infl ammation of effect on the immune system. Ideally, we could in infections such as tuberculous meningitis. also monitor the effects of these drugs on the They are a group of chemically related molecules immune system, but there is an unfortunate lack that resemble cholesterol in structure, and endog- of reliable measures of effect of these drugs on the enous versions are produced in the adrenal cor- immune system, i.e., no reliable biomarkers. This tex. They are usually taken by mouth, but is a major problem in the fi eld, since there is a intravenous preparations are available when broad range of response seen in individual patients, higher doses or more rapid effects are needed. and one is never sure that an adequate degree of They are thought to function through effects on immunosuppression is being reached. It is espe- gene expression by directly affecting transcrip- cially a problem if the disease is not responding tion factors within the nucleus, one of the most well to the treatment. In such situations, the neu- prominent of which is nuclear factor-kappa B roimmunologist does not know whether the ill- (NF-kappa B) (Inset 19.1 ). ness is simply severe and thus refractory to a normal level of immunosuppression, or alterna- tively, if the patient is not adequately immunosup- pressed. Different neuroimmunologists have their own ways of dealing with this conundrum. Many Inset 19.1 Nuclear Factor Kappa-Light-Chain- simply raise the dose of the medication to the Enhancer of Activated B Cells (NF-Kappa B) point of toxicity; others stop the ineffective drug NF-kappa B is a complex of proteins which, and try others. upon activation, can act relatively quickly in With respect to side effects of medications, the nucleus to upregulate expression of a neuroimmunologists differ in their philosophy. variety of genes involved in proliferation and Some are very conservative, adhering to the cell survival. In the absence of activation Hippocratic dictum “primum non nocere” (the stimuli, NF-kappa B components remain in fi rst rule is to do no harm), and reserving poten- the cytoplasm because of their interaction tially dangerous therapies for only the most with inhibitors of NF-kappa B (I-kappa Bs). severely involved patients. Others are more NF-kappa B is considered a rapidly acting aggressive attempting to eradicate even the last transcription factor. A prominent class of vestiges of an illness, accepting an occasional molecules which participate in its activation severe adverse outcome as an acceptable risk. is toll-like receptors (TLRs). Corticosteroids Most neuroimmunologists function between function in part by interferring with NF-kappa these two extremes. B, while pathogens upregulate NF-kappa B, I n this chapter, neuroimmunological thera- frequently through TLRs. There is evidence, pies used in MS and other neuroimmunological for instance, that B orrelia burgdorferi , the diseases are reviewed; more information on causative agent of Lyme neuroborreliosis therapies used primarily in MS can be found in upregulates NF-kappa B via TLR2. Chap. 7 . 2 Chemicals 191 2.1.1 Mechanism The effects of pharmacologic corticosteroids can Inset 19.2 A College Student on Corticos- be divided into those which have primarily a met- teroids with Malaise and Fatigue abolic action (mineralocorticoids) and those with J.L. was a 24-year-old graduate student predominantly immune and infl ammatory- who was admitted to the hospital after a fall related mechanisms of action (adrenocorticoids). because of bilateral leg weakness. She had Commercially available steroid therapies are usu- systemic lupus erythematosus (SLE), an ally some mix of these two characteristics of infl ammatory systemic disease affecting these two actions. They cause decreased numbers multiple organs, but had been doing very of lymphocytes in the peripheral blood, but well until 4 months prior to her admission increased numbers of neutrophils. Cytokine when she had a worsening which required secretion by T cells is decreased and B-cell func- moderate daily corticosteroid therapy. Her tion is impaired, particularly development of internist had considered lowering her dose antibody to new antigens. Many components of a month previous to her hospitalization, but the innate immune response are also impaired. had decided not to. She had returned to her internist 1 week prior to hospitalization 2.1.2 Side Effects with complaints of “not feeling well” and Side effects of short-term steroid dose are dose- “tired throughout the day,” but examina- related, and if low doses are used, adverse effects tion of the patient and routine blood work are minimal. Short-term, high dose use can cause had been unchanged from previous evalua- problems, including elevated blood glucose, tions. On the day of her hospitalization, she especially in patients at risk for, or already diag- had felt worse, and when walking away nosed with diabetes, acneiform skin disease, as from the table at dinner had fallen and had well as changes in mood, personality, and prob- trouble getting up. She called an ambulance lems with sleep. and was brought to the ER. By the time, Long-term steroid use is limited by a much she had received routine evaluation and longer list of potential serious side effects. Along blood work, it was late at night. The blood with chronicity of the above problems, the most work showed only a slightly higher neutro- serious problems include, but are not limited to: phil count than her normal which always – Bone problems including avascular necrosis, was elevated when she was treated with osteoporosis with fractures. corticosteroids. She continued to have – Body fl uid problems, including edema, weight trouble walking in the ER because of bilat- gain, and sodium retention. eral leg weakness. The neurologist was – Connective tissue disorders, including concerned about the bilateral leg weakness impaired wound healing, thinning, and easily but could fi nd no other worrisome signs cut skin. and thought that this might be steroid- – Muscle weakness because of damage to mus- induced muscle weakness. He ordered an cle cells. MRI of the cervical and thoracic spine, but – O phthalmologic problems, including cataracts. more severe cases were ahead of her and – Infl ammation of the pancreas. because of the lateness of the hour, the – Masking of the signs of infection; this problem patient was admitted to the neurology ward, is especially serious because sometimes infec- with imaging scheduled for the next day. tions can be life-threatening but elicit minimal However, the evening of admission, she signs because of the potent anti-infl ammatory began to develop severe back pain, a fever, actions of corticosteroids (see Inset 1 9.2 ). and worsening leg weakness, and quickly – Sleep disorders. progressed to confusion and hypotension. – Psychiatric side effects mostly agitation and Blood cultures were obtained, antibiotics anxiety. (continued) 192 19 Therapy in Neuroimmunological Disease (a) Monitoring for optimal benefi t: Corticosteroids Inset 19.2 (continued) predictably increase the peripheral white cell were begun, and emergency imaging of her count in most patients, which frequently spine showed a large epidural abscess. She causes consternation about elevated white cell rapidly deteriorated; emergency surgical counts, since raised white cells in the blood is consult was called, but she was considered often a harbinger of underlying infection, and too precarious to undergo anesthesia, and infections are more common in corticoster- she died of sepsis in the morning. Blood oid-treated individuals. However, raised white cultures grew S taphylococcus aureus . counts are not indicators of optimal treatment effect, since good outcomes can be achieved Author’s note . Spinal epidural abscess is when white counts are normal, and inadequate almost never an easy diagnosis to make but responses can be seen with high white counts. usually back pain, slowly progressive There are no good biomarkers of corticoster- weakness, and an abnormal white count oid effect, so neuroimmunologists will care- over a number of days leads to the correct fully assess how well the corticosteroids are diagnosis. In this patient, the corticosteroid downregulating the infl ammatory and immune therapy blunted the symptoms of back pain aspects of the disease process and adjust ste- and the development of the weakness; the roid doses accordingly. white count was not clearly abnormal (b) Monitoring for adverse effects: All of the because corticosteroids normally elevate above potential side effects of chronic corti- the neutrophil count. This patient’s story costeroid therapy need to be monitored. demonstrates masking of symptoms of Patients with diabetes mellitus must be very infection, one of the many dangerous side carefully watched using assessments of blood effects of chronic corticosteroid use. sugar and hemoglobin A1c, a glycosylated hemoglobin which increases with poor con- trol of diabetes over time. Even patients with- B ecause of the extensive potential side effects out diabetes can become hyperglycemic, of long-term therapy, the benefi t/risk ratio for using sometimes dangerously so, when they are these drugs must constantly be addressed during treated with corticosteroids, especially if there therapy. This assessment is made even more diffi - is diabetes in the family. Psychiatric problems cult by the unpredictability of many of these side such as depression or mania are common and effects. These side effects are also to some degree can require medication for control. Bone dose-related so that the clinician must always density measurements at baseline and at attempt to use the minimum dose possible. intervals during treatment

are useful. Body These side effects of corticosteroids are most weight needs to be monitored as excessive likely with higher doses and more prolonged salt and water retention sometimes can therapy. Thus, most of the time corticosteroids require diuretic therapy. are administered for relatively short periods, a few days to at most a few weeks, and then tapered down to discontinuation or to alternate day ther- 2.2 Immunosuppressives apy. Alternatively, especially if there is no emer- gent need to induce a remission quickly, alternate 2.2.1 Azathioprine (Imuran in the USA) day steroids can be initiated at low doses with A small chemical (molecular weight of 277), aza- subsequent increase in dose as needed [2 ] . thioprine is one of the original immunosuppres- sive medications, fi rst used in the 1960s in organ 2.1.3 Monitoring transplantation and in MS not long thereafter. It Careful monitoring for both optimal benefi t and is still used extensively in transplantation, minimum adverse side effects is necessary, espe- although it is being replaced to some extent by cially for long-term use. mycophenolate (see below). It is a purine analog 2 Chemicals 193 Fig. 19.1 Thiopurine drug metabolism. The fi gure is a representation of thiopu- rine drug biotransforma- tion, with azathioprine being converted in vivo to 6-mercaptopurine (6-MP), followed by the metabolic activation of 6-MP to form 6-thioguanine nucleotides. 6-MP undergoes metabo- lism catalyzed by xanthine oxidase (XO) or TPMT and a DNA synthesis inhibitor and is metabolized immunosuppress for transplant rejection, discon- to 6-mercaptopurine and 6-thioguanine and 2 tinuation is not recommended when the patient inactive metabolites (see Fig. 19.1 ). Thus, rapidly becomes pregnant. For all of these reasons, aza- dividing cells, such as lymphocytes during an thioprine’s relative popularity is due to its gener- active immune response, are inhibited. ally being considered the safest and easiest of the Administered as a once or twice daily oral dose, immunosuppressives. it is very popular for MS in Europe, listed as a “basic” drug for MS, along with IFN-b and GA, 2.2.2 Methotrexate by the Multiple Sclerosis Therapy Consensus Methotrexate acts on rapidly dividing cells by Group in 2008, consisting of 109 European MS being a folic acid antagonist, resulting in experts [3 ] . A recent study in Italy demonstrated decreased nucleotide synthesis. It is one of the that azathioprine was very effective in decreasing oldest immunosupressives currently used, hav- gadolinium-enhancing lesions in MS [4 ] . It is ing been developed, initially as a cancer chemo- used much less frequently for MS in the USA, therapeutic agent, by Yellapragada Subbarao at relative to Europe. Lederle Laboratories in the late 1940s. The most Another use of azathioprine in neuroimmuno- common use in the USA is in cancer chemother- logical diseases is as a “steroid-sparing” agent. apy and, at much lower doses, rheumatoid arthri- Since chronic high-dose corticosteroid therapy tis (RA). For most indications, methotrexate can may have a high incidence of unacceptable side be administered as a once weekly oral dose. In effects, patients who require prolonged therapy, RA, it is the most popular of the immunosup- such as those with infl ammatory neuropathies, pressives for the following reasons: it is effec- myopathies, or myasthenia gravis, will frequently tive, patients are adherent with the medication, be treated with azathioprine in conjunction with other agents can be added to it, side effects are lowering the dose of corticosteroids, ideally to uncommon, and those side effects which do the point of using alternate-day corticosteroids. occur (hepatitis or bone marrow suppression) The most severe potential risks of azathioprine can be easily monitored with routine blood tests. are carcinogenesis and teratogenesis, although It is only rarely used in MS by American neu- the incidence of both of these seems to be rologists, and, within neuroimmunological thera- extremely low in MS patients when other immu- peutics, is more commonly given as a second-line nosuppressives are not used concurrently. The or steroid-sparing agent for the infl ammatory risk of teratogenesis is so low that, when used to myopathies. 194 19 Therapy in Neuroimmunological Disease cytokine release, primarily IL-2 by T cells. This happens via the binding of cyclosporin to cyclo- philin and subsequent inhibition of the phos- phatase calcineurin, an important molecule in IL-2 transcription. Related drugs, used primar- ily for organ transplantation and not in neuroim- munology, are sirolimus (rapamycin) and tacrolimus (FK506). Sometimes, these drugs, cyclosporin, rapamycin, and tacrolimus, are grouped together and referred to as calcineurin inhibitors (CNIs). Cyclosporine and the other CNIs have been extensively used in transplanta- tion, and their introduction in that fi eld has greatly cut down the rate of transplant rejec- tions. However, CNIs can have similar side effects to those associated with corticosteroids and thus the use of CNIs with corticosteroids, with the attendant potential for cumulative adverse effects, needs to be especially closely Fig. 19.2 Cyclosporine, with its distinctive cyclical structure, was isolated by growth of the fungus, monitored. Tolypocladium infl atum , from a soil sample in Norway in 1969, by Sandoz (now Novartis) scientists. Its structure is 2.2.5 Cyclophosphamide (Cytoxan) a cyclic peptide containing 11 amino acids. The drug was This drug is a small molecule (MW = 261) related initially developed for its effect in the prevention of trans- plant rejection. Some of the fi rst studies were in liver to the nitrogen mustards developed for chemical transplantation warfare and is a nonspecifi c DNA alkylating agent. It suppresses cell replication and thus both cell-mediated and humoral immunity. It has been 2.2.3 Mycophenolate (CellCept used for at least 50 years as a chemotherapeutic or Myfortic) agent in a variety of malignancies but mostly for This relatively new compound, a purine synthesis lymphomas. In contrast to azathioprine, cyclo- inhibitor derived from the fungus Penicillium, phosphamide is considered a stronger immuno- has been extensively used in the transplant popu- suppressive agent and is generally felt to be more lation, including kidney transplantation, and has effective than less potent immunosuppressives in been increasingly tried in neuroimmunological suppressing infl ammation in patients with very diseases, such as MS and NMO [5 ] . Its use has active infl ammatory disease. However, the fl ip lessened somewhat with reports of PML (see side of that coin is that adverse effects of cyclo- Chap. 12 ) in patients taking the drug, usually in phosphamide are also more likely (see Inset 1 9.3 ). transplant patients. Its immunosuppressive effects are dose- dependent, and at low doses, cyclophosphamide can be 2.2.4 Cyclosporine immunostimulatory, possibly because of prefer- This drug is produced by the fungus ential effect of low doses on regulatory T cells Tolypocladium infl atum (see Fig. 1 9.2 ). One of (see T cells in Chap. 1 ). Some MS specialists reg its unique features is that it contains a d -amino use cyclophosphamide relatively frequently, fi nd- acid, rarely encountered in nature, in contrast to ing it a helpful adjunct in patients not responding the l optical isomeric form of amino acids nor- to safer medications [6 ] , but most neurologists mally found in proteins. The mechanism of use cyclophosphamide for neuroimmunological action of cyclosporine is the inhibition of diseases only rarely. 2 Chemicals 195 Fig. 19.3 Fingolimod’s structure resembles that of sphingosine, a naturally occurring glycolipid which is an important molecule for lymphocyte traffi cking through lymph nodes Inset 19.3 Fever and Confusion in an MS Urinary tract infections are more likely in Patient Treated with Cyclophosphamide MS patients to start with, and the combina- A 31-year-old woman, mother of four chil- tion of MS and cyclophosphamide therapy dren, was seen for the fi rst time in raises the risk of urine infections to a very MS clinic and emergently admitted to high level. This patient nearly died of uro- University Hospital for cyclophosphamide sepsis, but fortunately recovered. treatment. She had been diagnosed with MS approximately 1 year previously and had had three serious attacks, each with residual disability, and had not responded to inter- 2.2.6 New Drugs feron-b (IFN-b ). On IFN-b 44 m g subcuta- Fingolimod neously three times per week, she had This medication, whose brand name is Gilenya, multiple gadolinium-enhancing lesions. On is unique for a number of reasons. First, its struc- admission, a urine analysis and urine culture ture is that of a sphingolipid (Fig. 1 9.3 ), indicat- were negative. She tolerated well the fi rst ing that is belongs to a large group of three doses of cyclophosphamide therapy neurologically important, but poorly understood [1 6 ] , but then developed fever and confu- molecules, which include glycosphingolipids, sion. Broad-spectrum antibiotics were initi- such as gangliosides and cerebrosides. Second, it ated but the patient developed confusion and is the fi rst of a class of drugs which focus on hypotension and was admitted to the inten- interactions between sphingolipids and their sive care unit. She became lethargic, poorly receptors. For fi ngolimod, the biologically rele- responsive, and her white blood cell count vant ligand and receptor are sphingosine and dropped to 500 (normal 5,000–10,000). sphingosine-1 phosphate (S-1 P) receptor, which Blood and urine cultures revealed the gram- is a critically important receptor on many classes negative bacterium P seudomonas aerugi- of lymphocytes, including T- and B cells, and nosa . After a few days, she began to improve, especially important in lymphocyte traffi cking was transferred back to the neurology ward, [ 7 ] . The drug functions by causing internalization and ultimately was discharged after a 2-week of S-1 P receptors leading to interference with hospitalization. Cyclophosphamide that had normal ligand–receptor function. Fingolimod’s been discontinued when she became urosep- effect of decreasing attacks in MS without induc- tic was not reinitiated, but the patient’s MS ing major immunosuppression with coincident went into remission for 2 years on IFN- b opportunistic infections is thought to be due to its alone. She was begun on natalizumab when preferential retention of subpopulations in lymph it became available in 2004. nodes while affecting other subpopulations less Author’s note . Cyclophosphamide is a [ 8 ] . Specifi cally, it is thought to retain naïve potent immunosuppressive agent, which T cells and central memory T cells in lymph increases the risk of serious infections. nodes while having less of an effect on peripheral effector memory T cells; it is the peripheral 196 19 Therapy in Neuroimmunological Disease effector memory T cells which are thought to be blood obtained from at least 1,000 donors. IVIg most important during acute infections. The was originally developed to treat children with retention of lymphocytes in the lymph nodes Bruton’s type agammaglobulinemia (see Chap. 1 ), leads to substantial lymphopenia in the periph- a congenital condition due to a mutation in an eral blood, with total lymphocyte counts in treated enzyme, and other genetic conditions causing low patients generally being 20–30% of pretreatment serum immunoglobulin levels (hypogammaglobu- values. This is an expected effect of the drug, and linemias). IVIg was subsequently found to have indeed can serve as a useful biomarker of compli- immunomodulatory effects, and now is used to ance. Fingolimod also accumulates in the CNS treat a broad range of immune-mediated condi- [9 ] , and neuroprotective effects are possible and tions. Its mechanism of action is unknown and hoped-for but not proven. Fingolimod was may be due to a suppression of complement activ- approved for the treatment of MS in September ity, downregulation of autoantibody production, 2010, and since its approval and has been increas- blockade of Fc receptors, or downregulation of ingly used as the fi rst oral MS disease-modifying infl ammatory cytokine production. Its most drug. It is the fi rst sphingosine agonist to be used appealing characteristic is safety, i.e., IVIg therapy for the treatment of disease. does not result in increased susceptibility to infec- tion or to increased risk of malignancy, and there Cladribine are no other major systemic adverse effects such This medication is FDA approved for the treatment as kidney or liver injury. The main disadvantage is of hairy cell leukemia and is approved in other its cost, which, for chronic conditions, is often countries for the treatment of chronic lymphocytic more than $50,000 USD per year. leukemia. The mechanism of action is via disrup- IVIg can be considered effective in Guillain– tion of cellular metabolism by an active metabolite

Barré syndrome, chronic infl ammatory demyeli- of cladribine, 2-chlorodeoxyadenosine triphos- nating polyneuropathy and multifocal motor phate. Lymphocytes are preferentially affected. neuropathy, but its effi cacy in other conditions is Cladribine treatment results in sustained reductions less well-documented. Some investigators feel it of both CD4 and CD8 counts. Immunosuppression is a second-line agent for dermatomyositis and is the result of therapy, although opportunistic stiff-person syndrome. Despite lack of hard evi- infections have not been a prominent feature of dence for positive effect in most situations, it has clinical trials of cladribine in MS. After a promis- been increasingly used in a variety of other neu- ing start and high hopes for approval for MS in the rological diseases, prompting concerns related to European Union and the USA, the drug was not the increasing cost and lack of demonstrated effi - approved by either, and the drug faces an uncertain cacy [1 0 ] . For instance, it continues to be used in future in MS globally. multiple sclerosis, despite the results of a recent large multi-center, randomized, double-blind, placebo-controlled study [1 1 ] , which demon- 3 Biologics: Large Molecules strated no effi cacy relative to placebo for the use Produced via Recombinant of 0.2 or 0.4 g/kg every 4 weeks for 1 year. Technology or from Human Specimens 3.2 Cytokines 3.1 Intravenous Immunoglobulin At this point in time, the only recombinant form Intravenous immunoglobulin (IVIg) is used exten- of a cytokine being used in neuroimmunological sively in neuroimmunological disease, and con- therapy is IFN-b . This molecule is the most sists of human IgG purifi ed from pooled blood commonly prescribed disease-modifying ther- from normal humans. The FDA requires that, prior apy for MS; its use in that disease is described in to use in the USA, a given batch be an aggregate of Chap. 7 . 4 Procedures 197 3.3 Monoclonal Antibodies (d) Monoclonal antibody to CD25 (daclizumab, (See Sect. 2.1 in Chap. 17 ) Zenapax): CD25 is the a -subunit of the IL-2 receptor present on activated T cells, some Natalizumab was the fi rst monoclonal antibody B cells, and miscellaneous other cells. approved for a neurological disease when it was Daclizumab is currently FDA-approved for approved by the FDA in 2005 for the treatment of the treatment of transplant rejection. The MS. Three other monoclonals, already approved mechanism of action of the drug is unknown, by the FDA for the treatment of cancer or trans- but thought possibly due to be a drug- plant rejection have had promising phase 2 studies induced expansion of a regulatory subset of in MS and are being evaluated in phase 3 studies. natural killer (NK) cells, those that are posi- (a) Monoclonal antibody to a -4 integrin (natali- tive for the surface marker CD56. In a large zumab, Tysabri): This biologic, reviewed in multicenter phase 2 study of IFN-b plus Chap. 7 , is currently being prescribed for tens daclizumab versus IFN-b alone, MS patients of thousands of patients worldwide. on both drugs had substantially fewer MRI (b) Monoclonal antibodies to CD20 (rituximab lesions [1 4 ] . or ocrelizumab): These biologics deplete cells in the B-lymphocyte lineage by binding to the CD20 antigen on their surface and is 4 Procedures discussed in Chap. 17 . Rituximab is not FDA- approved for use in any neuroimmunological 4.1 Plasmapheresis disease, including MS, but has been used for lymphoma since its approval for that cancer in This procedure, also called plasma exchange, is 1997. Phase 3 trials in MS are now under way sometimes referred to simplistically as “washing to determine effi cacy, after demonstration of the blood.” It consists of the separation of plasma substantial effi cacy in a phase 2 study [1 2 ] . from cellular constituents of the blood and its (c) Monoclonal antibody to CD52 (alemtuzumab, replacement with a substitution fl uid. In neu- Campath): CD52 is a surface antigen on a roimmunology, the procedure is used when the large percentage of non-neutrophil white putative cause of the disorder is the presence of blood cells, and administration of this mono- autoantibodies, whose concentration can be less- clonal results in profound and prolonged ened by removing the plasma, and replacing the depletion of lymphocytes and monocytes. plasma with fl uids which do not contain immu- This drug is already available to physicians as noglobulins. Although plasmapheresis does an FDA-approved agent for the treatment of indeed lower the concentration of immunoglob- B-cell chronic lymphocytic leukemia. In a ulins in the blood, it also lowers the concentra- phase 2, comparator study of Campath versus tion of all blood proteins indiscriminately. There IFN-b in patients with MS, Campath was is no convincing proof that its effect on autoanti- more effective in the treatment of both clini- body concentrations is the mechanism of action cal and MRI measures of disease [1 3 ] . Use of of benefi t for any of the diseases for which it is this agent may be limited by its serious used, except for possibly myasthenia gravis. It adverse effects, including a high rate of auto- has been used extensively in Guillain–Barré syn- immune thyroid disorders (for example, drome and myasthenic crisis. It has also been hyperthyroidism or Grave’s Disease) and used less widely for chronic infl ammatory their complications, immune-mediated throm- demyelinating polyneuropathy, paraproteinemic bocytopenia (resulting in a very low level of p olyneuropathy, stiff person syndrome, and para- platelets) leading to a high risk of bleeding, as neoplastic syndromes. The use of plasmaphere- well as a Goodpasture’s syndrome, an auto- sis in neurological disorders has recently been immune syndrome causing damage to the reviewed [1 5 ] . It is used in similar situations as kidneys and lungs. IVIg (see above). 198 19 Therapy in Neuroimmunological Disease 4.2 Thymectomy 7. Spiegel S, Milstien S. The outs and the ins of sphin- gosine-1-phosphate in immunity. Nat Rev Immunol. 2011;11(6):403–15. This procedure, surgical removal of the thymus 8. Mehling M, Brinkmann V, Antel J, et al. FTY720 in the therapy of myasthenia gravis, is described therapy exerts differential effects on T cell subsets in in Chap. 10 . multiple sclerosis. Neurology. 2008;71(16):1261–7. 9. Li L, Matsumoto M, Seabrook T, Cojean C, Brinkmann V, Pachner AR. The effect of FTY720 in the Theiler’s virus model of multiple sclerosis. J Neurol Sci. References 2011;308:41–8. 10. Elovaara I, Hietaharju A. Can we face the challenge of expanding use of intravenous immunoglobulin in neu- 1. Beck RW, Cleary PA, Anderson Jr MM, et al. A ran- rology? Acta Neurol Scand. 2010;122:309–15. domized, controlled trial of corticosteroids in the 11. Fazekas F, Lublin FD, Li D, et al. Intravenous immu- treatment of acute optic neuritis. The Optic Neuritis noglobulin in relapsing-remitting multiple sclerosis: a Study Group. N Engl J Med. 1992;326(9):581–8. dose-fi nding trial. Neurology. 2008;71(4):265–71. 2. Sathasivam S. Steroids and immunosuppressant drugs 12. Hauser SL, Waubant E, Arnold DL, et al. B-cell deple- in myasthenia gravis. Nat Clin Pract Neurol. tion with rituximab in relapsing-remitting multiple 2008;4(6):317–27. sclerosis. N Engl J Med. 2008;358(7):676–88. 3. Wiendl H, Toyka KV, Rieckmann P, Gold R, Hartung 13. Coles AJ, Compston DA, Selmaj KW, et al. HP, Hohlfeld R. Basic and escalating immuno- Alemtuzumab vs. interferon beta-1a in early multiple modulatory treatments in multiple sclerosis: current sclerosis. N Engl J Med. 2008;359(17):1786–801. therapeutic recommendations. J Neurol. 2008;255(10): 14. Wynn D, Kaufman M, Montalban X, et al. Daclizumab 1449–63. in active relapsing multiple sclerosis (CHOICE study): 4. Massacesi L, Parigi A, Barilaro A, et al. Effi cacy of a phase 2, randomised, double-blind, placebo-con- azathioprine on multiple sclerosis new brain lesions trolled, add-on trial with interferon beta. Lancet evaluated using magnetic resonance imaging. Arch Neurol. 2010;9(4):381–90. Neurol. 2005;62(12):1843–7. 15. Schroder A, Linker RA, Gold R. Plasmapheresis for 5. Jacob A, Matiello M, Weinshenker BG, et al. neurological disorders. Expert Rev Neurother. 2009; Treatment of neuromyelitis optica with mycopheno- 9(9):1331–9. late mofetil: retrospective analysis of 24 patients. 16. Weiner HL, Mackin GA, Orav EJ, et al. Intermittent Arch Neurol. 2009;66(9):1128–33. cyclophosphamide pulse therapy in progressive mul- 6. Elkhalifa A, Weiner H. Cyclophosphamide treatment tiple sclerosis: fi nal report of the Northeast Cooperative of MS: current therapeutic approaches and treatment Multiple Sclerosis Treatment Group. Neurology. regimens. Int MS J. 2010;17(1):12–8. 1993;43(5):910–8. Index A Amphotericin B , 124 Abscesses , 62, 116, 125, 129 AMPPE. See Acute multifocal placoid pigment Acetylcholine , 16, 19, 80, 103, 156 epitheliopathy (AMPPE) Acetylcholine receptor (AChR) , 12, 19, 26, 34, 103, AMSAN. See Acute motor and sensory axonal 104, 106, 108–111, 172, 181–182 neuropathy (AMSAN) Acetylcholinesterase , 103, 104 Amyloid precursor protein (APP) , 155 Acetylcholinesterase inhibitors , 104, 107 Amyotrophic lateral sclerosis (ALS) , 20, 24, 132, 155 AChR. See Acetylcholine receptor (AChR) AN-1792 , 156 Aciclovir , 127, 128, 136, 161 ANA. See Antinuclear antibodies (ANA) Acquired neuromyotonia (NMT) , 162 ANCA , 144 Active comparator-controlled , 70 Anti-aquaporin 4, 27, 52, 170, 181, 182 Acute disseminated encephalomyelitis (ADEM) , Antibody-dependent cellular cytotoxicity (ADCC) , 26, 31, 58, 63, 84 8, 172 Acute infl ammatory demyelinating polyneuropathy Anticardiolipin antibodies , 138, 142 (AIDP) , 24, 93, 96–98 Anti-ganglioside antibodies , 97 Acute motor and sensory axonal neuropathy Antigen-presenting cell (APC) , 4, 5, 10, 29, 33, 87 (AMSAN) , 96 Antigen receptors , 3, 30 Acute motor axonal neuropathy (AMAN) , 95–97 Anti-GQ1b antibodies , 95, 97 Acute multifocal placoid pigment epitheliopathy Anti-Hu antibodies , 182 (AMPPE) , 164 Anti-Jo-1 antibodies , 113 AD. See Alzheimer’s disease (AD) Anti-myeloperoxidase (MPO) , 144, 148 Adalimumab , 11, 170 Anti-neutrophilic cytoplasmic antibodies , 144 ADCC. See Antibody-dependent cellular cytotoxicity Anti-NMDA receptor encephalitis , 149, 151 (ADCC) Antinuclear antibodies (ANA) , 145, 180 ADEM. See Acute disseminated encephalomyelitis Antiphospholipid antibody syndrome (APS) , 58, 138, (ADEM) 142–143, 145, 180 Adhesion molecules , 3, 13, 32, 76, 89, 99, 100, 130, Anti-Purkinje cell , 35, 148 157, 169 Anti-Yo antibodies , 149, 182 Affi nity constant , 181, 184 APC. S ee Antigen-presenting cell (APC) AIDP. See Acute infl ammatory demyelinating Aphasia , 18, 130 polyneuropathy (AIDP) Apoptose , 85 Alemtuzumab , 35, 168, 171, 197 Apoptosis , 3, 7, 100, 168 Alpha 4-integrin (natalizumab, Tysabri) , 13 APP. See Amyloid precursor protein (APP) a -synuclein , 156 APS. S ee Antiphospholipid antibody syndrome (APS) ALS. See Amyotrophic lateral sclerosis (ALS) Aquaporin-4 receptors , 27, 34, 62 Alzheimer’s disease (AD) , 2, 23, 155–156, 173 antibody , 169–170, 172, 181, 182 Alzheimer’s vaccine , 156 in NMO , 180, 181 AMAN. See Acute motor axonal neuropathy (AMAN) Arachnoid mater , 20, 28 Aminoacyl-tRNA synthetases , 113 Arachnoid villi , 20 4-aminopyridine (Ampyra) , 79 Argyll Robertson pupils , 138 Amphiphysin , 162 Arthrogryposis multiplex congenital , 109 A.R. Pachner, A Primer of Neuroimmunological Disease, 199 DOI 10.1007/978-1-4614-2188-7, © Springer Science+Business Media, LLC 2012 200 Index ASCVD. See Atherosclerotic cerebrovascular disease Calcineurin inhibitors (CNIs) , 194 (ASCVD) Campath , 197 Aseptic meningitis , 123, 125 Campylobacter jejuni , 95 Astrocytes , 17–18, 27, 32, 33, 88, 156, 181 CAMs. See Cell adhesion molecules (CAMs) Astrocytic endfeet , 27, 28, 86 Candida , 7, 33, 188 Ataxia , 17, 22, 65, 97, 149, 152, 161, 184 Canine distemper virus (CDV) , 88, 89 Atherosclerotic cerebrovascular disease (ASCVD) , 155 Caprine arthritis encephalitis virus (CAEV) , 87, 89 Atherosclerotic plaque , 157 Carpal tunnel syndrome , 19 Atrophy , 23, 24, 39, 42, 46, 52, 53, 106, 111, 129, 152, Caspases , 3 155, 157, 184 CBC. See Complete blood count (CBC) Attack(s) , 33, 37, 40–46, 50–52, 55, 57, 59, 61, 63, 71, CD. See Cluster of differentiation (CD) molecules 72, 74, 83, 85, 89, 95, 100, 103, 122, 130, 195 CD3 antigen , 6, 8, 12, 13, 177 Axon , 16, 17, 20, 23, 24, 95, 96, 99, 103, 134 CD4 antigen , 6, 13, 87, 117, 124, 177, 196 Azathioprine (Imuran) , 76–78, 108, 128, 192–194 CD8 antigen , 6, 12, 13, 126, 177, 196 CD19 antigen , 5, 13, 177 CD20 antigen , 4, 5, 13, 35, 130, 168, 169, 177, 187, 197 B CD25 antigen , 197 Babinski , 22, 51, 52, 117 CD52 antigen , 169, 171, 197 Baclofen , 16, 79 CD56 antigen , 8, 197 Bannwarth’s syndrome , 122 CD59 antigen , 13 Bapineuzumab , 156 CD106 antigen

, 76 Barré, Jean Alexander , 93 CDMS. See Clinically defi nite MS (CDMS) BBB. See Blood–brain barrier (BBB) Cell adhesion molecules (CAMs) , 13, 76, 100 B cell. See Bursa-derived cell (B cell) Cell body , 16, 17, 27 B-1 cell , 5 Cerebellum , 15, 16, 18, 148, 149, 152 B-2 cell , 5 Cerebrospinal fl uid (CSF) , 20, 21, 30–32, 35, 54–55, B-cell receptor (BCR) , 3–5 57–61, 63, 89, 97, 117–125, 127, 128, 131, 138, Bcl-2 , 3 143, 146, 152, 160, 161, 163, 164, 170, 175, 177, BCR. See B-cell receptor (BCR) 180, 183–187 Behcet’s syndrome , 164 Cerebrum , 18, 153, 155 b -amyloid , 155, 156 Certolizumab , 11, 170 Beta-2 glycoprotein , 142 CFE. See Chronic focal encephalitis (CFE) BFP. See Biological false positive (BFP) CFS. See Chronic fatigue syndrome (CFS) Bickerstaff’s brainstem encephalitis , 97 Chancre , 137 Biological false positive (BFP) , 145, 180 Charcot , 22, 38, 53 Biologics , 74, 167, 169, 170, 196–197 Chemokines , 3, 8, 27, 30, 76, 100, 157 Blood–brain barrier (BBB) , 20, 27, 30, 32, 53, 54, 84, Chickenpox , 136, 161 87, 89, 90, 100, 115, 119, 171, 172, 177, 181, 183 Chinese hamster ovary (CHO) cells , 72, 169 Blood–nerve barrier (BNB) , 32, 100 CHO. See Chinese hamster ovary (CHO) cells Blown pupil , 127 Cholecystokinin , 79 BNB. See Blood–nerve barrier (BNB) Chorea , 161–162 Bordetella pertussis , 84 Chronic fatigue syndrome (CFS) , 179 Borrelia afzelii , 120 Chronic focal encephalitis (CFE) , 164 Borrelia burgdorferi , 2–4, 13, 50, 61, 119–121, 123, 175, Chronic infl ammatory demyelinating polyneuropathy 176, 178–180, 186, 190 (CIDP) , 24, 26, 98, 196, 197 Borrelia garinii , 120 Churg-Strauss syndrome , 144 Bradykinesia , 156 CIDP. S ee Chronic infl ammatory demyelinating polyneu- Brain abscess , 62, 116, 129 ropathy (CIDP) Brainstem , 18, 21, 54, 97, 138, 153, 164 CIS. See Clinically isolated syndrome (CIS) Bungarotoxin , 104, 172, 181–182 Class II MHC antigens , 8, 30, 39 Bursa-derived cell (B cell) , 3–8, 10, 13, 26, 28–31, 33, Clinically defi nite MS (CDMS) , 41, 57, 71 54, 77, 88, 98, 110, 130, 153, 168, 169, 172, 177, Clinically isolated syndrome (CIS) , 41, 43, 50, 51, 185, 187, 190, 191, 195, 197 53–55, 57, 71 Bursa of Fabricius , 4 Cluster of differentiation (CD) molecules , 3, 12–13, 177 CMAP. See Compound muscle action potential (CMAP) CMV. See Cytomegalovirus (CMV) C CNIs. See Calcineurin inhibitors (CNIs) Cadherins , 13 CNS toxoplasmosis , 7, 116, 117 CAEV. See Caprine arthritis encephalitis virus (CAEV) Cobratoxin , 104, 110 Calcineurin , 194 Complement , 3, 8, 10, 13, 97, 100, 103, 121, 156, 168, 196 Index 201 Complement system , 85, 156 Distal acquired demyelinating sensory neuropathy Complete blood count (CBC) , 31, 51, 177 (DADS) , 99 Compound muscle action potential (CMAP) , 107 Distemper viruses , 88, 160 Conjugate , 21, 40, 150, 178 DMDs. See Disease-modifying drugs (DMDs) Conotoxin , 104, 172, 182 DN. See Diphtheritic neuropathy (DN) Coonhound paralysis , 95 Dopamine , 16, 156 Copolymer , 75 Dopaminergic neurons , 156 Corticosteroids , 38, 51, 57, 65, 72, 78, 97, 98, 108, 112, Double-blinded , 70 113, 118, 136, 141, 144–146, 150, 152, 153, 163, dRVVT. See Dilute Russell’s viper venom time assay 164, 189–194 (dRVVT) Corynebacterium diphtheriae , 93 DTH. See Delayed-type hypersensitivity (DTH) Cranial nerves , 18, 20, 21, 30, 44, 63, 64, 93, 94, 97, DTRs. See Deep tendon refl exes (DTRs) 122, 124, 127, 141–143, 164 Dura mater , 20, 28 C-reactive protein (hs-CRP) , 158 Cryptic antigens , 100 Cryptococcal antigen , 180, 187 E Cryptococcal antigen test , 124 EAE. See Experimental autoimmune encephalomyelitis Cryptococcus neoformans , 124 (EAE) CSF. See Cerebrospinal fl uid (CSF) EAM. See Experimental autoimmune myositis (EAM) Cuprizone , 89 EAMG. See Experimental autoimmune myasthenia Cyclophilin , 194 gravis (EAMG) Cyclophosphamide (Cytoxan) , 76–78, 108, 143, 145, EAN. See Experimental autoimmune neuritis (EAN) 146, 194–195 EBV. See Epstein–Barr virus (EBV) Cyclosporine , 38, 194 Echinococcosis , 125 Cysticercosis , 51, 61, 113, 125, 129, 187 Echinococcus , 129 Cytokines , 3–6, 8, 11–13, 27, 29, 30, 32, 33, 76, 89, E.coli , 72, 122 100, 144, 156, 157, 196 EDSS. See Expanded disability status scale (EDSS) Cytomegalovirus (CMV) , 7, 13, 130, 179 EEG. See Electro-encephalography (EEG) Efalizumab , 130, 137 Electric eels , 109 D Electric organ , 109–110 Daclizumab , 8, 35, 168, 188, 197 Electro-encephalography (EEG) , 23–24, 160 DADS. See Distal acquired demyelinating sensory Electromyography (EMG) , 19, 23–24, 97, 98, 107–109, neuropathy (DADS) 112, 133, 134, 162, 163 Dancing eyes , 150 Electromyography and nerve conduction velocity testing , Dancing eyes–dancing feet , 150 24, 163 Dancing feet , 150 ELISA. See Enzyme-linked immunosorbent assay (ELISA) Dawson, James Walker , 53 Embolus , 157 Dawson’s fi ngers , 53 EMEA , 71 DCs. See Dendritic cells (DCs) EMG. See Electromyography (EMG) Deep tendon refl exes (DTRs) , 20–22, 44, 51, 95, 97, Encephalitis , 21, 26, 32, 88, 89, 97, 121, 125–127, 106, 108 130–132, 148–152, 159, 164, 172, 179, 182, 187 Delayed-type hypersensitivity (DTH) , 32, 33, 188 Encephalitogen(s) , 75, 84, 85, 100, 171 Dementia , 25, 33, 63, 65, 128, 149, 155, 157 Encephalopathy , 21, 63, 66, 133, 163–164 Dementia with Lewy bodies , 157 Endomysium , 111 Demyelination , 17, 31, 37, 41, 42, 46, 49, 62, 63, 65, 83, Enzyme-linked immunosorbent assay (ELISA) , 74, 135, 84, 86–89, 95–97, 100, 121, 126, 141, 159, 160, 142, 175, 177–180 170–172 EOMs. See Extraocular muscles (EOMs) Dendritic cells (DCs) , 3, 8, 9, 13, 28–30, 85, 111, Ependymal cells , 20 157, 171 Epinephrine , 16 Dendrotoxin , 104, 162, 172, 182 Epstein–Barr virus (EBV) , 7, 60, 179 Dermatomyositis , 111–114, 150, 152, 196 Epstein–Barr virus-associated lymphoma , 7 Devic’s disease , 62, 170 Erythema migrans , 122 Dilute Russell’s viper venom time assay (dRVVT) , Erythrocyte sedimentation rate (ESR) , 31, 113, 144, 177 142, 143 ESR. See Erythrocyte sedimentation rate (ESR) Diphtheria antitoxin , 94 Etanercept , 11, 169, 170 Diphtheria toxin , 94 Exotoxin , 84 Diphtheritic neuropathy (DN) , 93, 94 Expanded disability status scale (EDSS) , 22, 40–42, 45, 46 Diplopia , 21, 50, 106 Experimental autoimmune encephalomyelitis (EAE) , 26, Disease-modifying drugs (DMDs) , 54, 69–78, 196 27, 31, 39, 75, 84–90, 100, 170, 171, 181 202 Index Experimental autoimmune myasthenia gravis (EAMG) , Glycolipids , 95, 99, 100, 195 26, 27, 109, 110 Glycosylated , 72, 192 Experimental autoimmune myositis (EAM) , 114 GM1 , 95 Experimental autoimmune neuritis (EAN) , 26, 27, 93, 100 Gottron’s papules , 112 Extraocular muscles (EOMs) , 105 GPCR. See G protein-coupled receptors (GPCR) GPI. See General paresis of the insane (GPI) G protein-coupled receptors (GPCR) , 171 F G1Qb , 100 Fab portion , 4, 9, 10, 99, 168 Gram stain , 122–124, 187 FACS. See Fluorescence-activated cell sorting (FACS) Granular layer , 148 Famciclovir (Famvir) , 136 Granuloma , 63, 65, 134, 141 Fampridine , 79 “Gray matter” , 17, 21, 53, 126, 130, 155 Fas ligand , 3 Guillain, Georges , 93 Fas receptor , 3 Guillain–Barré syndrome (GBS) , 26, 93–100, 133, 134 Fc receptor , 8–10, 168, 169, 196 Gumma , 138 FDA , 35, 38, 42, 71, 77, 78, 105, 167–169, 171, 196, 197 FDG. See F-fl uorodeoxyglucose (FDG) F-fl uorodeoxyglucose (FDG) , 158 H Fibromyalgia , 179 HAM. See HTLV-1 associated myelopathy (HAM) Fingolimod , 63, 70, 78, 136, 171, 195–196 HAND. See HIV-associated neurocognitive disorder Fisher, Miller , 95, 96, 100 (HAND) Fisher variant of GBS , 95, 96, 100 Hashimoto’s disease , 163 Flavivirus , 130, 179 Hashimoto’s encephalopathy , 163–164 Flucytosine , 124 Heliotrope rash , 112 Fluorescence-activated cell sorting (FACS) , 13, 177 Herniation of the brain , 127 Fluorescent treponemal antibody (FTA) , 138, 145, 180 Herpes simplex encephalitis (HSE) , 115, 119, 125–133, Foam cells , 157 137, 187 Freund’s adjuvant , 84 Herpes simplex virus (HSV) , 32, 125–128, 136, 150, Frontal lobe , 18, 126, 149 161, 175 FTA. See Fluorescent treponemal antibody (FTA) Herpes zoster , 78, 136 FTA/ABS , 138, 145, 180 Heterodimer , 76 Functional MRI , 22, 23 Heterotetrameric , 151 Funny bone , 19 Heuristic , 50, 59 High erythrocyte sedimentation rate , 113 Histidyl tRNA synthetases , 113, 114 G HIV. See Human immunodefi ciency virus (HIV) GA. See Glatiramer (GA) HIV-associated neurocognitive disorder (HAND) , 128 GABA. See Gamma-aminobutyric acid (GABA) Hoffman , 22 GAD. See Glutamic acid decarboxylase (GAD) Homunculus , 23 Gadolinium , 32, 44, 45, 53, 59, 60, 64, 66, 141, hs-CRP. See C-reactive protein (hs-CRP) 153, 160 HSE. See Herpes simplex encephalitis (HSE) Gadolinium-enhancing lesion , 45, 53, 74, 137, 193, 195 HSV. See Herpes simplex virus (HSV) Galvani, Luigi , 15 HTLV-1. See Human T-lymphotropic virus-1 (HTLV-1) Gamma-aminobutyric acid (GABA) , 16, 79, 151, 162 HTLV-1 associated myelopathy (HAM) , 61, 129 Gangliosides , 95, 100, 195 Human herpes virus 8-associated Kaposi’s sarcoma , 7 GBS. See Guillain–Barré syndrome (GBS) Human immunodefi ciency virus (HIV) , 2, 6, 7, 31, 33, GCA. See Giant cell arteritis (GCA) 34, 50, 58, 60, 77, 89, 113, 117, 119, 124, 125, General paresis of the insane (GPI) , 138 128–129, 136–139, 177–179, 182–183 Gephyrin , 162 Human T-lymphotropic virus-1 (HTLV-1) , 13, 61 Giant cell arteritis (GCA) , 31, 113, 144 “Hypervariable” , 10 Giant cells , 134 Hypoglycorrhachia , 124 Glatiramer acetate (GA) , 63, 74–77 Glia , 17, 33, 99, 122 Glia limitans , 27, 28, 86, 119 I Glia limitans perivascularis , 27, 28 IBM. See Inclusion body myositis (IBM) Glia limitans superfi cialis , 27, 28 ICH. See Intracerebral hemorrhage (ICH) Glial limitans , 119 Idiopathic infl ammatory myopathies (IIMs) , 111–114 Gliosis , 148, 157, 159 IFN-a . See Interferon-a (IFN-a ) Glutamate , 16, 79 IFNAR. See Interferon-a – b receptor (IFNAR) Glutamic acid decarboxylase (GAD) , 162 IFN-b . See Interferon-b (IFN-b ) Index 203 IFN- g . See Interferon-g (IFN-g ) L IgSF. See Immunoglobulin superfamily (IgSF) LA. See Lupus anticoagulant (LA) IIMs. See Idiopathic infl ammatory myopathies (IIMs) La antigen , 180 IL-4 , 6, 87 Lambert-Eaton myasthenic syndrome (LEMS) , 26, 80, IL-5 , 6 104, 108, 109, 113, 148, 151, 152, 182 IL-6 , 6, 29, 87 Landry de Thézillat, Jean , 93 IL-10 , 6, 8, 32 Latency-associated transcripts (LATs) , 126 IL-17 , 6, 29, 86 LATs. See Latency-associated transcripts (LATs) IL-23 , 86 LEMS. See Lambert-Eaton myasthenic syndrome IL-1b , 86, 87 (LEMS) Immune privilege , 27, 28 Lepromatous leprosy , 134, 135 Immune reconstitution infl ammatory syndrome (IRIS) , Leprosy , 115, 119, 133–139 128, 129 Leukocyte immunoglobulin-like receptor (LILR) , 134 Immune thrombocytopenic purpura (ITP) , 171 Levator palpebrae , 107 Immunoblotting , 175, 177, 178, 180 Lewy bodies , 156–157 Immunoglobulin superfamily (IgSF) , 13, 99 LFA-1 , 130 Immunohistochemical/immunofl uorescence assays , 178 Lightning pains , 138 Immunological memory , 4, 7 LILR. See Leukocyte immunoglobulin-like receptor Immunoprecipitation assay , 106, 162, 181, 182 (LILR) Immunosuppressive/immunomodulatory drugs , Limbic encephalitis , 26, 148–152, 182 152, 189, 190 Lipoatrophy , 75 Imuran , 77, 192–193 Listeria monocytogenes , 122, 123 Inclusion body myositis (IBM) , 111–113 LMN. See Lower motor neuron (LMN) India ink , 124 LNB. See Lyme neuroborreliosis (LNB) Infl iximab , 11, 170 Loeffl er, Friedrich , 93 INO. See Internuclear ophthalmoplegia (INO) Louis-Antoine Ranvier , 17 iNOS. See Nitric oxide synthetase (iNOS) Lower motor neuron (LMN) , 18–21, 24, 132 Integrins , 13, 76, 77, 130, 156, 168, 197 Lupus anticoagulant (LA) , 142, 143 Interferon-a (IFN-a ) , 8, 111, 126 Lyme disease , 2–4, 50, 61, 97, 105, 115–122, 131, 137, Interferon-a – b receptor (IFNAR) , 12, 72–74 176, 179, 184, 186 Interferon-b (IFN- b ) , 11, 12, 38, 43, 52, 63, 71–75, 111, Lyme neuroborreliosis (LNB) , 13, 58, 61, 119, 178, 180, 126, 169, 184, 195 183, 186, 190 Interferon-g (IFN- g ) , 6, 12, 86 Lymphoma , 7, 50, 58, 60, 147–153, 168, 169, 177, 179, Interferons , 3, 8, 11, 72, 74, 111, 126 180, 194,

197 Interneurons , 18, 79 Lymphorrhages , 104 Internuclear ophthalmoplegia (INO) , 40, 58 Lymphotoxin , 170 Intracerebral hemorrhage (ICH) , 20 Intrathecal , 105, 119, 121–123, 185 Intravenous immunoglobulin (IVIg) , 5, 97, 98, 108, 150, M 158, 161, 169, 196, 197 MAC. See Membrane attack complex (MAC) Intrinsic factor , 65 Macrophages , 3, 6, 8, 10, 12, 17, 28, 30, 31, 33, 77, 85, IRIS. See Immune reconstitution infl ammatory syndrome 86, 89, 99, 100, 128, 134, 157, 158, 168, 170 (IRIS) MAG. See Myelin-associated glycoprotein (MAG) Isolated optic nerves , 89 Main immunogenic region (MIR) , 110 ITP. See Immune thrombocytopenic purpura (ITP) Major histocompatibility complex (MHC) , 3, 4, 8, IVIg. See Intravenous immunoglobulin (IVIg) 10–11, 30, 39, 99 MALT. See Mucosa-associated lymphoid tissue (MALT) Mamba , 104, 172, 182 J MBPs. See Myelin basic proteins (MBPs) JCV. See JC virus (JCV) McDonald criteria , 55 JC virus (JCV) , 7, 77, 117, 128, 130, 176, 179 mDCs. See Myeloid dendritic cells (mDCs) Jerne, Niels , 168 MDEM. See Multiphasic disseminated encephalomyelitis JHMV , 88 (MDEM) MDT. See Multidrug therapy (MDT) Measles inclusion body encephalitis (MIBE) , 88, 160 K Mechanoreceptors , 20 Kawasaki’s disease , 144 Medial longitudinal fasciculus (MLF) , 21, 40 Kinesins , 16 Medullary decussation , 18 Kohler, Georges , 168 Meissner’s corpuscles , 20 Kurtzke scale , 45 Membrane attack complex (MAC) , 13, 85 204 Index Memory , 4, 6–8, 13, 15, 18, 21, 30, 44, 128, 146, 149, Myelin oligodendrocyte protein (MOG) , 26, 84–87, 90, 150, 155, 162, 195, 196 171–172 Meningovascular syphilis , 60, 138 Myelin protein zero (MPZ) , 17 Men who have sex with men (MSM) , 60, 138 Myelitis , 32, 33, 50, 57, 61, 95, 122, 131 Merkel disk receptors , 20 Myeloid dendritic cells (mDCs) , 8 Methotrexate (Rheumatrex) , 11, 65, 76–78, 153, 158, 193 Myoclonic jerks , 159 MG. See Myasthenia gravis (MG) Myokymia , 162 MGUS. See Monoclonal gammopathy of unknown Myopathy , 112 signifi cance (MGUS) Myositis-specifi c autoantibodies (MSAs) , 111 MHC. See Major histocompatibility complex (MHC) Myxoma , 58, 59 MHV. See Mouse hepatitis virus (MHV) Myxovirus resistance 1 protein (MxA) , 74, 75, 111 MIBE. See Measles inclusion body encephalitis (MIBE) Microglia , 17, 30, 31, 33, 156 Migraine , 51, 58, 60, 65, 66 N Milstein, Cesar , 168 NAbs. See Neutralizing antibodies (NAbs) MIR. See Main immunogenic region (MIR) NAIM. See Nonvasculitic autoimmune infl ammatory MLF. See Medial longitudinal fasciculus (MLF) meningoencephalitis (NAIM) MOG. See Myelin oligodendrocyte protein (MOG) Naja naja , 104, 110 Molecular layer , 148 Natalizumab , 35, 76–77, 168, 197 Molecular mimicry , 95 Natural killer cells (NK cells) , 4, 6, 8, 197 Monoclonal antibody technology , 190 NCAM. See Neural cell adhesion molecule (NCAM) Monoclonal gammopathy , 98–99 Neisseria meningitidis (meningococcus) , 122, 123 M onoclonal gammopathy of unknown signifi cance Neonatal MG , 109 (MGUS) , 98, 99 Nerve conduction studies , 97, 175 Mononeuritis multiplex , 143, 144 Nerve growth factor , 99 Morvan’s syndrome , 162 Neural cell adhesion molecule (NCAM) , 8 Mouse hepatitis virus (MHV) , 87, 88, 126 Neurocysticercosis , 51, 61, 125 MPO. See Anti-myeloperoxidase (MPO) Neurofi brillary tangles , 155–156 M-protein , 99 Neurofi lament proteins , 121 MPTP , 157, 158 Neurofi laments , 16, 121, 157 MPZ. See Myelin protein zero (MPZ) Neurolemma , 23 MSAs. See Myositis-specifi c autoantibodies (MSAs) Neurologists , 15, 21, 22, 31, 37, 38, 40, 41, 43–46, 49, MSFC. See Multiple sclerosis functional composite score 50, 52, 53, 55, 57, 58, 60, 63, 64, 66, 69, 71, 72, (MSFC) 76, 78, 80, 88, 93, 94, 96–98, 104, 106–108, 112, MSM. See Men who have sex with men (MSM) 116–118, 129, 137, 141, 143–146, 149, 150, 159, MS plaque , 38, 57, 58 163, 175, 184, 189, 191, 193, 194 MS Severity Score (MSSS) , 41, 46 Neuromuscular junction (NMJ) , 15, 18, 19, 80, 103, 104, MSSS. See MS Severity Score (MSSS) 106, 107, 110, 113, 151 Mucosa-associated lymphoid tissue (MALT) , 4, 30 Neuromyelitis optica (NMO) , 18, 26, 27, 33–35, 52, Multidrug therapy (MDT) , 135 62–63, 89–90, 170, 172, 180–182, 194 Multiphasic disseminated encephalomyelitis (MDEM) , 63 Neuromyotonia , 162, 172, 182 Multiple myeloma , 98, 99 Neurons , 16–19, 23, 33, 79, 88, 95, 121, 122, 126, 130, Multiple sclerosis functional composite score (MSFC) , 45 132, 136, 148, 152, 155, 156, 162, 182 Multiple system atrophy , 157 Neuropathy , 19, 24, 33, 93, 94, 97–100, 134–136, 143, Muscle-specifi c kinase (MuSK) , 34, 106 163, 196 MuSK. See Muscle-specifi c kinase (MuSK) Neurosarcoidosis , 51, 58, 63–65, 115, 141, 142 Mutant mice , 85, 86, 100, 114, 132 Neuroscience , 15, 25, 167, 172 MxA. See Myxovirus resistance 1 protein (MxA) Neurosyphilis/Lyme disease , 2–4, 50, 54, 60–61, 97, Myasthenia gravis (MG) , 12, 19, 26, 34, 35, 75, 80, 105, 115–122, 124, 131, 137–139, 176, 179, 90, 103–111, 113, 172, 181, 182, 190, 193, 180, 184, 186 197, 198 Neurotransmitters , 15–16, 19, 79, 109, 147, 156, 162 Myasthenic crisis , 106, 108, 197 Neurovascular unit , 20, 27, 28 Mycobacterium leprae , 134, 135 Neutralizing antibodies (NAbs) , 35, 74, 75, 77, 126 Mycobacterium tuberculosis , 61, 117, 124, 141, 187 NF-kappa B. See Nuclear factor-kappa B (NF-kappa B) Mycophenolate (CellCept) , 63, 108, 130, 192, 194 Nitric oxide (NO) , 8 Myelin , 16, 17, 24, 30–32, 37–39, 41, 52, 53, 84–86, 89, Nitric oxide synthetase (iNOS) , 8 95, 99, 100, 121, 171, 172 NK cells. See Natural killer cells (NK cells) Myelin-associated glycoprotein (MAG) , 17, 99 NMDA receptor. See n -methyl-D -aspartic acid (NMDA) Myelin basic proteins (MBPs) , 17, 26, 29, 30, 75, 84, receptor 87, 121, 163 n -methyl-D -aspartic acid (NMDA) receptor , 148, 150–152 Index 205 NMJ. See Neuromuscular junction (NMJ) Paraneoplastic syndrome(s) , 27, 63, 111, 147–153, 162, NMO. See Neuromyelitis optica (NMO) 180, 197 NMT. See Acquired neuromyotonia (NMT) Parietal lobe , 18 NNH. See Number needed to harm (NNH) Parkinson-plus complex , 156–157 NNT. See Number needed to treat (NNT) Parkinson’s disease (PD) , 145, 155–158, 173 NO. See Nitric oxide (NO) PAS. See Periodic acid-Schiff (PAS) Nociceptors , 20 PASAT. See Paced auditory serial addition test (PASAT) Nodes of Ranvier , 17, 95 Passive transfer , 87, 89–90, 152, 162, 181 Nonsteroidal anti-infl ammatory drugs (NSAIDs) , Pathergy test , 164 64, 123, 125, 156, 158 Pathogen-associated molecular patterns (PAMPs) , 8 Nonvasculitic autoimmune infl ammatory Pattern recognition receptors (PRRs) , 8 meningoencephalitis (NAIM) , 163 Paucibacillary leprosy , 134 Norepinephrine , 16 PCD. See Paraneoplastic cerebellar degeneration (PCD); NSAIDs. See Nonsteroidal anti-infl ammatory drugs Programmed cell death (PCD) (NSAIDs) PCR. See Polymerase chain reaction (PCR) Nuclear factor-kappa B (NF-kappa B) , 190 PD. See Parkinson’s disease (PD); Number needed to harm (NNH) , 189 Pharmacodynamics (PD) Number needed to treat (NNT) , 189 pDCs. See Plasmacytoid dendritic cells (pDCs) Nystagmus , 21, 44 Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) , 26, 162 O Pelizaeus-Merzbacher disease , 17 OCBs. See Oligoclonal (immunoglobulin) bands (OCBs) PEP. See Postexposure prophylaxis (PEP) Occipital lobes , 18, 20 Pericyte , 27, 28 Ocrelizumab , 169, 197 Perifascicular atrophy , 111 Ofatumumab , 169 Perikaryon , 27, 28 OIs. See Opportunistic infections (OIs) Perimysium , 111 Oligoclonal (immunoglobulin) bands (OCBs) , 52, 54, Perineurium , 121 58–60, 62, 63, 65, 66, 143, 152, 181, 184–186 Periodic acid-Schiff (PAS) , 160 Oligodendrocytes , 17–18, 23, 89, 126, 130, 171 Peripheral lymphoid organs , 4 Omega-conotoxin , 104, 108 Peripheral nervous system (PNS) , 15–21, 23, 24, 26, Ophthalmoplegia , 40, 58, 96, 97 27, 32, 37, 93, 99, 115, 133, 143–145, 183 Opiate peptides , 79 Perivascular space , 27, 28, 32, 86 Opportunistic infections (OIs) , 6, 7, 11, 33, 58, 60, 117, Pernicious anemia , 65, 160 128, 130, 136, 137, 195, 196 Pertussis toxin , 84, 87 Opsoclonus (opsoclonus-myoclonus) , 150, 152 PET. See Positron emission tomography (PET) Optic neuritis , 20, 40, 41, 50, 52, 57, 63, 72, 181, PGL-1. See Phenolic glycolipid-1 (PGL-1) 184, 189 Pharmacodynamics (PD) , 69 Opticospinal MS , 62 Pharmacokinetics (PK) , 69 OraQuick , 179 Phase 0 study , 69, 70 Osteosclerotic , 99 Phase 1 study , 69–70 Ovarian teratomas , 150, 151 Phase 2 study , 70, 187, 188, 197 Phase 3 study , 8, 70, 74, 75, 78, 168, 173, 197 Phenolic glycolipid-1 (PGL-1) , 135 P Phospholipids , 138, 142, 180 P0 , 26, 99 Pia mater , 20, 28, 119 P2 , 26 PK. See Pharmacokinetics (PK) p75 , 99, 169 Placebo , 54, 70, 71, 74, 75, 167, 189, 196 Paced auditory serial addition test (PASAT) , 45 Placebo-controlled , 70, 196 Pacinian corpuscles , 20 Plasma , 95, 97, 98, 117, 129, 152, 171, 176, 197 PACNS. See Primary angiitis of the CNS (PACNS) Plasma cells , 4, 8, 9, 30, 39, 54, 88, 89, 98, 99, 126, PAMPs. See Pathogen-associated molecular patterns 134, 160, 169, 185, 186 (PAMPs) Plasmacytoid dendritic cells (pDCs) , 8, 111 PANDAS. See Pediatric autoimmune neuropsychiatric Plasma exchange , 34, 97, 98, 152, 197 disorders associated with streptococcal infection Plasmapheresis , 63, 95, 96, 108, 161, 197 (PANDAS) PLP. See Proteolipid protein (PLP) Paramyxovirus , 160 PML. See Progressive multifocal leukoencephalopathy Paraneoplastic cerebellar degeneration (PCD) , 16, 35, 148 (PML) Paraneoplastic neurological disorders (PNDs) , PMNs. See Polymorphonuclear leukocytes (PMNs) 147–152, 182 PMP , 99, 100 22 206 Index PMR. See Polymyalgia rheumatica (PMR) Rheumatoid arthritis (RA) , 11–12, 105, 112, 113, 115, PNDs. See Paraneoplastic neurological disorders (PNDs) 141, 167, 170, 171, 193 Pneumocystis , 7, 11 Rituximab , 4, 26, 35, 130, 137, 153, 168, 169, 187, 197 PNS. See Peripheral nervous system (PNS) Ro antigen , 180 POEMS , 99 Rotenone , 157 Polyarteritis nodosa , 144 RPR. See Rapid Plasma Reagin (RPR) Polymerase chain reaction (PCR) , 31, 35, 117, 127, 131, Ryanodine receptor , 105 136, 150, 160, 161, 175, 180, 182–183, 186, 187 Polymorphonuclear leukocytes (PMNs) , 3, 7–8, 123–125, 187 S Polymyalgia rheumatica (PMR) , 113, 144 SAH. See Subarachnoid hemorrhage (SAH) Polymyositis , 108, 111–113 Saltatory , 16 Polyomavirus , 7 Saltpetrière , 22, 38 Pompe’s disease , 167 Santiago Ramón y Cajal, Poser criteria , 55 Sarcoidosis , 50, 63, 64, 122, 141 Positron emission tomography (PET) , 158 SC. See Sydenham’s chorea (SC) Postexposure prophylaxis (PEP) , 133 Schumacher criteria , 55, 59 Post-herpetic neuralgia , 136 Schwann, Theodor , 17 Post-vaccinial encephalomyelitis , 25–29, 75, 83 Schwann cells (SCs) , 17, 23, 100, 134 PPMS. See Primary progressive MS (PPMS) “Sclérose en plaques” (SP) , 39 Predictive value , 53, 175, 176, 184, 186 SCs. See Schwann cells (SCs) Presenile dementia , 155 SDH. See Subdural hemorrhage (SDH) Primary angiitis of the CNS (PACNS) , 145, 146 Secondary APS , 142, 143, 145, 180 Primary APS , 142 Secondary progressive MS (SPMS) , 43, 44 Primary CNS lymphoma , 60, 147–153 Selectins , 13 Primary lymphoid organs , 4 Semple rabies vaccine autoimmune encephalomyelitis , Primary motor cortex , 18 29–31, 77, 85 Primary progressive , 37 Senile plaques , 155, 156 Primary progressive MS (PPMS) , 43, 44, 63 Sensitivity , 40, 122, 175, 176, 181, 184, 186, 187 Product insert , 77 Serious adverse events , 76 Programmed cell death (PCD) , 3, 7, 85, 100, 149 Serology , 61, 117, 131, 177, 179, 180 Progressive multifocal leukoencephalopathy (PML) , Seronegative , 77, 106, 182 7, 33, 60, 77, 117, 126, 129–131, 137, 168, 179, Serum , 10, 34, 54, 60–62, 74, 77, 95, 98, 103, 106, 187, 194 115, 118, 122, 123, 129, 131, 138, 142, 145, Progressive supranuclear palsy , 157 147, 149, 151, 158, 169, 170, 175, 176, Projection neurons , 18, 79 178–182, 185–187, 196 Proteolipid protein (PLP) , 17, 26, 84, 86 Serum protein electrophoresis (SPEP) , 98, 99 PRRs. See Pattern recognition receptors (PRRs) Shingles , 33, 78, 136 Ptosis , 106, 107 Sjogren’s syndrome , 65, 112, 143–144, 180 Purkinje cell(s) , 16, 35, 148, 182 SLE. See Systemic lupus erythematosus (SLE) Purkinje layer , 148 Soma , 16, 27

Pyrimethamine , 117, 128, 137 Somatic hypermutation , 5, 10 Somatostatin , 79 SP. See “Sclérose en plaques” (SP) R S1P. See Sphingosine-1 phosphate (S1P) RA. See Rheumatoid arthritis (RA) Specifi city , 3, 35, 107, 121, 122, 168, 171, 175, 176, 181, Rabies , 25–26, 29–31, 83, 85, 132–133 184, 185, 187 Raised intracranial pressure , 124, 127, 164 SPEP. See Serum protein electrophoresis (SPEP) Randomized , 70, 72, 167, 189, 196 Sphingosine-1 phosphate (S1P) , 13, 78, 171, 195 Rapid Plasma Reagin (RPR) , 33, 142, 180 Spike and wave forms , 24 Rasmussen’s encephalitis , 26, 164 Spinal cord , 15, 17, 18, 20, 22, 24, 26, 30, 32, 39, 44, Reaginic (antibody) tests , 180, 186 50–52, 54, 57, 59, 61, 62, 65, 79, 84, 86, 89, 95, Recombinant DNA , 169 115, 129, 132, 145, 147, 153, 159, 162, 163, 181 Refl exes , 15, 20–22, 51, 52, 106, 108 Spinal cord atrophy , 42 Relapse , 38, 40–46, 50, 63, 70, 71, 74, 75, 78, SPMS. See Secondary progressive MS (SPMS) 88, 98, 136 Spontaneous activity , 162 Relapsing-remitting MS (RRMS) , 42–44, 77 SPS. See Stiff person syndrome (SPS) Retrovirus , 6, 61, 89, 129 SREAT. See Steroid-responsive encephalopathy Reverse transcriptase , 182, 186 associated with autoimmune thyroiditis (SREAT) Index 207 SS-A antigen , 180 Toll-like receptors (TLRs) , 3, 8, 84, 134, 190 SS-B antigen , 180 Toxoplasma gondii , 117, 129, 137 SSPE. See Subacute sclerosing panencephalitis (SSPE) Toxoplasmosis , 7, 33, 60, 113, 116, 117, 137 Steroid-responsive encephalopathy associated with TPHA. See Treponema pallidum hemagglutination assay autoimmune thyroiditis (SREAT) , 163 (TPHA) Stiff person syndrome (SPS) , 26, 162, 196, 197 TRAL. See Treatment-related acute leukemias (TRAL) Stocking-glove , 19, 143 Transforming growth factor-b (TGF-b ) , 12, 29, 32, 86, 87 Streptococcus pneumoniae (pneumococcus) , 122, 123 Treatment-related acute leukemias (TRAL) , 77 Strohl, Andre , 93, 97 Treponema pallidum , 120, 123, 124, 137, 186 Subacute combined degeneration , 65 Treponema pallidum hemagglutination assay (TPHA) , 180 Subacute sclerosing panencephalitis (SSPE) , 88, 159–160 Trigeminal ganglion , 126 Subarachnoid hemorrhage (SAH) , 20, 145 “Trimolecular complex” , 4 Subcortical dementia , 63, 128 Tropheryma whipplei , 160 Subdural hemorrhage (SDH) , 20 Tropical spastic paraparesis (TSP) , 61, 128, 129 Substantia nigra , 156, 157 TSP. See Tropical spastic paraparesis (TSP) Sulfadiazine , 117, 137 Tuberculoid leprosy , 134, 135 Surface markers , 6, 177, 197 Tuberculosis (TB) , 7, 51, 61–62, 78, 116, 117, 122, 125, Swine-worker’s neuropathy , 163 128, 129, 134, 135, 141, 180, 187, 188 Sydenham’s chorea (SC) , 134, 161–162 Tumefactive MS , 62 Symptomatic therapies , 69, 78–80 Tumor necrosis factor (TNF) , 3, 11, 12, 169–171 Synapses , 15, 16 Tumor necrosis factor-a (TNF-a ) , 11, 12, 87, 169, 170 Systemic lupus erythematosus (SLE) , 50, 58, 105, Tumor necrosis factor-b (TNF-b ) , 6, 170 112, 141–142, 145, 180, 191 Type 1 interferon , 126 T U Tabes dorsalis , 138 Ulnar nerve , 19, 135 Taenia solium , 61, 187 UMN. See Upper motor neuron (UMN) Takayasu’s arteritis , 144 Upper motor neuron (UMN) , 20, 24, 132 Tandem gait , 22, 44 Tania solium , 129 Tau , 156 V TB. See Tuberculosis (TB) Valaciclovir (Valrex) , 136 T cell. See Thymus-derived cell (T cell) Varicella zoster virus (VZV) , 33, 133–136, 144, 161, 180 T cell receptor (TCR) complexes , 4–6, 87 Vasa nervorum , 144 TCR. See T cell receptor (TCR) complexes Vasculitis , 31, 58, 65, 97, 113, 118, 144–146, 164 Tegument , 126 VCAM-1 , 76 Temporal arteritis , 113 VDRL. See Venereal Disease Research Laboratory Temporal lobe , 18, 31, 32, 126, 127, 146, 150, 152 (VDRL) test Tensilon test , 107 Venereal Disease Research Laboratory (VDRL) test , TGF- b . See Transforming growth factor-b (TGF-b ) 33, 60, 138, 142, 145, 180, 186 Th1 cells , 6, 33, 86, 87 Vertebrae , 18, 29 Th17 cells , 6, 29, 33, 86, 87 Very late antigen-4 (VLA-4) , 76 Theiler’s murine encephalomyelitis virus (TMEV) , VGCCs. See Voltage-gated calcium channels (VGCCs) 87–89, 120, 132 VGKCs. See Voltage-gated potassium channels (VG- Thrombocytopenia , 197 KCs) Thymic hyperplasia , 105, 106 Viral DNA polymerase , 128 Thymomas , 105, 106, 162 Virchow-Robins spaces , 32 Thymus-derived cell (T cell) , 3–8, 10, 12, 13, 26, 29–34, Visna virus , 87, 89 38, 77, 85–87, 100, 110, 126, 129, 148, 151, 153, VLA-4. See Very late antigen-4 (VLA-4) 157, 168, 171, 188, 191, 194–197 Voltage-gated calcium channels (VGCCs) , 104, 108–109, Titin , 105, 107 151, 172, 182 Tizanidine , 16, 79 Voltage-gated potassium channels (VGKCs) , 80, 104, TLRs. See Toll-like receptors (TLRs) 108, 151, 152, 162, 172, 182 TMEV. See Theiler’s murine encephalomyelitis virus VZV. See Varicella zoster virus (VZV) (TMEV) TNF. See Tumor necrosis factor (TNF) TNF- a . See Tumor necrosis factor-a (TNF-a ) W TNF- b . See Tumor necrosis factor-b (TNF-b ) Wallerian degeneration , 23, 96 Tolerance , 7 Wegener’s granulomatosis , 65, 144, 148 208 Index Westergren sedimentation rate (WSR) , 177 WNV. See West Nile virus (WNV) Western blotting , 177, 178 WSR. See Westergren sedimentation rate (WSR) West Nile virus (WNV) , 35, 130–131, 179 Whipple’s disease , 160–161 Z “White matter” , 17, 39–42, 44, 51, 53, Zenapax , 197 55, 58–66, 118, 126, 130, 131, Ziconotide , 105 153, 164, 184 Zoster sine herpete , 136

Copyright © 2002 F.A. Davis Company Clinical Applications of Nursing Diagnosis Copyright © 2002 F.A. Davis Company Helen C. Cox, RN, C, EdD, FAAN PROFESSOR EMERITUS TEXAS TECH UNIVERSITY HEALTH SCIENCES CENTER SCHOOL OF NURSING LUBBOCK, TEXAS Mittie D. Hinz, RN, C, MSN, MBA DIRECTOR OF WOMEN’S AND CHILDREN’S SERVICES ARLINGTON MEMORIAL HOSPITAL ARLINGTON, TEXAS Mary Ann Lubno, RN, PhD, CNAA CASE MANAGER GENTIVA HEALTH SERVICES PHOENIX, ARIZONA Donna Scott-Tilley, RN, MSN, CRNH INSTRUCTOR OF CLINICAL NURSING TEXAS TECH UNIVERSITY HEALTH SCIENCES CENTER SCHOOL OF NURSING LUBBOCK, TEXAS Susan A. Newfield, RN, PhD, CS VISITING ASSISTANT PROFESSOR OF NURSING ROBERT C. BYRD HEALTH SCIENCES CENTER SCHOOL OF NURSING WEST VIRGINIA UNIVERSITY MORGANTOWN, WEST VIRGINIA Mary McCarthy Slater, RN, C, MSN ASSOCIATE PROFESSOR OF NURSING EASTERN KENTUCKY UNIVERSITY, COLLEGE OF HEALTH SCIENCES RICHMOND, KENTUCKY Kathryn L. Sridaromont, RN, C, MSN ASSOCIATE PROFESSOR OF CLINICAL NURSING TEXAS TECH UNIVERSITY HEALTH SCIENCES CENTER SCHOOL OF NURSING LUBBOCK, TEXAS Copyright © 2002 F.A. Davis Company Clinical Applications of Nursing Diagnosis Adult, Child, Women’s, Psychiatric, Gerontic and Home Health Considerations Fourth Edition F. A. DAVIS COMPANY • Philadelphia Copyright © 2002 F.A. Davis Company F. A. Davis Company 1915 Arch Street Philadelphia, PA 19103 www.fadavis.com Copyright © 2002 by F. A. Davis Company Copyright © 1989, 1993, 1997 by F. A. Davis Company. All rights reserved. This book is protected by copyright. No part of it may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, me- chanical, photocopying, recording, or otherwise, without written permission from the publisher. Printed in the United States of America Last digit indicates print number: 10 9 8 7 6 5 4 3 2 1 Publisher, Nursing: Robert G. Martone Production Editor: Jack C. Brandt Cover Designer: Louis J. Forgione As new scientific information becomes available through basic and clinical research, recommended treatments and drug therapies undergo changes. The authors and publisher have done everything possible to make this book accu- rate, up to date, and in accord with accepted standards at the time of publication. The authors, editors, and publisher are not responsible for errors or omissions or for consequences from application of the book, and make no warranty, expressed or implied, in regard to the contents of the book. Any practice described in this book should be applied by the reader in accordance with professional standards of care used in regard to the unique circumstances that may ap- ply in each situation. The reader is advised always to check product information (package inserts) for changes and new information regarding dose and contraindications before administering any drug. Caution is especially urged when using new or infrequently ordered drugs. Library of Congress Cataloging-in-Publication Data Clinical applications of nursing diagnosis : adult, child, women's, psychiatric, gerontic, and home health considerations / [editors, Helen C. Cox . et al.].-- 4th ed. p. cm. Includes bibliographical references and index. ISBN 0-8036-0913-2 (alk. paper) 1. Nursing diagnosis. 2. Nursing assessment. 3. Nursing. I. Cox, Helen C. RT48.6 .C6 2002 610.73--dc21 2001047231 Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by F. A. Davis Company for users registered with the Copyright Clearance Center (CCC) Transactional Re- porting Service, provided that the fee of $.10 per copy is paid directly to CCC, 222 Rosewood Drive, Danvers, MA 01923. For those organizations that have been granted a photocopy license by CCC, a separate system of payment has been arranged. The fee code for users of the Transactional Reporting Service is: 8036–0913/02 0
$.10. Copyright © 2002 F.A. Davis Company To the administration, faculty, students, and staff of Texas Tech University Health Sciences Center School of Nursing for support and encouragement above and beyond the usual. Copyright © 2002 F.A. Davis Company This page intentionally left blank Copyright © 2002 F.A. Davis Company Preface The North American Nursing Diagnosis Association (NANDA) has been identifying, classifying, and testing diagnostic nomenclature since the early 1970s. In our opinion, use of nursing diag- nosis helps define the essence of nursing and give direction to care that is uniquely nursing care. If nurses (in all instances we are referring to registered nurses) enter the medical diagnosis of, for example, acute appendicitis as the patient’s problem, they have met defeat before they have begun. A nurse cannot intervene for this medical diagnosis; intervention requires a medical practitioner who can perform an appendectomy. However, if the nurse enters the nursing diagnosis “Pain,” then a number of nursing interventions come to mind. Several books incorporate nursing diagnosis as a part of planning care. However, these books generally focus outcome and nursing interventions on the related factors; that is, nursing inter- ventions deal with resolving, to the extent possible, the causative and contributing factors that re- sult in the nursing diagnosis. We have chosen to focus nursing intervention on the nursing diag- nosis. To focus on the nursing diagnosis promotes the use of concepts in nursing rather than concentrating on a multitude of specifics. For example, there are common nursing measures that can be used to relieve pain regardless of the etiologic pain factor involved. Likewise, the outcomes focus on the nursing diagnosis. The main outcome nurses want to achieve when working with the nursing diagnosis Pain is control of the patient’s response to pain to the extent possible. Again, the outcome allows the use of a conceptual approach rather than a multitude-of-specifics approach. To clarify further, consider again the medical diagnosis of appendicitis. The physician’s first con- cern is not related to whether the appendicitis is caused by a fecalith, intestinal helminths, or Escherichia coli run amok. The physician focuses first on intervening for the appendicitis, which usually results in an appendectomy. The physician will deal with etiologic factors following the appendectomy, but the appendectomy is the first level of intervention. Likewise, the nurse can deal with the related factors through nursing actions, but the first level of intervention is directed to re- solving the patient’s problem as reflected by the nursing diagnosis. With the decreasing length of stay for the majority of patients entering a hospital, we may indeed do well to complete the first level of nursing actions. Additionally, there is continuing debate among NANDA members as to whether the current list of diagnoses that are accepted for testing are nursing diagnoses or a list of diagnostic categories or concepts. We, therefore, have chosen to focus on concepts. Using a conceptual approach al- lows focus on independent nursing functions and helps avoid focusing on medical intervention. This book has been designed to serve as a guide to using NANDA-accepted nursing diagnoses as the primary base for the planning of care. The expected outcomes, target dates, nursing actions, and evaluation algorithms (flowcharts) are not meant to serve as standardized plans of care but rather as guides and references in promoting the visibility of nursing’s contribution to health care. Marjory Gordon’s Functional Health Patterns are used as an organizing framework for the book. The Functional Health Patterns allow categorizing of the nursing diagnoses into specific groups, which, in our opinion, promotes a conceptual approach to assessment and formulation of a nursing diagnosis. Chapter 1 serves as the overview-introductory chapter and gives basic content related to the process of planning care and information regarding the relationship between nursing process and nursing models (theories). Titles for Chapters 2 through 12 are taken from the functional pat- terns. Included in each of these chapters is a list of diagnoses within the pattern, a pattern de- scription, pattern assessment, conceptual information, and developmental information related to the pattern. The pattern description gives a succinct summary of the pattern’s content and assists in explain- ing how the diagnoses within the pattern are related. The list of diagnoses within the pattern is given vii Copyright © 2002 F.A. Davis Company viii PREFACE to simplify location of the diagnoses. The pattern assessment serves to pinpoint information from the initial assessment base and was specifically written to direct the reader to the most likely diagnosis within the pattern. Each assessment factor is designed to allow an answer of “yes” or “no.” If the pa- tient’s answer or signs are indicative of a diagnosis within the pattern, the reader is directed to the most likely diagnosis or diagnoses. The conceptual and developmental information is included to provide a quick, ready reference to the physiologic, psychological, sociologic, and age-related fac- tors that could cause modification of the nursing actions in order to make them more specific for your patient. The conceptual and developmental information can be used to determine the rationale for each nursing action. Each nursing diagnosis within the pattern is then introduced with accompanying information of definition, defining characteristics, and related factors. We have added a section titled “Related Clinical Concerns.” This section serves to highlight the most common medical diagnoses or clus- ter of diagnoses that could involve the individual nursing diagnosis. Immediately after the related clinical concerns section is a section titled “Have you selected the correct diagnosis?” This section was included as a validation check because we realize that sev- eral of the diagnoses appear very closely related and that it can be difficult to distinguish between them. This is, in part, related to the fact that the diagnoses have been accepted for testing, not as statements of absolute, discrete diagnoses. Thus, having this section assists the reader in learning how to pinpoint the differences between diagnoses and in feeling more comfortable in selecting a diagnosis that most clearly reflects a patient’s problem area that can be helped by nursing ac- tions. After the diagnosis validation section is an outcome. The expected outcome serves as the end point against which progress can be measured. Different agencies may call the expected outcome an objective, a patient goal, or an outcome standard. Readers may also choose to design their own patient-specific expected outcome using the given expected outcome as a guideline. Target dates are suggested following the expected outcome. The target dates do not indicate the time or day the outcome must be fully achieved; instead, the target date signifies the time or day when evaluation should be completed in order to measure the patient’s progress toward achieve- ment of the expected outcome. Target dates are given in reference to short-term care. For home health, particularly, the target date would be in terms of weeks and months rather than days. Nursing actions/interventions and rationales are the next information given. In most instances, the adult health nursing actions serve as the generic nursing actions. Subsequent sets of nursing actions (child health, women’s health, psychiatric health, gerontic health, and home health) show only the nursing actions that are different from the generic nursing actions. The different nursing actions make each set specific for the target population, but must be used in conjunction with the adult health nursing actions to be complete. Rationales have been included to assist the student in learning the reason for particular nursing actions. Although some of the rationales are scien- tific in nature, that is, supported by documented research, other rationales could be more ap- propriately termed “common sense” or “usual practice rationales.” These rationales are reasons nurses have cited for particular nursing actions and result from nursing experience, but research has not been conducted to document these rationales. After the home health actions, evaluation algorithms are shown that help judge the patient’s progress toward achieving the expected out- come. Evaluation of the patient’s care is based on the degree of progress the patient has made toward achieving the expected outcome. For each stated outcome, there is an evaluation flowchart (al- gorithm). The flowcharts provide minimum information, but demonstrate the decision-making process that must be used. In all instances, the authors have used the definitions, defining characteristics, and related fac- tors that have been accepted by NANDA for testing. A grant was provided to NANDA by the F. A. Davis Company for the use of these materials. All these materials may be ordered from NANDA (1211 Locust Street, Philadelphia, PA 19107). Likewise, a fee was paid to Mosby for the use of the domains and classes from McCloskey, JC, and Bulechek, GM (eds): Nursing Interventions Clas- sification (NIC), edition 3 (Mosby, St. Louis, 2000) and Johnson, M,

Maas, M, and Moorhead, S (eds): Nursing Outcomes Classification, edition 2 (Mosby, St. Louis, 2000). In some instances, additional information is included following a set of nursing actions. The additional information includes material that either needs to be highlighted or does not logically fall within the defined outline areas. Throughout the nursing actions we have used the terms patient and client interchangeably. The terms refer to the system of care and include the individual as well as the family and other social support systems. The nursing actions are written very specifically. This specificity aids in com- munication between and among nurses and promotes consistency of care for the patient. There has been a tremendous increase in the activity of NANDA. In 1998 alone, 16 new diag- Copyright © 2002 F.A. Davis Company PREFACE ix noses were accepted, 32 diagnoses were revised, and one diagnosis was deleted. The official jour- nal of NANDA became an international journal in 1999. The fourth edition incorporates new and revised diagnoses from both the Thirteenth (1998) and Fourteenth (2000) NANDA Conferences. The proposed NANDA Taxonomy 2 has been in- serted to replace the old Taxonomy 1, Revised. The Nursing Interventions Classification (NIC) system and the Nursing Outcomes Classification (NOC) system domains and classes have been incorporated. Other revisions have been made to be consistent with current NANDA thought and publica- tions. One example is the deletion of major and minor defining characteristics and their assimi- lation under one heading of “Defining Characteristics.” We continue to appreciate the feedback we have received from various sources and urge you to continue to assist us in this way. It is our sincerest wish that this book will continue to assist nurses and nursing students in their day-to-day use of nursing diagnosis. Helen C. Cox, RN, C, EdD, FAAN Copyright © 2002 F.A. Davis Company Acknowledgments The publication of a book necessitates the involvement of many per- sons beyond the authors. We wish to acknowledge the support and assis- tance of the following persons who indeed made this book possible: Our families, who supported our taking time away from family ac- tivities Bob Martone, Publisher, Nursing, whose enthusiasm and belief in the book was most gratifying and helpful AND A special acknowledgment to Dr. Marjory Gordon, a most gracious lady who freely shared ideas, materials, support, and encourage- ment To each of these persons we wish to say a heartfelt “Thank you.” Please accept our deepest gratitude and appreciation. x Copyright © 2002 F.A. Davis Company Contents CHAPTER 1 Introduction 1 WHY THIS BOOK?, 1 THE NURSING PROCESS, 1 Purpose, 1 Definition, 1 Role in Planning Care, 2 Care Plan versus Planning of Care, 2 NURSING PROCESS STEPS, 3 Assessment, 3 Diagnosis, 4 Planning, 5 Implementation, 6 Documentation, 7 Evaluation, 9 NURSING PROCESS AND CONCEPTUAL FRAMEWORKS, 9 Nursing Models, 9 Patterns, 10 VALUING PLANNING OF CARE AND CARE PLANS, 13 SUMMARY, 14 CHAPTER 2 Health Perception–Health Management Pattern 15 PATTERN DESCRIPTION, 15 PATTERN ASSESSMENT, 15 CONCEPTUAL INFORMATION, 16 DEVELOPMENTAL CONSIDERATIONS, 18 APPLICABLE NURSING DIAGNOSES, 21 Energy Field, Disturbed, 21 Health Maintenance, Ineffective, 27 Health-Seeking Behaviors (Specify), 33 Infection, Risk for, 37 Injury, Risk for, 42 Latex Allergy Response, Risk for and Actual, 51 Management of Therapeutic Regimen, Effective, 57 Management of Therapeutic Regimen (Individual, Family, Community), Ineffective, 61 Perioperative-Positioning Injury, Risk for, 71 xi Copyright © 2002 F.A. Davis Company xii CONTENTS Protection, Ineffective, 75 Surgical Recovery, Delayed, 81 CHAPTER 3 Nutritional-Metabolic Pattern 86 PATTERN DESCRIPTION, 86 PATTERN ASSESSMENT, 86 CONCEPTUAL INFORMATION, 87 DEVELOPMENTAL CONSIDERATIONS, 89 APPLICABLE NURSING DIAGNOSES, 92 Adult Failure to Thrive, 92 Aspiration, Risk for, 97 Body Temperature, Imbalanced, Risk for, 102 Breastfeeding, Effective, 107 Breastfeeding, Ineffective, 110 Breastfeeding, Interrupted, 115 Dentition, Impaired, 119 Fluid Volume, Deficient, Risk for and Actual, 123 Fluid Volume, Excess, 129 Fluid Volume, Imbalanced, Risk for, 136 Hyperthermia, 140 Hypothermia, 145 Infant Feeding Pattern, Ineffective, 150 Nausea, 153 Nutrition, Imbalanced, Less Than Body Requirements, 157 Nutrition, Imbalanced, More Than Body Requirements, Risk for and Actual, 166 Swallowing, Impaired, 173 Thermoregulation, Ineffective, 178 Tissue Integrity, Impaired, 181 CHAPTER 4 Elimination Pattern 191 PATTERN DESCRIPTION, 191 PATTERN ASSESSMENT, 191 CONCEPTUAL INFORMATION, 192 DEVELOPMENTAL CONSIDERATIONS, 193 APPLICABLE NURSING DIAGNOSES, 195 Bowel Incontinence, 195 Constipation, Risk for, Actual, and Perceived, 199 Diarrhea, 206 Urinary Incontinence, 211 Urinary Retention, 219 CHAPTER 5 Activity-Exercise Pattern 224 PATTERN DESCRIPTION, 224 PATTERN ASSESSMENT, 224 CONCEPTUAL INFORMATION, 226 DEVELOPMENTAL CONSIDERATIONS, 226 APPLICABLE NURSING DIAGNOSES, 231 Activity Intolerance, Risk for and Actual, 231 Airway Clearance, Ineffective, 239 Copyright © 2002 F.A. Davis Company CONTENTS xiii Autonomic Dysreflexia, Risk for and Actual, 246 Bed Mobility, Impaired, 251 Breathing Pattern, Ineffective, 256 Cardiac Output, Decreased, 262 Disuse Syndrome, Risk for, 270 Diversional Activity, Deficient, 275 Dysfunctional Ventilatory Weaning Response (DVWR), 280 Falls, Risk for, 285 Fatigue, 289 Gas Exchange, Impaired, 294 Growth and Development, Delayed; Disproportionate Growth, Risk for; Delayed Development, Risk for, 301 Home Maintenance, Impaired, 308 Infant Behavior, Disorganized, Risk for and Actual, and Readiness for Enhanced Organized, 313 Peripheral Neurovascular Dysfunction, Risk for, 318 Physical Mobility, Impaired, 322 Self-Care Deficit (Feeding, Bathing-Hygiene, Dressing-Grooming, Toileting), 330 Spontaneous Ventilation, Impaired, 337 Tissue Perfusion, Ineffective (Specify Type: Renal, Cerebral, Cardiopulmonary, Gastrointestinal, Peripheral), 341 Transfer Ability, Impaired, 350 Walking, Impaired, 356 Wandering, 360 Wheelchair Mobility, Impaired, 364 CHAPTER 6 Sleep-Rest Pattern 367 PATTERN DESCRIPTION, 367 PATTERN ASSESSMENT, 367 CONCEPTUAL INFORMATION, 367 DEVELOPMENTAL CONSIDERATIONS, 368 APPLICABLE NURSING DIAGNOSES, 369 Sleep Deprivation, 369 Sleep Pattern, Disturbed, 375 CHAPTER 7 Cognitive-Perceptual Pattern 381 PATTERN DESCRIPTION, 381 PATTERN ASSESSMENT, 381 CONCEPTUAL INFORMATION, 382 DEVELOPMENTAL CONSIDERATIONS, 382 APPLICABLE NURSING DIAGNOSES, 385 Adaptive Capacity, Intracranial, Decreased, 385 Confusion, Acute and Chronic, 391 Decisional Conflict (Specify), 400 Environmental Interpretation Syndrome, Impaired, 406 Knowledge, Deficient (Specify), 410 Memory, Impaired, 416 Pain, Acute and Chronic, 421 Sensory Perception, Disturbed (Specify: Visual, Auditory, Kinesthetic, Gustatory, Tactile, Olfactory), 431 Copyright © 2002 F.A. Davis Company xiv CONTENTS Thought Process, Disturbed, 440 Unilateral Neglect, 447 CHAPTER 8 Self-Perception and Self-Concept Pattern 451 PATTERN DESCRIPTION, 451 PATTERN ASSESSMENT, 451 CONCEPTUAL INFORMATION, 452 DEVELOPMENTAL CONSIDERATIONS, 453 APPLICABLE NURSING DIAGNOSES, 456 Anxiety, 456 Body Image, Disturbed, 465 Death Anxiety, 471 Fear, 476 Hopelessness, 484 Loneliness, Risk for, 491 Personal Identity, Disturbed, 497 Powerlessness, Risk for and Actual, 501 Self-Esteem, Chronic Low, Situational Low, and Risk for Situational Low, 508 Self-Mutilation, Risk for and Actual, 515 CHAPTER 9 Role-Relationship Pattern 520 PATTERN DESCRIPTION, 520 PATTERN ASSESSMENT, 520 CONCEPTUAL INFORMATION, 521 DEVELOPMENTAL CONSIDERATIONS, 522 APPLICABLE NURSING DIAGNOSES, 526 Caregiver Role Strain, Risk for and Actual, 526 Family Processes, Interrupted, and Family Processes, Dysfunctional: Alcoholism, 534 Grieving, Anticipatory, 544 Grieving, Dysfunctional, 551 Parent, Infant, and Child Attachment, Impaired, Risk for, 557 Parenting, Impaired, Risk for and Actual, and Parental Role Conflict, 561 Relocation Stress Syndrome, Risk for and Actual, 570 Role Performance, Ineffective, 574 Social Interaction, Impaired, 580 Social Isolation, 585 Sorrow, Chronic, 591 Verbal Communication, Impaired, 596 Violence, Self-Directed and Other-Directed, Risk for, 602 CHAPTER 10 Sexuality-Reproductive Pattern 611 PATTERN DESCRIPTION, 611 PATTERN ASSESSMENT, 611 CONCEPTUAL INFORMATION, 611 DEVELOPMENTAL CONSIDERATIONS, 612 APPLICABLE NURSING DIAGNOSES, 614 Rape-Trauma Syndrome: Compound Reaction and Silent Reaction, 614 Copyright © 2002 F.A. Davis Company CONTENTS xv Sexual Dysfunction, 621 Sexuality Patterns, Ineffective, 628 CHAPTER 11 Coping–Stress Tolerance Pattern 633 PATTERN DESCRIPTION, 633 PATTERN ASSESSMENT, 633 CONCEPTUAL INFORMATION, 634 DEVELOPMENTAL CONSIDERATIONS, 635 APPLICABLE NURSING DIAGNOSES, 637 Adjustment, Impaired, 637 Community Coping, Ineffective and Readiness for Enhanced, 645 Family Coping, Compromised and Disabled, 650 Family Coping, Readiness for Enhanced, 657 Individual Coping, Ineffective, 661 Post-Trauma Syndrome, Risk for and Actual, 670 Suicide, Risk for, 676 CHAPTER 12 Value-Belief Pattern 681 PATTERN DESCRIPTION, 681 PATTERN ASSESSMENT, 681 CONCEPTUAL INFORMATION, 681 DEVELOPMENTAL CONSIDERATIONS, 682 APPLICABLE NURSING DIAGNOSES, 683 Spiritual Distress, Risk for and Actual, 683 Spiritual Well-Being, Readiness for Enhanced, 689 Appendix A: NANDA’s Descriptors (Axis 6), 693 Appendix B: Admission Assessment Form and Sample, 694 References, 721 Index, 733 Copyright © 2002 F.A. Davis Company CHAPTER 1 Introduction Why This Book? (NANDA),* we believe this book makes it easier for you, the stu- dent, to learn and use nursing diagnosis in planning care for your When the first edition of this book was written, all the authors were patients. faculty members at the same school of nursing. We had become frustrated with the books that were available for teaching nursing The Nursing Process diagnosis to students and found that the students were also ex- pressing some of the same frustration. PURPOSE The students felt they needed to bring several books to the clin- ical area because the books for nursing diagnosis had limited in- Gordon1 indicates that Lydia Hall was one of the first nurses to use formation on pathophysiology and psychosocial or developmental the term nursing process in the early 1950s. Since that time, the term factors that had an impact on individualized care planning. The stu- nursing process has been used to describe the accepted method of de- dents were also confused regarding the different definitions, defin- livering nursing care. Iyer and coauthors2 state, “The major purpose ing characteristics, and related factors each of the authors used. The of the nursing process is to provide a framework within which the in- students were having difficulty writing individualized nursing ac- dividualized needs of the client, family, and community can be met.” tions for their patients because the various authors appeared to fo- It may be easier to think of a framework as a blueprint or an out- cus on specifics related to the etiology or signs and symptoms of the line that guides the planning of care for a patient.† As Doenges and nursing diagnosis rather than the concept represented by the nurs- Moorhouse write,3 “The nursing process is central to nursing ac- ing diagnosis that had been emphasized to our students. The au- tions in any setting because it is an efficient method of organizing thors were also concerned about the number of books our students thought processes for clinical decision making and problem solv- had to buy, because most books focused on just one clinical area, ing.” Use of the nursing process framework is beneficial for both the such as adult health or pediatrics. Thus, as the students progressed patient and the nurse because it helps ensure that care is planned, through the school, they had to buy different books for different individualized, and reviewed over the period of time that the nurse clinical areas even though each of the books had the common and patient have a professional relationship. It must be emphasized theme of the use of nursing diagnosis. Another concern we, as fac- that the nursing process requires the involvement of the patient ulty, had was the lack of information in the various books regard- throughout all the phases. If the patient is not involved in all phases ing the final phase of the nursing process—evaluation. This most then the plan of care is not individualized. vital phase was briefly mentioned, but very little guidance was given in how to proceed through this phase. DEFINITION The final concern that led to the writing of the book was our desire to focus on nursing actions and nursing care, not medical Alfaro4 defines nursing process as “an organized, systematic method care and medical diagnosis. We strongly believe and support the of giving individualized nursing care that focuses on identifying and vital role of nurses in the provision of health care for our nation, treating unique responses of individuals or groups to actual or po- and so we have focused in this book strictly on nursing. After all, tential alterations in health.” This definition fits very nicely with the statistics show that the largest number of health care providers are American Nurses Association (ANA) Social Policy Statement5: “Nurs- nurses and that the general public has a high respect for nurses. ing is the diagnosis and treatment of human responses to actual and Therefore, let us work on developing our profession and its potential health problems.” Alfaro’s definition is further supported by contributions. the ANA Standards of Clinical Nursing Practice6 (Table 1–1), prac- For these reasons, we have written this book particularly geared tice standards written by several boards of nursing,7 and the defini- to student use. Specifically, we wrote this book to assist students tion of nursing that is written into the majority of nurse practice acts to learn how to apply nursing diagnosis

in the clinical area. By us- ing the framework of the nursing process and the materials gen- erated by the North American Nursing Diagnosis Association †Throughout this book we use the terms patient and client interchange- ably. In most instances these terms refer to the individual who is receiving *Nursing diagnoses developed by and used with permission of North nursing care; however, a patient can also be a community, such as in the American Nursing Diagnosis Association. NANDA Nursing Diagnoses: De- community–home health nursing actions, or the patient can be a family, finitions and Classification 2001–2002. NANDA, Philadelphia, 2001. such as for the nursing diagnosis Ineffective Family Coping, Compromised. 1 Copyright © 2002 F.A. Davis Company 2 INTRODUCTION We are now caring for patients on a general medical-surgical unit TABLE 1–1. STANDARDS OF CARE who would have been in a critical care unit 10 years ago. We are now sending patients home in 1 to 3 days who we would have kept in the Standard I. Assessment: The nurse collects patient health data. hospital another 5 to 10 days 10 years ago. Procedures that required Standard II. Diagnosis: The nurse analyzes the assessment data in a 3- to 5-day hospital stay in the past are now being performed in day determining diagnoses. surgery or outpatient facilities. A variety of factors have led to this sit- uation, including the advent of the use of diagnosis related groups Standard III. Outcome Identification: The nurse identifies expected outcomes individualized to the patient. (DRGs) for patient billing; managed care insurance plans; prospec- tive payment insurance plans; capitated payment insurance plans; Standard IV. Planning: The nurse develops a plan of care that pre- movement from acute care to longer term care settings such as home scribes interventions to attain expected outcomes. health, nursing homes, and rehabilitation units; and, most impor- Standard V. Implementation: The nurse implements the interven- tantly, the desire to contain the rapidly rising costs of health care. tions identified in the plan of care. These problems, which together have been labeled the “quicker, sicker” phenomenon, in combination with a national sporadic short- Standard VI. Evaluation: The nurse evaluates the patient’s progress age of registered nurses have created a situation in which contact time toward attainment of outcomes. with a patient is being cut to a minimum. If care planning is not done, given this set of circumstances, there is no doubt that gaps will exist Source: From American Nurses Association: Standards of Clinical Nursing in the nursing care given to a patient and that such care will be in- Practice. Author, Washington, DC, 1998, pp 7–10, with permission. complete, inconsistent, and certainly not of high quality. Second, care planning and its documentation provide a means of professional communication. This communication promotes con- in the United States. (The Standards of Nursing Practice of the Board sistency of care for the patient and provides a comfort level for the of Nurse Examiners for the State of Texas are used as an example. See nurse. Any patient admitted to a health care agency is going to have Table 1–2.) some level of anxiety. Imagine how this anxiety increases when Basically, the nursing process provides each nurse a framework each nurse who enters the room does each procedure differently, to utilize in working with the patient. The process begins at the time answers questions differently, or uses different time lines for care the patient needs assistance with health care through the time the (e.g., a surgical dressing that has been changed in the morning patient no longer needs assistance to meet health care maintenance. every day since surgery is not changed until the afternoon). Care The nursing process represents the cognitive (thinking and reason- planning provides a comfort level for the nurse because it gives the ing), psychomotor (physical), and affective (emotion and values) nurse a ready reference to help ensure that care is complete. Care skills and abilities used by the nurse to plan care for a patient. planning also provides a guideline for documentation and pro- motes practicing within legally defined standards. ROLE IN PLANNING CARE Third, care planning provides legal protection for the nurse. We are practicing in one of the most litigious societies that has ever existed. Perhaps the important question is why do we need to plan care? In the past, nurses were not frequently named in legal actions; how- There are several answers to this question that range from consid- ever, this has changed, as a brief review of suits being filed would erations of the individual needs of a patient to the legal aspects of show. In a legal suit, the nursing care is measured against the idea of nursing practice. what a reasonably prudent nurse would do in the same circumstances. First, the patient has a right to expect that the nursing care received The accepted standards of nursing practice, as published by ANA6 will be complete and of high quality. If care planning is not done, (see Table 1–1) and the individual boards of nursing7 (see Table 1–2), then gaps are going to exist in the patient’s care. At this time, patients are the accepted definitions of reasonable, prudent nursing care. are being admitted to the hospital more acutely ill than in the past. Finally, accrediting and approval agencies such as the Joint Com- mission on Accreditation of Healthcare Organizations ( JCAHO), the National League for Nursing Accrediting Commission (NLNAC), Medicare, and Medicaid have criteria that specifically require docu- TABLE 1–2. STANDARDS OF NURSING PRACTICE mentation of planning of care. The accreditation status of a health The registered nurse shall: care agency can depend on consistent documentation that planning 1. Know and conform to the Texas Nurse Practice Act and the of care has been done. Particularly with the third-party payers, such board’s rules and regulations as well as all federal, state, or local as Medicare, Medicaid, and insurance companies, lack of documen- laws, rules, or regulations affecting the RN’s current area of nurs- tation regarding the planning and implementation of care results in ing practice; no reimbursement for care. Ultimately, nonreimbursement for care 2. Use a systematic approach to provide individualized, goal- leads to lack of new equipment, no pay raises, and, in some extreme directed nursing care by: cases, has led to hospital closures. a. Performing nursing assessments regarding the health status of the client; CARE PLAN VERSUS PLANNING OF CARE b. Making nursing diagnoses that serve as the basis for the strat- egy of care; Revisions of nursing standards by JCAHO created questions re- c. Developing a plan of care based on the assessment and nurs- garding the necessity of nursing care plans. Some have predicted ing diagnosis; the rapid demise of the care plan, according to Brider,8 but review d. Implementing nursing care; and of the revised nursing standards shows that the standards require e. Evaluating the client’s responses to nursing interventions. not less but more detailed care planning documentation in the pa- tient’s medical record. Source: Adapted from Board of Nurse Examiners for the State of Texas: Review of the new criteria indicates that the standards require Standards of Nursing Practice. Texas Nurse Practice Act. Author, Austin, documentation related to the nursing process. For example, the TX, 1999, pp 13–15, with permission. JCAHO9 plan of care statement reads: Copyright © 2002 F.A. Davis Company NURSING PROCESS STEPS 3 A plan, based on data gathering during patient assessment, that iden- happening. An example of subjective data is the patient’s statement, tifies the patient’s care needs, tests the strategy for providing services “The pain begins in my lower back and runs down my left leg.” to meet those needs, documents treatment goals or objectives, out- Objective data are those facts that are observable and measurable lines the criteria for terminating specified interventions, and docu- by the nurse. These data are gathered by the nurse through physi- ments the individual’s progress in meeting specified goals and objec- cal assessment, interviewing, and observing and involve the use of tives. The format of the “plan” in some organizations may be guided the senses of seeing, hearing, smelling, and touching. An example by patient-specific policies and procedures, protocols, practice guide- of objective data is the measurement and recording of vital signs. lines, clinical paths, care maps, or a combination of these. The plan Objective data are also gathered through such diagnostic examina- of care may include care, treatment, habilitation and rehabilitation. tions as laboratory tests, x-ray examinations, and other diagnostic Rather than eliminating care plans, the JCAHO requirements call procedures. for a more specific as well as a more permanent documentation of Historical data are those health events that happened prior to this the plan of care. This documentation must be in the medical record. admission or health problem episode. An example of historical data The standard indicates that a separate care plan form is no longer is the patient statement, “The last time I was in a hospital was 1996 necessary; however, the standard also still allows a separate care when I had an emergency appendectomy.” plan form. Various institutions are now testing flexible ways of doc- Current data are those facts specifically related to this admission umenting care planning. The care plan is not dead; rather, it is re- or health problem episode. An example of this type of data is vital vised to more clearly reflect the important role of nursing in the pa- signs on admission: T 99.2F, P 78, R 18, BP 134/86. Please note, tient’s care. No longer a separate, often discarded, and irrelevant that just as there is overlapping of the nursing process steps, there page, the plan of care must be part of the permanent record. The is also overlapping of the data types. Both historical and current flow sheets developed for this book offer guidelines for computer- data may be either subjective or objective. Historical and current izing information regarding nursing care. data assist in establishing time references and can give an indica- Faculty can use the revised JCAHO standards to assist students tion of the patient’s usual functioning. in developing expertise beyond writing extensive nursing care plans. This additional expertise requires the new graduate to inte- Essential Skills grate all phases of the nursing process into the permanent record. Rather than eliminating the need for care planning and nursing di- Assessment requires the use of the skills needed for interviewing, agnosis, the standards have reinforced the importance of nursing conducting a physical examination, and observing. As with the care and nursing diagnosis. nursing process itself, these skills are not used one at a time. While you are interviewing the patient, you are also observing and deter- mining physical areas that require a detailed physical assessment. Nursing Process Steps While completing a physical assessment, you are asking questions (interviewing) and observing the patient’s physical appearance as There are five steps, or phases, in the nursing process: assessment, well as the patient’s response to the physical examination. diagnosis, planning, implementation, and evaluation. These steps Interviewing generally starts with gathering data for the nursing are not discrete steps, but rather, they overlap and build on each history. In this interview, you ask for general demographic infor- other. To carry out the entire nursing process, you must be sure to mation such as name, address, date of last hospitalization, age, al- accurately complete each step and then build upon the information lergies, current medications, and the reason the patient was admit- in that step to complete the next step. ted. Depending on the agency’s admission form, you may then progress to other specific questions or a physical assessment. An ex- ASSESSMENT ample of an admission assessment specifically related to the Func- The first step, or phase, of the nursing process is assessment. During tional Health Patterns is given in Appendix B. this phase you are collecting data (factual information) from several The physical assessment calls for four skills: inspection, palpa- sources. The collection and organization of these data allow you to: tion, percussion, and auscultation. Inspection means careful and systematic observation throughout the physical examination, such 1. Determine the patient’s current health status. as observation for and recording of any skin lesions. Palpation is as- 2. Determine the patient’s strengths and problem areas (both ac- sessment by feeling and touching.

Assessing the differences in tem- tual and potential). perature between a patient’s upper and lower arm would be an ex- 3. Prepare for the second step of the process—diagnosis. ample of palpation. Another common example of palpation is breast self-examination. Percussion involves touching, tapping, and Data Sources and Types listening. Percussion allows determination of the size, density, lo- cations, and boundaries of the organs. Percussion is usually per- The sources for data collection are numerous, but it is essential to formed by placing the index or middle finger of one hand firmly on remember that the patient is the primary data source. No one else the skin and striking with the middle finger of the other hand. The can explain as accurately as the patient the start of the problem, the resultant sound is dull if the body is solid under the fingers (such reason for seeking assistance or the exact nature of the problem, as at the location of the liver) and hollow if there is a body cavity and the effect of the problem on the patient. Other sources include under the finger (such as at the location of the abdominal cavity). the patient’s family or significant others; the patient’s admission Auscultation involves listening with a stethoscope and is used to sheet from the admitting office; the physician’s history, physical, help assess respiratory, circulatory, and gastrointestinal status. and orders; laboratory and x-ray results; information from other The physical assessment may be performed using a head-to-toe caregivers; and current nursing literature. approach, a body system approach, or a functional health pattern Assessment data can be further classified as types of data. Ac- approach. In the head-to-toe approach, you begin with the patient’s cording to Iyer and associates,2 the data types are subjective, ob- general appearance and vital signs. You then progress, as the name jective, historical, and current. indicates, from the head to the extremities. Subjective data are the facts presented by the patient that show his The body system approach to physical assessment focuses on the or her perception, understanding, and interpretation of what is major body systems. As the nurse is conducting the nursing history Copyright © 2002 F.A. Davis Company 4 INTRODUCTION interview, she or he will get a firm idea of which body systems need processes. Nursing diagnoses provide the basis for selection of nurs- detailed examination. An example is a cardiovascular examination, ing interventions to achieve outcomes for which the nurse is ac- where the apical and radial pulses, blood pressure (BP), point of countable. maximum intensity (PMI), heart sounds, and peripheral pulses are examined. Much debate occurred during the Ninth Conference regarding this The functional health pattern approach is based on Gordon’s Func- definition, and it is anticipated this debate will continue. The de- tional Health Patterns typology and allows the collection of all types bate centers on a multitude of issues related to the definition, which of data according to each pattern. This is the approach used by this are beyond the scope of this book. Readers are urged to consult the book and leads to three levels of assessment. First is the overall ad- official journal of NANDA, Nursing Diagnosis: The International Jour- mission assessment, where each pattern is assessed through the col- nal of Nursing Language and Classification, to keep up to date on this lection of objective and subjective data. This assessment indicates debate. patterns that need further attention, which requires implementa- The definition of nursing diagnosis distinguishes nursing diag- tion of the second level of pattern assessment. The second level of nosis from medical diagnosis. For example, nursing diagnosis is dif- pattern assessment indicates which nursing diagnoses within the ferent from medical diagnosis in its focus. Kozier, Erb, and pattern might be pertinent to this patient, which leads to the third Olivieri11 write that nursing diagnoses focus on patient response, level of assessment, the defining characteristics for each individual whereas medical diagnoses focus on the disease process. As indi- nursing diagnosis. Having a three-tiered assessment might seem cated by the definition of nursing diagnosis, nurses also identify po- complicated, but each assessment is so closely related that comple- tential problems; physicians place primary emphasis on identifying tion of the assessment is easy. A primary advantage in using this the current problem. type of assessment is the validation it gives to the nurse that the re- Nursing diagnosis and medical diagnosis are similar in that the sulting nursing diagnosis is the most correct diagnosis. Another same basic procedures are used to derive the diagnosis (i.e., phys- benefit to using this type of assessment is that grouping of data is ical assessment, interviewing, and observing). Likewise, according already accomplished and does not have to be a separate step. to Kozier and associates,11 both types of diagnoses are designed for essentially the same reason—planning care for a patient. A nursing diagnosis is based on the presence of defining charac- Data Grouping teristics. According to NANDA,12 defining characteristics are clini- cal criteria that represent the presence of the diagnostic category Data grouping simply means organizing the information into sets or (nursing diagnosis). For actual nursing diagnoses (the problem is categories that will assist you in identifying the patient’s strengths present), a majority of the defining characteristics must be present. and problem areas. A variety of organizing frameworks is available, For risk diagnoses (risk factors indicate the problem might de- such as Maslow’s Hierarchy of Needs, Roy’s Adaptation Model, and velop), the risk factors must be present. Gordon’s Functional Health Patterns. Each of the nursing theorists (e.g., Roy, Levine, and Orem) speaks to assessment within the framework of their theories. Diagnostic Statements Organizing the information allows you to identify the appropri- ate functional health pattern and also allows you to spot any miss- According to the literature, complete nursing diagnostic statements ing data. If you cannot identify the pertinent functional health pat- include, at a minimum, the human response and an indication of tern, then you need to collect further data. The goal of data the factors contributing to the response. The following is a rationale grouping is to arrive at a nursing diagnosis. for the two-part statement13: Each nursing diagnosis, when correctly written, can accomplish DIAGNOSIS two things. One, by identifying the unhealthy response, it tells you what should change. . . . And two, by identifying the probable cause Diagnosis means reaching a definite conclusion regarding the pa- of the unhealthy response, it tells you what to do to effect change. tient’s strengths and problems. The problems are the primary focus for planning care, and the strengths are used to assist you in im- Although there is no consensus on the phrase that should be used plementing this care. In this book, we concentrate the diagnosis to link the response and etiologic factors, perusal of current litera- phase of the nursing process on nursing diagnosis and use the di- ture indicates that the most commonly used phrases are related to, agnoses accepted by NANDA for testing. secondary to, and due to. The phrase related to is gaining the most acceptance because it does not imply a direct cause-and-effect relationship. Kieffer14 be- Nursing Diagnosis lieves using the phrases due to and secondary to may reflect such a The North American Nursing Diagnosis Association (NANDA), cause-and-effect relationship, which could be hard to prove. Thus, formerly the National Conference Group for Classification of Nurs- a complete nursing diagnostic statement would read: Pain related ing Diagnosis, has been meeting since 1973 to identify, develop, to surgical incision. and classify nursing diagnoses. Setting forth a nursing diagnosis Gordon1 identifies three structural components of a nursing di- nomenclature articulates nursing language, thus promoting the agnostic statement: The problem (P), the etiology (E), and signs and identification of nursing’s contribution to health, and facilitates symptoms (S). The problem describes the patient’s response or cur- communication among nurses. In addition, the use of nursing di- rent state (the nursing diagnosis); the etiology describes the cause or agnosis provides a clear distinction between nursing diagnosis and causes of the response (related to); and the symptoms delineate the medical diagnosis and provides clear direction for the remaining as- defining characteristics or observable signs and symptoms demon- pects of the planning of care. strated or described by the patient. The S component can be read- NANDA accepted its first working definition of nursing diagno- ily connected to the P and E statements through the use of the sis in 199010: phrase as evidenced by. Using this format, a complete nursing diag- nostic statement would read: Pain related to surgical incision as ev- A nursing diagnosis is a clinical judgment about individual, family idenced by verbal comments and body posture. or community responses to actual or potential health problems/life As discussed in the preface, we recommend starting with stating Copyright © 2002 F.A. Davis Company NURSING PROCESS STEPS 5 the nursing diagnosis only. Therefore, the nursing diagnosis would Expected Outcomes be listed in the patient’s chart in the same manner as it is given in the nomenclature: Pain. Remember that the objective and subjective data Outcomes, goals, and objectives are terms that are frequently used in- related to the patient’s pain have already been recorded in the health terchangeably because all indicate the end point we will use to mea- record in the assessment section, so there is no need to repeat it. sure the effectiveness of our plan of care. Because so many pub- The nursing diagnostic statement examples given previously de- lished sets of standards and JCAHO talk in terms of outcome scribe the existence of an actual problem. Professional nurses are standards or criteria, we have chosen to use the term “expected out- strong supporters of preventive health care—cases in which a prob- comes” in this book. lem does not yet exist and measures that can be taken to ensure that Several authors11,15,16 give guidelines for writing clinically useful the problem does not arise. In such instances, the nursing diagnos- expected outcomes: tic statement is prefaced by the words “Risk for.” Nursing diagnoses 1. Expected outcomes are clearly stated in terms of patient behav- that carry the preface “Risk for” also carry with them risk factors ior or observable assessment factors. rather than defining characteristics. Whereas other books include a variety of nursing diagnoses, this EXAMPLE book uses only the actual and risk (formerly labeled “potential”) di- POOR Will increase fluid balance by time of discharge. agnoses accepted by NANDA for testing. Probable related factors GOOD Will increase oral fluid intake to 1500 mL per 24 (formerly “etiologic factors”) are grouped, as are the defining char- hours by 9/11. acteristics (formerly “signs and symptoms”), under each specific nursing diagnosis. As indicated in the preface, nursing actions in 2. Expected outcomes are realistic, achievable, safe, and acceptable this book reflect a conceptual approach rather than a specific (to re- from the patient’s viewpoint. lated factors or defining characteristics) approach. EXAMPLE To illustrate this approach, let us use the diagnosis Pain. There Mrs. Braxton is a 28-year-old woman who has delayed healing of are common nursing orders related to the incidence of pain re- a surgical wound. She is to receive discharge instructions regard- gardless of whether the pain is caused by surgery, labor, or trauma. ing a high-protein diet. She is a widow with three children younger You can take this conceptual approach and make an individualized than the age of 10. Her only source of income is Social Security. adaptation according to the etiologic factors affecting your patient POOR Will eat at least two 8-oz servings of steak daily. [un- and the reaction your patient is exhibiting to pain. realistic, nonachievable, unacceptable, etc.] Identifying and specifying the nursing diagnoses leads to the next GOOD Will eat at least two servings from the following list phase of the process—planning. Now that you know what the each day: problems and strengths are, you can decide how to resolve the Lean ground meat problem areas while building on the strength areas. Eggs Cheese PLANNING Pinto beans Peanut butter Planning involves three subsets: setting priorities, writing expected Fish outcomes, and establishing target dates. Planning sets the stage for Chicken writing nursing actions by establishing where we are going with our plan of care. Planning further assists in the final phase of evaluation

3. Expected outcomes are written in specific, concrete terms de- by defining the standard against which we will measure progress. picting patient action. Setting Priorities EXAMPLE POOR Maintains fluid intake by 9/11. With the sicker, quicker problem discussed earlier, you are going GOOD Will drink at least 8-oz of fluid every hour from 7 a.m. to find yourself in the situation of having identified many more to 10 p.m. by 9/11. problems than can possibly be resolved in a 1- to 3-day hospital- ization (today’s average length of stay). In the long-term care facil- 4. Expected outcomes are directly observable by use of at least one ities, such as home health, rehabilitation, and nursing homes, long- of the five senses. range problem solving is possible, but setting priorities of care is EXAMPLE still necessary. POOR Understands how to self-administer insulin by 9/11. Several methods of assigning priorities are available. Some GOOD Accurately return-demonstrates self-administration of nurses assign priorities based on the life threat posed by a problem. insulin by 9/11. For example, Ineffective Airway Clearance would pose more of a threat to life than the diagnosis Risk for Impaired Skin Integrity. 5. Expected outcomes are patient centered rather than nurse Some nurses base their prioritization on Maslow’s Hierarchy of centered. Needs. In this instance, physiologic needs would require attention EXAMPLE before social needs. One way to establish priorities is to simply ask POOR Teaches how to measure blood pressure by 9/11. the patient which problem he or she would like to pay attention to GOOD Accurately measures own blood pressure by 9/11. first. Another way to establish priorities is to analyze the relation- ships between problems. For example, a patient has been admitted with a medical diagnosis of headaches and possible brain tumor. Establishing Target Dates The patient exhibits the defining characteristics of both Pain and Writing a target date at the end of the expected outcome statement Anxiety. In this instance, we might want to implement nursing ac- facilitates the plan of care in several ways11,15: tions to reduce anxiety, knowing that if the anxiety is not reduced, pain control actions will not be successful. Once priorities have 1. Assists in “pacing” the care plan. Pacing helps keep the focus on been established, you are ready to establish expected outcomes. the patient’s progress. Copyright © 2002 F.A. Davis Company 6 INTRODUCTION 2. Serves to motivate both patients and nurses toward accomplish- any other health care practitioner, for example, deciding which ing the expected outcome. noninvasive technique to use for pain control or deciding when to 3. Helps patient and nurse see accomplishments. teach the patient self-care measures. Collaborative actions are those 4. Alerts nurse when to evaluate care plan. activities that involve mutual decision making between two or more health care practitioners, for example, a physician and nurse de- Target dates can be realistically established by paying attention ciding which narcotic to use when meperidine is ineffective in con- to the usual progress and prognosis connected with the patient’s trolling the patient’s pain, or a physical therapist and nurse decid- medical and nursing diagnoses. Additional review of the data col- ing on the most beneficial exercise program for a patient. lected during the initial assessment helps indicate individual factors Implementing a physician’s order and referral to a dietitian are to be considered in establishing the date. For example, one of the other common examples of collaborative actions. previous expected outcomes was stated as “Accurately return- Written nursing actions guide both actual patient care and demonstrates self-administration of insulin by 9/11.” proper documentation, and they must therefore be detailed and ex- The progress or prognosis according to the patient’s medical and act. Written nursing actions should be even more definite than nursing diagnosis will not be highly significant. The primary factor what is generally found in physician orders. For example, a physi- will be whether diabetes mellitus is a new diagnosis for the patient cian writes the order, “Increase ambulation as tolerated” for a pa- or is a recurring problem for a patient who has had diabetes melli- tient who has been immobile for 2 weeks. The nursing actions tus for several years. should reflect specified increments of ambulation as well as ongo- For the newly diagnosed patient, we would probably want our ing assessment: deadline day to be 5 to 7 days from the date of learning the diag- nosis. For the recurring problem, we might establish the target date to be 2 to 3 days from the date of diagnosis. The difference is, of course, the patient’s knowledge base. 11/2 1.a. Prior to activity, assess BP, P, and R. After activity assess: Now look at an example related to the progress issue. Mr. Kit is (1) BP, P, R; (2) presence/absence of vertigo; (3) circula- a 19-year-old college student who was admitted early this morning tion; (4) presence/absence of pain. with a medical diagnosis of acute appendicitis. He has just returned b. Assist to dangle on bedside for 15 minutes at least 4 from surgery following an appendectomy. One of the nursing di- times a day on 11/2. agnoses for Mr. Kit would, in all probability, be Pain. The expected c. If BP, P, or R change significantly or vertigo is present outcome could be “Will have decrease in number of requests for or circulation is impaired or pain is present, return to supine position immediately. Elevate head of bed 30 analgesics by [date].” In reviewing the general progress of a young degrees for 1 hour; then 45 degrees for 1 hour; then 90 patient with this medical and nursing diagnosis, we know that gen- degrees for 1 hour. If tolerated with no untoward signs erally analgesic requirements start decreasing within 48 to 72 or symptoms, initiate order 1b again. hours. Therefore, we would want to establish our target date as 2 d. Assist up to chair at bedside for 30 minutes at least 4 to 3 days following the day of surgery. This would result in the ob- times a day on 11/3. jective reading (assume date of surgery was 11/1): “Will have de- e. Assist to ambulate to bathroom and back at least 4 times crease in number of requests for analgesics by 11/3.” a day on 11/4. To further emphasize the target date, it is suggested that the date f. Supervise ambulation of one-half length of hall at least 4 be underlined, highlighted by using a different-colored pen, or cir- times a day on 11/5 and 11/6. cled to make it stand out. Pinpointing the date in such a manner g. Supervise ambulation of length of hall at least 4 times a emphasizes that evaluation of progress toward achievement of the day on 11/7. expected outcome should be made on that date. In assigning the S. J. Smith, RN dates, be sure not to schedule all the diagnoses and expected out- comes for evaluation on the same date. Such scheduling would re- quire a total revision of the plan of care, which could contribute to Nursing actions further differ from physician orders in that the not keeping the plan of care current. Being able to revise single por- patient’s response is directly related to the implementation of tions of the plan of care facilitates use and updating of the plan. Re- the action. It is rare to see a physician order that includes alter- member that the target date does not mean the expected outcome natives if the first order has minimal, negative, or no effect on the must be totally achieved by that time; instead, the target date sig- patient. nifies the evaluation date. A complete written nursing action incorporates at least the fol- Once expected outcomes have been written, you are then ready lowing five components according to Bolander15: to focus on the next phase—implementation. As previously indi- cated, the title supported by this book for this section is “Nursing 1. Date the action was initially written Actions.” 2. A specific action verb that tells what the nurse is going to do (e.g., “assist” or “supervise”) 3. A prescribed activity (e.g., ambulation) IMPLEMENTATION 4. Specific time units (e.g., for 15 minutes at least 4 times a day) Implementation is the action phase of the nursing process; hence, we 5. Signature of the nurse who writes the initial action order (i.e., chose the term “nursing actions.” Two important steps are involved accepting legal and ethical accountability) in implementation: The first is determining the specific nursing ac- A nursing action should not be implemented unless all five com- tions that will assist the patient to progress toward the expected out- ponents are present. A nurse would not administer a medication if come, and the second is documenting the care administered. the physician order read, “Give Demerol”; neither should a nurse Nursing action is defined as nursing behavior that serves to help be expected to implement a nursing action that reads, “Increase am- the patient achieve the expected outcome. Nursing actions include bulation gradually.” both independent and collaborative activities. Independent actions Additional criteria that should be remembered to ensure com- are those activities the nurse performs using his or her own discre- plete, quality nursing action, include: tionary judgment and that require no validation or guidelines from Copyright © 2002 F.A. Davis Company NURSING PROCESS STEPS 7 1. Consistency between the prescribed actions, the nursing diag- supine position with head of bed elevated to 30- nosis, and expected outcome (including numbering). degree angle. BP 100/68, P 80, R 24. 1100 BP 122/74, P 76, R 18. No complaints of vertigo or EXAMPLE nausea. Head of bed elevated to 45-degree angle. Nursing Diagnosis 1: Impaired physical mobility, level 2. Expected Outcome 1: Will ambulate length of hall by 11/8. Writing nursing actions in such a manner automatically leads to Nursing Action 1: reflection of the quality of care planning in the chart. Documenta- tion of care planning in the patient’s chart is essential to meet na- tional standards of care and criteria for agency accreditation. 11/2 1.a. Prior to activity, assess BP, P, and R. After activity assess: (1) BP, P, R; (2) presence/absence of vertigo; (3) circula- DOCUMENTATION tion; (4) presence/absence of pain. Just as development of the nursing process as a framework for prac- b. Assist to dangle on bedside for 15 minutes at least 4 times a day on 11/2. tice has evolved, so documentation of that process has become an c. If BP, P, or R changes significantly or vertigo is present essential link between the provision of nursing care and the qual- or circulation is impaired or pain is present, return to ity of the care provided. Several nursing documentation systems supine position immediately. Elevate head of bed 30 de- have emerged that make it easier to document the nursing process. grees for 1 hour; then 45 degrees for 1 hour; then 90 de- Four of these systems are discussed here. You will note that the nar- grees for 1 hour. If tolerated with no untoward signs or rative system is not discussed, because it tends to be fragmented symptoms, initiate action 1b again. and disjointed and presents problems in retrieval of pertinent in- d. Assist up to chair at bedside for 30 minutes at least 4 formation about the patient response to and outcomes of nursing times a day on 11/3. care. e. Assist to ambulate to bathroom and back at least 4 times The Problem Oriented Record (POR) with its format for docu- a day on 11/4. menting progress notes provides a system for documenting the f. Supervise ambulation of one-half length of hall at least 4 nursing process. Additionally, POR is an interdisciplinary docu- times a day on 11/5 and 11/6. mentation system that can be used to coordinate care for all health g. Supervise ambulation of length of hall at least 4 times a care providers working with the patient. day on 11/7. The POR consists of four major components: S. J. Smith, RN 1. The database 2. The problem list 2. Consideration of both patient and facility resources. It would be 3. The plan of care senseless to make referrals to physical and occupational therapy 4. The progress notes services if these were not available. Likewise, from the patient’s The database is that information that

has been collected through resource viewpoint, it would be foolish to teach a patient and his patient interview, observation, and physical assessment and the re- or her family how to manage care in a hospital bed if this bed sults of diagnostic tests. The database provides the basis for devel- would not be available to the patient at home. oping the problem list. 3. Careful scheduling to include the patient’s significant others and The problem list is an inventory of numbered, prioritized patient to incorporate usual activities of daily living (i.e., rest, meals, problems. Patient problems may be written as nursing or medical sleep, and recreation). diagnoses. Problems may be actual or risk diagnoses. Because each 4. Incorporation of patient teaching and discharge planning from problem is numbered, information about each problem is easily the first day of care. retrieved. 5. Individualization and updating in keeping with the patient’s The plan of care incorporates the expected outcomes, target condition and progress. dates, and prescribed nursing actions as well as other interven- tions designed to resolve the problem. The plan of care reflects Including the key components and validating the quality of multidisciplinary care and should be agreed to by the health care the written nursing actions help promote improved documenta- team. tion. In essence, the written nursing actions can give an outline for The progress note provides information about the patient’s re- documentation. sponse to or outcomes of the care provided. The full format for doc- Properly written nursing actions demonstrate to the nurse both umenting progress is based on the acronym SOAPIER, which stands nursing actions and documentation to be done. Referring to the for Subjective data, Objective data, Analysis/assessment, Plan, Inter- preceding example, we can see that the nurse responsible for vention, Evaluation, and Revision. As the plan of care is implemented this patient’s care should chart the patient’s blood pressure (BP), for each numbered, prioritized problem, it is documented using the pulse (P), and respiration (R) rates prior to the activity, the pa- SOAPIER format. For example, recall the case of Mr. Kit, the 19- tient’s BP, P, and R rates after the activity, the presence or absence year-old college student who is recovering from an appendectomy. of vertigo, the presence or absence of pain, and the results of a The problem list inventory would probably show Problem #1: Pain. circulatory check. Additionally, the nurse knows to chart that His plan of care would state as an expected outcome: “Will have de- the patient dangled, sat up, or ambulated for a certain length of crease in number of requests for analgesics by 11/3.” Some of the time or distance. Further, the nurse has guidelines of what to written nursing actions would read: do and chart if an untoward reaction occurs in initial attempts at ambulation. 1. Monitor for pain at least every 2 hours and have patient rank pain on a scale of 0–10. EXAMPLE 2. Administer pain medications as ordered. Monitor response. 1000 BP 132/82, P 74, R 16. Up on side of bed for 5 min- 3. Spend at least 30 minutes once a shift teaching patient deep utes. Complained of vertigo and nausea. Returned to muscle relaxation. Talk patient through relaxation every 4 Copyright © 2002 F.A. Davis Company 8 INTRODUCTION hours, while awake, at [list times here] once initial teaching is done. DATE/TIME SIGNATURE FOCUS PATIENT CARE NOTE The progress note of 11/3 would appear as follows: 11/1 1500 Pain D C/o pain, “My side hurts. It is a 9 on J. Jones, RN a 0–10 scale.” BP 130/84, P 88, R 22. 11/1 1530 A Demerol 100 mg given in rt gluteus. PROBLEM 1 J. Jones, RN Turned to left side. Back rub given. 11/1 1615 R States pain is better. Rates it 2 on a S “I have had only one pain medication during J. Jones, RN 0–10 scale. BP 120/80, P 82, R 18. the last 24 hours, and that relieved my pain.” “I would rank my pain as a 1 on a scale of 0–10.” FOCUS charting provides a succinct system for documenting the O Relaxation exercises taught, and return- nursing process. It reflects all the elements required by JCAHO. It demonstration completed on 11/2. No request is flexible, provides cues to documentation with its DAR format, for pain medication within past 12 hours. and makes it easy to retrieve pertinent data. For more information A Pain relieved. on FOCUS, use the information written by Lampe.18 P None. The PIE documentation system emphasizes the nursing process I None. and nursing diagnosis. PIE is the acronym for Problem, Intervention, E Expected outcome met. Problem resolved. and Evaluation. A timesaving aspect of this system is that PIE does Discontinue problem. not require a separate plan of care. The initial database and ongo- R None. ing assessments are recorded on special forms or flow sheets. As- sessment data are not included in the progress note unless a change in the patient’s condition occurs. If a change occurs, “A” for assess- The POR with its SOAPIER progress note emphasizes the problem- ment would be recorded in the progress note. Routine interven- solving component within the nursing process and provides docu- tions are recorded on a flow sheet, and the progress note is used for mentation of the care provided. For further information about the specific numbered problems. POR system, you are directed to the Weed17 reference. When a problem is identified, it is entered into the progress note FOCUS charting, which is actually an offshoot of POR, is a docu- as a nursing diagnosis. Each problem is numbered consecutively mentation system that uses the nursing process to document care. during a 24-hour period, for example, P#1 and P#2. Therefore, the Unlike the interdisciplinary POR, FOCUS charting is entirely ori- nurse may refer to the number rather than having to restate the ented to nursing documentation. Like the POR system, FOCUS problem. Interventions (I), directed to the problem are docu- charting has a database, a problem list (FOCUS), a plan of care, and mented relative to the problem number (e.g., IP#1 or IP#2). Eval- progress notes. However, the FOCUS (problem list) is broader than uation (E) reflects patient response to or outcomes of nursing in- POR. In addition to nursing and medical diagnoses, the FOCUS of tervention and is labeled according to the problem number (e.g., care may also be treatments, procedures, incidents, patient concerns, EP#1 or EP#2). To illustrate, again using Mr. Kit: changes in condition, or other significant events. The medical record incorporates the plan of care in a three-column format (in addition to date/signature) labeled “FOCUS,” “expected patient outcomes,” DATE TIME NURSE’S NOTES and “nursing interventions.” To illustrate, again with Mr. Kit: 11/1 1500 P#1 Pain. IP#1 BP 130/84, P 88, R 22. J. Jones, RN 11/1 1530 IP#1 Demerol 100 mg given IM in rt gluteus. DATE/ EXPECTED PATIENT NURSING Turned to left side. Back rub given. SIGNATURE FOCUS OUTCOME INTERVENTION J. Jones, RN 11/1 11/1 1615 EP#1 States pain relieved. Rates pain as 2 on a J. Jones, RN Pain Will have decrease Monitor for pain at 0–10 scale. BP 120/80, P 82, R 18. in number of least every 2 J. Jones, RN requests for hours. Have pt analgesics rate pain on by 11/3. 0–10 scale. Each problem is evaluated at least every 8 hours, and all prob- Administer pain lems are reviewed and summarized every 24 hours. Continuing med as ordered. problems with appropriate interventions and evaluation are Monitor response. renumbered and redocumented daily, thus promoting continuity Teach pt use of of care. When a problem is resolved, it no longer is documented. noninvasive pain The PIE documentation system reflects the nursing process and sim- relief techniques plifies documentation by integrating the plan of care into the progress as appropriate. notes. This saves time and promotes easy retrieval of pertinent data. Siegrist, Deltor, and Stocks19 are the originators of the PIE System. Charting by Exception was developed by nurses at Saint Luke’s The progress notes incorporate a flow sheet for documenting daily Hospital in Milwaukee, Wisconsin.20 Documenting in this system interventions and treatments and a narrative progress note using a differs significantly from traditional systems in that nurses chart three-column format. The three-column format for the progress note only significant findings or exceptions to a predetermined norm. includes a column for date, time, and signature; a FOCUS column; This system centers on the development of clinical standards that and a patient care note column. When the progress note is written in describe accepted norms. The system makes extensive use of flow the patient care note column, it is organized using the acronym sheets and is becoming increasingly popular because of its stream- DAR—Data, Action, and Response. To illustrate, again using Mr. Kit: lined format and cost-effectiveness. Copyright © 2002 F.A. Davis Company NURSING PROCESS AND CONCEPTUAL FRAMEWORKS 9 A patient care plan is established based on described standards. has been met. The nurse documents the data collected and records Nursing actions are used as the base for documentation. Flow the judgment—“Resolved.” To illustrate, let us return to Mr. Kit. sheets are used to highlight significant findings and define assess- The nurse first reviews the chart. She finds that Mr. Kit requested ment parameters and findings. For example, for the postpartum pa- pain medication every 3 to 4 hours for the first 18 hours after tient, the standard for the cardiovascular assessment is: surgery. The nurses taught Mr. Kit relaxation exercises and turned him, positioned him, and gave him a backrub immediately after the Cardiovascular assessment: Apical pulse, CRT, peripheral administration of each analgesic. Mr. Kit has requested only one pulses, edema, calf tenderness. analgesic in the past 24 hours and none in the past 12 hours. He Standard: Regular apical pulse, CRT  3 s, peripheral pulses can return-demonstrate relaxation exercises and states he has only palpable, no edema, no calf tenderness, nailbeds and mucous a mild “twinge” when he gets out of bed. He is looking forward to membranes pink. returning to school next week. If the assessment findings were the same as the standard, the The nurse returns to the patient’s chart and records the follow- nurse simply makes a checkmark on the flow sheet by cardiovas- ing: “11/3 Data—1 analgesic in past 24 hours; none in past 12 cular assessment. If the assessment findings are different from the hours. Ambulates without pain; states having no pain. Resolved.” standard, the nurse marks an asterisk by cardiovascular assessment She then will draw one line through the nursing diagnosis, related and explains the deviation from the standard in the narrative notes. expected outcome(s), and nursing actions to show they have been Charting by Exception has been shown to reduce documentation discontinued. time and costs and increase attention to abnormal data. Addition- Revise can indicate two actions. In one instance, the initial nurs- ally, documentation is more consistent. ing diagnosis was not correct, so the diagnosis itself is revised. For More information about this system and examples of flow charts example, the nurse may have made an initial diagnosis of Self- can be found in the publication Charting by Exception.20 Esteem Disturbance. During collection of evaluation data, the pa- To complete the nursing process cycle and, depending on its out- tient and his family share further information that indicates that the come, perhaps start another cycle, the final phase of the process— more appropriate diagnosis is Powerlessness, Moderate. The plan evaluation—must be done. of care is then modified to reflect the change in the nursing diag- nosis. For evaluation purposes, the nurse again records the data and the word, “Revised.” She then adds the new nursing diagnosis and EVALUATION marks one line through the initial nursing diagnosis. Evaluation simply means assessing what progress has been made to- In the second instance, while the nurse is collecting evaluation ward meeting the expected outcomes; it is the most ignored phase data for one nursing diagnosis and expected outcome, she finds as- of the nursing process. The evaluation phase is the feedback and sessment factors that show another problem has arisen. She simply control part of the nursing process. Evaluation requires continua- records the appropriate judgment for the initial diagnosis and ex- tion of assessment that was begun in