Antistreptococcal, neuronal, and nuclear antibodies in Tourette syndrome

Immunity and Gilles de la Tourette syndrome: A systematic review and meta-analysis of evidence for immune implications in Tourette syndrome

BACKGROUND AND PURPOSE

The neurobiology of Gilles de la Tourette syndrome (GTS) is known to involve corticostriatal loops possibly under genetic control. Less is known about possible environmental triggers of GTS. Specifically, immune-related events following possible environmental inducers have been evoked, but important controversies still exist. In this systematic review and meta-analysis, we looked for evidence in favor of such possibilities.

METHODS

We performed a systematic review and meta-analysis of all immunological data in PubMed.

RESULTS

We found large discrepancies concerning immune dysfunctions in GTS, and meta-analyzing cytokines data did not allow us to conclude there is an involvement of specific cytokines in GTS neurobiology. When looking specifically at pediatric autoimmune neuropsychiatric disorder associated with streptococcus/pediatric acute onset neuropsychiatric syndrome, we found some important evidence of a possible infectious involvement but in a limited number of studies. Our meta-analysis found an increased level of anti-streptolysin O antibodies in GTS patients, but the level of anti-DNase B antibodies was not increased.

CONCLUSIONS

Too many questions still exist to allow us to definitively reach the conclusion that there is an infectious and immunological etiology in GTS. Much work is still needed to elucidate the possible role of immunology in GTS neurobiology and to favor immunological treatment rather than classical treatment.

Association of Group A Streptococcus Exposure and Exacerbations of Chronic Tic Disorders: A Multinational Prospective Cohort Study

OBJECTIVE

To examine prospectively the association between group A Streptococcus (GAS) pharyngeal exposures and exacerbations of tics in a large multicenter population of youth with chronic tic disorders (CTD) across Europe.

METHODS

We followed up 715 children with CTD (age 10.7 ± 2.8 years, 76.8% boys), recruited by 16 specialist clinics from 9 countries, and followed up for 16 months on average. Tic, obsessive-compulsive symptom (OCS), and attention-deficit/hyperactivity disorder (ADHD) severity was assessed during 4-monthly study visits and telephone interviews. GAS exposures were analyzed using 4 possible combinations of measures based on pharyngeal swab and serologic testing. The associations between GAS exposures and tic exacerbations or changes of tic, OC, and ADHD symptom severity were measured, respectively, using multivariate logistic regression plus multiple failure time analyses and mixed effects linear regression.

RESULTS

A total of 405 exacerbations occurred in 308 of 715 (43%) participants. The proportion of exacerbations temporally associated with GAS exposure ranged from 5.5% to 12.9%, depending on GAS exposure definition. We did not detect any significant association of any of the 4 GAS exposure definitions with tic exacerbations (odds ratios ranging between 1.006 and 1.235, all p values >0.3). GAS exposures were associated with longitudinal changes of hyperactivity-impulsivity symptom severity ranging from 17% to 21%, depending on GAS exposure definition.

CONCLUSIONS

This study does not support GAS exposures as contributing factors for tic exacerbations in children with CTD. Specific workup or active management of GAS infections is unlikely to help modify the course of tics in CTD and is therefore not recommended.

Tourette syndrome or PANDAS-a case report

Tourette syndrome (TS), a relatively common disorder, has been gaining more attention during the past two decades because of an increased number of reports. Nevertheless, it is still not completely understood. Furthermore, a clinical entity called "pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections" (PANDAS) has been introduced, which describes a tic disorder, accompanied by psychiatric disorders such as obsessive compulsive disorder (OCD), after a streptococcal infection in childhood. We present a case report of a 19-year-old adolescent Ukrainian female, with a history of anxiety disorder and OCD, who, despite TS remission during childhood, presented with new-onset motor and phonic tics after 1 month of severe tonsillitis. Blood and cerebrospinal cultures showed Streptococcus pyogenes, with magnetic resonance imaging revealing hypo-intense changes in the caudate nucleus on both sides. Treatment with clonazepam and fluoxetine, along with behavioral therapy, have improved the severity of her condition. This report presents a case of TS reemergence against the background of immunological reaction or PANDAS with a late adolescent onset.

Streptococcal Infections and Exacerbations in PANDAS: A Systematic Review and Meta-analysis

BACKGROUND

The pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) hypothesis suggests an association between group A beta-hemolytic streptococcus (GABHS) infections and subsequent onset or exacerbation of neuropsychiatric symptoms, such as obsessive-compulsive disorder or tic disorders.

METHODS

We performed a systematic review and meta-analysis including longitudinal, prospective studies on exacerbations of neuropsychiatric symptoms associated with GABHS infections in children with PANDAS. We searched PubMed and EMBASE through August 14, 2017. Two independent reviewers extracted data and we used random-effects analysis to calculate rate ratios (RR).

RESULTS

Three studies were included with a total of 82 PANDAS cases and 127 control children with obsessive-compulsive disorder or chronic tic disorder. PANDAS cases had a nonsignificantly increased RR of 2.33 [95% confidence interval [CI]: 0.63-8.70, P = 0.21, I = 28.3%] for exacerbations of neuropsychiatric symptoms in temporal proximity to a GABHS infection and no increased risk of GABHS infections (RR = 0.99, 95% CI: 0.56-1.73, P = 0.97, I = 45%) compared with the control children. However, PANDAS cases had an increased risk of neuropsychiatric exacerbations in general with a RR of 1.54 (95% CI: 1.12-2.11, P = 0.008, I = 0%) compared with the control children. The studies had methodologic heterogeneity, high risk of selection bias and differed concerning case definition and infection measures.

CONCLUSIONS

Our findings did not show significant evidence concerning higher rates of temporally associated GABHS infections and exacerbations of neuropsychiatric symptoms in children with PANDAS. The included studies were small and limited by low GABHS rates and exacerbations. Future studies with large population sizes and routine evaluations are needed to thoroughly examine the PANDAS hypothesis.

Antibasal Ganglia Antibodies and Antistreptolysin O in Noncomorbid ADHD

OBJECTIVE

An association between streptococcal infections, ABGA positivity, and no comorbidity ADHD (nc-ADHD) has been little investigated. The aim of this study was to evaluate the streptococcal infection frequency, defined entitled serum antistreptolysin O (ASO), and frequency of serum ABGA positivity in a sample of patients with nc-ADHD.

METHOD

In all 40 participants were investigated the ASO titer and ABGA.

RESULTS

The results showed that ABGA positivity was statistically significantly higher in patients affected by ADHD than in patients of a control group, and pathological values of ASO were statistically more frequent in the ADHD group than the control group.

CONCLUSION

These data suggest that streptococcal infections and autoimmune reactions against the basal ganglia are more frequent in ADHD patients than patients in a control group.

Gilles de la Tourette syndrome is not linked to contactin-associated protein receptor 2 antibodies

BACKGROUND

In Gilles de la Tourette syndrome (GTS) an immunopathogenic influence of autoantibodies is suspected. In familial GTS a disruption of the contactin-associated protein 2 gene (CNTNAP2), coding for the contactin-associated protein 2 (CASPR2), has been reported. Autoantibodies against CASPR2 are associated with other movement disorders like Morvan's syndrome. In addition, positive oligoclonal bands (OCB) in cerebrospinal fluid (CSF) have been found in more than a third of GTS patients, indicating a pathological intrathecal immunoglobulin synthesis. These findings drove the hypothesis that CASPR2 antibodies are involved in GTS.

METHODS

In this cross sectional study, 51 patients with GTS were examined for CASPR2 and other autoantibodies. We used indirect immunofluorescence or enzyme-linked visualization in cell-based assays on tissue sections from cerebellum (rat and monkey), hippocampus (rat), and immunoblots for the detection of specific or any other autoantibodies.

RESULTS

Serum samples from 51 GTS patients, mean age 35.0 ± 13.1 y, were analyzed. In none of the 51 GTS sera CASPR2 antibodies were detectable. Neither had we found any other specific autoantibodies (LGI1, NMDAR, AMPA1, AMPA/2 or GABAB1/B2). An anti-nuclear pattern of immunoreactivity was observed in 7/51 (14 %) samples. In these patients an immunoblot analysis was used to rule out antibodies directed against well-defined intracellular target antigens. A specific anti-neuronal binding pattern could not be seen in any of the tissue sections.

CONCLUSIONS

The results negate that CASPR2 antibodies play a role in the pathogenesis of Tourette syndrome and do not support the assumption that anti-neuronal antibodies are involved.

Streptococcal infection and immune response in children with Tourette's syndrome

BACKGROUND

Streptococcal infection and basal ganglia inflammation are hypothesized to be involved in Tourette's syndrome (TS). There is a need for effective therapies for managing TS. We studied streptococcal infection and immunity in TS following immunomodulator (pidotimod) therapy.

METHODS

Blood samples from 58 patients with TS and 128 age-matched healthy controls enabled measurement of antistreptolysin O (ASO), T cells, natural killer (NK) cells, interleukin-6 (IL-6) and interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α). Forty-four patients with abnormal T cell numbers were divided into two groups and treated with pidotimod granules (pidotimod group, n = 20) or pidotimod plus dopaminergic receptor antagonists (combination group, n = 24). Yale Global Tic Severity Scale (YGTSS) scores and immunologic indices were assessed after treatment.

RESULTS

An ASO >1:200 was found in 22.4% of children with TS, 7.5% of controls, and 38.9% of children with both TS and attention deficit hyperactivity disorder (ADHD) compared to 15.0% of children with TS alone (P < 0.05). Children with TS showed decreased CD3(+) and CD4(+) T cells, CD4(+)/CD8(+) ratio, IL-6 and IL-8, increased NKC and TNF-α (P < 0.05) as compared to controls. ASO-positive children with TS had lower CD4(+) T cells as compared to ASO-negative children with TS, and lower IL-6 and IL-8 levels as compared to controls (P < 0.05). After 8 weeks of pidotimod treatment, IL-8 was increased compared to either tiapride hydrochloride or haloperidol and pidotimod (P < 0.05).

CONCLUSIONS

Streptococcal infection in TS patients is associated with immune and cytokine dysfunction, which can be potentially managed with immunomodulator therapy.

Maternal history of autoimmune disease and later development of tourette syndrome in offspring

OBJECTIVE

In a nationwide prospective cohort study, we examined the possible association between maternal autoimmune disease (AD) and later diagnosis of Tourette syndrome (TS) in offspring.

METHOD

Data from national Danish health registers identified a cohort consisting of all children born in Denmark between 1990 and 2007 (n = 1,116,255), followed prospectively from birth until 2011, date of TS diagnosis, death, or emigration/disappearance, whichever came first. The incidence rate ratio (IRR) of TS, dependent on whether or not the mother had a prior diagnosis of AD, was estimated by Poisson regression with 95% CIs and adjusted for age, calendar time, place of birth, maternal and paternal age, parental psychiatric diagnoses other than TS, and parental TS.

RESULTS

The cohort contributed a total of 13,000,162 person years and 2,442 participants with a diagnosis of TS (414 females and 2,028 males). Prior maternal AD was found in 110 of the 2,442 children with TS, corresponding to an increased risk of TS, with an adjusted IRR of 1.22 (95% CI = 1.01-1.48). Maternal history of a prior AD increased the risk of TS in males, with an adjusted IRR of 1.29 (95% CI = 1.05-1.58), but not in females, with an adjusted IRR of 0.89 (95% CI = 0.52-1.52).

CONCLUSION

Maternal AD was associated with a 29% increased incidence rate of TS in male offspring. This finding supports the hypothesis that neuroimmunological disorders may act as a component in the etiology of a subset of TS.

A personal 35 year perspective on Gilles de la Tourette syndrome: assessment, investigations, and management

After having examined the definition, clinical phenomenology, comorbidity, psychopathology, and phenotypes in the first paper of this Series, here I discuss the assessment, including neuropsychology, and the effects of Gilles de la Tourette syndrome with studies showing that the quality of life of patients with Tourette's syndrome is reduced and that there is a substantial burden on the family. In this paper, I review my local and collaborative studies investigating causal factors (including genetic vulnerability, prenatal and perinatal difficulties, and neuro-immunological factors). I also present my studies on neuro-imaging, electro-encephalograms, and other special investigations, which are helpful in their own right or to exclude other conditions. Finally, I also review our studies on treatment including medications, transcranial magnetic stimulation, biofeedback, target-specific botulinum toxin injections, biofeedback and, in severe refractory adults, psychosurgery and deep brain stimulation. This Review summarises and highlights selected main findings from my clinic (initially The National Hospital for Neurology and Neurosurgery Queen Square and University College London, UK, and, subsequently, at St George's Hospital, London, UK), and several collaborations since 1980. As in Part 1 of this Series, I address the main controversies in the fields and the research of other groups, and I make suggestions for future research.

The role of immune mechanisms in Tourette syndrome

Tourette syndrome (TS) is a childhood-onset tic disorder associated with abnormal development of brain networks involved in the sensory and motor processing. An involvement of immune mechanisms in its pathophysiology has been proposed. Animal models based on active immunization with bacterial or viral mimics, direct injection of cytokines or patients' serum anti-neuronal antibodies, and transgenic approaches replicated stereotyped behaviors observed in human TS. A crucial role of microglia in the neural-immune crosstalk within TS and related disorders has been proposed by animal models and confirmed by recent post mortem studies. With analogy to autism, genetic and early life environmental factors could foster the involvement of immune mechanisms to the abnormal developmental trajectories postulated in TS, as well as lead to systemic immune dysregulation in this condition. Clinical studies demonstrate an association between TS and immune responses to pathogens like group A Streptococcus (GAS), although their role as risk-modifiers is still undefined. Overactivity of immune responses at a systemic level is suggested by clinical studies exploring cytokine and immunoglobulin levels, immune cell subpopulations, and gene expression profiling of peripheral lymphocytes. The involvement of autoantibodies, on the other hand, remains uncertain and warrants more work using live cell-based approaches. Overall, a body of evidence supports the hypothesis that disease mechanisms in TS, like other neurodevelopmental illnesses (e.g. autism), may involve dysfunctional neural-immune cross-talk, ultimately leading to altered maturation of brain pathways controlling different behavioral domains and, possibly, differences in organising immune and stress responses. This article is part of a Special Issue entitled SI: Neuroimmunology in Health And Disease.

Immune-mediated animal models of Tourette syndrome

An autoimmune diathesis has been proposed in Tourette syndrome (TS) and related neuropsychiatric disorders such as obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism and anorexia nervosa. Environmental triggers including infection and xenobiotics are hypothesized to lead to the production of brain-directed autoantibodies in a subset of genetically susceptible individuals. Although much work has focused on Group A Streptococcus (GAS), the role of this common childhood infection remains controversial. Animal model studies based on immune and autoantibody findings in TS have demonstrated immunoglobulin (Ig) deposits and stereotypic movements and related behavioral disturbances reminiscent of TS following exposure to GAS, other activators of host anti-microbial responses, soluble immune mediators and anti-GAS or anti-neuronal antibodies. Demonstration of the ability to recreate these abnormalities through passive transfer of serum IgG from GAS-immunized mice into naïve mice and abrogation of this activity through depletion of IgG has provided compelling evidence in support of the autoimmune hypothesis. Immunologically-based animal models of TS are a potent tool for dissecting the pathogenesis of this serious neuropsychiatric syndrome.

Immunization with DAT fragments is associated with long-term striatal impairment, hyperactivity and reduced cognitive flexibility in mice

Background

Possible interactions between nervous and immune systems in neuro-psychiatric disorders remain elusive. Levels of brain dopamine transporter (DAT) have been implicated in several impulse-control disorders, like attention deficit / hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Here, we assessed the interplay between DAT auto-immunity and behavioural / neurochemical phenotype.

Methods

Male CD-1 mice were immunized with DAT peptide fragments (DAT-i), or vehicle alone (VEH), to generate elevated circulating levels of DAT auto-antibodies (aAbs). Using an operant delay-of-reward task (20 min daily sessions; timeout 25 sec), mice had a choice between either an immediate small amount of food (SS), or a larger amount of food after a delay (LL), which increased progressively across sessions (from 0 to 150 sec).

Results

DAT-i mice exhibited spontaneous hyperactivity (2 h-longer wake-up peak; a wake-up attempt during rest). Two sub-populations differing in behavioural flexibility were identified in the VEH control group: they showed either a clear-cut decision to select LL or clear-cut shifting towards SS, as expected. Compared to VEH controls, choice-behaviour profile of DAT-i mice was markedly disturbed, together with long-lasting alterations of the striatal monoamines. Enhanced levels of DA metabolite HVA in DAT-i mice came along with slower acquisition of basal preferences and with impaired shifting; elevation also in DOPAC levels was associated with incapacity to change a rigid selection strategy. This scarce flexibility of performance is indicative of a poor adaptation to task contingencies.

Conclusions

Hyperactivity and reduced cognitive flexibility are patterns of behaviour consistent with enduring functional impairment of striatal regions. It is yet unclear how anti-DAT antibodies could enter or otherwise affect these brain areas, and which alterations in DAT activity exactly occurred after immunization. Present neuro-behavioural alterations, coming along with an experimentally-induced rise of circulating DAT-directed aAbs, open the issue of a potential role for auto-immunity in vulnerability to impulse-control disorders.

Movement disorders in autoimmune diseases

Movement disorders have been known to be associated with a variety of autoimmune diseases, including Sydenham's chorea, pediatric autoimmune neuropsychiatric disorders associated with streptococcus, systemic lupus erythematosus, antiphospholipid syndrome, gluten sensitivity, paraneoplastic and autoimmune encephalopathies. Tremors, dystonia, chorea, ballism, myoclonus, parkinsonism, and ataxia may be the initial and even the only presentation of these autoimmune diseases. Although antibodies directed against various cellular components of the central nervous system have been implicated, the pathogenic mechanisms of these autoimmune movement disorders have not yet been fully elucidated. Clinical recognition of these autoimmune movement disorders is critically important as many improve with immunotherapy or dietary modifications, particularly when diagnosed early. We discuss here the clinical features, pathogenic mechanisms, and treatments of movement disorders associated with autoimmune diseases, based on our own experience and on a systematic review of the literature.

Association between infection early in life and mental disorders among youth in the community: a cross-sectional study

BACKGROUND

The objective of this study was to examine the association between infection early in life and mental disorders among youth in the community.

METHODS

Data were drawn from the MECA (Methods in Epidemiology of Child and Adolescent psychopathology), a community-based study of 1,285 youth in the United States conducted in 1992. Multiple logistic regression analyses were used to investigate the association between parent/caregiver-reported infection early in life and DSM/DISC diagnoses of mental disorders at ages 9-17.

RESULTS

Infection early in life was associated with a significantly increased odds of major depression (OR = 3.9), social phobia (OR = 5.8), overanxious disorder (OR = 6.1), panic disorder (OR = 12.1), and oppositional defiant disorder (OR = 3.7).

CONCLUSIONS

These findings are consistent with and extend previous results by providing new evidence suggesting a link between infection early in life and increased risk of depression and anxiety disorders among youth. These results should be considered preliminary. Replication of these findings with longitudinal epidemiologic data is needed. Possible mechanisms are discussed.

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infection (PANDAS): a Controversial Diagnosis

Despite more than a decade of studying pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS), it is still not possible to confirm its existence and whether it is a poststreptococcal autoimmune disorder. Many controversies remain: the diagnostic criteria have not been validated, evidence of autoimmunity remains inconclusive, evidence of a genetic predisposition is weak, and streptococcal infections are common in childhood and could represent only a trigger of exacerbations of tics and obsessive-compulsive disorder. Patients who fit the PANDAS criteria appear to represent a subgroup of children with chronic tic disorder and/or obsessive-compulsive disorder who may experience symptom exacerbations after group A β-hemolytic streptococci infections; however, those infections are not the sole or even the most common antecedent of exacerbations. There is not enough evidence to support PANDAS as a unique clinical entity.

The PANDAS subgroup of tic disorders and childhood-onset obsessive-compulsive disorder

Diagnosis and treatment of the PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) variant of Gilles de la Tourette syndrome (GTS) and childhood-onset obsessive-compulsive disorder (OCD) are still controversial issues. Most cross-sectional studies confirm a significant association between GTS and the development of an immune response against group A beta-hemolytic streptococcus (GABHS). Moreover, longitudinal retrospective studies suggest that a recent exposure to GABHS might be a risk factor for the onset of tics and obsessive-compulsive symptoms. However, further evidence from longitudinal prospective research is needed to verify whether a temporal association between GABHS infections and symptom exacerbations is a useful and reliable criterion for the diagnosis of PANDAS. In addition, preliminary results suggest that the PANDAS spectrum might be enlarged to include attention deficit/hyperactivity disorder. Although a number of immunological biomarkers have been proposed as markers of the PANDAS variant, at present, none of these has been conclusively proved useful to diagnose and monitor disease course in children with a suspicion of PANDAS. Finally, despite their empirical use in community settings, we still lack conclusive, evidence-based data regarding the usefulness of antibiotic and immunomodulatory treatments in children with PANDAS. Given the relevance of this topic for general pediatric health, additional research efforts to solve all the pending issues and the hottest points of debate are warranted.

Immunopathogenic mechanisms in tourette syndrome: A critical review

Tourette syndrome (TS) has a multifactorial etiology, in which genetic, environmental, immunological and hormonal factors interact to establish vulnerability. This review: (i) summarizes research exploring the exposure of TS patients to immune-activating environmental factors, and (ii) focuses on recent findings supporting a role of the innate and adaptive immune systems in the pathogenesis of TS and related disorders. A higher exposure prior to disease onset to group A beta-haemolytic streptococcal (GABHS) infections in children with tics and obsessive-compulsive (OC) symptoms has been documented, although their influence upon the course of disease remains uncertain. Increased activation of immune responses in TS is suggested by changes in gene expression profiles of peripheral immune cells, relative frequency of lymphocyte subpopulations, and synthesis of immune effector molecules. Increased activity of cell-mediated mechanisms is suggested by the increased expression of genes controlling natural killer and cytotoxic T cells, increased plasma levels of some pro-inflammatory cytokines which correlate with disease severity, and increased synthesis of antineuronal antibodies. Important methodological differences might account for some inconsistency among results of studies addressing autoantibodies in TS. Finally, a general predisposition to autoimmune responses in TS patients is indicated by the reduced frequency of regulatory T cells, which induce tolerance towards self-antigens. Although the pathogenic role of immune activation in TS has not been definitively proven, a pathophysiological model is proposed to explain the possible effect of immunity upon dopamine transmission regulation and the generation of tics.

M-protein and other intrinsic virulence factors of Streptococcus pyogenes are encoded on an ancient pathogenicity island

BACKGROUND

The increasing number of completely sequenced bacterial genomes allows comparing their architecture and genetic makeup. Such new information highlights the crucial role of lateral genetic exchanges in bacterial evolution and speciation.

RESULTS

Here we analyzed the twelve sequenced genomes of Streptococcus pyogenes by a naïve approach that examines the preferential nucleotide usage along the chromosome, namely the usage of G versus C (GC-skew) and T versus A (TA-skew). The cumulative GC-skew plot presented an inverted V-shape composed of two symmetrical linear segments, where the minimum and maximum corresponded to the origin and terminus of DNA replication. In contrast, the cumulative TA-skew presented a V-shape, which segments were interrupted by several steep slopes regions (SSRs), indicative of a different nucleotide composition bias. Each S. pyogenes genome contained up to nine individual SSRs, encompassing all described strain-specific prophages. In addition, each genome contained a similar unique non-phage SSR, the core of which consisted of 31 highly homologous genes. This core includes the M-protein, other mga-related factors and other virulence genes, totaling ten intrinsic virulence genes. In addition to a high content in virulence-related genes and to a peculiar nucleotide bias, this SSR, which is 47 kb-long in a M1GAS strain, harbors direct repeats and a tRNA gene, suggesting a mobile element. Moreover, its complete absence in a M-protein negative group A Streptococcus natural isolate demonstrates that it could be spontaneously lost, but in vitro deletion experiments indicates that its excision occurred at very low rate. The stability of this SSR, combined to its presence in all sequenced S. pyogenes sequenced genome, suggests that it results from an ancient acquisition.

CONCLUSION

Thus, this non-phagic SSR is compatible with a pathogenicity island, acquired before S. pyogenes speciation. Its potential excision might bear relevance for vaccine development, because vaccines targeting M-protein might select for M-protein-negative variants that still carry other virulence determinants.

Tourette syndrome and obsessive-compulsive disorder

Tourette syndrome and obsessive-compulsive disorder are neuropsychiatric disorders that have sparked considerable interest over the decades. They are the focus of research for a remarkable diversity of disciplines, ranging from neuroimagers and prenatal epidemiologists to experts in the neural circuits that connect the cortex with the basal ganglia, as well as neuroimmunologists focusing on brain-based autoimmune phenomena. Several hypotheses have been put forward to explain the onset and exacerbation of these illnesses. Here, we discuss the clinical phenomenology and treatment options that are currently available. New psychopharmacological agents are being used that are based on a greater understanding of the neurobiology and are being used in combination with behavioral interventions. Longitudinal clinical investigations into clinical symptoms and the natural course are providing additional clues on the underlying pathophysiology. Recent advances in research models are also reviewed in an attempt to clarify some of the molecular etiologies that lead to these disorders.

PANDAS anorexia nervosa--endangered, extinct or nonexistent?

OBJECTIVE

Substantial evidence exists for the concept of pediatric autoimmune neuropsychiatric disorders associated with streptoccoccal infection (PANDAS) such as some cases of obsessive-compulsive disorder and tics/Tourette's syndrome. More recently PANDAS-AN has been described. The aim of this article is to provide a critical review of this concept.

METHOD

The literature was searched using Medline, Psychinfo, and Google.

RESULTS

There is some evidence for the entity of PANDAS-AN but this is considerably limited by a wide range of methodological problems, including the seemingly low prevalence, the lack of clarity in diagnostic criteria, and the lack of specificity in the diagnostic tests. Innovative treatment approaches hold promise but require further evaluation.

CONCLUSION

Further research into PANDAS-AN, using more clearly defined and consistent diagnostic criteria is needed, given the potential for enhancing the understanding of the pathogenesis of AN and for more effective treatments.

Chain reaction or time bomb: a neuropsychiatric-developmental/neurodevelopmental formulation of tourettisms, pervasive developmental disorder, and schizophreniform symptomatology associated with PANDAS

We present the case of a boy who over time sequentially exhibited symptoms consistent with a pervasive developmental disorder, schizophreniform symptomatology, multiple motor and vocal tics, and myoclonus. During this period he experienced multiple episodes of group A beta-haemolytic streptococcal (strep) infection confirmed by culture and serological studies. We speculate that paediatric autoimmune neuropsychiatric disorder associated with strep (PANDAS) may have served as an element in a complex chain of causation influencing the expression of his symptoms. Our main emphasis is to utilize our case study as an example of the application in case formulation of the neuropsychiatric developmental model and of the neurodevelopmental model on symptom ontogenesis and clinical outcome.

Tourette's syndrome: clinical features, pathophysiology, and therapeutic approaches

Tourette's syndrome (TS) is a disorder characterized by simple and complex motor tics, vocal tics, and frequently obsessive-compulsive symptoms, its onset occurs before the age of 21. Typically, TS shows a waxing and waning course, but a chronification of the tics, even during later life, is often observed, TS mainly occurs in boys, and shows genetic heritability with differing penetrance. The pathological mechanism is still unclear. Neuroanatomical and neuroimaging studies, as well as effective treatment using antipsychotics, suggest that a disturbance of the dopaminergic system in the basal ganglia plays an important role in the pathogenesis of TS, Several possibly causative mechanisms of the disturbed dopaminergic neurotransmission are discussed, with the main emphasis on the-infection-triggered- inflammatory immune process, Extrapyramidal movement disorders are known to occur as a symptom of poststreptococcal disease, such as in Sydenham's chorea. Cases of childhood TS are proposed to be caused by such a post-streptococcal mechanism, being part of a spectrum of childhood neurobehavioral disorders termed pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS), The overlap between TS and PANDAS is discussed, and a critical view of the PANDAS concept is presenter], The therapeutic implications of the different pathological mechanisms are described, taking into consideration not only the acute or chronic natures of different infections, but also an autoimmune process, Moreover, therapeutic strategies using typical and atypical antipsychotics, and also experimental therapies such as repetitive transcranial magnetic stimulation and deep brain stimulation, are critically discussed.

Tourette syndrome and tic disorders: a decade of progress

OBJECTIVE

This is a review of progress made in the understanding of Tourette syndrome (TS) during the past decade including models of pathogenesis, state-of-the-art assessment techniques, and treatment.

METHOD

Computerized literature searches were conducted under the key words "Tourette syndrome," "Tourette disorder," and "tics." Only references from 1996-2006 were included.

RESULTS

Studies have documented the natural history of TS and the finding that tics usually improve by the end of the second decade of life. It has also become clear that TS frequently co-occurs with attention-deficit/hyperactivity disorder), obsessive-compulsive disorder, and a range of other mood and anxiety disorders. These comorbid conditions are often the major source of impairment for the affected child. Advances have also been made in understanding the underlying neurobiology of TS using in vivo neuroimaging and neurophysiology techniques. Progress on the genetic front has been less rapid. Proper diagnosis and education (involving the affected child and his or her parents, teachers, and peers) are essential prerequisites to the successful management of children with TS. When necessary, modestly effective antitic medications are available, although intervening to treat the comorbid attention-deficit/hyperactivity disorder and/or obsessive-compulsive disorder is usually the place to start.

CONCLUSIONS

Prospective longitudinal studies and randomized clinical trials have led to the refinement of several models of pathogenesis and advanced our evidence base regarding treatment options. However, fully explanatory models are needed that would allow for more accurate prognosis and the development of targeted and efficacious treatments.

Tic disorders in childhood

Despite our familiarity with tic disorders, their management remains challenging. The difficulty seldom relates to the diagnosis, which is usually based on the history, but rather in dealing with the impact of the tics and multiple comorbidities. The child and family must be educated and must be taught how to facilitate a positive attitude among others who come in contact with the patient. Knowledge and acceptance of the tics by other family members, peers, teachers, and coaches often become central to the child's well-being. Although many children can be managed without pharmacotherapy, medications are often central to achieving success. The goals of therapy and the appropriate choice of medication must be individualized. We are frequently challenged not only by the wide array of medication choices available but also by the decision of which symptom to treat first. The tics, despite being flamboyant, are often viewed by the child and family as less disabling than co-occurring conditions, such as attention-deficit hyperactivity disorder, obsessive-compulsiveness, or rage. Even when tics are the major issue, patients must define their goals for therapy. It is unreasonable to expect a complete resolution of tics and safety usually rules in favor of better tolerated but potentially less efficacious therapies. Developing strategies to minimize the lifelong impact of the multiple components of Tourette syndrome is an essential aspect of the care of these patients.

Identification of pyruvate kinase as an antigen associated with Tourette syndrome

Immune responses to beta-hemolytic streptococcal infections are hypothesized to trigger tic disorders and early-onset obsessive-compulsive disorder (OCD) in some pediatric populations. Here we identify the M1 isoform of the glycolytic enzyme, pyruvate kinase (PK) as an autoimmune target in Tourette syndrome and associated disorders. Antibodies to PK reacted strongly with surface antigens of infectious strains of streptococcus, and antibodies to streptococcal M proteins reacted with PK. Moreover, immunoreactivity to PK in patients with exacerbated symptoms who had recently acquired a streptococcal infection was 7-fold higher compared to patients with exacerbated symptoms and no evidence of a streptococcal infection. These data suggest that PK can function as an autoimmune target and that this immunoreactivity may be associated with Tourette syndrome, OCD, and associated disorders.

Increased antistreptococcal antibody titers and anti-basal ganglia antibodies in patients with Tourette syndrome: controlled cross-sectional study

The association between Tourette syndrome, attention-deficit hyperactivity disorder (ADHD), and obsessive-compulsive disorder following streptococcal infections has been documented, but with conflicting reports. We thus felt it was important to investigate this association in a group of Italian patients not previously documented. We took blood on 69 patients with Tourette syndrome and 72 age- and sex-matched tic-free controls. Laboratory staff were blind to the diagnostic status of the subjects. Evidence of recent streptococcal infection was defined using antistreptolysin titers. Anti-basal ganglia antibodies were determined using human basal ganglia sections. Statistical analysis was conducted using analysis of variance and chi-square tests. Raised antistreptolysin titers were found in 41 of 69 (59%) patients with Tourette syndrome and 14 of 72 (19%) controls (P = .000). Positive anti-basal ganglia antibodies were found in 22 of 69 (32%) subjects with Tourette syndrome compared with 7 of 72 (10%) controls, which was also significant (P = .002). Raised antistreptolysin titers were detected in 18 of 22 (82%) patients with Tourette syndrome with positive anti-basal ganglia antibodies and 22 of 47 (47%) patients with negative anti-basal ganglia antibodies (P = .01). These results support the reported association between streptococcal infection and anti-basal ganglia antibodies and some patients with Tourette syndrome.

Autoimmune neuropsychiatric disorders associated with streptococcal infection: Sydenham chorea, PANDAS, and PANDAS variants

Streptococcal infection in children is usually benign and self-limited. In a small percentage of children, prominent neurologic and/or psychiatric sequelae can occur. Sydenham chorea is the best defined and best recognized. PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection) is a well-defined syndrome in which tics (motor and/or vocal) and/or obsessive-compulsive disorder consistently exacerbate in temporal correlation to a group A beta-hemolytic streptococcal infection. PANDAS constitutes a subset of children with tics, Tourette syndrome, and obsessive-compulsive disorder. In addition to strictly defined PANDAS, we and others have recognized several PANDAS variants, including adult-onset variant, a dystonic variant, a myoclonic variant, and a "chronic" PANDAS variant. The nosology and classification of these entities are rapidly evolving. The recognition that some pediatric neurobehavioral syndromes have infectious and/or immunologic triggers points to important new avenues of disease treatment. In this review, we summarize this complex and rapidly evolving area of clinical research.

Tic disorders: neural circuits, neurochemistry, and neuroimmunology

The neuroanatomy and neurochemistry underlying tic disorders are thought to involve corticostriatothalamocortical circuits and dysregulation of their component neurotransmitter systems. Tourette syndrome is a tic disorder that begins in childhood and follows a waxing and waning course of tic severity. Although it is generally believed to have a genetic component, its etiology has not been fully elucidated. The clinical entity pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) has led some to suggest that the pathophysiology of tics in some individuals might involve a postinfectious autoimmune component. We review the neural circuits and neurochemistry of Tourette syndrome and evaluate the evidence for and against a role for autoimmunity in the expression of tics.

Contemporary assessment and pharmacotherapy of Tourette syndrome

To develop a guide to clinical assessment and pharmacotherapy for children and adults with Tourette syndrome (TS), we reviewed published literature over the past 25 years to identify original articles and reviews on the assessment and pharmacological treatment of Tourette syndrome, attention-deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). The literature search also included a survey of reviews published in book chapters. The assessment section was compiled from several reviews. Pharmacological treatments were classified into those with strong empirical support (as evidenced by two positive placebo-controlled studies for tics, OCD, or ADHD in TS samples); modest empirical support (one positive placebo-controlled study), or minimal support (open-label data only). We conclude that accurate diagnosis, including identification of comorbid conditions, is an essential step toward appropriate treatment for patients with TS. In many patients with TS, symptom management requires pharmacotherapy for tics or coexisting conditions. The evidence supporting efficacy and safety for medications used in patients with TS varies. But this evidence offers the best guide to clinical practice.

Síndromes neuropsiquiátricas pós-estreptocócicas

Nesta revisão narrativa, o nosso objetivo foi descrever as síndromes neuropsiquiátricas pós-estreptocócicas e discuti-las à luz das evidências científicas atuais sobre os possíveis mecanismos patogenéticos envolvidos. Nos últimos anos, uma série de distúrbios do movimento, como tiques, distonia, parkinsonismo, e transtornos psiquiátricos, como o transtorno obsessivo-compulsivo (TOC) e o transtorno de hiperatividade com déficit de atenção (THDA), vem sendo considerada parte do espectro das manifestações pós-estreptocócicas. O termo PANDAS (acrônimo do inglês: pediatric autoimmune neuropsychiatric disorder associated with streptococcus) foi inclusive cunhado para descrever um subgrupo de pacientes com TOC e tiques que exibe flutuação clínica dos sintomas associada a infecção estreptocócica. Entretanto a análise crítica das evidências clinicolaboratoriais não apóia esse espectro ampliado das manifestações pós-estreptocócicas. Apenas na coréia de Sydenham há evidências consistentes de patogênese mediada por processo auto-imune pós-estreptocócico.

Antineural antibody in patients with Tourette's syndrome and their family members

It has been proposed that antineural antibodies were present in patients with Tourette's syndrome (TS) and other neuropsychiatric disorders. The purpose of our study was to investigate the presence of antineural antibodies in the individuals with Tourette's syndrome and the family members of TS patients. The sera of four TS patients with no current streptococcal infection, their tic-free family members including father, mother and sibling, and a age-matched control group who were tic free were assayed for antineural antibodies directed against rat tissue and neurons in primary cell culture. There were prominent antineural antibodies present in TS patients and their first-degree family members, but not in the control group. Western blotting showed proteins of about 120 kDa in their sera that were not present in the sera of controls. The preliminary results of our study suggest the importance of genetic vulnerability in the immunological pathophysiology of tic disorders. Future studies should investigate the interactions of genetics, environment, infectious agents, and immunity on symptom expression in families with tic disorders.

Gluten ataxia and post-streptococcal central nervous system syndromes: Emerging immune-mediated disorders of the central nervous system?

There is an "emerging concept" that central nervous system dysfunction can be caused by an aberrant immune response triggered by exogenous antigens such as the food allergen gluten or streptococcal infection. The hypothesis of a gluten sensitive ataxia remains unproven, but is worthy of consideration. The data in support of this hypothesis require critical review before any treatment recommendations can be formulated. The idea that anti-gliadin antibody seropositivity per se justifies the term "gluten sensitivity" is important because it offers potential therapeutic possibilities, including simple exclusion diets, for patients with anti-gliadin antibody-associated ataxia. Post-streptococcal basal ganglia dysfunction has various manifestations, all of which fall into a relatively well-defined symptom complex or syndrome. Anti-basal ganglia antibodies that are associated with serologic evidence of recent streptococcal infection are a potential diagnostic marker for this group of disorders, which includes Sydenham's chorea (SC) as the prototype. More recently subjects with pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection, Tourette's syndrome, obsessive-compulsive disorder and other movement disorders have been described in association with anti-basal ganglia antibodies. The apparent overlap between the clinical phenotype of SC, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections, Tourette's syndrome, and obsessive-compulsive disorder suggests that they may represent one disease entity. The current working hypothesis is that antibodies induced in response to streptococcal infection cross-react with antigenic determinants in the basal ganglia resulting in basal ganglia dysfunction. Although the experimental evidence is incomplete, there is sufficient evidence to support immune-mediated basal ganglia dysfunction as an emerging clinical entity. This has important implications for the diagnosis and treatment of subjects with these disorders. The latter includes the judicious use of antibiotic prophylaxis and immunomodulatory therapies. Apart from the diagnosis and management of SC, no consensus exists regarding the diagnosis and management of the other clinical entities within this group of disorders.

Annotation: PANDAS: a model for human autoimmune disease

BACKGROUND

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus infections (PANDAS) is a recently recognized syndrome in which pre-adolescent children have abrupt onsets of tics and/or obsessive-compulsive symptoms, a recurring and remitting course of illness temporally related to streptococcal infections, and associated neurologic findings including adventitious movements, hyperactivity and emotional lability.

METHODS

Inspired by observations of similar symptoms in children with Sydenham's chorea, a search was undertaken for clinical and laboratory evidence in support of the new syndrome.

RESULTS

Consistent and predictable clinical findings have been described in a large case series. Magnetic resonance imaging has supported the postulated pathobiology of the syndrome with evidence of inflammatory changes in basal ganglia. Antibasal ganglia antibodies have been found in some acute cases, mimicking streptococcal antigen epitopes.

CONCLUSIONS

While PANDAS remains a controversial diagnostic concept, it has stimulated new research endeavors into the possible links between bacterial pathogens, autoimmune reactions, and neuropsychiatric symptoms.

PANDAS: current status and directions for research

The recognition of the five criteria for PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) by Swedo et al established a homogenous subgroup of children with childhood onset obsessive-compulsive disorder (OCD) and/or tic disorders. The five clinical characteristics that define the PANDAS subgroup are the presence of OCD and/or tic disorder, prepubertal age of onset, abrupt onset and relapsing-remitting symptom course, association with neurological abnormalities during exacerbations (adventitious movements or motoric hyperactivity), and a temporal association between symptom exacerbations and a Group-A beta-hemolytic streptococcal (GAS) infection. These five criteria have been used for the purpose of systematic research on the phenomenology and unique therapies for the PANDAS subgroup as well as studies of the pathophysiology of post-streptococcal OCD and tic disorders. The etiology of OCD and tics in the PANDAS subgroup is unknown, but is theorized to occur as a result of post-streptococcal autoimmunity in a manner similar to that of Sydenham's chorea. The working hypothesis for the pathophysiology begins with a GAS infection in a susceptible host that incites the production of antibodies to GAS that crossreact with the cellular components of the basal ganglia, particularly in the caudate nucleus and putamen. The obsessions, compulsions, tics, and other neuropsychiatric symptoms seen in these children are postulated to arise from an interaction of these antibodies with neurons of the basal ganglia.

Restless legs syndrome: association with streptococcal or mycoplasma infection

Group A beta-hemolytic streptococcal infections have been reported to cause neuropsychiatric symptoms, such as chorea, tics, and obsessive-compulsive disorder, presumably through autoimmune damage to basal ganglia. Mycoplasma pneumoniae infections have also been reported to cause damage to the basal ganglia. Restless legs syndrome is a movement disorder with focal restlessness, an irresistible desire to move, and exacerbation by long periods of sitting or lying. We present three children with transient restless legs syndrome-like symptoms possibly associated with group A beta-hemolytic streptococcal infection or Mycoplasma pneumoniae infection. One of three patients had persistently elevated enzyme-linked immunosorbent optical density values against human caudate and putamen.

Antibasal ganglia antibodies and their relevance to movement disorders

PURPOSE OF REVIEW

Recently, autoaggressive immunological responses were included among the causative agents of basal ganglia dysfunction. Autoaggressive immune-mediated illnesses secondary to group A beta-haemolytic streptococcal infections present with motor and psychiatric symptoms, due to basal ganglia involvement. These disorders have been associated with serum antineuronal antibodies, relatively specific to human basal ganglia tissue. This review summarizes the most recent studies concerning antibasal ganglia antibodies, focusing on the associated phenotypes and the hypotheses concerning their pathogenicity.

RECENT FINDINGS

The spectrum of post-streptococcal neuropsychiatric disorders associated with antibasal ganglia antibodies seems broader than previously recognized. Other than chorea, tics and obsessive-compulsive disorder, which constituted the bulk of previously described disorders associated with antibasal ganglia antibodies, post-streptococcal neuropsychiatric disturbances include a wider range of motor and behavioural abnormalities, in keeping with the multifunctional role of the basal ganglia. An encephalitis lethargica-like illness following streptococcal infection was reported, and unusual adult-onset movement disorders associated with antibasal ganglia antibodies were documented. Moreover, investigators provided preliminary evidence for a pathogenic role of autoantibodies in Sydenham's chorea, the prototypic post-streptococcal neuropsychiatric disorder.

SUMMARY

Antibasal ganglia antibodies are relatively specific in identifying post-streptococcal neuropsychiatric disorders, which constitute a wider spectrum of movement disorders than previously recognized. Although their sensitivity in diagnosing Sydenham's chorea seems excellent, it is not yet possible to extrapolate this sensitivity to all the recently identified post-streptococcal neuropsychiatric disorders. The antigens targeted by these autoantibodies and their pathogenic importance are currently under investigation. Preliminary evidence suggests that antibasal ganglia antibodies may be pathogenic.

Dyskinesias and associated psychiatric disorders following streptococcal infections

BACKGROUND

The classical extrapyramidal movement disorder following beta haemolytic streptococcus (BHS) infection is Sydenham's chorea (SC). Recently, other post-streptococcal movement disorders have been described, including motor tics and dystonia. Associated emotional and behavioural alteration is characteristic.

AIMS

To describe experience of post-streptococcal dyskinesias and associated co-morbid psychiatric features presenting to a tertiary referral centre 1999-2002.

METHODS

In all patients, dyskinetic movement disorders followed BHS pharyngeal infection. BHS infection was defined by pharyngeal culture of the organism, or paired streptococcal serology. Movement disorders were classified according to international criteria, and validated by experienced child neurologists. Psychiatric complications were defined using ICD-10 criteria using a validated psychiatric interview.

RESULTS

In the 40 patients, the following dyskinetic movement disorders were present: chorea (n = 20), motor tics (n = 16), dystonia (n = 5), tremor (n = 3), stereotypies (n = 2), opsoclonus (n = 2), and myoclonus (n = 1). Sixty five per cent of the chorea patients were female, whereas 69% of the tic patients were male. ICD-10 psychiatric diagnoses were made in 62.5%. Using the same psychiatric instrument, only 8.9% of UK children would be expected to have an ICD-10 psychiatric diagnosis. Emotional disorders occurred in 47.5%, including obsessive-compulsive disorder (27.5%), generalised anxiety (25%), and depressive episode (17.5%). Additional psychiatric morbidity included conduct disorders (27.5%) and hyperkinetic disorders (15%). Psychiatric, movement, and post-streptococcal autoimmune disorders were commonly observed in family members. At a mean follow up of 2.7 years, 72.5% had continuing movement and psychiatric disorders.

CONCLUSION

Post-streptococcal dyskinesias occur with significant and disabling psychiatric co-morbidity and are potential autoimmune models of common "idiopathic" movement and psychiatric disorders in children. Multiple factors may be involved in disease expression including genetic predisposition, developmental status, and the patient's sex.

Prospective longitudinal study of children with tic disorders and/or obsessive-compulsive disorder: relationship of symptom exacerbations to newly acquired streptococcal infections

BACKGROUND

It has been proposed that infection by group A beta-hemolytic streptococci (GABHS) can trigger acute symptom exacerbations among patients with Tourette's syndrome (TS) or obsessive-compulsive disorder (OCD), via autoimmune mechanisms.

OBJECTIVE

To examine the temporal relationship between newly acquired GABHS infections (and other immunologic indices) and acute exacerbations of tics and obsessive-compulsive symptoms.

METHODS

Pediatric patients (7-17 years of age) with TS and/or OCD (N = 47) and healthy control subjects (N = 19) were prospectively monitored for newly acquired GABHS infections, nonspecific markers of acute inflammatory responses, and D8/17-reactive cells (a marker of rheumatic fever). Objective monthly ratings of tic and obsessive-compulsive symptom severity were used to determine the timing of symptom exacerbations.

RESULTS

The overall rate of acute exacerbations of neuropsychiatric symptoms was 0.56 exacerbations per patient per year. The average rate of new GABHS infections, using a stringent definition, was 0.42 infections per subject per year among patients, compared with 0.28 infections per subject per year for control subjects. The association between symptom exacerbations and new GABHS infections among patients was no greater than that expected on the basis of chance. At baseline, patients demonstrated significantly higher levels of D8/17-reactive cells and neopterin, compared with control subjects, but there was no consistent pattern of change when exacerbation time points were compared with baseline or follow-up time points.

CONCLUSIONS

The results suggest no clear relationship between new GABHS infections and symptom exacerbations in an unselected group of patients with TS and/or OCD.