Antineuronal antibodies in a group of children with obsessive-compulsive disorder and Tourette syndrome

Elevated antibody binding to striatal cholinergic interneurons in patients with pediatric acute-onset neuropsychiatric syndrome

Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) is characterized by the abrupt onset of significant obsessive-compulsive symptoms (OCS) and/or severe food restriction, together with other neuropsychiatric manifestations. An autoimmune pathogenesis triggered by infection has been proposed for at least a subset of PANS. The older diagnosis of Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcus (PANDAS) describes rapid onset of OCD and/or tics associated with infection with Group A Streptococcus. The pathophysiology of PANS and PANDAS remains incompletely understood. We recently found serum antibodies from children with rigorously defined PANDAS to selectively bind to cholinergic interneurons (CINs) in the striatum. Here we examine this binding in children with relapsing and remitting PANS, a more heterogeneous condition, collected in a distinct clinical context from those examined in our previous work, from children with a clinical history of Streptococcus infection. IgG from PANS cases showed elevated binding to striatal CINs in both mouse and human brain. Patient plasma collected during symptom flare decreased a molecular marker of CIN activity, phospho-riboprotein S6, in ex vivo brain slices; control plasma did not. Neither elevated antibody binding to CINs nor diminished CIN activity was seen with plasma collected from the same children during remission. These findings replicate what we have seen previously in PANDAS and support the hypothesis that at least a subset of PANS cases have a neuroimmune pathogenesis. Given the critical role of CINs in modulating basal ganglia function, these findings confirm striatal CINs as a locus of interest in the pathophysiology of both PANS and PANDAS.

Exploring the role of interleukin-1β and interleukin-6 in the pathophysiology of obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a highly prevalent neuropsychiatric disorder. Recently, there has been a growing interest in investigating the association between pro-inflammatory cytokines and the pathogenesis of OCD. However, studies targeting interleukin-1β (IL-1β) and interleukin-6 (IL-6) in OCD are limited. Therefore, the present study aimed to explore the potential role of pro-inflammatory cytokines IL-1β and IL-6 in the pathophysiology and development of OCD.

METHODS

This study recruited 58 OCD patients and 30 age-sex-matched healthy controls (HCs). A qualified psychiatrist diagnosed OCD patients and assessed HCs based on the Diagnostic and Statistical Manual for Mental Health Disorders, 5th edition (DSM-5) criteria. We measured the severity of OCD using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Serum IL-1β and IL-6 levels were measured using ELISA kits following the appropriate methods.

RESULTS

The results showed that serum IL-1β levels were significantly elevated in OCD patients compared to HCs (23.68±1.65 pg/ml vs. 15.75±1.02 pg/ml; p = 0.002). Similarly, OCD patients exhibited significantly higher serum IL-6 levels than HCs (44.97±0.73 pg/ml vs. 37.04±0.35 pg/ml; p<0.001). We observed both cytokines were positively correlated with the Y-BOCS scores in OCD patients (IL-1β: r = 0.380, p = 0.015; IL-6: r = 0.324, p = 0.026) which indicates their role in disease pathophysiology.

CONCLUSION

These results suggest that serum IL-1β and IL-6 levels may be associated with the pathophysiology of OCD. Also, these cytokines levels in blood samples can serve as early risk assessment tools for the development of OCD. We recommend further studies in a large and homogeneous population to support these findings.

Bilateral Globus Pallidus Externus Deep Brain Stimulation for the Treatment of Refractory Tourette Syndrome: An Open Clinical Trial

OBJECTIVES

We have previously proposed that Tourette syndrome (TS) is the clinical expression of the hyperactivity of globus pallidus externus (GPe) and various cortical areas. This study was designed to test this hypothesis by verifying the efficacy and safety of bilateral GPe deep brain stimulation (DBS) for treating refractory TS.

MATERIALS AND METHODS

In this open clinical trial, 13 patients were operated on. Target coordinates (center of GPe) were obtained by direct visualization. Physiological mapping was performed with macrostimulation and microrecording. Primary and secondary outcome measures were, respectively, responder and improvement rates of TS and comorbidities, according to pre- and postoperative scores on the following assessment instruments: Yale Global Tic Severity Scale, Yale-Brown Obsessive Compulsive Scale, Beck Depression Inventory/Hamilton Depression Rating Scale, Beck Anxiety Inventory/Hamilton Anxiety Rating Scale, and Concentrated Attention test.

RESULTS

Intraoperative stimulation (100 Hz/5.0V) did not produce any adverse effects or impact on tics. Microrecording revealed bursting cells discharging synchronously with tics in the central part of the dorsal half of GPe. Patients were followed up for a mean of 61.46±48.50 months. Responder rates were 76.9%, 75%, 71.4%, 71.4%, and 85.7%, respectively, for TS, obsessive-compulsive disorder (OCD), depression, anxiety, and attention deficit hyperactivity disorder. Mean improvements among responders in TS, OCD, depression, and anxiety were 77.4%, 74.7%, 89%, and 84.8%, respectively. After starting stimulation, tic improvement was usually delayed, taking up to ten days to manifest. Afterward, it increased over time, usually reaching its maximum at approximately one year postoperatively. The best stimulation parameters were 2.3V to 3.0V, 90 to 120 μsec, and 100 to 150 Hz, and the most effective contacts were the two dorsal ones. Two complications were registered: reversible impairment of previous depression and transient unilateral bradykinesia.

CONCLUSIONS

Bilateral GPe-DBS proved to be low risk and quite effective for treating TS and comorbidities, ratifying the pathophysiological hypothesis that led to this study. Moreover, it compared favorably with DBS of other targets currently in use.

Autoantibodies in patients with obsessive-compulsive disorder: a systematic review

Obsessive-compulsive disorder (OCD) is a frequent and debilitating mental illness. Although efficacious treatment options are available, treatment resistance rates are high. Emerging evidence suggests that biological components, especially autoimmune processes, may be associated with some cases of OCD and treatment resistance. Therefore, this systematic literature review summarizing all case reports/case series as well as uncontrolled and controlled cross-sectional studies investigating autoantibodies in patients with OCD and obsessive-compulsive symptoms (OCS) was performed. The following search strategy was used to search PubMed: "(OCD OR obsessive-compulsive OR obsessive OR compulsive) AND (antib* OR autoantib* OR auto-antib* OR immunoglob* OR IgG OR IgM OR IgA)". Nine case reports with autoantibody-associated OCD/OCS were identified: five patients with anti-neuronal autoantibodies (against N-methyl-D-aspartate-receptor [NMDA-R], collapsin response mediator protein [CV2], paraneoplastic antigen Ma2 [Ma2], voltage gated potassium channel complex [VGKC], and "anti-brain" structures) and four with autoantibodies associated with systemic autoimmune diseases (two with Sjögren syndrome, one with neuropsychiatric lupus, and one with anti-phospholipid autoantibodies). Six patients (67%) benefited from immunotherapy. In addition, eleven cross-sectional studies (six with healthy controls, three with neurological/psychiatric patient controls, and two uncontrolled) were identified with inconsistent results, but in six studies an association between autoantibodies and OCD was suggested. In summary, the available case reports suggest an association between OCD and autoantibodies in rare cases, which has been supported by initial cross-sectional studies. However, scientific data is still very limited. Thus, further studies on autoantibodies investigated in patients with OCD compared with healthy controls are needed.

Molecular Landscape of Tourette's Disorder

Tourette's disorder (TD) is a highly heritable childhood-onset neurodevelopmental disorder and is caused by a complex interplay of multiple genetic and environmental factors. Yet, the molecular mechanisms underlying the disorder remain largely elusive. In this study, we used the available omics data to compile a list of TD candidate genes, and we subsequently conducted tissue/cell type specificity and functional enrichment analyses of this list. Using genomic data, we also investigated genetic sharing between TD and blood and cerebrospinal fluid (CSF) metabolite levels. Lastly, we built a molecular landscape of TD through integrating the results from these analyses with an extensive literature search to identify the interactions between the TD candidate genes/proteins and metabolites. We found evidence for an enriched expression of the TD candidate genes in four brain regions and the pituitary. The functional enrichment analyses implicated two pathways ('cAMP-mediated signaling' and 'Endocannabinoid Neuronal Synapse Pathway') and multiple biological functions related to brain development and synaptic transmission in TD etiology. Furthermore, we found genetic sharing between TD and the blood and CSF levels of 39 metabolites. The landscape of TD not only provides insights into the (altered) molecular processes that underlie the disease but, through the identification of potential drug targets (such as FLT3, NAALAD2, CX3CL1-CX3CR1, OPRM1, and HRH2), it also yields clues for developing novel TD treatments.

Obsessive-Compulsive Disorder, PANDAS, and Tourette Syndrome: Immuno-inflammatory Disorders

In the last years, much focus has been given to the possible role of inflammatory and immunologic alterations in the pathophysiology of obsessive-compulsive disorder (OCD) and some related conditions, such as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) and Tourette syndrome (TS). Although the matter is intriguing, the available data are still controversial and/or limited. Therefore, the aim of this chapter was at reviewing and commenting on the literature on possible dysfunctions of inflammatory and immune system processes in OCD, PANDAS, and TS.This narrative review was carried out through searching PubMed and Google Scholar for English language papers from January 1985 to December 31, 2021.The data gathered up to now would suggest that the mechanisms involved might be heterogeneous according to the age of the patients and the disorder examined. Indeed, PANDAS seem more related to infections triggering autoimmunity not necessarily following group A beta-hemolytic streptococcal (GABHS) infection, as supposed in the past. Autoimmunity seems also important in TS, if coupled with an individual vulnerability that can be genetic and/or environmental. The data in adult OCD, albeit scattered and sometimes obtained in small samples of patients, would indicate that immune system and inflammatory processes are involved in the pathophysiology of the disorder. However, it is still unclear to conclude whether they are primary or secondary phenomena.In conclusion, taken together, the current findings pave that way towards novel and promising domains to explore the pathophysiology of OCD and related disorders, as well towards the development of innovative therapeutic strategy beyond current pharmacological paradigms.

Evaluation of antineuronal antibodies and 8-OHdG in mothers of children with autism spectrum disorder: a case-control study

OBJECTIVE

The purpose of our study was to investigated the anti-Yo, anti-Hu, anti-Ri, anti-amphiphysin antibody levels and 8-OHdG in mothers of children with autism.

METHODS

This study included 60 participants, 33 of whom were healthy mothers of 3-12-year-old children diagnosed with autism spectrum disorder (ASD) and the 27 others who constituted the control group, were healthy mothers with age-matched healthy children. Two groups were examined for plasma anti-Yo, anti-Hu, anti-amphiphysin and anti-Ri antibodies and, 8-OHdG levels. The participants were asked to accomplish a sociodemographic data form. The severity of ASD symptoms was evaluated according to the Childhood Autism Rating Scale (CARS).

RESULTS

Anti-amphiphysin antibody levels and anti-Ri antibody positivity were significantly higher in the case group (p = 0.001; p = 0.027, respectively). The two groups did not significantly differ in terms of anti-Yo and anti-Hu antibody levels and in terms of 8-OHdG levels (p = 0.065; p = 0.099; p = 0.490, respectively). The two groups did not significantly differ in terms of sociodemographic data (p > 0.05).

CONCLUSIONS

According to the our study, maternal antineuronal antibodies, such as anti-amphiphysin and anti-Ri, may contribute to the risk of childhood autism. Studies with larger samples are needed.KEY POINTSMaternal factors associated with autism should be investigated in order to create early diagnosis and treatment opportunities for autism.Based on the importance of immunological and cerebellar pathologies in autism aetiology, we aimed to investigate antineuronal antibodies in mothers of children with autism.Maternal antineuronal antibodies, such as anti-amphiphysin and anti-Ri, may contribute to the risk of childhood autism.High anti-amphiphysin antibody levels in mothers of children with autism may also occur against the amphiphysin in the structure of the SrGAP3 gene, which is associated with autism.

Gut Microbiome Composition Abnormalities Determined Using High-Throughput Sequencing in Children With Tic Disorder

OBJECT

To investigate the distribution characteristics of gut microbiota in children with tic disorder (TD) and the possible role of these characteristics in the pathogenesis of TD.

METHODS

The medical records of 28 children with TD treated at Wuxi Children's Hospital from January 1 to October 31, 2020, and 21 age-matched healthy children (controls) were included. The relative quantification of bacterial taxa was performed using 16S ribosomal RNA gene amplicon sequencing.

RESULTS

There was no significant difference in the alpha diversity of gut microbiota between the TD and control groups. Analyses of beta diversity were able to differentiate the TD patients from the healthy controls based on their gut microbiota. At the phylum level, the two groups were mainly composed of four phyla, Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. There were significant differences in Firmicutes and Actinobacteria between the two groups (P <0.05). At the level of genera, the abundance of Bifidobacterium and Collinsella reduced while that of Ruminococcaceae unclassified, Prevotella, Faecalibacterium, Coprobacillus, and Odoribacter increased in the TD group compared to that in the control group. The intergroup differences were significant (P < 0.05).

CONCLUSION

The abnormal composition of gut microbiota in children with TD suggests that the change in gut microbiota may play an important role in TD development.

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.

Effects of Celecoxib Adjunct to Selective Serotonin Reuptake Inhibitors on Obsessive-Compulsive Disorder

Introduction:

Inflammatory processes in the brain play an important role in the etiopathogenesis of Obsessive-Compulsive Disorder (OCD). Cyclooxygenase inhibitors, such as celecoxib reduce the production of proinflammatory cytokines. This double-blind study aimed to investigate the effects of adding celecoxib to Selective Serotonin Reuptake Inhibitors (SSRIs)on treating OCD.

Methods:

Sixty patients who met the diagnosis criteria for OCD based on the Diagnostic and Statistical Manual of Mental Disorders -Fourth Edition- Text Revision (DSM-IV-TR) were recruited in the present study. Two psychiatrists independently confirmed the diagnosis by performing structured interviews. The study participants included 23 patients who received SSRIs and celecoxib (400 mg twice daily) and 22 patients in the control group that received SSRIs and placebo. Moreover, at baseline, in weeks 4, 8, and 12, the explored patients were assessed by a psychiatrist using the Yale-Brown Obsessive-Compulsive Scale (Y-BCOS).

Results:

A significant difference was observed in the change of scores on the Y-BOCS in week 12, compared with the onset of the study between the study groups (t= −8.976, df=38, P=0.001). There was a significant difference between the study groups in obsession (F= 49.19, df= 1, P≤0.001), compulsion (F= 13.78, df= 1, P= 0.001), and OCD (F= 57.25, df= 1, P≤0.001), i.e., higher in the celecoxib group.

Conclusion:

This study showed that adjuvant treatment with celecoxib can further improve the symptoms of OCD in individuals receiving SSRIs.

Autoantibody-associated psychiatric syndromes in children: link to adult psychiatry

Studies show that psychiatric symptoms in adults and children are sometimes associated with serum neural autoantibodies. The significance of serum neural autoantibodies associated with psychiatric symptoms in children remains often unclear, but might be relevant for the extent and occurrence of psychiatric disease manifestation in later life, as well as therapy and outcome. For this narrative review, we sought articles listed in PubMed and published between 1988 and 2020 addressing the maternal-fetal transfer of neural autoantibodies and psychiatric disorders associated with serum neural autoantibodies. We identified six major subgroups of psychiatric disorders in children that are associated with serum neural autoantibodies: patients with attentional deficit hyperactivity disorder, autism spectrum disorder, obsessive compulsive disorder, Gilles de la Tourette syndrome, psychosis and catatonia. Furthermore, we summarized study findings from maternal-fetal transfer of Contactin-associated protein-like 2, N-methyl-D-aspartate receptor and fetal brain autoantibodies associated with behavioral effects in animals and humans. We hypothesize that the maternal transfer of serum neuronal autoantibodies during or after birth could result (1) in the ignition of an autoimmune-mediated inflammation having neurodevelopmental consequences for their children (autoimmune-priming-attack hypothesis) and (2) has a potential impact on the later manifestation of psychiatric disorders. Through this narrative review, we propose a diagnostic pathway for the clinical diagnosis of a potentially autoimmune origin of psychiatric symptoms in children while considering recent guidelines.

Searching for host immune-microbiome mechanisms in obsessive-compulsive disorder: A narrative literature review and future directions

Obsessive-compulsive disorder (OCD) is disabling and often treatment-refractory. Host immunity and gut microbiota have bidirectional communication with each other and with the brain. Perturbations to this axis have been implicated in neuropsychiatric disorders, but immune-microbiome signaling in OCD is relatively underexplored. We review support for further pursuing such investigations in OCD, including: 1) gut microbiota has been associated with OCD, but causal pathogenic mechanisms remain unclear; 2) early environmental risk factors for OCD overlap with critical periods of immune-microbiome development; 3) OCD is associated with increased risk of immune-mediated disorders and changes in immune parameters, which are separately associated with the microbiome; and 4) gut microbiome manipulations in animal models are associated with changes in immunity and some obsessive-compulsive symptoms. Theoretical pathogenic mechanisms could include microbiota programming of cytokine production, promotion of expansion and trafficking of peripheral immune cells to the CNS, and regulation of microglial function. Immune-microbiome signaling in OCD requires further exploration, and may offer novel insights into pathogenic mechanisms and potential treatment targets for this disabling disorder.

Diagnostic Approach to Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections (PANDAS): A Narrative Review of Literature Data

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) are clinical conditions characterized by the sudden onset of obsessive-compulsive disorder and/or tics, often accompanied by other behavioral symptoms in a group of children with streptococcal infection. PANDAS-related disorders, including pediatric acute-onset neuropsychiatric syndrome (PANS), childhood acute neuropsychiatric symptoms (CANS), and pediatric infection triggered autoimmune neuropsychiatric disorders (PITANDs), have also been described. Since first defined in 1998, PANDAS has been considered a controversial diagnosis. A comprehensive review of the literature was performed on PubMed and Scopus databases, searching for diagnostic criteria and diagnostic procedures of PANDAS and related disorders. We propose a test panel to support clinicians in the workout of PANDAS/PANS patients establishing an appropriate treatment. However, further studies are needed to improve our knowledge on these acute-onset neuropsychiatric conditions.

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.

What Does Immunology Have to Do With Normal Brain Development and the Pathophysiology Underlying Tourette Syndrome and Related Neuropsychiatric Disorders?

Objective: The goal of this article is to review the past decade's literature and provide a critical commentary on the involvement of immunological mechanisms in normal brain development, as well as its role in the pathophysiology of Tourette syndrome, other Chronic tic disorders (CTD), and related neuropsychiatric disorders including Obsessive-compulsive disorder (OCD) and Attention deficit hyperactivity disorder (ADHD). Methods: We conducted a literature search using the Medline/PubMed and EMBASE electronic databases to locate relevant articles and abstracts published between 2009 and 2020, using a comprehensive list of search terms related to immune mechanisms and the diseases of interest, including both clinical and animal model studies. Results: The cellular and molecular processes that constitute our "immune system" are crucial to normal brain development and the formation and maintenance of neural circuits. It is also increasingly evident that innate and adaptive systemic immune pathways, as well as neuroinflammatory mechanisms, play an important role in the pathobiology of at least a subset of individuals with Tourette syndrome and related neuropsychiatric disorders In the conceptual framework of the holobiont theory, emerging evidence points also to the importance of the "microbiota-gut-brain axis" in the pathobiology of these neurodevelopmental disorders. Conclusions: Neural development is an enormously complex and dynamic process. Immunological pathways are implicated in several early neurodevelopmental processes including the formation and refinement of neural circuits. Hyper-reactivity of systemic immune pathways and neuroinflammation may contribute to the natural fluctuations of the core behavioral features of CTD, OCD, and ADHD. There is still limited knowledge of the efficacy of direct and indirect (i.e., through environmental modifications) immune-modulatory interventions in the treatment of these disorders. Future research also needs to focus on the key molecular pathways through which dysbiosis of different tissue microbiota influence neuroimmune interactions in these disorders, and how microbiota modification could modify their natural history. It is also possible that valid biomarkers will emerge that will guide a more personalized approach to the treatment of these disorders.

Altered frequencies of Th17 and Treg cells in children and adolescents with obsessive-compulsive disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder with an etiopathophysiology that seems to include immune alterations. Previous studies have suggested that variations in the levels of circulating T cell subpopulations may be involved in psychiatric diseases. However, the role of these cells in OCD remains unexplored. Hence, the present study aimed to examine the levels of T helper 1 (Th1), Th2, Th17 and regulatory T (Treg) cells in patients with early-onset OCD and healthy controls.

METHODS

The assessment was performed in 99 children and adolescents with OCD and 46 control subjects. The percentages of circulating Th1, Th2, Th17 and Treg cells were evaluated using flow cytometry.

RESULTS

OCD patients had significantly higher levels of Th17 cells and lower percentages of Treg cells than healthy controls (p = 0.001 and p = 0.005, respectively). Furthermore, levels of Th17 cells progressively increased with the duration (p = 0.005) and severity of OCD (p = 0.008), whereas the percentages of Treg cells significantly declined with the duration of the disorder (p = 1.8 × 10^-5).

CONCLUSIONS

These results provide more evidence of the involvement of immune dysregulation, specifically an imbalance in the levels of circulating T helper and regulatory T cells, in the pathophysiology of early-onset OCD.

Immune-Related Comorbidities in Childhood-Onset Obsessive Compulsive Disorder: Lifetime Prevalence in the Obsessive Compulsive Disorder Collaborative Genetics Association Study

Objective: To evaluate the lifetime prevalence of infectious, inflammatory, and autoimmune disorders in a multisite study of probands with childhood-onset obsessive compulsive disorder (OCD) and their first-degree relatives. Methods: Medical questionnaires were completed by 1401 probands and 1045 first-degree relatives in the OCD Collaborative Genetics Association Study. Lifetime prevalence of immune-related diseases was compared with the highest available population estimate and reported as a point estimate with 95% adjusted Wald interval. Worst-episode OCD severity and symptom dimensions were assessed with the Yale-Brown Obsessive Compulsive Scale (YBOCS) and Symptom Checklist (YBOCS-CL). Results: Probands reported higher-than-expected prevalence of scarlet fever (4.0 [3.1-5.2]% vs. 1.0%-2.0%, z = 1.491, p < 0.001, n = 1389), encephalitis or meningitis (1.4 [0.9-2.1]% vs. 0.1%-0.4%, z = 5.913, p < 0.001, n = 1393), rheumatoid arthritis (1.1 [0.6-2.0]% vs. 0.2%-0.4%, z = 3.416, p < 0.001, n = 949) and rheumatic fever (0.6 [0.3-1.2]% vs. 0.1%-0.2%, z = 3.338, p < 0.001, n = 1390), but not systemic lupus erythematosus, diabetes, asthma, multiple sclerosis, psoriasis, or inflammatory bowel disease. First-degree relatives reported similarly elevated rates of scarlet fever, rheumatic fever, and encephalitis or meningitis independent of OCD status. There was no association between worst-episode severity and immune-related comorbidities, although probands reporting frequent ear or throat infections had increased severity of cleaning-/contamination-related symptoms (mean factor score 2.5 ± 0.9 vs. 2.3 ± 1.0, t = 3.183, p = 0.002, n = 822). Conclusion: These data suggest high rates of streptococcal-related and other immune-mediated diseases in patients with childhood-onset OCD and are consistent with epidemiological studies in adults noting familial clustering. Limitations include potential reporting bias and absence of a control group, underscoring the need for further prospective studies characterizing medical and psychiatric disease clusters and their interactions in children. Such studies may ultimately improve our understanding of OCD pathogenesis and aid in the development of adjunctive immune-modulating therapeutic strategies.

Obsessive-Compulsive Disorder: Autoimmunity and Neuroinflammation

PURPOSE OF REVIEW

Here, we propose to review the immuno-inflammatory hypothesis in OCD given the concurrent incidence of autoimmune comorbidities, infectious stigma, and raised levels of inflammatory markers in a significant subset of patients. A better understanding of the immune dysfunction in OCD may allow stratifying the patients in order to design personalized pharmaco/psychotherapeutic strategies.

RECENT FINDINGS

A persistent low-grade inflammation involving both innate and adaptive immune system with coexisting autoimmune morbidities and stigma of infectious events has been prominently observed in OCD. Hence, specific treatments targeting inflammation/infection are a feasible alternative in OCD. This review highlights that OCD is associated with low-grade inflammation, neural antibodies, and neuro-inflammatory and auto-immune disorders. In some subset of OCD patients, autoimmunity is likely triggered by specific bacterial, viral, or parasitic agents with overlapping surface epitopes in CNS. Hence, subset-profiling in OCD is warranted to benefit from distinct immune-targeted treatment modalities.

The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescent obsessive-compulsive disorder: Does comorbid anxiety disorder affect inflammatory response?

Recent adult etiologic studies indicated evidence linking increased inflammatory parameters with psychiatric disorders. The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio are easily obtainable clinical markers of inflammation and have been found to be increased in various medical and mental disorders. In this study, we aimed to investigate the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescents with obsessive-compulsive disorder (OCD). Secondarily, the effect of comorbid anxiety disorder with OCD on the inflammatory response was investigated. Sixty drug-naïve adolescents with OCD aged 12 to 18 years were enrolled in the patient group. Twenty-three of the OCD group had comorbid anxiety disorder (AD) and 37 had no comorbidities. One hundred twenty-eight adolescents in the same age range with no psychiatric disorders were recruited as the healthy control group. The severity of OCD symptoms was evaluated using the Children's Yale-Brown Obsessive Compulsive Scale. There were statistically significant differences in the neutrophil-lymphocyte ratio, white blood cell, neutrophil, and platelet counts among the three groups, even after adjusting for age and sex. The adolescents with OCD and AD had the highest neutrophil-lymphocyte ratio and white blood cell counts. A comorbid anxiety disorder diagnosis in addition to obsessive-compulsive disorder may increase the inflammatory response.

Challenges in the diagnosis and treatment of pediatric obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) affects 1%-3% of children worldwide and has a profound impact on quality of life for patients and families. Although our understanding of the underlying etiology remains limited, data from neuroimaging and genetic studies as well as the efficacy of serotonergic medications suggest the disorder is associated with the fundamental alterations in the function of cortico-striato-thalamocortical circuits. Significant delays to diagnosis are common, ultimately leading to more severe functional impairment with long-term developmental consequences. The clinical assessment requires a detailed history of specific OCD symptoms as well as psychiatric and medical comorbidities. Standardized assessment tools may aid in evaluating and tracking symptom severity and both individual and family functioning. In the majority of children, an interdisciplinary approach that combines cognitive behavioral therapy with a serotonin reuptake inhibitor leads to meaningful symptom improvement, although some patients experience a chronic, episodic course. There are limited data to guide the management of treatment-refractory illness in children, although atypical antipsychotics and glutamate-modulating agents may be used cautiously as augmenting agents. This review outlines a clinical approach to the diagnosis and management of OCD, highlighting associated challenges, and limitations to our current knowledge.

Individualized Immunological Data for Precise Classification of OCD Patients

Obsessive⁻compulsive disorder (OCD) affects about 2% of the general population, for which several etiological factors were identified. Important among these is immunological dysfunction. This review aims to show how immunology can inform specific etiological factors, and how distinguishing between these etiologies is important from a personalized treatment perspective. We found discrepancies concerning cytokines, raising the hypothesis of specific immunological etiological factors. Antibody studies support the existence of a potential autoimmune etiological factor. Infections may also provoke OCD symptoms, and therefore, could be considered as specific etiological factors with specific immunological impairments. Finally, we underline the importance of distinguishing between different etiological factors since some specific treatments already exist in the context of immunological factors for the improvement of classic treatments.

An Atypical Presentation of Pediatric Acute Neuropsychiatric Syndrome Responding to Plasmapheresis Treatment

Here we report a case of a 15-year-old female who had originally been diagnosed and treated unsuccessfully for schizophrenia, psychosis, severe anxiety, and depression. More in-depth history revealed an abrupt onset of her symptoms with remote acute infections and many exhibited characteristics of obsessive compulsive disorder with rituals. Work-up for underlying infectious, immunodeficiency, and autoimmune causes was unrevealing except for very high levels of anti-neuronal antibodies which have been linked to Pediatric Acute-onset Neuropsychiatric Syndrome (PANS). Treatment options were discussed with the family and it was decided to use a course of plasmapheresis based on previous studies demonstrating efficacy and its safety profile. After course of therapy, there was a dramatic resolution of her psychosis, OCD traits, and anxiety. She was able to stop all of her antipsychotic and anxiety medications and resume many of her previous normal daily activities. The effect of this treatment has been sustained to the present time. This case emphasizes the importance of exploring nontraditional treatments for severe, treatment-resistant mental illness which requires a multidisciplinary approach. Further research is warranted in larger populations to investigate pathomechanisms and treatment of PANs/PANDAs.

Anti-Basal Ganglia Antibodies and Streptococcal Infection in ADHD

OBJECTIVE

Group A Streptococcus has been associated with ADHD, tic disorders (TD), and obsessive-compulsive disorder (OCD) through anti-basal ganglia antibodies (ABGA).

METHOD

We investigated the association between ABGA and streptococcal exposure with behavioral, motor, and cognitive measures in 38 children with ADHD not comorbid to OCD or TD (nc-ADHD) and in 38 healthy children. An additional group of 15 children with TD and/or OCD was examined.

RESULTS

ABGA titers were present in 3% of nc-ADHD patients and controls but in 27% of TD and/or OCD patients. Evidence of streptococcal exposure was similar between ADHD patients and controls living in the same urban area. Behavioral, motor, and cognitive measures were not associated with anti-streptococcal antibodies.

CONCLUSION

ABGA do not distinguish nc-ADHD from controls. The differences in the frequency of streptococcal exposure in previous studies are determined by the dynamic nature of the infection rather than the behavioral phenotype of ADHD.

Cross-Sectional Evaluation of Plasma Vitamin D Levels in a Large Cohort of Italian Patients with Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections

BACKGROUND

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) are immune-mediated diseases characterized by obsessive-compulsive symptoms and/or tics triggered by group A Streptococcus infections. Despite the well-known action of 25-hydroxyvitamin D [25(OH)D] on different conditions driven by systemic inflammation, there are no data about the 25(OH)D status in patients with PANDAS.

AIMS

To evaluate plasma 25(OH)D levels in a large cohort of children and adolescents with PANDAS and comparing the results with healthy controls.

METHODS

We have evaluated plasma 25(OH)D levels in 179 Italian patients with PANDAS (49 females, 130 males, mean age at diagnosis: 101.4 ± 30.1 months) and in an age-, gender-, and body mass index-matched control group of 224 healthy subjects.

RESULTS

Patients with PANDAS have shown more frequently reduced 25(OH)D levels (<30 ng/mL) in comparison with controls (94.6% vs. 82.5%, p = 0.0007). Patients with PANDAS had also lower levels of 25(OH)D than controls (20.4 ± 6.9 ng/mL vs. 24.8 ± 7.3 ng/mL, p < 0.0001). This difference was observed during both winter (13.7 ± 3.25 ng/mL vs. 21.4 ± 5.9 ng/mL, p < 0.0001) and summer (21.8 ± 6.5 ng/mL vs. 32.5 ± 8.7 ng/mL, p < 0.0001). Notably, serum 25(OH)D levels correlated with both number of streptococcal (strep) infections before diagnosis of PANDAS (p < 0.005) and with infection recurrence (p < 0.005).

CONCLUSIONS

PANDAS patients have reduced 25(OH)D levels, which appear related to streptococcal infections and the probability of recurrence. Further long-term studies with higher number of patients are needed to investigate and confirm this relationship.

[Pediatric acute-onset neuropsychiatric syndrome: clinical/laboratory characteristics]

AIM

Based on the current conceptions on the genesis of hyperkinetic syndromes in children and adolescents, to single out a group of patients with suggestive PANS, compare clinical and laboratory results and determine clinical/laboratory characteristics of this syndrome.

MATERIAL AND METHODS

Sixty-nine patients with tics were studied using neurological examination, questionnaires and international scales for assessment of tics, obsessive-compulsive disorders and attention deficit hyperactivity disorder (ADHD). Laboratory tests included general blood tests, antistreptolysin O test, determination of rheumatoid factor, C-reactive protein, circulating immune complexes, nasopharyngeal wash for β-hemolytic streptococcus, antineuronal antibodies and immunoglobulins A, M, G, E, CD4, CD8-lymphocytes. The same tests were performed in the control group.

RESULTS AND CONCLUSION

Clinical symptoms were different by the severity and phenomenology of tic hyperkineses in patients with PANS compared to the patients with tics without immune disorders. Most of the patients were diagnosed with Tourette syndrome. ADHD was the most common diagnosis in the PANS group. Its frequency was 2.5 higher in the male patients. A chronic focus of infection did no predict the development of PANS. Based on the laboratory results, one can assume that β-hemolytic streptococcus A infection, lower JgM levels and an elevated CD8+ lymphocytes predict the development of autoimmune mental and neurological disorders in the group of PANS patients.

Inflammatory dysregulation of monocytes in pediatric patients with obsessive-compulsive disorder

BACKGROUND

Although the exact etiology of obsessive-compulsive disorder (OCD) is unknown, there is growing evidence of a role for immune dysregulation in the pathophysiology of the disease, especially in the innate immune system including the microglia. To test this hypothesis, we studied inflammatory markers in monocytes from pediatric patients with OCD and from healthy controls.

METHODS

We determined the percentages of total monocytes, CD16+ monocytes, and classical (CD14^highCD16-), intermediate (CD14^highCD16^low), and non-classical (CD14^lowCD16^high) monocyte subsets in 102 patients with early-onset OCD and in 47 healthy controls. Moreover, proinflammatory cytokine production (GM-CSF, IL-1β, IL-6, IL-8, and TNF-α) was measured by multiplex Luminex analysis in isolated monocyte cultures, in basal conditions, after exposure to lipopolysaccharide (LPS) to stimulate immune response or after exposure to LPS and the immunosuppressant dexamethasone.

RESULTS

OCD patients had significantly higher percentages of total monocytes and CD16+ monocytes than healthy controls, mainly due to an increase in the intermediate subset but also in the non-classical monocytes. Monocytes from OCD patients released higher amounts of GM-CSF, IL-1β, IL-6, IL-8, and TNF-α than healthy controls after exposure to LPS. However, there were no significant differences in basal cytokine production or the sensitivity of monocytes to dexamethasone treatment between both groups. Based on monocyte subset distribution and cytokine production after LPS stimulation, patients receiving psychoactive medications seem to have an intermediate inflammatory profile, that is, lower than non-medicated OCD individuals and higher than healthy controls.

CONCLUSIONS

These results strongly support the involvement of an enhanced proinflammatory innate immune response in the etiopathogenesis of early-onset OCD.

An expert opinion on PANDAS/PANS: highlights and controversies

OBJECTIVES

'Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections' (PANDAS) identified a unique subgroup of patients with abrupt onset of obsessive compulsive disorder (OCD) symptoms clinically related to Streptococcus infection and accompanied by neuropsychological and motor symptoms. After almost 20 years, PANDAS has not been accepted as distinct disorder and new criteria for paediatric acute-onset neuropsychiatric syndrome (PANS) have been replaced it, highlighting the fact that several agents rather than only Streptococcus might be involved.

METHODS

Extensive review of the PANDAS/PANS literature was performed on PubMed.

RESULTS

Although antibiotics have been reported to be effective for acute and prophylactic phases in several uncontrolled studies and non-steroidal anti-inflammatory drugs (NSAID) are used during exacerbations, clinical multicenter trials are still missing. Selective serotonin reuptake inhibitors (SSRIs) and cognitive behavioural therapy (CBT) are still the first line of recommendation for acute onset OCD spectrum. Immunological therapies should be restricted to a few cases.

CONCLUSIONS

While PANDAS has found no confirmation as a distinct syndrome, and it is not presented in DSM-5, patients with acute onset OCD spectrum, neurocognitive and motor symptoms should be evaluated for inflammatory, infective, immunological and metabolic abnormalities with a comprehensive diagnostic algorithm.

Biological markers for anxiety disorders, OCD and PTSD: A consensus statement. Part II: Neurochemistry, neurophysiology and neurocognition

OBJECTIVE

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part II) summarises findings on potential biomarkers in neurochemistry (neurotransmitters such as serotonin, norepinephrine, dopamine or GABA, neuropeptides such as cholecystokinin, neurokinins, atrial natriuretic peptide, or oxytocin, the HPA axis, neurotrophic factors such as NGF and BDNF, immunology and CO2 hypersensitivity), neurophysiology (EEG, heart rate variability) and neurocognition. The accompanying paper (Part I) focuses on neuroimaging and genetics.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high quality research has accumulated that should improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

The usefulness of immunotherapy in pediatric neurodegenerative disorders: A systematic review of literature data

Immunotherapeutic strategies to treat neurodegenerative disorders have inspired the scientific community. The aim of our review is to address the translational aspects of neuroimmunology to describe the efficacy of immunotherapy in the treatment of pediatric neurodegenerative disorders. In the studies we analyzed IVIG were found to be efficient in the treatment of post-streptococcal neurodegenerative disorders, even if in PANDAS, plasma-exchange (PE) showed a higher efficiency. IVIG were also successfully used in ADEM and Guillan-Barré syndrome. In Sydenham Chorea the use of methylprednisolone was found in most cases as efficient as IVIG, while in Tourette's Syndrome, Colecoxib was successfully used in one patient. Pediatric Multiple Sclerosis seems to respond better to immunosuppressant agents (Mitoxantrone, Cyclophosphamide, Natalizumab), as well as Neuromyelitis optica (Rituximab, Mycofenolate). The importance of this review relies in the attempt to draw standardized guidelines for immunotherapy in pediatric neurodegeneratve disorders.

"WHAT'S BUGGING THE GUT IN OCD?" A REVIEW OF THE GUT MICROBIOME IN OBSESSIVE-COMPULSIVE DISORDER

The gut microbiome has become a topic of major interest as of late, with a new focus specifically on psychiatric disorders. Recent studies have revealed that variations in the composition of the gut microbiota may influence anxiety and mood and vice versa. Keeping the concept of this bidirectional "microbiota-gut-brain" axis in mind, this review aims to shed light on how these findings may also be implicated in obsessive-compulsive disorder (OCD); potentially outlining a novel etiological pathway of interest for future research in the field.

CNS autoimmune disease after Streptococcus pyogenes infections: animal models, cellular mechanisms and genetic factors

Streptococcus pyogenes infections have been associated with two autoimmune diseases of the CNS: Sydenham's chorea (SC) and Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus infections (PANDAS). Despite the high frequency of pharyngeal streptococcus infections among children, only a small fraction develops SC or PANDAS. This suggests that several factors in combination are necessary to trigger autoimmune complications: specific S. pyogenes strains that induce a strong immune response toward the host nervous system; genetic susceptibility that predispose children toward an autoimmune response involving movement or tic symptoms; and multiple infections of the throat or tonsils that lead to a robust T_h17 cellular and humoral immune response when untreated. In this review, we summarize the evidence for each factor and propose that all must be met for the requisite neurovascular pathology and behavioral deficits found in SC/PANDAS.

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.

Five youth with pediatric acute-onset neuropsychiatric syndrome of differing etiologies

BACKGROUND

Pediatric acute-onset neuropsychiatric syndrome (PANS) is diagnosed by the abrupt onset of new obsessive compulsive disorder (OCD) or food-restricting symptoms, and at least two of a variety of other neuropsychiatric symptoms. Detailed clinical presentation of youth with this condition has not yet been provided in the literature.

METHODS

We review the clinical charts of five youth meeting criteria for PANS in our PANS Clinic. These five patients were selected for differing underlying causes thought to be driving an inflammatory response that appeared to impact psychiatric symptoms.

RESULTS

Five youth with varying potential etiologies impacting neuropsychiatric symptoms were identified. These youth were from 8 to 18 years old at the onset of their PANS illness, and had bacterial, autoimmune, and unknown etiologies. Treatment directed at presumed etiologies ranged from antibiotics to intravenous gamma globulin (IVIG) to other immunomodulatory regimens, and appeared to improve the psychiatric illness.

CONCLUSIONS

Youth with PANS may present in differing ways, with psychiatric and physical symptoms overlapping with inflammatory or infectious diseases, pain syndromes, and other psychiatric diagnoses. Patients' psychiatric symptoms may respond to treatments targeting the underlying cause of physical illness. Faced with a pediatric patient demonstrating the abrupt onset or exacerbation of psychiatric and physical symptoms, clinicians should consider PANS in their differential diagnosis.

Multidisciplinary clinic dedicated to treating youth with pediatric acute-onset neuropsychiatric syndrome: presenting characteristics of the first 47 consecutive patients

BACKGROUND

Abrupt, dramatic onset obsessive-compulsive disorder (OCD) and/or eating restriction with at least two coinciding symptoms (anxiety, mood dysregulation, irritability/aggression/oppositionality, behavioral regression, cognitive deterioration, sensory or motor abnormalities, or somatic symptoms) defines pediatric acute-onset neuropsychiatric syndrome (PANS). Descriptions of clinical data in such youth are limited.

METHODS

We reviewed charts of 53 consecutive patients evaluated in our PANS Clinic; 47 met PANS symptom criteria but not all met the requirement for "acute onset." Patients meeting full criteria for PANS were compared with patients who had a subacute/insidious onset of symptoms.

RESULTS

Nineteen of 47 (40%) patients in the study had acute onset of symptoms. In these patients, autoimmune/inflammatory diseases and psychiatric disorders were common in first-degree family members (71% and 78%, respectively). Most acute-onset patients had a relapsing/remitting course (84%), prominent sleep disturbances (84%), urinary issues (58%), sensory amplification (66%), gastrointestinal symptoms (42%), and generalized pain (68%). Inflammatory back pain (21%) and other arthritis conditions (28%) were also common. Suicidal and homicidal thoughts and gestures were common (44% and 17%, respectively) as were violent outbursts (61%). Group A streptococcus (GAS) was the most commonly identified infection at onset (21%) and during flares (74%). Rates of the above-mentioned characteristics did not differ between the acute-onset group and the subacute/insidious-onset groups. Low levels of immunoglobulins were more common in the subacute/insidious-onset group (75%) compared with the acute-onset group (22%), but this was not statistically significant (p=0.06).

CONCLUSIONS

In our PANS clinic, 40% of patients had acute onset of symptoms. However, those with and without acute onset of symptoms had similar symptom presentation, rates of inflammatory conditions, somatic symptoms, and violent thoughts and behaviors. GAS infections were the most commonly identified infection at onset and at symptom flares. Because of the wide variety of medical and psychiatric symptoms, youth with PANS may require a multidisciplinary team for adequate care management.

Evaluation of autoimmune phenomena in patients with pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS)

The pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) are basically characterized by obsessive-compulsive symptoms and/or tics triggered by group-A beta-hemolytic Streptococcus infections. Poor data are available about the clear definition of PANDAS's autoimmune origin. The aim of our study was to evaluate the prevalence of autoimmune phenomena, including thyroid function abnormalities, specific celiac disease antibodies, and positivity of organ- or nonorgan-specific autoantibodies in a large cohort of Caucasian children and adolescents with PANDAS. Seventy-seven consecutive patients (59 males, 18 females; mean age 6.3±2.5 years, range 2.0-14.5 years) strictly fulfilling the clinical criteria for PANDAS diagnosis were recruited. In all subjects we evaluated serum concentrations of free-T3, free-T4, thyrotropin, and the following auto-antibodies: anti-thyroperoxidase, anti-thyroglobulin, anti-thyrotropin receptor, anti-gliadin, anti-endomysium, anti-tissue transglutaminase, anti-nuclear, anti-smooth muscle, anti-extractable nuclear antigens, anti-phospholipid, plus lupus-like anticoagulant. The results were compared with those obtained from 197 age- and sex-matched healthy controls (130 males, 67 females; mean age 6.8±2.9 years, range 2.3-14.8 years). The frequencies of subclinical (3.8% vs 3.6%) and overt hypothyroidism (1.2% vs 0%), autoimmune thyroiditis (2.46% vs 1.14%), celiac disease (1.2% vs 0.05%), and positivity of organ- and nonorgan-specific autoantibodies (5.1% vs 4.8%) were not statistically significant between patients with PANDAS and controls. Evaluating the overall disease duration, we did not observe any significant difference between patients with (3.4±2.15 years) and without (3.4±2.89 years) autoimmune abnormalities. However, PANDAS patients with autoimmune diseases or positivity for any organ- and nonorgan-specific antibodies showed significantly higher anti-streptolysin O and anti-DNAse B titers, as well as a history of more frequent throat infections than controls (p<0.0001). Abnormalities of thyroid function and thyroid autoimmune diseases, as well as the association with celiac disease or organ- and nonorgan-specific autoimmunity seem not more frequent in children and adolescents with PANDAS than in healthy controls. A potential relationship between autoimmunity and PANDAS should be assessed further in larger studies. Children and adolescents with PANDAS should not be actually screened for thyroid function, celiac disease and/or autoimmune diseases.

Anti-basal ganglia antibodies in primary obsessive-compulsive disorder: systematic review and meta-analysis

BACKGROUND

Autoimmune-mediated basal ganglia dysfunction is implicated in the pathophysiology of neuropsychiatric disorders commonly manifesting with obsessive-compulsive features (e.g. Sydenham chorea). The relationship between autoimmunity and primary obsessive-compulsive disorder (OCD), however, is less clear.

AIMS

To pool data on serum and cerebrospinal fluid (CSF) anti-basal ganglia antibody (ABGA) positivity in primary OCD (without neurological or autoimmune comorbidity) relative to controls or neuropsychiatric disorders previously associated with increased odds of ABGA positivity.

METHOD

We performed electronic database and hand-searches for studies meeting pre-specified eligibility criteria from which we extracted data using a standardised form. We calculated pooled estimates of ABGA positivity using a random-effects model.

RESULTS

Seven case-control studies totalling 844 participants met the eligibility criteria. Meta-analysis showed that a significantly greater proportion of those with primary OCD were ABGA seropositive compared with various controls (odds ratio (OR) = 4.97, 95% CI 2.88-8.55, P<0.00001). This effect was not associated with heterogeneity or publication bias, and remained significant after stratifying the analysis by age, gender, disease severity, illness duration, immunostaining methodology, study quality, publication type, kind of control group, and sample size. There were no significant differences in ABGA seropositivity for comparisons between primary OCD and Tourette syndrome, attention-deficit hyperactivity disorder or paediatric acute-onset neuropsychiatric syndrome.

RESULTS

of one study testing CSF samples showed that a significantly greater proportion of participants with primary OCD were ABGA CSF-positive compared with healthy controls (OR = 5.60, 95% CI 1.04-30.20, P = 0.045).

CONCLUSIONS

Odds of ABGA seropositivity are increased fivefold in primary OCD compared with controls, but are comparable to those associated with disorders previously associated with ABGA, providing circumstantial evidence of autoimmunity in a subset of those with primary OCD. Further experimental studies are needed to ascertain whether this relationship is causal.

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.

Neuroinflammation, neuroautoimmunity, and the co-morbidities of complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is associated with non-dermatomal patterns of pain, unusual movement disorders, and somatovisceral dysfunctions. These symptoms are viewed by some neurologists and psychiatrists as being psychogenic in origin. Recent evidence, however, suggests that an autoimmune attack on self-antigens found in the peripheral and central nervous system may underlie a number of CRPS symptoms. From both animal and human studies, evidence is accumulating that neuroinflammation can spread, either anterograde or retrograde, via axonal projections in the CNS, thereby establishing neuroinflammatory tracks and secondary neuroinflammatory foci within the neuraxis. These findings suggest that neuroinflammatory lesions, as well as their associated functional consequences, should be evaluated during the differential diagnosis of non-dermatomal pain presentations, atypical movement disorders, as well as other "medically unexplained symptoms", which are often attributed to psychogenic illness.

Association of genetic variations in X-ray repair cross-complementing group 1 and Tourette syndrome

BACKGROUND

X-ray repair cross-complementing group 1 (XRCC1) plays a central role in mammalian DNA repair process. The polymorphism rs25487 (Arg>Gln at codon 399) of this gene is common in Han Chinese population.

OBJECTIVES

The objective of this study was to analyze the association between this functional SNP of XRCC1 and Tourette syndrome (TS) in Han Taiwan Chinese population.

METHODS

Genotyping was performed by using PCR-RFLP method on 73 TS patients and 158 normal controls.

RESULTS

Our data indicated that genotype frequency of A/G polymorphism at codon 399 of the patients differed from the controls (P = 0.026, OR: 2.22, 95% CI: 1.22-4.03). The allele frequency analysis also showed significant differences with higher A allele frequency in patients (P = 0.015, OR: 1.70, 95% CI: 1.11-2.62).

CONCLUSION

Our study indicates that the functional SNP at codon 399 of XRCC1 is associated with TS development.

Theoretical and practical considerations behind the use of laboratory animals for the study of Tourette syndrome

In the present manuscript we review a substantial body of literature describing several pre-clinical animal models designed and developed with the purpose of investigating the biological determinants of Tourette syndrome (TS). In order to map the animal models onto the theoretical background upon which they have been devised, we first define phenomenological and etiological aspects of TS and then match this information to the available pre-clinical models. Thus, we first describe the characteristic symptoms exhibited by TS patients and then a series of hypotheses attempting to identify the multifactorial causes of TS. With respect to the former, we detail the phenomenology of abnormal repetitive behaviors (tics and stereotypies), obsessive-compulsive behaviors and aberrant sensory-motor gating. With respect to the latter, we describe both potential candidate vulnerability genes and environmental factors (difficult pregnancies, psychosocial stressors and infections). We then discuss how this evidence has been translated in pre-clinical research with respect to both dependent (symptoms) and independent (etiological factors) variables. Thus, while, on the one hand, we detail the methodologies adopted to measure abnormal repetitive and obsessive-compulsive behaviors, and sensory-motor gating, on the other hand, we describe genetic engineering studies and environmental modulations aimed at reproducing the proposed biological determinants in laboratory rodents. A special emphasis is placed upon "programming" events, occurring during critical stages of early development and exerting organizational delayed consequences. In the final section, we outline a heuristic model with the purpose of integrating clinical and pre-clinical evidence in the study of TS.

Neuroinflammation and psychiatric illness

Multiple lines of evidence support the pathogenic role of neuroinflammation in psychiatric illness. While systemic autoimmune diseases are well-documented causes of neuropsychiatric disorders, synaptic autoimmune encephalitides with psychotic symptoms often go under-recognized. Parallel to the link between psychiatric symptoms and autoimmunity in autoimmune diseases, neuroimmunological abnormalities occur in classical psychiatric disorders (for example, major depressive, bipolar, schizophrenia, and obsessive-compulsive disorders). Investigations into the pathophysiology of these conditions traditionally stressed dysregulation of the glutamatergic and monoaminergic systems, but the mechanisms causing these neurotransmitter abnormalities remained elusive. We review the link between autoimmunity and neuropsychiatric disorders, and the human and experimental evidence supporting the pathogenic role of neuroinflammation in selected classical psychiatric disorders. Understanding how psychosocial, genetic, immunological and neurotransmitter systems interact can reveal pathogenic clues and help target new preventive and symptomatic therapies.

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.

Immunology, autoimmunity, and autoantibodies in Parkinson's disease

Recent revelations of immune alterations in Parkinson's disease have led to the convergence that an autoimmune mechanism may play a role in the etiopathogenesis of this neurodegenerative disease. In the current study, 77 Parkinson's disease patients and 77 matched healthy controls were analyzed for the presence of seven autoantibodies previously found to be associated with central nervous system manifestations namely: antineuronal-cells, anti-brain lysate, anti-dsDNA, anti-phosphatidylserine, anti-cardiolipin, anti-serotonin, and anti-melanocytes antibodies. Patients underwent systematic assessments of demographics, clinical, and biochemical manifestations. Three autoantibodies were found to be more prevalent among Parkinson's disease patients (antineuronal cells10.3% vs. 1.3%, p = 0.017; anti-brain lysate 9.1% vs. 1.3%, p = 0.032; anti-dsDNA 10.3% vs. 2.6%, p = 0.049). Clinical manifestations of Parkinson's disease, particularly dyskinesia and depression, were found to be associated with the presence of these autoantibodies.

Hyperpolarisation-activated cyclic nucleotide channel 4 (HCN4) involvement in Tourette's syndrome autoimmunity

OBJECTIVES

We previously found that antibodies in Tourette's syndrome (TS) patients' sera reacted with a 120 kDa protein from rat brain tissue. Here, we sought to identify this protein and determine if it was involved in TS pathogenesis.

METHODS

The 120 kDa protein was identified using immunoprecipitation, Western blotting, and mass spectrometry. ELISAs were used to quantify anti-120 kDa protein antibodies in serum of interest using samples from 32 TS patients, 47 patients with attention deficit hyperactivity disorder (ADHD) and 14 healthy controls. Involvement of the 120 kDa protein in TS was confirmed using co-localisation assays with GH3 cells. TS sera were micro-infused into SD rats' brain striatum and their stereotypical behaviours were monitored.

RESULTS

The brain protein was identified as hyperpolarisation-activated cyclic nucleotide channel 4 (HCN4). TS patients' sera contained significantly more anti-HCN4 antibodies than ADHD patient and control sera. After microinfusing TS serum, SD rats exhibited increased stereotyped tic behaviours, which were correlated with the amount of infused anti-HCN4 antibody.

CONCLUSIONS

Anti-HCN4 antibodies in the brain might contribute to the pathogenesis of tic symptoms in TS patients. However, further studies are needed to investigate the validity of this animal model of TS induced by microinfusing anti-HCN4 antibody.

Prevalence of anti-basal ganglia antibodies in adult obsessive-compulsive disorder: cross-sectional study

BACKGROUND

Symptoms of obsessive-compulsive disorder (OCD) have been described in neuropsychiatric syndromes associated with streptococcal infections. It is proposed that antibodies raised against streptococcal proteins cross-react with neuronal proteins (antigens) in the brain, particularly in the basal ganglia, which is a brain region implicated in OCD pathogenesis.

AIMS

To test the hypothesis that post-streptococcal autoimmunity, directed against neuronal antigens, may contribute to the pathogenesis of OCD in adults.

METHOD

Ninety-six participants with OCD were tested for the presence of anti-streptolysin-O titres (ASOT) and the presence of anti-basal ganglia antibodies (ABGA) in a cross-sectional study. The ABGA were tested for with western blots using three recombinant antigens; aldolase C, enolase and pyruvate kinase. The findings were compared with those in a control group of individuals with depression (n = 33) and schizophrenia (n = 17).

RESULTS

Positivity for ABGA was observed in 19/96 (19.8%) participants with OCD compared with 2/50 (4%) of controls (Fisher's exact test P = 0.012). The majority of positive OCD sera (13/19) had antibodies against the enolase antigen. No clinical variables were associated with ABGA positivity. Positivity for ASOT was not associated with ABGA positivity nor found at an increased incidence in participants with OCD compared with controls.

CONCLUSIONS

These findings support the hypothesis that central nervous system autoimmunity may have an aetiological role in some adults with OCD. Further study is required to examine whether the antibodies concerned are pathogenic and whether exposure to streptococcal infection in vulnerable individuals is a risk factor for the development of OCD.

Immunological markers in neurological disorders

Neurological dysfunction results from vascular, inflammatory, degenerative, neoplastic, metabolic or genetic causes. Of particular interest is a group of neurological symptoms thought to be linked to an underlying tumour, the so-called paraneoplastic syndromes. It is considered to be due to an attempt by the immune system to subjugate the growth of the tumour by triggering an antibody response against the neuronal antigens expressed by the neoplasm. The unfortunate consequence of this is an assault by the immune components on the nervous tissue, thereby rapidly precipitating a variety of neurological deficits. Every level of the nervous system is potentially vulnerable, with the disability being considered as irreversible due to the lack of regenerative capacity of the neurons. This phenomenon is rare, occurring at an approximate frequency of less than 1% of all tumours and often accompanied by the presence of specific high-titre autoantibodies in both the cerebrospinal fluid and blood. This group of antibodies are non-pathogenic markers for paraneoplastic neurological syndromes, which have expanded to almost 20 since the discovery, in 1986, of the first clinically relevant syndrome. More recently, a new generation of antineuronal antibodies against cell surface antigens, having a direct pathogenic role in causing the disease, has emerged to complement the existing repertoire. Neuronal antibodies are useful diagnostic markers of the brain disease and also, in some cases, may reveal an underlying malignancy, thus facilitating faster diagnosis and earlier treatment with consequently better prognosis.