Evaluation of basal ganglia and thalamic inflammation in children with pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection and tourette syndrome: a positron emission tomographic (PET) study using 11C-[R]-PK11195

A review of common influencing factors and possible mechanisms associated with allergic diseases complicating tic disorders in children

Over the past few decades, the incidence of childhood allergic diseases has increased globally, and their impact on the affected child extends beyond the allergy itself. There is evidence of an association between childhood allergic diseases and the development of neurological disorders. Several studies have shown a correlation between allergic diseases and tic disorders (TD), and allergic diseases may be an important risk factor for TD. Possible factors influencing the development of these disorders include neurotransmitter imbalance, maternal anxiety or depression, gut microbial disorders, sleep disturbances, maternal allergic status, exposure to tobacco, and environmental factors. Moreover, gut microbial disturbances, altered immunological profiles, and DNA methylation in patients with allergic diseases may be potential mechanisms contributing to the development of TD. An in-depth investigation of the relationship between allergic diseases and TD in children will be important for preventing and treating TD.

Prevalence of Neurological Soft Signs at Presentation in Pediatric Acute-Onset Neuropsychiatric Syndrome

Importance

Studies of brain imaging and movements during REM sleep indicate basal ganglia involvement in pediatric acute-onset neuropsychiatric syndrome (PANS). Characterizing neurological findings commonly present in patients with PANS could improve diagnostic accuracy.

Objective

To determine the prevalence of neurological soft signs which may reflect basal ganglia dysfunction (NSS-BG) in youth presenting with PANS and whether clinical characteristics of PANS correlate with NSS-BG. Design, Setting, and Participants: 135 new patients who were evaluated at the Stanford Children's Immune Behavioral Health Clinic between November 1, 2014 and March 1, 2020 and met strict PANS criteria were retrospectively reviewed for study inclusion. 16 patients were excluded because they had no neurological exam within the first three visits and within three months of clinical presentation.

Main Outcomes and Measures

The following NSS-BG were recorded from medical record review: 1) glabellar tap reflex, 2) tongue movements, 3) milkmaid's grip, 4) choreiform movements, 5) spooning, and 6) overflow movements. We included data from prospectively collected symptoms and impairment scales.

Results

The study included 119 patients: mean age at PANS onset was 8.2 years, mean age at initial presentation was 10.4 years, 55.5% were male, and 73.9% were non-Hispanic White. At least one NSS-BG was observed in 95/119 patients (79.8%). Patients had 2.1 NSS-BG on average. Patients with 4 or more NSS-BG had higher scores of global impairment (p=0.052) and more symptoms (p=0.008) than patients with 0 NSS-BG. There was no significant difference in age at visit or reported caregiver burden. On Poisson and linear regression, the number of NSS-BG was associated with global impairment (2.857, 95% CI: 0.092-5.622, p=0.045) and the number of symptoms (1.049, 95% CI: 1.018-1.082, p=0.002), but not age or duration of PANS at presentation.

Conclusions and Relevance

We found a high prevalence of NSS-BG in patients with PANS and an association between NSS-BG and disease severity that is not attributable to younger age. PANS may have a unique NSS-BG profile, suggesting that targeted neurological exams may support PANS diagnosis.

Psychometric Properties of the PANS 31-Item Symptom Rating Scale

Objectives: Pediatric acute-onset neuropsychiatric syndrome (PANS) is characterized by sudden onset of obsessive-compulsive disorder and/or eating restriction with associated neuropsychiatric symptoms from at least two of seven categories. The PANS 31-Item Symptom Rating Scale (PANS Rating Scale) was developed to identify and measure the severity of PANS symptoms. The objective of this study was to define the psychometric properties of the PANS Rating Scale. Methods: Children with PANS (N = 135) and their parents participated. Parents completed the PANS Rating Scale and other scales on Research Electronic Data Capture. The PANS Rating Scale includes 31 items that are rated on a Likert scale from 0 = none to 4 = extreme. Pearson's correlations were run between the PANS Total score and scores on the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS), Yale Global Tic Severity Scale (YGTSS), Modified Overt Aggression Scale (MOAS), Columbia Impairment Scale (CIS), PANS Global Impairment Score (GIS), and Children's Global Assessment Scale (CGAS). Results: Convergent validity was supported by significant correlations between the PANS Total and scores on the CY-BOCS, YGTSS, MOAS, CIS, GIS, and CGAS. The largest correlations were with measures of functional impairment: PANS Total and CIS (r = 0.81) and PANS Total and GIS (r = 0.74). Cronbach's alpha was 0.89 which demonstrates strong internal consistency of the 31 items. PANS Total score was significantly higher in children in a flare of their neuropsychiatric symptoms compared to children who were not in a flare. Conclusions: This study provides preliminary support for the PANS Rating Scale as a valid research instrument with good internal consistency. The PANS Rating Scale appears to be a useful measure for assessing children with PANS.

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) Syndrome: A 10-Year Retrospective Cohort Study in an Italian Centre of Pediatric Rheumatology

BACKGROUND

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) syndrome is a rare pediatric disorder consisting of a sudden onset of obsessive-compulsive disorder (OCD) and/or tics after a group A Streptococcus (GAS) infection.

METHODS

In the period between 2013 and 2023, 61 children presented to our Pediatric Rheumatology unit with a suspicion of PANDAS syndrome. Among these, a retrospective analysis was conducted, and 19 fulfilled the current classification criteria and were included in this study.

RESULTS

The male-to-female ratio was 14:5, the median age at onset was 7.0 (2.0-9.5) years, and the median age at diagnosis was 8.0 (3.0-10.4) years. The median follow-up period was 16.0 (6.0-72.0) months. Family and personal history were relevant in 7/19 and 6/19 patients. Tics were present in all patients. Details for motor tics were retrospectively available in 18/19 patients, with the eyes (11/18) and neck/head (10/18) being most often involved. Vocal tics were documented in 8/19, behavioral changes in 10/19, and OCD in 2/19. Regarding the therapeutic response, all patients responded to amoxicillin, 12/13 to benzathine benzylpenicillin, and 7/9 to azithromycin.

CONCLUSIONS

Our findings partially overlap with previous reports. Larger prospective studies are needed to improve treatment strategies and classification criteria.

An updated review of pediatric autoimmune neuropsychiatric disorders associated with Streptococcus/pediatric acute-onset neuropsychiatric syndrome, also known as idiopathic autoimmune encephalitis: What the allergist should know

BACKGROUND

Pediatric acute-onset neuropsychiatric syndrome, further subcategorized as pediatric autoimmune neuropsychiatric disorders associated with streptococcus, is a form of idiopathic autoimmune encephalitis (IAE). Poststreptococcal autoimmunity seen in Idiopathic autoimmune encephalitis manifests as various neuropsychiatric symptoms such as obsessive rituals, tics, anxiety, depression, and many others. Idiopathic autoimmune encephalitis has clinically heterogeneous phenotypes that make accurate diagnosing difficult, although diagnostic testing such as the Cunningham Panel increases the likelihood of finding effective treatments. Current recommended treatments include psychiatric medication, behavioral intervention, antibiotics, anti-inflammatory therapy, and immunomodulating therapy.

OBJECTIVE

To provide an updated review on the diagnosis, management, and treatment of pediatric autoimmune neuropsychiatric disorder associated with streptococcus and pediatric autoimmune neuropsychiatric syndrome, also referred to as IAE.

RESULTS

Information from 47 sources was used to outline current knowledge of IAE pathophysiology, clinical manifestations, and epidemiology, and to outline diagnostic recommendations and current treatment guidelines. Gaps in knowledge, in addition to current controversy, were also outlined to provide a thorough background of this condition and future needs for IAE research.

CONCLUSION

Owing to the complexity and variability in ways patients with IAE may present to the allergist/immunologist office, an interdisciplinary approach is imperative to provide patients with the best medical care. Still, more research is needed to further elucidate the mechanism(s) and optimal treatment algorithm for IAE to facilitate broader recognition and acceptance of this condition by the medical community.

Implication of microbiota gut-brain axis in the manifestation of obsessive-compulsive disorder: Preclinical and clinical evidence

Recent research has highlighted the key role of gut microbiota in the development of psychiatric disorders. The adverse impact of stress, anxiety, and depression has been well documented on the commensal gut microflora. Thus, therapeutic benefits of gut microbiota-based interventions may not be avoided in central nervous system (CNS) disorders. In this review, we outline the current state of knowledge of gut microbiota with respect to obsessive-compulsive disorder (OCD). We discuss how OCD-generated changes corresponding to the key neurotransmitters, hypothalamic-pituitary-adrenal axis, and immunological and inflammatory pathways are connected with the modifications of the microbiota-gut-brain axis. Notably, administration of few probiotics such as Lactobacillus rhamnosus (ATCC 53103), Lactobacillus helveticus R0052, Bifidobacterium longum R0175, Saccharomyces boulardii, and Lactobacillus casei Shirota imparted positive effects in the management of OCD symptoms. Taken together, we suggest that the gut microbiota-directed therapeutics may open new treatment approaches for the management of OCD.

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS): Myth or Reality? The State of the Art on a Controversial Disease

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) syndrome is one of the most controversial diseases in pediatric rheumatology. Despite first being described more than 25 years ago as the sudden and rapid onset of obsessive-compulsive disorder (OCD) and/or tic disorder symptoms as complications of a Group A beta-hemolytic Streptococcus (GAS) infection, precise epidemiological data are still lacking, and there are no strong recommendations for its treatment. Recent advances in the comprehension of PANDAS pathophysiology are largely attributable to animal model studies and the understanding of the roles of Ca++/calmodulin-dependent protein kinase (CaM kinase) II, disrupted dopamine release in the basal ganglia, and striatal cholinergic interneurons. The diagnosis of PANDAS should be made after an exclusion process and should include prepubescent children with a sudden onset of OCD and/or a tic disorder, with a relapsing/remitting disease course, a clear temporal association between GAS infection and onset or exacerbation of symptoms, and the association with other neurological abnormalities such as motoric hyperactivity and choreiform movements. Antibiotic medications are the primary therapeutic modality. Nonetheless, there is a paucity of randomized studies and validated data, resulting in a scarcity of solid recommendations.

Postinfectious Inflammation, Autoimmunity, and Obsessive-Compulsive Disorder: Sydenham Chorea, Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection, and Pediatric Acute-Onset Neuropsychiatric Disorder

Postinfectious neuroinflammation has been implicated in multiple models of acute-onset obsessive-compulsive disorder including Sydenham chorea (SC), pediatric acute-onset neuropsychiatric syndrome (PANS), and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS). These conditions are associated with a range of autoantibodies which are thought to be triggered by infections, most notably group A streptococci (GAS). Based on animal models using huma sera, these autoantibodies are thought to cross-react with neural antigens in the basal ganglia and modulate neuronal activity and behavior. As is true for many childhood neuroinflammatory diseases and rheumatological diseases, SC, PANS, and PANDAS lack clinically available, rigorous diagnostic biomarkers and randomized clinical trials. In this review article, we outline the accumulating evidence supporting the role neuroinflammation plays in these disorders. We describe work with animal models including patient-derived anti-neuronal autoantibodies, and we outline imaging studies that show alterations in the basal ganglia. In addition, we present research on metabolites, which are helpful in deciphering functional phenotypes, and on the implication of sleep in these disorders. Finally, we encourage future researchers to collaborate across medical specialties (e.g., pediatrics, psychiatry, rheumatology, immunology, and infectious disease) in order to further research on clinical syndromes presenting with neuropsychiatric manifestations.

Tourette syndrome and obsessive-compulsive disorder: A comprehensive review of structural alterations and neurological mechanisms

Currently, it is possible to study the pathogenesis of Tourette's syndrome (TS) in more detail, due to more advanced methods of neuroimaging. However, medical and surgical treatment options are limited by a lack of understanding of the nature of the disorder and its relationship to some psychiatric disorders, the most common of which is obsessive-compulsive disorder (OCD). It is believed that the origin of chronic tic disorders is based on an imbalance of excitatory and inhibitory influences in the Cortico-Striato-Thalamo-Cortical circuits (CSTC). The main CSTCs involved in the pathological process have been identified by studying structural and neurotransmitter disturbances in the interaction between the cortex and the basal ganglia. A neurotransmitter deficiency in CSTC has been demonstrated by immunohistochemical and genetic methods, but it is still not known whether it arises as a consequence of genetically determined disturbances of neuronal migration during ontogenesis or as a consequence of altered production of proteins involved in neurotransmitter production. The aim of this review is to describe current ideas about the comorbidity of TS with OCD, the involvement of CSTC in the pathogenesis of both disorders and the background of structural and neurotransmitter changes in CSTC that may serve as targets for drug and neuromodulatory treatments.

Clinicopathologic Characteristics of PANDAS in a Young Adult: A Case Report

Pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS) is an acute onset or exacerbation of neuropsychiatric symptoms following a group A streptococcus infection. It is believed to be a result of autoimmune response to streptococcal infection, but there is insufficient evidence to fully support this theory. Although this disease is primarily thought to be a disease of childhood, it is reported to occur also in adults. PANDAS is a well-defined clinical entity, but the neuropathology of this condition has not been established yet. We describe the clinical course of a 26-year-old female diagnosed with PANDAS. She committed suicide and her brain was biobanked for further studies. We examined the banked tissue and performed special stains, immunohistochemical, and immunofluorescence analyses to characterize the neuropathology of this condition. Histology of the temporal lobes, hippocampus, and basal ganglia shows mild gliosis and Alzheimer's type II astrocytes. Acute hypoxic ischemic changes were noted in hippocampus CA1 and CA2 areas. Immunostaining shows increased parenchymal/perivascular GFAP staining and many vessels with mild increases in CD3-, CD4-, and CD25-stained lymphocytes in the basal ganglia. The findings suggest that CD4- and CD25-positive T cells might have an important role in understanding the neuroinflammation and pathogenesis of this condition. The case represents the first neuropathological evaluation report for PANDAS.

Evaluation of C4 Gene Copy Number in Pediatric Acute Neuropsychiatric Syndrome

Pediatric acute-onset neuropsychiatric syndrome (PANS) is an abrupt-onset neuropsychiatric disorder. PANS patients have an increased prevalence of comorbid autoimmune illness, most commonly arthritis. In addition, an estimated one-third of PANS patients present with low serum C4 protein, suggesting decreased production or increased consumption of C4 protein. To test the possibility that copy number (CN) variation contributes to risk of PANS illness, we compared mean total C4A and total C4B CN in ethnically matched subjects from PANS DNA samples and controls (192 cases and 182 controls). Longitudinal data from the Stanford PANS cohort (n = 121) were used to assess whether the time to juvenile idiopathic arthritis (JIA) or autoimmune disease (AI) onset was a function of total C4A or C4B CN. Lastly, we performed several hypothesis-generating analyses to explore the correlation between individual C4 gene variants, sex, specific genotypes, and age of PANS onset. Although the mean total C4A or C4B CN did not differ in PANS compared to controls, PANS patients with low C4B CN were at increased risk for subsequent JIA diagnosis (hazard ratio = 2.7, p value = 0.004). We also observed a possible increase in risk for AI in PANS patients and a possible correlation between lower C4B and PANS age of onset. An association between rheumatoid arthritis and low C4B CN has been reported previously. However, patients with PANS develop different types of JIA: enthesitis-related arthritis, spondyloarthritis, and psoriatic arthritis. This suggests that C4B plays a role that spans these arthritis types.

Vitamin D status and tic disorder: a systematic review and meta-analysis of observational studies

Objective

Tic disorders (TD) are a common neurodevelopmental disorder, it can be divided into transient tic disorder (TTD), chronic motor or vocal tic disorder (CTD), and Tourette syndrome (TS). Our research is to evaluate the clinical relationship between tic disorders and vitamin D level in children.

Methods

Online databases, including CNKI, Wanfang, VIP, Cochrane Library, PubMed and Embase digital knowledge service platform, were checked up to June 2022 for relevant observational studies published in Chinese and English. A random-effects model was incorporated to summarize the study results. The RevMan5.3 software was used for meta-analysis.

Results

Out of 132 retrieved articles, 13 observational studies were eligible for inclusion in the systematic review and meta-analysis, comparing serum Vitamin D levels between children with TD and HC (healthy controls), including different subtypes of TD (TTD, CTD and TS). The results showed that the serum vitamin D levels in the TD group were lower than those in the HC group (MD = -6.64, 95% CI: -9.36 to -3.93, P < 0.001, Heterogeneity test: P < 0.001, I2 = 94%). There were no statistically significant differences in serum vitamin D levels between the TTD group and the CTD group (MD = 3.84, 95% CI: -0.59 to 8.26, P = 0.09, Heterogeneity test: P < 0.001, I2 = 90%), or between the CTD group and the TS group (MD = 1.06, 95% CI: -0.04 to 2.16, P = 0.0, Heterogeneity test: P = 0.54, I2 = 0%). However, there was a statistically significant difference in serum vitamin D levels between the TTD group and the TS group (MD = 5.24, 95% CI: 0.68-9.80, P = 0.02, Heterogeneity test: P < 0.001, I2 = 92%). The study also found a statistically significant difference in the ratio of male children between the TD group and the HC group (OR = 1.48, 95% CI: 1.07-2.03, P = 0.02, Heterogeneity test: P < 0.001, I2 = 74%), but no statistically significant difference in the age of children between the TD group and the HC group (OR = 0.46, 95% CI: -0.33 to 1.24, P = 0.25, Heterogeneity test: P < 0.001, I2 = 96%).

Conclusions

Our meta-analysis showed that the vitamin D level of children with TD was lower than that of healthy children. However, there was no difference between the subgroup. Due to the limitations of included studies in research design and diagnostic criteria, large samples, multi-center and high-quality studies are still needed for further analysis and confirmation.

Pediatric Acute-Onset Neuropsychiatric Syndrome: Current Perspectives

Pediatric acute-onset neuropsychiatric syndrome (PANS) features a heterogeneous constellation of acute obsessive-compulsive disorder (OCD), eating restriction, cognitive, behavioral and/or affective symptoms, often followed by a chronic course with cognitive deterioration. An immune-mediated etiology is advocated in which the CNS is hit by different pathogen-driven (auto)immune responses. This narrative review focused on recent clinical (ie, diagnostic criteria, pre-existing neurodevelopmental disorders, neuroimaging) and pathophysiological (ie, CSF, serum, genetic and autoimmune findings) aspects of PANS. We also summarized recent points to facilitate practitioners with the disease management. Relevant literature was obtained from PubMed database which included only English-written, full-text clinical studies, case reports, and reviews. Among a total of 1005 articles, 205 were pertinent to study inclusion. Expert opinions are converging on PANS as the effect of post-infectious events or stressors leading to "brain inflammation", as it is well-established for anti-neuronal psychosis. Interestingly, differentiating PANS from either autoimmune encephalitides and Sydenham's chorea or from alleged "pure" psychiatric disorders (OCD, tics, Tourette's syndrome), reveals several overlaps and more analogies than differences. Our review highlights the need for a comprehensive algorithm to help both patients during their acute distressing phase and physicians during their treatment decision. A full agreement on the hierarchy of each therapeutical intervention is missing owing to the limited number of randomized controlled trials. The current approach to PANS treatment emphasizes immunomodulation/anti-inflammatory treatments in association with both psychotropic and cognitive-behavioral therapies, while antibiotics are suggested when an active bacterial infection is established. A dimensional view, taking into account the multifactorial origin of psychiatric disorders, should suggest neuro-inflammation as a possible shared substrate of different psychiatric phenotypes. Hence, PANS and PANS-related disorders should be considered as a conceptual framework describing the etiological and phenotypical complexity of many psychiatric disorders.

Distinct Th17 effector cytokines differentially promote microglial and blood-brain barrier inflammatory responses during post-infectious encephalitis

Group A Streptococcus (GAS) infections can cause neuropsychiatric sequelae in children due to post-infectious encephalitis. Multiple GAS infections induce migration of Th17 lymphocytes from the nose into the brain, which are critical for microglial activation, blood-brain barrier (BBB) and neural circuit impairment in a mouse disease model. How endothelial cells (ECs) and microglia respond to GAS infections, and which Th17-derived cytokines are essential for these responses are unknown. Using single-cell RNA sequencing and spatial transcriptomics, we found that ECs downregulate BBB genes and microglia upregulate interferon-response, chemokine and antigen-presentation genes after GAS infections. Several microglial-derived chemokines were elevated in patient sera. Administration of a neutralizing antibody against interleukin-17A (IL-17A), but not ablation of granulocyte-macrophage colony-stimulating factor (GM-CSF) in T cells, partially rescued BBB dysfunction and microglial expression of chemokine genes. Thus, IL-17A is critical for neuropsychiatric sequelae of GAS infections and may be targeted to treat these disorders.

Integrated network pharmacology and experimental verification to explore the molecular mechanism of Jingxin Zhidong formula for treating Tic disorder

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese medicine formula, Jingxin Zhidong Formula (JXZDF) based on ancient amber powder has been prescribed to alleviate tic disorders (TD) according to our clinical practice for many years. However, the underlying molecular mechanisms remain largely unknown.

AIM OF STUDY

To explore the potential mechanism of JXZDF in the treatment of TD by using network pharmacology and experimental validation.

MATERIALS AND METHODS

The chemical components of JXZDF were detected and the potential pathway enrichment analyses were conducted based on network pharmacology. Finally, we performed cell viability assays and Western blotting on LPS-induced BV-2 cells, and subsequently performed behavioral tests and Western blotting in SD rats model for TD to explore the mechanism of JXZDF on TD.

RESULTS

By LC-ESI-MS/MS system and searching the databases, we identified 5 key compounds and 29 hub targets of JXZDF on TD. KEGG enrichment analysis showed that PI3K/AKT signaling pathway may be the key pathway for JXZDF on TD. The vitro experimental results proved that JXZDF can inhibit the phosphorylation of PI3K and AKT proteins on LPS-induced BV-2 cells. The animal experimental results indicated that JXZDF can effectively alleviate the stereotypic behavior and hyperactivity of the TD rats, and downregulated PI3K/AKT pathway to inhibit microglia activation in the hippocampus tissue.

CONCLUSION

This study indicated that JXZDF can change microglial activation and expression of proinflammatory mediators through the inactivation of PI3K/AKT signaling pathway, which may be one of the mechanisms of JXZDF in treating TD.

PANDAS/PANS in the COVID-19 Age: Autoimmunity and Epstein-Barr Virus Reactivation as Trigger Agents?

COVID-19 impacted the entire world's population, frequently resulting in long-lasting neuropsychiatric complications. Furthermore, social distancing, lockdowns and fear for one's personal health worsen individual psychological wellbeing, especially in children and adolescents. Herein, we discuss the results of studies that specifically reported data about the impact of the COVID-19 pandemic or infection on children with Pediatric Acute-Onset Neuropsychiatric Disorders (PANS). Furthermore, we present the cases of five adolescents with PANS whose symptomatology increased following SARS-CoV-2 infection. What emerged from this study was that COVID-19 resulted in the exacerbation of obsessions, tics, anxiety and mood symptoms and decreased wellbeing. Moreover, new symptoms, as well as new PANS cases, are reported to have arisen after COVID-19 infection. Here, we hypothesize that the pathogenic mechanisms of silent viruses, such as the Epstein-Barr virus, are related to neuroinflammation, immune responses and reactivation, with additional roles played by social-isolation-related inflammatory processes. The discussion of PANS, which represents a model of immune-mediated neuropsychiatric manifestations, is particularly relevant, with the aim of uncovering the mechanisms that lead to neuropsychiatric Post-Acute COVID-19 Syndrome (PACS). Prospects for future studies and treatment implications are discussed.

Neuroinflammation in Obsessive-Compulsive Disorder: Sydenham Chorea, Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections, and Pediatric Acute Onset Neuropsychiatric Syndrome

Sydenham chorea (SC), pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) and pediatric acute-onset neuropsychiatric syndrome (PANS) are postinfectious neuroinflammatory diseases that involve the basal ganglia and have obsessive-compulsive disorder as a major manifestation. As is true for many childhood rheumatological diseases and neuroinflammatory diseases, SC, PANDAS and PANS lack clinically available, rigorous diagnostic biomarkers and randomized clinical trials. Research on the treatment of these disorders depend on three complementary modes of intervention including: treating the symptoms, treating the source of inflammation, and treating disturbances of the immune system. Future studies should aim to integrate neuroimaging, inflammation, immunogenetic, and clinical data (noting the stage in the clinical course) to increase our understanding and treatment of SC, PANDAS, PANS, and all other postinfectious/immune-mediated behavioral disorders.

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.

Immunology and microbiome: Implications for motor systems

Immune-inflammatory mechanisms seem to play a relevant role in neurodegenerative disorders affecting motor systems, particularly Parkinson's disease, where activity changes in inflammatory cells and evidence of neuroinflammation in experimental models and patients is available. Amyotrophic lateral sclerosis is also characterized by neuroinflammatory changes that involve primarily glial cells, both microglia and astrocytes, as well as systemic immune dysregulation associated with more rapid progression. Similarly, the exploration of gut dysbiosis in these two prototypical neurodegenerative motor disorders is advancing rapidly. Altered composition of gut microbial constituents and related metabolic and putative functional pathways is supporting a pathophysiological link that is currently explored in preclinical, germ-free animal models. Less compelling, but still intriguing, evidence suggests that motor neurodevelopmental disorders, e.g., Tourette syndrome, are associated with abnormal trajectories of maturation that include also immune system development. Microglia has a key role also in these disorders, and new therapeutic avenues aiming at its modulation are exciting prospects. Preclinical and clinical research on the role of gut dysbiosis in Tourette syndrome and related behavioral disorders is still in its infancy, but early findings support the rationale to delve deeper into its contribution to neural and immune maturation abnormalities in its spectrum.

Microglial WNT5A supports dendritic spines maturation and neuronal firing

There is increasing evidence showing that microglia play a critical role in mediating synapse formation and spine growth, although the molecular mechanism remains elusive. Here, we demonstrate that the secreted morphogen WNT family member 5A (WNT5A) is the most abundant WNT expressed in microglia and that it promotes neuronal maturation. Co-culture of microglia with Thy1-YFP+ differentiated neurons significantly increased neuronal spine density and reduced dendritic spine turnover rate, which was diminished by silencing microglial Wnt5a in vitro. Co-cultured microglia increased post-synaptic marker PSD95 and synaptic density as determined by the co-localization of PSD95 with pre-synaptic marker VGLUT2 in vitro. The silencing of Wnt5a expression in microglia partially reduced both PSD95 and synaptic densities. Co-culture of differentiated neurons with microglia significantly enhanced neuronal firing rate as measured by multiple electrode array, which was significantly reduced by silencing microglial Wnt5a at 23 days differentiation in vitro. These findings demonstrate that microglia can mediate spine maturation and regulate neuronal excitability via WNT5A secretion indicating possible pathological roles of dysfunctional microglia in developmental disorders.

Group Psychotherapy for Parents of Youth with Pediatric Acute-Onset Neuropsychiatric Syndrome

Parents of children with diagnoses of Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) and Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infections (PANDAS) may experience significant psychological distress related to their child's severe and relapsing illness and challenges with the traumatic nature of its treatment. No manualized or studied psychological interventions specifically for parents of youth with PANS have existed prior to this study. In this pilot study, we assessed the feasibility, satisfaction, and treatment fidelity of a brief 9-session group therapy intervention for parents based on principles of trauma-focused cognitive behavior therapy (CBT). We hypothesized that, if initially elevated, symptoms of depression, anxiety, and trauma would decrease and participants' utilization of positive coping mechanisms would increase post-intervention. We adapted an existing evidence-based group intervention developed for parents of children with premature infants to target sources of stress and coping in parents of children with PANS. Ten parents participated in the study. The 9-session intervention used a combination of techniques that included cognitive restructuring, coping skills, self-care, and a trauma narrative to address psychological stress, trust, grief, and unwanted emotions. Outcome measures included parental symptoms of anxiety, depression, and posttraumatic stress disorder (PTSD), as well as rating of parental satisfaction with the intervention. The treatment was feasible and deliverable with high fidelity. The intervention was rated as useful and satisfactory by parents (overall average usefulness of 4.54 and satisfaction of 4.71 out of 5.0). Elevated symptoms of PTSD and depression decreased with large effect sizes (Cohen's d = 1.42 and Cohen's d = 1.38, respectively). Participating parents demonstrated significantly more active coping and acceptance behaviors and stances. A brief 9-session group therapy intervention based on principles of trauma-focused CBT was found to be effective in reducing symptoms of psychological distress in parents of children with PANS.

Jing-an oral liquid alleviates Tourette syndrome via the NMDAR/MAPK/CREB pathway in vivo and in vitro

CONTEXT

Jing-an oral liquid (JA) is a Chinese herbal formula used in the treatment of Tourette syndrome (TS); however, its mechanism is unclear.

OBJECTIVE

To investigate the effects of JA on amino acid neurotransmitters and microglia activation in vivo and in vitro.

MATERIALS AND METHODS

Sixty male Sprague-Dawley rats were divided into a control group and 5 TS groups. TS was induced in rats with intraperitoneal injection of 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (1 mg/kg) and in BV2 cells with lipopolysaccharide. Control and model rats were administered saline, whereas treatment groups were administered JA (5.18, 10.36, or 20.72 g/kg) or tiapride (a benzamide, 23.5 mg/kg) by gavage once daily for 21 days. Stereotypic behaviour was tested. The levels of N-methyl-d-aspartate receptor (NMDAR)/mitogen-activated protein kinase/cAMP response element-binding protein (CREB)-related proteins in striatum and BV2 cells were measured via western blots. CD11b and IBa1 levels were also measured. Ultra-high-performance liquid-chromatography was used to determine γ-aminobutyric acid (GABA), glutamic acid (Glu), and aspartic acid (ASP) levels.

RESULTS

JA markedly alleviated the stereotype behaviour (25.92 ± 0.35 to 13.78 ± 0.47) in rats. It also increased NMDAR1 (0.48 ± 0.09 to 0.67 ± 0.08; 0.54 ± 0.07 to 1.19 ± 0.18) expression and down-regulated the expression of p-ERK, p-JNK, p-P38, and p-CREB in BV2 cells and rat striatum. Additionally, Glu, ASP, GABA, CD11b, and IBa1 levels were significantly decreased by JA.

DISCUSSION AND CONCLUSIONS

JA suppressed microglia activation and regulated the levels of amino acid neurotransmitters, indicating that it could be a promising therapeutic agent for TS.

Sex and Aggression Characteristics in a Cohort of Patients with Pediatric Acute-Onset Neuropsychiatric Syndrome

Objective: This study describes for the first time the characteristics by sex of patients with Pediatric Acute-onset Neuropsychiatric Syndrome (PANS), including clinical phenotype, treatment, and psychosocial aspects of disease. Methods: This cross-sectional study included 205 consecutive community patients evaluated between January 1, 2012 and March 30, 2019 and compared 87 females with 118 males. Our primary hypothesis was that males would display more aggression, as measured by the Modified Overt Aggression Scale (MOAS) and would be treated with immunotherapy earlier than females. The MOAS began to be administered 5 years into the study period, and 57 of the 205 families completed the MOAS for this study. Results: Our analysis revealed that males had a higher median MOAS score in the first year of clinic when compared with females (median 11, interquartile range [IQR] [4-24] vs. median 3, IQR [1-9]; p = 0.03) and a higher median subscore for physical aggression (median 4, IQR [0-12] vs. median 0, IQR [0-8]; p = 0.05). The median time from PANS symptom onset to first administration of immunotherapy, which did not include nonsteroidal anti-inflammatory drugs or short bursts of oral steroids, was 6.9 years for females and 3.7 years for males (p = 0.20). The two groups did not differ significantly in age of PANS onset, time from onset to clinic entry, other psychiatric symptom measures, or laboratory markers of inflammation. Conclusion: Among patients with PANS, males exhibit more aggressive behavior when compared with females, which may advance the decision to treat with immunotherapy. Scores that capture a more global level of functioning show that despite there being a higher level of aggression in males, female patients with PANS have similar levels of overall impairment.

Pediatric Autoimmune Neuropsychiatric Disorders Associated With Group A Streptococci: Etiopathology and Diagnostic Challenges

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) have attracted a lot of interest and discussion since it was originally characterized in 1998. The role of streptococcal infection in children with abrupt-onset obsessive-compulsive disorder (OCD) and new-onset tics, the natural history of this entity, and the role of symptomatic and disease-modifying therapies, such as antibiotics, immunotherapy, and psychoactive drugs, are still unresolved issues. Alternative therapies for acute-onset OCD have been developed based on this postulated pathophysiology, including antibiotics and immunomodulatory therapy. The literature on PANDAS therapy is varied but there is no clinical consensus on the treatment of choice.

While there is no convincing evidence for the autoimmune rationale for PANDAS, given the increased attention to this entity and the apparent growth in usage of this diagnostic category, it is critical to address concerns about the condition's diagnosis, treatment, and pathogenesis.

We conducted a multi-language literature search on Medline, Cochrane, Embase, and Google Scholar for a period spanning until October 2021. The following search strings and Medical Subject Heading (MeSH) terms were used: “PANDAS,” “Group A Streptococcus,” “OCD,” and “tics.” We explored the literature on PANDAS in terms of its epidemiology, pathophysiology, the role of group A streptococcal infection, associated complications, and prophylactic and treatment modalities.

We examined current working definitions of PANDAS, analyzed differential diagnoses, and published pieces of evidence for therapies associated with this entity, with a view to proposing a therapeutic strategy for children with acute symptoms that meet PANDAS criteria, in this review article.

A crosstalk between gut and brain in sepsis-induced cognitive decline

BACKGROUND

Sepsis is a potentially fatal disease characterized by acute organ failure that affects more than 30 million people worldwide. Inflammation is strongly associated with sepsis, and patients can experience impairments in memory, concentration, verbal fluency, and executive functioning after being discharged from the hospital. We hypothesize that sepsis disrupts the microbiota-gut-brain axis homeostasis triggering cognitive impairment. This immune activation persists during treatment, causing neurological dysfunction in sepsis survivors.

METHODS

To test our hypothesis, adult Wistar rats were subjected to cecal-ligation and perforation (CLP) or sham (non-CLP) surgeries. The animals were subjected to the [11C]PBR28 positron emission tomography (PET)/computed tomography (CT) imaging at 24 h and 10 days after CLP and non-CLP surgeries. At 24 h and 10 days after surgery, we evaluated the gut microbiome, bacterial metabolites, cytokines, microglia, and astrocyte markers. Ten days after sepsis induction, the animals were subjected to the novel object recognition (NOR) and the Morris water maze (MWM) test to assess their learning and memory.

RESULTS

Compared to the control group, the 24-h and 10-day CLP groups showed increased [11C]PBR28 uptake, glial cells count, and cytokine levels in the brain. Results show that sepsis modulates the gut villus length and crypt depth, alpha and beta microbial diversities, and fecal short-chain fatty acids (SCFAs). In addition, sepsis surviving animals showed a significant cognitive decline compared with the control group.

CONCLUSIONS

Since several pharmacological studies have failed to prevent cognitive impairment in sepsis survivors, a better understanding of the function of glial cells and gut microbiota can provide new avenues for treating sepsis patients.

Children With PANS May Manifest POTS

Objectives

Pediatric acute-onset neuropsychiatric syndrome (PANS) is characterized by an abrupt-onset of severe psychiatric symptoms including OCD, anxiety, cognitive difficulties, and sleep issues which is thought to be a post-infection brain inflammatory disorder. We observed postural orthostatic tachycardia syndrome (POTS) which resolved with immunomodulation in a patient with Pediatric acute-onset neuropsychiatric syndrome (PANS). Here, we aim to present a case of POTS and to examine the prevalence of (POTS) in our PANS cohort, and compare the clinical characteristics of patients with and without POTS.

Study Design

We conducted this cohort study of patients meeting PANS criteria who had at least three clinic visits during the study period. We included data from prospectively collected questionnaires and medical record review. We present a case followed by statistical comparisons within our cohort and a Kaplan-Meier analysis to determine the time-dependent risk of a POTS diagnosis.

Results

Our study included 204 patients: mean age of PANS onset was 8.6 years, male sex (60%), non-Hispanic White (78%). Evidence of POTS was observed in 19/204 patients (9%) with 5/19 having persistent POTS defined as persistent abnormal orthostatic vitals, persistent POTS symptoms, and/or continued need for pharmacotherapy for POTS symptoms for at least 6 months). In this PANS cohort, patients with POTS were more likely to have comorbid joint hypermobility (63 vs 37%, p = 0.04), chronic fatigue (42 vs 18%, p = 0.03), and a family history of chronic fatigue, POTS, palpitations and syncope. An unadjusted logistic regression model showed that a PANS flare (abrupt neuropsychiatric deterioration) was significantly associated with an exacerbation of POTS symptoms (OR 3.3, 95% CI 1.4–7.6, p < 0.01).

Conclusions

Our study describes a high prevalence of POTS in patients with PANS (compared to the general population) and supports an association between POTS presentation and PANS flare within our cohort.

Pediatric neuropsychiatric syndromes associated with infection and microbiome alterations: clinical findings, possible role of the mucosal epithelium, and strategies for the development of new animal models

INTRODUCTION

: Subsets of pediatric obsessive-compulsive disorder (OCD) and autism spectrum disorder (ASD) respectively have been associated with respiratory tract infections and alterations in the intestinal microbiome. Pediatric Acute-onset Neuropsychiatric Syndromes (PANS) refers to the sudden onset of neuropsychiatric symptoms that are triggered by several different infectious and non-infectious factors. Clinical studies and animal modeling are consistent with the proposal that inflammation plays an important etiological role in PANS, as well as in ASD associated with gut dysbiosis.

AREAS COVERED

The authors provide an overview of clinical studies of PANS and ASD associated with gastrointestinal symptoms, as well as the current strategies for studying these syndromes in rodent models. Finally, the authors highlight similarities between these syndromes that may provide clues to common etiological mechanisms.

EXPERT OPINION

Although data from existing animal models are consistent with an important role for anti-neuronal antibodies in PANS triggered by GAS infection, we lack models for identifying pathophysiological mechanisms of PANS associated with other infectious and non-infectious triggers. The authors propose a strategy for developing such models that incorporates known vulnerability and triggering factors for PANS into the modeling process. This novel strategy should expand our understanding of the pathophysiology of PANS, as well as facilitate the development of new pharmacological treatments for PANS and related syndromes.

Cognitive, Graphomotor, and Psychosocial Challenges in Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections (PANDAS)

OBJECTIVES

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) is characterized by the sudden onset of obsessive-compulsive disorder (OCD) and other neurobehavioral symptoms following group A streptococcal infection. The cardinal neuropsychiatric symptoms are believed to reflect an aberrant autoimmune or inflammatory response that may selectively disrupt basal ganglia function. The investigators examined whether neuropsychological skills associated with frontostriatal networks (executive functions and motor skills) are affected in patients with PANDAS following resolution of acute symptoms and the degree to which there are persistent social, emotional, and academic difficulties.

METHODS

Twenty-seven patients ages 6-14 years (mean age=9.63 years [SD=1.78]; male, N=22) completed neuropsychological testing as part of routine clinical care. Performances on measures of intellectual ability, executive function, motor skills, and academic skills are reported, as well as parent-reported emotional, behavioral, and social skills.

RESULTS

On neuropsychological measures, patients exhibited average intellectual functioning with relative and mild difficulties in skills supporting cognitive efficiency, including attentional regulation, inhibitory control, and processing speed. Dexterity was normal but graphomotor skills were reduced. Core reading, math, and writing skills were within expectations, but reading and math fluency were reduced, and the majority of patients received special education services or accommodations. Parents reported high levels of concern about anxiety, depression, inattention, hyperactivity, and social skills.

CONCLUSIONS

These findings indicated relative difficulties with aspects of executive and motor functions. Although evaluations were performed following the resolution of acute symptoms, ongoing and significant academic difficulties and emotional, behavioral, and social concerns were targets for clinical intervention and support.

Transcriptome-wide association study reveals increased neuronal FLT3 expression is associated with Tourette's syndrome

Tourette's Syndrome (TS) is a neurodevelopmental disorder that is characterized by motor and phonic tics. A recent TS genome-wide association study (GWAS) identified a genome-wide significant locus. However, determining the biological mechanism of GWAS signals remains difficult. To characterize effects of expression quantitative trait loci (eQTLs) in TS and understand biological underpinnings of the disease. Here, we conduct a TS transcriptome-wide association study (TWAS) consisting of 4819 cases and 9488 controls. We demonstrate that increased expression of FLT3 in the dorsolateral prefrontal cortex (DLPFC) is associated with TS. We further show that there is global dysregulation of FLT3 across several brain regions and probabilistic causal fine-mapping of the TWAS signal prioritizes FLT3 with a posterior inclusion probability of 0.849. After, we proxy the expression with 100 lymphoblastoid cell lines, and demonstrate that TS cells has a 1.72 increased fold change compared to controls. A phenome-wide association study also points toward FLT3 having links with immune-related pathways such as monocyte count. We further identify several splicing events in MPHOSPH9, CSGALNACT2 and FIP1L1 associated with TS, which are also implicated in immune function. This analysis of expression and splicing begins to explore the biology of TS GWAS signals.

Neuroinflammation in a Rat Model of Tourette Syndrome

Objective

Tourette syndrome (TS) is a group of childhood-onset chronic neuropsychiatric disorders characterized by tics, i.e., repetitive, sudden, and involuntary movements or vocalizations, which is often associated with various psychopathological and/or behavioral comorbidities, including attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, depression, and sleep disorders and have a worse prognosis. The mechanism of TS is still not clear. The relationship between immune activation, neuroinflammation, and neuropsychiatric disorders has attracted much attention in the past two decades. To explore the underlying mechanism in TS, the relationship between neuroinflammation and behavioral alterations in TS rats was investigated in this study.

Methods

A total of 36 Sprague-Dawley male rats were divided into three groups randomly as follows: the TS, control (CON), and drug intervention groups. The TS rat group was treated with haloperidol (Hal) (the TS + Hal group). The TS rat model was established using 3,3-iminodipropionitrile (IDPN), which is a well-known animal model of TS. The behavioral syndromes, brain tissue cytokines, like interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α), and microglial activation of the three groups were assessed.

Results

The behavioral scores of rats in the TS group and the TS + Hal group were higher than those in the CON group (P < 0.05), but the scores of behavioral tests in the TS + Hal group were lower than those in the TS group (P < 0.05). The levels of IL-6 and TNF-α in the rat brain tissue were significantly higher in the TS group than in the CON group (P < 0.05), while no significant differences were found between the CON group and the TS + Hal group (P > 0.05). The microglia was significantly activated in the TS group and slightly activated in the TS + Hal group, which was considerably less than that in the TS group.

Conclusion

The IDPN-induced TS rats had significant neuroinflammation in the brain, and the interaction between dopamine (DA) dysregulation and immune dysfunction may play a vital role in the pathogenic mechanisms of TS.

Have (R)-[11C]PK11195 challengers fulfilled the promise? A scoping review of clinical TSPO PET studies

PURPOSE

The prototypical TSPO radiotracer (R)-[11C]PK11195 has been used in humans for more than thirty years to visualize neuroinflammation in several pathologies. Alternative radiotracers have been developed to improve signal-to-noise ratio and started to be tested clinically in 2008. Here we examined the scientific value of these "(R)-[11C]PK11195 challengers" in clinical research to determine if they could supersede (R)-[11C]PK11195.

METHODS

A systematic MEDLINE (PubMed) search was performed (up to end of year 2020) to extract publications reporting TSPO PET in patients with identified pathologies, excluding studies in healthy subjects and methodological studies.

RESULTS

Of the 288 publications selected, 152 used 13 challengers, and 142 used (R)-[11C]PK11195. Over the last 20 years, the number of (R)-[11C]PK11195 studies remained stable (6 ± 3 per year), but was surpassed by the total number of challenger studies for the last 6 years. In total, 3914 patients underwent a TSPO PET scan, and 47% (1851 patients) received (R)-[11C]PK11195. The 2 main challengers were [11C]PBR28 (24%-938 patients) and [18F]FEPPA (11%-429 patients). Only one-in-ten patients (11%-447) underwent 2 TSPO scans, among whom 40 (1%) were scanned with 2 different TSPO radiotracers.

CONCLUSIONS

Generally, challengers confirmed disease-specific initial (R)-[11C]PK11195 findings. However, while their better signal-to-noise ratio seems particularly useful in diseases with moderate and widespread neuroinflammation, most challengers present an allelic-dependent (Ala147Thr polymorphism) TSPO binding and genetic stratification is hindering their clinical implementation. As new challengers, insensitive to TSPO human polymorphism, are about to enter clinical evaluation, we propose this systematic review to be regularly updated (living review).

Applicability, potential and limitations of TSPO PET imaging as a clinical immunopsychiatry biomarker

PURPOSE

TSPO PET imaging may hold promise as a single-step diagnostic work-up for clinical immunopsychiatry. This review paper on the clinical applicability of TSPO PET for primary psychiatric disorders discusses if and why TSPO PET imaging might become the first clinical immunopsychiatry biomarker and the investment prerequisites and scientific advancements needed to accommodate this transition from bench to bedside.

METHODS

We conducted a systematic search of the literature to identify clinical studies of TSPO PET imaging in patients with primary psychiatric disorders. We included both original case-control studies as well as longitudinal cohort studies of patients with a primary psychiatric diagnosis.

RESULTS

Thirty-one original studies met our inclusion criteria. In the field of immunopsychiatry, TSPO PET has until now mostly been studied in schizophrenia and related psychotic disorders, and to a lesser extent in mood disorders and neurodevelopmental disorders. Quantitative TSPO PET appears most promising as a predictive biomarker for the transdiagnostic identification of subgroups or disease stages that could benefit from immunological treatments, or as a prognostic biomarker forecasting patients' illness course. Current scanning protocols are still too unreliable, impractical and invasive for clinical use in symptomatic psychiatric patients.

CONCLUSION

TSPO PET imaging in its present form does not yet offer a sufficiently attractive cost-benefit ratio to become a clinical immunopsychiatry biomarker. Its translation to psychiatric clinical practice will depend on the prioritising of longitudinal research and the establishment of a uniform protocol rendering clinically meaningful TSPO uptake quantification at the shortest possible scan duration without arterial cannulation.

Depicting the composition of gut microbiota in children with tic disorders: an exploratory study

BACKGROUND

Symptom improvement in children with tic disorder (TD) following fecal microbiota transplantation led us to investigate the gut microbiota in TD. This exploratory study aims to depict the gut microbial profile in patients with TD and explore the impact of dopamine receptor antagonist (DRA) drugs on the composition and metabolic function of the gut microbiota.

METHODS

The gut microbiota were profiled in fecal samples of 49 children with TD and 50 matched healthy controls (HC) using shotgun metagenomic sequencing. A random forest (RF) model was constructed using the gut bacterial species to distinguish TD from HC. Associations between clinical metadata and microbial abundance or function were analyzed using MaAsLin2 and Spearman correlation.

RESULTS

The gut microbiota in children with TD was featured by higher abundances of Bacteroides plebeius and Ruminococcus lactaris (a potential pro-inflammatory taxon) and lower abundances of Prevotella stercorea and Streptococcus lutetiensis compared to HC. The constructed RF model accurately distinguished TD from HC based on the gut microbiota profile, resulting in an AUC of 0.884. Significant correlations were observed between tic symptom severity and the abundances of multiple bacterial species and gut microbiota metabolic functions. Multivariate analysis identified an upregulation of 4-aminobutanoate (GABA) degradation in the gut microbiota associated with TD status. The gut microbiota of DRA-treated TD children showed a distinct gut microbiota compared to the treatment-naïve group, represented by an increase in some potential enteric pathogens such as Escherichia coli, a decline in several species including Akkermansia muciniphila, and alterations in various metabolic functions.

CONCLUSIONS

Bacterial species promoting inflammatory responses and those modulating neurotransmitters such as GABA may be involved in the pathogenesis of TD. The use of DRA drugs is likely to induce overgrowth of some enteric pathogens and alter the gut microbiota metabolism.

Clinical Features in Patients With PANDAS/PANS and Therapeutic Approaches: A Retrospective Study

Objective: The clinical characteristics of patients with PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection) and PANS (pediatric acute-onset neuropsychiatric syndrome) and the efficacy of antibiotic therapy with psychotherapy and antipsychotics were investigated to improve neurological symptoms as well as obsessive compulsive disorder (OCD). Methods: We retrospectively analyzed 62 patients with a clinical diagnosis of PANDAS/PANS enrolled from May 14, 2013 to September 15, 2020 in the Neurology Childhood Division, Department of Pediatrics at Sapienza, Rome. Clinical manifestations, neurological and psychiatric, laboratory investigations, and familiar history were collected to evaluate the differences between the two groups. The effects of various therapeutic approaches were examined. Descriptive and comparative statistical analyses were performed. Results: The mean age at onset of PANDAS/PANS symptoms was 6.2 ± 1.2 years. The most common diagnosis was PANDAS, followed by PANS. Neurological and psychiatric symptoms were mostly evident in both groups (>70% of the population), with no significant difference between them (P = 0.52 and P = 0.15, respectively). Irritability, aggressivity, and food restriction were more prevalent in children with PANS than in those with PANDAS (P = 0.024 and P = 0.0023, respectively). The levels of anti-streptolysin O and anti-DNAse B 10-fold higher in PANDAS than those in PANS (P < 0.0001). Antibiotics or psychotherapy were administered in most cases (90.3 and 53.2%, respectively), followed by antipsychotic treatments (24.2%). In the multivariate analysis, among the therapies used, psychotherapy significantly resulted in the most efficacious relief of OCD, reducing stress in patients and their parents (P = 0.042). Conclusion: Our findings confirm a clear clinical difference between the two groups, PANDAS and PANS, using different approaches. In fact, irritability, aggressivity, and food restriction were significantly more frequent in children with PANS and the levels of anti-streptolysin O and anti-DNAse B were higher in PANDAS. Another relevant finding is the efficacy of psychotherapy, especially for obsessive-compulsive disorder, and of antibiotic prophylaxis in managing acute neurological symptoms.

Maternal immune activation and neuroinflammation in human neurodevelopmental disorders

Maternal health during pregnancy plays a major role in shaping health and disease risks in the offspring. The maternal immune activation hypothesis proposes that inflammatory perturbations in utero can affect fetal neurodevelopment, and evidence from human epidemiological studies supports an association between maternal inflammation during pregnancy and offspring neurodevelopmental disorders (NDDs). Diverse maternal inflammatory factors, including obesity, asthma, autoimmune disease, infection and psychosocial stress, are associated with an increased risk of NDDs in the offspring. In addition to inflammation, epigenetic factors are increasingly recognized to operate at the gene-environment interface during NDD pathogenesis. For example, integrated brain transcriptome and epigenetic analyses of individuals with NDDs demonstrate convergent dysregulated immune pathways. In this Review, we focus on the emerging human evidence for an association between maternal immune activation and childhood NDDs, including autism spectrum disorder, attention-deficit/hyperactivity disorder and Tourette syndrome. We refer to established pathophysiological concepts in animal models, including immune signalling across the placenta, epigenetic 'priming' of offspring microglia and postnatal immune-brain crosstalk. The increasing incidence of NDDs has created an urgent need to mitigate the risk and severity of these conditions through both preventive strategies in pregnancy and novel postnatal therapies targeting disease mechanisms.

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.

Metabolomic Characterization of Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS)

Introduction

PANS is a controversial clinical entity, consisting of a complex constellation of psychiatric symptoms, adventitious changes, and expression of various serological alterations, likely sustained by an autoimmune/inflammatory disease. Detection of novel biomarkers of PANS is highly desirable for both diagnostic and therapeutic management of affected patients. Analysis of metabolites has proven useful in detecting biomarkers for other neuroimmune-psychiatric diseases. Here, we utilize the metabolomics approach to determine whether it is possible to define a specific metabolic pattern in patients affected by PANS compared to healthy subjects.

Design

This observational case-control study tested consecutive patients referred for PANS between June 2019 to May 2020. A PANS diagnosis was confirmed according to the PANS working criteria (National Institute of Mental Health [NIMH], 2010). Healthy age and sex-matched subjects were recruited as controls.

Methods

Thirty-four outpatients referred for PANS (mean age 9.5 years; SD 2.9, 71% male) and 25 neurotypical subjects matched for age and gender, were subjected to metabolite analysis. Serum samples were obtained from each participant and were analyzed using Nuclear Magnetic Resonance (NMR) spectroscopy. Subsequently, multivariate and univariate statistical analyses and Receiver Operator Curves (ROC) were performed.

Results

Separation of the samples, in line with the presence of PANS diagnosis, was observed by applying a supervised model (R²X = 0.44, R²Y = 0.54, Q² = 0.44, p-value < 0.0001). The significantly altered variables were 2-Hydroxybutyrate, glycine, glutamine, histidine, tryptophan. Pathway analysis indicated that phenylalanine, tyrosine, and tryptophan metabolism, as well as glutamine and glutamate metabolism, exhibited the largest deviations from neurotypical controls.

Conclusion

We found a unique plasma metabolic profile in PANS patients, significantly differing from that of healthy children, that suggests the involvement of specific patterns of neurotransmission (tryptophan, glycine, histamine/histidine) as well as a more general state of neuroinflammation and oxidative stress (glutamine, 2-Hydroxybutyrate, and tryptophan-kynurenine pathway) in the disorder. This metabolomics study offers new insights into biological mechanisms underpinning the disorder and supports research of other potential biomarkers implicated in PANS.

Hypoferritinemia and iron deficiency in youth with pediatric acute-onset neuropsychiatric syndrome

BACKGROUND

Pediatric acute-onset neuropsychiatric syndrome (PANS) is an abrupt debilitating psychiatric illness. We anecdotally observed hypoferritinemia and iron deficiency in a subset of patients with PANS, prompting this study.

METHODS

In this IRB-approved prospective cohort study, we included patients seen at the Stanford PANS Clinic who met study criteria. The prevalence of hypoferritinemia (using cut-offs of 7 ng/ml in children ≤ 15 years and 18 ng/ml in adolescents > 15 years) and iron deficiency was estimated. Differences in patients with and without hypoferritinemia during PANS flare were explored.

RESULTS

Seventy-nine subjects (mean age of PANS onset of 8.7 years) met study criteria. Hypoferritinemia was observed in 27% and three quarters occurred during a PANS flare. Compared to patients without hypoferritinemia during PANS flare, patients with hypoferritinemia had worse global impairment, more comorbid inflammatory diseases, and exhibited a chronic course of PANS illness. The estimated prevalence of iron deficiency was 3-8% in the PANS cohort, 1.4-2.0-fold higher than in the age- and sex-matched U.S.

POPULATION

More stringent ferritin level cut-offs than the comparison CDC dataset were used.

CONCLUSION

Hypoferritinemia and iron deficiency appear to be more common in PANS patients. More research is needed to confirm and understand this association.

IMPACT

Our study suggests hypoferritinemia and iron deficiency are more common in patients with pediatric acute-onset neuropsychiatric syndrome (PANS) than in the sex- and age-matched US population. Hypoferritinemia was commonly observed during a disease flare but not associated with dietary or demographic factors. In patients with PANS and iron deficiency, clinicians should consider possibility of inflammation as the cause especially if iron deficiency cannot be explained by diet and blood loss. Future research should include larger cohorts to corroborate our study findings and consider examining the iron dynamics on MRI brain imaging in order to better understand the pathophysiology of PANS.

Patients with abrupt early-onset OCD due to PANS tolerate lower doses of antidepressants and antipsychotics

OBJECTIVE

To characterize drug tolerability in pediatric patients with an abrupt-onset of obsessive-compulsive disorder (OCD) meeting criteria for pediatric acute-onset neuropsychiatric syndrome (PANS).

METHODS

We reviewed charts of 188 consecutive patients with PANS seen in the PANS clinic, collecting starting, side effect, and tolerated doses, as well as side effect profile for each antidepressant and antipsychotic trial.

RESULTS

Of 188 included patients: 57% had trials of antidepressants and/or antipsychotics. Patients prescribed psychotropics were older at PANS onset (mean 9.5 vs 7.1 years, p < 0.01) and had had a longer delay before presenting to clinic (median 1.4 vs 0.5 years, p < 0.01). Antidepressant indications (n = 146) were OCD (48%), anxiety (44%), and depression (32%). Antipsychotic indications (n = 119) were aggression (34%), psychotic symptoms (28%), and OCD (24%). Side effects requiring medication change occurred in 54% of patients: in 38% of antidepressant trials and 49% of antipsychotic trials. Antidepressants' most common side effects were anxiety, agitation, aggression, and akathisia. Antipsychotics' most common side effects were dystonia, aggression, self-injurious behavior, and movement abnormality. Side effects were common at doses lower than the suggested starting doses for these medications. Patients tolerated antidepressants and antipsychotics when doses were low.

CONCLUSION

When antidepressants and antipsychotics are prescribed to patients with PANS, intolerable side effects were noted at doses lower than or equal to suggested starting doses. Patients with PANS can benefit from these therapies. However, when treating these patients, clinicians are advised to start with significantly lower doses than they might use in other disorders.

Immunological Dysfunction in Tourette Syndrome and Related Disorders

Chronic tic disorder and Tourette syndrome are common childhood-onset neurological diseases. However, the pathophysiology underlying these disorders is unclear, and most studies have focused on the disinhibition of the corticostriatal–thalamocortical circuit. An autoimmune dysfunction has been proposed in the pathogenetic mechanism of Tourette syndrome and related neuropsychiatric disorders such as obsessive–compulsive disorder, autism, and attention-deficit/hyperactivity disorder. This is based on evidence from animal model studies and clinical findings. Herein, we review and give an update on the clinical characteristics, clinical evidence, and genetic studies in vitro as well as animal studies regarding immune dysfunction in Tourette syndrome.

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.

An examination of the relationship between regulatory T cells and symptom flare-ups in children and adolescents diagnosed with chronic tic disorder and Tourette syndrome

BACKGROUND

Tourette syndrome (TS) is a childhood-onset neurodevelopmental disorder characterized by several motor and phonic tics.

AIMS

In this study, we aimed to compare activated regulatory T cell (Treg) values between patients with TS/chronic tic disorder (CTD) and age- and sex-matched healthy controls (HCs).

MATERIALS AND METHOD

Patients with TS/CTD and age- and sex-matched HCs were included in the study. The severity of the disease was evaluated using the Yale Global Tic Severity Scale. CD4⁺CD25⁺CD127^low Tregs from the patient group and the control group were compared using flow cytometry.

RESULTS

The study included 48 patients diagnosed with TS/CTD (36 males and 12 females, mean age: 11.58 ± 2.61) and 24 HCs (18 males and 6 females, mean age: 11.63 ± 2.60). The TS/CTD group had significantly higher activated regulatory T percentile with respect to the T helper value compared to the HCs (p = 0.010). Lymphocyte count, T lymphocyte count, T lymphocyte percentage, T-helper lymphocyte count, and T-helper lymphocyte percentage were lower in the patient group compared to the control group (p = 0.024, 0.003, 0.007, <0.001, <0.001, respectively). The comparison of three groups (mild, moderate-severe, and HCs) revealed that T lymphocyte number and percentage and the T helper number and percentage were significantly higher in the HC group compared to the moderate-severe group, whereas the activated Treg percentage with respect to the T helper value was significantly higher in the moderate-severe group compared to the HC group (0.002, 0.026, <0.001, <0.001, 0.027, respectively).

CONCLUSION

Our results suggest that Tregs may have a role in the pathogenesis of TS/CTD.

Discovering prescription patterns in pediatric acute-onset neuropsychiatric syndrome patients

OBJECTIVE

Pediatric acute-onset neuropsychiatric syndrome (PANS) is a complex neuropsychiatric syndrome characterized by an abrupt onset of obsessive-compulsive symptoms and/or severe eating restrictions, along with at least two concomitant debilitating cognitive, behavioral, or neurological symptoms. A wide range of pharmacological interventions along with behavioral and environmental modifications, and psychotherapies have been adopted to treat symptoms and underlying etiologies. Our goal was to develop a data-driven approach to identify treatment patterns in this cohort.

MATERIALS AND METHODS

In this cohort study, we extracted medical prescription histories from electronic health records. We developed a modified dynamic programming approach to perform global alignment of those medication histories. Our approach is unique since it considers time gaps in prescription patterns as part of the similarity strategy.

RESULTS

This study included 43 consecutive new-onset pre-pubertal patients who had at least 3 clinic visits. Our algorithm identified six clusters with distinct medication usage history which may represent clinician's practice of treating PANS of different severities and etiologies i.e., two most severe groups requiring high dose intravenous steroids; two arthritic or inflammatory groups requiring prolonged nonsteroidal anti-inflammatory drug (NSAID); and two mild relapsing/remitting group treated with a short course of NSAID. The psychometric scores as outcomes in each cluster generally improved within the first two years.

DISCUSSION AND CONCLUSION

Our algorithm shows potential to improve our knowledge of treatment patterns in the PANS cohort, while helping clinicians understand how patients respond to a combination of drugs.

PANS/PANDAS: Clinical Experience in IVIG Treatment and State of the Art in Rehabilitation Approaches

Pediatric acute-onset neuropsychiatric syndrome (PANS) is a condition characterized by the abrupt, dramatic onset of obsessive–compulsive disorder (OCD) or eating restriction accompanied by equally abrupt and severe comorbid neuropsychiatric symptoms. PANDAS (pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection) is a heterogeneous syndrome identified as post-Streptococcus pyogenes infection (β-hemolytic Streptococcus group A) complications regarding the central nervous system with specific involvement of neuropsychiatric and behavioral skills. In the first part of our study, we share our experience in the treatment of a group of extreme-grade (according to CY-BOCS severity scale) symptomatic patients with intravenous immunoglobulin (IVIG), following the most recent studies regarding the dosage of the drug. Our contribution is to share our experience made on a sample of 55 patients all in the highest level of a severity grade. In the second part of our study, we also analyze the literature on PANS/PANDAS rehabilitation therapy, since in the literature there is no discussion of union and comparison on this method. Objective: This study aims to evaluate the clinical features of the patients observed from different Italian cohorts, with the attempt at evaluating clinical response to IVIG treatment in children with an extreme severity grade of PANS/PANDAS disease. Furthermore, after having analyzed the literature, we propose rehabilitation therapy as an added value to the pharmacological treatment. Materials and Methods: A total of 55 patients with a diagnosis of PANS/PANDAS, who belonged to an extreme grade of disease, were enrolled. All patients were administered with IVIG treatment at 2 g/kg per day for two consecutive days. Results: From our study, a noticeable improvement (until complete remission) of symptoms was evident for at least one year in 47 out of 55 (85%) observed children, while 11 out of these 43 (25%) showed an evident symptoms remission in a single attempt and the remaining 32 (75%) required a second administration to notice a lasting symptomatic improvement.

Sydenham's Chorea; Clinical and Magnetic Resonance Imaging Findings, a Retrospective Observational Study in Children

The purpose of this study was to evaluate the correlation between magnetic resonance imaging (MRI) findings and demographic and clinical characteristics, response to treatment times, and recurrence rates of Sydenham's chorea (SC), the most common of the acquired pediatric choreas. The clinical and radiological findings of 12 patients presenting to the pediatric neurology clinic in the previous 4 years and diagnosed with SC on the basis of the modified Jones criteria were investigated retrospectively from the hospital files. In addition, we measured the maximum prefrontal cortex and basal ganglia (globus pallidus, putamen, and caudate nucleus) thicknesses in the axial plane from patients' cerebral MRIs and compared these values with prefrontal cortex and basal ganglia thicknesses of a healthy control group measured using the same technique. Patient and control groups' cranial and basal ganglia MRIs were found to be normal. However, patients' globus pallidus thicknesses were significantly lower than those of the healthy control group. Additionally, the globus pallidus values of patients with recurrent SC and a prolonged healing time were lower than average. However, we determined no significant difference in terms of prefrontal motor cortex, caudate nucleus, or putamen thicknesses between the patient and control groups. Low globus pallidus thicknesses in patients with SC may indicate atrophy associated with globus pallidus involvement. Further experimental and prospective and long-term studies are needed for a better understanding of the factors affecting the pathophysiology, recurrence, and healing time of SC.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

Regulatory effects of Ningdong granule on microglia-mediated neuroinflammation in a rat model of Tourette's syndrome

Tourette's syndrome (TS) is an inherited neurologic disorder characterized by involuntary stereotyped motor and vocal tics. Its pathogenesis is still unclear and its treatment remains limited. Recent research has suggested the involvement of immune mechanisms in the pathophysiology of TS. Microglia are the brain's resident innate immune cells. They can mediate neuroinflammation and regulate brain development and homeostasis. A traditional Chinese medicine (TCM), Ningdong granule (NDG), has been found to be efficacious in the treatment of TS while causing few adverse reactions. In the current study, a rat model of 3,3'-iminodipropionitrile (IDPN)-induced TS was used to explore the regulating effects and mechanisms of NDG on microglia-mediated neuroinflammation. IDNP led to robust pathological changes and neurobehavioral complications, with activation of microglia in the striatum of rats with TS. After activation by IDNP, microglia strongly responded to this specific injury, and TNF-α, IL-6, and MCP-1 were released in the striatum and/or serum of rats with TS. Interestingly, NDG inhibited the activation of microglia and decreased the abnormal expression of TNF-α, IL-6, and MCP-1 in the striatum and/or serum of rats with TS, thus controlling tics. However, there were no significant changes in the striatum and/or serum of rats with TS after treatment with haloperidol. The anti-TS action of haloperidol might occur not through microglial activation and neuroinflammation but through the DAT system, thus controlling tics. In conclusion, microglia might play key roles in mediating neuroinflammatory responses in TS, triggering the release of TNF-α, IL-6, and MCP-1.NDG inhibited tics in rats with TS, and this mechanism may be associated with a reduction in the increased number of activated microglia and a decrease in the expression of pro-inflammatory cytokines and chemokines in the striatum and/or serum.

Autoantibody Biomarkers for Basal Ganglia Encephalitis in Sydenham Chorea and Pediatric Autoimmune Neuropsychiatric Disorder Associated With Streptococcal Infections

Movement, behavioral, and neuropsychiatric disorders in children have been linked to infections and a group of anti-neuronal autoantibodies, implying dopamine receptor-mediated encephalitis within the basal ganglia. The purpose of this study was to determine if anti-neuronal biomarkers, when used as a group, confirmed the acute disease in Sydenham chorea (SC) and pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS). IgG autoantibodies against four neuronal autoantigens (tubulin, lysoganglioside GM1, and dopamine receptors D1 and D2) were detected in SC sera (N=8), sera and/or cerebrospinal fluid (CSF) from two groups of PANDAS cases (N=25 first group and N=35 second group), sera from Tourette's syndrome (N=18), obsessive-compulsive disorder (N=25), attention deficit hyperactivity disorder (N=18), and healthy controls (N=28) by direct enzyme-linked immunosorbent assay (ELISA). IgG specific for neuronal autoantigens was significantly elevated during the acute symptomatic phase, and the activity of calcium/calmodulin-dependent protein kinase II (CaMKII) pathway was significantly elevated in human neuronal cells. Five assays confirmed the disease in SC and in two groups of children with PANDAS. In 35 acute onset PANDAS patients, 32 sera (91.4%) were positive for one or more of the anti-neuronal autoantibodies compared with 9 of 28 healthy controls (32.1%, p<0.0001). Importantly, CSF of 32 (91.4%) PANDAS patients had one or more detectable anti-neuronal autoantibody titers and CaMKII activation. Among healthy control subjects with elevated serum autoantibody titers for individual antigens, none (0%) were positively associated with elevated positive CaMKII activation, which was a striking contrast to the sera of PANDAS subjects, who had 76-89% positive association with elevated individual autoantibody titers and positive CaMKII activity. At 6 months follow-up, symptoms improved for more than 80% of PANDAS subjects, and serum autoantibody titers also significantly decreased. Results reported herein and previously published studies in our laboratory suggest the antibody biomarkers may be a useful adjunct to clinical diagnosis of SC, PANDAS, and related disorders and are the first known group of autoantibodies detecting dopamine receptor-mediated encephalitis in children.

Neuropsychiatric consequences of childhood group A streptococcal infection: A systematic review of preclinical models

In recent years, clinical studies have shown strong epidemiological evidence of an increased risk of developing neuropsychiatric disorders after childhood exposure to streptococcal infection, including the Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infection (PANDAS). New preclinical studies on group A streptococcus (GAS) exposure investigate how to disentangle the influences of immune activation to induce long-term neurobehavioral effects associated with neuropsychiatric disorders such as obsessive-compulsive disorder, schizophrenia or autism. The present systematic review collects neurobehavioral evidence regarding the use of GAS exposure in animal models to study the vulnerability to different neuropsychiatric disorders, improving our understanding of its possible causes and consequences, and compares its contribution with other preclinical models of immune activation in a variety of paradigms. Specifically, we reviewed the effects of postnatal GAS exposure, in comparison with post- and prenatal exposure to Lipopolysaccharide (LPS) and Polyinosinic:polycytidylic acid (Poly I:C), on the long-term effects concerning psychomotor, cognition and socioemotional outcomes in rodents. GAS exposure in animal models has revealed different behavioral alterations such as reduced locomotion and motor coordination, a deficit in sensorimotor gating, learning, working memory, altered social behavior, and increased anxiety and stereotyped behavior. Most of the results found are in accordance with other immune activation models -LPS and Poly I:C-, with some discrepancies. The systematic review of the literature supports the preclinical model of GAS exposure as a valid model for studying the neurobehavioral consequences of streptococcal infections. Future studies on streptococcal infection could contribute increasing our knowledge on preventive actions or treatments for neuropsychiatric disorders.

Association of Pediatric Acute-Onset Neuropsychiatric Syndrome With Microstructural Differences in Brain Regions Detected via Diffusion-Weighted Magnetic Resonance Imaging

IMPORTANCE

Epidemiological studies indicate a link between obsessive-compulsive disorder and infections, particularly streptococcal pharyngitis. Pediatric acute-onset neuropsychiatric syndrome (PANS) manifests suddenly with obsessions, compulsions, and other behavioral disturbances, often after an infectious trigger. The current working model suggests a unifying inflammatory process involving the central nervous system, particularly the basal ganglia.

OBJECTIVE

To investigate whether diffusion-weighted magnetic resonance imaging (DWI) detects microstructural abnormalities across the brain regions of children with PANS.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study performed at a single-center, multidisciplinary clinic in the United States focusing on the evaluation and treatment of children with PANS. Sixty consecutive patients who underwent 3 Tesla (T) magnetic resonance imaging (MRI) before immunomodulation from September 3, 2012, to March 30, 2018, were retrospectively reviewed for study inclusion. Six patients were excluded by blinded investigators because of imaging or motion artifacts, 3 patients for major pathologies, and 17 patients for suboptimal atlas image registration. In total, 34 patients with PANS before initiation of treatment were compared with 64 pediatric control participants.

MAIN OUTCOMES AND MEASURES

Using atlas-based MRI analysis, regional brain volume, diffusion, and cerebral blood flow were measured in the cerebral white matter, cerebral cortex, thalamus, caudate, putamen, pallidum, hippocampus, amygdala, nucleus accumbens, and brainstem. An age and sex-controlled multivariable analysis of covariance was used to compare patients with control participants.

RESULTS

This study compared 34 patients with PANS (median age, 154 months; age range, 55-251 months; 17 girls and 17 boys) and 64 pediatric control participants (median age, 139 months; age range, 48-213 months); 41 girls and 23 boys). Multivariable analysis demonstrated a statistically significant difference in MRI parameters between patients with PANS and control participants (F21,74 = 6.91; P < .001; partial η2 = 0.662). All assessed brain regions had statistically significantly increased median diffusivity compared with 64 control participants. Specifically, the deep gray matter (eg, the thalamus, basal ganglia, and amygdala) demonstrated the most profound increases in diffusivity consistent with the cardinal clinical symptoms of obsessions, compulsions, emotional dysregulation, and sleep disturbances. No statistically significant differences were found regarding volume and cerebral blood flow.

CONCLUSIONS AND RELEVANCE

This study identifies cerebral microstructural differences in children with PANS in multiple brain structures, including the deep gray matter structures (eg, the thalamus, basal ganglia, and amygdala). Further study of MRI is warranted in prospective, clinical trials as a potential quantitative method for assessing patients under evaluation for PANS.