Immune aberrations in children with Autism Spectrum Disorder: a case-control study from a tertiary care neuropsychiatric hospital in India

Causal effects of 731 immune cell phenotypes on autism spectrum disorder: a Mendelian randomization study

Objective

The role of different immune cells in autism spectrum disorders (ASD) is still controversial. The purpose of this study was to evaluate the causal effects of different immune cell phenotypes on ASD via Mendelian randomization (MR).

Methods

Datasets of immune cell phenotypes were obtained from the European Bioinformatics Institute, and datasets of ASD were obtained from the IEU Open GWAS project. Single nucleotide polymorphisms were selected based on the assumptions of association, independence, and exclusivity. Inverse variance weighted was utilized as the main method for MR analysis. MR-Egger was employed to assess the horizontal pleiotropy of the results. Cochran's Q and leave-one-out method were used for heterogeneity analysis and sensitivity analysis of the results, respectively.

Results

MR analysis showed that TD CD8br AC [odds ratio (OR), 1.137; 95% confidence interval (CI), 1.031-1.254; p = 0.010], CD8br %leukocyte (OR, 1.142; 95% CI, 1.067-1.223; p < 0.001), CD8br and CD8dim %leukocyte (OR, 1.117; 95% CI, 1.032-1.210; p = 0.006), naive CD8br %T cell (OR, 1.052; 95% CI, 1.004-1.104; p = 0.035), CD28- CD8dim %T cell (OR, 1.097; 95% CI, 1.038-1.158; p < 0.001), CD127- CD8br AC (OR, 1.086; 95% CI, 1.006-1.171; p = 0.034), CD45 on CD8br (OR, 1.059; 95% CI, 1.021-1.099; p = 0.002), CD3 on HLA DR+ CD8br (OR, 1.098; 95% CI, 1.041-1.158; p < 0.001), CD4 on activated Treg (OR, 1.048; 95% CI, 1.001-1.096; p = 0.046), CD3 on CD39+ resting Treg (OR, 1.070; 95% CI, 1.012-1.131; p = 0.018), IgD+ CD38- %lymphocyte (OR, 1.103; 95% CI, 1.023-1.190; p = 0.011), CD62L- plasmacytoid DC %DC (OR, 1.046; 95% CI, 1.001-1.093; p = 0.046), and FSC-A on plasmacytoid DC (OR, 1.075; 95% CI, 1.003-1.153; p = 0.042) were associated with increased genetic susceptibility to ASD. MR-Egger displayed no horizontal pleiotropy (p ≥ 0.05). Cochran's Q revealed no heterogeneity of results (p ≥ 0.05). Sensitivity analysis indicated that the results were robust.

Conclusion

This MR analysis revealed 13 immune cell phenotypes associated with increased genetic susceptibility to ASD and emphasized the importance of CD8 T cells and Tregs, which provides new directions for the pathogenesis and drug research of ASD.

Comprehensive immunoprofiling of neurodevelopmental disorders suggests three distinct classes based on increased neurogenesis, Th-1 polarization or IL-1 signaling

Neurodevelopmental disorders (NDDs) are a spectrum of conditions with commonalities as well as differences in terms of phenome, symptomatome, neuropathology, risk factors and underlying mechanisms. Immune dysregulation has surfaced as a major pathway in NDDs. However, it is not known if neurodevelopmental disorders share a common immunopathogenetic mechanism. In this study, we explored the possibility of a shared immune etiology in three early-onset NDDs, namely Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD) and Intellectual Disability Disorder (IDD). A panel of 48 immune pathway-related markers was assayed in 135 children with NDDs, represented by 45 children with ASD, ADHD and IDD in each group, along with 35 typically developing children. The plasma levels of 48 immune markers were analyzed on the Multiplex Suspension Assay platform using Pro Human cytokine 48-plex kits. Based on the cytokine/chemokine/growth factor levels, different immune profiles were computed. The primary characteristics of NDDs are depletion of the compensatory immune-regulatory system (CIRS) (z composite of IL-4, IL-10, sIL-1RA, and sIL-2R), increased interleukin (IL)-1 signaling associated with elevated IL-1α and decreased IL-1-receptor antagonist levels, increased neurogenesis, M1/M2 macrophage polarization and increased IL-4 as well as C-C Motif Chemokine Ligand 2 (CCL2) levels. With a cross-validated sensitivity of 81.8% and specificity of 94.4%, these aberrations seem specific for NDDs. Many immunological abnormalities are shared by ASD, ADHD and IDD, which are distinguished by minor differences in IL-9, IL-17 and CCL12. In contrast, machine learning reveals that NDD group consists of three immunologically distinct clusters, with enhanced neurogenesis, Th-1 polarization, or IL-1 signaling as the defining features. NDD is characterized by immune abnormalities that have functional implications for neurogenesis, neurotoxicity, and neurodevelopment. Using machine learning, NDD patients could be classified into subgroups with qualitatively distinct immune disorders that may serve as novel drug targets for the treatment of NDDs.

Disease Course and Response to Immunotherapy in Children With Childhood Disintegrative Disorder: A Retrospective Case Series

Childhood disintegrative disorder is a poorly understood neurobehavioral disorder of early childhood characterized by acute to subacute profound regression in previously developed language, social behavior, and adaptive functions. The etiology of childhood disintegrative disorder remains unknown and treatment is focused on symptomatic management. Interest in neuroinflammatory mechanisms has grown with the increased recognition of autoimmune brain diseases and similarities between the presenting symptoms of childhood disintegrative disorder and pediatric autoimmune encephalitis. Importantly, a diagnosis of pediatric autoimmune encephalitis requires evidence of inflammation on paraclinical testing, which is absent in childhood disintegrative disorder. Here we report 5 children with childhood disintegrative disorder who were initially diagnosed with possible autoimmune encephalitis and treated with immunotherapy. Two children had provocative improvements, whereas 3 did not change significantly on immunotherapy. Additionally, a sixth patient with childhood disintegrative disorder evaluated in our Autoimmune Brain Disease Clinic showed spontaneous improvement and is included to highlight the variable natural history of childhood disintegrative disorder that may mimic treatment responsiveness.

Association between NKG2/KLR gene variants and epilepsy in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a set of neurodevelopmental disorders mainly characterized by repetitive, restrictive and stereotypical behaviors, and impaired communication skills. Several lines of evidence indicate that alterations of the immune system account for ASD development, including the presence of brain-reactive antibodies, abnormal T cell activation, altered cytokine levels in brain, cerebrospinal fluid and peripheral blood circulation, increased levels of circulating monocytes, and dysregulation in Natural Killer (NK) cells activity. Regarding NK cells, a lower cytotoxic activity, a higher level of activation and an increased number of these cells in individuals with ASD have been described. In 2019, a study showed that NK cells derived from patients with ASD show a characteristic pattern of NKG2C overexpression, highlighting the importance of the NK cell pathway in ASD. In fact, the study of genes related to NK cell activity has proven to be an excellent research target, both in terms of susceptibility as well as a marker for the different clinical manifestations observed in ASD individuals. Here, we evaluated the influence of KLRC2 gene deletion as well as KLRK1 rs1049174 and rs2255336 variants in a cohort of 185 children diagnosed with ASD and their respective biological parents in southern Brazil. Of note, this is the first study concerning genetic variants of the KLRC2 and KLRK1 genes in an ASD sample. The KLRC2 gene deletion (p = 0.001; pc = 0.009), KLRK1 rs1049174 (p = 0.005; pc = 0.045) and KLRK1 rs2255336 (p = 0.001; pc = 0.009) were associated with epilepsy in ASD patients. The results indicate that KLRC2 deletion, KLRK1 rs2255336, and KLRK1 rs1049174 could be involved in epilepsy manifestation in ASD patients, possibly impacting the NK dysregulation already described in ASD and epileptic patients.

Integrative analysis of γδT cells and dietary factors reveals predictive values for autism spectrum disorder in children

BACKGROUND

Autism spectrum disorder (ASD) includes a range of multifactorial neurodevelopmental disabilities characterized by a variable set of neuropsychiatric symptoms. Immunological abnormalities have been considered to play important roles in the pathogenesis of ASD, but it is still unknown which abnormalities are more prominent.

METHODS

A total of 105 children with ASD and 105 age and gender-matched typically developing (TD) children were recruited. An eating and mealtime behavior questionnaire, dietary habits, and the Bristol Stool Scale were investigated. The immune cell profiles in peripheral blood were analyzed by flow cytometry, and cytokines (IFN-γ, IL-8, IL-10, IL-17A, and TNF-α) in plasma were examined by Luminex assay. The obtained results were further validated using an external validation cohort including 82 children with ASD and 51 TD children.

RESULTS

Compared to TD children, children with ASD had significant eating and mealtime behavioral changes and gastrointestinal symptoms characterized by increased food fussiness and emotional eating, decreased fruit and vegetable consumption, and increased stool astriction. The proportion of γδT cells was significantly higher in children with ASD than TD children (β: 0.156; 95% CI: 0.888 ∼ 2.135, p < 0.001) even after adjusting for gender, eating and mealtime behaviors, and dietary habits. In addition, the increased γδT cells were evident in all age groups (age < 48 months: β: 0.288; 95% CI: 0.420 ∼ 4.899, p = 0.020; age ≥ 48 months: β: 0.458; 95% CI: 0.694 ∼ 9.352, p = 0.024), as well as in boys (β: 0.174; 95% CI: 0.834 ∼ 2.625, p < 0.001) but not in girls. These findings were also confirmed by an external validation cohort. Furthermore, IL-17, but not IFN-γ, secretion by the circulating γδT cells was increased in ASD children. Machine learning revealed that the area under the curve in nomogram plots for increased γδT cells combined with eating behavior/dietary factors was 0.905, which held true in both boys and girls and in all the age groups of ASD children. The decision curves showed that children can receive significantly higher diagnostic benefit within the threshold probability range from 0 to 1.0 in the nomogram model.

CONCLUSIONS

Children with ASD present with divergent eating and mealtime behaviors and dietary habits as well as gastrointestinal symptoms. In peripheral blood, γδT cells but not αβT cells are associated with ASD. The increased γδT cells combined with eating and mealtime behavior/dietary factors have a high value for assisting in the diagnosis of ASD.

Analysis of potential biomarkers and immune infiltration in autism based on bioinformatics analysis

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder caused by both environmental and genetic factors. However, its etiology and pathogenesis remain unclear. The purpose of this study was to establish an immune-related diagnostic model for ASD using bioinformatics methods and to identify ASD biomarkers. Two ASD datasets, GSE18123 and GSE29691, were integrated into the gene expression Database to eliminate batch effects. 41 differentially expressed genes were identified by microarray data linear model (limma package). Based on the results of the immune infiltration analysis, we speculated that neutrophils, B cells naive, CD8+ T cells, and Tregs are potential core immune cells in ASD and participate in the occurrence of ASD. Finally, the differential genes and immune infiltration in ASD and non-ASD patients were compared, and the most relevant genes were selected to construct the first immune correlation prediction model of ASD. After the calculation, the model exhibited better accuracy. The calculations show that the model has good accuracy.

Assessment of a multisite standardized biospecimen collection protocol for immune phenotyping in neurodevelopmental disorders

Multisite collection and preservation of peripheral blood mononuclear cells (PBMCs) for centralized analysis is an indispensable strategy for large cohort immune phenotyping studies. However, the absence of cross-site standardized protocols introduces unnecessary sample variance. Here we describe the protocol implemented by the Province of Ontario Neurodevelopmental Disorders (POND) Network's immune platform for the multisite collection, processing, and cryopreservation of PBMCs. We outline quality control standards and evaluate the performance of our PBMC processing and storage protocol. We also describe the Child Immune History Questionnaire results, an assessment tool evaluating pre-existing immune conditions in children with neurodevelopmental disorders (NDDs). Cell viability was assessed in samples from 178 participants based on strict quality control criteria. Overall, 83.1% of samples passed quality control standards. Samples collected and processed at the same site had higher quality control pass rates than samples that were collected and subsequently shipped to another site for processing. We investigated if freezer time impacted sample viability and found no difference in mean freezer time between samples that passed and failed quality control. The Child Immune History Questionnaire had a response rate of 87.1%. The described protocol produces viable samples that may be used in future immune phenotyping experiments.

Sex Differences in Neurodevelopmental Disorders: A Key Role for the Immune System

Sex differences are prominent defining features of neurodevelopmental disorders. Understanding the sex biases in these disorders can shed light on mechanisms leading to relative risk and resilience for the disorders, as well as more broadly advance our understanding of how sex differences may relate to brain development. The prevalence of neurodevelopmental disorders is increasing, and the two most common neurodevelopmental disorders, Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) exhibit male-biases in prevalence rates and sex differences in symptomology. While the causes of neurodevelopmental disorders and their sex differences remain to be fully understood, increasing evidence suggests that the immune system plays a critical role in shaping development. In this chapter we discuss sex differences in prevalence and symptomology of ASD and ADHD, review sexual differentiation and immune regulation of neurodevelopment, and discuss findings from human and rodent studies of immune dysregulation and perinatal immune perturbation as they relate to potential mechanisms underlying neurodevelopmental disorders. This chapter will give an overview of how understanding sex differences in neuroimmune function in the context of neurodevelopmental disorders could lend insight into their etiologies and better treatment strategies.

Combination of machine learning-based bulk and single-cell genomics reveals necroptosis-related molecular subtypes and immunological features in autism spectrum disorder

Background

Necroptosis is a novel form of controlled cell death that contributes to the progression of various illnesses. Nonetheless, the function and significance of necroptosis in autism spectrum disorders (ASD) remain unknown and require further investigation.

Methods

We utilized single-nucleus RNA sequencing (snRNA-seq) data to assess the expression patterns of necroptosis in children with autism spectrum disorder (ASD) based on 159 necroptosis-related genes. We identified differentially expressed NRGs and used an unsupervised clustering approach to divide ASD children into distinct molecular subgroups. We also evaluated immunological infiltrations and immune checkpoints using the CIBERSORT algorithm. Characteristic NRGs, identified by the LASSO, RF, and SVM-RFE algorithms, were utilized to construct a risk model. Moreover, functional enrichment, immune infiltration, and CMap analysis were further explored. Additionally, external validation was performed using RT-PCR analysis.

Results

Both snRNA-seq and bulk transcriptome data demonstrated a greater necroptosis score in ASD children. Among these cell subtypes, excitatory neurons, inhibitory neurons, and endothelials displayed the highest activity of necroptosis. Children with ASD were categorized into two subtypes of necroptosis, and subtype2 exhibited higher immune activity. Four characteristic NRGs (TICAM1, CASP1, CAPN1, and CHMP4A) identified using three machine learning algorithms could predict the onset of ASD. Nomograms, calibration curves, and decision curve analysis (DCA) based on 3-NRG have been shown to have clinical benefit in children with ASD. Furthermore, necroptosis-based riskScore was found to be positively associated with immune activation. Finally, RT-PCR demonstrated differentially expressed of these four NRGs in human peripheral blood samples.

Conclusion

A comprehensive identification of necroptosis may shed light on the underlying pathogenic process driving ASD onset. The classification of necroptosis subtypes and construction of a necroptosis-related risk model may yield significant insights for the individualized treatment of children with ASD.

In search of immune cellular sources of abnormal cytokines in the blood in autism spectrum disorder: A systematic review of case-control studies

Abnormal cytokine levels in circulating blood have been repeatedly reported in autism; however, the underlying cause remains unclear. This systematic review aimed to investigate cytokine levels in peripheral blood compartments and identify their potential immune cellular sources in subjects with autism through comparison with controls. We conducted an electronic database search (PubMed, Scopus, ProQuest Central, Ovid, SAGE Journals, and Wiley Online Library) from inception (no time limits) to July 9, 2020, and identified 75 relevant articles. Our qualitative data synthesis focused on results consistently described in at least three independent studies, and we reported the results according to the PRISMA protocol. We found that compared with controls, in subjects with autism, cytokines IL-6, IL-17, TNF-α, and IL-1β increased in the plasma and serum. We also identified monocytes, neutrophils, and CD4+ T cells as potential sources of these elevated cytokines in autism. Cytokines IFN-γ, TGF-β, RANTES, and IL-8 were increased in the plasma/serum of subjects with autism, and IFN-γ was likely produced by CD4+ T cells and natural killer (NK) cells, although conflicting evidence is present for IFN-γ and TGF-β. Other cytokines—IL-13, IL-10, IL-5, and IL-4—were found to be unaltered in the plasma/serum and post-stimulated blood immune cells in autistic individuals as compared with controls. The frequencies of T cells, monocytes, B cells, and NK cells were unchanged in subjects with autism as opposed to controls, suggesting that abnormal cytokines were unlikely due to altered cell numbers but might be due to altered functioning of these cells in autism. Our results support existing studies of abnormal cytokines in autism and provide comprehensive evidence of potential cellular sources of these altered cytokines in the context of autism.

Emerging Roles of T Helper Cells in Non-Infectious Neuroinflammation: Savior or Sinner

CD4⁺ T cells, also known as T helper (Th) cells, contribute to the adaptive immunity both in the periphery and in the central nervous system (CNS). At least seven subsets of Th cells along with their signature cytokines have been identified nowadays. Neuroinflammation denotes the brain’s immune response to inflammatory conditions. In recent years, various CNS disorders have been related to the dysregulation of adaptive immunity, especially the process concerning Th cells and their cytokines. However, as the functions of Th cells are being discovered, it’s also found that their roles in different neuroinflammatory conditions, or even the participation of a specific Th subset in one CNS disorder may differ, and sometimes contrast. Based on those recent and contradictory evidence, the conflicting roles of Th cells in multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, epilepsy, traumatic brain injury as well as some typical mental disorders will be reviewed herein. Research progress, limitations and novel approaches concerning different neuroinflammatory conditions will also be mentioned and compared.

Neuronal Cell Adhesion Molecules May Mediate Neuroinflammation in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by restrictive and repetitive behaviors, alongside deficits in social interaction and communication. The etiology of ASD is largely unknown but is strongly linked to genetic variants in neuronal cell adhesion molecules (CAMs), cell-surface proteins that have important roles in neurodevelopment. A combination of environmental and genetic factors are believed to contribute to ASD pathogenesis. Inflammation in ASD has been identified as one of these factors, demonstrated through the presence of proinflammatory cytokines, maternal immune activation, and activation of glial cells in ASD brains. Glial cells are the main source of cytokines within the brain and, therefore, their activity is vital in mediating inflammation in the central nervous system. However, it is unclear whether the aforementioned neuronal CAMs are involved in modulating neuroimmune signaling or glial behavior. This review aims to address the largely unexplored role that neuronal CAMs may play in mediating inflammatory cascades that underpin neuroinflammation in ASD, primarily focusing on the Notch, nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) cascades. We will also evaluate the available evidence on how neuronal CAMs may influence glial activity associated with inflammation. This is important when considering the impact of environmental factors and inflammatory responses on ASD development. In particular, neural CAM1 (NCAM1) can regulate NF-κB transcription in neurons, directly altering proinflammatory signaling. Additionally, NCAM1 and contactin-1 appear to mediate astrocyte and oligodendrocyte precursor proliferation which can alter the neuroimmune response. Importantly, although this review highlights the limited information available, there is evidence of a neuronal CAM regulatory role in inflammatory signaling. This warrants further investigation into the role other neuronal CAM family members may have in mediating inflammatory cascades and would advance our understanding of how neuroinflammation can contribute to ASD pathology.

B and T Immunoregulation: A New Insight of B Regulatory Lymphocytes in Autism Spectrum Disorder

Introduction: Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by a complex pathogenesis, by impairment social communication and interaction, and may also manifest repetitive patterns of behavior. Many studies have recognized an alteration of the immune response as a major etiological component in ASDs. Despite this, it is still unclear the variation of the function of the immune response.

Aim: Our aim is to investigate the levels of immunological markers in peripheral blood of children with ASD such as: regulatory B and T cells, memory B and natural killer (NK) cells.

Materials and Methods: We assessed various subsets of immune cells in peripheral blood (regulatory B and T cells, B-cell memory and natural killer cells) by multi-parametric flow cytometric analysis in 26 ASD children compared to 16 healthy controls (HCs) who matched age and gender.

Results: No significant difference was observed between B-cell memory and NK cells in ASDs and HCs. Instead, regulatory B cells and T cells were decreased (p < 0.05) in ASD subjects when compared to HCs.

Discussion: Regulatory B and T cells have a strategic role in maintaining the immune homeostasis. Their functions have been associated with the development of multiple pathologies especially in autoimmune diseases. According to our study, the immunological imbalance of regulatory B and T cells may play a pivotal role in the evolution of the disease, as immune deficiencies could be related to the severity of the ongoing disorder.

PM2.5 as a potential risk factor for autism spectrum disorder: Its possible link to neuroinflammation, oxidative stress and changes in gene expression

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by behavioral deficits including impairments in social communication, social interaction, and repetitive behaviors. Because the etiology of ASD is still largely unknown, there is no cure for ASD thus far. Although it has been established that genetic components play a vital role in ASD development, the influence of epigenetic regulation induced by environmental factors could also contribute to ASD susceptibility. Accumulated evidence has suggested that exposure to atmospheric particulate matter (PM) in polluted air could affect neurodevelopment, thus possibly leading to ASD. Particles with a size of 2.5 μm (PM_2.5) or less have been shown to have negative effects on human health, and could be linked to ASD symptoms in children. This review summarizes evidence from clinical and animal studies to demonstrate the possible linkage between PM_2.5 exposure and the incidence of ASD in children. An attempt was made to explore the possible mechanisms of this linkage, including changes of gene expression, oxidative stress and neuroinflammation induced by PM_2.5 exposure.

Disruption of circadian rhythm and risk of autism spectrum disorder: role of immune-inflammatory, oxidative stress, metabolic and neurotransmitter pathways

Circadian rhythms in most living organisms are regulated by light and synchronized to an endogenous biological clock. The circadian clock machinery is also critically involved in regulating and fine-tuning neurodevelopmental processes. Circadian disruption during embryonic development can impair crucial phases of neurodevelopment. This can contribute to neurodevelopmental disorders like autism spectrum disorder (ASD) in the offspring. Increasing evidence from studies showing abnormalities in sleep and melatonin as well as genetic and epigenetic changes in the core elements of the circadian pathway indicate a pivotal role of circadian disruption in ASD. However, the underlying mechanistic basis through which the circadian pathways influence the risk and progression of ASD are yet to be fully discerned. Well-recognized mechanistic pathways in ASD include altered immune-inflammatory, nitro oxidative stress, neurotransmission and synaptic plasticity, and metabolic pathways. Notably, all these pathways are under the control of the circadian clock. It is thus likely that a disrupted circadian clock will affect the functioning of these pathways. Herein, we highlight the possible mechanisms through which aberrations in the circadian clock might affect immune-inflammatory, nitro-oxidative, metabolic pathways, and neurotransmission, thereby driving the neurobiological sequelae leading to ASD.

Autism spectrum disorder in India: a scoping review

Autism is a grand challenge in global mental health to be dealt with on a priority basis. Phenotypic knowledge, biological understanding, and evidence-based intervention studies are all from western countries. We know very little about autism in the low- and middle-income countries (LMIC). Lack of infrastructure and difficulties in operationalizing research has widened the knowledge gap. We performed a comprehensive scoping review of research in Autism Spectrum Disorder in India to have an overall impression, identify gaps, and formulate evidence-based recommendations for further study. We searched PubMed, SCOPUS, and Cochrane Library to identify relevant Indian studies. A hundred and fifty-nine publications met the inclusion criteria. Most of the research contribution in autism is from few tertiary care medical centres, technological institutes, and not-for-profit organizations. We identified various themes of research like clinical profile, interventions, biomarkers, psychological, social, epidemiological, and risk factors. Evidence-based intervention studies, translation and adaptation of standard diagnostic instruments, and qualitative research on the experience of autism appeared to be state of the art. However, epidemiological studies, biomarkers identification, risk assessment studies were of low quality. There is a need for nationwide studies with representative sampling on epidemiology, biomarkers, and risk factors for a complete evaluation of the actual burden and biology of autism in India. Also, there is a need to design implementation research to evaluate the effectiveness of evidence-based interventions in routine healthcare settings. We recommend that future research should fill these gaps in understanding autism and improving its outcome in India.

Lateral septum microglial changes and behavioral abnormalities of mice exposed to valproic acid during the prenatal period

Most animal model studies of autism spectrum disorder (ASD) have been performed in males, which may be a reflex of the 3-times higher prevalence in boys than in girls. For this reason, little is known about the mechanisms underlying disease progression in females, and nothing is known about potential associations between microglial changes in the lateral septum (LS) and adult female cognition. Prenatal exposure to valproic acid (VPA) in mice has been widely used as an experimental model of autism-like behaviors associated with cellular changes. However, no study has reported the influence of VPA exposure in utero and its consequences on limbic system-dependent tasks or the microglial response in the LS in adult female mice. We compared the exploratory activity and risk assessment in novel environments of BALB/c control mice to mice exposed in utero to VPA and estimated the total number of microglia in the LS using an optical fractionator. On day 12.5 of pregnancy, females received diluted VPA or saline by gavage. After weaning, VPA exposed or control pups were separately housed in standard laboratory cages. At 5 months of age, all mice underwent behavioral testing and their brain sections were immunolabelled using IBA-1 antibody. In the open field test, VPA group showed a greater distance traveled, which was accompanied by less immobility, less time spent on the periphery and a greater number, crossed lines. Similar findings were found in the elevated plus maze test, where VPA mice traveled greater distances, immobility was significantly higher than that of control and VPA group spent less time on the closed arms of apparatus. Stereological analysis demonstrated higher microglial total number and density in the LS of VPA mice, as the cell count was greater, but the volume was similar. Therefore, we suggest that an increase in microglia in the LS may be part of the cellular changes associated with behavioral dysfunction in the VPA model of ASD.

Autism Spectrum Disorders: Role of Pre- and Post-Natal GammaDelta (γδ) T Cells and Immune Regulation

BACKGROUND

It is widely accepted that alterations in immune functioning are an important aspect of the pathoetiology and pathophysiology of autism spectrum disorders (ASD). A relatively under-explored aspect of these alterations is the role of gammaDelta (γδ) T cells, prenatally and in the postnatal gut, which seem important hubs in driving the course of ASD.

METHODS

The present article describes the role of γδ T cells in ASD, including their interactions with other immune cells shown to be altered in this spectrum of conditions, including natural killer cells and mast cells.

RESULTS

Other risk factors in ASD, such as decreased vitamins A & D, as well as toxin-associated activation of the aryl hydrocarbon receptor, may also be intimately linked to γδ T cells, and alterations in the regulation of these cells. A growing body of data has highlighted an important role for alterations in mitochondria functioning in the regulation of immune cells, including natural killer cells and mast cells. This is an area that requires investigation in γδ T cells and their putative subtypes.

CONCLUSION

It is also proposed that maternal stress may act through alterations in the maternal microbiome, leading to changes in how the balance of short-chain fatty acids, such as butyrate, which may act to regulate the placenta and foetal development. Following an overview of previous research on immune, especially γδ T cells, effects in ASD, the future research implications are discussed in detail.

Upregulation of enzymatic antioxidants in CD4+ T cells of autistic children

Autism spectrum disorder (ASD) is a neurodevelopmental disorder which begins in early childhood and presents itself with characteristic symptoms such as repetitive behavioral patterns and problems in speech/social interactions. Adaptive immune system is thought to be involved in the etiology of ASD. T cells orchestrate amplification of inflammation through release of inflammatory mediators; however, antioxidant defenses have not been evaluated in CD4⁺ T cells of ASD subjects. In this study we evaluated intracellular enzymatic antioxidant potential through measurement of major antioxidant enzymes (SOD, GPx, and GR) in ASD subjects and typically developing control (TDC) children and further assessed its role in modulation of inflammation. Our data reveal that there is an increase in antioxidant potential (SOD, GPx, GR) in CD4⁺ T cells of ASD subjects as compared to TDC children at both protein and activity level. Further, this antioxidant increase was associated with upregulated IL-17A levels in CD4⁺ T cells. This was corroborated by oxidant treatment in vitro. Pretreatment with oxidant, H₂O₂ led to attenuation of IL-17A levels along with increased oxidative stress in stimulated CD4⁺ T cells from ASD subjects. These data reveal that antioxidant play an essential role in modulation of inflammatory potential in CD4⁺ T cells of ASD subjects.

Dysregulation in IL-6 receptors is associated with upregulated IL-17A related signaling in CD4+ T cells of children with autism

Autism spectrum disorder (ASD) is a heterogeneous syndrome characterized by dysregulations in speech and social interactions as well as repetitive and stereotypical behavioral patterns in which immune system plays a significant role. IL-6, an essential cytokine for polarization of Th0 cells into Th17 cells has been demonstrated to be crucial in the etiology of ASD in past studies both in humans and mice. Th17 cells are also believed to be central players in the pathogenesis of ASD through release of IL-17A. However, there is still insufficient data regarding identification of Th17 cells with respect to IL-6 signaling in ASD subjects. Therefore, this study explored IL-6 receptors (IL-6R/sIL-6R) and Th17 (p-STAT3/IL-17A/IL-23R) related markers comprehensively in the blood of typically-developing control (TDC, n = 35) and ASD children (n = 45). Our data show that there is enhanced sIL-6R levels in plasma and CD4+ T cells of ASD subjects as compared to TDC group. Increased sIL-6R signaling is associated with upregulated Th17 development in ASD subjects. Further, severe ASD subjects have higher inflammation in terms of IL-6/IL-17A related signaling as compared to moderate ASD patients. Furthermore, treatment of CD4 + T cells in vitro with IL-6 leads to much greater upregulation of p-STAT3, and IL-17A in ASD subjects than similarly treated CD4+ T cells in TDC group. Antagonism of IL-6 signaling by SC144 in vitro led to blockade of IL-6 mediated effects on CD4+ T cells. These data display unequivocally that IL-6 signaling components are dysregulated which play a crucial in enhancement of Th17 development in ASD subjects.

Resveratrol in Autism Spectrum Disorders: Behavioral and Molecular Effects

Resveratrol (RSV) is a polyphenolic stillbenoid with significant anti-oxidative and anti-inflammatory properties recently tested in animal models of several neurological diseases. Altered immune alteration and oxidative stress have also been found in patients with autism spectrum disorders (ASD), and these alterations could add to the pathophysiology associated with ASD. We reviewed the current evidence about the effects of RSV administration in animal models and in patients with ASD. RSV administration improves the core-symptoms (social impairment and stereotyped activity) in animal models and it also displays beneficial effects in other behavioral abnormalities such as hyperactivity, anxiety and cognitive function. The molecular mechanisms by which RSV restores or improves behavioral abnormalities in animal models encompass both normalization of central and peripheral immune alteration and oxidative stress markers and new molecular mechanisms such as expression of cortical gamma-amino butyric acid neurons, certain type of miRNAs that regulate spine growth. One randomized, placebo-controlled clinical trial (RCT) suggested that RSV add-on risperidone therapy improves comorbid hyperactivity/non-compliance, whereas no effects where seen in core symptoms of ASD No RCTs about the effect of RSV as monotherapy have been performed and the results from preclinical studies encourage its feasibility. Further clinical trials should also identify those ASD patients with immune alterations and/or with increased oxidative stress markers that would likely benefit from RSV administration.

T cell populations in children with autism spectrum disorder and co-morbid gastrointestinal symptoms

Children with ASD are more likely to experience gastrointestinal (GI) symptoms than typically-developed children. Numerous studies have reported immune abnormalities and inflammatory profiles in the majority of individuals with ASD. Immune dysfunction is often hypothesized as a driving factor in many GI diseases and it has been suggested that it is more apparent in children with ASD that exhibit GI symptoms. In this study we sought to characterize peripheral T cell subsets in children with and without GI symptoms, compared to healthy typically-developing children. Peripheral blood mononuclear cells were isolated from participants, who were categorized into three groups: children with ASD who experience GI symptoms (n ​= ​14), children with ASD who do not experience GI symptoms (n ​= ​10) and typically-developing children who do not experience GI symptoms (n ​= ​15). In order to be included in the GI group, GI symptoms such as diarrhea, constipation, and/or pain while defecating, had to be present in the child regularly for the past 6 months; likewise, in order to be placed in the no GI groups, bowel movements could not include the above symptoms present throughout development. Cells were assessed for surface markers and intracellular cytokines to identify T cell populations. Children with ASD and GI symptoms displayed elevated TH17 populations (0.757% ​± ​0.313% compared to 0.297% ​± ​0.197), while children with ASD who did not experience GI symptoms showed increased frequency of TH2 populations (2.02% ​± ​1.08% compared to 1.01% ​± ​0.58%). Both ASD groups showed evidence of reduced gut homing regulatory T cell populations compared to typically developing children (ASDGI:1.93% ​± ​0.75% and ASDNoGI:1.85% ​± ​0.89 compared to 2.93% ​± ​1.16%). Children with ASD may have deficits in immune regulation that lead to differential inflammatory T cell subsets that could be linked to associated co-morbidities.

Th17 and MAIT cell mediated inflammation in antipsychotic free schizophrenia patients

The immune hypothesis of schizophrenia has gained significant popularity in recent years in schizophrenia research. Evidence suggests that the peripheral immune system communicates with central nervous system and the effect propagates through microglial and lymphocyte crosstalk, especially during neuro-inflammation. Although, there is previous literature indicating changes in lymphocyte population in schizophrenia, detailed studies with respect to T and B cells are scarce. Mucosal associated invariant T (MAIT) cells are functionally associated with the gut microbiome. The gut microbiome has been implicated in the pathogenesis of schizophrenia. However, there is no information on the frequency of MAIT cells in schizophrenia. Hence, we investigated changes in proportions of T cells, B cells and MAIT cells in peripheral blood mononuclear cells derived from antipsychotic-free patients with schizophrenia in comparison to healthy controls. In line with earlier reports, we noted perturbations in T_h17 cells. This study for the first time reports changes in frequencies of MAIT cells in a homogenous population of antipsychotic-free patients with schizophrenia. These changes, though not common across all patients nevertheless point to the fact that inflammation is prevalent in a significant subset of schizophrenia cases.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Serum cytokine levels in children with spectrum autism disorder: Differences in pro- and anti-inflammatory balance

BACKGROUND

Autism Spectrum Disorders (ASDs) is a developmental and neurological disorder that affects all aspects of social communication, with limited and stereotypical interest, and atypical responses to sensory stimuli. Diagnosis of ASD is currently phenotype based with no reliable laboratory test available to assist clinicians. Researches have shown that individuals with autism often exhibit dysfunction of cytokines.

METHODS

A total of 42 patients with ASD and 20 matched controls participants were recruited for the study. Diagnosis was conducted by medical specialists and based on the International Classification of Mental and Behavioral Disorders - ICD-10, DSM-5 and CARS sore. Whole blood samples were collected and serum IL's and chemokin levels were made using ELISA kits.

RESULTS

Results demonstrated that in comparison to the controls, the individuals with autism showed significantly higher concentration of IL-1β, IL-4, IL-6 and IL-13. We also demonstrated significant correlations between the levels of cytokines which implies the presence of an interactive network between them. The results of ROC analysis indicated the 4-factors (IL-1β, IL-4, IL-6 and IL-13) could be potential biomarkers in diagnosis of ASD.

CONCLUSIONS

In this study, serum levels of cytokine differed among children with ASD. However, the findings of this support the possibility of using an appropriate selection of serum cytokine for the diagnosis ASD and emphasize the need to standardize quantitative methods for serum analysis.

The influence of neuroinflammation in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterised by deficits in social communication and restricted or repetitive behaviours. The clinical presentation of ASD is highly variable and diagnosis is based on the presence of impaired social communication and repetitive and/or restricted behaviours. Although the precise pathophysiologies underlying ASD are unclear, growing evidence supports a role for dysregulated neuroinflammation. The potential involvement of microglia and astrocytes reactive to inflammatory stimuli in ASD has generated much interest due to their varied roles including in mounting an immune response and regulating synaptic function. Increased numbers of reactive microglial and astrocytes in both ASD postmortem tissue and animal models have been reported. Whether dysregulation of glial subtypes exacerbates alterations in neural connectivity in the brain of autistic patients is not well explored. A role for the gut-brain axis involving microbial-immune-neuronal cross talk is also a growing area of neuroinflammation research. Greater understanding of these interactions under patho/physiological conditions and the identification of consistent immune profile abnormalities can potentially lead to more reliable diagnostic measures and treatments in ASD.

Autism Associated With Anti-NMDAR Encephalitis: Glutamate-Related Therapy

The purpose of this review is to correlate autism with autoimmune dysfunction in the absence of an explanation for the etiology of autism spectrum disorder. The anti-N-methyl-D-aspartate receptor (anti-NMDAR) autoantibody is a typical synaptic protein that can bind to synaptic NMDA glutamate receptors, leading to dysfunctional glutamate neurotransmission in the brain that manifests as psychiatric symptoms (psychosis, hallucinations, and personality changes). Detection of autoantibodies, cytokines, decreased lymphocytes, serum immunoglobulin level imbalance, T-cell mediated immune profile, maternal infection history, and children's infection history can all be vital biological markers of autoimmune autism. Diagnosing autoimmune encephalitis sooner can increase the effectiveness of curative treatments-such as immune therapy or immune modulatory therapy-that may prevent the long-term consequence of being misdiagnosed with autism spectrum disorder. Glutamate therapy primarily normalizes glutamate neurotransmission and can be a new add-on intervention alongside antipsychotics for treating autoimmune autism.