Study of Novel Autoantibodies in Schizophrenia

Autoantibodies against acetylcholine receptors are increased in archived serum samples from patients with schizophrenia

Previous studies have demonstrated that the levels of IgG against neurotransmitter receptors are increased in patients with schizophrenia. Genome-wide association (GWA) studies of schizophrenia confirmed that 108 loci harbouring over 300 genes were associated with schizophrenia. Although the functional implications of genetic variants are unclear, theoretical functional alterations of these genes could be replicated by the presence of autoantibodies. This study examined the levels of plasma IgG antibodies against four neurotransmitter receptors, CHRM4, GRM3, CHRNA4 and CHRNA5, using an in-house ELISA in 247 patients with schizophrenia and 344 non-psychiatric controls. Four peptides were designed based on in silico analysis with computational prediction of HLA-DRB1 restricted and B-cell epitopes. The relationship between plasma IgG levels and psychiatric symptoms, as defined by the Operational Criteria Checklist for Psychotic Illness and Affective Illness (OPCRIT), were examined. The results showed that the levels of plasma IgG against peptides derived from CHRM4 and CHRNA4 were significantly increased in patients with schizophrenia compared with control subjects, but there was no significant association of plasma IgG levels with any symptom domain or any specific symptoms. These preliminary results suggest that CHRM4 and CHRNA4 may be novel targets for autoantibody responses in schizophrenia, although the pathogenic relationship between increased serum autoantibody levels and schizophrenia symptoms remains unclear.

DNA Hyper-methylation Associated With Schizophrenia May Lead to Increased Levels of Autoantibodies

Background and Hypothesis

Environmental stressors may influence immune surveillance in B lymphocytes and stimulate autoimmune responses via epigenetic DNA methylation modifications in schizophrenia (SCZ).

Study Design

A total of 2722, Chinese Han origin subjects were recruited in this study (2005-2011), which included a discovery follow-up cohort with 40 remitters of SCZ (RSCZ), 40 nonremitters of SCZ (NRSCZ), and 40 controls (CTL), and a replication follow-up cohort (64 RSCZ, 16 NRSCZ, and 84 CTL), as well as a case-control validation cohort (1230 SCZ and 1208 CTL). Genomic DNA methylation, target gene mRNA transcripts, and plasma autoantibody levels were measured across cohorts.

Study Results

We found extensive differences in global DNA methylation profiles between RSCZ and NRSCZ groups, wherein differential methylation sites (DMS) were enriched with immune cell maturation and activation in the RSCZ group. Out of 2722 participants, the foremost DMS cg14341177 was hyper-methylated in the SCZ group and it inhibited the alternative splicing of its target gene BICD2 and may have increased its autoantigen exposure, leading to an increase in plasma anti-BICD2 IgG antibody levels. The levels of cg14341177 methylation and anti-BICD2 IgG decreased significantly in RSCZ endpoint samples but not in NRSCZ endpoint samples. There are strong positive correlations between cg14341177 methylation, anti-BICD2 IgG, and positive and negative syndrome scale (PANSS) scores in the RSCZ groups, but not in the NRSCZ groups.

Conclusions

These data suggest that abnormal DNA methylation could affect autoreactive responses in SCZ, and that cg14341177 methylation and anti-BICD2 IgG levels may potentially serve as useful biomarkers.

Schizophrenia as autoimmune disease: Involvement of Anti-NCAM antibodies

Understanding the etiopathogenesis of schizophrenia has always been an unsolved puzzle for modern medicine. This seems to be due to both disease complexity and lack of sufficient knowledge regarding the biological and non-biological anomalies that exhibit schizophrenia subjects. However, dysregulated immunity is a commonly identified feature in affected individuals. Thus, recently, a hallmark study showed causality relationship between anti-NCAM antibodies and schizophrenia-related behaviors in mice. NCAM plays crucial role in neurodevelopment during early life and neuroplasticity against different stressors during adulthood, and its dysfunction in schizophrenia is increasingly proven. The present review provides the main evidence that support the contribution of autoimmunity and NCAM abnormalities in the development of schizophrenia. Furthermore, it introduces five hypotheses that may explain the mechanism by which anti-NCAM antibodies are produced in the context of schizophrenia: (i) molecular mimicry, (ii) gut dysbiosis, (iii) viral infection, (iv) exposure to environmental pollutants, (v) and NCAM production anomalies.

Inhibitory effects of circulating natural autoantibodies to CD47-derived peptides on OSCC cells

OBJECTIVES

Natural autoantibodies serve as an important anti-tumorigenic component in the body. This study was thus designed to investigate whether circulating natural IgG autoantibodies against a cluster of differentiation 47 (CD47) could exert inhibitory effects on oral squamous cell carcinoma (OSCC).

SUBJECTS AND METHODS

The expression levels of 13 tumor-targeted genes in three OSCC cell lines were analyzed by qPCR, and CD47 expression in OSCC tissues was also verified with IHC staining. An in-house ELISA was performed to analyze circulating anti-CD47 IgG levels in control subjects, oral benign tumor, and OSCC patients, and to detect anti-CD47 IgG-abundant plasma. Three OSCC cell lines were treated with anti-CD47 IgG-abundant and -deficient plasma, respectively, followed by the analysis of cell proliferation, apoptosis, and invasion/metastasis.

RESULTS

The CD47 gene showed the highest expression among 13 genes detected in three OSCC cell lines; its expression was significantly higher in OSCC tissues than adjacent tissues. Plasma anti-CD47 IgG levels showed the differences between control subjects, oral benign tumor, and OSCC patients. Anti-CD47 IgG-abundant plasma could evidently reduce cell viability via suppressing p-AKT expression and inducing cell apoptosis and inhibit the invasion of all three OSCC cell lines.

CONCLUSIONS

Natural autoantibodies against CD47 may be a potential agent for OSCC immunotherapy.

An examination of plasma autoantibodies against voltage gated calcium channels in schizophrenia

Autoantibodies targeting the central nervous system have been shown to induce psychiatric symptoms resembling schizophrenia. Concurrently, genetic studies have characterised a number of risk variants associated with schizophrenia although their functional implications are largely unknown. Any biological effects of functional variants on protein function may potentially be replicated by the presence of autoantibodies against such proteins. Recent research has demonstrated that the R1346H variant in the CACNA1I gene coding for the Cav 3.3 protein results in a synaptic reduction of Cav3.3 voltage gated calcium channels and, consequently, sleep spindles, which have been shown to correlate with several symptom domains in patients with schizophrenia. The present study measured plasma levels of IgG against two peptides derived from CACNA1I and CACNA1C, respectively, in patients with schizophrenia and healthy controls. The results demonstrated that increased anti-CACNA1I IgG levels were associated with schizophrenia but not associated with any symptom domain related to the reduction of sleep spindles. In contrast to previously published work indicating that inflammation may be a marker for a depressive phenotype, plasma levels of IgG against either CACNA1I or CACNA1C peptides were not associated with depressive symptoms, suggesting that anti-Cav3.3 autoantibodies may function independently of pro-inflammatory processes.

The SFT2D2 gene is associated with the autoimmune pathology of schizophrenia in a Chinese population

Background

The relative risk of GWAS-confirmed loci strongly associated with schizophrenia may be underestimated due to the decay of linkage disequilibrium between index SNPs and causal variants. This study is aimed to investigate schizophrenia-associated signals detected in the 1q24-25 region in order to identify a causal variant in LD with GWAS index SNPs, and the potential biological functions of the risk gene.

Methods

Re-genotyping analysis was performed in the 1q24-25 region that harbors three GWAS index SNPs associated with schizophrenia (rs10489202, rs11586522, and rs6670165) in total of 9801 case-control subjects of Chinese Han origin. Circulating autoantibody levels were assessed using an in-house ELISA against a protein derived fragment encoded by SFT2D2 in total of 682 plasma samples.

Results

A rare variant (rs532193193) in the SFT2D2 locus was identified to be strongly associated with schizophrenia. Compared with control subjects, patients with schizophrenia showed increased anti-SFT2D2 IgG levels. Receiver operating characteristic (ROC) analysis revealed an area under the ROC curve (AUC) of 0.803 with sensitivity of 28.57% against specificity of 95% for the anti-SFT2D2 IgG assay.

Discussion

Our findings indicate that SFT2D2 is a novel gene for risk of schizophrenia, while endogenous anti-SFT2D2 IgG may underlie the pathophysiology of the immunological aspects of schizophrenia.

Cytokines as Potential Biomarkers of Clinical Characteristics of Schizophrenia

Immune activation plays a major role in the pathogenesis of schizophrenia, as confirmed by many studies, systematic reviews, and meta-analyses. The important role of neuroinflammation in the formation of the relation between impaired neurobiological processes and schizophrenia psychopathology is being actively discussed. We quantified serum concentrations of 22 cytokines in 236 patients with schizophrenia and 103 mentally and somatically healthy individuals by a multiplex assay. We found higher TGF-α (p = 0.014), IFN-γ (p = 0.036), IL-5 (p < 0.001), IL-6 (p = 0.047), IL-8 (p = 0.005), IL-10 (p <0.001), IL-15 (p = 0.007), IL-1RA (p = 0.007), and TNF-α (p < 0.001) levels in patients with schizophrenia than in healthy individuals. Subgroup analysis revealed a much greater number of statistically significant differences in cytokine levels among females than among males. Patients with a continuous course of schizophrenia showed statistically significantly higher levels of IL-12p70 (p = 0.019), IL-1α (p = 0.046), and IL-1β (p = 0.035) compared with patients with an episodic course. Most cytokines were positively correlated with positive, general, and total PANSS scores. In patients with a duration of schizophrenia of 10 years or more, the level of IL-10 was higher than that in patients with a disease duration of 5 years or less (p = 0.042). Thus, an imbalance in cytokines was revealed in patients with schizophrenia, depending on sex and clinical characteristics of the disease.

Vogt-Koyanagi-Harada Disease Presenting as a Schizophrenia Spectrum Disorder: A Case Report

Introduction: Numerous autoimmune disorders accompany with psychosis. The Vogt-Koyanagi-Harada (VKH) disease is an autoimmune disease with no reports about its concomitance with psychosis so far. Case Presentation: We report the co-occurrence of schizophrenic spectrum diseases with VKH for the first time. They have common manifestations such as aggression, agitation, and self-talking, subsiding after chemotherapy. Workup evaluation was performed by computed tomography (CT) scan, magnetic resonance imaging (MRI), electroencephalography (EEG), lumbar puncture (LP) study, IQ test, lab tests for hepatitis and other infections, and retinal angiography and sonography. The patient underwent corticosteroid therapy, immunosuppressive therapy, risperidone, propranolol, and trihexyphenidyl. Conclusions: Our results showed the significant role of autoimmunity in the genesis of psychosis. On the other hand, unusual manifestations and slow response to treatment in these patients show that autoimmune disorders with psychosis may worsen the prognosis of psychosis.

Toll-Like Receptor 4 Gene Polymorphisms and Susceptibility to Schizophrenia: A Case-Control Study

Schizophrenia is a common psychiatric disorder that exhibits a variety of symptoms. The exact etiology and pathogenesis are still doubtful. However, genetic and environmental factors seem to have a role. Years ago, the role of the immune system was focused on auto-antibodies, cytokines, different types of immune cells and immune genes. The Toll-like receptors (TLR) are a cornerstone of the innate immune system, particularly TLR4. TLR4 primarily recognises gram-negative lipopolysaccharides bacteria. This case-control study, for the first time to our knowledge, examined the role of TLR4 gene polymorphisms in 142 Egyptian schizophrenic patients and 175 healthy controls. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), four single nucleotide polymorphisms (SNPs) were investigated in the TLR4 gene rs11536889, rs10759931, rs1927911, and rs1927914. The Positive and Negative Syndrome Scale (PANSS) was used in diagnosis and assessment. A statistically significant association was observed between rs11536889, rs1927911 and rs1927914, but no association was found between rs10759931. There was no association between the different SNP genotypes and PANSS, except between rs1927914 and general psychopathologic symptoms. This study shows a strong association between TLR4 rs11356889 and rs1927911 minor alleles and schizophrenia. These findings could be additional evidence for the immune system's role in schizophrenia development. However, more studies with a more significant sample number, TLR4 protein assessment, and a larger number of SNPs are recommended.

Skewing of the Antibody Repertoire in Cerebrospinal Fluid B Cells from Healthy Controls and Patients with Schizophrenia

Autoantibodies play a role in the etiology of some neuropsychiatric disorders. To address the possibility that B cells and their antibodies may be involved in the pathophysiology of schizophrenia, we examined B cells in cerebrospinal fluid (CSF) and peripheral blood (PB) of 4 schizophrenic patients (SP) and 4 healthy control (HC) volunteers by analyzing immunoglobulin VH gene usage. All CSF samples contained measurable levels of B cells. We found for both SP and HC, CSF B cells represented a select subset of, and were not the same as, B cells in PB. Moreover, we found statistically significant differences in antibodies generated by CSF B cells in SP compared to CSF B cells in HC. Although binding characteristics of CSF SP-associated B cell antibodies is unknown, the study number is small, and pathophysiology has not been established, these results suggest the value of focusing further study on the distinctly separate population of CSF B cells in SP.

Immune System Abnormalities in Schizophrenia: An Integrative View and Translational Perspectives

The immune system is generally known to be the primary defense mechanism against pathogens. Any pathological conditions are reflected in anomalies in the immune system parameters. Increasing evidence suggests the involvement of immune dysregulation and neuroinflammation in the pathogenesis of schizophrenia. In this systematic review, we summarized the available evidence of abnormalities in the immune system in schizophrenia. We analyzed impairments in all immune system components and assessed the level of bias in the available evidence. It has been shown that schizophrenia is associated with abnormalities in all immune system components: from innate to adaptive immunity and from humoral to cellular immunity. Abnormalities in the immune organs have also been observed in schizophrenia. Evidence of increased C-reactive protein, dysregulation of cytokines and chemokines, elevated levels of neutrophils and autoantibodies, and microbiota dysregulation in schizophrenia have the lowest risk of bias. Peripheral immune abnormalities contribute to neuroinflammation, which is associated with cognitive and neuroanatomical alterations and contributes to the pathogenesis of schizophrenia. However, signs of severe inflammation are observed in only about 1/3 of patients with schizophrenia. Immunological parameters may help identify subgroups of individuals with signs of inflammation who well respond to anti-inflammatory therapy. Our integrative approach also identified gaps in knowledge about immune abnormalities in schizophrenia, and new horizons for the research are proposed.

Decreased BOLD signals elicited by 40-Hz auditory stimulation of the right primary auditory cortex in bipolar disorder: An fMRI study

BACKGROUND

A number studies have been conducted on abnormalities in the cortical circuitry of gamma oscillations, including deficit in auditory steady-state response (ASSR) to gamma-frequency (≧ 30-Hz) stimulation, in patients with bipolar disorder (BD). In the current study, we investigated neural responses during click stimulation by blood oxygen level-dependent (BOLD) signals. We focused on Broadman 41 and 42, the main sources of ASSR.

MATERIALS AND METHODS

We acquired BOLD responses elicited by click trains of 80-, 40-, 30- and 20-Hz frequencies from 25 patients with BD to 27 healthy controls (HC) with normal hearing between 22 and 59 years of age assessed via a standard general linear-model-based analysis. We extracted contrast values by identifying the primary auditory cortex and Brodmann areas 41 and 42 as regions of interest (ROI)s.

RESULTS

BD group showed significantly decreased ASSR-BOLD signals in response to 40-Hz stimuli compared to the HC group in the right Brodmann areas 41 and 42. We found significant negative correlations between the BOLD change in the right Brodmann areas 41 and 42 and Structured Interview Guide for the Hamilton Depression Rating Scale (SIGH-D) scores, also the BOLD change in the right Brodmann areas 41 and 42 and the Positive and Negative Syndrome Scale (PANSS)-Negative scores.

CONCLUSION

The observed decrease in BOLD signal patterns in the right primary auditory cortex during 40-Hz ASSR may be a potential biomarker option for bipolar disorder.

Autoantibody profiles associated with clinical features in psychotic disorders

Autoimmune processes are suspected to play a role in the pathophysiology of psychotic disorders. Better understanding of the associations between auto-immunoglobulin G (IgG) repertoires and clinical features of mental illness could yield novel models of the pathophysiology of psychosis, and markers for biological patient stratification. We undertook cross-sectional detection and quantification of auto-IgGs in peripheral blood plasma of 461 people (39% females) with established psychotic disorder diagnoses. Broad screening of 24 individuals was carried out on group level in eight clinically defined groups using planar protein microarrays containing 42,100 human antigens representing 18,914 proteins. Autoantibodies indicated by broad screening and in the previous literature were measured using a 380-plex bead-based array for autoantibody profiling of all 461 individuals. Associations between autoantibody profiles and dichotomized clinical characteristics were assessed using a stepwise selection procedure. Broad screening and follow-up targeted analyses revealed highly individual autoantibody profiles. Females, and people with family histories of obesity or of psychiatric disorders other than schizophrenia had the highest overall autoantibody counts. People who had experienced subjective thought disorder and/or were treated with clozapine (trend) had the lowest overall counts. Furthermore, six autoantibodies were associated with specific psychopathology symptoms: anti-AP3B2 (persecutory delusions), anti-TDO2 (hallucinations), anti-CRYGN (initial insomnia); anti-APMAP (poor appetite), anti-OLFM1 (above-median cognitive function), and anti-WHAMMP3 (anhedonia and dysphoria). Future studies should clarify whether there are causal biological relationships, and whether autoantibodies could be used as clinical markers to inform diagnostic patient stratification and choice of treatment.

MAD1L1 and TSNARE gene polymorphisms are associated with schizophrenia susceptibility in the Han Chinese population

BACKGROUND

Schizophrenia (SCZ) is a severe mental illness with high heritability. This study aimed to explore the correlation between MAD1L1, TSNARE polymorphisms and SCZ susceptibility.

METHODS

A total of 493 SCZ patients and 493 healthy controls were included. The genotypes of MAD1L1 and TSNARE polymorphisms were identified by Agena MassARRAY platform. Odds ratio (OR) and 95% confidence intervals (CIs) were tested via logistic regression analysis in multiple genetic models and different subgroups.

RESULTS

We observed that AG genotype of rs1107592, AG genotype of rs4976976, and CA genotype of rs67756423 decreased the susceptibility to SCZ (p < 0.05). Age stratification analysis showed that the TC genotype of rs12666575, AG genotype of rs1107592, and AG genotype of rs4976976 decreased the risk of SCZ individuals older than 36 years (p < 0.05). In addition, the AG and AA genotype of rs4976976, the CA genotype of rs67756423 were associated with a lower risk of SCZ in males (p < 0.05). In females, the TT genotype of rs12666575 in recessive model, the AG and AA-AG genotype of rs1107592 in heterozygote and dominant model, could reduce the susceptibility to SCZ (p < 0.05). However, no significant association was found after Bonferroni correction.

CONCLUSIONS

Our results suggest that MAD1L1 and TSNARE genetic polymorphisms exert a protective role in the risk of SCZ. These findings provide evidence that MAD1L1 and TSNARE may serve as potential biomarkers of SCZ. However, a replication experiment in a cohort with large sample size are required to confirm our findings. Trial registration Not applicable.

Molecular signature of extracellular matrix pathology in schizophrenia

Growing evidence points to a critical involvement of the extracellular matrix (ECM) in the pathophysiology of schizophrenia (SZ). Decreases of perineuronal nets (PNNs) and altered expression of chondroitin sulphate proteoglycans (CSPGs) in glial cells have been identified in several brain regions. GWAS data have identified several SZ vulnerability variants of genes encoding for ECM molecules. Given the potential relevance of ECM functions to the pathophysiology of this disorder, it is necessary to understand the extent of ECM changes across brain regions, their region- and sex-specificity and which ECM components contribute to these changes. We tested the hypothesis that the expression of genes encoding for ECM molecules may be broadly disrupted in SZ across several cortical and subcortical brain regions and include key ECM components as well as factors such as ECM posttranslational modifications and regulator factors. Gene expression profiling of 14 neocortical brain regions, caudate, putamen and hippocampus from control subjects (n = 14/region) and subjects with SZ (n = 16/region) was conducted using Affymetrix microarray analysis. Analysis across brain regions revealed widespread dysregulation of ECM gene expression in cortical and subcortical brain regions in SZ, impacting several ECM functional key components. SRGN, CD44, ADAMTS1, ADAM10, BCAN, NCAN and SEMA4G showed some of the most robust changes. Region-, sex- and age-specific gene expression patterns and correlation with cognitive scores were also detected. Taken together, these findings contribute to emerging evidence for large-scale ECM dysregulation in SZ and point to molecular pathways involved in PNN decreases, glial cell dysfunction and cognitive impairment in SZ.

Impaired blood-brain barrier in the microbiota-gut-brain axis: Potential role of bipolar susceptibility gene TRANK1

Bipolar disorder (BD) is a common psychiatric illness with high prevalence and disease burden. Accumulating susceptibility genes for BD have been identified in recent years. However, the exact functions of these genes remain largely unknown. Despite its high heritability, gene and environment interaction is commonly accepted as the major contributing factor to BD pathogenesis. Intestine microbiota is increasingly recognized as a critical environmental factor for human health and diseases via the microbiota‐gut‐brain axis. BD individuals showed altered diversity and compositions in the commensal microbiota. In addition to pro‐inflammatory factors, such as interleukin‐6 and tumour necrosis factor‐α, type 1 interferon signalling pathway is also modulated by specific intestinal bacterial strains. Disruption of the microbiota‐gut‐brain axis contributes to peripheral and central nervous system inflammation, which accounts for the BD aetiology. Administration of type 1 interferon can induce the expression of TRANK1, which is associated with elevated circulating biomarkers of the impaired blood‐brain barrier in BD patients. In this review, we focus on the influence of intestine microbiota on the expression of bipolar gene TRANK1 and propose that intestine microbiota‐dependent type 1 interferon signalling is sufficient to induce the over‐expression of TRANK1, consequently causing the compromise of BBB integrity and facilitating the entrance of inflammatory mediators into the brain. Activated neuroinflammation eventually contributes to the occurrence and development of BD. This review provides a new perspective on how gut microbiota participate in the pathogenesis of BD. Future studies are needed to validate these assumptions and develop new treatment targets for BD.

Exploring autoantibody signatures in brain tissue from patients with severe mental illness

In recent years, studies have shown higher prevalence of autoantibodies in patients with schizophrenia compared to healthy individuals. This study applies an untargeted and a targeted affinity proteomics approach to explore and characterize the autoantibody repertoire in brain tissues from 73 subjects diagnosed with schizophrenia and 52 control subjects with no psychiatric or neurological disorders. Selected brain tissue lysates were first explored for IgG reactivity on planar microarrays composed of 11,520 protein fragments representing 10,820 unique proteins. Based on these results of ours and other previous studies of autoantibodies related to psychosis, we selected 226 fragments with an average length of 80 amino acids, representing 127 unique proteins. Tissue-based analysis of IgG reactivities using antigen suspension bead arrays was performed in a multiplex and parallel fashion for all 125 subjects. Among the detected autoantigens, higher IgG reactivity in subjects with schizophrenia, as compared to psychiatrically healthy subjects, was found against the glutamate ionotropic receptor NMDA type subunit 2D (anti-GluN2D). In a separate cohort with serum samples from 395 young adults with a wider spectrum of psychiatric disorders, higher levels of serum autoantibodies targeting GluN2D were found when compared to 102 control individuals. By further validating GluN2D and additional potential autoantigens, we will seek insights into how these are associated with severe mental illnesses.

Analysis of plasma autoantibodies for inflammatory cytokines in patients with first-episode schizophrenia among a Chinese population

Neuroinflammation has been considered to be involved in the development of schizophrenia. This study aimed to study circulating autoantibodies for inflammatory cytokines in first-episode schizophrenia. A total of 181 patients and 197 controls were recruited for detection of plasma IgG antibodies against peptide antigens derived from interleukin 1α (IL1α), IL1ß, IL6, IL8 and tumour necrosis factor alpha (TNFα). The major finding was that patients with schizophrenia had significantly higher levels of anti-IL1ß IgG, anti-IL6 IgG and anti-IL8 IgG, and a significantly lower level of anti-IL1α IgG. This study suggests that inflammatory response may contribute to the development of schizophrenia.

Further Study of Circulating Antibodies to P16, CD25 and FOXP3 in Hepatocellular Carcinoma

Purpose

It has been reported that circulating levels of IgG antibodies against p16, CD25 and FOXP3 proteins were significantly changed in patients with lung cancer, breast cancer and esophageal cancer. However, different peptide fragments appear to trigger different immune responses. This work aimed to analyze the alteration of plasma IgG for p16-derived peptide antigen called p16a, CD25-derived peptide antigen called CD25a and a FOXP3-derived antigen in hepatocellular carcinoma (HCC).

Patients and methods

An enzyme-linked immunosorbent assay (ELISA) was developed in-house to detect plasma IgG to p16a, CD25a and FOXP3 in 119 patients with HCC and 132 control subjects.

Results

Circulating levels of IgG antibodies for all three peptide antigens were significantly higher in HCC patients than control subjects (P<0.001 for all 3 assays); male patients mainly contributed to increase (P<0.01 for all 3 assays). Further analysis showed that plasma anti-p16a, anti-CD25a and anti-FOXP3 IgG levels were increased mainly in patients with intermediate and late-stage HCC (P<0.01 for both assays). Receiver operating characteristic (ROC) curve analysis showed that with a specificity of >95%, the area under the ROC curve (AUC) was 0.62 with 11.4% sensitivity for anti-p16a assay, 0.68 with 14.3% sensitivity for anti-CD25a IgG assay and 0.64 with 10.1% sensitivity for anti-FOXP3 assay. Of the three groups of HCC patients, group 3 (BCLC stage C+D) showed the best sensitivity for the detection of plasma anti-p16a and anti-FOXP3 IgG levels with an AUC of 0.66 and 0.65.

Conclusion

Circulating IgG antibody to p16a, CD25a and FOXP3 proteins may be a useful biomarker for assessment of HCC prognosis of this malignancy, especially in male patients with HCC.

Anti-TSNARE1 IgG plasma levels differ by sex in patients with schizophrenia in a Chinese population

It was recently reported that levels of plasma IgG antibodies against peptide antigens derived from proteins encoded by schizophrenia-associated genes are altered in individuals with schizophrenia treated with antipsychotics. This study aimed to replicate the initial finding in antipsychotic-naïve patients with first-episode schizophrenia and to explore the possible mechanism by which immune tolerance of B cells may be altered in this disease. A total of 408 case-control plasma samples were collected for analysis of circulating IgG antibodies against fragments derived from TCF4, TSNARE1, ZNF804A, TRANK1, ERCC4, DPYD and CD25 using an in-house ELISA. The Mann-Whitney U-test revealed that patients with schizophrenia had a significant change in plasma anti-TSNARE1 and anti-CD25 IgG levels; male patients mainly contributed to the increased levels of anti-TSNARE1 IgG and anti-CD25 IgG. Receiver operating characteristic (ROC) curve analysis revealed that the anti-TSNARE1 IgG assay had an area under the ROC curve of 0.625 with a sensitivity of 15.7% and a specificity of 95.2%. Work on a B-cell model revealed that TRANK1-derived antigen treatments could enhance the proportions of CD83+ cells and apoptotic B cells when compared with TSNARE1-derived antigen and vehicle treatment. We conclude that there is a gender difference in autoimmune responses in schizophrenia and suggest that anti-TSNARE1 IgG may be indicative of schizophrenia in a subgroup of male patients.

B-cells and schizophrenia: A promising link or a finding lost in translation?

Recent genetic studies have suggested a potential role for B-cells in the pathogenesis of schizophrenia. Greater insight in the functioning of B-cells in patients with schizophrenia is therefore of importance. In this narrative review we aim to give an overview of the current literature on B-cells and schizophrenia. We found no evidence for altered numbers of these cells in blood. We did find support for increased levels of B-cell related cytokines and certain autoantibodies. Studies on B-cell development and function, or their numbers in cerebrospinal fluid or brain tissue are very limited. Based on the available data we appraise whether various B-cell mediated pathological mechanisms are likely to play a role in schizophrenia and provide directions for future research.

Neutrophil-to-lymphocyte ratio in schizophrenia: A systematic review and meta-analysis

BACKGROUND

The immune system appears to be dysregulated in schizophrenia (SZ). The potential prognostic or diagnostic value of neutrophil-to-lymphocyte ratio (NLR), an inexpensive proxy marker for a wide spectrum of conditions, has not been established in SZ. We seek to investigate a) whether NLR is increased in SZ patients, b) if this difference in more prominent in relapsed SZ or first-episode psychosis.

METHODS

A structured algorithm was applied in MEDLINE (1946-2018), PsychInfo, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL) (1999-2018), PSYNDEX (1984-2017) and Clinicaltrials.gov (2008-2018) databases.

RESULTS

Through the database search, 1023 articles were screened. Ten studies (804 SZ patients, 671 controls) were included in the meta-analysis. In SZ patients, the NLR was increased by 0.65 (95% CI: 0.54, 0.86, p < 10^-5). This difference was significant in both acute relapse and first-episode psychosis subgroups. Studies of moderate and high quality also showed a significant NLR increase in SZ patients (I² = 0%). Meta-regression analysis showed that the polymorphonuclear count and antipsychotic use may confound the result. In leave-one-out meta-analysis, no study altered the significance of the result when omitted.

CONCLUSIONS

NLR in SZ patients is increased, both in chronic disease and in first-episode psychosis. Baseline characteristics, such as polymorphonuclear count and antipsychotic use, may affect its accuracy. The application of this marker in clinical practice requires the description of its normal values in the general population, its potential change after antipsychotic administration and its correlation with disease activity. A large-scale, prospective study design would resolve these issues.

A study of anti-gliadin antibodies in first-episode patients with schizophrenia among a Chinese population

A recent study suggested that digestion-resistant peptides derived from wheat gluten (mainly gliadin) could induce the secretion of anti-gliadin IgG antibodies in patients with schizophrenia. This research was then designed to replicate this initial finding in 134 drug-naïve patients with first-episode schizophrenia and 160 healthy controls. An enzyme-linked immunosorbent assay was developed in-house with 8 gliadin-derived peptide antigens to test anti-gliadin IgG antibodies in the circulation. The results showed that schizophrenia patients had significantly higher levels of plasma anti-AL2G2 IgG and anti-ABO3a IgG than healthy controls. Based on the specificity of 95%, anti-AL2G2 IgG assay had a sensitivity of 12.7% and anti-ABO3a IgG assay had a sensitivity of 17.2% for anti-ABO3a IgG assay. Increased levels of anti-AL2G2 and anti-ABC3a IgG antibodies were not correlated with total IgG levels in either the patient group or the control group. In conclusion, circulating IgG against AL2G2 and ABO3a may be useful biomarkers for identification of a gluten-sensitive subgroup of schizophrenia in the Chinese population although the present results are rather different from the work performed in a British population.

VRK2, a Candidate Gene for Psychiatric and Neurological Disorders

Recent large-scale genetic approaches, such as genome-wide association studies, have identified multiple genetic variations that contribute to the risk of mental illnesses, among which single nucleotide polymorphisms (SNPs) within or near the vaccinia related kinase 2 (VRK2) gene have gained consistent support for their correlations with multiple psychiatric and neurological disorders including schizophrenia (SCZ), major depressive disorder (MDD), and genetic generalized epilepsy. For instance, the genetic variant rs1518395 in VRK2 showed genome-wide significant associations with SCZ (35,476 cases and 46,839 controls, p = 3.43 × 10-8) and MDD (130,620 cases and 347,620 controls, p = 4.32 × 10-12) in European populations. This SNP was also genome-wide significantly associated with SCZ in Han Chinese population (12,083 cases and 24,097 controls, p = 3.78 × 10-13), and all associations were in the same direction of allelic effects. These studies highlight the potential roles of VRK2 in the central nervous system, and this gene therefore might be a good candidate to investigate the shared genetic and molecular basis between SCZ and MDD, as it is one of the few genes known to show genome-wide significant associations with both illnesses. Furthermore, the VRK2 gene was found to be involved in multiple other congenital deficits related to the malfunction of neurodevelopment, adding further support for the involvement of this gene in the pathogenesis of these neurological and psychiatric illnesses. While the precise function of VRK2 in these conditions remains unclear, preliminary evidence suggests that it may affect neuronal proliferation and migration via interacting with multiple essential signaling pathways involving other susceptibility genes/proteins for psychiatric disorders. Here, we have reviewed the recent progress of genetic and molecular studies of VRK2, with an emphasis on its role in psychiatric illnesses and neurological functions. We believe that attention to this important gene is necessary, and further investigations of VRK2 may provide hints into the underlying mechanisms of SCZ and MDD.

Circulating anti-p16a IgG autoantibodies as a potential prognostic biomarker for non-small cell lung cancer

It has been reported that p16 protein is overexpressed in many types of solid cancer and its aberrant expression may trigger the immune response, leading to the secretion of anti‐p16 antibodies. Here, we developed an in‐house ELISA with three p16‐derived linear peptide antigens to examine plasma anti‐p16 antibody levels in patients with non‐small cell lung cancer (NSCLC). Blood samples were taken from 200 control subjects and 211 patients with NSCLC prior to anticancer therapy. A Mann–Whitney U test demonstrated that plasma anti‐p16a IgG levels were significantly higher in NSCLC patients than in control subjects (Z = −11.14, P < 0.001). However, neither plasma anti‐p16b nor plasma anti‐p16c IgG levels showed significant differences in patients with NSCLC as compared to control subjects. Moreover, further analysis indicated that anti‐p16a IgG levels increased with tumor stages, and patients with late stage NSCLC, namely group IV, had the highest IgG levels among four subgroups. Receiver operating characteristic analysis revealed that the anti‐p16a IgG assay had a sensitivity of 32.7% against a specificity of 95.0% in group IV, while Kaplan–Meier survival analysis revealed no significant difference in overall survival between patients with high anti‐p16a IgG levels and those with low anti‐p16a IgG levels (χ² = 0.24, P = 0.63). In conclusion, anti‐p16a IgG may be suitable for use as a prognostic biomarker for NSCLC.

Alteration of circulating natural autoantibodies to CD25-derived peptide antigens and FOXP3 in non-small cell lung cancer

Natural autoantibody is a key component for immune surveillance function. Regulatory T (Treg) cells play indispensable roles in promoting tumorigenesis via immune escape mechanisms. Both CD25 and FOXP3 are specific markers for Treg cells and their natural autoantibodies may be involved in anticancer activities. This work was designed to develop an in-house enzyme-linked immunosorbent assay (ELISA) to examine plasma natural IgG against CD25 and FOXP3 in non-small cell lung cancer (NSCLC). Compared with control subjects, NSCLC patients had significantly higher levels of plasma IgG for CD25a (Z = -8.05, P < 0.001) and FOXP3 (Z = -4.17, P < 0.001), lower levels for CD25b (Z = -3.58, P < 0.001), and a trend toward lower levels for CD25c (Z = -1.70, P = 0.09). Interestingly, the anti-CD25b IgG assay had a sensitivity of 25.0% against a specificity of 95.0% in an early stage patients (T1N0M0) who showed the lowest anti-CD25b IgG levels among 4 subgroups classified based on staging information. Kaplan-Meier survival analysis showed that patients with high anti-FOXP3 IgG levels had shorter survival than those with low anti-FOXP3 IgG levels (χ2 = 3.75, P = 0.05). In conclusion, anti-CD25b IgG may be a promising biomarker in terms of screening individuals at high risk of lung cancer.

Plasma anti-BIRC5 IgG may be a useful marker for evaluating the prognosis of nonsmall cell lung cancer

A recent study demonstrated that circulating levels of IgG antibodies against linear peptide antigens derived from baculoviral IAP repeat-containing protein 5 isoform 2 (BIRC5) and myc proto-oncogene protein (MYC) were significantly increased in nonsmall cell lung cancer (NSCLC). This study was undertaken to replicate this initial work in an independent sample. An enzyme-linked immunosorbent assay (ELISA) was developed in-house to examine plasma IgG antibodies for three linear peptide antigens derived from BIRC5a, BIRC5b, and MYC in 211 patients with NSCLC and 200 control subjects. A Mann-Whitney U-test demonstrated that plasma anti-BIRC5a IgG levels, but not anti-BIRC5b or anti-MYC IgG levels, were significantly higher in NSCLC patients than control subjects, especially in male patients. Both squamous cell cancer and adenocarcinoma showed increased anti-BIRC5a IgG levels, but the IgG levels were not found to be changed significantly in the early stage of NSCLC. Kaplan-Meier survival analysis showed that NSCLC patients with high anti-BIRC5b IgG levels had better prognosis and longer overall survival (OS) than patients with low anti-BIRC5b IgG levels, although this significant difference failed to survive the adjustment for age, gender, NSCLC stages, and types. Plasma anti-BIRC5a and MYC IgG levels did not show significant associations with OS. In conclusion, Plasma anti-BIRC5 IgG may be a useful marker for assessment of prognosis of NSCLC but not for early diagnosis of this malignancy.