The relationship between serum cytokine levels and degree of psychosis in patients with schizophrenia

Current Strategies and Future Directions of Wearable Biosensors for Measuring Stress Biochemical Markers for Neuropsychiatric Applications

Most wearable biosensors aimed at capturing psychological state target stress biomarkers in the form of physical symptoms that can correlate with dysfunction in the central nervous system (CNS). However, such markers lack the specificity needed for diagnostic or preventative applications. Wearable biochemical sensors (WBSs) have the potential to fill this gap, however, the technology is still in its infancy. Most WBSs proposed thus far target cortisol. Although cortisol detection is demonstrated as a viable method for approximating the extent and severity of psychological stress, the hormone also lacks specificity. Multiplex WBSs that simultaneously target cortisol alongside other viable stress-related biochemical markers (SBMs) can prove to be indispensable for understanding how psychological stress contributes to the pathophysiology of neuropsychiatric illnesses (NPIs) and, thus, lead to the discovery of new biomarkers and more objective clinical tools. However, none target more than one SBM implicated in NPIs. Till this review, cortisol's connection to dysfunctions in the CNS, to other SBMs, and their implication in various NPIs has not been discussed in the context of developing WBS technology. As such, this review is meant to inform the biosensing and neuropsychiatric communities of viable future directions and possible challenges for WBS technology for neuropsychiatric applications.

Adiponectin, resistin, interleukin-4 and TGF-β2 levels in treatment resistant schizophrenia patients

BACKGROUND

The aim of the present study was to measure adiponectin, resistin, interleukin-4 and TGF-β levels in first episode, treatment resistant patients with schizophrenia.

METHODS

In total, fifty-three treatment-resistant patients were included in the study. In subgroups of these patients, we measured Interleukin-4 (IL-4), Tumor Growth Factor-β2 (TGF-β2), adiponectin and resistin levels at three different timepoints: in the drug-naïve state, after two rounds of treatment with different antipsychotic drugs for a total of 16 weeks and, after clozapine treatment for 12 weeks.

RESULTS

TGF-β2 and adiponectin levels decreased after treatment with olanzapine and risperidone, while resistin and IL-4 levels did not differ significantly.Comparing the levels of the aforementioned cytokines before the initiation and after clozapine treatment, we found an even greater decrease in adiponectin levels while resistin and IL-4 levels significantly increased and TGF-β2 levels did not differ significantly.

CONCLUSIONS

We report elevated resistin and IL-4 levels and decreased adiponectin levels in first-episode, treatment resistant schizophrenia patients after clozapine treatment. These findings may be at least partly due to the anti-inflammatory action of clozapine, although sub-clinical metabolic disturbances may also have played a role as far as resistin and adiponectin are concerned. In a subgroup of these patients we report reduced TGF-β2 and adiponectin levels after two unsuccessful trials with risperidone and olanzapine comparing them with the ones of the same subgroup in the drug-naïve phase.

The Causal Relationships Between Inflammatory Proteins, Brain Structure, and Psychiatric Disorders: A Two-Step Mendelian Randomization Analysis

BACKGROUND AND HYPOTHESIS

Inflammatory proteins are implicated in psychiatric disorders, but the causality and underlying mechanisms remain unclear.

STUDY DESIGN

We conducted bidirectional Mendelian randomization (MR) using genetic variants from genome-wide association studies (GWAS) for 91 inflammatory proteins (N = 14 824) and 11 psychiatric disorders (N = 9725 to 1 035 760). The primary analysis used the inverse variance weighted (IVW) method, with additional sensitivity analyses to confirm robustness. A two-step MR approach assessed whether brain imaging-derived phenotypes (IDPs) mediated the observed effects.

STUDY RESULTS

Forward MR analysis found the protective effect of CD40 on schizophrenia (SCZ) (IVW OR = 0.90, P = 5.29 × 10-6) and bipolar disorder (BD) (IVW OR = 0.89, P = 5.08 × 10-6). Reverse MR demonstrated that increased genetic risk of Tourette's syndrome (TS) was associated with reduced Fms-associated tyrosine kinase 3 ligand (Flt3L) levels (Flt3L) (Wald Ratio beta = -0.42, P = 1.99 × 10-7). The protective effect of CD40 on SCZ was partially mediated by the modulation of fractional anisotropy (FA) values in the right and left superior frontal occipital fasciculus, with mediation proportions of 9.6% (P = .025) and 11.5% (P = .023), respectively.

CONCLUSION

CD40 exerts an immunoprotective effect on SCZ and BD, and the effect of CD40 on SCZ was partially mediated through modulation of FA values in the superior frontal occipital fasciculus. These findings enhance comprehension of the etiology of these psychiatric conditions and underscore the promise of therapeutic strategies aimed at inflammatory proteins.

Blood-derived factors to brain communication in brain diseases

Brain diseases, mainly including acute brain injuries, neurodegenerative diseases, and mental disorders, have posed a significant threat to human health worldwide. Due to the limited regenerative capability and the existence of the blood-brain barrier, the brain was previously thought to be separated from the rest of the body. Currently, various cross-talks between the central nervous system and peripheral organs have been widely described, including the brain-gut axis, the brain-liver axis, the brain-skeletal muscle axis, and the brain-bone axis. Moreover, several lines of evidence indicate that leveraging systemic biology intervention approaches, including but not limited to lifestyle interventions, exercise, diet, blood administration, and peripheral immune responses, have demonstrated a significant influence on the progress and prognosis of brain diseases. The advancement of innovative proteomic and transcriptomic technologies has enriched our understanding of the nuanced interplay between peripheral organs and brain diseases. An array of novel or previously underappreciated blood-derived factors have been identified to play pivotal roles in mediating these communications. In this review, we provide a comprehensive summary of blood-to-brain communication following brain diseases. Special attention is given to the instrumental role of blood-derived signals, positing them as significant contributors to the complex process of brain diseases. The insights presented here aim to bridge the current knowledge gaps and inspire novel therapeutic strategies for brain diseases.

Changes in IL-6, IL-12, IL-5, IL-10 and TGF-β1 Concentration in Patients with Treatment-Resistant Schizophrenia (TRS) Following Electroconvulsive Therapy (ECT)-A Pilot Study

Background/Objectives: Treatment-resistant schizophrenia (TRS) may be considered as a neuro-immune disorder. Electroconvulsive therapy (ECT) remains an important therapeutic option for patients with TRS, however, its impact on cytokine profile is barely investigated. Therefore, this study attempts to establish associations between serum cytokines IL-6, IL-12, IL-5, IL-10 and TGF-β1 changes (pre- and post-ECT) and the effectiveness of ECT in TRS patients. The second aim is to search for correlations between serum concentrations of the above specified cytokines and psychometric assessments of clinical schizophrenia symptoms. Methods: The cytokine concentrations were measured in eight TRS patients on psychopharmacological treatment prior to and following ECT and in 13 control subjects. Psychopathology assessment was based on the Positive and Negative Syndrome Scale (PANSS). Results: Prior to ECT, IL-10 concentration was significantly higher in TRS patients, while IL-5 was decreased in comparison to the controls. A significant concentration decrease in the pro-inflammatory cytokines IL-6 (p = 0.012), IL-12 (p = 0.049) and anti-inflammatory IL-10 (p = 0.012) post-ECT vs. pre-ECT was observed, whereas concentrations of IL-5 and TGF-β1 did not significantly change. Also, a significant decrease in schizophrenia symptoms measured by the PANSS post-ECT was found. Furthermore, the pattern of correlations between PANSS scores and cytokine concentrations was different when comparing levels pre- and post-ECT. Additionally, correlations between changes in PANSS scores and cytokine concentrations were found. Conclusions: These results may indicate the probable impact of electroconvulsive therapy on the balance between pro- and anti-inflammatory cytokines, which may correspond to a neurobiological therapeutic effect of ECT in TRS patients.

Differential inflammatory profiles in carriers of reciprocal 22q11.2 copy number variants

BACKGROUND

Genetic copy number variants (CNVs; i.e., a deletion or duplication) at the 22q11.2 locus confer increased risk of neuropsychiatric disorders and immune dysfunction. Inflammatory profiles of 22q11.2 CNV carriers can shed light on gene-immune relationships that may be related to neuropsychiatric symptoms. However, little is known about inflammation and its relationship to clinical phenotypes in 22q11.2 CNV carriers. Here, we investigate differences in peripheral inflammatory markers in 22q11.2 CNV carriers and explore their relationship with psychosis risk symptoms and sleep disturbance.

METHODS

Blood samples and clinical assessments were collected from 22q11.2 deletion (22qDel) carriers (n=45), 22q11.2 duplication (22qDup) carriers (n=29), and typically developing (TD) control participants (n=92). Blood plasma levels of pro-inflammatory cytokines, including interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), and anti-inflammatory cytokine interleukin-10 (IL-10) were measured using a MesoScale Discovery multiplex immunoassay. Plasma levels of C-reactive protein (CRP) were measured using Enzyme-linked Immunosorbent Assay (ELISA). Linear mixed effects models controlling for age, sex, and body mass index were used to: a) examine group differences in inflammatory markers between 22qDel, 22qDup, and TD controls, b) test differences in inflammatory markers between 22qDel carriers with psychosis risk symptoms (22qDelPS+) and those without (22qDelPS-), and c) conduct an exploratory analysis testing the effect of sleep disturbance on inflammation in 22qDel and 22qDup carriers. A false discovery rate correction was used to correct for multiple comparisons.

RESULTS

22qDup carriers exhibited significantly elevated levels of IL-8 relative to TD controls (q<0.001) and marginally elevated IL-8 levels relative to 22qDel carriers (q=0.08). There were no other significant differences in inflammatory markers between the three groups (q>0.13). 22qDelPS+ exhibited increased levels of IL-8 relative to both 22qDelPS- (q=0.02) and TD controls (p=0.002). There were no relationships between sleep and inflammatory markers that survived FDR correction (q>0.14).

CONCLUSION

Our results suggest that CNVs at the 22q11.2 locus may have differential effects on inflammatory processes related to IL-8, a key mediator of inflammation produced by macrophages and microglia. Further, these IL-8-mediated inflammatory processes may be related to psychosis risk symptoms in 22qDel carriers. Additional research is required to understand the mechanisms contributing to these differential levels of IL-8 between 22q11.2 CNV carriers and IL-8's association with psychosis risk.

Elevated serum IL-17 A and CCL20 levels as potential biomarkers in major psychotic disorders: a case-control study

BACKGROUND

Major psychotic disorders (MPD), including schizophrenia (SCZ) and schizoaffective disorder (SAD), are severe neuropsychiatric conditions with unclear causes. Understanding their pathophysiology is essential for better diagnosis, treatment, and prognosis. Recent research highlights the role of inflammation and the immune system, particularly the Interleukin 17 (IL-17) family, in these disorders. Elevated IL-17 levels have been found in MPD, and human IL-17 A antibodies are available. Changes in chemokine levels, such as CCL20, are also noted in SCZ. This study investigates the relationship between serum levels of IL-17 A and CCL20 in MPD patients and their clinical characteristics.

METHOD

We conducted a case-control study at the Ibn Sina Psychiatric Hospital (Mashhad, Iran) in 2023. The study involved 101 participants, of which 71 were MPD patients and 30 were healthy controls (HC). The Positive and Negative Symptom Scale (PANSS) was utilized to assess the symptoms of MPD patients. Serum levels of CCL20 and IL-17 A were measured using Enzyme-Linked Immunosorbent Assay (ELISA) kits. We also gathered data on lipid profiles and Fasting Blood Glucose (FBS).

RESULTS

The mean age of patients was 41.04 ± 9.93 years. The median serum levels of CCL20 and IL-17 A were significantly elevated in MPD patients compared to HC (5.8 (4.1-15.3) pg/mL and 4.2 (3-5) pg/mL, respectively; p < 0.001). Furthermore, CCL20 and IL-17 A levels showed a positive correlation with the severity of MPD. MPD patients also had significantly higher FBS, cholesterol, and Low-Density Lipoprotein (LDL) levels, and lower High-Density Lipoprotein (HDL) levels compared to HC. No significant relationship was found between PANSS components and blood levels of IL17 and CCL20.

CONCLUSION

The current study revealed that the serum levels of IL-17 A and CCL20 in schizophrenia patients are higher than those in the control group. Metabolic factors such as FBS, cholesterol, HDL, and LDL also showed significant differences between MPD and HC. In conclusion, the findings suggest that these two inflammatory factors could serve as potential therapeutic targets and prognostic biomarkers for schizophrenia.

Association between psychiatric admissions in patients with schizophrenia and IL-6 plasma levels polygenic score

Schizophrenia diagnosis and admission history were associated with a polygenic score (PGS) for schizophrenia based on a subset of variants that act by modifying the expression of genes whose expression is also modified by antipsychotics. This gene set was enriched in cytokine production. Interleukin-6 (IL-6) is the only cytokine whose plasma levels were associated both with schizophrenia diagnosis and with acute decompensations in the largest meta-analysis. Therefore, we hypothesized that an IL-6 PGS, but not other cytokines PGSs, would be associated with schizophrenia chronicity/psychiatric admissions. Using the IL-6 PGS model from The PGS Catalog, IL-6 PGS was calculated in 427 patients with schizophrenia and data regarding admission history. Association between IL-6 PGS and chronicity, measured as number and duration of psychiatric admissions, or ever readmission was analyzed by multivariate ordinal and logistic regression, respectively. Specificity of results was assessed by analysis of PGSs from the other cytokines at The PGS Catalog with meta-analytic evidence of association with schizophrenia diagnosis or acute decompensations, IL-1RA, IL-4, IL-8, and IL-12. IL-6 PGS was associated with schizophrenia chronicity, explaining 1.51% of variability (OR = 1.29, 95% CI 1.07-1.55, P = 0.007). There was no association with ever readmission. Other cytokines PGSs were not associated with chronicity. Association with IL-6 PGS was independent of association with schizophrenia PGS. Our results provide evidence that genetically regulated higher levels of IL-6 are involved in schizophrenia chronicity, highlighting the relevance of immunity processes for a subgroup of patients.

Elevated levels of oxLDL and LOX-1: Implications for schizophrenia pathophysiology

Inflammation and oxidative stress are both considered to be factors in the etiopathogenesis of schizophrenia. LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1) and ox-LDL (oxidized low-density lipoprotein) have been reported to be active in neuroinflammation pathways in which they are involved in oxidative stress and inflammation. However, its relationship with schizophrenia is unclear. This study aimed to assess the potential connection between serum ox-LDL and LOX-1 levels in schizophrenia patients, their unaffected first-degree relatives, and healthy controls. The study comprised 63 schizophrenia patients, 57 first-degree relatives, and 63 healthy controls who were age, gender, and BMI-matched. Serum ox-LDL and LOX-1 levels were measured. PANSS was used to assess the severity of the disease. Levels of both ox-LDL and LOX-1 were markedly elevated in individuals diagnosed with schizophrenia when compared to both their relatives and a control group. While ox-LDL levels were significantly higher in relatives of patients compared to controls, there was no significant difference between relatives of patients and control groups for LOX-1 levels. Significant correlations were observed between PANNS general and total and ox-LDL levels and PANNS negative and LOX-1 levels. The relationship between ox-LDL and LOX-1 and schizophrenia is quite limited in the literature and is a new field of study. Future studies are needed to evaluate their role in etiopathogenesis.

The Interrelationships between Cytokines and Schizophrenia: A Systematic Review

Schizophrenia (SCZ) imposes a significant burden on patients and their families because of its high prevalence rate and disabling nature. Given the lack of definitive conclusions regarding its pathogenesis, physicians heavily rely on patients' subjective symptom descriptions for diagnosis because reliable diagnostic biomarkers are currently unavailable. The role of the inflammatory response in the pathogenesis of SCZ has been supported by some studies. The findings of these studies showed abnormal changes in the levels of inflammatory factors, such as cytokines (CKs), in both peripheral blood and cerebrospinal fluid (CSF) among individuals affected by SCZ. The findings imply that inflammatory factors could potentially function as risk indicators for the onset of SCZ. Consequently, researchers have directed their attention towards investigating the potential utility of CKs as viable biomarkers for diagnosing SCZ. Extracellular vesicles (EVs) containing disease-specific components exhibit remarkable stability and abundance, making them promising candidates for biomarker discovery across various diseases. CKs encapsulated within EVs secreted by immune cells offer valuable insights into disease progression. This review presents a comprehensive analysis summarizing the relationship between CKs and SCZ and emphasizes the vital role of CKs encapsulated within EVs in the pathogenesis and development of SCZ.

Association between neutrophil to high-density lipoprotein cholesterol ratio (NHR) and depression symptoms among the United States adults: a cross-sectional study

BACKGROUND

Depression acts as a noteworthy worldwide public health challenge. Identifying accessible biomarkers is crucial for early diagnosis and intervention. The relationship between depression in adult Americans and the neutrophil to high-density lipoprotein cholesterol ratio (NHR) was investigated in this research.

METHODS

The relationship between NHR and depressive symptoms was analyzed utilizing National Health and Nutrition Examination Survey data from 2005 to 2018 and the Patient Health Questionnaire-9. The study included 33,871 participants with complete NHR and depression data. Adjusted multivariable logistic regression models were used to account for possible confounders, and subgroup analyses were conducted to investigate effect changes.

RESULTS

Elevated NHR levels were positively correlated with a heightened risk of depression (OR = 1.03, 95% CI: 1.01-1.05, P < 0.0005). After the NHR was divided into tertiles, those in the top tertile had an 18% higher chance of developing depression than those in the bottom tertile (OR = 1.18; 95% CI: 1.05-1.32; P for trend = 0.0041). Subgroup analyses revealed variations in this association based on race and marital status. Additionally, the relationship between NHR and depression demonstrated a U-shaped pattern, with a significant breakpoint identified at an NHR of 6.97.

CONCLUSION

These results imply that the NHR may be a potential biomarker for depression risk, with implications for early detection and personalized treatment. Further research is needed to elucidate the mechanisms underlying the NHR-depression link and establish causality.

The associations of peripheral interleukin alterations and hippocampal subfield volume deficits in schizophrenia

The hippocampus is one of the brain regions most vulnerable to inflammatory insults, and the relationships between peripheral inflammation and hippocampal subfields in patients with schizophrenia remain unclear. In this study, forty-six stably medicated patients with schizophrenia and 48 demographically matched healthy controls (HCs) were recruited. The serum levels of IL - 1β, IL-6, IL-10, and IL-12p70 were measured, and 3D high-resolution T1-weighted magnetic resonance imaging was performed. The IL levels and hippocampal subfield volumes were both compared between patients and HCs. The associations of altered IL levels with hippocampal subfield volumes were assessed in patients. Patients with schizophrenia demonstrated higher serum levels of IL-6 and IL-10 but lower levels of IL-12p70 than HCs. In patients, the levels of IL-6 were positively correlated with the volumes of the left granule cell layer of the dentate gyrus (GCL) and cornu Ammonis (CA) 4, while the levels of IL-10 were negatively correlated with the volumes of those subfields. IL-6 and IL-10 might have antagonistic roles in atrophy of the left GCL and CA4. This suggests a complexity of peripheral cytokine dysregulation and the potential for its selective effects on hippocampal substructures, which might be related to the pathophysiology of schizophrenia.

Circulating inflammatory cytokines influencing schizophrenia: a Mendelian randomization study

Introduction

Schizophrenia (SCZ) is a severe psychiatric disorder whose pathophysiology remains elusive. Recent investigations have underscored the significance of systemic inflammation, particularly the impact of circulating inflammatory proteins, in SCZ.

Methods

This study explores the potential causal association between certain inflammatory proteins and SCZ. Bidirectional Mendelian randomization (MR) analyses were conducted utilizing data from expansive genome-wide association studies (GWAS). Data regarding circulating inflammatory proteins were sourced from the GWAS Catalog database, encompassing 91 inflammatory cytokines. SCZ-related data were derived from the Finngen database, incorporating 47,696 cases and 359,290 controls. Analytical methods such as inverse variance weighted, MR-Egger, weighted median, simple mode, and weighted mode were employed to evaluate the association between inflammatory cytokines and SCZ. Sensitivity analyses were also performed to affirm the robustness of the results.

Results

Following FDR adjustment, significant associations were observed between levels of inflammatory cytokines, including Fibroblast Growth Factor 5 (OR = 1.140, 95%CI = 1.045, 1.243, p = 0.003, FDR=0.015), C-C Motif Chemokine 4 (OR = 0.888, 95%CI = 0.816, 0.967, p = 0.006, FDR = 0.015), C-X-C Motif Chemokine 1 (OR = 0.833, 95%CI = 0.721, 0.962, p = 0.013, FDR = 0.064), and C-X-C Motif Chemokine 5 (OR = 0.870, 95%CI = 0.778, 0.973, p = 0.015, FDR = 0.074), and the risk of SCZ.

Conclusion

Our results from MR analysis suggest a potential causal link between circulating inflammatory cytokines and SCZ, thereby enriching our understanding of the interactions between inflammation and SCZ. Furthermore, these insights provide a valuable foundation for devising therapeutic strategies targeting inflammation.

Haloperidol, Olanzapine, and Risperidone Induce Morphological Changes in an In Vitro Model of Human Hippocampal Neurogenesis

BACKGROUND

Induced pluripotent stem cell (iPSC) based neuronal differentiation is valuable for studying neuropsychiatric disorders and pharmacological mechanisms at the cellular level. We aimed to examine the effects of typical and atypical antipsychotics on human iPSC-derived neural progenitor cells (NPCs).

METHODS

Proliferation and neurite outgrowth were measured by live cell imaging, and gene expression levels related to neuronal identity were analyzed by RT-QPCR and immunocytochemistry during differentiation into hippocampal dentate gyrus granule cells following treatment of low- and high-dose antipsychotics (haloperidol, olanzapine, and risperidone).

RESULTS

Antipsychotics did not modify the growth properties of NPCs after 3 days of treatment. However, the characteristics of neurite outgrowth changed significantly in response to haloperidol and olanzapine. After three weeks of differentiation, mRNA expression levels of the selected neuronal markers increased (except for MAP2), while antipsychotics caused only subtle changes. Additionally, we found no changes in MAP2 or GFAP protein expression levels as a result of antipsychotic treatment.

CONCLUSIONS

Altogether, antipsychotic medications promoted neurogenesis in vitro by influencing neurite outgrowth rather than changing cell survival or gene expression. This study provides insights into the effects of antipsychotics on neuronal differentiation and highlights the importance of considering neurite outgrowth as a potential target of action.

Correlation of Immune-Inflammatory Response System (IRS)/Compensatory Immune-Regulatory Reflex System (CIRS) with White Matter Integrity in First-Episode Patients with Schizophrenia

Several studies have reported compromised white matter integrity, and that some inflammatory mediators may underlie this functional dysconnectivity in the brain of patients with schizophrenia. The immune-inflammatory response system and compensatory immune-regulatory reflex system (IRS/CIRS) are novel biomarkers for exploring the role of immune imbalance in the pathophysiological mechanism of schizophrenia. This study aimed to explore the little-known area regarding the composite score of peripheral cytokines, the IRS/CIRS, and its correlation with white matter integrity and the specific microstructures most affected in schizophrenia. First-episode patients with schizophrenia (FEPS, n = 94) and age- and sex-matched healthy controls (HCs, n = 50) were enrolled in this study. Plasma cytokine levels were measured using enzyme-linked immunosorbent assay (ELISA), and psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). The whole brain white matter integrity was measured by fractional anisotropy (FA) from diffusion tensor imaging (DTI) using a 3-T Prisma MRI scanner. The IRS/CIRS in FEPS was significantly higher than that in HCs (p = 1.5 × 10-5) and Cohen's d effect size was d = 0.74. FEPS had a significantly lower whole-brain white matter average FA (p = 0.032), which was negatively associated with IRS/CIRS (p = 0.029, adjusting for age, sex, years of education, BMI, and total intracranial volume), but not in the HCs (p > 0.05). Among the white matter microstructures, only the cortico-spinal tract was significantly correlated with IRS/CIRS in FEPS (r =  - 0.543, p = 0.0009). Therefore, elevated IRS/CIRS may affect the white matter in FEPS.

Association of cytokines levels, psychopathology and cognition among CR-TRS patients with metabolic syndrome

Clozapine-resistant treatment-refractory schizophrenia (CR-TRS) patients face significant clinical challenges. While links between metabolic syndrome (MetS) and inflammatory cytokines in schizophrenia have been established, the relationship between MetS and cytokine levels in CR-TRS patients remains unexplored. This study aimed to investigate the relationship between cytokines levels, clinical symptoms and cognitive impairments in CR-TRS patients, both with and without MetS. The study included 69 CR-TRS patients (31with MetS and 38 without MetS) and 84 healthy controls. The levels of IL-2, IL-6, TNF-α and routine biochemical parameters were measured. Psychopathological symptoms and cognitive function were assessed using the Positive and Negative Syndrome Scale (PANSS) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), respectively. We found that CR-TRS patients with MetS displayed lower cognitive function scores compared to those without MetS, even when accounting for potential confounders. TNF-α levels were significantly higher in CRTRS patients with MetS compared to those without MetS, demonstrating substantial pathophysiological potential for CR-TRS patients with MetS via receiver operating characteristic curve (ROC). In CR-TRS patients without MetS, IL-2 independently contributed to the total score and general psychopathology subscore of PANSS. Additionally, IL-6 exhibited an independent contribution to the positive subscore of PANSS. In terms of cognition function, IL-6 independently contributed to the delayed memory of RBANS in CR-TRS patients without MetS. TNF-α could potentially serve as a predictive marker for distinguishing between CR-TRS patients with/without MetS, while IL-2 and IL-6 could independently contribute to psychopathological symptoms or cognitive function in CRTRS patients without MetS. Our study provided insights into the potential interplay between cytokines, clinical symptoms and cognitive impairments in CR-TRS patients with/without MetS.

Serum autoantibodies against α7-nicotinic receptors in subgroups of patients with bipolar disorder or schizophrenia: clinical features and link with peripheral inflammation

There is growing evidence that autoantibodies (AAbs) against proteins expressed in the brain are playing an important role in neurological and psychiatric disorders. Here, we explore the presence and the role of peripheral AAbs to the α7-nicotinic acetylcholine receptor (nAChR) in inflammatory subgroups of psychiatric patients with bipolar disorder (BD) or schizophrenia (SCZ) and healthy controls. We have identified a continuum of AAb levels in serum when employing a novel ELISA technique, with a significant elevation in patients compared to controls. Using unsupervised two-step clustering to stratify all the subjects according to their immuno-inflammatory background, we delineate one subgroup consisting solely of psychiatric patients with severe symptoms, high inflammatory profile, and significantly increased levels of anti-nAChR AAbs. In this context, we have used monoclonal mouse anti-human α7-nAChR antibodies (α7-nAChR-mAbs) and shown that TNF-α release was enhanced upon LPS stimulation in macrophages pre-incubated with α7-nAChR-mAbs compared to the use of an isotype control. These findings provide a basis for further study of circulating nicotinic AAbs, and the inflammatory profile observed in patients with major mood and psychotic disorders.

Effects of IL-6/IL-6R axis alterations in serum, plasma and cerebrospinal fluid with the schizophrenia: an updated review and meta-analysis of 58 studies

Studies investigating the association between IL-6/IL-6R axis and schizophrenia (SZ) susceptibility found inconsistent data. To reconcile the results, a systematic review followed by a meta-analysis was performed to assess the associations. This study followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A comprehensive search of the literature was carried out in July 2022 using electronic databases PubMed, EBSCO, Science Direct, PsychInfo, and Scopus. Study quality was assessed by the Newcastle-Ottawa scale. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by fixed-effect or random-effect model analysis. Fifty-eight studies were identified, including 4,200 SZ patients and 4,531 controls. Our meta-analysis results showed an increase of IL-6 levels in plasma, serum, or CSF and decreased IL-6R levels in serum in patients under treatment. Further studies are needed to better elucidate the correlation between the IL-6/IL-6R axis and the schizophrenia.

Interaction between peripheral and central immune markers in clinical high risk for psychosis

Neuroinflammatory events prior to the diagnosis of schizophrenia may play a role in transition to illness. To date only one in-vivo study has investigated this association between peripheral proinflammatory cytokines and brain markers of inflammation (e.g., mitochondrial 18 kDa translocator protein, TSPO) in schizophrenia, but none in its putative prodrome. In this study, we primarily aimed to (Barron et al., 2017) test study group (clinical high-risk (CHR) and healthy controls) differences in peripheral inflammatory markers and test for any associations with symptom measures, (Hafizi et al., 2017a) investigate the interaction between brain TSPO levels (dorsolateral prefrontal cortex (DLPFC) and hippocampus) and peripheral inflammatory clusters (entire cohort and (CHR) group independently) within a relatively large group of individuals at CHR for psychosis (N = 38) and healthy controls (N = 20). Participants underwent structural brain magnetic resonance imaging (MRI) and TSPO [18F]FEPPA positron emission tomography (PET) scans. Serum samples were assessed for peripheral inflammatory markers (i.e., CRP and interleukins). For exploratory analysis, we aimed to examine cluster differences for symptom measures and identify independent peripheral predictors of brain TSPO expression. Here, we report increased IL-8 levels that are positively correlated with prodromal general symptom severity and showed trend-level association with apathy in CHR. We identified distinct inflammatory clusters characterized by inflammatory markers (IL-1 β, IL-2, IFN-γ) that were comparable between entire cohort and CHR. TSPO levels did not differ between inflammatory clusters (entire cohort or CHR). Finally, we show that CRP, IL-1 β, TNF-α, and IFN-γ levels were the independent peripheral predictors of brain TSPO expression. Thus, alterations in brain TSPO expression in response to inflammatory processes are not evident in CHR. Taken together, clustering by inflammatory status is a promising strategy to characterize the interaction between brain TSPO and peripheral markers of inflammation.

Inflammatory disequilibrium and lateral ventricular enlargement in treatment-resistant schizophrenia

Treatment-resistant schizophrenia (TRS) patient respond poorly to antipsychotics. Inflammatory imbalance involving pro- and anti-inflammatory cytokines may play an important role in the mechanism of antipsychotic-medication response. This study aimed to investigate immune imbalance and how the latter relates to clinical manifestations in patients with TRS. The level of net inflammation was estimated by evaluating the immune-inflammatory response system and compensatory immune-regulatory reflex system (IRS/CIRS) in 52 patients with TRS, 47 with non-TRS, and 56 sex and age matched healthy controls. The immune biomarkers mainly included macrophagic M1, T helper, Th-1, Th-2, Th-17, and T regulatory cytokines and receptors. Plasma cytokine levels were measured using enzyme-linked immunosorbent assay. Psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). Subcortical volumes were quantified using a 3-T Prisma Magnetic Resonance Imaging scanner. The results showed that (1) patients with TRS were characterized by activated pro-inflammatory cytokines and relatively insufficient anti-inflammatory cytokines, with an elevated IRS/CIRS ratio indicating a new homeostatic immune setpoint; (2) IRS/CIRS ratio was positively correlated with larger lateral ventricle volume and higher PANSS score in patients with TRS. Our findings highlighted the inflammatory disequilibrium as a potential pathophysiological process of TRS.

Increased prefrontal cortical cells positive for macrophage/microglial marker CD163 along blood vessels characterizes a neuropathology of neuroinflammatory schizophrenia

Transcript levels of cytokines and SERPINA3 have been used to define a substantial subset (40%) of individuals with schizophrenia with elevated inflammation and worse neuropathology in the dorsolateral prefrontal cortex (DLPFC). In this study, we tested if inflammatory proteins are likewise related to high and low inflammatory states in the human DLFPC in people with schizophrenia and controls. Levels of inflammatory cytokines (IL6, IL1β, IL18, IL8) and a macrophage marker (CD163 protein) were measured in brains obtained from the National Institute of Mental Health (NIMH) (N = 92). First, we tested for diagnostic differences in protein levels overall, then we determined the percentage of individuals that could be defined as "high" inflammation using protein levels. IL-18 was the only cytokine to show increased expression in schizophrenia compared to controls overall. Interestingly, two-step recursive clustering analysis showed that IL6, IL18, and CD163 protein levels could be used as predictors of "high and low" inflammatory subgroups. By this model, a significantly greater proportion of schizophrenia cases (18/32; 56.25%; SCZ) were identified as belonging to the high inflammatory (HI) subgroup compared to control cases (18/60; 30%; CTRL) [χ2(1) = 6.038, p = 0.014]. When comparing across inflammatory subgroups, IL6, IL1β, IL18, IL8, and CD163 protein levels were elevated in both SCZ-HI and CTRL-HI compared to both low inflammatory subgroups (all p < 0.05). Surprisingly, TNFα levels were significantly decreased (-32.2%) in schizophrenia compared to controls (p < 0.001), and were most diminished in the SCZ-HI subgroup compared to both CTRL-LI and CTRL-HI subgroups (p < 0.05). Next, we asked if the anatomical distribution and density of CD163+ macrophages differed in those with schizophrenia and high inflammation status. Macrophages were localized to perivascular sites and found surrounding small, medium and large blood vessels in both gray matter and white matter, with macrophage density highest at the pial surface in all schizophrenia cases examined. A higher density of CD163+ macrophages, that were also larger and more darkly stained, was found in the SCZ-HI subgroup (+154% p < 0.05). We also confirmed the rare existence of parenchymal CD163+ macrophages in both high inflammation subgroups (schizophrenia and controls). Brain CD163+ cell density around blood vessels positively correlated with CD163 protein levels. In conclusion, we find a link between elevated interleukin cytokine protein levels, decreased TNFα protein levels, and elevated CD163+ macrophage densities especially along small blood vessels in those with neuroinflammatory schizophrenia.

Correlation between elevated serum interleukin-1β, interleukin-16 levels and psychiatric symptoms in patients with schizophrenia at different stages

BACKGROUND

There is increasing evidence that immune dysfunction plays an important role in the pathogenesis of schizophrenia. Meso Scale Discovery (MSD) is bioanalytical method, which can detect serum inflammatory factors in patients. MSD has higher sensitivities, capturing a narrower range of proteins compared to other methods typically used in similar studies. The present study was aimed to explore the correlation between the levels of serum inflammatory factors and psychiatric symptoms in patients with schizophrenia at different stages and investigate a wide panel of inflammatory factors as independent factors for the pathogenesis of schizophrenia.

METHODS

We recruited 116 participants, including patients with first-episode schizophrenia (FEG, n = 40), recurrence patients (REG, n = 40) with relapse-episode schizophrenia, and a control group (healthy people, HP, n = 36). Patients are diagnosed according to the DSM -V. The plasma levels of IFN-γ, IL-10, IL-1β, IL-2, IL-6, TNF-α, CRP, VEGF, IL-15, and IL-16 were tested by the MSD technique. Patient-related data was collected, including sociodemographic data, positive and negative symptom scale (PANSS), and brief psychiatric rating scale (BPRS) and subscale scores. The independent sample T test, χ2 test, Analysis of covariance (ANCOVA), the least significant difference method (LSD), Spearman's correlation test, binary logistic regression analysis and ROC curve analysis were used in this study.

RESULTS

There were significant differences in serum IL-1β (F = 2.37, P = 0.014) and IL-16 (F = 4.40, P < 0.001) levels among the three groups. The level of serum IL-1β in the first-episode group was significantly higher than in the recurrence group (F = 0.87, P = 0.021) and control group (F = 2.03, P = 0.013), but there was no significant difference between the recurrence group and control group (F = 1.65, P = 0.806). The serum IL-16 levels in the first-episode group (F = 1.18, P < 0.001) and the recurrence group (F = 0.83, P < 0.001) were significantly higher than in the control group, and there was no significant difference between the first-episode group and the recurrence group (F = 1.65, P = 0.61). Serum IL-1β was negatively correlated with the general psychopathological score (GPS) of PANSS (R=-0.353, P = 0.026). In the recurrence group, serum IL-16 was positively correlated with the negative score (NEG) of the PANSS scale (R = 0.335, P = 0.035) and negatively correlated with the composite score (COM) (R=-0.329, P = 0.038). In the study, IL-16 levels were an independent variable of the onset of schizophrenia both in the first-episode (OR = 1.034, P = 0.002) and recurrence groups (OR = 1.049, P = 0.003). ROC curve analysis showed that the areas under IL-16(FEG) and IL-16(REG) curves were 0.883 (95%CI:0.794-0.942) and 0.887 (95%CI:0.801-0.950).

CONCLUSIONS

Serum IL-1β and IL-16 levels were different between patients with schizophrenia and healthy people. Serum IL-1β levels in first-episode schizophrenia and serum IL-16 levels in relapsing schizophrenia were correlated with the parts of psychiatric symptoms. The IL-16 level may be an independent factor associating with the onset of schizophrenia.

Induced pluripotent stem cell-derived astrocytes from patients with schizophrenia exhibit an inflammatory phenotype that affects vascularization

Molecular and functional abnormalities of astrocytes have been implicated in the etiology and pathogenesis of schizophrenia (SCZ). In this study, we examined the proteome, inflammatory responses, and secretome effects on vascularization of human induced pluripotent stem cell (hiPSC)-derived astrocytes from patients with SCZ. Proteomic analysis revealed alterations in proteins related to immune function and vascularization. Reduced expression of the nuclear factor kappa B (NF-κB) p65 subunit was observed in these astrocytes, with no incremental secretion of cytokines after tumor necrosis factor alpha (TNF-α) stimulation. Among inflammatory cytokines, secretion of interleukin (IL)-8 was particularly elevated in SCZ-patient-derived-astrocyte-conditioned medium (A_SCZCM). In a chicken chorioallantoic membrane (CAM) assay, A_SCZCM reduced the diameter of newly grown vessels. This effect could be mimicked with exogenous addition of IL-8. Taken together, our results suggest that SCZ astrocytes are immunologically dysfunctional and may consequently affect vascularization through secreted factors.

Decision tree distinguish affective disorder diagnosis from psychotic disorder diagnosis with clinical and lab factors

Background

Affective symptoms usually occur at the same time of psychotic symptoms. An effective predictive method would help the differential diagnosis at an early stage of the mental disorder. The purpose of the study was to establish a predictive model by using laboratory indexes and clinical factors to improve the diagnostic accuracy.

Methods

Subjects were patients diagnosed with psychiatric disorders with affective and/or psychotic symptoms. Two patient samples were collected in the study (n = 309) With three classification methods (logistic regression, decision tree, and discriminant analysis), we established the models and verified the models.

Results

Seven predictors were found to be significant to distinguish the affective disorder diagnosis from the psychotic disorder diagnosis in all three methods, the 7 factors were Activities of daily living, direct bilirubin, apolipoproteinA1, lactic dehydrogenase, creatinine, monocyte count and interleukin-8. The decision tree outperformed the other 2 methods in area under the receiver operating characteristic curve, and also had the highest percentage of correctly classification.

Conclusion

We established a predictive model that included activities of daily living, biochemical, and immune indicators. In addition, the model established by the decision tree method had the highest predictive power, which provided a reliable basis for future clinical work. Our work would help make diagnosis more accurate at an early stage of the disorder.

Elevated Serum Purine Levels in Schizophrenia: A Reverse Translational Study to Identify Novel Inflammatory Biomarkers

BACKGROUND

Immunological markers and related signaling molecules in the blood are altered in schizophrenia mouse models, in acutely relapsed patients with schizophrenia, and in persons at a clinically high risk for subsequently developing psychosis, highlighting their potential as prognostic and theranostic biomarkers. Therefore, we herein aimed to identify novel potential biomarkers in the serum that are associated with purinergic signaling.

METHODS

To our knowledge, this is the first study to assess the correlations among the levels of human serum adenine nucleotides (ATP, ADP), adenosine, P2X7 receptor, and disease activity in patients hospitalized due to an acute relapse of schizophrenia (n = 53) and healthy controls (n = 47). In addition, to validate these findings using a reverse translational approach, we examined the same parameters in an acute phencyclidine-induced schizophrenia mouse model.

RESULTS

We found consistently elevated levels of ATP, ADP, interleukin (IL)-6, and IL-10 in both schizophrenia groups compared with the controls. The levels of adenosine, IL-1β, IL-12, and C-reactive protein were also increased in the human patient samples. Moreover, ATP and ADP were significantly positively correlated with the Positive and Negative Symptom Scale item "lack of judgment and insight"; IL-1β, IL-12, and tumour necrosis factor alpha were significantly positively correlated with "tension" and "depression"; and "disorientation" and "poor attention" were correlated significantly with IL-6 and IL-8.

CONCLUSIONS

Our study suggests the promising potential of blood purines and inflammatory markers as future prognostic tools.

Demographic and Clinical Factors Related to Severe COVID-19 Infection and Mortality in Patients With Schizophrenia

We aimed to explore the prevalence and determinants of severe COVID-19 disease and mortality in patients with schizophrenia in this study. We conducted a retrospective observational study of 1620 patients with schizophrenia. Of the 1620 patients, 52 (3.2%) tested positive for SARS-CoV-19. Among SARS-CoV-2-positive patients, 40 patients were hospitalized, and 17 patients required intensive care unit admission due to COVID-19 (76.9% and 32.7%, respectively). Severe COVID-19 disease was noted in 17 patients (32.7%) requiring intubation. In the logistic regression analysis, antipsychotic dose, and comorbidity score were independently associated with a greater risk of severe COVID-19 disease in patients with schizophrenia. Our study suggests that factors such as age, sex, comorbidities, and a daily antipsychotic dose may have effects on the poor outcome of SARS-CoV-2 disease in schizophrenia patients. In addition, the current findings propose that mortality may be associated with an older age, comorbidity score, and a longer duration of psychiatric disease among the SARS-CoV-2-positive patients with schizophrenia. However, the findings of our study should be verified in prospective and larger sample studies.

Severe symptoms predict salivary interleukin-6, interleukin-1β, and tumor necrosis factor-α levels in children and youth with obsessive-compulsive disorder

OBJECTIVE

Childhood-onset obsessive-compulsive disorder (OCD) has been associated with immune dysregulation, including aberrant plasma inflammatory markers and increased rates of infectious and immune-mediated disorders. Saliva may provide a minimally-invasive tool for assessing oral mucosal immunity and inflammatory biomarkers in this population. The primary aim of this study was to compare salivary defense proteins and inflammatory mediators in saliva from children and youth with OCD and healthy controls, and evaluate their associations with measures of oral health and OCD phenotype.

METHODS

In this cross-sectional observational study, saliva was collected from 41 children and youth with childhood-onset OCD and 46 healthy controls. Levels of lysozyme, α-amylase, secretory immunoglobulin A (sIgA), C-reactive protein (CRP), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) were quantified by enzyme-linked immunosorbent assays or electrochemiluminescent-based immunoassays.

RESULTS

All analytes were detectable in saliva. When adjusting for salivary flow rate and total protein, multiple linear regression models including demographic variables, oral health measures, and OCD status explained a significant proportion of the variance in IL-6, IL-1β, and sIgA but not TNF-α, CRP, α-amylase, or lysozyme levels. Diagnosis of OCD was associated with significantly higher IL-6 (β = 0.403, p = 0.026), while severity of OCD was a significant predictor of increased cytokines (IL-6, β = 0.325, p = 0.009; IL-1β, β = 0.284, p = 0.020; TNF-α, β = 0.269, p = 0.036), but not other analytes.

CONCLUSION

These data point to the feasibility of analyzing soluble immune mediators in the saliva in childhood-onset OCD, suggesting that pro-inflammatory cytokines are associated with OCD diagnosis and symptom severity. Further work is required to elucidate the factors contributing to this association and implications for clinical practice.

Serum Levels and in vitro CX3CL1 (Fractalkine), CXCL8, and IL-10 Synthesis in Phytohemaglutinin-Stimulated and Non-stimulated Peripheral Blood Mononuclear Cells in Subjects With Schizophrenia

INTRODUCTION

Although schizophrenia is a severe mental illness, whose etiology is still largely unknown, its pathogenesis may be associated with dysregulation of the immune mechanisms. The present study compares the levels of interleukin (IL)-10, interleukin-8 (CXCL8), and fractalkine (CX3CL1) between schizophrenia patients and healthy controls. It also assesses the ability of peripheral peripheral blood mononuclear cells (PBMCs) to produce these cytokines spontaneously and following mitogen-stimulation.

MATERIALS AND METHODS

A prospective study was performed of 60 adult schizophrenia patients and 32 controls. CXCL8, IL-10, and fractalkine concentrations were measured in serum and supernatants from cultured PBMCs. Anthropometric (BMI, WHR) and body composition measurements were taken using bioimpedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA).

RESULTS AND CONCLUSION

The schizophrenia patients demonstrated significantly higher levels of serum CXCL8 (schizophrenia: 13.4 ± 15.7 pg/mL, control: 6.9 ± 4.2 pg/mL, p = 0.001) and lower level of serum fractalkine (schizophrenia: 22.8 ± 9.9 pg/mL, control: 45.4 ± 84.5 pg/mL, p = 0.041). Serum IL-10 levels did not significantly differ. No in vitro synthesis of fractalkine was observed. Neither unstimulated or PHA-stimulated CXCL8 secretion differed between the two groups (p >0.05). The patients not taking mood stabilizers (MS-) demonstrated significantly higher CXCL8 levels than those on mood stabilizers (MS+) (p = 0.03) and control (p < 0.001). In addition, the MS- sub-group demonstrated significantly lower serum fraktalkine than controls (p = 0.009). These effects could be described as pseudo-normalization of CXCL8 and fractalkine in schizophrenia patients taking mood stabilizers.

Integrative omics of schizophrenia: from genetic determinants to clinical classification and risk prediction

Schizophrenia (SCZ) is a debilitating neuropsychiatric disorder with high heritability and complex inheritance. In the past decade, successful identification of numerous susceptibility loci has provided useful insights into the molecular etiology of SCZ. However, applications of these findings to clinical classification and diagnosis, risk prediction, or intervention for SCZ have been limited, and elucidating the underlying genomic and molecular mechanisms of SCZ is still challenging. More recently, multiple Omics technologies - genomics, transcriptomics, epigenomics, proteomics, metabolomics, connectomics, and gut microbiomics - have all been applied to examine different aspects of SCZ pathogenesis. Integration of multi-Omics data has thus emerged as an approach to provide a more comprehensive view of biological complexity, which is vital to enable translation into assessments and interventions of clinical benefit to individuals with SCZ. In this review, we provide a broad survey of the single-omics studies of SCZ, summarize the advantages and challenges of different Omics technologies, and then focus on studies in which multiple omics data are integrated to unravel the complex pathophysiology of SCZ. We believe that integration of multi-Omics technologies would provide a roadmap to create a more comprehensive picture of interactions involved in the complex pathogenesis of SCZ, constitute a rich resource for elucidating the potential molecular mechanisms of the illness, and eventually improve clinical assessments and interventions of SCZ to address clinical translational questions from bench to bedside.

Pharmacotherapy of schizophrenia: immunological aspects and potential role of immunotherapy

INTRODUCTION

Schizophrenia is a complex disorder owing to diversity in clinical phenotypes, overlapping symptoms, and heterogeneous clinical presentation. Even after decades of research, the exact causative mechanisms of schizophrenia are not completely known. Recent evidence indicates the role of immune dysfunction in schizophrenia pathogenesis as observed from alteration in immune cells, increased activity of complement cascade, and development of autoantibodies against neurotransmitter receptors. Immunotherapy involving immunosuppressants and cytokine-targeting drugs, have shown promising results in several clinical studies and it demands further research in this area.

AREAS COVERED

Here, the authors review the immunopathogenesis of schizophrenia, limitations of conventional, and atypical antipsychotic drugs and the potential role and limitations of immunotherapeutic drugs in schizophrenia management.

EXPERT OPINION

Schizophrenia is a complex disorder and poses a challenge to the currently available treatment approaches. Nearly 30% schizophrenia patients exhibit minimal response toward conventional and atypical antipsychotic drugs. Immune system dysfunction plays an important part of schizophrenia pathophysiology and existing monoclonal antibody (mAb) drugs targeting specific components of the immune system are being repositioned in schizophrenia. The authors call upon public and private funders to facilitate urgent and rigorous research efforts in exploring potential role of immunotherapy in schizophrenia.

Plasma Levels of the Cytokines B Cell-Activating Factor (BAFF) and A Proliferation-Inducing Ligand (APRIL) in Schizophrenia, Bipolar, and Major Depressive Disorder: A Cross Sectional, Multisite Study

BACKGROUND

Immune dysfunction has been implicated in the pathogenesis of schizophrenia and other nonaffective psychosis (SCZ), bipolar spectrum disorder (BIP) and major depressive disorder (MDD). The cytokines B cell-activating factor (BAFF) and A proliferation-inducing ligand (APRIL) belong to the tumor necrosis factor (TNF) super family and are essential in orchestrating immune responses. Abnormal levels of BAFF and APRIL have been found in autoimmune diseases with CNS affection.

METHODS

We investigated if plasma levels of BAFF and APRIL differed between patients with SCZ, BIP, and MDD with psychotic symptoms (n = 2009) and healthy control subjects (HC, n = 1212), and tested for associations with psychotic symptom load, controlling for sociodemographic status, antipsychotic and other psychotropic medication, smoking, body-mass-index, and high sensitivity CRP.

RESULTS

Plasma APRIL level was significantly lower across all patient groups compared to HC (P < .001; Cohen's d = 0.33), and in SCZ compared to HC (P < .001; d = 0.28) and in BIP compared to HC (P < .001; d = 0.37). Lower plasma APRIL was associated with higher psychotic symptom load with nominal significance (P = .017), but not with any other clinical characteristics. Plasma BAFF was not significantly different across patient groups vs HC, but significantly higher in BIP compared to HC (P = .040; d = 0.12) and SCZ (P = .027; d = 0.10).

CONCLUSIONS

These results show aberrant levels of BAFF and APRIL and association with psychotic symptoms in patients with SCZ and BIP. This suggest that dysregulation of the TNF system, mediated by BAFF and APRIL, is involved in the pathophysiology of psychotic disorders.

The Role of Cytokines in the Pathogenesis of Schizophrenia

Schizophrenia is a chronic mental illness of unknown etiology. A growing and compelling body of evidence implicates immunologic dysfunction as the key element in its pathomechanism. Cytokines, whose altered levels have been increasingly reported in various patient populations, are the major mediators involved in the coordination of the immune system. The available literature reports both elevated levels of proinflammatory as well as reduced levels of anti-inflammatory cytokines, and their effects on clinical status and neuroimaging changes. There is evidence of at least a partial genetic basis for the association between cytokine alterations and schizophrenia. Two other factors implicated in its development include early childhood trauma and disturbances in the gut microbiome. Moreover, its various subtypes, characterized by individual symptom severity and course, such as deficit schizophrenia, seem to differ in terms of changes in peripheral cytokine levels. While the use of a systematic review methodology could be difficult due to the breadth and diversity of the issues covered in this review, the applied narrative approach allows for a more holistic presentation. The aim of this narrative review was to present up-to-date evidence on cytokine dysregulation in schizophrenia, its effect on the psychopathological presentation, and links with antipsychotic medication. We also attempted to summarize its postulated underpinnings, including early childhood trauma and gut microbiome disturbances, and propose trait and state markers of schizophrenia.

Classification of Psychoses Based on Immunological Features: A Machine Learning Study in a Large Cohort of First-Episode and Chronic Patients

For several years, the role of immune system in the pathophysiology of psychosis has been well-recognized, showing differences from the onset to chronic phases. Our study aims to implement a biomarker-based classification model suitable for the clinical management of psychotic patients. A machine learning algorithm was used to classify a cohort of 362 subjects, including 160 first-episode psychosis patients (FEP), 70 patients affected by chronic psychiatric disorders (schizophrenia, bipolar disorder, and major depressive disorder) with psychosis (CRO) and 132 health controls (HC), based on mRNA transcript levels of 56 immune genes. Models distinguished between FEP, CRO, and HC and between the subgroup of drug-free FEP and HC with a mean accuracy of 80.8% and 90.4%, respectively. Interestingly, by using the feature importance method, we identified some immune gene transcripts that contribute most to the classification accuracy, possibly giving new insights on the immunopathogenesis of psychosis. Therefore, our results suggest that our classification model has a high translational potential, which may pave the way for a personalized management of psychosis.

An observational study investigating cytokine levels in the cerebrospinal fluid of patients with schizophrenia spectrum disorders

INTRODUCTION

The role of immunological mechanisms in the pathophysiology of mental disorders has been discussed with increasing frequency. In this context, especially schizophrenia has become the focus of attention after the discovery of autoimmune encephalitis, which might present with psychotic symptoms. Furthermore, multiple studies have identified associations between infections or autoimmune diseases and schizophreniform disorders. Cerebrospinal fluid (CSF) analysis plays a central role in identifying potential inflammatory processes in the central nervous system. Therefore, the rationale of this retrospective study was the analysis of different cytokines, including interleukin-8 (IL-8) levels, in the CSF of patients with schizophrenia spectrum disorders.

METHODS

The authors examined the CSF of 40 patients with schizophrenia spectrum disorders, in comparison to the CSF of a mentally healthy control group of 39 patients with idiopathic intracranial hypertension (IIH). Magnetic bead multiplexing immunoassay was used to retrospectively determine different cytokines in the participants' CSF.

RESULTS

Participants with schizophrenia spectrum disorders had significantly higher IL-8 levels in their CSF than controls (mean ± SD: 41.83 ± 17.50 pg/ml versus 21.40 ± 7.96 pg/ml; p < 0.001).

CONCLUSION

The main finding of this study is the presence of significantly higher IL-8 concentrations in the CSF of patients with schizophrenia spectrum disorders when compared to the control group. This supports the hypothesis that immunological processes may be involved in the pathophysiology of a subgroup of patients with schizophrenia spectrum disorders. However, the study's results are limited by the retrospective design, methodological aspects, and the control group with IIH.

Roles of inflammation in intrinsic pathophysiology and antipsychotic drug-induced metabolic disturbances of schizophrenia

Schizophrenia is a debilitating psychiatric illness that remains poorly understood. While the bulk of symptomatology has classically been associated with disrupted brain functioning, accumulating evidence demonstrates that schizophrenia is characterized by systemic inflammation and disturbances in metabolism. Indeed, metabolic disease is a major determinant of the high mortality rate associated with schizophrenia. Antipsychotic drugs (APDs) have revolutionized management of psychosis, making it possible to rapidly control psychotic symptoms. This has ultimately reduced relapse rates of psychotic episodes and improved overall quality of life for people with schizophrenia. However, long-term APD use has also been associated with significant metabolic disturbances including weight gain, dysglycemia, and worsening of the underlying cardiometabolic disease intrinsic to schizophrenia. While the mechanisms for these intrinsic and medication-induced metabolic effects remain unclear, inflammation appears to play a key role. Here, we review the evidence for roles of inflammatory mechanisms in the disease features of schizophrenia and how these mechanisms interact with APD treatment. We also discuss the effects of common inflammatory mediators on metabolic disease. Then, we review the evidence of intrinsic and APD-mediated effects on systemic inflammation in schizophrenia. Finally, we speculate about possible treatment strategies. Developing an improved understanding of inflammatory processes in schizophrenia may therefore introduce new, more effective options for treating not only schizophrenia but also primary metabolic disorders.

Role of interleukin 8 in depression and other psychiatric disorders

Low grade neuroinflammation has been suggested as one of the underlying mechanisms of many psychiatric diseases as well as cognitive disorders. Interleukin 8 (IL-8), a proinflammatory cytokine produced by many cell types including macrophage and microglia, mainly functions as a neutrophil chemoattractant in the bloodstream. IL-8 is also found in the brain, where it is released from microglia in response to proinflammatory stimuli. In this review, we highlight studies focusing on the role of IL-8 in psychiatric diseases such as major depression, bipolar disorder, schizophrenia, sleep disorder, autism spectrum disorder, anxiety disorders and dementia. Increased peripheral IL-8 levels have been reported in these diseases, particularly in schizophrenic disorder, bipolar disorder, obstructive sleep apnea and autism spectrum disorder. The literature on IL-8 and major depression is inconsistent. IL-8 has been found to be a factor associated with schizophrenic prognosis and therapeutic response, and may affect a wide range of symptomatology. Considering that the exact role of immune alterations is still under research, the success of immune-based therapies in psychiatric diseases is limited for the time being.

Schizophrenia: Complement Cleaning or Killing

Schizophrenia is a psychiatric disorder with a typical onset occurring during adolescence or young adulthood. The heterogeneity of the disorder complicates our understanding of the pathophysiology. Reduced cortical synaptic densities are commonly observed in schizophrenia and suggest a role for excessive synaptic elimination. A major pathway hypothesised to eliminate synapses during postnatal development is the complement system. This review provides an overview of genetic and functional evidence found for the individual players of the classical complement pathway. In addition, the consequences of the absence of complement proteins, in the form of complement protein deficiencies in humans, are taken into consideration. The collective data provide strong evidence for excessive pruning by the classical complement pathway, contributing to cognitive impairment in schizophrenia. In future studies, it will be important to assess the magnitude of the contribution of complement overactivity to the occurrence and prevalence of phenotypic features in schizophrenia. In addition, more insight is required for the exact mechanisms by which the complement system causes excessive pruning, such as the suggested involvement of microglial engulfment and degradation of synapses. Ultimately, this knowledge is a prerequisite for the development of therapeutic interventions for selective groups of schizophrenia patients.

Resveratrol inhibits MRGPRX2-mediated mast cell activation via Nrf2 pathway

Mast cells (MCs) are crucial effectors in inflammation and allergic reactions. The Mas-related G-protein-coupled receptor X2 (MRGPRX2) was the MC-specific receptor and play a key role in IgE-independent allergic reactions. The activation of the Nuclear factor erythroid derived 2-related factor 2 (Nrf2) is involved in IgE-mediated MC degranulation. Resveratrol (Res) is a polyphenolic compound in red wine and has been reported to exert a variety of pharmacological effects. In the current study, we investigated the effect of Res in regulating MRGPRX2-mediated MC activation and its underlyingmechanism. We demonstrated that Res reduced compound 48/80 (C48/80)-induced calcium flux in MCs and inhibited MCs degranulation in vitro. Res also suppressed C48/80-induced hind paw extravasation, active systemic anaphylaxis, and MCs degranulation in mouse models of pseudo-allergy in vivo. Furthermore, PCR and immunohistochemistry assay suggest that Res up-regulates Nrf2 expression and Nrf2 inhibitor attenuates the protective effects of Res. In conclusion, Res exerts an inhibitory effect on MRGPRX2-mediated MCs activation by targeting Nrf2 pathway and may present a promising new therapeutic agent for the treatment of MRGPRX2-dependent anaphylactoid reactions.

Changes in inflammation are related to depression and amount of aerobic exercise in first episode schizophrenia

INTRODUCTION

Elevated levels of pro-inflammatory cytokines have been reported in meta-analyses of multi-episode schizophrenia patients when compared to controls. However, little is known about whether these same relationships are present in the early course of schizophrenia.

OBJECTIVE

To assess first episode schizophrenia patients for depression and to assay blood samples collected at baseline and at 6 months for interleukin-6 (IL-6).

MATERIALS AND METHODS

Trained raters used the Brief Psychiatric Rating Scale to assess depressive symptoms and a standard lab assay kit to assess for IL-6 levels in plasma.

CONCLUSIONS

Decreases in pro-inflammatory IL-6 levels were significantly related to decreases in depressive symptoms. Within a subset of patients in a 6-month aerobic exercise protocol, the number of exercise sessions completed was significantly correlated with the amount of decrease in IL-6. The reductions observed in IL-6 with aerobic exercise suggest exercise is a promising intervention to reduce brain inflammation effects in schizophrenia patients.

Serum interleukin-6 in schizophrenia: A system review and meta-analysis

BACKGROUND

Schizophrenia is a disabling serious mental illness with unknown etiology. Inflammatory abnormalities play an important role in the pathogenesis of the disease. Many studies had viewed changes in serum IL-6 in schizophrenia, but its results were not consistent. This meta-analysis was to systematically assess the changes in serum IL-6 in schizophrenia.

METHODS

We searched PubMed, Web of Science, ScienceDirect, and EBSCO databases until July 14, 2020, for eligible studies that matched to search subjects, and used Review Manager to counting all the research results.

RESULTS

The meta-analysis included 14 studies comprising 961 schizophrenia and 729 controls. Serum IL-6 was higher in schizophrenia compared with controls (SMD: 0.44 [95%CI: 0.34-0.55] for drug naïve or drug eluted schizophrenia; SMD: 1.55 [95%CI: 0.78-2.31] for schizophrenia after treatment). Serum IL-6 of schizophrenia after treatment was lower than baseline (SMD: 0.33 [95%CI: 0.02-0.63]).

CONCLUSIONS

Serum IL-6 level increase in schizophrenia. It supports the immune regulatory system-compensatory immune regulatory system hypothesis, and the role of inflammatory abnormalities in schizophrenia. And the decrease of serum IL-6 in schizophrenia after treatment suggests that an anti-inflammatory mechanism might be effective during antipsychotic treatment.

Elevated environmental PM2.5 increases risk of schizophrenia relapse: Mediation of inflammatory cytokines

BACKGROUND

Ecological epidemiology suggests that hospital admissions for schizophrenia are associated with an increased environmental PM_2.5, but no prospective study has verified this result, and the physiological mechanism is not clear.

METHODS

We used a repeated-measures design to prospectively assess the association of environmental PM_2.5 and the risk of relapse in schizophrenia, and used two linear mixed-effects models to explore possible mediating effects of immune cytokines on the premise of controlling confounders.

RESULTS

We import the data using EpiData software, and collate and analyze of the data using R software. The increase of PM_2.5 at lag0 had the greatest impact on the relapse of schizophrenia (for each 10 μg/m³ increase in PM_2.5, the relapse risk score increased by 1.504, that is to say, odds ratio (OR) = 4.500 (95% confidence interval (CI): 2.849-7.106，P < 0.001)), and cumulative effects lasted for four days with the maximum at the second day (for each 10 μg/m³ increase in PM_2.5, the relapse risk score increased by 1.301, OR = 3.673 (95%CI: 1.962-6.876，P < 0.001)). PM_2.5 exposure was statistically related to four symptom dimensions of early signs scale (ESS), and the symptoms most affected by the increased PM_2.5 were depression/withdrawal (ESSN) (OR = 1.990, 95%CI: 1.701-2.328), anxiety/agitation (ESS-A) (OR = 1.537, 95%CI: 1.340-1.763), initial psychosis (ESS-IP) (OR = 1.398, 95%CI: 1.151-1.697), and disinhibition (ESS-D) (OR = 1.235, 95%CI: 1.133-1.347). Furthermore, there are three statistically significant pathways in intermediary analysis: of PM_2.5 and relapse risk: "PM_2.5 → IL-17 → ESS", "PM_2.5 → IL-17 → ESS-A", and "PM_2.5 → IL-17 → ESS-N", and the intermediary ratio of IL-17 was 11.66%, 16.37% and 22.55%, respectively.

CONCLUSIONS

Increased environmental PM_2.5 is a risk factor for the relapse of schizophrenia. Early relapse identification and intervention based on clinical characteristics are of great significance for timely termination of relapse and slowing down of relapse.

Cannabinoid use in psychotic patients impacts inflammatory levels and their association with psychosis severity

Inflammatory abnormalities are well-documented in individuals with chronic psychotic disorders. Particular attention has focused on interleukin-6 (IL-6) and its correlation with psychotic symptom severity. Cannabis use is associated with an increased risk of psychosis and also has immunomodulating properties. It has been hypothesized that inflammatory disturbances are a common underlying pathology between cannabis use and psychosis. We measured inflammatory markers in individuals admitted to a psychiatric unit with acute psychosis who had toxicology positive for natural and/or synthetic cannabinoids (n = 59) compared to patients with negative cannabinoid toxicology (n = 60). Psychosis severity was assessed using the Positive and Negative Syndrome Scale (PANSS). While PANSS scores were similar between groups, cannabinoid-positive participants were more likely to receive pro re nata (PRN or as-needed) medications for agitation in the psychiatric emergency room, particularly synthetic cannabinoid-positive participants. In unadjusted models, cannabinoid-positive participants had lower interferon-γ (IFN-γ) levels (p = 0.046), but this finding was not significant after adjusting for covariates and multiple comparisons. Among cannabinoid-positive participants, IL-6 levels negatively correlated with PANSS total score (p = 0.040), as well as positive (p = 0.035) and negative (p = 0.024) subscales. Results suggest inflammatory alterations among psychotic individuals with comorbid cannabinoid use.

Longitudinal study of inflammatory markers and psychopathology in schizophrenia

OBJECTIVE

Schizophrenia is associated with abnormal levels of blood inflammatory markers, which may be correlated with levels of psychopathology. Few previous studies have explored whether baseline inflammatory marker levels predict longitudinal changes in psychopathology. In the present study, we explored this association in a cohort of patients with schizophrenia.

METHOD

We investigated inflammatory markers and psychopathology after 3, 6, and 12 months of antipsychotic treatment for subjects with baseline and follow-up data from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia trial. Linear regression models, controlling for multiple potential confounding factors, were used to investigate these associations.

RESULTS

There was a significant decrease in monocyte, ICAM, and adiponectin levels between baseline and 12 months. Higher baseline blood interleukin-6 (IL-6) predicted greater reduction in PANSS total and general subscale scores at 3 and 6 months, and PANSS negative subscale scores at 3 months (β = -0.10 to -0.16, p < 0.05 for each). Higher baseline blood leptin levels predicted greater reduction in PANSS total, negative and general subscale scores at 6 months (β = -0.09 to -0.11, p < 0.05 for each). In post-hoc analyses, associations between baseline IL-6 levels and symptom reduction were strongest in patients treated with either ziprasidone or quetiapine. Changes in blood inflammatory markers were generally not associated with changes in psychopathology.

CONCLUSIONS

Our findings provide additional support that measuring blood inflammatory markers may be relevant to the clinical care of patients with schizophrenia. Specifically, these markers may help guide selection of antipsychotic treatment towards more personalized medicine approaches for patients with schizophrenia.

Prednisolone versus placebo addition in the treatment of patients with recent-onset psychotic disorder: a trial design

BACKGROUND

The symptom severity of a substantial group of schizophrenia patients (30-40%) does not improve through pharmacotherapy with antipsychotic medication, indicating a clear need for new treatment options to improve schizophrenia outcome. Meta-analyses, genetic studies, randomized controlled trials, and post-mortem studies suggest that immune dysregulation plays a role in the pathophysiology of schizophrenia. Some anti-inflammatory drugs have shown beneficial effects on the symptom severity of schizophrenia patients. Corticosteroids are effective in various chronic inflammatory and autoimmune disorders. Prednisolone, a potent glucocorticosteroid, has minor mineral-corticosteroid potencies and can adequately pass the blood-brain barrier and its side effects and safety profile are well known. Therefore, the effect of prednisolone can be studied as a proof of concept for immune modulation as a treatment for schizophrenia.

METHODS/DESIGN

In total, 90 subjects aged 18-70 years and diagnosed with schizophrenia, schizoaffective disorder, or schizophreniform disorder (Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) 295.x) or psychosis not otherwise specified (NOS; 298.9) will be included. The time interval between the onset of psychosis and study entry should not exceed 7 years. Patients will be randomized 1:1 to either prednisolone or placebo daily for a period of 6 weeks in addition to a stable dose of antipsychotic medication. Study medication will be initiated at 40 mg for 3 days, after which it will be tapered down within 6 weeks after initiation, following inflammatory bowel diseases treatment guidelines. Primary outcome is change in symptom severity, expressed as change in total score on the Positive and Negative Symptom Scale (PANSS) from baseline to end of treatment. Cognitive functioning (measured through the Brief Assessment of Cognition in Schizophrenia (BACS)) and change in Global Assessment Functioning (GAF) and depressive symptoms as measured with the Calgary Depression Scale for Schizophrenia (CDS) will be assessed, in addition to various immunological biomarkers. Secondary outcomes are a 4- and 6-month follow-up assessment of PANSS, BACS, and GAF scores and immunological biomarkers. Additionally, a subgroup of patients will be included in the magnetic resonance imaging (MRI) part of the study where MR spectroscopy and structural, functional, and diffusion MRI will be conducted.

DISCUSSION

It is expected that prednisolone addition to current antipsychotic medication use will reduce symptom severity and will improve cognition when compared to placebo.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02949232 and NCT03340909. Registered 31 October 2016 and 14 November 2017. EudraCT-number 2014-000520-14 and 2017-000163-32.

Immunoneuropsychiatry - novel perspectives on brain disorders

Immune processes have a vital role in CNS homeostasis, resilience and brain reserve. Our cognitive and social abilities rely on a highly sensitive and fine-tuned equilibrium of immune responses that involve both innate and adaptive immunity. Autoimmunity, chronic inflammation, infection and psychosocial stress can tip the scales towards disruption of higher-order networks. However, not only classical neuroinflammatory diseases, such as multiple sclerosis and autoimmune encephalitis, are caused by immune dysregulation that affects CNS function. Recent insight indicates that similar processes are involved in psychiatric diseases such as schizophrenia, autism spectrum disorder, bipolar disorder and depression. Pathways that are common to these disorders include microglial activation, pro-inflammatory cytokines, molecular mimicry, anti-neuronal autoantibodies, self-reactive T cells and disturbance of the blood-brain barrier. These discoveries challenge our traditional classification of neurological and psychiatric diseases. New clinical paths are required to identify subgroups of neuropsychiatric disorders that are phenotypically distinct but pathogenically related and to pave the way for mechanism-based immune treatments. Combined expertise from neurologists and psychiatrists will foster translation of these paths into clinical practice. The aim of this Review is to highlight outstanding findings that have transformed our understanding of neuropsychiatric diseases and to suggest new diagnostic and therapeutic criteria for the emerging field of immunoneuropsychiatry.

The Role of Cytokines in Predicting the Efficacy of Acute Stage Treatment in Patients with Schizophrenia

PURPOSE

Inflammatory response in schizophrenia (SCz) is related to its underlying pathological mechanism and might be significant in deciding a patient's prognosis. The current study aims to investigate the differences in the serum inflammation level between schizophrenic patients and healthy controls and identify inflammatory markers that can predict clinical therapeutic effects in early-stage SCz patients at the 6-month follow-up.

PATIENTS AND METHODS

In total, 71 subjects were recruited in this study, including 35 patients with Scz and 36 healthy controls. The 35 Scz patients, who were in the first-episode or acute relapse state at admission, had completed the 6-month follow-up. The Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression (CGI) assessment results, demographic details, and blood samples were collected at the baseline and at follow-up. Data were analyzed using the Spearman correlation and multiple linear regression.

RESULTS

Serum interleukin (IL-1β, IL-4, IL-6, and IL-8) levels were significantly elevated in SCz patients at baseline compared with healthy controls, with a reduced IL-8 level at the follow-up. Furthermore, a higher IL-6 level and lower IL-8 level was found to predict better improvement in negative symptoms. The higher IL-6 level also predicted lesser improvement in depressive symptoms. Finally, a higher interferon (IFN)-γ level predicted a lower therapeutic effect for excitatory symptoms.

CONCLUSION

The serum levels of inflammatory markers were higher in patients with SCz than in healthy controls. These markers can be considered accurate predictors of therapeutic effects in patients with SCz.

The Relationship Between Serum Cytokine Levels and the Degree of Psychosis and Cognitive Impairment in Patients With Methamphetamine-Associated Psychosis in Chinese Patients

Background: Cytokine levels can be changed in methamphetamine (METH) use disorders (MUDs) and primary psychosis. The present study assessed serum levels of some kinds of interleukins (ILs) in METH-associated psychosis (MAP) and their relationships with psychotic symptoms and cognitive dysfunction. Methods: Serum IL-2R, IL-6, IL-8, and IL-10 levels were examined by chemiluminescence assays in MAP patients (n = 119) and healthy controls (n = 108). The Positive and Negative Syndrome Scale (PANSS) and Montreal Cognitive Assessment (MOCA) were administered. Results: Serum levels of IL-6 and IL-8 were significantly increased in MAP patients (all p < 0.05). There was a negative relationship between IL-2R levels and PANSS positive (P) subscale scores (r = -0.193, p = 0.035). IL-6, IL-8 and IL-10 levels were all negatively correlated with the naming, delayed recall and orientation subscores on the MOCA (r = -0.209, p = 0.022; r = -0.245, p = 0.007; r = -0.505, p < 0.001, respectively). Conclusions: Our results indicate that immune disturbances are related to MAP and that IL-2R, IL-6, IL-8, and IL-10 are associated with the severity of psychotic symptoms and cognitive function impairment.

Cytokine Alterations in Schizophrenia: An Updated Review

Schizophrenia, a multisystem disorder with an unknown etiology, is associated with several immune dysfunctions, including abnormal levels of circulating cytokines. In this review, we investigated the changes of cytokines in schizophrenic patients, their connection with behavioral symptoms severity and their potential clinical implications. We also assessed the possible causative role of abnormal cytokine levels in schizophrenia pathogenesis. Based on meta-analyses, we categorized cytokines according to their changes in schizophrenic patients into four groups: (1) increased cytokines, including interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β, IL-12, and transforming growth factor (TGF)-β, (2) non-altered cytokines, including IL-2, IL-4, and IL-17, (3) increased or non-altered cytokines, including IL-8 and interferon (IFN)-γ, and (4) IL-10 with increased, decreased, and non-altered levels. Notably, alterations in cytokines may be variable in four different categories of SP, including first-episode and drug-naïve, first-episode and non-drug-naïve, stable chronic, and chronic in acute relapse. Furthermore, disease duration, symptoms severity, incidence of aggression, and cognitive abilities are correlated with levels of certain cytokines. Clinical implications of investigating the levels of cytokine in schizophrenic patients include early diagnosis, novel therapeutic targets development, patient stratification for choosing the best therapeutic protocol, and predicting the prognosis and treatment response. The levels of IL-6, IL-8, IFN-γ, IL-2 are related to the treatment response. The available evidence shows a potential causative role for cytokines in schizophrenia development. There is a substantial need for studies investigating the levels of cytokines before disease development and delineating the therapeutic implications of the disrupted cytokine levels in schizophrenia.

Cytokines in agitated and non-agitated patients admitted to an acute psychiatric department: A cross-sectional study

BACKGROUND

Different psychiatric diagnostic groups have been reported to have cytokine levels deviating from healthy controls. In acute clinical settings however, the specific challenging symptoms and signs are more important than a diagnostic group. Thus, exploration of cytokines and immune activity and their role in specific symptoms is important. Reports in this field so far are sparse.

OBJECTIVE

In the present study, we aimed to examine the association between immune activity measured as levels of cytokines and agitation (independent of diagnostic group) in patients admitted to an acute psychiatric inpatient department.

METHODS

A total of 316 patients admitted to an acute psychiatric inpatient department were included. Thirty-nine patients with psychosis were subject to subgroup analyses. Agitation was assessed by the Positive and Negative Syndrome Scale, Excitement Component (PANSS-EC). Based on PANNS-EC patients were stratified into two groups: 67 agitated patients and 249 non-agitated patients. Serum concentrations of the following immune markers were measured: interleukin (IL) -1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF) -α, interferon (IFN) -γ and transforming growth factor (TGF) -β.

RESULTS

Serum levels of TNF-α were significantly higher in patients with agitation compared to those without, both when all patients were included in the analyses (p = 0.004) and in the psychosis group (p = 0.027). After correcting for multiple testing, only the findings in the total population remained significant.

CONCLUSIONS

Our findings suggest an association between TNF-α and agitation in an acute psychiatric population. A similar trend was reproduced to the psychosis subgroup. This suggests that agitation might be an independent entity associated with cytokines across different diagnostic groups.

Neuroinflammation and Schizophrenia

PURPOSE OF REVIEW

There are longstanding, intriguing findings of immune dysfunction in schizophrenia. These findings span peripheral immune markers, especially cytokine abnormalities.

RECENT FINDINGS

This review describes recent genetic and immune marker studies and emergent treatment studies. Collectively, this provides a synthesis and current appraisal of the neuroimmune hypothesis of schizophrenia.