Elevated levels of C-reactive protein and IL-6 among the antipsychotic medicating schizophrenia patients of Siliguri, West Bengal, India

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.

Could CRP be a differential biomarker of illness stages in schizophrenia? A systematic review and meta-analysis

BACKGROUND

Patients with schizophrenia display peripheral inflammation but the impact of illness phase is not clear. Our meta-analysis investigated the difference in CRP levels between patients with schizophrenia and controls according to their illness phase.

METHODS

After a systematic search, all studies measuring CRP in patients with schizophrenia and controls were included. Standardized mean differences were calculated between patients and controls according to illness phase. The influence of sociodemographic and clinical variables on our results was investigated using a meta-regression analysis.

RESULTS

Fifty studies were included in this meta-analysis. Patients with schizophrenia had higher CRP levels than controls in the acute (p < 0.00001) and stable (p < 0.00001) stage of their disease. Patients with acute exacerbation of schizophrenia had higher CRP levels than stable patients (p = 0.02) but this difference did not persist when considering antipsychotic-medicated patients in both phases. Meta-regressions found that the increase of CRP in acutely ill patients as compared to controls was influenced by age (p < 0.01), BMI (p = 0.01) and first episode (p = 0.02), whereas the increase in CRP levels of stable patients as compared to controls was moderated by BMI (p = 0.004).

CONCLUSIONS

In conclusion, this meta-analysis provides strong evidence that patients with schizophrenia have higher CRP levels than controls, but also show an increase in inflammatory response in the acute stage of the disease as compared to the stable stage. CRP could thus be considered as a state marker and a trait marker of the disease.

Association between C-reactive protein levels and antipsychotic treatment during 12 months follow-up period after acute psychosis

BACKGROUND

A potential role of inflammatory pathways in the pathology of schizophrenia has been suggested for at least a subgroup of patients. Elevated levels of the inflammatory marker C-reactive protein (CRP) have been observed, with associations to pathogenesis and symptoms. The current evidence regarding effects of antipsychotics on CRP levels is ambiguous.

OBJECTIVES

To examine and compare the influence on CRP levels of three pharmacologically diverse new generation antipsychotics during a one-year follow-up in schizophrenia spectrum disorder.

METHODS

In a multicenter, pragmatic and rater-blinded randomized trial, the effects of amisulpride, aripiprazole and olanzapine were compared in 128 patients with schizophrenia spectrum disorder. All had positive symptoms of psychosis at study entry. Clinical and laboratory assessments including the measurement of CRP levels were conducted at baseline, and 1, 3, 6, 12, 26, 39, and 52 weeks thereafter.

RESULTS

For all antipsychotic drugs analysed together, there was an increase in CRP levels during the one-year follow-up. Aripiprazole, as opposed to amisulpride and olanzapine, was associated with a reduced CRP level after one week, after which the CRP level caught up with the other drugs. Compared to those previously exposed to antipsychotic drugs, antipsychotic-naïve patients had lower CRP levels at all follow-up time points, but with the same temporal patterns of change.

CONCLUSION

Treatment with amisulpride, aripiprazole and olanzapine showed different effects on CRP levels in patients with schizophrenia spectrum disorders, modified by previous antipsychotics exposure status. This finding suggests that antipsychotic drugs may vary with respect to their influence on pro-inflammatory pathways.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT01446328; URL: http://www.

CLINICALTRIALS

gov/.

Relationship Between Curative Effect and Serum Inflammatory Factors Level in Male Patients With First-Episode Schizophrenia Treated With Olanzapine

Background: A growing body of evidence shows that immune system disorders are one of the important etiological factors of schizophrenia. Inflammatory cytokines play a very critical role in the pathogenesis and treatment of schizophrenia. However, in the actual clinical practice, there is still a lack of confirmed biological indicators that can be used to evaluate the therapeutic effect of antipsychotics. Methods: In this study, 82 male patients with first-episode schizophrenia and 30 healthy controls were included. The Positive and Negative Syndrome Scale (PANSS) scores were evaluated, and the serum levels of high-sensitivity C-reactive protein (hs-CRP), interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 17 (IL-17), and transforming growth factor β1 (TGF-β1) were detected, both at baseline and 4 weeks later. The patients were divided into two groups, the effective group and the ineffective group, according to the reduction rate of PANSS. Results: In the case group, the levels of hs-CRP were significantly elevated (p = 0.00), whereas IL-1β, IL-6, and IL-17 were significantly reduced as compared to the baseline (p = 0.01, 0.02, and 0.00, respectively). Importantly, the baseline levels of the five inflammatory factors were significantly higher in the case group as compared to the control group (p = 0.00, 0.00, 0.00, 0.00, and 0.00, respectively). Post-treatment, the serum levels for IL-1β, IL-6, and IL-17 were significantly higher in the effective group than in the ineffective group (p = 0.00, 0.00, and 0.01, respectively). For every increase in the amount of IL-1β, the risk of ineffectiveness increased by 7% (OR = 0.93 [0.86-1.00]; p = 0.04), whereas for every increase in the amount of IL-17, the risk of ineffectiveness increased by 5% (OR = 0.95 [0.90-0.99]; p = 0.03). Conclusion: The results of the study showed that the levels of inflammatory factors in patients with different therapeutic effects were different, and the changes in the amounts of IL-1β and IL-17 acted as predictors of poor efficacy.

Monocyte count in schizophrenia and related disorders: a systematic review and meta-analysis

OBJECTIVE

Increasing evidence suggests that immunological and inflammatory dysfunctions may play an important role in predisposition, onset, and progression of schizophrenia and related psychosis. The activation of cells of the mononuclear phagocyte system, especially microglia and monocytes, has been reported in schizophrenia. We carried out this systematic review and meta-analysis to investigate if there are significant differences in monocyte count comparing healthy controls with people suffering from schizophrenia and related disorders.

METHODS

We searched main electronic databases; nine records met all our criteria and were included in the meta-analysis. Meta-analyses based on random effects models have been carried out generating pooled standardised mean differences (SMDs) of monocyte count in peripheral blood between schizophrenia and related psychosis and healthy controls. Heterogeneity was estimated. Relevant sensitivity and subgroup analyses were conducted.

RESULTS

Patients showed higher monocyte count as compared with healthy control (SMD = 0.393; p = 0.001). Heterogeneity across studies was from moderate to high (I2 = 65.952%); sensitivity analysis leaving out two studies responsible for most of the heterogeneity showed a slightly higher SMD. Subgroup analyses confirmed this result, showing no significant differences in the effect size across different study characteristics.

CONCLUSIONS

Monocyte count can be considered an indirect marker of microglia activation in the central nervous system. Thus, the observed higher monocyte count in patients could be considered as a possible peripheral marker of microglia's activation in schizophrenia disorder.

The association of cognitive performance and IL-6 levels in schizophrenia is influenced by age and antipsychotic treatment

Aims: Recent findings suggest that cognitive impairment can be associated with inflammation and immune changes in schizophrenia. We aimed to study possible associations between cytokine levels and cognitive performance in a sample of patients with schizophrenia.Methods: Cognition was assessed with the brief assessment of cognition in schizophrenia in 63 clinically stable outpatients with schizophrenia. Blood was collected and cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, TNF-α, IFN-γ) were measured by cytometric bead array method. Psychopathological scales were also applied.Results: IL-6 correlated negatively with general cognitive performance (rho = -0.395, p = .017) and positively with antipsychotic dose (rho = 0.412, p = .004). Multiple regression analysis showed that cognitive performance is associated with age and antipsychotic dose (p = .000 and p = .033).Conclusion: The association between IL-6 levels and cognitive performance is dependent on age and antipsychotic dose.

Immunomodulatory Effects of Antipsychotic Drugs in Whole Blood Cell Cultures from Healthy Subjects

Objective:

We aimed to evaluate the effects of various antipsychotics on the in vitro production of C-reactive protein (CRP) in whole blood cell cultures from healthy volunteers. The evaluation was performed using haloperidol, quetiapine, clozapine, amisulpride, and chlorpromazine.

Methods:

Antipsychotic agents were added to the participants' whole blood samples, and the resulting CRP levels were measured. For each agent, three different concentrations were tested: the therapeutic concentration, one-tenth the therapeutic concentration, and ten times the therapeutic concentration. The differences in CRP concentrations before and after drug administration were investigated.

Results:

The Friedman test showed that haloperidol, amisulpride, and chlorpromazine significantly increased CRP levels in the blood culture samples; however, clozapine and quetiapine did not increase CRP levels. In the case of chlorpromazine, elevated CRP levels were noted at all concentrations tested.

Conclusion:

Our study suggests that some antipsychotics elevate CRP levels in vitro. These results agree with previous studies showing that antipsychotics have immunomodulatory effects. Future research will clarify our findings and our understanding of antipsychotic drugs and their impact on immune regulation.