Schizophrenia is a chronic severe mental disorder in which immunologic imbalances have been reported. Some researchers have demonstrated dysregulation of cytokine levels in this mental disorder. Considering the possible role of cytokines in the pathogenesis or clinical course of schizophrenia, we assessed serum levels of IL-4, IL-10, IL-17A and IFN-γ in a homogenous sample of Iranian patients who were in remission under treatment with Clozapine compared with sex and age matched controls. There was a statistically significant difference in IL-4 levels between patients and healthy subjects (P= 0.023). IL-4 levels were 83% higher in cases than in control group. No significant group*gender interaction was detected suggesting the similar IL-4 levels between males and females in each study group. There was no statistically significant difference in IFN-γ levels between patients and healthy subjects, but IFN-γ levels were 70% higher in male compared with female group. No significant differences have been found in serum levels of other cytokines between cases and controls or between males and females. The higher levels of IL-4 in patients treated with Clozapine might be due to effects of this antipsychotic drug on immune responses. Future studies are needed to elaborate the exact underlying mechanism.
Keywords: IFN-γ; IL-10; IL-17A; IL-4; Schizophrenia.