In vitro cytokine synthesis in unstimulated and mitogen-stimulated peripheral blood mononuclear cells from individuals with schizophrenia

Increasing evidence has shown that the immune system is involved in the schizophrenia development, with alterations in immune cell reactivity being one possible factor contributing to its pathogenesis. The purpose of the study was to evaluate in vitro the capability of peripheral blood mononuclear cells (PBMCs) obtained from subjects with schizophrenia and controls to engage in spontaneous and phytohemagglutinin (PHA)-stimulated cytokine production. The concentrations of various cytokines (interleukin (IL)-1β, IL-17A, tumor necrosis factor (TNF), interferon (IFN)-γ and IL-10) in supernatants from cultured PBMCs were measured using the cytometric bead array. No significant differences in the spontaneous production of IL-1β, IL-17A, IFN-γ and IL-10 by PBMCs were detected between individuals with schizophrenia and controls. TNF synthesis by PBMCs was found to be lower among those with schizophrenia. In all subjects and controls, greater cytokine generation was associated with PBMCs treated with PHA compared with those that were not. The PBMCs from people with schizophrenia displayed considerably higher sensitivity to mitogen stimulation, as the production of IL-17A, TNF and IFN-γ was at least threefold of that observed in healthy subjects, which may be driven by antipsychotics taken by patients with schizophrenia. Correlation was observed between spontaneous production of IFN-γ and Positive and Negative Syndrome Scale G subscore (which measures the general symptoms of schizophrenia) and between PHA-stimulated synthesis of IL–17A and G subscore. Our data confirm that the immune system dysregulation may underlie schizophrenia pathophysiology. There is a potential possibility that immunological tests could be used as a diagnostic, therapeutic and side-effects biomarker for schizophrenia, but further studies are needed.