Schizophrenia is accompanied with central nervous system and peripheral immune system imbalances. Interleukin-17 (IL-17) is implicated in various immune and inflammatory processes. Aberrant levels of IL-17 have been reported in patients with schizophrenia, whereas the results are not consistent. To clarify the relationship between IL-17 and schizophrenia, we performed a meta-analysis in this study. We carried out a structured literature search in PubMed and Embase database up to April 16, 2017, and retrieved all eligible case-control studies according to the inclusion criteria. Finally, a total of 313 patients with drug-naïve first-episode psychosis and 238 healthy control subjects from 5 studies were included in our meta-analysis. There were no significant differences between first-episode psychosis patients and healthy controls with respect to the levels of IL-17 (p = 0.21), even when we removed 2 studies which were not European samples (p = 0.12). Our findings suggested that IL-17 may not be involved in the pathological mechanism of schizophrenia.
Keywords: Drug-naïve patients; First-episode psychosis; Immune system; Inflammatory processes; Interleukin-17; Schizophrenia.