Increased Interleukin-17 and decreased BAFF serum levels in drug-free acute schizophrenia

• Compared to healthy controls, drug-free schizophrenic patients in acute phase of the disease exhibited significantly higher IL-17 and lower BAFF serum levels.
• No significant difference was found between patients and controls regarding IFN-γ serum levels. IL-4 was not detected in both groups.
• IL-17 and BAFF levels were negatively correlated in schizophrenic patients.
• SANS global score was negatively correlated with IL-17 and positively correlated with IFN-γ serum levels.
• These results argue against the involvement of Th1 or Th2 population cells in schizophrenia. IL-17 and BAFF could be valuable markers for schizophrenia.

Hypotheses regarding an immune-cytokine basis of schizophrenia have been postulated with controversial findings and a lack of data related to many cytokines. The aim of this study was to assess serum levels of Interferon-γ (IFN-γ), Interleukin-4 (IL-4), Transforming Growth Factor-β (TGF-β), Interleukin-17 (IL-17) and B-cell Activating Factor (BAFF) in schizophrenic patients and to determine correlations between cytokine levels and clinical parameters. Serum cytokine levels were measured with ELISA techniques in 60 neuroleptic-free patients on acute phase of the disease (BPRS≥40) and 28 healthy controls matched for age and sex. Current symptoms were assessed with Brief Psychiatric Rating Scale (BPRS), Positive and Negative Syndrome Scale (PANSS), Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS). No significant difference was found between patients and controls regarding IFN-γ serum levels. IL-4 was not detected in both groups. Patients exhibited significantly higher IL-17 and lower BAFF serum levels. IL-17 and BAFF levels were negatively correlated in schizophrenic patients. SANS global score was negatively correlated with IL-17 and positively correlated with IFN-γ serum levels. These results argue against the involvement of Th1 or Th2 population cells in schizophrenia. IL-17 and BAFF could be valuable markers for schizophrenia.