Plasma levels of Th17-related cytokines and complement C3 correlated with aggressive behavior in patients with schizophrenia.

Increasing evidence indicates that immune inflammatory processes, especially autoimmune reaction, should be considered in the pathophysiology of schizophrenia and aggressive behavior. The present study aimed to explore the correlation between immune factors (C3 and Th17-related cytokines) and aggressive behavior in schizophrenia patients. Forty schizophrenia patients and forty age- and gender-matched healthy controls participated in the study. Blood samples were assessed by ELISA upon enrollment. Positive and negative syndrome scale (PANSS) and modified overt aggression scale (MOAS) were used to estimate the severity and aggressive symptoms of schizophrenia patients. Plasma levels of IL-17, IL-23, and TGF-β1 in schizophrenia patients were significantly higher than those in healthy controls [(37.63±17.82) vs. (29.34±10.38)pg/ml, p=0.02; (101.40±135.26) vs. (13.09±5.94) pg/ml, p=0.01; (2864.57±2163.61) vs. (1839.69±1797.73)pg/ml, p=0.04], whereas C3 levels were significantly lower in schizophrenia patients [( 120,479.67± 65,612.50) vs. ( 208,060.21± 217,008.21)ng/ml, p=0.02]. IL-17, IL-23, and TGF-β1 levels were positively related to total scores of MOAS (p=0.02, p=0.02 and p=0.03, respectively) and PANSS (p=0.04, p=0.04 and p=0.02, respectively), whereas C3 levels were negatively related to total PANSS scores (p=0.03). IL-17 and IL-23 levels were positively correlated with PANSS excited component scores (p=0.04 and p=0.01, respectively). Our findings suggested that the Th17-related cytokine levels were positively related to the severity of schizophrenia and aggressive behavior, whereas C3 levels were negatively related to the severity of schizophrenia. This study demonstrated that elevated levels of Th17-related cytokines and decreased levels of C3 could be potential biomarkers for schizophrenia and aggressive behavior.