Background: Many studies have indicated that immune dysfunction might be involved in the physiopathology of schizophrenia and aggression. This study aimed to investigate the correlation between high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-10 and clinical characteristics, especially aggression, and to explore the potential role of hsCRP and IL-10 as plasma biomarkers of schizophrenia. Methods: Forty-one patients with schizophrenia and forty healthy individuals were enrolled. Psychopathological severity and aggression were assessed using the Positive and Negative Syndrome Scale (PANSS) and Modified Overt Aggression Scale (MOAS). Plasma concentrations of hsCRP and IL-10 were assessed by enzyme-linked immunosorbent assay (ELISA). Results: (1) Higher levels of hsCRP (p < 0.001), lower levels of logIL-10 (p < 0.001) and higher ratio of hsCRP to IL-10 (p < 0.001) were observed in the plasma of patients with schizophrenia, compared to healthy controls; (2) ROC (receiver operating characteristic) curve analysis revealed that ratio of hsCRP/IL-10 (predictive value: 0.783, p < 0.01; sensitivity: 85.4%; specificity: 67.5%) was more applicable as a biomarker to distinguish patients with schizophrenia from the control group than hsCRP and IL-10 alone (predictive value: 0.718, p < 0.01; 0.275, p < 0.001, respectively); (3) we found positive correlations between hsCRP and the total score and verbal aggression score of MOAS (r = 0.654, p < 0.01; r = 0.678, p < 0.05), and between hsCRP/IL-10 and the total score of MOAS (r = 0.636, p < 0.01). Conclusions: Our results suggest the possible function of hsCRP and IL-10 in the pathogenesis of schizophrenia and the possible value of hsCRP/IL-10 as a potential peripheral biomarker of schizophrenia. This finding also suggests a relationship between hsCRP, IL-10 and their ratio with aggression in patients with schizophrenia. (C) 2017 Elsevier B.V. All rights reserved.