Sexual dimorphism in up-regulation of suppressors of cytokine signaling genes in patients with bipolar disorder

BACKGROUND: Proteins encoded by Suppressors of cytokine signaling (SOCS) genes have critical roles in the regulation of immune responses. Meanwhile, several lines of evidence support the presence of immune dysfunction in bipolar disorder (BD) patients. METHODS: In the present study, we assessed expression levels of SOCS1–3 and SOCS5 genes in peripheral blood of patients with BD and healthy subjects. RESULTS: All SOCS genes were up-regulated in patients compared with healthy subjects. However, when comparing patients with sex-matched controls, the significant differences were observed only in the male subjects except for SOCS5 which was up-regulated in both male and female patients compared with the corresponding control subjects. Significant pairwise correlations were found between expression levels of genes in both patients and controls. Based on the area under curve values, SOCS5 had the best performance in the differentiation of disease status in study participants (AUC = 0.92). Combination of four genes increased the specificity of tests and resulted in diagnostic power of 0.93. CONCLUSION: Taken together, these data suggest a role for SOCS genes in the pathogenesis of BD especially in the male subjects. Moreover, peripheral expression levels of SOCS genes might be used as a subsection of a panel of diagnostic biomarkers in BD.