Increased Expression of p-STAT3/IL-17 in Muscle Tissues of Patients with dermatomyositis and anti-synthetase syndrome Is Correlated with Disease Activity

Abstract

Objective: To explore the roles of phosphorylated signal transduction and activator of transcription 3 (pSTAT3) and interleukin (IL)-17 expression of muscle in the disease activity of patients with idiopathic inflammatory myopathy (IIM). Methods: Twenty-eight patients with IIM (20 with dermatomyositis [DM] and 8 with anti-synthetase syndrome [ASS]) and 12 healthy controls (HCs) were enrolled in the study. The expression levels of p-STAT3 and IL-17 in muscle tissues were examined using Western blotting and immunohistochemical analyses. Results: The expressions of pSTAT3 were detected in atrophic and necrotic muscle cells around muscle fibers and in infiltrating inflammatory cells around blood vessels in DM patients and in mononuclear cells surrounding myocytes in ASS patients. The expressions of IL-17 were detected in muscle fibers and in infiltrating inflammatory cells around blood vessels in DM and ASS patients. However, they were not detected in the muscle tissue in HCs. Thus, the expression levels of p-STAT3 and IL-17 were significantly greater in the patients with IIM than in the HCs (P<0.05). Additionally, the p-STAT3 was positively correlated with the levels of IL-17in the muscle tissue ( r = 0.418, p = 0.027), IL-6 in the serum (r = 0.579, p = 0.001) , MYOACT score (r = 0.585, p = 0.001) , and the levels of AST (r =0.622, p < 0.001) , CK (r =0.714, p < 0.001) , LDH (r = 0.590, p = 0.001) , and HBD (r = 0.555, p = 0.003). Conclusion: The STAT3/IL-17 pathway is over-activated in patients with PM/ASS and plays a significant role in the disease activity.