Expression and clinical significance of IL-17 in idiopathic inflammatory myositis / 中华风湿病学杂志

ABSTRACT

Objective:In this study, the role of IL-17 in the pathogenesis of idiopathic myositis (IIM) was preliminarily investigated by detecting the expression of IL-17 in the muscle tissues of patients with idiopathic inflammatory myositis (IIM) and normal controls.Methods:Twenty-eight patients (20 in DM group with dermatomyositis and 8 in ASS group with anti-synthase syndrome) who were diagnosed with IIM after muscle biopsy and autoantibody detection in our hospital for the first time from October 2019 to August 2021 were included. Twelve cases with normal muscle tissue matched for age and sex were included as the control group. Western blot and immunohistochemical techniques were used to detect the expression level of IL-17 in muscle tissue, and enzyme-linked immunosorbent assay (ELISA) was used to detect serum IL-6. Mann-Whitney U rank sum test was used to compare the difference of IL-17 expression in muscle tissue between the two groups, and non-parametric test was used for comparison between multiple groups. Chi-square test and Spearman rank correlation analysis were used, and P<0.05 was considered statistically significant. Results:① The expression level of IL-17 in IIM muscle tissue[1.63(1.30, 2.05)pg/ml was higher than that in control group[1.00(0.96, 1.00)pg/ml, and the difference was statistically significant ( Z=-3.52, P<0.001). The difference be-tween DM[1.94(1.58, 2.14)pg/ml] and ASS[1.22(1.04,1.55)pg/ml was statistically significant ( Z=-3.20, P=0.001). ② Compared with healthy control group [4.08(3.01, 5.67)pg/ml, the expression of IL-6 in ⅡM serum[8.88(4.93, 13.64) was high ( Z=-3.01, P=0.003), which was positively correlated with the expression of IL-17 ( r=0.42, P=0.027). ③ The ex-pression of IL-17 in muscle tissue was higher in IIM associated with muscle weakness[1.91(1.56, 2.14) pg/ml vs 1.50(1.04, 2.00)pg/ml] ( Z=-1.38, P=0.020), dysphagia [2.06(1.99, 2.14)pg/ml vs 1.62(1.52, 2.04)pg/ml] ( Z=-2.74, P=0.010) and skin involvement[1.98(1.57, 2.14)pg/ml vs 1.04(0.86, 1.61)pg/ml] ( Z=-3.20, P<0.010), and the differences were statistically significant ( P<0.05). ④IL-17 was positively correlated with Myoact-total activity ( r=0.51, P=0.006), Myoact-muscle symptom ( r=0.45, P=0.016), erythrocyte sedimen tation ( r=0.48, P=0.020), and myoenzyme increase ( r=0.56, P=0.002). Conclusion:IL-17 and IL-6 are synergistically involved in the pathogenesis of IIM, suggesting that IL-17 is the therapeutic target of IIM.