The research on the expression of serum IL-31 and disease activity in patients with lupus nephritis

Objective To discuss the expression of serum IL-31 in patients with lupus nephritis(LN) and its correlation with kidney disease activity. Methods The clinical data of 54 patients with LN diagnosed in the First People's Hospital of Jiujiang during the baseline and follow-up period(experimental group) were analyzed prospectively.Another 28 healthy people(control group) were selected from the physical examination center.The expression of serum IL-31 in each group was detected by ELISA.Its correlation with disease activity index was analyzed by Spearman correlation analysis.Result A total of 54 patients in LN experimental group were divided into active group(38 cases) and stable group(16 cases) according to whether the SLEDAI(SLE disease activity index) score was≥10.There was a significant difference in serum IL-31 expression between the two groups(83.7±16.2 vs.72.5±14.1) ng/L(P=0.019).There was significant difference between the two groups and the healthy control group(30.6±9.8) ng/L.The level of serum IL-31 in the LN group before treatment was significantly higher than that after immunosuppressive therapy(81.2±15.7 vs.71.4±16.3) ng/L(P=0.001).Spearman correlation analysis showed that the serum level of IL-31 in the experimental group was positively correlated with the overall SLEDAI score(r=0.406,P=0.002),24-h urine protein quantity(r=0.529,P<0.001),and LN pathological activity index Austin score(r=0.469,P=0.011).The expression was consistent with the levels of IL-6(r=0.670,P=0.026) and TNF- α(r=0.597,P=0.019),and was negatively correlated with serum complement C3(r=-0.427,P=0.001).Conclusion The level of IL-31 in LN patients is higher than that in healthy people,and it is positively related to disease activity.