Associations Between Circulating Interleukin-17 Levels and Systemic Lupus Erythematosus and Between Interleukin-17 Gene Polymorphisms and Disease Susceptibility: A Meta-analysis

Abstract

Objective. To systematically investigate the relationship between circulating interleukin-17 (IL-17) levels and systemic lupus erythematosus (SLE) and associations between polymorphisms in IL17 genes and SLE susceptibility. Methods. We performed a meta-analysis of serum/plasma IL-17 levels in patients with SLE and controls and evaluated the associations between the IL17A rs2275913, IL17F rs763780, and IL17F rs2397084 polymorphisms and IL17F copy number variations (CNVs) and risk of SLE. Results. Thirteen studies focusing on 2,096 patients with SLE and 2,587 controls were included. Our meta-analysis revealed that IL-17 levels were significantly higher in the SLE group than the control group (standardized mean difference=1.045, 95% confidence interval [95% CI]=0.521 similar to 1.568, p<0.001). Subgroup analysis using sample size showed increased IL-17 levels in samples from large (n>100) but not small (n<90) SLE groups. We found no evidence of associations between SLE and the IL17A rs2275913, IL17F rs763780, and IL17F rs2397084 polymorphisms. However, a significant association was found between SLE and IL17F CNVs in a pooled cohort of affected individuals compared to that in pooled controls (odd ratio=3.663, 95% CI = 2.466 similar to 5.221, p<0.001). Conclusion. This meta-analysis revealed significantly higher circulating IL-17 levels in patients with SLE and showed evidence of associations between IL17F CNVs and SLE.