Elevated circulating interleukin-17 levels in systemic sclerosis: a meta-analysis.

Abstract

Objective: The aim of this meta-analysis was to evaluate the association between circulating interleukin-17 (IL-17) levels and systemic sclerosis (SSc).

Methods: We conducted a comprehensive systematic search in MEDLINE, Embase, and Web of Science for relevant studies. The meta-analysis compared serum/plasma IL-17, IL-17A, IL-17B, IL-17E, and IL-17F levels in SSc patients with those in control subjects, incorporating subgroup analyses based on ethnicity and disease subtype.

Results: This analysis included 16 studies, comprising 1,229 patients diagnosed with SSc and 839 control participants. The meta-analysis did not identify a significant difference in circulating IL-17 levels between SSc patients and controls in overall group (standardized mean difference [SMD]=0.260; 95% confidence interval [CI]=-1.805 to 2.336; p=0.825). However, recent studies supported this finding, demonstrating a stronger association (SMD=2.040; 95% CI=1.049 to 3.030; p<0.001). IL-17A levels were significantly higher in SSc patients (SMD=2.046; 95% CI=0.724 to 3.369; p=0.002), along with notable increases in IL-17B (SMD=0.764; 95% CI=0.230 to 1.298; p=0.005), IL-17E (SMD=0.672; 95% CI=0.282 to 1.062; p=0.001), and IL-17F (SMD=0.402; 95% CI=0.019 to 0.784; p=0.039). However, no significant difference in IL-17A levels was observed between diffuse and limited SSc groups.

Conclusion: IL-17A, IL-17B, IL-17E, and IL-17F were significantly elevated in SSc, with IL-17A demonstrating the most pronounced association. These findings suggest that specific IL-17 subtypes, particularly IL-17A, play a role in SSc pathogenesis.