Salivary Levels of Interleukin-17 in Iranian Patients With Systemic Sclerosis

Systemic sclerosis (SSc) is a rare immune-mediated rheumatic disease in which the skin, muscles, blood vessels, and internal organs are damaged through chronic inflammation. Interleukin-17 (IL-17) is a potent pro-inflammatory cytokine produced by T helper 17 (Th17) cells, and plays a critical role in many inflammatory conditions. This study aims to assess the salivary IL-17 levels in Iranian patients with SSc. In this cross-sectional study, unstimulated saliva samples were collected from patients with SSc (n=80) and age- and sex- matched healthy individuals (n=80). The salivary levels of IL-17 in all samples were measured using a commercially available enzyme–linked immunosorbent assay (ELISA) kit. The mean salivary levels of IL-17 in patients with SSc were significantly higher than the control group (199.6±38.9 pg/mL vs. 112.7±39.4 pg/mL, P<0.0001). IL-17 in the patient group had a significant positive correlation with anticentromere antibody (ACA) concentration (r=0.875, P<0.0001). The salivary levels of IL-17 showed no significant differences between males and females. Based on the results, salivary levels of IL-17 could be considered a good marker to differentiate patients with SSc from healthy subjects. Considering the role of this inflammatory cytokine in tissue inflammation and its association with ACA concentration, IL-17 might be involved in the pathogenesis of SSc; however, further comprehensive studies are needed to confirm our findings.