Serum IL-17 levels in Patients with Rosacea.

BACKGROUND Rosacea is a chronic inflammatory skin disease characterized with increased serum and tissue inflammatory mediators. IL-17 is a well-known inflammatory mediator that plays important roles in pathogenesis of inflammatory skin diseases. Previous studies reported that Th17 pathway is activated in rosacea and IL-17, one of Th17 signature cytokines, is elevated in tissue samples of rosacea patients. OBJECTIVES The aim of this study was to investigate serum IL-17 levels in rosacea patients and to study its relationship with disease characteristics. METHODS Sixty patients diagnosed with rosacea and 60 healthy controls were included in the study. Serum IL-17 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS The mean serum IL-17 level was 8.03 pg/mL (sd=1.47) in rosacea patients and 7.37 pg/mL (sd=1.19) in controls. Serum IL-17 levels were significantly higher in rosacea (p=0.002). Serum IL-17 levels were similar among patients with erythematotelangiectatic (ET) and papulopustular (PP) rosacea (8.02 vs 8.06, p=0.83). Serum IL-17 levels did not correlate with rosacea severity (p=0.59, r=0.07 in ET rosacea; p=0.88, r=0.02 in PP rosacea), age of onset (p=0.58, r=-0.07) and disease duration (p=0.37, r=-0.11). Primary features and global assessments did not correlate with serum IL-17 levels (all p>0.05). Among secondary features, edema showed a significant negative correlation with serum IL-17 concentrations (p=0.037, r=-0.26). CONCLUSIONS Our study showed increased serum IL-17 levels in rosacea patients and a significant correlation between IL-17 concentrations and secondary features of the disease suggesting IL-17 may contribute to pathogenesis of rosacea and may be a new target for rosacea treatment.