Role of interleukin-17 in the pathogenesis of vitiligo

BACKGROUND: Skewing of the immune response towards T helper (Th)1 or Th17 and away from regulatory T cells (Tregs) and Th2 cells may be responsible for the development and progression of autoimmune disease. An autoimmune theory has been proposed in the pathogenesis of vitiligo. No previous reports have investigated alterations in IL-17 produced by Th17 cells in lesional skin in vitiligo. AIM: To investigate the role of IL-17 in the pathogenesis of vitiligo by assessing its levels in lesional skin and serum of patients with vitiligo compared with controls. METHODS: In total, 30 patients with vitiligo and 20 controls matched for age and gender were enrolled in the study. Serum and tissue IL-17 levels were measured by ELISA and compared between both groups for correlations with age, gender, family history, disease duration, activity of vitiligo and percentage of involved body surface area. RESULTS: A significant difference between patients and healthy controls was found for both serum and tissue IL-17 levels (P<0.001 for both). Significant positive correlations were found between disease duration and IL-17 level in both serum (r=0.42, P=0.02) and lesional skin (r=0.45, P<0.015); between extent of vitiligo and IL-17 levels in both serum (r=0.65, P<0.001) and skin (r=0.48, P<0.05); and between the serum and the tissue IL-17 levels in patients with vitiligo (r=0.54, P=0.002). CONCLUSIONS: Multiple factors have been implicated in the pathogenesis of vitiligo. The increased levels of IL-17 we found in serum and lesional skin suggest an important role for this cytokine in the pathogenesis of vitiligo.