Increased circulating Th17 cells and elevated serum levels of TGF-beta and IL-21 are correlated with human non-segmental vitiligo development.

Although non-segmental vitiligo (NSV) results from the autoimmune destruction of melanocytes, the detailed immune mechanisms have not yet been fully elucidated. Th17 cells have been identified to be implicated in human autoimmune diseases. In this study, the frequencies of peripheral blood Th17 cells and serum levels of IL-17A and Th17 cell-related cytokines were examined in 45 patients with active NSV compared to 45 race-, gender-, and age-matched healthy controls. Our results showed increased circulating Th17 cell frequencies and elevated serum IL-17A, TGF-β1, and IL-21 levels in patients with NSV. Meanwhile, the increased Th17 cell frequencies are positively correlated with serum TGF-β1 level, and the body surface area of lesions is positively correlated with elevated TGF-β1 and IL-21 levels and Th17 cell frequencies. Furthermore, positive correlation was identified between Th17 and Th1 cell frequencies in patients with NSV. These results further indicate the potential involvement of Th17 cells and the collaborative contribution of Th17 and Th1 in NSV development, and suggest that the elevated serum TGF-β1 and IL-21 levels could contribute to enhanced Th17 cell differentiation in NSV.