Comparison of interleukin-17- producing cells in different clinical types of alopecia areata.

T helper 17 cells, characterized by interleukin-17 (IL-17) production, play a critical role in the pathogenesis of autoimmune disease, including alopecia areata (AA). In this report, we employed immunohistochemical staining for IL-17-producing cells, as well as interferon-γ-producing cells, granulysin-bearing cells and Foxp3+ regulatory T cells, and performed a quantitative analysis of IL-17-producing cells in the lesional skin of several clinical forms of AA by TissueFAXS analysis. Among them, interestingly, the ratio of IL-17-producing cells in acute, diffuse and total alopecia was significantly lower than those of multiple types of AA. Our study sheds light on one of the possible immunological mechanisms of AA.