Interleukin-17A immune pattern across genetic acantholytic and blistering disorders

Abstract

Abstract There is a high therapeutic need in acantholytic and blistering genodermatoses. Cutaneous inflammation is a reasonable therapeutic target, although the patterns are not yet fully elucidated. Here we investigated by immunohistochemistry whether interleukin (IL)-17A is expressed in the inflammatory infiltrate in 34 patients with Hailey–Hailey disease, Darier disease, and junctional and dystrophic epidermolysis bullosa. There was a 5–7-fold increase in the number of IL-17A-positive cells in all patients’ samples as compared with normal skin. IL-17A cells were present in epidermal acantholytic areas and dermal inflammatory infiltrates in Hailey–Hailey and Darier disease. In epidermolysis bullosa samples, positive cells were present at the dermoepidermal junction zone. The IL-17A inflammatory pattern was validated by observing upregulation of downstream genes/proteins, S100A7, S100A8 and S100A9 (S100 calcium-binding proteins). These results suggest that IL-17A contributes to skin inflammation and could be a therapeutic target during inflammatory flares in these disorders.