Innate Lymphoid Cells Type 1 May Be New, Non-Antigen-Specific Player in the Pathogenesis of Alopecia Areata

The study explored the role of innate lymphoid cells type 1 (ILC1) in the pathogenesis of alopecia areata (AA), an autoimmune disease traditionally associated with CD8+ T cells. Researchers found an increased number of perifollicular ILC1s in lesional AA skin compared to healthy skin. Experiments demonstrated that co-culturing human scalp hair follicles with ILC1s or CD8+NKG2D+ cells led to premature catagen development, hair follicle dystrophy, and immune privilege collapse, which are characteristic of AA. ILC1s produced large amounts of IFN-γ and induced significant hair follicle cytotoxicity, up-regulating MHC class I and II expression and decreasing hair matrix proliferation. The study suggested that ILC1s, like CD8+ T cells, could trigger AA, highlighting their potential role as non-antigen-specific contributors to the disease.