Involvement of ILC1-Like Innate Lymphocytes in Human Autoimmunity: Lessons from Alopecia Areata

This document reports on a study that investigated the role of innate lymphoid cells-type 1 (ILC1) in the development of alopecia areata (AA). The researchers found that ILC1 were significantly increased around hair follicles (HFs) in AA patients. They conducted experiments where autologous circulating ILC1-like cells (ILC1lc) were co-cultured with stressed human scalp HFs, which resulted in the induction of AA characteristics such as premature HF regression, cytotoxicity, and the collapse of immune privilege. These effects were mitigated by blocking NKG2D or neutralizing IFNγ. Furthermore, injecting activated ILC1lc into human scalp skin grafted onto mice led to the rapid formation of AA lesions. This study provides the first evidence that ILC1lc alone can induce AA in human HFs both ex vivo and in vivo, challenging the prevailing belief that AA is solely a CD8+ T cell-driven autoimmune disease.