Butyrophilin-Like 2 to the Rescue: Controlling Autoaggressive Dermal Gamma Delta T Lymphocytes in Human Hair Follicles

The study investigates the role of Butyrophilin-like 2 (BTNL2) in regulating interactions between gamma/delta (GDT) T cells and hair follicles (HFs), particularly in the context of alopecia areata (AA). BTNL2 is primarily expressed in the outer root sheath keratinocytes of healthy human scalp HFs. The research found that stressed HFs exhibit significantly lower BTNL2 expression, which correlates with increased cytotoxic activity by VD1 GDT and CD8+ T cells, leading to HF damage characteristic of AA. This suggests that BTNL2 plays a crucial role in maintaining immune privilege in HFs and could be a potential target for future AA treatments.