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 immune responses in human hair follicles (HFs), particularly its interaction with gamma/delta (GDT) T cells, which are implicated in alopecia areata (AA). BTNL2 is predominantly expressed in the outer root sheath keratinocytes of healthy scalp HFs. The research found that stressed HFs exhibit significantly lower BTNL2 expression, correlating with increased expression of NKG2D and IFNg in VD1 GDT cells, leading to heightened cytotoxicity and HF dystrophy. This suggests that BTNL2 expression on HF keratinocytes plays a crucial role in controlling autoaggressive dermal GDT cell responses, presenting a potential target for future AA management.