Resident T Cell Activation Leads to Human Hair Follicle Immune Privilege Loss Ex Vivo, Prevented by DHODH Inhibitor Farudodstat: Relevance for Alopecia Areata

This study investigates the role of hair follicle (HF) resident T cells in the immune privilege (IP) collapse associated with alopecia areata (AA). Using a human HF organ culture model, researchers activated resident T cells with αCD3/αCD28 antibodies, leading to increased T cell proliferation and signs of IP collapse, such as elevated MHC class I and II expression. The study further explored the effects of the DHODH inhibitor farudodstat, which, when administered prior to and during T cell activation, reduced T cell proliferation and prevented IP collapse. These findings suggest that while T cell activation can induce an AA-like phenotype in healthy HFs, farudodstat can mitigate these effects, highlighting its potential relevance for AA treatment.