Resident T Cell Activation Leads to Human Hair Follicle Immune Privilege Loss Ex Vivo, Which Is Prevented by the 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 MHC expression, thereby preventing IP collapse. These findings suggest that T cell activation is crucial in AA pathogenesis and that farudodstat may offer therapeutic potential by mitigating IP collapse.