Unravelling The Role Of JAK3/TEC Kinase Signalling With Ritlecitinib In Alopecia Areata Lesional Skin And Alopecia Areata-Induced Human Hair Follicles Ex Vivo

The study investigates the role of JAK3/TEC kinase signaling in alopecia areata (AA) and the effects of ritlecitinib, an FDA-approved JAK3/TEC inhibitor. In healthy hair follicles, TCR activation increased T-cell numbers, cytokine secretion, and MHC expression, all of which were prevented by ritlecitinib treatment. In chronic lesional AA skin, increased JAK3 signaling and T-cell activity were observed, which ritlecitinib effectively reduced. The findings suggest that JAK3/TEC signaling is active in AA and that ritlecitinib can inhibit this pathway, reducing AA symptoms by preventing T-cell expansion and maintaining hair follicle immune privilege.