Induction of T Cell Exhaustion by JAK1/3 Inhibition in the Treatment of Alopecia Areata

The study explores the impact of the JAK1/3 inhibitor Ifidancitinib on alopecia areata (AA) using the C3H/HeJ mouse model. Ifidancitinib effectively inhibited JAK1/3 signaling, reducing the proliferation and function of pathogenic T cells, and induced T cell exhaustion, evidenced by increased PD-1 and TIM-3 expression on CD8+ T cells. This treatment prevented the onset of AA, reversed established disease, and led to significant hair regrowth and reduced skin inflammation. The findings suggest that JAK1/3 inhibition is a promising therapeutic approach for AA by promoting long-term disease remission through T cell exhaustion.