Development and Therapeutic Evaluation of a Uniform Lymph Node Cell Transfer Model of Alopecia Areata 2256823

Abstract Introduction Alopecia areata (AA) is an autoimmune disease characterized by non-scarring hair loss, primarily mediated by cytotoxic T-cell attack on hair follicles. To establish a reproducible and uniform preclinical model for therapeutic evaluation, we developed a lymph node cell (LNC) transfer - induced AA mouse model on the C3H background. Methods LNCs from aged C3H mice with spontaneous AA were isolated, activated, expanded in vitro, and injected intradermally into young healthy C3H mice. To evaluate the translational utility of this model, mice with established AA (>15 weeks) were treated with either oral Ritlecitinib or topical Tacrolimus for 10 weeks. Results Within 5 weeks, recipient mice developed progressive ventral hair loss, and by 15 weeks, nearly 90% exhibited severe AA with clinical scores above 5, including complete abdominal and >75% dorsal alopecia. Flow cytometry revealed elevated CD3+ T cells, CD8+ T cells, and NKG2D+ cells in both skin and lymph nodes. Immunohistochemistry and RNA analysis confirmed MHCI upregulation and NKG2D+/CD8+ T cell involvement, validating the model’s autoimmune AA phenotype. Ritlecitinib or Tacrolimus treatments significantly improved AA symptoms, with Tacrolimus group achieving near-complete hair regrowth (∼100%) and resolution of alopecia. Treatment reduced MHC-I expression and decreased CD8+ T cell infiltration in the skin, as confirmed by flow cytometry and IHC. Conclusion The LNC transfer—induced AA model provides a robust and uniform preclinical platform that recapitulates the autoimmune pathogenesis of AA and enables the evaluation of therapeutic candidates for alopecia areata. Funding Source n/a Topic Categories Therapeutic Approaches to Autoimmunity (THER)