Collapse and Restoration of Hair Follicle Immune Privilege Ex Vivo: A Model for Alopecia Areata

Alopecia areata (AA) is a hair follicle (HF) autoimmune disease leading to hair loss. Interferon gamma (IFNγ) is regarded as the key cytokine involved in AA development, which has been shown to play a role in the collapse of HF immune privilege (IP), CD8⁺ T-cell-driven inflammation toward the HF bulb, and premature catagen development. We present here the procedure to induce IP collapse in human healthy HFs ex vivo. This assay can be suitable not only to investigate mechanisms involved in HF IP collapse but also to test substances for either preventing and/or reversing HF IP collapse for the management of AA or other autoimmune diseases sharing similar pathogenesis.