In the initial phases of alopecia areata, the overproduction of interferon-gamma (IFN-γ) induces the expression of major histocompatibility complex (MHC) class I in hair follicles by upregulating chemokines of the C-X-C motif (CXCL) and intracellular adhesion molecules (ICAM). The gene discussed is IFNG; the disease is alopecia areata.