Clues from alopecia areata on the role of neuropeptides in the initiation of autoimmunity.

A fascinating question regarding the pathogenesis of alopecia areata is the potential linkage with the brain. Siebenharr et al. demonstrate that substance P fibers are increased in early lesions, and that substance P treatment induces catagen follicles along with activated CD8+ T cells. Potentially, neuropeptides serve as the initial insult resulting in loss of tolerance and autoimmune disease.