Phenotypic Analysis of T-Cells in Extensive Alopecia Areata Scalp Suggests Partial Tolerance

The study analyzed T-cells in the scalp of 12 patients with extensive alopecia areata (EAA) and 6 controls, finding that EAA T-cells exhibited partial tolerance with lower CD-3 expression and reduced production of Th-1 cytokines IL-2 and IFN-γ. Despite similar CD-4/CD-8 ratios and CD-69 expression indicating T-cell activation, the immune response in EAA was aberrantly regulated, suggesting mechanisms of peripheral T-cell tolerance. This unique immune environment in the hair follicle might prevent scarring and follicle destruction, offering potential therapeutic avenues.