The profile of cytokines (IL-2, IFN-γ, IL-4, IL-10, IL-17A, and IL-23) in active alopecia areata

Background Alopecia areata (AA) is an autoimmune disease due to aberrant T-cell response against hair follicle self-antigens. Previous studies support the role of Th1 cytokines in pathogenesis of AA, but the role of Th2, Th17, and Treg cytokines remains to be fully elucidated. Objectives To assess the serum levels of cytokines secreted by Th1 (IL-2, IFN-gamma), Th2 (IL-4), Th17 (IL-23, IL-17A), and Treg (IL-10) pathways in patients of active AA and to correlate their levels with the severity of the disease. Material and methods Forty patients with untreated active AA of the scalp and forty age- and sex-matched healthy controls were included. Serum levels of cytokines IL-2, IFN-gamma, IL-17A, IL-23, IL-4, and IL-10 were measured using enzyme-linked immunosorbent assay. Results Serum levels of cytokines IL-2, IFN-gamma, IL-17A, and IL-10 were significantly raised while serum levels of IL-23 were nonsignificantly raised in AA patients as compared to controls. The levels of IL-4 were significantly lower in AA patients as compared to controls. (P < 0.05). Also, significant positive correlation was found between increase in SALT Score and serum levels of IL-2, IL-17A, and IL-23. (P < 0.05). Conclusion Th1 and Th17 pathways play a central role in the initiation and progression of AA, while Th2 pathway is suppressed in active AA. Treg pathway may be opposing Th1 and Th17 pathway and causes disease localization. The instant study lays the groundwork for understanding the pathogenesis of AA and suggests the role of implicated cytokines as potential therapeutic targets and as biomarkers of disease activity.