Role of T helper 17 cells and T regulatory cells in alopecia areata: comparison of lesion and serum cytokine between controls and patients

Background Alopecia areata (AA) is an organ‐specific autoimmune disease with T‐cell‐mediated attack of hair follicle autoantigens. As T helper 17 (Th17) cells and T regulatory (Treg) cells are crucially involved in the pathogenesis, the role of Th17 and Treg cytokines has not been studied yet. Objective To determine whether AA is associated with alterations in lesional and serum Th17 and Treg cytokines and studied whether they were associated with clinical type. Methods Scalp skin samples from 45 patients and eight normal controls were obtained for PCR specific for IFN‐γ, TNF‐α, TGF‐β, IL‐1, IL‐2, IL‐4, IL‐10, IL‐12A, IL‐13, IL‐17, IL‐22 and IL‐23. Serum cytokines were measured from 55 patients and 15 normal controls using ELISA. Results Lesional IL‐17 and IL‐22 were significantly increased in patient group. Moreover, positive correlations were shown between lesional IL‐17, IL‐22 and disease severity. Serum IL‐1, IL‐17, TNF‐α and TGF‐β were significantly increased, and positive correlation was shown between serum IL‐17 and disease severity. Conclusion These results showed significantly high Th17 cytokines in both lesion and serum in AA patients, which may highlight a functional role of these cytokines in the pathogenesis of AA.