Predominant expression of interleukin (IL)‐17 in chronic alopecia areata compared to IFN‐γ in pathogenic Th17 cells, tissue‐resident memory T cells and natural killer cells

Backgrounds Alopecia areata (AA) is an organ-specific autoimmune disease resulting from the attack of hair follicle (HF) autoantigens through a T-cell-mediated mechanism. If there depletion mTregs in HFs, especially around both bulge and bulb, it could be related to patchy loss scalp may affect AA pathogenesis. Objectives we investigated possible contributory role tissue-resident memory T cells (TRMs) regulatory (mTregs), compared cytotoxic lymphocytes Th17 lymphocytes, immunopathogenesis chronic AA. Methods Three hundred sixty-seven patients with who had biopsies performed Dong-A University Hospital between January 1994 April 2019 were retrospectively reviewed. To investigate expression immunoregulatory molecules, underwent double direct immunofluorescence paraffin sections nine under classified according histopathological grading Uno Orecchia's classification. Results The number lesional Foxp3+ Tregs was significantly decreased increase severity gradings at following order: Type 1 > type 2 3 lesions. CD8+ CD69+ TRM HF bulb increased grades. CD49a not expressed any As for profile effector cells, interleukin (IL)-17 denser pattern more severe grading, but IFN-γ only Lesional IL-17 also grade. In contrast, Conclusion insidious destruction stem matrix which mediated by lymphocyte infiltration, results play important pathogenesis than IFN-γ.