Differentiation of T-helper cells in distinct phases of atopic dermatitis involves Th1/Th2 and Th17/Treg

The aim of this article is to study T-helper (Th) cell differentiation in the progression of acute, subacute, and chronic atopic dermatitis. Skin biopsies from 48 patients with acute, subacute, and chronic atopic dermatitis were studied using immunohistochemistry with antibodies to TARC/CCL17, CTACK/CCL27, and RANTES/CCL5. Peripheral blood mononuclear cells were studied in 17 patients using flow cytometry to measure the content of Th1/Th2 cells and Th17/Treg cells. Levels of interferon (IFN)-gamma, interleukin (IL)-4, IL-17A, and transforming growth factor (TGF)-beta 1 were evaluated with enzyme-linked immunosorbent assay (ELISA). Distinctive expressions of T-cell-specific chemokines TARC/CCL17, CTACK/CCL27, and RANTES/CCL5 were observed at different stages of atopic dermatitis, which were consistent with the differentiation of the Th cell subsets, Th2/Th1, and Th17/Treg. Th2 and Th17 were acute-phase subsets, while Th1 and Treg were chronic-phase subsets. At an early stage of atopic dermatitis, Th17 and Th2 cells were found in peripheral blood mononuclear cells, followed by Th1 cells, Treg cells, and eosinophils; in late-stage or subacute and chronic atopic dermatitis, Th17 and Th2 cell numbers decreased. The levels of the IFN-gamma and TGF-beta 1 increased during the progression of atopic dermatitis from acute to chronic forms. The levels of IL-17A and IL-4 decreased during the progression of atopic dermatitis from acute to chronic forms. The differentiation of Th subsets at distinct phases in atopic dermatitis may form the basis for further studies on the classification or control of this increasingly common clinical condition.