Increased circulating skin-homing cutaneous lymphocyte-associated antigen (CLA)+ type 2 cytokine-producing cells, and decreased CLA+ type 1 cytokine-producing cells in atopic dermatitis

Background Skin-homing T cells are characterized by expression of cutaneous lymphocyte-associated antigen (CLA). Few data are a available on the frequ ency of circulating CLA+ cytokine-producing T cells in atopic dermatitis (A D) patients. Objectives We aimed to investigate cytokine synthesis capability vs. CLA ex pression in phorbol myristate acetate and ionomycin-stimulated, secretion-i nhibited peripheral blood T cells of AD patients compared with healthy subj ects and psoriatic patients. Methods Multiparameter flow cytometry was used. Results The expression of CLA among CD4+ T cells was significantly elevated in AD patients compared with healthy subjects and psoriatic patients, wher eas there was no significant difference between each group in CLA expressio n among CD8+ T cells. The frequency of interleukin (IL)-4- and IL-13-produc ing cells in AD patients was significantly higher than in healthy subjects (in both CD4+ and CD8+ T-cell subsets) and psoriatic patients (in CD4+ T ce lls). In contrast, the frequency of interferon (IFN)-gamma-producing cells was significantly reduced in AD patients, among both CD4+ and CD8+ T cells, compared with healthy subjects and psoriatic patients. Moreover, in AD pat ients, the frequency of IL-4- and IL-13-producing cells was remarkably incr eased among the CLA+ subset (in both CD4+ and CD8+ T cells), whereas the fr equency of IFN-gamma-producing cells was decreased in the CLA+ subset (in C D4+, but not in CD8+ T cells). Conclusions These results provide evidence for the expansion of skin-homing type 2 cytokine-secreting T cells, associated with a reduction in skin-hom ing type 1 cytokine-producing T cells, in peripheral blood of AD patients.