ABSTRACT
PURPOSE: Skin-homing T cells expressing cutaneous lymphocyte antigen (CLA) are known to be important in the pathogenesis of atopic dermatitis (AD). So far, there have been few reports on the peripheral lymphocyte subpopulations expressing CLA, especially in children with AD. METHODS: We investigated the peripheral blood lymphocyte subpopulations expressing CLA in children with severe AD andcontrol subjects to identify which proportions of circulating CLA+ T cells were expanded in atopic dermatitis. We assayed the peripheral blood lymphocyte subpopulation with flow cytometry in 15 children with severe chronic lichenified skin lesions and 12 control subjects who had no symptoms of atopic dermatitis. The expressions of peripheral blood CD4+CLA+ T cells and CD3+CLA+ T cells were significantly increased in children with AD compared with those in control subjects, whereas there was no significant difference of CD8+CLA+ T cells between the two groups. RESULTS: The expressions of CD3+ T cells, CD4+ T cells, and CD8+ T cells showed no significant differences between children with AD and control subjects. CONCLUSION: These findings suggest that circulating CD4+CLA+ T cells play an important role in the pathogenesis of chronic severe AD in children.