Circulating Skin-Homing T Cells in Atopic Dermatitis

Abstract

Background: As the cutaneous lymphocyte-associated antigen appears to detect circulating T cells that migrate to the skin in atopic dermatitis but not T cells that migrate to mucosal sites in allergic asthma and rhinitis, we investigated T-cell activation markers and CD30 on the cutaneous lymphocyte-associated antigen—positive circulating T-cell subset in atopic dermatitis to see whether these markers are different from those in normal controls and related to disease activity. Design: Open study. Setting: University referral center. Patients: Twelve patients with atopic dermatitis and 12 healthy controls. Intervention: Combined UV-A and UV-B treatment for 2 months. Main Outcomes Measures: Percentage of circulating cutaneous lymphocyte-associated antigen—positive T cells that express HLA-DR, interleukin-2 receptor, CD69, CD71, and CD30 (triple-color flow cytometric analysis). Clinical score, Dermatology Life Quality Index, pruritus score, and consumption of topical corticosteroids were determined. Results: Increased relative numbers of cutaneous lymphocyte-associated antigen—positive T cells expressing HLA-DR, interleukin-2 receptor, and CD30 were found in patients with atopic dermatitis before treatment. Treatment with UV-A and UV-B was associated with clinical improvement and a decrease of levels of HLA-DR, interleukin-2 receptor, and CD30 in cutaneous lymphocyteassociated antigen—positive T cells. HLA-DR on cutaneous lymphocyte-associated antigen—positive T cells correlated significantly with the clinical score. Conclusion: Expression of HLA-DR and interleukin-2 receptor is a sensitive marker of disease activity in atopic dermatitis. Apart from giving information on disease activity in atopic dermatitis, the availability of skin-seeking T cells in the blood offers the opportunity to obtain further information on T cells that may have effector function in the skin. Arch Dermatol. 1996;132:1171-1176