Circulating skin-homing T cells in atopic dermatitis. Selective up-regulation of HLA-DR, interleukin-2R, and CD30 and decrease after combined UV-A and UV-B phototherapy

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 lymphocyte-associated 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.