Circulating CLA(+) lymphocytes from children with atopic dermatitis contain an increased percentage of cells bearing staphylococcal-related T-cell receptor variable segments

Background Atopic dermatitis is an allergic T-cell mediated skin inflammati on. Staphylococcus aureus colonization is very common in cutaneous atopic d ermatitis lesions. The cutaneous lymphocyte-associated antigen (CLA) is a T cell skin homing receptor that defines T lymphocytes associated with the c utaneous immune response. Objective To study whether CLA(+) T cells from atopic dermatitis children p resent a selective expression far Staphylococcus aureus-related TCR V beta segments. Methods Peripheral blood T cells were stained with HECA-452 (anti-CLA) and a panel of TCR V beta specific monoclonal antibodies and analysed by flow c ytometry. Results Atopic dermatitis patients have a higher percentage of circulating CLA(+) CD3(+) lymphocytes compared with healthy controls. Patients with act ive atopic dermatitis during the study expressed a higher percentage of cel ls positive for the TCR V beta 2 and V beta 5.1 segments in the CLA(+) but not in the CLA(-) subset. These TCR V beta s are recognized by staphylococc al superantigens. Moreover, there was an increased percentage of HLA-DR+ ex pression by CLA(+) V beta 5.1(+) T cells in patients with active atopic der matitis, but those patients whose eczema was inactive had very similar valu es to healthy controls regarding TCR V beta and HLA-DR phenotype in circula ting CLA(+) T lymphocytes. Conclusion Our data indicate that circulating skin-homing T cells of patien ts with active atopic dermatitis contain an increased percentage of cells b earing TCR V beta segments related with Staphylococcus aureus. Staphylococc us superantigens may therefore trigger expansion or at least circulation of appropriate CLA(+) T cells.