Expression of and responses to CD2 and CD3 in 18-month-old children with and without atopic dermatitis

We hypothesize that atopy is associated with a reduced T-cell function earl y in life and an imbalance in cytokine production. The purpose of this stud y was to investigate the expression of and responses to CD2 and CD3 in chil dren who did or did not develop atopic dermatitis early in life, The expres sion of CD2 and CD3 was analyzed by flow cytometry, and proliferation of CD 2 and CD3 was studied by H-3-thymidine incorporation in phytohaemagglutinin (PHA)- and anti-CD3-stimulated peripheral blood mononuclear cells (PBMC) o f 18-month-old children, 25 with and 29 without atopic dermatitis. Exogenou s interleukin (IL)-2 was added to compensate for possible functional differ ences in accessory cells. Anti-CD3-induced secretion of IL-4, IL-5, IL-6, I L-10, IL-13, and interferon-gamma (IFN-gamma) was analyzed by enzyme-linked immunosorbent assay (ELISA). Atopy was associated with a low proportion of CD2(+) lymphocytes. Responsiveness to PHA, which activates lymphocytes par tly via the sheep erythrocyte receptor, CD2, was reduced in the allergic ch ildren. The anti-CD3-induced proliferation declined more rapidly with antib ody dilution in the allergic than in the non-allergic children. Atopic derm atitis was associated with high levels of anti-CD3-stimulated IL-5 secretio n. The IL-4/IL-10 and IL-4/IFN-gamma ratios were higher in children with el evated total immunoglobulin E (IgE) levels. Skin prick test-negative childr en with eczema produced higher levels of IL-10 than skin prick test-positiv e children. In conclusion, atopic children have a reduced T-cell function. Atopic dermatitis is associated with increased IL-5 production, while high total IgE levels are associated with high IL-4/IFN-gamma and IL-4/IL-10 rat ios.