CD4+ memory T cells in peripheral blood are not decreased in patients with atopic dermatitis.

Atopic dermatitis (AD) is a severe and chronic eczematous skin disease, to which increased IgE levels and imbalances of CD4+ T cells are related. CD4+ T cells, however, are heterogeneous and include at least two subpopulations being designated as CD4+ naive and memory T cells. They represent sequential maturational stages (naive into memory) in CD4+ T cell development differing in function and phenotype. Of these two subpopulations the CD4+ memory T cell compartment is a potent producer of gamma-interferon which suppresses IgE synthesis in B cells. Therefore, we speculated whether an inborn maturation defect of CD4+ memory T cells causes the increased IgE production in AD. In patients with AD and age- and sex-matched controls (both n = 10) we analyzed the distribution of both subpopulations in peripheral blood by two-color flow cytometry using monoclonal antibodies against the CD4, CD45RA and CD29 antigen. We provide evidence that the numerical values of CD4+ memory T cells and CD4+ naive T cells are equivalent in both groups. This supports the view that functional disturbances of lymphocytes or lymphocyte subsets are responsible for IgE excess and the pathogenesis of AD.