Intracellular production of IL-2, IL-4, IFN-γ, and TNF-α by peripheral blood CD3+ and CD4+ T cells in children with atopic dermatitis

The role of the type-2 T helper (Th2) cell-mediated immune response in the immunopathogenesis of atopic dermatitis (AD) is well documented. Whether polarized immunoresponse is confined to antigen-specific T cells or is distributed among all T cell subsets is still controversial. We investigated frequencies of interleukin-2 (IL-2), IL-4, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) producing CD3+ and CD4+ T cells in peripheral blood from children with atopic dermatitis and healthy subjects with and without in vitro stimulation. Children with severe AD had a significantly lower percentage of CD4+ T cells spontaneously expressing IL-4 compared with healthy controls (p <0.01). Polyclonal stimulation significantly increased cytokine production in both AD patients and healthy individuals. Frequencies of CD3+ and CD4+ producing IL-2, IL-4, IFN-γ, and TNF-α after in vitro stimulation with phorbol-12-myristate 13-acetate (PMA) + ionomycin were comparable in the AD and control groups. In response to PMA/ionomycin, children with AD and asthma symptoms had a significantly lower percentage of CD3+ T cells producing TNF-α. We failed to demonstrate evidence of an imbalance with respect to type-2 cytokine productions in children with AD. Comparable induction of Th1 and Th2 cytokines in polyclonally stimulated peripheral CD3+ and CD4+T cells from AD patients and controls puts into question the polarized Th2 immune response as a general characteristic of T cells in children with atopic dermatitis.