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) cellmediated 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-gamma), and tumor necrosis factor-alpha (TNF- alpha) 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-gamma, and TNF- a 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- alpha. 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.