Differences in antigen-specific T-cell responses between infants with atopic dermatitis with and without cow's milk allergy: Relevance of T(H)2 cytokines

Background: Cow's milk is the most important food antigen in infancy and ma y lead to acute cutaneous symptoms and atopic dermatitis (AD). The role of circulating allergen-specific T cells in the pathogenesis of food-allergic skin symptoms is still under investigation. Objective: This study was designed to analyze the cow's milk protein (CMP)- specific T-cell response at the clonal level in infants with AD and cow's m ilk allergy (CMA) in comparison with infants with AD without CMA. Methods: We used an antigen-specific culturing system with autologous B cel ls as antigen-presenting cells to establish CMP-specific T-cell clones deri ved from PBMCs in infants with AD. T-cell reactivity, measured by using a l ymphocyte stimulation test, and cytokine production, measured by using ELIS A, was compared between infants with AD with and without CMA. Results: Both infants with and without allergy to cow's milk had a CMP-spec ific T helper cell response directed against the major proteins in milk. An alysis of antigen-specific cytokine production showed that this response wa s T(H)2 skewed in infants with CMA, with production of high levels of IL-4, IL-5, and IL-13. In contrast, infants without CMA had a T(H)1-skewed respo nse, with high levels of IFN-gamma and low levels of IL-4, IL-5, and IL-13. Conclusion: These data confirm for the first time at the clonal level that food allergy in infants with AD is associated with production of T(H)2 cyto kines by circulating antigen-specific CD4(+) T cells, whereas tolerance to food antigens is associated with low levels of these cytokines. This sugges ts a key role for the T helper cell-derived T(H)2 cytokines in food allergy -related skin symptoms.