Measurement of T-helper cytokines secreted by cord blood mononuclear cells in response to allergens.

It has been proposed that in utero factors may predispose towards the development of childhood atopy. To test this hypothesis, it will be necessary to measure T-helper cell (Th) cytokines secreted by human cord blood mononuclear cells (CBMC) stimulated by allergens. However, to date, it has proven impossible to measure allergen-specific CBMC secretion of the key Th cytokine interleukin-4 (IL-4) using conventional sandwich ELISA techniques. We report for the first time the successful measurement of IL-4 secreted by CBMC stimulated by the allergens timothy grass pollen and house dust mite extract. The method is an adaptation of a novel cell-based ELISA (celELISA), which demonstrated an increased (up to 20-fold) sensitivity to detect IL-4. The method is simple, precise, is no more costly than a conventional ELISA, and can identify individuals in a general population whose CBMC exhibit different cytokine biases in response to allergens. The frequency distribution of IL-4 and interferon-gamma (IFN-gamma) CBMC responses to allergens in the general population approximates to a log-normal distribution, which will permit the application of linear regression techniques in the identification of in utero factors which influence Th bias.