Influence of atopic heredity on IL-4-, IL-12- and IFN-γ-producing cells in in vitro activated cord blood mononuclear cells

Several reports have claimed that there is a greater risk for a child with an atopic mother to develop allergy as compared to a child with an atopic father. This suggests that the fetal environment during pregnancy might be of importance for the development of atopic disease. Both proliferative and cytokine responses have been detected in cord blood mononuclear cells (CBMC) after stimulation with allergens, suggesting allergen priming already in utero. The aim of this study was to investigate whether the atopic status of the mother influences cytokine production by CBMC. We compared interleukin (IL)-4, IL-12 and interferon (IFN)-γ-producing CBMC from children with double atopic heredity (dh), maternal atopic heredity only (mh) or no atopic heredity (nh). CBMC were stimulated in vitro with allergens (birch, ovalbumin and cat), phytohaemagglutinin (PHA) or purified protein derivative (PPD) and cytokine-producing cells were measured by the enzyme-linked immunospot assay. In response to PHA, the frequency of IL-4-producing cells, as well as the ratio of IL-4/IFN-γ-producing cells, were significantly higher in the dh group compared to the nh group. High numbers of IL-12-producing cells in response to allergens were detected, significantly highest in the nh group, followed by the dh and mh groups. Our results suggest that there is a stronger Th2 bias after in vitro stimulation of CBMC from children with atopic heredity, as reflected by higher IL-4/IFN-γ ratios in response to PHA, and lower numbers of IL-12-producing cells after allergen stimulation. Whether these differences influence later allergy development will be evaluated when the atopic status of the children is assessed at 2 years of age.