Background Previous cross-sectional surveys have suggested that maternal exposure to animal sheds during pregnancy exerted a protective effect on atopic sensitization in children lasting until school ...age. Objective We sought to evaluate the effects of maternal exposure to animal sheds and other farm-related exposures during pregnancy on cord blood IgE levels in a prospective birth cohort. Methods Pregnant women living in rural areas in Austria, Finland, France, Germany, and Switzerland were recruited in the third trimester of pregnancy. Information on maternal farm-related exposures, nutrition, and health during pregnancy was obtained by means of interviews. Specific IgE levels for food and common inhalant allergens were assessed in cord blood of 922 children and peripheral blood samples of their mothers. Results Different sensitization patterns in cord blood of farm and nonfarm children were observed. In multivariable analysis consumption of boiled, but not unboiled, farm milk during pregnancy was positively associated with specific IgE to cow's milk independently from maternal IgE. In contrast, there was an inverse relationship between maternal exposure to animal sheds and cord blood IgE levels against seasonal allergens (adjusted odds ratio, 0.38; 95% CI, 0.21-0.70). This association was not confounded by maternal IgE levels. Maternal contact with hay enhanced the protective effect of exposure to animal sheds on IgE levels to grass pollen in cord blood. Conclusions Maternal exposure during pregnancy influences atopic sensitization patterns in cord blood. The (microbial) context of allergen contact possibly modifies the risk of atopic sensitization.
Background It is currently discussed whether allergic sensitization may start in utero under the influence of the maternal immune system and environmental determinants. Objective To investigate the ...relationship between allergen-specific cord blood (CB) IgE levels, parental sensitization, CB cytokine production, and environmental influences. Methods As part of an ongoing multicenter birth cohort study, allergen-specific IgE antibodies against 20 common seasonal, perennial, and food allergens were measured in blood samples from 922 neonates, 922 mothers, and 835 fathers. Supernatants from stimulated CB cells were assessed for the production of IL-5, IFN-γ, IL-10, and TNF-α. Results Allergen-specific IgE antibodies were detectable in 23.9% of newborns. Contamination with maternal serum was excluded by several means of analyses, including the absence of IgA antibodies. Clear correlation between maternal and fetal IgE was found only for hen's egg, cow's milk, and soybean allergen. Fetal IgE correlated negatively with the level of IFN-γ production, but not with IL-5 and IL-10. Conclusion Allergen-specific IgE antibodies most probably of fetal origin are detectable in CB and correlate with a lowered CB IFN-γ production.
