The influence of early environmental exposures on immune development and subsequent risk of allergic disease.

Environmental exposures in pregnancy and the early postnatal period affect early immune development. Early immune function and future allergy susceptibility appear to result from a combination of maternal phenotype, infant genotype, and environmental exposures in utero that affect early gene expression. Furthermore, epigenetic changes in gene expression in one generation can also be inherited across subsequent generations, potentially amplifying heritable allergy risk.