Early allergen introduction overrides allergy predisposition in offspring of horses with

Introduction: The origins of allergy are both genetic and environmental. We performed a full-sibling study to determine the role of early-in-life or delayed allergen introduction on Methods: The study included four cohorts that lived together in the same environment, only differing in the timing of allergen exposure and the transfer of allergen-specific maternal antibodies. The parent cohort was first exposed to allergens in adulthood, and each full-sibling cohort was first exposed to allergen either in puberty or at birth. All full-siblings had at least one allergic parent with an allergic phenotype, suggesting a predisposition to develop allergy. Allergen-specific IgE and IgG isotypes were measured before and after exposure to Results: The rate of allergy development was inversely related to the timing of allergen exposure where introduction in adulthood led to the highest rate of allergy development (62.5%), a moderate allergy rate was found for introduction during adolescence (21.4%), and no individuals exposed at birth developed Discussion: We provide strong evidence in a full-sibling study that early-in-life allergen exposure, independent of maternal allergen-specific immunoglobulin, prevents