Relationships among prenatal aeroallergen exposure and materna...

BACKGROUND: Whereas some evidence suggests that antigen sensitization may begin prenatally, the influence of maternal allergen exposure during pregnancy has not been fully elucidated. OBJECTIVES: We examined the relationship between prenatal maternal aeroallergen exposure and cord blood total IgE and the potential mediating/indirect effect of maternal immune response. METHODS: This study was performed in 301 mother-infant pairs enrolled in the Asthma Coalition on Community, Environment, and Social Stress (ACCESS) project, a study examining the effects of prenatal and early life social and physical environmental exposures on urban asthma risk. Dust samples collected prenatally from mothers' bedrooms were analyzed for cockroach and dust mite allergens. Cord blood was analyzed for total IgE, and maternal serum collected during pregnancy for total and specific IgE. We assessed the relationship between prenatal exposure and cord blood total IgE and the potential mediation effect adjusting for maternal age, race, education, smoking status, and dust collection season; and child's sex and season of birth. RESULTS: In multivariate models, elevated prenatal dust mite levels (>0.2 microg/g) increased cord blood IgE concentrations by 29% (P = .08), and continuous dust mite concentration was associated with a significant nonlinear increase in cord blood IgE (P = .02). Elevated prenatal exposure to cockroach allergen (>2 U/g) was not associated with cord blood IgE, but showed a significant indirect relationship through maternal total IgE (beta = 0.23; 95% CI, 0.08-0.41). CONCLUSION: These results demonstrate that maternal prenatal exposure to household allergens may affect cord blood IgE, albeit the underlying mechanism may be allergen-specific.