Allergens in Household Dust and Serological Indicators of Atopy and Sensitization in Detroit Children with History-Based Evidence of Asthma

Abstract

Background. Home exposure to allergens is an important factor in the development of sensitization and subsequent exacerbations of allergic asthma. We investigated linkages among allergen exposure, immunological measurements, and asthma by examining (1) reservoir dust allergen levels in homes, (2) associations between presence of allergens in homes and sensitization status of resident children, and (3) associations between asthma status and total IgE, atopy (by Phadiatop), and positive allergen-specific tests. Methods. The study protocol was approved by Institutional Review Boards (IRBs) of the University of North Carolina Chapel Hill; Westat, Inc.; and the US Environmental Protection Agency Human Research Protocol Office. Data were collected from questionnaires, serum analyses, and household vacuum dust. Children (n = 205) were predominately African American (AA) (85.4%) and 51.6% were asthmatic. Sera from 185 children and home dust samples (n = 141) were analyzed for total and specific IgE antibodies to allergens from cat and dog dander, cockroach, dust mites, mice, rats, and molds. Results. Sixty percent of the homes had detectable levels of three or more dust allergens. The proportions of children with positive allergen-specific IgE tests were dust mite (32%), dog (28%), cat (23%), cockroach (18%), mouse (5%), rat (4%), and molds (24–36%). Children testing positive to a single allergen also had positive responses to other allergens. Those children with positive serum tests for cat, dog, and dust mite lived in homes with detectable levels of cat (51%), dog (90%), and dust mite (Der f 1) (92%) allergens. Correlations between children’s specific IgE levels and dust levels were linearly related for dog (p < .04), but not for cat (p = .12) or dust mite (Der f 1) (p = .21). Odds ratios (95% CI) for the associations between asthma and serum-specific IgE were over 1.0 for cat, dog, dust mite (Der f 1), cockroach, and four types of molds. House dust allergen exposure levels, however, exhibited no differences between asthmatic and non-asthmatic homes. Conclusions. Both the co-occurrence of multiple allergens in dust and the high frequency of multiple allergen sensitizations indicate that a broad-based intervention aimed at reducing multiple allergens (pets, pests, and molds) would be more successful than any approach that aimed at reducing one type of allergen.

• Immunological measurements
• IgE
• home exposure
• intervention

Acknowledgments

The authors are grateful to the parents, guardians, and children who participated in this study as well as the Henry Ford Health System, Detroit, Michigan, clinical teams, and laboratory staff. They also acknowledge Research Triangle Institute that conducted the dust sieving, and John Wisenauer and Katie A. Laugh at the Johns Hopkins University Dermatology, Allergy and Clinical Immunology (DACI) Reference Laboratory who analyzed the total and allergen-specific IgE antibody levels. The authors also thank Drs. Michael Madden and Marsha Ward for their helpful comments and careful review of this manuscript.

Funding. The information in this document has been funded by the US EPA. It has been subjected to review by EPA’s National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the agency.