Johns Hopkins Bloomberg School of Public HealthCenter for Childhood Asthma in the Urban Environment Project DescriptionThe long-term goals of this Center are to examine how exposures to environmental pollutants and allergens may relate to airway inflammation and respiratory morbidity in children with asthma living in the inner city of Baltimore, and to search for new ways to reduce asthma morbidity by reducing exposure to these agents. To accomplish these goals the Center includes both basic and applied research programs in combination with a community-based intervention research project. The first project is a community-based epidemiologic study of 400 children 6-12 and their homes to identify relevant airborne exposures and to examine genetic determinants of asthma morbidity resulting from these exposures. The second project is community-based participatory research project that is a randomized controlled clinical trial in 120 children of the effectiveness of behavioral methods to reducing pollutant and allergen exposures and their adverse health effects. The third project examines the mechanisms by which particulate matter may exacerbate an allergen-driven response in of the airways. The fourth project examines the effects of environmental particulates on the in vitro maturation of peripheral blood monocytes to dendritic cells. These projects are supported by core facilities for data management and exposure assessment. Another core facility increases the Center's existing community outreach and translational activities. An Administrative Core supports research and general meetings to integrate the interests and activities of the Center. A community advisory committee contributes to both the environmental epidemiology project and the community-based intervention research project planning, and meets periodically with Center researchers to discuss the Center's findings and progress. A seven-member External Advisory Committee has been recruited. Information gained by this coordinated interdisciplinary team allows rational plans to be made for future studies to examine susceptible children and to plan even more effective interventions in future studies with collaborating families in the East Baltimore community. Project HighlightsMouse allergen exposure is strongly associated with inner-city asthma morbidity Although mouse allergen exposure is common in inner-city homes, little is known about the relationships between exposure and humoral immune responses to mouse allergen in this population. Center investigators examined the relationships between mouse allergen exposure and allergen-specific IgE and IgG responses in inner-city children with asthma. Inner-city children with asthma underwent skin testing and venipuncture for determination of mouse allergen-specific IgE and IgG levels. Settled dust samples were collected from their homes for allergen analysis. The study population (n = 112) was predominantly African-American (92%) with a mean age of 4.4 years. The prevalence rate of mouse sensitization was 25%, and did not consistently increase with increasing Mus m 1 levels. Instead, the prevalence rate was lowest among those exposed to < 2 ug/g, increased among those exposed to 2-7.9, and 8-29.9 ug/g, and then decreased among participants exposed to > 29.9 ug/g (14%, 20%, 40%, and 28%, respectively). Similarly, the prevalence rates of mouse allergen-specific IgG and IgG4 did not increase across increasing exposure categories. Mouse allergen-specific IgG and IgG4 were strongly associated with IgE-sensitization (OR [95% CI]: 82.8 [20.5-334.4] and 50.4 [14.0-181.7], respectively). Center investigators therefore concluded that high level exposure to mouse allergen in children may be associated with attenuated humoral responses of all isotypes, rather than selective attenuation of IgE. As a result, protection against allergic sensitization by high dose allergen exposure may not be mediated by preferential production of IgG over IgE. [Matsui EC, Eggleston PA, Breysse PN, Rand CS, Diette GB. Mouse Allergen-specific Antibody Responses in Inner-city Children with Asthma. J Allergy Clin Immunol In Press.] Indoor PM from inner-city Baltimore homes is significantly associated with asthma morbidity |
|