Mouse allergen-specific antibody responses in inner-city children with asthma

Background: 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. Objective: To examine relationships between mouse allergen exposure and allergen-specific IgE and IgG responses in inner-city children with asthma. Methods: 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. Results: 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 μg/g, increased among those exposed to 2-7.9 μg/g and 8-29.9 μg/g, and then decreased among participants exposed to >29.9 μg/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 (odds ratios [95% CI], 82.8 [20.5-334.4] and 50.4 [14.0-181.7], respectively). Conclusion: High-level exposure to mouse allergen in children may be associated with attenuated humoral responses of all isotypes rather than selective attenuation of IgE. Clinical implications: Protection against allergic sensitization by high-dose allergen exposure may not be mediated by preferential production of IgG over IgE.