Association of sensitization to Alternaria allergens with asthma among school-age children

Background: Molds in the Alternaria genus, normally found on outdoor vegetation, produce some of the most common fungal allergens to elicit a skin test response. Objectives: The objectives of this study were to evaluate a serum assay for IgE antibodies to Alternaria allergens and to establish the prevalence of sensitization to Alternaria allergens among children and adults enrolled in epidemiologic studies of asthma. In addition, the significance of sensitization to Alternaria allergens as a risk factor for asthma was compared with that of sensitization to indoor allergens or pollens. Methods: Using the Pharmacia Capsulated Hydrophobic Carrier Polymer (CAP) system, we have evaluated the significance of Alternaria allergens by using sera from several epidemiologic studies of asthma, Results: Comparisons between serum assays and skin test results suggest that this in vitro assay yields results similar to those for traditional RASTs and is as sensitive as skin prick testing. In each of the groups studied, sensitization to Alternaria allergens was more common among asthmatic than control subjects, and in two studies the relationship was highly significant. Alternaria allergens were significantly associated with asthma in middle schools in Charlottesville, Virginia and Los Alamos, New Mexico hut not in Albemarle County, Virginia. Logistic regression analysis of the results for the three schools identified an association between sensitization to Alternaria allergens and asthma independent of, but not as strong as, that found between sensitization to indoor allergens and asthma (p < 0.001). Conclusions: The Pharmacia CAP system is a useful tool for measuring specific IgE to Alternaria allergens. Although not as important as sensitization to dominant local indoor allergens, sensitization to Alternaria allergens appears to be a significant independent risk factor for asthma in children in some locations of the United States.