[Evaluation of atopy by antigen specific IGE antibody].

Background: Atopy is usually defined as the genetic propensity to produce IgE antibodies (Abs) specific to common environmental allergens. The aim of this study was to evaluate impacts of the number of allergens examined on prevalence of atopy.
Methods: Subjects comprised 116 healthy controls, 104 patients with asthma, 294 patients with COPD, 64 patients with sarcoidosis and 218 residents of Kamishihoro town. Total serum immunoglobulin E and antigen-specific IgE antibody levels for 26 common allergens were examined. Atopy was defined as positive IgE Abs specific to > or =1 allergen. We serially increased the number of allergens to define atopy from the most common allergens in order of frequency, and changes in prevalence of atopy were evaluated. In residents of Kamishihoro, betula pollen antigen was also examined, as this antigen is very common in the town.
Results: The increasing prevalence of atopy was dramatically reduced relative to the number of allergens examined. Among residents of Kamishihoro town, 5 cases displayed specific IgE Abs to this allergen alone and prevalence of atopy was increased 2.3 percents.
Conclusion: When atopy was defined as the production of specific IgE Abs to common allergens, roughly 10 of the most common allergens may cover common environmental allergens.