Background: The nature of allergens and route and dose of exposure may affect the natural development of IgE and IgG responses. Objective: We sought to investigate the natural IgE and IgG responses toward a large panel of respiratory and food allergens in subjects exposed to different respiratory allergen loads. Methods: A cross-sectional analysis was conducted in 340 adults of the EGEA (Epidemiological study of the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy) (170 with and 170 without asthma) cohort. IgE and IgG responses to 47 inhalant and food allergen components were analyzed in sera using allergen microarray and compared between 5 French regions according to the route of allergen exposure (inhaled vs food allergens). Results: Overall 48.8% of the population had allergen-specific IgE levels of 0.3 ISAC standardized units (ISU) or more to at least 1 of the 47 allergens with no significant differences across the regions. For ubiquitous respiratory allergens (ie, grass, olive/ash pollen, house dust mites), specific IgE did not show marked differences between regions and specific IgG (≥0.5 ISU) was present in most subjects everywhere. For regionally occurring pollen allergens (ragweed, birch, cypress), IgE sensitization was significantly associated with regional pollen exposure. For airborne allergens cross-reacting with food allergens, frequent IgG recognition was observed even in regions with low allergen prevalence (Bet v 1) or for allergens less frequently recognized by IgE (profilins). Conclusions: The variability in allergen-specific IgE and IgG frequencies depends on exposure, route of exposure, and overall immunogenicity of the allergen. Allergen contact by the oral route might preferentially induce IgG responses.

The study was supported in part by Inserm Aviesan Itmo santé publique, the Scientific committee “AGIR for chronic diseases,” grant F4605 of the Austrian Science Fund (FWF [Fonds zur Förderung der wissenschaftlichen Forschung]) to R.V. and by the European Commission's Seventh Framework 29 Program MeDALL under grant agreement no. 261357.