Immunoglobulin A and immunoglobulin G antibodies against β‐lactoglobulin and gliadin at age 1 associate with immunoglobulin E sensitization at age 6

Background Serum immunoglobulin A ( I g A ) and immunoglobulin G ( I g G ) antibodies against wheat gliadin and cow's milk β‐lactoglobulin ( BLG ) are considered markers of gut permeability and inflammation which modulate the development of mucosal tolerance. Living on a farm has been shown to decrease allergies in children. Our aim was to study whether farm environment affected mucosal tolerance, immunoglobulin E ( I g E ) sensitization, or allergic diseases. Methods The PASTURE birth cohort study was conducted in F inland, F rance, G ermany, A ustria, and S witzerland. At age 1, we measured serum I g A and I g G against wheat gliadin (N = 636) and cow's milk BLG (N = 639) using ELISA . Serum‐specific I g E was measured at ages 1 and 6 (N = 459). Data on environmental factors and allergic diseases were collected by questionnaires. Discrete time hazard and multivariate logistic regression models were used for analyses. Results Increased I g A or I g G antibodies against BLG at age 1 increased the risk of sensitization to at least one of the measured allergens or food allergens at age 6. Increased I g G against gliadin at age 1 increased the risk of sensitization to any, at least one inhalant, or at least one food allergen at age 6. Early exposure to cow's milk formula associated with increased I g A or I g G against BLG . No association with farming or clinical allergy was found. Conclusions Increased I g A or I g G against BLG or gliadin at age 1 was associated with I g E sensitization at age 6. We suggest that an enhanced antibody response to food antigens reflects mucosal tolerance aberrancies, e.g., altered microbiota and/or increased gut permeability, which is later seen as sensitization to allergens.