Maternal influence on IgG subclass antibodies to Bet v 1 during the first 18 months of life as detected with a sensitive ELISA

Background: The initial encounters with allergens are crucial for sensitisation later in life. The IgG1 responses to house dust mite in infancy are later accompanied by an IgG4 response, with high levels seen particularly in atopic children. Little is known of the development of IgG subclass responses to other inhalant allergens. The aims of this study were to develop a sensitive method for the study of postnatal immune responses to the important seasonal inhalant allergen Bet v 1. Methods: Antibodies to rBet v 1 were analyzed in 96 children at birth, 6 and 18 months using a sensitive enzyme-amplified ELISA. Results: Immunoglobulin G responses to rBet v1, mainly of the IgG1 subclass, were common in young children, and could at 6 months be demonstrated in several infants who had not yet experienced a postnatal birch pollen season. Atopic dermatitis was associated with high levels of lgG subclass antibodies to birch at 18 months. Maternal atopy was associated with high levels of all IgG subclass antibodies to rBet v 1 in cord blood. In postnatally birch-pollen-exposed infants with atopic mothers, the levels of IgG antibodies at birth correlated with the levels at 6 months. In contrast, high antibody levels to rBet v 1 at birth were associated with low IgG titres to rBet v 1 at Is months. Conclusions: IgG1 responses to birch are common during the first 18 months of life. High levels of maternally derived birch-specific IgG antibodies are associated with maternal atopy and may influence the development of the IgG antibody responses to birch in their child.