Relevance of low specific IgE levels to egg, milk and peanut in infancy.

BackgroundIgE sensitization is usually associated with allergy-related diseases, but may also occur in asymptomatic individuals. The clinical importance of IgE antibody concentrations in the interval 0.1-0.34kU/L in early life in relation to allergy development is poorly evaluated. ObjectiveTo assess the relevance of low specific IgE (s-IgE) to hen's egg, cow's milk and peanut at 6months of age for development of sensitization and allergy-related disease during early childhood. Methodss-IgE concentrations to relevant allergens from blood samples taken at 6months and 1, 2 and 5years from children in the prospective ALADDIN cohort were divided into three categories: non-sensitized (<0.1kU/L), low sensitized (0.1-0.34kU/L) and sensitized (0.35kU/L) and allergy-related disease assessed. ResultsA total of 372 children were included in this study. Compared with non-sensitized children at 6months of age, children with low levels of allergen specific IgE (0.1-0.34kU/L) to food allergens, especially to egg, at 6months of age were associated with development of sensitization to aeroallergens at 5years of age (10/14 [71%] vs 39/250 [15%]). In addition, children with low levels to egg or milk at 6 months were more often sensitized to the respective allergen at 1 year of age and, regarding low levels to egg, also to the development of eczema (6/18 [33%] vs 29/292 [10%]). Conclusion & Clinical RelevanceIgE antibody concentrations in the interval 0.1-0.34kU/L to food allergens in infancy seem to increase the probability of sensitization to aeroallergens and, regarding low levels to egg, also of eczema during early childhood. Thus, IgE levels during the first year of life, although below 0.35kU/L, can provide additional allergy-related prognostic information.