Allergen-specific immunoglobulin E antibodies in wheezing infants: the risk for asthma in later childhood.

OBJECTIVE: To evaluate whether the measurement of specific immunoglobulin E (IgE) antibodies to food and/or inhalant allergens in infants who are hospitalized for wheezing can be used to predict later asthma.
METHODS: Eighty-two children who were hospitalized for wheezing at <2 years of age were followed prospectively until early school age. The baseline data and the characteristics of infancy had been collected at enrollment. At school age, the children were evaluated for asthma and allergic manifestations, including skin prick tests to common inhalant allergens. Frozen serum samples obtained during the index episode of wheezing were available for 80 children for determination of food and inhalant allergen-specific serum IgE antibodies by fluoroenzyme-immunometric assay, UniCAP, applying the Phadiatop Combi allergen panel.
RESULTS: Asthma was present in 32 (40%) children at school age. Food-specific IgE antibodies of >or=0.35 kU/L were found in 37 (46%) wheezing infants, but only specific IgE to wheat and to egg white at the level of >or=0.35 kU/L were significantly associated with later asthma. In regard to specific IgE to the mixture of food allergens, the cutoff level of >or=0.70 proved to be significant. Inhalant allergen-specific IgE of >or=0.35 kU/L was found only in 14 cases (18%), but when present, it was significantly predictive of asthma. Elevated levels of specific IgE antibodies to food or inhalant allergens were significantly associated with allergic rhinitis and skin-test reactivity at school age.
CONCLUSIONS: When present in wheezing infants, specific IgE of >or=0.35 kU/L to wheat, egg white, or inhalant allergens are predictive of later childhood asthma. Consequently, detection of those specific IgE antibodies in wheezing infants may facilitate the early diagnosis of asthma, especially in cases with no clinically evident atopic manifestations.