Natural history of immediate-type hen's egg allergy in Japanese children.

BACKGROUND: Hen's egg (HE) allergy develops during infancy. We investigated tolerance acquisition in Japanese children allergic to HE aging <6 years. METHODS: In this retrospective study, 226 children born in 2005 with a history of immediate-type HE allergy underwent an oral food challenge (OFC). Tolerance was defined as no reaction to an OFC with half of whole heated HE or accidental HE consumption at home. Participants were divided into three groups based on age at tolerance acquisition: group I (<3 years) (n = 66), group II (3-6 years) (n = 98), and group III (prolonged allergic groups) (n = 62). RESULTS: Tolerance acquisition occurred in 30% (66/226) by 3 years of age, 59% (133/226) by 5 years of age, and 73% (164/226) at 6 years of age. At 3 years, incidences of allergy-related complications (bronchial asthma, p = 0.02; atopic dermatitis, p = 0.04) were higher in the group III than in the group I. Anaphylaxis to any food occurred more frequently in the group III than in the group I (p = 0.03); anaphylaxis to HE was more common in the group III (p = 0.04). Egg white (EW)- and ovomucoid (OM)-specific immunoglobulin E (IgE) levels were higher in the group III than in the group I (p < 0.05). CONCLUSIONS: The group III experienced HE-related anaphylaxis and complications more frequently and exhibited sustained, high EW- and OM-specific IgE levels.

The Combination of Binding Avidity of Ovomucoid-Specific IgE Antibody and Specific IgG4 Antibody Can Predict Positive Outcomes of Oral Food Challenges during Stepwise Slow Oral Immunotherapy in Children with Hen's Egg Allergy.

To increase the prediction accuracy of positive oral food challenge (OFC) outcomes during stepwise slow oral immunotherapy (SS-OIT) in children with a hen's egg (HE) allergy, we evaluated the predictive value of the combination of antigen-specific IgE (sIgE) with antigen binding avidity and sIgG4 values. Sixty-three children with HE allergy undergoing SS-OIT were subjected to repeated OFCs with HE. We measured the ovomucoid (OVM)-sIgE by ImmunoCAP or densely carboxylated protein (DCP) microarray, sIgG4 by DCP microarray, and the binding avidity of OVM-sIgE defined as the level of 1/IC50 (nM) measured by competitive binding inhibition assays. The OFC was positive in 37 (59%) patients undergoing SS-OIT. Significant differences in DCP-OVM-sIgE, CAP-OVM-sIgE, I/IC50, DCP-OVM-sIgG4, the multiplication products of DCP-OVM-sIgE, and the binding avidity of DCP-OVM-sIgE (DCP-OVM-sIgE/IC50) and DCP-OVM-sIgE/sIgG4 were compared between the negative and positive groups (p < 0.01). Among them, the variable with the greatest area under the receiver operating characteristic curve was DCP-OVM-sIgE/IC50 (0.84), followed by DCP-OVM-sIgE/sIgG4 (0.81). DCP-OVM-sIgE/IC50 and DCP-OVM-sIgE/sIgG4 are potentially useful markers for the prediction of positive OFCs during HE-SS-OIT and may allow proper evaluation of the current allergic status in the healing process during HE-SS-OIT.