Utility of Gal d 1-Specific IgE Levels in Predicting Reactivity to Boiled Egg in Chinese Children

Abstract

<b><i>Background:</i></b> Many researchers have reported predicting the outcome of oral food challenges (OFCs) on the basis of specific IgE (sIgE) levels. However, the clinical usefulness of the determination of IgE antibodies to egg allergen components in Chinese children with suspected boiled egg allergy is not well studied. <b><i>Objective:</i></b> Our objective was to assess the diagnostic performance of sIgE to egg white and Gal d 1, 2, 3, and 5 based on the open challenge outcome for boiled egg. <b><i>Methods:</i></b> A total of 48 child patients with a suspect of boiled egg allergy were included. Serum egg white and Gal d 1, 2, 3, and 5 sIgE were measured by ImmunoCAP. Diagnostic value was assessed by area under the receiver operating characteristic curves (AUC). <b><i>Results:</i></b> Using the OFC results as the reference parameter, Gal d 1 sIgE had the highest AUC (0.84) compared with egg white (0.77) and other investigated components (ranging from 0.51 to 0.71). The clinical sensitivity and specificity for the sIgE to Gal d 1 at optimal cutoff (6.15 kU<sub>A</sub>/L) were 73.7% and 96.7%, respectively. Sensitization to Gal d 1 with a cutoff value of >7.48 kU<sub>A</sub>/L indicated a 90% probability of positive challenge. <b><i>Conclusion:</i></b> Quantitative measurements of Gal d 1 sIgE antibodies using ImmunoCAP are useful in the management of boiled egg allergy in Chinese children.