Component-Resolved Analyses for Diagnosis of Food Allergies in Infants and Young Children in Southern China

Introduction: Chicken eggs and cow’s milk are two of the most common foods that cause allergic reactions in infants and young children, and there is a lack of precise diagnostic methods to identify the allergic state of these patients. The recently developed food allergen component-resolved diagnosis (CRD) may be a more accurate diagnosis method for food allergies. Methods: One hundred children sensitized to egg white and milk crude extracts and diagnosed with or suspected allergic disease were included. The specific immunoglobulin E (sIgE) (s) of animal food allergen crude extracts (egg yolk, milk, shrimp, crab, cod, beef) and the main components of egg white and milk were tested. The sensitization characteristics, cross-reactivity, and clinical relevance were analyzed. Results: The results of egg white-sensitized patients showed that ovalbumin (Gal d 2) had the highest positive rate of 100%. Compared with other pairwise combinations of egg allergens, the combination of egg white and Gal d 2 had higher diagnostic accuracy, with an AUC of 0.876 (95% CI: 0.801–0.951), a sensitivity of 88.9%, and a specificity of 75.9%. The positive rates of beta-lactoglobulin (Bos d 5) and alpha-lactoglobulin (Bos d 4) in the milk-sensitized children were comparable, 92% and 91%, respectively. The combination of crude milk extract and Bos d 4 had the highest diagnostic accuracy, with an AUC of 0.969 (95% CI: 0.938–0.999), a sensitivity of 100%, and a specificity of 82.7%. Conclusion: Among these subjects, our study found the main allergenic component of egg white was Gal d 2, and the main allergenic components of milk were Bos d 4 and Bos d 5. CRD may help identify egg/milk allergies and non-allergies.