Predictive value of IgE/IgG4 antibody ratio in children with egg allergy

Abstract

The aim of this study was to investigate the role of specific IgG₄ antibodies to hen’s egg white and determine their utility as a marker for the outcome of oral challenge test in children sensitized to hen’s egg The hen’s egg oral food challenge test was performed in 105 sensitized children without atopic dermatitis, and the titers of egg white-specific immunoglobulin G₄ (IgG₄) and immunoglobulin E (IgE) antibodies were measured. To set the cut-off values of IgG₄, IgE, and the IgE/IgG₄ ratio for predicting positive results in oral challenges, receiver operating characteristic curves were plotted and the area under the curves (AUC) were calculated. Sixty-four of 105 oral challenges with whole eggs were assessed as positive. The AUC for IgE, IgG₄, and IgE/IgG₄ for the prediction of positive results were 0.609, 0.724, and 0.847, respectively. Thus, the IgE/IgG₄ ratio generated significantly higher specificity, sensitivity, positive predictive value (%), and negative predictive value (%) than the individual IgE and IgG₄. The negative predictive value of the IgE/IgG₄ ratio was 90% at a value of 1. We have demonstrated that the egg white-specific serum IgE/IgG₄ ratio is important for predicting reactivity to egg during food challenges.