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

BACKGROUND

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

METHODS

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.

RESULTS

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.

CONCLUSIONS

We have demonstrated that the egg white-specific serum IgE/IgG4 ratio is important for predicting reactivity to egg during food challenges.