THE VALUE OF SPECIFIC IGG4 DETERMINATION IN CHILDHOOD ALLERGY TO EGG IN RELATION TO SPECIFIC IGE AND THE PROVOCATION TEST

The value of IgG4 determination in food allergy shows conflicting resu lts in the medical literature. Our pediatric study was carried out in two phases. The first compared the percentage of detection and agreeme nt of specific IgE (RAST) and IgG4 (FAST) for egg white and egg yolk i n 104 patients with possible hypersensitivity to egg and positive skin tests. The second, in 22 new patients, compared IgG4 determination wi th the oral provocation test (OPT; the diagnostic ''gold standard''). In the first phase, the percentage of positive cases for both antibodi es was almost identical, but little agreement was observed between the m. In the second phase, the sensitivity, specificity and agreement wit h the OPT were higher for IgE than for IgG4. Thus, we conclude that Ig G4 levels may be high in food allergy, but their detection seems to ha ve little diagnostic value in allergy to egg proteins in children.