B) Methods: This study included 196 children who visited Ajou University Hospital for suspicious food allergy. The subjects were divided into two groups; wheat allergy (WA) group and non-wheat allergy (Non-WA) group. The subjects with wheat allergy were further divided into two groups according to their symptoms: wheat anaphylaxis (WAAna) group and non-wheat anaphylaxis (WANon-Ana) group. The serum concentrations of total IgE and specific IgE antibodies to wheat, gluten and ω-5 gliadin were measured. The diagnostic values of each specific antibody were analyzed and compared using the Mann-Whitney test and receiver operating characteristic curves.
C) Results: The median values of specific IgE antibodies to wheat, gluten and ω-5 gliadin were significantly higher in WA compared to those in Non-WA, and the optimal cutoff points were 0.90 kUA/L, 0.43 kUA/L and 0.19 kUA/L respectively. The positive decision points (specificity of 95%) of specific IgE antibodies to wheat, gluten and ω-5 gliadin were 3.12 kUA/L, 2.61 kUA/L and 0.21 kUA/L respectively, and the accuracies at these levels were 91.8%, 92.9% and 93.4% correspondingly. The combination of specific IgE antibodies to wheat and ω-5 gliadin resulted in the highest accuracy of 93.9% in diagnosing wheat allergy. In differentiating WAAna from WANon-Ana,, only the specific IgE antibodies to ω-5 gliadin showed significant difference (p=0.013) at the optimal cutoff point of 1.56 kUA/L.
D) Conclusion: Our results show that the individual levels of specific IgE antibodies to wheat, gluten or ω-5 gliadin had considerably high accuracies in diagnosing wheat allergy, and specific IgE antibody to ω-5 gliadin was particularly useful in predicting wheat anaphylaxis.