High Diagnostic Sensitivity and Specificity By Analysis of IgE to Different Types of Gliadins When Evaluating Wheat Allergy in Children

Rationale: Wheat sensitization is more common than wheat allergy and as a result the specificity of the IgE antibody (IgE-ab) wheat test is poor. More specific tests, that correctly identify wheat allergic individuals, are needed. Allergens extracted from the gluten fraction of wheat, especially ω5-gliadin, have proven useful in several recent studies. In this study we have evaluated the diagnostic performance of three different types of gliadins in a group of wheat allergic children.

Methods: Thirty-one children diagnosed with wheat allergy by either a positive oral wheat challenge or a convincing recent history, and 72 grass-pollen allergic children currently eating wheat (controls) were recruited for the study.  Sera were analyzed for IgE-ab to wheat, recombinant ω5-gliadin, two recombinant γ-gliadins and a native gliadin preparation containing α-, β-, γ-, and ω-gliadins using a cut-off of 0.35 kU_A/l.

Results: The wheat test had a sensitivity of 100% but a lower specificity of 40%. Native gliadin had a similar sensitivity (94%) but better specificity (96%). Sensitivities were 81% for the two tests measuring IgE-ab to γ-gliadin and 68% for the ω5-gliadin test. Specificities for these tests ranged from 94 to 97%.

Conclusions: Measurements of IgE-ab to gliadins are useful tools to support the identification of wheat food allergic children. All four gliadin tests evaluated had specificities of more than 94%. The test with native gliadins had the best sensitivity followed by the two γ-gliadin tests and the ω5-gliadin test.