Tri a 37, a new wheat allergen for diagnosis of severe wheat food allergy

Published Online: July 1, 2013

Wheat is an important food-allergen source which, upon ingestion by sensitized patients, can give rise to severe allergic reactions. The diagnosis of wheat allergy is difficult because blood tests performed with wheat allergen extracts often give positive tests results in patients who can eat wheat without experiencing allergic symptoms. One reason for such “false positive” blood test results is that wheat allergen extracts, besides highly allergenic proteins, also contain components which react with IgE antibodies in the blood, but do not induce severe allergic reactions. Researchers are, therefore, interested in isolating and characterizing purified wheat allergens.  These can be used to improve blood tests for diagnosis of wheat food allergy in order to reduce the necessity for provocation tests, which may induce severe reactions in patients.

In a recent Letter to the editor in The Journal of Allergy and Clinical Immunology, Pahr et al. have isolated a new wheat allergen. They have identified this allergen, Tri a 37, as a plant defense-protein by analysis of its sequence and structure. The function of Tri a 37 as a plant-defense protein is expressed in large amounts in wheat seeds, and its stability against heat and digestion explain why this protein can act as a potent allergen in wheat. The authors found that those patients who contained IgE antibodies in their blood against Tri a 37 had a four-fold increased risk of reacting with severe allergic symptoms upon wheat ingestions. Tri a 37 may, therefore, be used as an important allergen component in blood tests for the reliable identification of wheat-food allergic patients. Component-resolved tests containing individual and clinically well characterized allergen molecules should improve blood testing for wheat-food allergy and replace poorly defined wheat allergen extracts in the near future.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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