Detection of Sensitization Profiles with Cellular In Vitro Tests in Wheat Allergy Dependent on Augmentation Factors (WALDA).

Wheat allergy dependent on augmentation factors (WALDA) is the most common gluten allergy in adults. IgE-mediated sensitizations are directed towards ω5-gliadin but also to other wheat allergens. The value of the different in vitro cellular tests, namely the basophil activation test (BAT) and the active (aBHRA) and passive basophil histamine-release assays (pBHRA), in the detection of sensitization profiles beyond ω5-gliadin has not been compared. Therefore, 13 patients with challenge-confirmed, ω5-gliadin-positive WALDA and 11 healthy controls were enrolled. Specific IgE (sIgE), skin prick tests, BATs, aBHRA, and pBHRA were performed with allergen test solutions derived from wheat and other cereals, and results were analyzed and compared. This study reveals a distinct and highly individual reactivity of ω5-gliadin-positive WALDA patients to a range of wheat allergens beyond ω5-gliadin in cellular in vitro tests and SPT. In the BAT, for all tested allergens (gluten, high-molecular-weight glutenin subunits, α-amylase/trypsin inhibitors (ATIs), alcohol-free wheat beer, hydrolyzed wheat proteins (HWPs), rye gluten and secalins), basophil activation in patients was significantly higher than in controls (p = 0.004-p < 0.001). Similarly, significant histamine release was detected in the aBHRA for all test substances, exceeding the cut-off of 10 ng/mL in all tested allergens in 50% of patients. The dependency of tests on sIgE levels against ω5-gliadin differed; in the pBHRA, histamine release to any test substances could only be detected in patients with sIgE against ω5-gliadin ≥ 7.7 kU/L, whereas aBHRA also showed high reactivity in less sensitized patients. In most patients, reactivity to HWPs, ATIs, and rye allergens was observed. Additionally, alcohol-free wheat beer was first described as a promising test substance in ω5-gliadin-positive WALDA. Thus, BAT and aBHRA are valuable tools for the identification of sensitization profiles in WALDA.

Wheat-dependent exercise-induced anaphylaxis: subtypes, diagnosis, and management.

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is an IgE-mediated food allergy with allergic symptoms ranging from intermittent urticaria to severe anaphylaxis that occurs when wheat ingestion is combined with augmenting cofactors such as exercise, non-steroidal anti-inflammatory drugs, or alcohol. In most cases, patients are identified by sensitization to ω5-gliadins in the gluten fraction of wheat. ω5-gliadin-negative subtypes of WDEIA are often difficult to diagnose and may be caused by Tri a 14 (wheat lipid transfer protein), after percutaneous sensitization with hydrolyzed wheat proteins, or, in rare cases, by cross-reactivity to grass pollen. Diagnosis is established based on the patients' history in combination with serum IgE profile, skin testing, basophil activation tests, and challenge tests with cofactors. Individual dietary counselling remains the central pillar in the management of WDEIA patients. A completely wheat-free diet is a possible option. However, this appears to promote tolerance less than continued regular consumption of gluten-containing cereals in the absence of cofactors. All patients should have an emergency set for self-treatment including an adrenaline autoinjector and receive adequate instruction. More data are needed on sublingual immunotherapy for WDEIA, a potentially promising therapeutic prospect. This article provides an overview of current knowledge on the diagnosis and management of WDEIA including an optimized challenge protocol using wheat gluten and cofactors.