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Feb 18: Identification of unique antibody characteristics may result in fewer food challenges

Research into unique antibody characteristics forms the basis for the development of improved, minimally invasive food allergy diagnostics. Such developments are expected to lead to less burden for the patient in the future, because fewer drastic food challenge tests will be required. This was concluded by Anna Ehlers who obtained her PhD degree at Utrecht University on February 18, 2021.

In patients with suspected food allergies accurate diagnosis is important to avoid unnecessary dietary restrictions. Measuring antibodies in the blood, in the case of allergy specific IgE (sIgE), is a commonly used method to determine whether a patient's immune system is hypersensitive to a protein (allergen) contained in food components. Since sIgE measurements can produce "false negative" (negative test result despite allergy) and "false positive" (positive test result despite tolerance) test results, the incriminating food challenge is still the gold standard for food allergy diagnosis. To avoid these false negative and false positive sIgE test results, Anna Ehlers (Department of Dermatology and Allergology and Center for Translational Immunology, UMC Utrecht) studied characteristics of patients' IgE antibodies.

Unique allergen characteristics

In her research, Anna Ehlers reported that false negative test results can be reduced by identifying responsible allergens that are not yet available for current sIgE measurements. Moreover, with regard to macadamia nut allergy, a new group of allergens (viciline-like peptides) was identified that is mainly recognized by sIgE of patients with severe complaints. Measurement of sIgE against these new allergens may be helpful in identifying patients with severe macadamia nut allergy.

She also found that false positive test results can be reduced by identifying specific allergen binding sites that are recognized only by sIgE of allergic patients. SIgE binding to binding sites of the hen’s egg allergen Gal d 1 was able to distinguish between hen’s egg allergic and tolerant adults. In addition to binding characteristics, antibody differences at the DNA level showed the potential to distinguish between peanut allergic and peanut-tolerant patients in the future, something that cannot be achieved by measuring sIgE.

Fewer food challenges

Anna Ehlers concluded: “This research into unique antibody characteristics forms the basis for the development of improved, minimally invasive food allergy diagnostics. Such developments is expected to result in less burden for the patient in the future, because fewer incriminating food challenge tests will be required.”

Food allergy

A food allergy is an abnormal immune response to food. The symptoms of an allergic reaction may range from mild to severe and may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. A systemic and severe reaction is known as anaphylaxis. Common foods involved include cow's milk, peanuts, hen’s egg, shellfish, fish, tree nuts, soy, wheat and fruit. The overall prevalence of food allergy in the European population is approximately 3 percent.

PhD defense

Anna Ehlers (1990, Itzehoe, Germany) defended her PhD thesis on February 18, 2021 at Utrecht University. The title of her thesis was “Improvement of in vitro food allergy diagnostics by identifying unique antibody traits”. Supervisor was prof. dr. André Knulst (Department of Dermatology and Allergology, UMC Utrecht) and co-supervisor was dr. Henny Otten (Center for Translational Immunology, UMC Utrecht).