A new research paper published by team from the University of Bern and Bern University Hospital in Switzerland showcases the accuracy of a new test which could improve the diagnosis of food allergies.
The article, recently published in the European Journal for Allergy and Clinical Immunology (Allergy) details how the effectiveness of the test was investigated on samples from children and adolescents with confirmed peanut allergy and a healthy control group in a clinical study in collaboration with partners from the Hospital for Sick Kids in Toronto, Canada. They were able to show that the new test has a higher diagnostic accuracy than existing methods.
A team of researchers led by Professor Dr Alexander Eggel from the Department for BioMedical Research (DBMR) at the University of Bern and the Department of Rheumatology and Immunology, Bern University Hospital, and Professor Dr Thomas Kaufmann from the Institute of Pharmacology at the University of Bern, developed an alternative test in 2022. It mimics the allergic reaction in a test tube and thus offers an attractive alternative to standard tests.
The Hoxb8 MAT test uses Hoxb8 mast cells cultured in a laboratory to mimic an allergic reaction. As this reaction occurs in a test tube, the new diagnostic offers an alternative to current tests. The oral food challenge test, in which people consume the allergen (such as peanut extract) under supervision to test the allergic reaction, is still considered the gold standard in diagnosis. However, the method is complex and carries health risks. The allergen skin prick test and blood test are often not very accurate, which can lead to misdiagnoses and unnecessary food avoidance.
“The most common food allergies are type I allergies. They develop when the body produces immunoglobulin E (IgE) antibodies in response to the presence of allergens,” explains Alexander Eggel. These antibodies bind to specific receptors on the mast cells, which are immune cells that play an important role in allergic reactions and inflammation. They are mainly located in the tissue, for example, in the intestinal mucosa, and are prepared for and sensitised to the allergen by binding to the antibodies. Upon renewed contact with the allergen, it binds directly to the mast cells loaded with antibodies, activating them and triggering an allergic reaction. “In the Hoxb8 mast cell activation test (Hoxb8 MAT), which we developed, mast cells grown in the laboratory are brought into contact with blood serum from allergic patients. The mast cells bind the IgE antibodies from the serum and are sensitised by them. We can then stimulate the mast cells with different amounts of the allergens to be tested,” says Eggel. Quantifying the activated mast cells suggests how allergic a patient is to the allergen tested without needing to consume the food.
The study used serum samples from a total of 112 children and adolescents who had already participated in a study in Canada and for whom clear diagnostic data on their peanut allergy status were available. The mast cells cultured in the laboratory were sensitised with their serum and then stimulated with peanut extract. “The cell-based test was easy to carry out and worked perfectly. All samples were measured within two days, which was very fast,” says Thomas Kaufmann. The results showed that a large number of sera from allergic patients exhibited allergen dose-dependent activation, while almost all samples from the non-allergic control subjects did not activate the mast cells. “An exceptionally high diagnostic accuracy of 95% could be calculated from these data,” Eggel adds.
- Bachmeier-Zbären N, Celik A, van Brummelen R, et al. Clinical utility analysis of the Hoxb8 mast cell activation test for the diagnosis of peanut allergy. Allergy. 2024 Sep 28. doi: 10.1111/all.16341. Online ahead of print.