Not all milk allergies are created alike. Some folks get hives from caseins, while others wheeze after eating whey proteins. Nine of milk’s more than 25 proteins show a tendency to trigger allergic reactions, so traditional diagnostics generally screen just those nine. Now Swiss researchers offer a diagnostic that can pinpoint not only the troublesome nine, but also any unexpected allergens (Anal. Chem. 2014, DOI: 10.1021/ac500525n). The method offers a comprehensive allergy diagnosis, plus a promising way to track down entirely new allergenic proteins in foods and the environment.
To get to the source of a milk allergy, physicians often order a component-resolved diagnostic, an assay that determines whether known milk allergens bind to a patient’s immunoglobulin E (IgE) antibodies. These antibodies are the ones that can spark allergic reactions.
In the new test, Hubert H. Girault and Natalia Gasilova of the Swiss Federal Institute of Technology, Lausanne, made magnetic beads dotted with antibodies that bind all IgE antibodies in an allergic patient’s blood serum. The researchers then chemically cross-link the patient’s IgE antibodies to the beads. When they expose these personalized beads to milk, the patient’s own antibodies bind his or her particular allergens within the milk.
With matrix-assisted laser desorption/ionization mass spectrometry, the researchers then identify all bound allergens. This allows researchers to predict the structure of even unfamiliar allergens.
The scientists demonstrated the method by identifying one patient’s four milk allergens. Now they are adapting the technique to pollen, where they hope to discover novel allergenic proteins.