Clinical utility of Basophil and B-cell biomarkers for monitoring disease activity in food allergy and food oral immunotherapy

As research in the field of food allergy is gaining momentum with new and emerging therapies there is need for both researchers and clinicians to have a better understanding on how to put all this new information into context in clinical care. We are continuously learning from other fields, such as oncology, that a one-shoe-fits all type approaches are becoming the practice of the past and there is need to incorporate markers of disease activity as well as drug selection into clinical care. In the United States, this can happen in two ways; laboratory developed testing and companion diagnostics, generally former leading the path to the later. The findings in this letter is a collaboration between four CLIA/CAP accredited in-office flow cytometry laboratories in Utah, New York and Virginia that are part of very busy food allergy clinics directed by board certified Allergist/Immunologists. The identification of changes in basophils and B cells during oral food immunotherapy are proving to be potentially useful markers in monitoring these patients. We show a high ratio of CD63 to CD203c and CD73 expression on B-cells, compared to healthy non-allergic controls and patients who have outgrown their food allergies. This ratio of basophil surface markers as well as B cell CD73 expression drops as patients are undergoing food-OIT. Quite interestingly, we see a similar low pattern in patients who have non-releaser basophils. Altogether these biomarkers are providing useful and important information monitoring patients and we have validated these assays for clinical use as laboratory developed tests. The Basophil Activation Test is used much more routinely outside the United States, and the powerful correlation it provides to oral food challenge outcomes is making it a very attractive tool. We have just submitted two manuscripts on the validation of the BAT as well as sample stability which is under review elsewhere. We expect more utility of the BAT in the United States in the future. Incorporating biomarkers to clinical care of patients with food allergies will provide to be important in assessing efficacy as well as complications of various therapies as well as monitoring the natural resolution of the food allergies.