The Basophil Activation Tests Accurately Predicts Clinical Food Allergy
Sunday, March 5, 2017
Exhibit Hall B2 (Georgia World Congress Center, Building B)
Bruce J. Lanser, MD, Hannah Giclas, MS, Ashley Kohlhepp, RN, BSN, Patricia Merkel, MS, Vijaya Knight, MD, PhD, D(ABMLI)
Rationale: Current testing methods (skin prick testing (SPT) and specific IgE measurement (sIgE)) demonstrate food sensitization, but cannot diagnose clinically relevant IgE mediated food allergy, without uncertainty. Food allergy is increasing in prevalence, leading to more testing and overly restrictive diets. The basophil activation test (BAT), an ex-vivo assessment of allergic response, may offer superior correlation with clinical diagnosis of food allergy. With IRB approval, we assessed the performance of the BAT in children undergoing evaluation for food allergy.

Methods: Whole blood was incubated with PBS (negative control), anti-FceR1 antibody (positive control), and allergens (milk, egg, wheat, soy, peanut and tree nuts, titrated). After 15 min at 37°C, samples were placed on ice to halt further activation. Cells were stained for CD45, IgE and CD203c, and analyzed by flow cytometry. Basophil activation (fold increase of CD203c expression over baseline) was measured. Tolerance or allergy to a food was determined by convincing clinical history or observed oral food challenge (OFC) and correlated with BAT, sIgE and SPT.

Results: 11 patients underwent the BAT. Of these, 30 (90.9%) foods were correctly identified as having a negative BAT correlating to clinical tolerance. 1 (3%) was incorrectly identified as having a negative BAT to peanut, but positive reaction on OFC. 2 (6%) foods (milk and peanut) in 1 patient were incorrectly identified as having a positive BAT, but passed OFCs. 

Conclusions: The BAT accurately predicts clinical food allergy, may offer the opportunity to perform fewer OFCs, and could replace other testing methods for IgE-mediated food allergy.