Development and Early Evaluation of a Streamlined, Miniaturized and Multi-Allergen Basophil Activation Test Platform

While the basophil activation test (BAT) holds increasing potential in food allergy diagnosis, major challenges impede its widespread use in clinical settings.

To assess the feasibility and provide proof-of-concept for a newly developed 96-well plate-based, streamlined, miniaturized and multi-allergen basophil activation test (SMMABAT), using dry, room temperature-stable, ready-to-use reagents. This objective was pursued through a pilot study implemented across three US food allergy clinical centers.

Whole blood samples from 81 participants (1-36 years of age) were tested with prototypes that assessed 87 conditions with <2 mL blood. In addition to negative and positive controls, samples were tested against 11 foods at 7 concentrations and 7 individual components at 1000 ng/mL.

891 dose responses were generated. Significant correlations (p<0.0001) were observed between SMMABAT reactivities and allergic (n=245) or tolerant (n=465) clinical statuses. Across 11 allergens (including nuts, tree nuts, milk and egg), most informative doses (1-1000 ng/mL) yielded 97% specificity (1 ng/mL) and 82% sensitivity (1000 ng/mL). For a subset of 322 clinical statuses with available IgE levels, specific IgE (sIgEs) to raw extracts exhibited 97.1% sensitivity but 39.7% specificity. By combining SMMABAT and sIgEs with optimized thresholds, a significant complementarity was demonstrated, yielding 98% sensitivity, 85.3% specificity, 90.6% PPV, and 96.7% NPV. Allergic patients undergoing oral immunotherapy (OIT) exhibited significantly lower SMMABAT reactivities (p<0.0001) than untreated allergic patients, despite similar sIgE levels.

SMMABAT can be implemented in clinical research to complement sIgE. It can thus contribute to enhanced management of allergic patients, especially those at risk of multi-food allergies.