W107 - Evaluating Variability in Protein Content of At-home Peanut Allergy OIT Doses

Abstract Text:

Background: Peanut oral immunotherapy (OIT) uses controlled doses of peanut protein to build tolerance. At-home doses are prepared by mixing peanut powder (PB2) into applesauce. Measuring spoons are only available down to 1/64 tsp, but smaller doses are obtained by diluting 1/64 tsp PB2 (~16 mg protein) in applesauce. Currently, doses of ~4 mg protein (1/256 tsp; 1:4 dilution) are used for OIT. Our study aimed to evaluate variability in protein content across dilutions and assess whether smaller doses are feasible using this method.

Methods: PB2-applesauce dilutions were prepared at 1:1, 1:2, 1:4, or 1:8 (~16, ~8, ~4, or ~2 mg protein respectively). Protein content was analyzed via SDS-PAGE electrophoresis and quantified using ImageJ.

Results: Variability was assessed by calculating the coefficient of variance for total protein and the major peanut allergen, Ara h2. For total protein, the CVs were 10.22% (1:1), 13.28% (1:2), 34.86% (1:4), and 51.44% (1:8). When analyzing the Ara h2 protein band alone, variability was 16.38% (1:1), 26.52% (1:2), 15.90% (1:4), and 29.28% (1:8).

Conclusion: These findings suggest that current at-home OIT doses may require further evaluation for consistent protein delivery. With dilutions using this technique, variance is inversely proportional to concentration, suggesting that patients sensitive to low doses could be at risk of reactions. However, lower variability of the major allergen, Ara h2, calls into question the clinical significance and may help to account for a low rate of adverse reactions observed to date.