Utility of Ratio of specific IgE/total IgE in Oral Immunotherapy for Food Allergy

Abstract

Oral immunotherapy is currently under investigation for food allergy desensitization. Predictive tests for adverse reaction during food OIT are limited, and would be of great value. In this study, we sought to describe associations between adverse reactions to food OIT, specific IgE alone, and the ratio of specific IgE/total IgE. Medical records of 20 children undergoing food OIT at an academic allergy clinic were reviewed for IgE serology and concomitant OIT outcomes, which were analyzed using descriptive statistics and receiver operator characteristics curves. Half (55%) of children who underwent food OIT had an adverse reaction. Compared to children without adverse reactions during OIT, the ratios of s-IgE/t-IgE for children with adverse reactions were significantly higher (reaction 3.1% vs no reaction 0.7%; p=0.0001). Specific IgE for children with adverse reactions were also higher than those without reactions (reaction 5.0kU/L vs no reaction 2.2kU/L; p=0.013). Receiver operator characteristic curves showed that the ratio (s-IgE/t-IgE) is more accurate than s-IgE alone in predicting adverse reactions in OIT (AUC for Ratio 0.71 > AUC for sIgE alone 0.68), though not statistically significant. Ratio (s-IgE/t-IgE) cut-off of 0.5% provided 91% sensitivity and 75% negative predictive value for an adverse reaction during food OIT. The ratio of s-IgE/t-IgE might be useful in identifying children most likely to tolerate food OIT without adverse reactions. Larger studies are warranted to determine whether the ratio of s-IgE/t-IgE offers an advantage over s-IgE alone in predicting successful food OIT.