Can measurement of total IgE improve food allergy diagnosis?

Published Online: April 14, 2016
Food allergy can only be diagnosed reliably with a tedious oral food challenge. It has been investigated widely how food-specific E antibodies could be used to predict challenge outcomes. With low or very high levels of food-specific IgE, food allergy is assumed to be rather unlikely or very likely, and challenge testing could be omitted. But it is still unknown whether measuring the total amount of IgE antibodies could further improve the prediction of challenge outcomes.
In a recent report published in The Journal of Allergy & Clinical Immunology (JACI) Grabenhenrich and colleagues analyzed the role of total IgE in predicting peanut and hazelnut challenge outcomes. In a multicenter sample of more than 350 oral food challenges conducted in children, the authors measured total IgE, peanut- or hazelnut-specific IgE and antibodies against four single proteins of either peanut or hazelnut known to play an important role in causing clinical food allergy (i.e., component resolved diagnosis).
Their first approach was to calculate the ratio of food- or protein-specific IgE to total IgE. Assessed by a logistic prediction model, these ratios did not improve the discrimination between allergic and non-allergic children above what can be achieved by using only the food- or protein-specific values directly. From this approach, the authors provided a continuous prediction model, which can be used to estimate the probability for food allergy given a calculated ratio for a single patient. Their second approach was to estimate continuous prediction models for component-specific IgE levels within strata of low, medium or high total IgE. Interestingly, at a given level of component-specific IgE (Ara h 2 for peanut and Cor a 14 for hazelnut allergy), the probability of a diagnosis of food allergy was considerably lower with high levels of total IgE (above 500 kU/l).
The authors discourage clinicians from calculating ratio measures, but support the measurement of total IgE for a stratified prediction of oral food challenge outcomes. They highlight the role of Ara h 2 and Cor a 14 as the best single predictors for peanut and hazelnut allergy, respectively.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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