Biomarkers can help identify allergic patients at risk of severe reactions to peanut

Published online: April 17, 2020

Peanut allergy can cause severe life-threatening allergic reactions. Patients at risk of developing severe symptoms from accidental exposure to peanut or at risk of reacting to small amounts of the allergen deserve particular attention and individualized management and follow up.

In a study recently published in The Journal of Allergy and Clinical Immunology (JACI), Alexandra Santos et al analysed the utility of various biomarkers to predict the outcome of controlled exposure to peanut in a medically supervised environment, the oral food challenge (OFC). Participants in the Learning Early About Peanut Allergy (LEAP) study underwent OFC to peanut at the end of the study to determine whether or not they had developed peanut allergy. A similar procedure was undertaken by participants in the LEAP-On and the Peanut Allergy and Sensitization (PAS) studies. The severity of allergic reactions and the total amount of peanut ingested during the OFC was determined in all three studies. On the same day of the OFC, study participants underwent skin prick testing (SPT) and blood collection for specific IgE testing (sIgE) and basophil activation test (BAT) to peanut. The results of these biomarkers were compared with the outcomes of OFC.

The BAT, which had been developed and validated in a previous study, confirmed its diagnostic utility in confirming the diagnosis of peanut allergy. The BAT was the best predictor of severity of allergic reactions, closely followed by Ara h 2-specific IgE and SPT. To identify patients reacting to less than 100mg of peanut protein, BAT and SPT were the best predictors. A multivariate model combining multiple tests was better able to predict severity and dose at which patients reacted to peanut during OFC than the individual biomarkers. Such combinations were used to build diagrams for clinical practice, called “nomograms”, which clinicians can use to determine, based on the results of different biomarkers, the likelihood of an individual patient to have a severe reaction or to react to a low dose of peanut.

In summary, peanut allergic patients at risk of severe reactions and of reacting to trace amounts of peanut deserve an individualised treatment plan, education and follow up. A combination of biomarkers can identify the high-risk patients, thus improving the management of peanut allergy.

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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