Change in exhaled nitric oxide during peanut challenge is related to severity of reaction

Elizabeth Percival,Joerg Mattes,Adam Collison,Mark Mcevoy,Rani Bhatia,Kahn Preece

doi:10.1186/s13223-020-00464-8

Abstract

BackgroundPeanut allergy affects 3% of Australian children and has a higher risk of anaphylaxis than most food allergies. Predicting who is likely to develop anaphylaxis is still an inexact science. The fraction of exhaled nitric oxide (FeNO) shows promise as a biomarker involved in peanut allergy, as nitric oxide plays a role in inhibiting mast cell degranulation which is relevant in anaphylaxis, where mast cell degranulation plays a mediator role. The aim of this study was to assess the change in FeNO in children during peanut challenge.MethodsThirty-six children aged from 5 to 17 years were recruited for open-labelled peanut challenge. Participants had skin prick test to peanut performed, and serum collected for Ara h2 specific IgE and peanut specific IgE. FeNO was measured by portable device (NIOX VERO) prior to and throughout the peanut challenge.ResultsWhen grouped according to reaction type at peanut challenge (anaphylaxis, clinical allergy not anaphylaxis and tolerant), there were significant differences in the mean change in FeNO measurement between the anaphylaxis group and the clinical allergy, not anaphylaxis group (p = 0.005), and between the anaphylaxis group and tolerant group (p < 0.0001).ConclusionsFeNO decreased more significantly in those who subsequently developed anaphylaxis than in those with clinical allergy, not anaphylaxis or negative peanut challenge (tolerance). As a bedside test that can be used in children, it has potential for further research into mechanisms of anaphylaxis in food allergy and potentially assists in predicting an imminent anaphylactic reaction in some patients.Trial registration ClinicalTrials.gov: PEAnut Anaphylaxis Predictors (PEAAP) NCT02424136.

Highlights

Peanut allergy affects 3% of Australian children and has a higher risk of anaphylaxis than most food allergies
Unlike other food allergies such as dairy and egg which often resolve by school age [3,4,5,6,7,8], peanut allergy tends to persist with tolerance developing in approximately 20% of children [9], but the mechanisms involved are not yet apparent [10]
Two children were unable to undergo peanut challenge: one child was unwell on the day of the challenge and was unable to be rescheduled during the study timeframe; a second child’s peanut skin prick testing (SPT) was > 10 mm on the day of challenge, so not challenged as per study exclusion criteria

Summary

Introduction

Peanut allergy affects 3% of Australian children and has a higher risk of anaphylaxis than most food allergies. The fraction of exhaled nitric oxide (FeNO) shows promise as a biomarker involved in peanut allergy, as nitric oxide plays a role in inhibiting mast cell degranulation which is relevant in anaphylaxis, where mast cell degranulation plays a mediator role. Peanut allergy is one of the most common food allergies, reported to affect up to 3% of Australian children in a 2011 population-based study [1]. Unlike other food allergies such as dairy and egg which often resolve by school age [3,4,5,6,7,8], peanut allergy tends to persist with tolerance developing in approximately 20% of children [9], but the mechanisms involved are not yet apparent [10].

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