Validating the predicted peanut allergen threshold in children

The eliciting doses of allergenic foods can be defined by the distribution of threshold doses for individuals within a specific population. ED05 is the dose that elicits a reaction in 5% of allergic subjects. Using a novel single dose challenge, an international multi-centre trial has sought to validate the predicted peanut ED05, which is 1.5 mg of peanut protein or 6 mg whole peanut (for reference, one peanut contains approximately 250 mg of peanut protein).

Close to 400 children with peanut allergy, recruited at three different centers, participated in the trial. Following a single dose of 1.6mg peanut protein, 65% of the participants reported no reaction; 18% reported a subjective reaction with no objective findings; and 15% experienced some signs that were only mild and transient. The single dose peanut protein elicited an ‘objective response’ in fewer than the predicted 5% of peanut-allergic subjects, with only 2% (8 participants) experiencing symptoms that were deemed to be an allergic response. Four of these children were treated with oral antihistamines and none required treatment with adrenalin.

Food allergy related quality of life was also assessed during the trial and all participants reported improved scores from baseline to 1 month post challenge regardless of their challenge outcome.

While this single-dose approach has not yet been validated for risk assessment of individual patients, the authors conclude it is clinically safe and patient-acceptable.

Authors include Dr Katrina Allen, Royal Children’s Hospital, Melbourne, and Dr Joe Baumert and Dr Steve Taylor, FARRP from the VITAL Scientific Expert Panel, several of whom will be presenting at the 2nd Food Allergen Management Symposium (FAMS2017) in Sydney.

Reference: Hourihane et al. 2017 Journal of Allergy & Clinical Immunology. pii: S0091-6749(17)30324-X. DOI: 10.1016/j.jaci.2017.01.030.