Sequential hypoallergenic boiled peanut and roasted peanut oral immunotherapy

Abstract

Oral immunotherapy (OIT) using roasted peanut flour can effectively desensitize peanut-allergic children [1] but is considered not to be ready for clinical practice [2] due to high rates (≥45%) of adverse events (AEs) [3] [4]. This necessitates medically supervised up-dosing in hospital and limits the number of patients that can be treated. In 2001 Beyer et. al proposed that the prevalence of peanut allergy in China was lower than that of the Western world because peanuts consumed in China were boiled, not roasted [5]. They demonstrated that boiling peanuts for 20 minutes reduced IgE binding in vitro when compared to roasted peanut. We have subsequently shown that extended boiling progressively reduced peanut IgE binding to 12.5% at 2 hours and to 5.3% at 12 hours compared to raw peanut while still retaining T cell reactivity [6]. Further, Inhibition ELISAs demonstrated that boiled peanuts have restricted ability (2-h ~70%, 12-h ~50%) to block the binding of patient IgE to raw peanut [6] suggesting boiled peanuts possess an incomplete repertoire of epitopes. This indicates that boiled peanuts alone are unlikely to expose a patient to the full spectrum of peanut epitopes and will therefore require a roasted peanut phase following the initial boiled peanut therapy. We hypothesize that AEs can be reduced by commencing OIT with hypoallergenic boiled peanut. Here we describe a pilot study that aims to characterize the incidence of AEs and successful desensitization in mild/moderate peanut allergic children using hypoallergenic 2-hour boiled peanut prior to roasted peanut OIT. Due to the home-based up-dosing procedure, a cautious approach was adopted which excluded severely allergic children.

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