Abstract
BackgroundEliciting doses (EDs) (eg, ED01 or ED05 values, which are the amounts of allergen expected to cause objective symptoms in 1% and 5% of the population with an allergy, respectively) are increasingly being used to inform allergen labeling and clinical management. These values are generated from food challenge, but the frequency of anaphylaxis in response to these low levels of allergen exposure and their reproducibility are unknown.ObjectiveOur aim was to determine (1) the rate of anaphylaxis in response to low-level peanut exposure and (2) the reproducibility of reaction thresholds (and anaphylaxis) at food challenge.MethodsWe conducted a systematic review and individual participant data meta-analysis of studies that reported at least 50 individuals with peanut allergy reacting to peanut at double-blind, placebo-controlled food challenge (DBPCFC) and were published between January 2010 and September 2020. Risk of bias was assessed by using National Institute for Clinical Excellence methodologic checklists.ResultsA total of 19 studies were included (covering a total of 3151 participants, 534 of whom subsequently underwent further peanut challenge). At individual participant data meta-analysis, 4.5% (95% CI, 1.9% to 10.1%) of individuals reacted to 5 mg or less of peanut protein with anaphylaxis (moderate heterogeneity [I2 = 57%]). Intraindividual thresholds varied by up to 3 logs, although this variation was limited to a half-log change in 71.2% (95% CI, 56.2% to 82.6%) of individuals. In all, 2.4% (95% CI, 1.1% to 5.0%) of patients initially tolerated 5 mg of peanut protein but then reacted to this dose at subsequent challenge (low heterogeneity [I2 = 16%]); none developed anaphylaxis.ConclusionAround 5% of individuals reacting to an ED01 or ED05 level of exposure to peanut might develop anaphylaxis in response to that dose. This equates to 1 and 6 anaphylaxis events per 2500 patients exposed to an ED01 or ED05 dose, respectively, in the broader population of individuals with peanut allergy.
Highlights
Eliciting doses (EDs) are increasingly being used to inform allergen labeling and clinical management
The use of reference doses to inform allergen risk management is increasing; like the use of precautionary allergen labeling, this area is currently unregulated in most countries, in part because of knowledge gaps, which include the risk of anaphylaxis in response to low-level allergen exposure.[8,39]
In this individual participant data (IPD) meta-analysis of threshold and symptom data from more than 3000 DBPCFCs to peanut, we found that approximately 4% to 5% of individuals with an allergy who react to ED01 or ED05 levels of peanut with objective symptoms will experience anaphylaxis
Summary
We conducted a systematic review and individual participant data meta-analysis of studies that reported at least 50 individuals with peanut allergy reacting to peanut at doubleblind, placebo-controlled food challenge (DBPCFC) and were published between January 2010 and September 2020. We undertook a systematic review of the literature to identify studies that have undertaken double-blind, placebo-controlled FCs (DBPCFCs) in individuals with peanut allergy (adults and children) conducted in a manner consistent with international consensus criteria.[12] Study sponsors and/or authors were contacted and asked to provide both aggregate and (in the case of individuals who underwent repeat peanut challenge) anonymized IPD that could be included for meta-analysis. We searched MEDLINE for articles that were published between January 2010 and September 2020 and described DBPCFC to peanut; we used the search terms double-blind and peanut. We reviewed the reference lists of the included studies and review articles to identify other relevant studies
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