Specific allergen profiles of peanut foods and diagnostic or therapeutic allergenic products

Abstract

Generic immunoassays for peanut cannot discriminate between allergen levels in peanut-derived food products or therapeutics. Clinical trials of oral immunotherapy (OIT) are strengthened by using standardized peanut preparations with defined doses of major allergens. This article describes measurement of Ara h 1, Ara h 2, and Ara h 6 in peanut foods and in peanut flour extracts used for allergy diagnosis and OIT. Monoclonal antibody-based enzyme immunoassays for Ara h 1, Ara h 2, and Ara h 6 were used to compare allergen levels in peanut (n=16) and tree nut (n=16) butter, peanut flour (n=11), oils (n=8), extracts used for diagnosis and OIT (n=5), and the National Institute for Standards and Technology Peanut Butter Standard Reference Material 2387. Roasted peanut butters contained 991 to 21,406μg/g Ara h 1 and exceeded Ara h 2 and Ara h 6 levels by 2- to 4-fold. Similarly, National Institute for Standards and Technology Peanut Butter Standard Reference Material 2387 contained 11,275μg/g Ara h 1, 2,522μg/g Ara h 2, and 2,036μg/g Ara h 6. In contrast, peanut flours contained 787 to 14,631μg/g Ara h 2 and exceeded Ara h 1 levels by 2- to 20-fold. Flour extracts used for OIT contained 394 to 505μg/mL Ara h 1, 1,187 to 5,270μg/mL Ara h 2, and 1,104 to 8,092μg/mL Ara h 6. In most cases specific peanut allergens were not detected in tree nut butters or peanut oils. The results show marked differences in specific peanut allergen profiles in peanut butter and flour and peanut preparations for clinical use. Roasting can increase Ara h 1 levels in peanut butter. Variability in allergen levels could affect the outcome of clinical trials of peanut OIT, especially with respect to Ara h 1. Specific allergen measurements will improve standardization and provide accurate dosing of peanut preparations that are being used for OIT.