Stephanie Filep1, Denise S Block1, Bryan R E Smith1, Eva M King1, Scott Commins2, Michael Kulis3, Brian P Vickery3, Martin D Chapman4. 1. INDOOR Biotechnologies, Charlottesville, Va. 2. Division of Pediatric Allergy, University of Virginia Health Sciences Center, Charlottesville, Va. 3. Department of Pediatric Allergy, University of North Carolina School of Medicine, Chapel Hill, NC. 4. INDOOR Biotechnologies, Charlottesville, Va. Electronic address: mdc@inbio.com.
Abstract
BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: Roasted peanut butters contained 991 to 21,406 μg/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 11,275 μg/g Ara h 1, 2,522 μg/g Ara h 2, and 2,036 μg/g Ara h 6. In contrast, peanut flours contained 787 to 14,631 μg/g Ara h 2 and exceeded Ara h 1 levels by 2- to 20-fold. Flour extracts used for OIT contained 394 to 505 μg/mL Ara h 1, 1,187 to 5,270 μg/mL Ara h 2, and 1,104 to 8,092 μg/mL Ara h 6. In most cases specific peanut allergens were not detected in tree nut butters or peanut oils. CONCLUSIONS: 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.
BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: Roasted peanut butters contained 991 to 21,406 μg/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 11,275 μg/g Ara h 1, 2,522 μg/g Ara h 2, and 2,036 μg/g Ara h 6. In contrast, peanut flours contained 787 to 14,631 μg/g Ara h 2 and exceeded Ara h 1 levels by 2- to 20-fold. Flour extracts used for OIT contained 394 to 505 μg/mL Ara h 1, 1,187 to 5,270 μg/mL Ara h 2, and 1,104 to 8,092 μg/mL Ara h 6. In most cases specific peanut allergens were not detected in tree nut butters or peanut oils. CONCLUSIONS: 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.