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Allergen Profile, Brazil Nut, IgE With Component Reflexes
The Brazil nut component profile includes allergen-specific IgE to whole Brazil nut extract. This test reflexes Brazil nut component Ber e 1 when the Brazil nut extract result is >0.10 kU/L.
The measurement of specific immunoglobulin E (IgE) to individual components of an allergen, either purified native or recombinant, is referred to as component resolved diagnosis (CRD).1-5 This approach represents an improvement over traditional measurement of IgE to allergen extracts that contain a mixture of proteins. The pattern of specific IgE reactivity to component allergens can predict which patients are at higher risk for systemic allergic reactions versus those who are sensitized but clinically tolerant. CRD can also be used to predict which patients are at risk for more severe reactions and which patients are likely to have milder symptoms.
Allergies to plant-derived foods can occur as the result of sensitization to relatively stable proteins, such as the seed storage or lipid transfer proteins. Sensitization to this type of protein can be associated with more severe, systemic reactions and a higher risk for anaphylaxis. Alternatively, allergies to plant-derived foods may occur in pollen-sensitized individuals due to pollen allergens that cross-react with food allergens. Examples of pollen-associated allergens are the profilins or PR10 proteins that are homologues of the major white birch pollen antigen Bet v 1. Allergy to this family of proteins is associated with symptoms that are generally limited to the oropharyngeal area (commonly referred to as the oral allergy syndrome of pollen food allergy syndrome).
Component resolved diagnostics can help to1-5:
• Distinguish between allergy due to cross-reactivity and primary allergy.
• Improve risk assessment using allergen components.
• Improve management of allergic patients.
Thermo Fisher ImmunoCAP® allergen-specific IgE
Allergy to Brazil nut is relatively common in the United States.6
Brazil Nut Component
• Ber e 1 is a storage protein that is highly abundant in Brazil nut and serves as an energy source for the seed during growth of a new plant.7,8
• Sensitization to 2S albumins, such as Ber e 1, is known to be associated with systemic food reactions.7-13
• Ber e 1 is heat- and digestion-stable14,15
• Associated with systemic reactions16,17
• Positive Brazil nut extract IgE results with negative Ber e 1-specific IgE results may be explained by sensitization to:
− Other Brazil nut storage proteins or lipid transfer protein (LTP)
− Pollen proteins like profilin or PR10 proteins
− CDC (cross-reacting carbohydrate determinants)
0.5 mL (Note: this volume does not allow for repeat testing.)