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Component testing for pollen-related, plant-derived food allergies

Julie Wang, MD
Section Editor
Scott H Sicherer, MD, FAAAAI
Deputy Editor
Elizabeth TePas, MD, MS


Advances in the identification of clinically relevant allergens and the development of recombinant proteins allow for assessment of immunoglobulin E (IgE) binding to individual proteins within an allergenic food. This type of testing is known as component-resolved diagnosis (CRD). Increased sensitivity and specificity can be achieved by assessing IgE binding to separate proteins, either purified native or recombinant, thereby providing improved diagnostic accuracy for predicting clinical reactivity. CRD may also provide additional prognostic information regarding the severity or persistence of food allergies.

CRD testing for pollen-related, plant-derived food allergies is reviewed here. Component testing for animal-derived food allergies is discussed separately. An overview of testing for food allergies is also presented separately. (See "Component testing for animal-derived food allergies" and "Diagnostic evaluation of food allergy".)


Allergies to plant-derived foods may occur in pollen-sensitized individuals due to pollen allergens that cross-react with food allergens, such as profilins or pathogenesis-related class 10 (PR-10) proteins that are homologues of the major white birch pollen antigen (Betula verrucosa 1 [Bet v 1]). This type of allergy is associated with symptoms that are generally limited to the oropharyngeal area (oral allergy syndrome/pollen-food allergy syndrome). In the absence of sensitization to pollens, allergies to plant-derived foods are the result of sensitization to more stable proteins, such as the seed storage or lipid transfer proteins (LTPs). In these cases, reactions are more often systemic, and there is a higher risk for anaphylaxis [1]. (See "Pathogenesis of oral allergy syndrome (pollen-food allergy syndrome)" and "Clinical manifestations and diagnosis of oral allergy syndrome (pollen-food allergy syndrome)".)

Component-resolved diagnosis (CRD) entails measurement of specific immunoglobulin E (IgE) responses to individual allergens as opposed to measuring IgE responses to allergen extracts that contain a mixture of proteins, including ones that may have greater or less clinical relevance. The pattern of specific IgE reactivity to defined allergens can help determine which patients are at higher risk for allergic reactions versus those who are sensitized but clinically tolerant. It may also help distinguish between those who are at risk for more severe reactions versus those who are likely to have milder symptoms.

The prime example of the utility of CRD in the management of food allergy is peanut allergy [2]. Several studies have noted that having detectable levels of specific IgE to the seed storage proteins are associated with more severe, persistent peanut allergy [3-7], whereas exclusive sensitization to a Bet v 1 homologue is more often associated with a low risk of reactivity to peanut [8,9]. (See "Peanut, tree nut, and seed allergy: Diagnosis" and 'Peanut' below.)

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Literature review current through: Oct 2017. | This topic last updated: Sep 08, 2017.
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