The Usefulness of Component-Resolved Diagnostics in Food Allergy

© Copyright The Korean Academy of Asthma, Allergy and Clinical Immunology • The Korean Academy of Pediatric Allergy and Respiratory Disease http://e-aair.org The gold standard for the diagnosis of IgE-mediated food allergy is an oral food challenge (OFC) that directly verifies the causal relationship between clinical symptoms and offending foods. However, OFC carries a risk of developing fatal reactions (such as anaphylaxis) in some patients. A thorough history taking and supportive tests such as a skin prick test (SPT) or serum food-specific IgE (sIgE) levels have been used in clinical practices for the diagnosis of IgE-mediated food allergy. A SPT or serum test can be performed easily and safely in an outpatient clinic setting. However, clinicians must be cautious in interpretation due to the possibility of a false positive or false negative test results. SPT or serum tests also have limitations and cannot replace OFC for the diagnosis of food allergy. Component-resolved diagnostics (CRD) is a diagnostic test to detect specific IgE against individual allergen molecules or components using purified native or recombinant allergens. It is expected that CRD could provide further diagnostic information in patients with an IgE-mediated food allergy in terms of predicting clinical relevance or prognosis. The level of specific IgE toward Ara h 2 was correlated with a clinical threshold in patients with a peanut allergy. In a study that compared patients with a peanut allergy from 3 countries (Spain, the United States, and Sweden), American patients frequently had IgE against Ara h 1 to 3 that often manifested with severe symptoms, while sensitization to Ara h 9 and Ara h 8 were primarily found in Spanish and Swedish patients, respectively. One study that included 37 adults presented the accuracy of a specific IgE antibody toward rPen a 1 for shrimp allergy. Yang et al reported that sIgE antibodies to shrimp tropomyosin is more useful than a skin prick test to predict clinically relevant reactions in patients with shrimp allergy. An Italian study of egg allergy showed that 94% of Gal d 1 negative patients tolerated boiled egg; however, 95% of Gal d 1 positive patients reacted to raw egg. This study suggests that sIgE against Gal d 1 appears to be a good predictor of egg allergy. There have been more studies to report the higher diagnostic value of food allergies The Usefulness of Component-Resolved Diagnostics in Food Allergy Kangmo Ahn*