Potential, pitfalls, and prospects of food allergy diagnostics with recombinant allergens or synthetic sequential epitopes

Abstract

This article aims to critically review developments in food allergy diagnostics with regard to the verification of specific IgE antibodies and the identification of the responsible allergens. Results of IgE-binding tests with food extracts are hampered by cross-reactive proteins, low-quality test agents, or both. Specificity can be increased by defining adequate cutoff values, whereas sensitivity can be improved by using high-quality test agents. IgE-binding tests with purified allergens enabled reliable quantification of allergen-specific IgE titers, with higher levels found in individuals with food allergy compared with individuals without food allergy. However, the overlap in individual test reactivity between allergic and nonallergic subjects complicates interpretation. Recombinant allergens and synthetic sequential epitopes enabled detection of sensitization profiles, with IgE specific to several allergens and substructures now being suggested as markers of severity, persistence, or both. However, high-power quantitative studies with larger numbers of patients are required to confirm these markers. This article aims to critically review developments in food allergy diagnostics with regard to the verification of specific IgE antibodies and the identification of the responsible allergens. Results of IgE-binding tests with food extracts are hampered by cross-reactive proteins, low-quality test agents, or both. Specificity can be increased by defining adequate cutoff values, whereas sensitivity can be improved by using high-quality test agents. IgE-binding tests with purified allergens enabled reliable quantification of allergen-specific IgE titers, with higher levels found in individuals with food allergy compared with individuals without food allergy. However, the overlap in individual test reactivity between allergic and nonallergic subjects complicates interpretation. Recombinant allergens and synthetic sequential epitopes enabled detection of sensitization profiles, with IgE specific to several allergens and substructures now being suggested as markers of severity, persistence, or both.However, high-power quantitative studies with larger numbers of patients are required to confirm these markers. IgE-mediated and non-IgE-mediated syndromes, where IgE-mediated manifestations are responsible for the majority of food-induced, immediate-type, immune-mediated hypersensitivity reactions. 3 The development of an IgE-mediated response to food requires a series of molecular and cellular interactions, which involve antigenpresenting cells, T lymphocytes, and B lymphocytes. [4] and [5] Depending on the route of sensitization, food allergy is the result of either genuine reactivity to comestibles through the gastrointestinal tract (class I food allergens) or secondary sensitization to cross-reactive food allergens as a consequence of the initial reactivity to homologous pollen-related allergens (class II food allergens). [6] and [7] The majority of class I food allergens are heat stable and resistan...

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