Cor a 11
Summary
Cor a 11 is a 7S globulin vicilin-like seed storage protein from hazelnut (Corylus avellana). It is a cupin-superfamily protein (~48 kDa monomer, trimer ~150 kDa) localized in the nut cotyledon. Cor a 11 represents a major storage-protein allergen associated with severe, systemic hazelnut allergy, particularly in children and in individuals from birch-endemic regions with genuine nut sensitization. It belongs to the family of heat- and digestion-stable storage proteins together with Cor a 9 and Cor a 14.
Epidemiology
Hazelnut is among the most clinically relevant tree nuts in Europe, with geography- and age-dependent patterns of sensitization. In birch-endemic northern Europe, mild oral-allergy syndrome predominates due to cross-reactivity with Bet v 1, whereas in southern Europe and among children, storage-protein sensitization (Cor a 9, Cor a 11, Cor a 14 and Cor a 16) is more common and linked to systemic reactions. In a Belgian cohort, 36 % of preschoolers and 40 % of school-age children with systemic reactions had IgE to Cor a 11. In a Spanish pediatric cohort, Cor a 11-specific IgE correlated strongly with severe reactions during oral food challenge.
Route Of Exposure
Cor a 11 has intermediate heat stability and may remain allergenic in processed foods such as chocolate or baked goods.
Clinical Relevance
Cor a 11 sensitization is a marker of systemic hazelnut allergy, independent of birch pollen sensitization. Hazelnut allergic children with IgE to Cor a 11 typically exhibit generalized or anaphylactic reactions, while adults with pollen-related oral allergy syndrome are rarely sensitized to Cor a 11. In a Spanish pediatric study, Cor a 11 IgE predicted severe outcomes during food challenges. This profile indicates persistent, high-risk hazelnut allergy with reactions even to small or processed quantities.
Diagnostics
Component-resolved diagnosis using recombinant Cor a 11 may improve discrimination between primary hazelnut allergy and birch-pollen cross-reactivity. IgE testing to Cor a 11 can predict true systemic allergy with high specificity, especially in combination with Cor a 9 and Cor a 14 component IgE testing.
Prevention And Therapy
There is currently no regulatory approved hazelnut component oral immunotherapy available. Management relies on avoidance, food labelling vigilance, and when indicated, adrenaline auto-injector prescription. A clinical study of hazelnut oral immunotherapy that included monitoring of immunological responses to storage proteins such as Cor a 11, Cor a 9, Cor a 14 and Cor a 16 has shown the treatment to be safe and effective.
Cross-Reactivity
Cor a 11 shares 60–70 % amino-acid identity with vicilins from walnut (Jug r 2, Jug r 6), pecan (Car i 2), cashew (Ana o 1), and peanut (Ara h 1). Functional inhibition confirms overlapping IgE-binding epitopes which may contribute to clinical cross-reactivity among nuts.
Explained Results
Allergen information
Cor a 11 is a 7S globulin (vicilin). It belongs to the group of heat- and digestion-stable seed storage proteins together with Cor a 9 and Cor a 14.
Clinical relevance
Cor a 11 sensitization is a marker of risk for systemic hazelnut allergy, independent of birch pollen sensitization.
Cross-reactivity
Cor a 11 shares 60–70 % amino-acid identity with vicilins from walnut (Jug r 2, Jug r 6), pecan (Car i 2), cashew (Ana o 1), and peanut (Ara h 1).
References
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