Cor a 16
Allergen
Summary
Cor a 16 was identified in 2022 as a vicilin-like 7S globulin from Corylus avellana. It belongs to the same protein family as Cor a 11 but features an extended N-terminal region which undergoes proteolytic processing, yielding multiple IgE-binding fragments. Cor a 16 extends the family of hazelnut vicilins and may explain complex IgE responses in hazelnut-sensitized patients.
Epidemiology
Cor a 16 appears as a major allergen to which approximately 80% of hazelnut-sensitized paediatric sera (n=106) from the US were sensitized, with IgE levels ranging up to over 100 kUA/L. Twenty of the 106 samples (19%) tested positive for one of the two vicilins Cor a 11 and Cor a 16, but negative for the other. Of these 20 samples, 18 were uniquely positive to Cor a 16 and 2 to Cor a 11.
Route Of Exposure
It is likely that Cor a 16 and its fragments persist after roasting, baking, and digestion, remaining allergenic in trace amounts within processed or composite foods.
Clinical Relevance
Cor a 16 fragments maintain IgE activity and may explain complex IgE responses in hazelnut-sensitized patients.
Diagnostics
Recombinant Cor a 16 is available for in vitro IgE testing, enhancing identification of primary hazelnut allergy. Combined measurement of IgE to Cor a 9, 11, 14, and 16 may improve sensitivity and accuracy of risk assessment.
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, involving patients predominantly sensitized to Cor a 9, Cor a 14, and Cor a 16, demonstrated effective desensitization and a concomitant decrease in IgE to Cor a 16.
Cross-Reactivity
Cor a 16 belongs to the same protein family as Cor a 11 but features an extended N-terminal region that undergoes proteolytic processing during protein maturation, yielding multiple IgE-binding fragments. Cor a 16 share similarities with segments in the N-terminal region of vicilin-like proteins from macadamia, walnut and pecan, however there are limited cross-reactivity data available for Cor a 16.
Explained Results
Allergen information
Cor a 16 is a recently identified 7S globulin (vicilin) featuring an N-terminal region subject to proteolytic processing, yielding multiple IgE-binding fragments.
Clinical relevance
Cor a 16 extends the family of hazelnut vicilins and may explain complex IgE responses in hazelnut-sensitized patients.
Cross-reactivity
Cor a 16 is related in structure to Cor a 11 and shares similarities with segments in the N-terminal region of vicilin-like proteins from macadamia, walnut and pecan. However, there are limited cross-reactivity data available for Cor a 16.
References
- Amoroso CG, Andolfo G. Hazelnut allergome overview and Cor a gRNAs identification. BMC Plant Biol. 2025;25:661.
- Barre A, Sordet C, Culerrier R, Rancé F, Didier A, Rougé P. Vicilin allergens of peanut and tree nuts (walnut, hazelnut and cashew nut) share structurally related IgE-binding epitopes. Mol Immunol. 2008;45:1231-40.
- Elizur A, Koren Y, Appel MY, Nachshon L, Levy MB, Epstein-Rigbi N, Mattsson L, Holmqvist M, Lidholm J, Goldberg MR. Hazelnut Oral Immunotherapy Desensitizes Hazelnut But Not Other Tree Nut Allergies (Nut CRACKER Study). J Allergy Clin Immunol Pract. 2025;13:833-841.
- Holzhauser T, Stephan O, Vieths S. Detection of potentially allergenic hazelnut (Corylus avellana) residues in food: a comparative study with DNA PCR-ELISA and protein sandwich-ELISA. J Agric Food Chem. 2002;50:5808-15.
- Mattsson L, Holmqvist M, Porsch H, Larsson H, Pontoppidan B, Valcour A, Lidholm J. A new vicilin-like allergen in hazelnut giving rise to a spectrum of IgE-binding low-molecular-weight N-terminal fragments. Clin Exp Allergy. 2022;52:1208-1212.