Shanna Bastiaan-Net, Manou R Batstra, Nasrin Aazamy, Huub FJ Savelkoul, Johanna PM van der Valk, Roy Gerth van Wijk, Marco WJ Schreurs, Harry J Wichers and Nicolette W de Jong
Background: Tree nut allergic individuals are often sensitised towards multiple nuts and seeds. The underlying cause behind a multi-sensitisation for cashew nut, hazelnut, peanut and birch pollen is not always clear. We investigated whether IgE cross-reactivity between cashew nut-, hazelnut- and peanut proteins exists in children that are multi-allergic to these foods using a novel IMMULITE®-based inhibition methodology, and investigated which allergens might be responsible. In addition, we explored if an allergy to birch pollen might play a role in this cosensitisation for cashew nut, hazelnut and peanut.
Methods: Serum of five children with a confirmed cashew nut allergy and suffering from allergic symptoms after eating peanut and hazelnut were subjected to inhibition immunoassays using the IMMULITE® 2000 Xpi. Serum specific IgE to seed storage allergens and pathogenesis related protein 10 (PR10) allergens were determined and used for molecular multicomponent allergen correlation analyses with observed clinical symptoms and obtained inhibition data.
Results: IgE cross-reactivity was observed in all patients. Hazelnut extract was a strong inhibitor of cashew nut sIgE (46.8%) while cashew nut extract was less able to inhibit hazelnut extract (22.8%). Peanut extract showed the least inhibition potency. Moreover, there are strong indications that a birch pollen sensitisation to Bet v 1 might play a role in the observed symptoms provoked upon ingestion of cashew nut and hazelnut.
Conclusion: By applying an adjusted working protocol, the IMMULITE® technology can be used to perform inhibition assays to determine the risk of sIgE cross-reactivity between very different food components.