Allergy to Anacardiaceae: description of cashew and pistachio nut allergens.

Some members of the Anacardiaceae family, such as cashew nut, pistachio nut and mango, have been reported to cause immediate allergic reactions. We report three cases of anaphylaxis to cashew nuts. With the aim of describing the allergens existing in cashew and pistachio nuts, patients were prick tested with cashew and pistachio extracts. Specific IgE against both nuts was studied by CAP and SDS-PAGE/immunoblotting. It was found that skin tests and specific IgE to cashew and pistachio nuts were positive in the three patients. Both nuts showed several protein bands in SDS-PAGE. The strongest IgE-binding bands had similar molecular weights (15, 30 and 60 kDa) in cashew and pistachio nuts. These main bands were found to be sensitive to reducing agents. It was concluded that these three patients suffered immediate reactions to cashew nut due to an IgE-mediated mechanism.