New food allergies in a European non-Mediterranean region: is Cannabis sativa to blame?

Background: Allergy to fruit and vegetables exhibit geographic variation regarding the severity of symptoms and depending on the sensitization profile of the patient. These sensitization profiles and routes remain incompletely understood. Cannabis is a very popular drug and derived from Cannabis sativa, a plant containing lipid transfer proteins (LTP) also known as important allergens in plant and fruit allergies. In this study we sought to elucidate a potential connection between C. sativa allergy and plant food allergies. Methods: A case-control study involving 21 patients consulting for plant food allergies. Twelve patients were cannabis allergic and 9 had a pollen or latex allergy without cannabis allergy. Testing for cannabis IgE implied measurement of specific IgE, skin testing and basophil activation tests. Allergen component analysis was performed with a microarray technique. Results: Plant food allergy in patients with documented cannabis allergy had more severe reactions than patients without cannabis allergy and frequently implied fruits and vegetables that are not observed in a (birch) pollen-related food syndrome. With the exception of 1 patient with cannabis allergy, all were sensitized to nonspecific (ns)-LTP. Conclusion: Our data suggest that illicit cannabis abuse can result in cannabis allergy with sensitization to ns-LTP. This sensitization might result in various plant-food allergies. Additional collaborative studies in different geographical areas are needed to further elucidate on this hypothesis.