Cannabis allergy and associated food allergies: Exploring their true colors
15 March 2019
UAntwerp - Campus Drie Eiken - Building O - Auditorium O3 - Universiteitsplein 1 - 2610 WILRIJK (route: UAntwerpen, Campus Drie Eiken
Prof D. Ebo, Prof M. Haagendorens & M. Faber, MD
PhD defence Ine Decuyper - Faculty of Medicine and Health Sciences
Abstract (Presentation in English)
This thesis describes the largest cannabis allergic population up to now (n=120) confirming that cannabis allergy can manifest itself with a wide variety of clinical symptoms ranging from mild to severe anaphylaxis. Symptoms can be induced by cannabis smoking, cutaneous contact and/or ingestion. Moreover, a considerable number of patients report symptoms on mere passive smoke exposure and nearly half report systemic reactions to plant-derived foods.
This dissertation revealed that Can s 3 (the nsLTP of Cannabis sativa) is a major cannabis allergen in our regions. Although the significance of OEEP2 and RuBisCO proteins as candidate cannabis allergens was also explored preliminary, they could not be identified as important allergens in our region.
Secondly, new cannabis diagnostics were developed and validated as up to now, diagnosis was mainly based on unstandardized prick prick tests. It was evidenced that the in-lab developed Can s 3 based diagnostics (BAT rCan s 3, specific (s)IgE rCan s 3 and the skinprick test with an nCan s 3 rich extract) are equally reliable and have the best performance compared to sIgE hemp and BAT with a crude cannabis extract. Because Can s 3 based diagnostics are commercially unavailable, we advise the sIgE hemp assay where there’s an unequivocal history of cannabis-related symptoms, as a negative result indicates a negligible risk of cannabis allergy. Nevertheless, a positive result needs further diagnostic exploration.
Concerning the risk of cannabis allergy following occupational cannabis exposure, our pilot study was not able to identify any causative allergenic factors for the reported symptoms on cannabis exposure in this population. However, as the reported symptoms are plentiful, extensive protective clothing was recommended during occupational cannabis exposure.
Finally, to be able to diagnose Can s 3 related plant-food allergies more efficiently, a diagnostic exploration of Pru p 3 and/or Mal d 3 sensitized patients (nsLTPs from peach and apple respectively and responsible for some of the cannabis related plant-food reactions) was performed. Patients from Antwerp and Barcelona were compared showing that there are important geographical differences both in allergy profile and in the ability of diagnostics to discriminate clinically relevant from irrelevant nsLTP-sensitizations.
In conclusion, this dissertation ascertains that cannabis allergy merits a place as a genuine allergy entity causing a variety of symptoms and cross-reactive plant-derived food allergies. We have identified reliable standardized diagnostics for cannabis allergy with Can s 3 playing an important role as cannabis allergen in our region.