D3.63 - Molecular Evidence of PR-10 in Cannabis Allergy

Cannabis sativa allergy is increasingly recognized, but its molecular allergenic profile was poorly defined. Although nsLTP (Can s 3) is considered the major allergen, emerging evidence suggests additional unidentified allergens. We describe a patient with eyelid dermatitis after consuming cannabis.

A 27-year-old man with severe atopic dermatitis treated with Lebrikizumab developed persistent unilateral eyelid eczema and ocular symptoms. He reported intermittent cannabis use and occupational exposure as a barber. Skin prick testing and patch testing with Cannabis sativa were positive. Serum total IgE was markedly elevated, and molecular diagnostics (ISAC) showed strong sensitization to Fel d 1, Can f 4/5, Bet v 1, nsLTPs and PR-10 proteins.Protein extracts were prepared from marijuana, CBD flowers and hemp seeds using validated extraction protocols. SDS-PAGE and IgE–Western blot were performed under reducing conditions. An additional Western blot using birch pollen extract assessed PR-10 cross-reactivity

SDS-PAGE revealed distinct proteomic profiles for the three cannabis samples, with hemp seeds showing a prominent <10 kDa band. IgE–Western blot showed two consistent IgE-reactive bands at ~9 and ~11 kDa in Marijuana and CBD extracts. But in all extract, we can see a strong ~18 band, most intense in CBD. These band could correspond to Can s 5, a PR-10 protein.Cross-reactivity was confirmed by Western blot using Betula verrucosa extract, where the patient’s serum strongly recognized Bet v 1. Additional shared IgE-reactive bands were detected at ~26 kDa and ~36 kDa, likely representing further cannabis allergens not yet fully characterized. 

The present case showed a complex sensitization profile to Cannabis sativa, dominated by PR-10 but also involving additional allergens. The identification of 9–11 kDa and 26–36 kDa bands suggests that clinically relevant cannabis allergens extend beyond the traditionally described nsLTP.