D1.29 - Class III Chitinases as Potential Allergens in Raspberry-Induced Anaphylaxis

Raspberry allergy is rare but can manifest as severe anaphylaxis. Class III chitinases, associated with plant defense, have emerged as potential allergens in various fruits. This study investigates the allergenic profile of raspberry in a pediatric patient with anaphylaxis.

An 11-year-old girl presented anaphylaxis 60–90 minutes after raspberry ingestion, including urticaria, abdominal pain, vomiting, ear angioedema, and respiratory symptoms. Skin prick tests indicated sensitization to raspberry. Also, IgE-specific assays confirmed sensitization to strawberry and lipid transfer proteins (LTPs). The patient tolerates strawberry and other fruits and vegetables.

Protein extracts from raspberry, peach and strawberry were analyzed using SDS-PAGE and Western blot under reducing and non-reducing conditions to assess IgE binding, with protein concentrations measured using the Bradford method.

Western blot revealed IgE binding to 30 kDa bands in raspberry extracts under both reducing and non-reducing conditions, consistent with class III chitinases. Additional reactivity was observed at 12 kDa under non-reducing conditions. In peach, bands at 14 kDa (non-reducing) and 11 kDa (reducing) corresponded to Pru p 3 (LTP). Strawberry showed weaker IgE binding with no specific bands identified.

Class III chitinases appear to play a key role in raspberry-induced anaphylaxis. Molecular characterization of these allergens will support more accurate diagnosis and personalized treatment strategies in fruit allergies.