000103 - Characterization of Allergenic Proteins in Pine Nut: A Clinical Case Study
Background
Allergic reactions to pine nuts (Pinus spp.) are increasingly recognized but remain undercharacterized at the molecular level.
This study presents a clinical case of anaphylaxis following pine nut ingestion and aims to identify the allergenic proteins responsible for the reaction, providing new insights into pine nut sensitization.
Method
A 15-year-old female presented to the emergency room with abdominal pain, vomiting, and pharyngeal discomfort accompanied by facial erythema, five minutes after consuming lasagna containing pine nuts and traces of other nuts.
No skin lesions or cofactors were reported. She was treated with corticosteroids and antihistamines, resulting in symptom improvement.
Subsequent avoidance of nuts was advised. Skin prick tests revealed sensitization to lipid transfer proteins (LTP) and a strong reaction to pine nut extract (22 x 10 mm). Specific IgE (CAP) testing was positive for pine nut (15 kUA/L) but negative for other nuts and LTP-associated allergens.
Protein extracts were prepared from pine nut using PBS extraction, centrifugation, filtration, dialysis, and lyophilization. Protein profiles were analyzed using SDS-PAGE under reducing and non-reducing conditions.
IgE-binding proteins were identified via Western blot using patient serum, and specific IgE levels were quantified through immunoassays. Comparative analyses included recombinant Pru p 3 as a control.
Results
Western blot analysis revealed strong IgE reactivity to a ~15 kDa band in pine nut under non-reducing conditions, consistent with the allergen Pin p 1 (2S-albumin).
Additional bands at ~34 and ~40 kDa were observed, likely corresponding to storage proteins such as vicilin or 11S-globulin.
No reactivity to Pru p 3 was detected in pine nut, despite SDS-PAGE indicating its presence.
Conclusion
The findings confirm Pin p 1 as the primary allergen in the patient’s pine nut allergy.
Other storage proteins may contribute to the sensitization.
This study emphasizes the importance of molecular characterization for accurate diagnosis and management of pine nut allergies.
