D1.286 - Allergenic Protein Profiling in a Patient with Long-standing Nut-Induced Anaphylaxis

Nut allergy is a frequent cause of food-induced anaphylaxis in adults. This case describes a patient with a 20-year history of recurrent anaphylactic episodes triggered by different nuts and seeds, with variable latency and clinical severity. Despite strict dietary avoidance, the patient continued to experience reactions. The objective of this study was to determine the patient’s sensitization profile using protein extraction, SDS-PAGE, and IgE-Western blot to identify the allergenic components potentially responsible for the reactions.

Protein extracts were prepared from hazelnut, peanut, pistachio, cashew, pine nut, walnut, sunflower seed, and sesame following standardized extraction. SDS-PAGE was used to characterize the protein profile of each extract, and IgE-Western blot was conducted using patient serum to determine specific IgE recognition patterns. Analytical data were compared with the patient’s clinical history and specific IgE results obtained during follow-up.

SDS-PAGE revealed distinct protein profiles across sources. IgE-Western blot analysis showed IgE recognition in all extracts except peanut, consistent with the negative specific IgE levels. Relevant bands were observed in the 37–50 kDa region for hazelnut, potentially corresponding to storage proteins Cor a 11 and Cor a 9. Pistachio showed a weak band near 25 kDa, suggestive of Pis v 4. Walnut recognition included bands between 50–75 kDa, possibly Jug r 4 and Jug r 2, and a ∼20 kDa band compatible with Jug r 5. Sesame displayed two bands between 10–15 kDa, likely Ses i 1 and Ses i 2. Cashew exhibited intense bands in the 10–20 kDa range, compatible with Ana o 3. Some higher-molecular-weight bands in pine nut and sunflower seed were not identifiable as major known allergens.

The patient shows sensitization to multiple nuts and seeds, predominantly to 2S, 7S, and 11S storage proteins, which may explain the persistence and heterogeneity of symptoms despite avoidance. Unidentified bands may represent protein fragments under reducing conditions and could contribute to the patient’s allergic responses. This comprehensive allergenic profiling supports the clinical diagnosis and may guide patient-specific management strategies.