D1.287 - Polysensitization to Seed Storage Proteins, LTPs and Profilin in a Patient With Anaphylaxis After Consumption of Pesto Sauce

Nut allergy is a frequent trigger of systemic reactions, typically mediated by seed storage proteins (2S, 7S, 11S), lipid transfer proteins (LTPs) and, less commonly, profilins. In individuals with broad pollen allergy and multiple food sensitizations, clinical interpretation becomes challenging, as cross-reactive panallergens may coexist with genuine primary nut sensitization. Molecular diagnostics such as ALEX³, SDS-PAGE and IgE–Western blot are essential to identify the specific allergenic proteins involved and to determine their clinical relevance.

A 45-year-old woman with perennial rhinitis, pollen-induced asthma and a history of oral allergy to several fruits developed anaphylaxis shortly after consuming pizza with green sauce (suspected pesto). Her history included prior reactions to almond and hazelnut and strong skin test reactivity to multiple nuts. Diagnostic work-up included extensive skin prick testing to inhalants, foods and nuts; prick-by-prick testing with suspected ingredients; and measurement of total IgE (1438 IU/mL), tryptase and specific IgE to nuts, LTPs, profilin and storage-protein components. Protein extracts from cashew, hazelnut, walnut, pine nut and pistachio were prepared by PBS extraction and lyophilization, and molecular characterization was performed by SDS-PAGE and IgE–Western blot using the patient’s serum.

Skin prick testing demonstrated strong sensitization to hazelnut, walnut, almond, pine nut, pistachio and cashew, together with intense reactivity to profilin. Specific IgE showed markedly elevated levels to walnut (161 kU/L) with Jug r 1 as the dominant component, and to hazelnut (11.4 kU/L) with Cor a 9, alongside additional positivity to several LTP-containing nuts (Cor a 8, Ara h 9, Pru p 3). IgE–Western blot revealed in walnut a prominent 10–15 kDa band compatible with Jug r 1/Jug r 3 and weaker 37–50 kDa bands suggestive of Jug r 2/Jug r 6. Secondly, in hazelnut and pine nut, a fainter band pattern can be observed that could be associated with different storage proteins, such as Cor a 9 (37–50 kDa) and Cor a 8/Pin p 1 (10–15 kDa). Overall, the molecular profile confirmed broad recognition of 2S, 7S and 11S storage proteins together with LTPs and profilin.

The clinical, serological and molecular findings demonstrate polysensitization to storage proteins (Jug r 1, Cor a 9, Pin p 1), LTPs (Cor a 8, Pru p 3) and profilin, consistent with the patient’s history of nut-induced anaphylaxis. The reaction related to pesto is best explained by primary sensitization to walnut and hazelnut storage proteins, with the possible additional cross-reactivity to other nuts. SDS-PAGE and IgE–Western blot were crucial for defining the molecular basis of the reaction and for clarifying the patient’s risk profile across different nuts.