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R-mandelonitrile-lyase, homolog to Pru d 10, is a major peach allergen in peach allergic Spanish population

López-Matas MA1*, Vílchez-Sánchez F2*, Álvarez F1, Rodriguez-Perez R2, Dominguez-Ortega J2, Carnes J1, Pedrosa M2,3

1R&D Unit, LETI Pharma S.L.U., Tres Cantos, Madrid, Spain
2Department of Allergy, Hospital Universitario La Paz, Institute for Health Research (IdiPAZ), Madrid, Spain
3Center for Biomedical Research Network on Rare Diseases (C IBERER U754), Madrid, Spain
*Both authors contributed equally

J Investig Allergol Clin Immunol 2025; Vol. 35(2)
doi: 10.18176/jiaci.0972

Background: Peach allergy is a prevalent cause of food allergy. Despite the repertoire of allergens available for molecular diagnosis, there are still patients with undetectable IgE levels to peach allergens but presenting symptoms after its ingestion. The objective of this study was to investigate the allergenic profile in a patient population with symptoms produced by peach.
Materials and Methods: An exploratory retrospective study was performed with patients presenting symptoms after the ingestion of peach. Forty-two patients were included in the study. The allergenic profile of individual patients was investigated by immunoblot. A serum pool was prepared with the sera that recognized a 70 kDa band. This pool was used to detect this protein in peach peel and pulp and to identify the 70 kDa protein in 2D immunoblot. Spots recognized in the 2D immunoblot were sequenced by LC-MS/MS. Inhibition studies were performed between peach peel and almond.
Results: Twenty-two patients (52.4%) recognized the 70 kDa protein in immunoblot. This protein was recognized in peel and pulp. Two different spots were observed in 2D-PAGE, both were identified as (R)-mandelonitrile lyases (RML) with high amino acid similarity with Pru du 10. Peach RML were partially inhibited with an almond extract. No association was found between any reported symptom and sensitization to RML. RML-sensitized patients were older and reported pollen associated respiratory symptoms more frequently than negative patients.
Conclusions: A new peach allergen, a RML, homologous of Pru du 10, recognized by 52% of the population has been identified.

Key words: Peach allergy, Peach allergen, Mandelonitrile lyase, Food allergy, Pru du 10 homologous