Submitted to: Molecular Nutrition and Food Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2012
Publication Date: 11/12/2012
Citation: Cabanillas, B., Cheng, H., Grimm, C.C., Hurlburt, B.K., Rodriguez, J., Crespo, J.F., Maleki, S.J. 2012. Pine nut allergy: clinical features and major allergens characterization. Molecular Nutrition and Food Research. 56:1884-1893. Interpretive Summary: Allergy to tree nuts is one of the leading causes of fatal allergic reactions, and its prevalence appears to be increasing. Pine nuts, the seeds of pine trees, are widely used for human consumption in Europe, America, and Asia. Pine nuts produced in Europe mostly come from Pinus pinea; and they are increasingly used in the preparation of pastries, deserts, pasta, salads and sauces, such as, pesto. The first description of a hypersensitivity reaction to pine nuts was reported by Fine in 1987. Since then, individual case reports of severe anaphylactic reactions to this tree nut have been described. No studies have evaluated IgE-mediated hypersensitivity to pine nut in a large number of patients with details of clinical reactions, nor have pine nut allergens been fully characterized. The aims of this study were to identify, purify, and characterize two specific pine nut proteins recognized by sera from patients with pine nut allergy, and to provide a detailed clinical characterization of reactions to pine nut in a case series of 10 patients diagnosed with actual allergy to this food.
Technical Abstract: Pine nuts, the seeds of pine trees, are widely used for human consumption in Europe, America, and Asia. The aims of this study were to evaluate IgE-mediated hypersensitivity to pine nut in a large number of patients with details of clinical reactions, and to characterize major pine nut allergens. The study included 10 consecutive teenagers and adults diagnosed with IgE-mediated clinical allergy to pine nut. Two major pine nut allergens recognized by sera from patients with pine nut allergy were purified and identified, and the secondary structures and susceptibility to digestion were characterized. Severe reactions represent 80% of allergic reactions to pine nut in this study. Moreover, 70% of the patients were monosensitized to this nut. Two major allergens with molecular weights of 6 and 50 kDa were purified and identified by means of LC/MS/MS as albumin and vicilin, respectively. The 6 kDa protein (albumin), rich in a-helix content, was far more stable to peptic and tryptic digestion as compared with 50 kDa protein (vicilin), which was quickly broken down further. The secondary structure of the purified 50 kDa protein showed 41% ß-sheet, 5% a-helix, and 54% random coil and/or loops. Reactions to pine nuts are severe and the patients are usually monosensitized to this nut. Two major allergens with molecular weights of 6 and 50 kDa were purified and identified as albumin and vicilin, respectively. 6 kDa protein (albumin) showed great stability to peptic and tryptic digestion.