Seed Storage Proteins, 2S Albumin And 11S Globulin, Associated to Severe Allergic Reactions after Flaxseed Intake
Bueno-Díaz C1, Biserni C2, Martín-Pedraza L3, de las Heras M4, Blanco C5, Vázquez-Cortés S6, Fernández-Rivas M6, Batanero E1, Cuesta-Herranz J4, Villalba M1
1Department of Biochemistry and Molecular Biology, Chemistry Faculty, Complutense University of Madrid, Madrid, Spain
2Department of Food, Environmental and Nutritional Sciences DEFENS, University of Milan, Milan, Italy
3Allergy Department, Hospital Universitario Infanta Leonor, Madrid, Spain
4Hospital Universitario Fundación Jiménez Díaz, Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD, UAM), RETIC ARADyAL, Instituto de Salud Carlos III, Madrid, Spain
5Allergy Department, Hospital Universitario La Princesa, Instituto de Investigación Sanitaria Princesa (IP), Madrid, Spain
6Allergy Department, Hospital Clínico San Carlos, IdISSC, ARADyAL, Madrid, Spain
J Investig Allergol Clin Immunol 2022; Vol. 32(5)
Background: Given the increased popularity of flaxseed in meals, several cases of allergy to these seeds have been reported. Little is known about allergens implicated in hypersensitivity reactions to these seeds. The present work aimed to identify the allergens involved in IgE-mediated reactions in five patients with a clinical history of severe systemic symptoms after flaxseed consumption.
Methods: Proteins susceptible to be allergens with IgE-binding capacity were purified from flaxseed extract by chromatographic techniques. Their identification was achieved via MALDI-TOF mass spectrometry. Immunoassays were performed using the five allergic patient’s era either by testing them individually or as a pool.
Results: Four out of five patients recognized a low-molecular-mass protein (around 13kDa) by immunoblotting of the flaxseed extract, while two patients recognized a protein of approximately 55 kDa. They were identified by mass spectrometry as flaxseed 2S albumin, included into WHO/IUIS allergen nomenclature as Lin u 1,and 11S globulin, respectively. Inhibition assays revealed in vitro IgE-cross-reactivity of Lin u 1 with peanut and cashew nut proteins, while IgE recognition of 11S globulin by patients’ sera was partially inhibited by several plant-derived sources.
Conclusions: Seed storage proteins from flaxseed were involved in the development of severe symptoms in five individuals and exhibited cross-reactivity with other allergenic sources. Besides the severity of flaxseed allergy in patients sensitized to 2S albumin, it is the first time that the 11S globulin is identified as a potential allergen. We consider that these data should be taken into account for a more accurate diagnosis of patients.
Key words: Food allergy, Flaxseed, 2S albumin, 11S globulin, Cross-reactivity, Anaphylaxis