Concomitant sensitization to legumin, Fag e 2 and Fag e 5 predicts buckwheat allergy

Abstract

SummaryBackgroundBuckwheat (Fagopyrum esculentum) has become increasingly popular as a healthy food in Europe. However, for sensitized individuals, consumption can cause anaphylactic reactions. The aim of this study was to identify individual well‐characterized buckwheat allergens for component‐resolved diagnosis.MethodsPatients were selected by positive skin prick test to buckwheat and divided into two groups: (1) sensitized to buckwheat without clinical symptoms and (2) buckwheat allergy. Buckwheat proteins were extracted from raw buckwheat seeds, purified applying a combination of protein precipitation and chromatographic methods, and analyzed by IgE immunoblotting and ELISA.ResultsBuckwheat‐allergic patients had a significantly larger median skin prick test weal diameter for buckwheat than the sensitized group and the positive control. Also, IgE immunoblotting clearly showed a distinct pattern in sera from allergic patients when compared to sensitized individuals. Several IgE‐reactive proteins were purified from crude buckwheat extract, namely legumin (Fag e 1 plus its large subunit), Fag e 2 (2S albumin), and newly identified Fag e 5 (vicilin‐like) as well as hevein‐like antimicrobial peptides, designated Fag e 4. All four allergens showed superior diagnostic precision compared to extract‐based ImmunoCAP with high sensitivity as well as high specificity.ConclusionsPatients with clinical symptoms clearly show a distinct allergen recognition pattern. We characterized a buckwheat vicilin‐like protein as a new relevant marker allergen, designated Fag e 5. Additionally, another new allergen, Fag e 4, potentially important for cross‐reactivity to latex was added to the allergen panel of buckwheat. Further, our data show that the full‐length legumin comprising both, large and small subunit should be applied for component‐resolved diagnosis. Our data indicate that concomitant sensitization to legumin, Fag e 2 and Fag e 5, predicts buckwheat allergy.

A WAO — ARIA — GA2LEN consensus document on molecular-based allergy diagnosis (PAMD@): Update 2020

“…Buckwheat allergy is predicted by concomitant sensitization to legumin, Fag e 2, and Fag e 5. 209 IgE to Fag e 3 correlates with a risk for anaphylaxis. 210 Interestingly, horses may also develop IgE to buckwheat from their diet.…”

Occupational buckwheat allergy as a cause of allergic rhinitis, asthma, contact urticaria and anaphylaxis—An emerging problem in food‐handling occupations?

“…[39][40][41][42][43][44][45][46] Concomitant sensitization to Fag e 1, Fag e 2, and Fag e 5, has been suggested to predict symptomatic buckwheat allergy. 47 On the other hand, Fag e 3-IgE has been reported to predict oral food challenge results and anaphylaxis. 48 Cross-reactivity between buckwheat and several other allergens, including natural rubber latex, poppy seed, and coconut has been described.…”

“…Previously, the usefulness of buckwheat IgE has been critically evaluated, 53 44,47 These would be useful in diagnosing buckwheat allergy in cases where skin prick testing is not feasible or must be refrained from performing. We suggest that the safety of The possibility of buckwheat allergy should be kept in mind when examining workers from food-handling occupations with symptoms suggestive of immediate (Type I) allergy.…”

Understanding buckwheat allergies for the management of allergic reactions in humans and animals

“…Recently, Fag e 4 and Fag e 5 have been identified as buckwheat allergens as they reacted with the sera from patients with buckwheat allergy (Geiselhart et al 2018). Fag e 4 is a hevein-like antimicrobial peptide, which comprises 40 amino acid residues and is potentially crossreactive with latex.…”