Clinical characteristics and IgE-binding protein profiles of patients with buckwheat allergy in China

Background To characterize patients with buckwheat allergy in China and to investigate the associations between clinical manifestations and different buckwheat IgE-binding proteins. Methods Patients diagnosed with buckwheat allergy at the Department of Allergy, Peking Union Medical College Hospital, were followed up between 2023 and 2024 and retrospectively enrolled. Serum allergen-specific IgE (sIgE) levels were measured using the ImmunoCAP system, and buckwheat IgE-binding proteins were identified by immunoblotting. Results A total of 46 patients with buckwheat allergy were included, with a mean age of 26 ± 11 years. 45 patients (97.8%) developed immediate allergic reactions after buckwheat ingestion. Anaphylaxis occurred in 33 patients (73.3%). Seventeen patients (37.0%) experienced respiratory allergic symptoms upon exposure to buckwheat husks. The median f11-sIgE level was 10.75 kUA/L (IQR, 3.01–20.38). Fifteen IgE-binding proteins with different molecular weights were identified, among which the 18–19 kDa protein showed the highest positivity rate (100%). The 14 kDa protein was detected more frequently in patients without anaphylaxis than in those with anaphylaxis induced by buckwheat consumption (25% vs 0%, P = 0.016). Sensitization to the 22–24 kDa protein was more common in patients with buckwheat husk allergy than in those with allergy limited to buckwheat ingestion (52.9% vs. 24.1%, P = 0.048). Patients positive for the 22–24 kDa protein had significantly higher f11-sIgE levels than those who were negative (21.85 [5.19–38.05] vs 7.53 [2.84–12.95] kUA/L, P = 0.009). Multivariate logistic regression analysis further showed that sensitization to the 22–24 kDa protein was independently associated with concomitant buckwheat husk allergy ( P = 0.027, OR=5.22, 95% CI: 1.21–22.60). Conclusion Patients with buckwheat allergy may present with anaphylaxis, and respiratory symptoms upon exposure to buckwheat husks. Sensitization to the 22–24 kDa protein was associated with concomitant buckwheat husk allergy and higher f11-sIgE levels.