Hemocyanin is a major allergen in local mud crab Scylla paramamosain in Viet Nam

Introduction: Shellfish allergy is prevalent in coastal countries across Asia. Despite crab being a popular dish, there is limited knowledge about the features of crab allergy in Viet Nam. This study aims to identify the IgE-binding allergens in the local crab species, Scylla paramamosain (S. paramamosain). Methods: The study involved 12 patients with crab allergy and 5 subjects with crab tolerance. Each participant underwent a skin prick test (SPT) with crab extracts and was measured for specific IgE levels to crab, as well as house dust mite species Dermatophagoides farinae (DF) and Dermatophagoides pteronyssinus (DP). An immunoblot was used to identify IgE-binding proteins in S. paramamosain, followed by identification using nanoscale liquid chromatography coupled with tandem mass spectrometry analysis. Results: Patients with crab allergy exhibited higher total IgE levels (2432 ± 772.26 vs 886.15 ± 3056.74), 100% positive SPT to crab, and higher specific IgE levels to crab (3.40 ± 6.19 vs 0.48 ± 8.86) compared to subjects with crab tolerance. The level of specific IgE to crab showed significant correlation with SPT results to DP and DF (r = 0.52, P = 0.033; r = 0.82, P < 0.001, respectively). The frequencies of IgE-binding proteins in crab allergy patients were higher than in tolerant subjects. Several putative allergens were identified, including hemocyanin as a major allergen, with arginine kinase, sarcoplasmic-calcium binding protein, and triosephosphate isomerase as minor allergens. Conclusion: This study is the first to demonstrate potential molecular allergens in local mud crabs among Vietnamese individuals sensitized to house dust mites. These findings require further clinical evaluation in future studies for their application.