Cross-Reactivity between Scylla paramamosain and Dermatophagoides farinae : Identification of Tropomyosin and Arginine Kinase as Major Cross-Reactive Allergens

Scylla paramamosain and Dermatophagoides farinae are dominant allergen sources in Asia, yet the molecular basis of their cross-reactivity remains poorly defined. Among 385 HDM-positive sera, 13.5% exhibited IgE reactivity to S. paramamosain extract, demonstrating serological cosensitization between crustacean and mite in southeastern China. Four homologous allergen pairs, namely, tropomyosin (TM), arginine kinase (AK), troponin C (TnC), and triosephosphate isomerase (TIM), shared >50% sequence identity and were all cross-recognized by IgG on Western blot. Basophil activation testing nevertheless distinguished the pairs functionally, as TM and AK activated basophils in 95% and 88% of cross-reactive patients, whereas TnC and TIM did not reach statistical significance at the group level. AK, conventionally ranked below TM in crustacean allergy, therefore, contributes almost equally to cross-reactivity. Cross-inhibition ELISA further demonstrated directional asymmetry in IgE cross-reactivity, and eight and nine conserved B-cell epitope regions were mapped on TM and AK. These findings clarify the allergen basis of crab-mite cosensitization and support AK-inclusive component-resolved diagnosis.