Co-sensitization and cross-reactivity of Blomia tropicalis with two Dermatophagoides species in Guangzhou, China.

Background Contradictory results have been reported previously in the analyses of cross-reactivity among Blomia tropicalis (Blo t), Dermatophagoides pteronyssinus (Der p), and Dermatophagoides farinae (Der f). This study aims to investigate the characteristics of co-sensitization and the IgE cross-reactivity among them and attempts to identify whether patients are sensitized to Blo t due to cross-reaction or true sensitization. Methods Specific IgE (sIgE) in the sera from 1497 allergenic patients was determined by ImmunoCAP. Cross-reactivity was analyzed and determined by sIgE inhibition with 21 sera samples. Results Around 85.50% of patients were sensitized to Der p, 85.37% of patients were sensitized to Der f, and 71.54% of patients were sensitized to Blo t. Further, 70.14% of patients were co-sensitized to Blo t, Der p, and Der f, and only seven patients were sensitized solely to Blo t. With increasing sIgE levels for Blo t, the positive rates of severe-level (class 5-6) co-sensitization to Der p or Der f significantly increased. Blo t was moderately associated with Der p and Der f, with correlation coefficients of 0.6998 and 0.6782, respectively. Der p and Der f inhibited IgE binding to Blo t more strongly than Blo t inhibited IgE binding to Der p or Der f in the patient groups C-Blo t Dermatophagoides species (Der p and Der f) and helps to provide adequate diagnosis and treatment of the mite-allergic patients.