Cross-reactivity of Tyrophagus purtescentiae with Dermatophagoides farinaeand Dermatophagoides pteronyssinus in urban areas

Background: Tyrophagus putrescentiae (TP) have cohabited with D. pteronyssi nus (DP) and D, farinae (DF) in more than 25% of houses in urban areas of K orea, and many atopic subjects have also been cosensitized to TP and Dermat ophagoides species. Objective: We evaluated the cross-reactivity of TP with DF and DP in atopic subjects of urban inhabitants. Methods: The cross-reactivity was evaluated with inhibition ELISA and immun oblotting. Allergenic components of TP were evaluated with IgE immunoblotti ng of the sera from 25 individual atopics. All enrolled subjects lived in u rban areas. Results: In ELISA inhibition with pooled sera, all TP, DP, and DF extract i nhibited TP-specific IgE by more than 90%, and the 50% inhibitory concentra tions of TP, DP, and DF extract were 0.4 mu g/mL, 0.8 mu g/mL and 0.8 mu g/ mL, respectively. The maximum inhibition, however, of DP-specific and DF-sp ecific IgE by TP extracts was 32% and 29%, respectively. With six individua l sera, the TP-specific IgE was also inhibited by more than 88% with DF ext ract in all cases. In inhibition immunoblotting, all of the TP, DP, and DF extracts completely inhibited the TP-specific IgE bands at a concentration of 2.0 mu g/mL. Fifteen allergenic components in TP were found. Among them, the 16-kD allergen was most prevalent (52%) and its IgE binding was comple tely inhibited by 0.1 mu g/mL of purified Der f2 and it also bound with 2 d ifferent monoclonal antibodies to the group 2 allergen of Dermatophagoides species. Conclusions: Our results suggested considerable cross-reactivity between TP and the two Dermatophagoides species in urban areas where TP and Dermatoph agoides species cohabit. The 16-kD allergen, which shared common epitopes w ith the group 2 allergen of Dermatophagoides, is one of the most prevalent allergens of TP.