215 Study of the Allergenic Crossreactivity and Allergenic Composition of Dermatophagoides Pteronyssinus and Blomia Tropicalis

BACKGROUND: D. pteronyssinus and B. tropicalis are the most common house dust mite species worldwide. D. pteronyssinus and B. tropicalis are the most prevalent species in the tropics. Twelve allergens have been described in B. tropicalis and fifteen in D. pteronyssinus. The objectives of this study were: 1) to analyze the prevalence of sensitization to B. tropicalis and D. pteronyssinus on the tropical Island of Martinique; 2) to evaluate the allergenic crossreactivity between D. pteronyssinus and B. tropicalis and 3) to identify common, and species specific allergens, using mass spectrometry (MS). The serum of patients sensitized to a single, or to both species, was further analyzed by western blots. METHODS: The sera of 1,243 consecutive patients evaluated for allergic rhinitis and/or asthma were evaluated for specific IgE using direct ELISA. All patients resided on the tropical island of Martinique. Crossreactivity between both species was analyzed by ELISA Inhibitions. Proteins of both species were digested with trypsin and analyzed by MS/MS (MALDI TOF/TOF). Different databases were used for the identification of the proteins. RESULTS: Sensitization to B. tropicalis was detected in 868 sera and to D. pteronyssinus in 919 sera; 135 were sensitized exclusively to B. tropicalis and 177 to D. pteronyssinus. Specific IgE levels to D. pteronyssinus were significantly higher than to B. tropicalis (Mean 0.67 OD ± 0.89 vs. 0.86 ± 1.04; P < 0.001). The correlation coefficient between specific IgE levels to both species was 0.135. ELISA Inhibition studies demonstrated minimal crossreactivity between both species. Western blots done with the serum of poly or monosensitized patients revealed specific IgE binding to similar proteins. Proteomic analysis revealed the presence of the following allergens: B. tropicalis: groups 2, 3, 4, 6, 9, 14 and groups 1, 2, 3, 4, 8, 11, 14, 15, 16 and 18 in D. pteronyssinus. Species specific, as well as common proteins were detected. CONCLUSIONS: There is limited crossreactivity between B. tropicalis and D. pteronyssinus. Sensitization to their allergens seems to be a parallel phenomenon. Allergen extracts of both species are needed for the correct diagnosis and treatment of mite allergic individuals in the Caribbean.