IgE antibody responses to recombinant allergens of Blomina tropicalis and Dermatophagoides pteronyssinus in a tropical environment

Background: Dermatophagoides pteronyssinus and Blomia tropicalis are the major sensitizer mite species in tropical regions. Several allergens from these species have been obtained by molecular cloning. In order to use them in clinical practice, evaluation of their allergenic potential in different populations is mandatory. This study evaluates the clinical significance and allergenicity of several recombinant allergens from B. tropicalis and D. pteronyssinus in asthmatic patients from a tropical environment. Methods/Data base: Specific IgE to allergenic extracts of D. pteronyssinus and B. tropicalis and to the recombinant allergens BtM, a peptide homologue to Blo t 5, Blo t 12, Blo t 13, Der p 2, Der p 5, Der p 7, and Der p 10 as well as the natural Der p I (nDer p 1), was determined by radioallergosorbent test (RAST) in sera from 90 asthmatic patients and 10 healthy controls. In addition, SPT was performed in a selected group of patients. Results: The prevalence of reactivity to D. pteronyssinus and B. tropicalis extracts was 86.6% and 84.4%, respectively. The frequency of positive RAST to each D. pteronyssinus allergen was as follows: Der p 2, 68.9%; Der p 1, 64.4%; Der p 5, 37.8%; Der p 10, 16.7% and Der p 7, 15.6%. The frequency of positive RAST to B. tropicalis allergens was as follows: BtM, 42.2%; Blo t 12, 16.7% and Blo t 13, 11.1%. Together, Der p 1, Der p 2, and Der p 10 were able to detect 93.5% of D. pteronyssinus allergic subjects. Via skin testing, all 8 mite allergens induced positive reactions in the selected allergic patients and negative results among the nine non-allergic subjects. Conclusions: The recombinant allergens tested are potentially useful as tools for in vitro and in vivo testing of mite allergy. Together, three recombinant allergens were able to detect 93% of D. pteronyssinus allergic subjects.