Allergenicity of the mite, Blomia tropicalis.

Background: Blomia tropicalis (BT) occurs in a significant percentage of homes in tropical and subtropical geographic regions of the United States and Europe and in countries in South America and Asia along with the pyroglyphid mites, Euroglyphus maynei (EM), Dermatophagoides pteronyssinus, and D. farinae. Blomia species may be major sources of allergens in house dust in addition to Dermatophagoides species and E. maynei.
Methods: Crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis were used to identify the antigens and allergens of BT and to determine the cross-reactivity between BT and the house dust mites, D. farinae, D. pteronyssinus, and the stored product mite, Tyrophagus putrescentiae.
Results: Homologous crossed immunoelectrophoresis of BT resulted in 27 antigen-antibody complexes. Crossed radioimmunoelectrophoresis of these gels showed 21 different immunoglobulin E binding antigens when they were incubated in the sera from 14 patients with asthma whose radioallergosorbent test and skin test results were positive. Heterologous crossed immunoelectrophoresis reactions with BT and rabbit D. farinae body and feces, D. pteronyssinus body and feces, and T. putrescentiae body and feces antisera resulted in one to four precipitin lines. BT extract, reacted with rabbit antisera produced against the bodies of D. farinae, D. pteronyssinus, and T. putrescentiae, produced 3, 2, and 4 antigenic peaks, respectively; whereas crossed radioimmunoelectrophoresis of these gels with the sera of the 14 patients with asthma resulted in immunoglobulin E binding to 2, 2, and 4 peaks, respectively.
Conclusions: The results of this study indicated that BT contained multiple allergens of which most were species-specific. There was a limited amount of cross-reactivity between BT and the two common house dust mite species and the stored product mite. The amount of cross-reactivity appears to parallel the phylogenetic relatedness.