Allergenicity of the mite Hemisarcoptes corremani

Background: A researcher experienced allergic symptoms while working with the astigmatid mite Hemisarcoptes cooremani cultured on scale insects. This mite is a predator of scale insects that often parasitize many perennial vascular plants in orchards, gardens, and ornamental nurseries worldwide; therefore, orchard and ornamental nursery workers and gardeners may be exposed to this mite. Objective: We investigated the possible allergenicity of H. cooremnni and the cross-reactivity between it and other allergy-causing astigmatid mites. Methods: Serum from a subject who experienced allergic symptoms while working with H. cooremani was analyzed for IgE and IgG to proteins in an extract of this mite and of other astigmatid mites known to cause allergic reactions. The serum was used to probe proteins fractionated by SDS-PAGE or precipitated by CIE using rabbit antiserum. In addition, the subject's serum was used to directly precipitate proteins in extracts of H. cooremani and other mite species. Results: SDS-PAGE and immunoblotting of proteins in an H. cooremani extract showed the reference serum contained IgE directed at 16-kD and 19-kD proteins. Crossed radioimmunoelectrophoresis reaction showed that the subject's serum contained antibody that precipitated a protein in an H. cooremani extract and that IgE bound to this protein. The proteins in an extract of H. cooremani did not precipitate when reacted with rabbit antisera against the dust mites D. farinae, D. pteronyssinus, and E. maynei, or the storage mites B. tropicalis, L. destructor, and T. putrescentiae. This indicated there was no cross-reactivity between H. cooremani and these mites. Conclusion: These results indicated that an extract of the mite H. cooremani contained at least two prominent IgE binding proteins that were not present in the other astigmatid mites. Thus, H. cooremani is the source of unique allergenic proteins and allergy to this mite may develop in orchard and ornamental nursery workers and gardeners.