Cross-antigenicity between the scabies mite, Sarcoptes scabiei, and the house dust mite, Dermatophagoides pteronyssinus.

This study demonstrated that antigens of the parasitic mite Sarcoptes scabiei (SS) cross-react with antigens of the house dust mite Dermatophagoides pteronyssinus (DP). Crossed immunoelectrophoresis (CIE) reaction of SS extract with rabbit anti-DP serum resulted in multiple immunoprecipitates. Reciprocal CIE reactions gave similar results. Immunoprecipitates from both reactions bound IgE in the sera of dust-mite-sensitive patients who had no history of scabies. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved protein/peptide bands of both SS and DP also bound serum IgE from dust-mite-allergic patients following immunoblotting. Non-allergic control sera gave no IgE binding to either SS or DP antigens. These results indicate that patients with atopy to dust mites exhibit circulating antibodies built to DP but that recognize determinants on SS antigens. It is highly probable that scabietic patients build antibodies to SS antigens that also recognize DP antigens. These results raise questions concerning the reported isotypic antibody responses to SS because the sensitivity of scabietic patients to house dust mites has not been previously evaluated. This cross-reactivity may play an important role in the susceptibility to scabies and its clinical manifestations.