Cross-antigenicity between Sarcoptes scabiei and the house dust mite, Dermatophagoides farinae (Acari: Sarcoptidae and Pyroglyphidae).

Sarcoptes scabiei var. canis (L.) (SS) was shown to share a high degree of cross-reactivity with the house dust mite, Dermatophagoides farinae Hughes (DF). Sera from scabies-infested rabbits contained antibodies that recognized at least six antigens in extracts produced from DF body material and three from DF fecal material. Likewise, rabbit antiserum to DF body and DF fecal extracts contained antibodies that recognized SS antigens. Sera from control rabbits reacted with DF body and SS extracts did not show antibodies to antigens in either extract. Six of nine SS antigens were cross-reactive with DF antigens. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS—PAGE) fraction profiles of SS exhibited at least 30 protein and peptide bands. Fifteen SS bands bound DF-specific immunoglobulin E (IgE) following incubation in sera from nine DF skin-test-positive patients with no history of scabies. The IgE binding varied within and among these patients. The sera of these patients also exhibited significant IgE levels to multiple DF antigens, as demonstrated by crossed radioimmunoelectrophoresis (CRIE) and immunoblotting. Control sera from nonallergic control patients who were skin test negative to DF and without scabies exhibited no IgE binding to any SS band.