Histopathological diagnosis of Japanese spotted fever using formalin-fixed, paraffin-embedded skin biopsy specimens: usefulness of immunohistochemistry and real-time PCR analysis.

摘要: Japanese spotted fever (JSF) is caused by Rickettsia japonica, and lethal cases are reported yearly in southwest Japan. We thus established the method of diagnosing JSF immunohistochemistry (IHC) real-time PCR (RT-PCR) using formalin-fixed, paraffin-embedded skin biopsy specimens. Two monoclonal antibodies were used for IHC, 17k genus common antigen gene served as target RT-PCR. collected (n = 61) autopsy 1) specimens from 50 patients clinically suspected JSF. Immunohistochemically, rickettsial antigens localized coarse dots cytoplasm endothelial cells macrophages. Thirty-one seropositive plus one case (group A) nine seronegative but with positive IHC and/or RT-PCR B) judged Nine regarded non-JSF disorders based on negative serology, C). Of biopsies (eschar 34, eruptions 10, scabs 6) groups A B, positivities 94% (32/34) 62% (21/34) eschar, 80% (8/10) 30% (3/10) eruptions, 33% (2/6) 50% (3/6) scabs. For eschar was most suitable, insufficient. Unexpectedly, 18 happened to be fixed 100% formalin, this lowered detection rate RT-PCR, tolerant. Sequence analysis five confirmed a 114 bp DNA stretch homologous that R. japonica. In 26 (84%) 31 patients, diagnosis made earlier than serology.