Presence of Rickettsia helvetica in granulomatous tissue from patients with sarcoidosis

J Infect Dis. 2002 Apr 15;185(8):1128-38. doi: 10.1086/339962. Epub 2002 Mar 21.


In samples obtained during the autopsies of 2 patients with sarcoidosis, genetic material from Rickettsia helvetica was detected by polymerase chain reaction, and histologic and immunohistochemical examination (using 3 different antibodies) of the polymerase chain reaction-positive tissues showed different degrees of granuloma formation and presence of rickettsia-like organisms predominantly located in the endothelium and macrophages. Electron microscopic examination clearly identified and demonstrated rickettsia-like organisms within the granuloma, with findings suggestive of ongoing infection. Immunogold labeling with Proteus OX-19 antiserum showed that the gold markers were localized to the rickettsia-like organisms. Paraffin-embedded biopsy specimens from 30 patients with confirmed sarcoidosis were also reexamined, and 26 specimens were judged to be positive for rickettsia-like organisms by histologic and immunohistochemical examination. In a specimen from 1 patient, rickettsia-like organisms also were demonstrated and identified by transmission electron microscopy. These results support the hypothesis that rickettsiae may contribute to a granulomatous process, as is seen in sarcoidosis.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Biopsy
  • Female
  • Granuloma / microbiology*
  • Granuloma / pathology
  • Humans
  • Immunohistochemistry
  • Lung / microbiology
  • Lung / ultrastructure
  • Male
  • Microscopy, Electron
  • Middle Aged
  • Polymerase Chain Reaction
  • Rickettsia / isolation & purification*
  • Sarcoidosis / microbiology*
  • Sarcoidosis / pathology