title: Presence of Rickettsia helvetica in granulomatous tissue from patients with sarcoidosis.
abstract: 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.
authors.affiliation: Section of Infectious Diseases, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden. knf@swipnet.se
authors.forename: Kenneth
authors.initials: K
authors.lastname: Nilsson
authors.forename: Carl
authors.initials: C
authors.lastname: Påhlson
authors.forename: Agneta
authors.initials: A
authors.lastname: Lukinius
authors.forename: Lars
authors.initials: L
authors.lastname: Eriksson
authors.forename: Lennart
authors.initials: L
authors.lastname: Nilsson
authors.forename: Olle
authors.initials: O
authors.lastname: Lindquist
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D006099:Granuloma / Q000382:microbiology* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008168:Lung / Q000382:microbiology / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000302:isolation & purification*; D012507:Sarcoidosis / Q000382:microbiology* / Q000473:pathology