title: The continuing search for Mycobacterium tuberculosis involvement in sarcoidosis: a study on archival biopsy specimens.
abstract: BACKGROUND
  Increasing evidence indicates that mycobacteria may be involved in the aetiology and pathophysiology of sarcoidosis.
  
  
  OBJECTIVE
  To investigate the association between Mycobacterium tuberculosis complex infection and sarcoidosis.
  
  
  METHODS
  Mediastinal lymph node biopsy specimens (formalin-fixed, paraffin-embedded) from 52 Danish patients with sarcoidosis, 50 patients with mediastinal lymphadenopathy of other non-mycobacterial causes (negative controls) and 12 patients with histologically and/or culture-verified mycobacteriosis (positive controls) were included in the study. Biopsy samples were analysed for the presence of Mycobacterium tuberculosis complex by strand displacement assay and a subset of specimens were examined for bacterial rRNA by fluorescent in situ hybridisation using an eubacterial probe with general bacterial specificity (EUB338).
  
  
  RESULTS
  One patient with sarcoidosis displayed a positive M. tuberculosis complex test. All negative controls were negative in the test and 5/12 patients with mycobacteriosis were positive in the test. We detected M. tuberculosis complex DNA in 10-year-old biopsy samples. Thirty-six samples were tested with the eubacterial probe; of these, 67% were positive with no difference between patients and controls.
  
  
  CONCLUSIONS
  Our results do not support the hypothesis that M. tuberculosis complex infection is involved in the pathogenesis of sarcoidosis. However, we stress the importance of excluding mycobacteriosis in the diagnostic workup of sarcoidosis patients.
authors.affiliation: Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark. clausbo@dadlnet.dk
authors.forename: Claus Bo
authors.initials: CB
authors.lastname: Svendsen
authors.forename: Nils
authors.initials: N
authors.lastname: Milman
authors.forename: Erik Michael
authors.initials: EM
authors.lastname: Rasmussen
authors.forename: Vibeke Østergaard
authors.initials: VØ
authors.lastname: Thomsen
authors.forename: Claus Bøgelund
authors.initials: CB
authors.lastname: Andersen
authors.forename: Karen Angeliki
authors.initials: KA
authors.lastname: Krogfelt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D012189:Retrospective Studies; D017565:Sarcoidosis, Pulmonary / Q000382:microbiology* / Q000503:physiopathology*; D014376:Tuberculosis / Q000382:microbiology* / Q000503:physiopathology