MYCOBACTERIUM-PARATUBERCULOSIS AND MYCOBACTERIUM-AVIUM SUBSP SILVATICUM DNA CANNOT BE DETECTED BY PCR IN CROHNS-DISEASE TISSUE

Background - The etiology of Crohn's disease remains unknown. A putati ve mycobacterial cause of the disease is still controversial Aims. - T o assess the mycobacterial hypothesis in Crohn's disease using a polym erase chain reaction technique. Patients and Methods. - Nested polymer ase chain reaction with primers on the 16S-rRNA coding region (16S-rDN A) and with printers specific both to the insertion sequences (IS) 900 and IS 901/902 were used to amplify Mycobacterium paratuberculosis or Mycobacterium avium subsp, silvaticum DNA in frozen endoscopic intest inal biopsies ol surgical resection specimens from patients with Crohn 's disease (n=47: 25 endoscopic biopsies and 22 surgical resection sam ples, +/- lymph nodes), ulcerative colitis (n = 27), and non inflammat ory bowel diseases (n = 20: colonic tumors and diverticulitis). Positi ve as well as negative controls were used throughout the study. Result s. - Ail strains of Mycobacterium paratuberculosis and Mycobacterium a vium subsp. silvaticum tested were positive for both primer systems. O f the 94 biopsies tested, 5 (2 Crohn's disease, 1 ulcerative colitis a nd 2 controls) were positive with the 16S-rDNA primers but did not cor respond to Mycobacterium paratuberculosis or Mycobacterium avium subsp . silvaticum. None of the specimens was positive with the IS primers. Conclusion. - These results do not support the hypothesis that Mycobac terium paratuberculosis, or Mycobacterium avium subsp. silvaticum play a role in Crohn's disease.