NO MYCOBACTERIUM-PARATUBERCULOSIS DETECTED IN INTESTINAL TISSUE, INCLUDING PEYERS-PATCHES AND LYMPH FOLLICLES, OF CROHNS-DISEASE

To clarify the etiologic significance of Mycobacterium paratuberculosi s in Crohn's disease, we investigated whether M. paratuberculosis was detected in intestinal tissues, including Peyer's patches, where hi. p aratuberculosis invades, and colonic lymph follicles, where early lesi ons appear. Fifty-one samples of intestinal tissues, either therapeuti cally resected or biopsied, including 34 specimens from 30 patients wi th Crohn's disease, were studied. Four Peyer's patches and eight lymph follicles were included in the intestinal tissue samples of Crohn's d isease. They were visualized by acetic acid fixation. DNA extracted fr om intestinal tissues by proteinase K treatment was used for nested po lymerase chain reaction (PCR) for detection of IS900, which is specifi c for M. paratuberculosis. PCR products were analyzed by agarose gel e lectrophoresis and subsequent Southern blot analysis. Our amplificatio n system could detect 7.5 fg of M. paratuberculosis DNA. None of the t issue samples showed positive IS900 amplification, whereas they ail sh owed amplification of the positive control human leukocyte antigen (HL A)-DQA DNA. Spiked experiments of tissue samples with M. paratuberculo sis demonstrated that inhibitors of IS900 amplification were not prese nt in the samples. Our study does not support the etiologic significan ce of M. paratuberculosis in Crohn's disease.