Pathogenic Yersinia DNA is detected in bowel and mesenteric lymph nodes from patients with Crohn's disease.

Previously, we detected pathogenic (invasive) DNA in the appendices of two patients who later developed Crohn's disease (CD). This subsequent investigation is the first to evaluate a series of specimens from CD patients for the presence of pathogenic DNA. A total of 54 intestinal resection specimens from 52 patients with confirmed CD were evaluated. Lesional tissue was tested by polymerase chain reaction analysis for the presence of genes occurring only in pathogenic Primer pairs are specific for each species, with no known cross reactions with other bacteria. Forty normal bowel specimens, 30 cases of acute appendicitis, and 50 cases of various active colitides served as disease controls. Medical records were reviewed following polymerase chain reaction and histologic evaluation. A total of 17 of 54 resections (31%) contained DNA by polymerase chain reaction. Mesenteric lymph nodes were also positive in eight of these cases. All controls were negative. -positive patients had carried the diagnosis of CD for a median of 10 years before resection (range 1 month to 40 years). We report the first documentation of DNA in a series of CD cases. Further studies are needed, including serial study, over time, of -positive CD patients, as well as prospective studies of newly diagnosed CD patients for evidence of infection. Like previous studies associating infectious organisms with CD, much work remains to elucidate whether the presence of DNA is an epiphenomenon or actually a factor in the pathogenesis of CD.