| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1999: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
It has been suggested that microbial agents are involved in the onset of Crohn's disease. None of the candidates, however, have been unequivocally demonstrated to be causative agents. Based on clinical and immunological studies, we proposed the need of microbiology of the lymph follicle to identify causative agents in Crohn's disease. By polymerase chain reaction (PCR) using universal primers designed from conserved regions of bacterial 16S ribosomal RNA (rRNA) and subsequent DNA sequence analysis followed by a database homology search, we first confirmed the presence of bacterial 16S rRNA gene segments in human intestinal lymph follicles in 8 cases. Bacterial 16S rRNA gene segments were detected in the lymph follicle in 2 of 14 (14%) non-inflammatory bowel diseases (IBD) cases, 4 of 14 (28%) Crohn's disease cases, and in 2 of 5 (40%) ulcerative colitis cases. Nineteen 16S rRNA gene segments were recognized. Five segments showed 100% identity to known bacterial 16S rRNAs, namely staphylococcus species, Streptococcus sanguis, and Paracoccus marcusii.
However, the other 14 segments showed below 100% identity, indicating either the presence of unknown bacteria or of bacteria without known DNA data. No single identified or unidentified bacterium was characteristic for inflammatory bowel diseases. In order to clarify the etiologic significance of Mycobacterium paratuberculosis, and Listeria monocytogenes, Staphylococcus aureus (staphylococcal superantigens) in Crohn's disease, we investigated whether they could be detected in intestinal tissues, including Peyer's patches and colonic lymph follicles. Since none of tissues was positive for these bacteria, it was concluded that they were not involved in the etiology of Crohn's disease. During the process of studies, cases of intestinal infections of Listeria monocytogenes or Staphylococcus aureus was first confirmed in resected specimens of ulcerative colitis.
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