Human lymphocyte stimulation with pouchitis flora is greater than with flora from a healthy pouch but is suppressed by metronidazole.
OBJECTIVE
The gut flora may play an important role in the pathogenesis of inflammatory bowel disease. An ileal reservoir or pouch can be created to replace the excised rectum after proctocolectomy. In patients with ulcerative colitis this is subject to inflammation and termed pouchitis. Using bacteria from patients the authors sought evidence for the presence rather than the identity of a pathogenic species in pouchitis, and for its absence in healthy pouches by the differential effect on lymphocyte proliferation.


METHODS
An ex vivo cell culture assay was used in which peripheral blood mononuclear cells or lamina propria mononuclear cells were cultured with sterile sonicates of gut flora from patients with or without pouchitis in the presence of antigen presenting cells.


RESULTS
Sonicated pouchitis flora produced a consistent and intense proliferation of the mononuclear cells but that produced by sonicates from healthy pouches was minimal (p = 0.012 or 0.018, peripheral blood or lamina propria mononuclear cells). Preparation of the sonicates with the antibiotic metronidazole abolished their stimulatory ability (p = 0.005, peripheral blood mononuclear cells). In separate assays neither direct addition of metronidazole nor of its hydroxy metabolite affected the mononuclear cells' proliferation with alternative stimuli.


CONCLUSIONS
These results strongly support a bacterial aetiology for pouchitis.
Bell
A J G
AJ
Department of Gastroenterology, The Rayne Institute, 4th Floor Lambeth Wing, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK.
Nicholls
R J
RJ
Forbes
A
A
Ellis
H J
HJ
Ciclitira
P J
PJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D039021:Colonic Pouches / Q000382:microbiology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008795:Metronidazole / Q000494:pharmacology*; D008875:Middle Aged; D019449:Pouchitis / Q000382:microbiology*; D013010:Sonication
D000900:Anti-Bacterial Agents; D008795:Metronidazole