Virus isolation studies in Crohn's disease: a negative report.

Homogenates of gut and mesenteric lymph node tissue from patients with Crohn's disease, ulcerative colitis, and control patients were tested for cytopathic effect (CPE) production in a series of cell lines including rabbit ileal and W138 cells. A CPE was produced in W138 cells by tissue homogenates from patients with Crohn's disease, ulcerative colitis, and control patients. Evidence was obtained to suggest that this effect, although superficially similar to a viral CPE, was due to toxic protein constituents of inflamed tissue homogenate.