Background: Cytokines play a predominant role in immune and inflammatory reactions in inflammatory bowel disease. Any cytokine that is produced locally as a result of gut inflammation may leak into the bowel lumen and appear in the stools. We examined the usefulness of determining cytokine profiles in the stools of patients with ulcerative colitis or Crohn's disease.

Methods: Cytokine concentrations in stool extracts were measured in 36 patients with ulcerative colitis, 32 patients with Crohn's disease, 9 controls with inflammatory disease, and 18 normal controls by means of enzyme-linked immunosorbent assays.

Results: Stool concentrations of interleukin-1beta and interleukin-1 receptor antagonist in patients with active inflammatory bowel disease increased significantly and correlated with various inflammatory factors and stool concentrations of polymorphonuclear cell elastase. The ratio of interleukin-1 receptor antagonist to interleukin-1beta in active disease was reduced significantly compared with that in inactive disease or in normal controls. Paired analysis showed a decrease in tumor necrosis factor-alpha and interleukin-1beta and interleukin-1 receptor antagonist and an increase in interleukin-4 and interleukin-10 concentrations after the resolution of disease exacerbation.

Conclusions: Measurement of cytokines in stools may be a useful and noninvasive means of understanding pathophysiology and clinical monitoring in inflammatory bowel disease.