Role of interleukin 1 in inflammatory bowel disease--enhanced production during active disease.

Interleukin 1 is a polypeptide cytokine produced by various cell types and has been shown to have a major role in inflammatory and immunological responses. In experimental colitis it proved to be a dominant mediator and a reliable marker of inflammation. The aim of the present study was to determine in vitro the extent of production and release of interleukin 1 from colonic mucosa of patients with active untreated inflammatory bowel disease. Colonic mucosal biopsy specimens were obtained during colonoscopy from 17 patients with ulcerative colitis, eight patients with Crohn's disease of the colon, and 16 normal control subjects. Interleukin 1 content was determined in fresh and 24 hour organ cultured mucosa as well as in cultured medium. Interleukin 1 content and release were significantly higher in the inflamed mucosa compared with that of control subjects. Prednisolone inhibited interleukin 1 release in a dose dependent fashion. We conclude that colonic mucosal interleukin 1 content and production is significantly raised in active inflammatory bowel disease and may have a role in the pathogenesis of the inflammatory response. Pharmacological suppression of tissue interleukin 1 production may have a beneficial therapeutic effect.