ENHANCED SECRETION OF TUMOR-NECROSIS-FACTOR-ALPHA, IL-6, AND IL-1-BETA BY ISOLATED LAMINA PROPRIA MONONUCLEAR-CELLS FROM PATIENTS WITH ULCERATIVE-COLITIS AND CROHNS-DISEASE

The perpetuation of inflammation in ulcerative colitis and Crohn's dis ease may be regulated in part by an increased secretion of proinflamma tory cytokines due to either an appropriate response to initial stimul ating agents, and/or due to an impaired down-regulation of cytokine se cretion. The aim of this study was to determine the secretion patterns of the proinflammatory cytokines tumour necrosis factor-alpha (TNF-al pha), IL-6 and IL-1beta, from isolated lamina propria mononuclear cell s (LPMNC) isolated from colonic biopsies from patients with untreated ulcerative colitis or Crohn's disease. LPMNC isolated from involved in flammatory bowel disease (IBD) mucosa spontaneously produced increased amounts of TNF-alpha, IL-6, and IL-1beta. The TNF-alpha secretion fro m IBD LPMNC could be further enhanced by pokeweed mitogen stimulation. The secretion patterns of TNF-alpha and IL-1beta by LPMNC from patien ts with either ulcerative colitis or Crohn's disease demonstrated a cl ose correlation with the degree of tissue involvement and mucosal infl ammation. LPMNC from non-involved ulcerative colitis mucosa secreted m arkedly increased levels of IL-6 compared with non-involved Crohn's di sease mucosa or control mucosa. The heightened IL-6 secretion from LPM NC from non-involved ulcerative colitis mucosa without visible or micr oscopic signs of inflammation indicates that the pathophysiologic mech anisms involved in the initiation of inflammation may differ between u lcerative colitis and Crohn's disease. The determination of proinflamm atory cytokine secretion by isolated LPMNC from colonoscopic biopsies may be a sensitive method for monitoring the severity of mucosal infla mmation in IBD patients.