IL-8 AS AN IMPORTANT CHEMOATTRACTANT FOR NEUTROPHILS IN ULCERATIVE-COLITIS AND CROHNS-DISEASE

IL-8 is generating increasing interest as a powerful neutrophil chemoa ttractant and activator. To elucidate the mechanisms of neutrophil inf iltration in inflammatory bowel disease, we examined 33 patients with ulcerative colitis (UC), is with Crohn's disease (CD), eight with some other type of colitis, and 18 normal control subjects for measurement of IL-8 in homogenates of colonic biopsy specimens. The affected colo nic mucosa was found to contain significantly more IL-8 in patients wi th active inflammatory bowel disease than in patients with inactive di sease (UC, P < 0.001; CD, P < 0.001), in patients with other types of colitis (UC, P < 0.05; CD, P < 0.01), or in normal control subjects (U C, P < 0.001; CD, P < 0.001). Colonic IL-8 levels correlated significa ntly with the macroscopic grade of local inflammation, especially in p atients with UC (P < 0.001). Colonic IL-8 levels also correlated well with the neutrophil numbers in mucosal tissue (UC, r = 0.950, P < 0.00 1; CD, r = 0.940, P < 0.001), and with colonic IL-1 beta (r = 0.911, P < 0.001) and tumour necrosis factor-alpha (TNF-alpha) levels (r = 0.6 04, P < 0.001) in patients with these two conditions. These data sugge st a potential role for IL-8 and its regulatory cytokines IL-1 and TNF -alpha in mediating neutrophil infiltration of the gut wall in inflamm atory bowel disease.