Gut luminal neutrophil migration is influenced by the anatomical site of Crohn's disease

Background Clinical differences between small- and large-bower Crohn's dise ase have been demonstrated. Neutrophil migration and degranulation are impo rtant effector mechanisms in gut damage. Granulocyte elastase, a neutrophil -bound enzyme, interleukin 8 and 1 beta can be detected in whole-gut lavage fluid. We aimed to assess differences between large- and small-bowel Crohn 's disease. Methods A total of 167 patients with active inflammatory bowel disease (118 Crohn's disease, 49 ulcerative colitis) underwent whole-gut lavage with a polyethylene glycol electrolyte solution. Granulocyte elastase was assayed using an enzyme substrate reaction, IL-8 and IL-1 beta by ELISA. Results Twenty-seven of 36 patients with isolated colonic Crohn's disease h ad detectable granulocyte elastase (median 0.259 mu Kat/l, range < 0.039-2. 742 <mu>Kat/l), whereas 3 of 15 with small-bowel involvement alone had dete ctable granulocyte elastase (median < 0.039 <mu>Kat/l, range < 0.039-0.266 <mu>Kat/l; P < 0.0001). Granulocyte elastase levels were significantly high er in patients with ileocolonic disease and post-ileocaecal resection compa red with small-bowel disease alone. IL-8 (P < 0.0001) and IL-1 beta (P < 0. 04) levels differed between colonic and ileal distributions. No variations were seen in ulcerative colitis. Conclusions Neutrophil migration to the gut lumen in Crohn's disease is a f eature of colonic disease irrespective of associated ileal lesions. This su ggests that bacterial-derived chemo-attractants may play a role. High level s of IL-8 in colonic disease are consistent with this hypothesis. Eur J Gas troenterol Hepatol 13:239-243 (C) 2001 Lippincott Williams & Wilkins.