COMPARISON OF LEUKOCYTE EXCRETION AND BLOOD-LOSS IN INFLAMMATORY DISEASE OF THE BOWEL

Clinical relapse of inflammatory bowel disease is characterised by inc reased neutrophil migration into the intestine. The site of the neutro phil chemoattractant(s), whether luminal or mucosal, may be important since, on contact with a chemoattractant, neutrophils cause indiscrimi nate damage to their immediate surroundings by generating reactive oxy gen species and by lysosomal enzyme release. If this happens within th e mucosa, inflammation should correlate significantly with tissue dama ge as assessed by bleeding, but if it occurs within the intestinal lum en, the inflammation would be disproportionately greater than the blee ding such as is seen in classical exudation. Intestinal inflammation a nd bleeding were quantitated with the simultaneous use of indium-111 l abelled neutrophils (four day faecal excretion of indium-111) and chro mium-51 labelled red cells in patients with ulcerative colitis (n=12), Crohn's disease (n=15), and NSAID induced enteropathy (n=34). Intesti nal inflammation and blood loss correlated significantly (Spearman) in patients with ulcerative colitis (20.3% v 6.5 ml/d (median) r: 0-85, p<0.001) and NSAD enteropathy (1.6% v) 1.9 ml/d, r: 0.60, p<0.01) but not in Crohn's disease (17.0% v 2.1 ml/d, r: 0-38, p>0.1). For a given indium-111 excretion, patients with ulcerative colitis had significan tly greater (p<0.01) blood loss than patients with Crohn's disease. Th ese results suggest that the predominant site of neutrophil chemoattra ctants may be within the mucosa in ulcerative colitis and NSAID entero pathy and within the lumen in Crohn's disease.