Specificity of indium-111 granulocyte scanning and fecal excretion measurement in inflammatory bowel disease?an autoradiographic study

Abstract

The validity of¹¹¹In granulocyte scanning and fecal excretion measurement, as a reflection of loss of cells into the gastrointestinal tract, was studied using an autoradiographic technique in 11 patients in whom¹¹¹In granulocyte scan and colonoscopy were carried out simultaneously.¹¹¹In granulocytes were injected 1.5–4 hr prior to colonoscopy, and intraluminal fluid, mucosal brushings, and colonic biopsies were collected during the colonoscopy. In two patients with no histological evidence of inflammatory bowel disease, and four patients with clinically and histologically inactive inflammatory bowel disease, no¹¹¹Indium was detected in fluid, brushing, or biopsies. In five patients with active disease, 85% of the¹¹¹In activity in colonic fluid was precipitated by low-speed centrifugation. Autoradiography confirmed that the label remained attached to whole granulocytes in colonic fluid and mucosal brushings. Studies on biopsies, at intervals up to 4 1/2 hr following labeled granulocyte injection, demonstrated labeled polymorphonuclear neutrophils (PMNs) on the inflamed epithelial surface, with occasional cells in crypt abscesses by 110 min. We conclude that the techniques of¹¹¹In granulocyte scanning and fecal counting in patients with IBD are specifically measuring cell loss: labeled PMNs are capable of migrating through the gastrointestinal mucosa, in active disease, within 2 hr of administration.