Increased intraluminal release of eosinophil granule proteins EPO, ECP, EPX, and cytokines in ulcerative colitis and proctitis in segmental perfusion

OBJECTIVE: The role of the eosinophil granulocyte in bowel mucosa in inflam matory bowel disease still remains obscure. The present study was performed in order to elucidate the local eosinophil activity and activating cytokin es in the inflamed lesions of colon and rectum in patients with ulcerative colitis and proctitis. METHODS: The activity of intestinal eosinophils with respect to the release of granule proteins was studied in 18 patients (10 with colitis and 8 with isolated proctitis) and 18 healthy controls, using intraluminal segmental perfusion of the sigmoid colon and rectum. The released amounts of eosinoph il granule proteins: eosinophil cationic protein (ECP), eosinophil peroxida se (EPO), and eosinophil protein X (EPX) to perfusion fluid were determined by radioimmunoassays. The intraluminal release of possible eosinophil prim ing cytokines granulocyte/macrophage-colony stimulating factor (CM-CSF) and interleukin 8 (IL-8), were analyzed by immunoassays. RESULTS: The mucosal release of ECP, EPO, and EPX was increased 10- to 20-f old in patients with colitis and proctitis compared with controls. The intr aluminal release of GMCSF and IL-8, was several-fold enhanced inpatients wi th colitis and proctitis. We also found a correlation between all three eos inophil granule proteins and the levels of IL-8/GM-CSF in the sigmoidal seg ments of patients with colitis. CONCLUSIONS: We conclude that the increased release of ECP, EPO, and EPX to colorectal perfusion fluid indicate eosinophil involvement in the local di sease in patients with colitis and proctitis. IL-8 and GM;CSF may play a ro le in eosinophil accumulation and priming in colitis. (Am J Gastroenterol 1 999;94:1876-1883. (C) 1999 by Am. Coll. of Gastroenterology).