Investigation of neutrophils in the gut lumen by assay of granulocyte elastase in whole-gut lavage fluid

Background: Intestinal neutrophils can be studied by radiolabelling techniques and by cytology of whole-gut lavage fluid. Our aim was to evaluate the use of a biochemical test for the presence of these cells in whole-gut ravage fluid. Method: Whole-gut lavage was performed by having the patients drink a polyethylene-glycol-electrolyte solution; the clear fluid passed per rectum after complete bowel cleansing had been collected. In 203 patients granulocyte elastase was assayed in sonicated unfiltered lavage fluid, using the specific enzyme substrate L-pyroglutamyl-L-prolyl-L-valine-p-nitroanilide. Free granulocyte elastase was also assayed in filtered (that is, cell-fret) lavage fluid in 39 of the 43 patients in whom the enzyme was present in unfiltered fluid. In 47 of the patients, cells were also separated by density gradient centrifugation, and counted. Results: Granulocyte elastase concentration correlated significantly with cell count (r = 0.80, p < 0.001). Granulocyte elastase concentration was high (> 100 nkat/l) in fluid from 25 of 68 inflammatory bowel disease patients and 6 of 135 others with radiation colitis, diverticulitis, pericolic abscess, and use of non-steroidal anti-inflammatory drugs. In patients with delectable total granulocyte elastase, cell-free granulocyte elastase was present in 11 of 29 with inflammatory bowel disease and 1 of 10 others. Conclusion: Whole-gut lavage fluid samples can readily be used to investigate Luminal inflammatory cells.