Luminal neutrophil migration in ileoanal pouches studied by whole gut lavage

Objective. White cell scintigraphy has shown that neutrophils migrate into the gut wall and lumen in ileoanal pouches. We aimed to establish whether whole gut lavage fluid can be used to investigate intestinal neutrophil migration in ileoanal pouches. Design. A prospective single centre study recruiting consecutive patients. Methods. Whole gut lavage with polyethylene glycol electrolyte solution was performed in 56 (32 men, 24 women) ileoanal pouch patients who had undergone colectomy for ulcerative colitis; the first clear effluent was collected, processed and stored at -70°C. The fluid was assayed for neutrophil granulocyte elastase using a specific colorimetric assay, IgG, albumin, α1-antitrypsin, haemoglobin and cytokines IL-1β and IL-8 using previously described techniques. Patients' disease activity was characterized following pouchoscopy and biopsy. Results. Patients with pouchitis had significantly higher levels of granulocyte elastase in whole gut lavage fluid compared with those without pouchitis. Patients with detectable granulocyte elastase had higher pouchoscopy score, more severe mucosal neutrophil infiltration and protein loss and bleeding. These patients had significantly higher levels of cytokines IL-1β and IL-8 in the whole gut lavage fluid, compared with patients with undetectable granulocyte elastase. Conclusion. Whole gut lavage fluid samples may provide a useful investigative tool to study mucosal inflammation and luminal neutrophil migration in ileoanal pouches.