Myeloperoxidase concentrations in the stool as a new parameter of inflammatory bowel disease.

Neutrophils play a predominant role in inflammatory and immune reactions in inflammatory bowel disease. It is well established that the level of myeloperoxidase, a constituent of neutrophil azurophil granules, reflects the number of neutrophil. We examined the usefulness of determining stool levels of myeloperoxidase in patients with inflammatory bowel disease. Myeloperoxidase levels in stool extracts were measured using a radio-immunoassay in 33 patients with ulcerative colitis, 32 with Crohn's disease, 9 inflammatory disease controls and 15 normal controls. Stool levels of myeloperoxidase in active inflammatory bowel disease patients increased significantly, and correlated with laboratory parameters and endoscopic grade of inflammation. A paired analysis showed a decrease in myeloperoxidase levels after the resolution of disease exacerbation. These results suggest that stool myeloperoxidase is a simple, noninvasive, and relevant marker of disease activity.