Toxic oxygen metabolite production by circulating phagocytic cells in inflammatory bowel disease

To investigate the possibility that the oxidative capacity of phagocytic cells may be defective in inflammatory bowel disease, toxic oxygen metabolite production by circulating neutrophils and monocytes has been measured by luminol dependent chemiluminescence. Neutrophils from patients with Crohn's disease and ulcerative colitis produced significantly lower chemiluminescent responses after chemotactic stimulation with formylmethionylleucylphenylalanine (fMLP) than neutrophils from control patients, p = 0.018 and 0.043 respectively. Chemiluminescent responses of neutrophils from patients with inflammatory bowel disease, however, were similar to control responses when cells were stimulated with latex beads or phorbol myristate acetate. Monocytes from patients with Crohn's disease produced significantly greater levels of chemiluminescence than control monocytes when stimulated with either fMLP (p less than 0.002), phorbol myristate acetate (p less than 0.0005) or latex beads (p less than 0.002). Monocytes from patients with ulcerative colitis also produced significantly greater levels of chemiluminescence than controls when stimulated with latex beads (p less than 0.5) or phorbol myristate acetate (p less than 0.0005), although there was no difference in the level of chemiluminescence in response to fMLP. These results exclude a generalised defect in phagocytic cell oxidase activity in inflammatory bowel disease and suggest that circulating monocytes are 'activated'.