Chemiluminescence in inflammatory bowel disease patients: a parameter of inflammatory activity.

BACKGROUND Reactive oxygen species (ROS) are produced in excess in the inflamed mucosa and peripheral blood of patients with inflammatory bowel disease. These species have emerged as a common pathway of tissue injury in a wide variety of inflammatory and other disease processes. The present study was conducted to assess ROS production and to correlate this with parameters of inflammatory activity. METHODS In 25 patients with Crohn's disease (CD), 20 patients with ulcerative colitis (UC) and 65 age- and sex-matched healthy volunteers ROS production was measured using the whole blood luminol enhanced chemiluminescence assay (LECA). Disease activity was assessed using the Crohn's disease activity index and the Ulcerative Colitis Symptoms Score (UCSS) for CD and UC, respectively. Furthermore, the effect of various scavengers, enzymes and enzyme inhibitors on LECA was studied to assess the contribution of different ROS. RESULTS LECA was significantly higher in CD and UC patients compared with healthy controls (7.1+/-4.7 and 9.8+/-6 vs. 5.2+/-2.8 x 10(3) counts per minute (cpm), p<0.05 and <0.001). In CD, relative LECA (patient/control) was correlated with the Crohn's disease activity index and C-reactive protein (CRP) (r=0.54, p=0.001 and r=0.51, p=0.01). In UC, CRP but not LECA was correlated with the Ulcerative Colitis Symptoms Score (C-reactive protein: r=0.42, p=0.01). Addition of azide, superoxide dismutase, deferoxamine and dimethylthiourea resulted in a decrease of LECA values. CONCLUSION Whole blood LECA is increased in patients with CD and UC. This parameter is correlated with disease activity in CD. The observed chemiluminescence is probably due to generation of superoxide and the hydroxyl radical.