PLATELET-ACTIVATING-FACTOR ACETYLHYDROLASE ACTIVITY IN INTESTINAL-MUCOSA AND PLASMA OF PATIENTS WITH CROHNS-DISEASE

The activity of platelet-activating factor (PAF) acetylhydrolase in bi opsy specimens of intestinal mucosa was compared in patients with Croh n's disease (n = 11) and controls (n = 6). In addition, PAF acetylhydr olase activity was determined in the plasma of Crohn patients (n = 30) and healthy subjects (n = 35). The activity of PAF acetylhydrolase in mucosal samples from the distal ileum was significantly lower in Croh n patients than in control patients (p < 0.02), whereas there was no d ifference in PAF acetylhydrolase activity of colonic or jejunal sample s between Crohn patients and controls. The PAF acetylhydrolase activit y in the plasma of Crohn patients was significantly decreased as compa red to healthy subjects. Crohn patients with high disease activity (sy mptomatic index > 150) had a significantly lower PAF acetylhydrolase a ctivity in plasma, as compared to patients in clinical remission (symp tomatic index < 150; p < 0.02), and as compared to healthy subjects (p < 0.001). PAF acetylhydrolase activity in plasma increased within 4 m onths after bowel resection (p < 0.05). These findings indicate that t he PAF acetylhydrolase activity is decreased in the ileal mucosa of pa tients with Crohn's disease and that PAF acetylhydrolase activity in p lasma is inversely related to disease activity in Crohn's disease. The possibility that PAF acetylhydrolase is one factor of importance for protecting the intestinal mucosa against PAF-mediated inflammation is inferred.