Platelet-activating factor acetylhydrolase activity in intestinal mucosa and plasma of patients with Crohn's disease.

The activity of platelet-activating factor (PAF) acetylhydrolase in biopsy specimens of intestinal mucosa was compared in patients with Crohn's disease (n = 11) and controls (n = 6). In addition, PAF acetylhydrolase 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 Crohn patients than in control patients (p < 0.02), whereas there was no difference in PAF acetylhydrolase activity of colonic or jejunal samples between Crohn patients and controls. The PAF acetylhydrolase activity in the plasma of Crohn patients was significantly decreased as compared to healthy subjects. Crohn patients with high disease activity (symptomatic index > 150) had a significantly lower PAF acetylhydrolase activity in plasma, as compared to patients in clinical remission (symptomatic index < 150; p < 0.02), and as compared to healthy subjects (p < 0.001). PAF acetylhydrolase activity in plasma increased within 4 months after bowel resection (p < 0.05). These findings indicate that the PAF acetylhydrolase activity is decreased in the ileal mucosa of patients with Crohn's disease and that PAF acetylhydrolase activity in plasma 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.