RESPIRATORY BURST OF CIRCULATING POLYMORPHONUCLEAR LEUKOCYTES AND PLASMA ELASTASE LEVELS IN PATIENTS WITH INFLAMMATORY BOWEL-DISEASE IN REMISSION

The activation of circulating polymorphonuclear leukocytes was determi ned in terms of superoxide radical generation and granulocyte elastase release in untreated patients with ulcerative colitis (N = 10) and Cr ohn's disease (N = 9) in remission and in control subjects (N = 10). S uperoxide radical generation was determined by monitoring spectrophoto metrically the reduction of ferricytochrome, after stimulation of cell s with phorbol myristate acetate. Plasma elastase concentration was me asured by a solid-phase enzyme immunoassay technique as the complex wi th alpha-1-proteinase inhibitor. Superoxide formation by polymorphonuc lear leukocytes from patients with ulcerative colitis and Crohn's dise ase was significantly lower compared with controls [median (range) nmo l/min/mg protein: Crohn's disease 7.8 (7.1-9.6); ulcerative colitis 8. 25 (7.4-10.3); controls 14.7 (13.6-15.8)] (P < 0.001), while no differ ence was found between the two groups of patients. In contrast plasma elastase levels in patients with ulcerative colitis and Crohn's diseas e were similar to that of controls. This defective respiratory burst o f polymorphonuclear leukocytes in patients with inflammatory bowel dis ease in remission, in absence of an altered degranulation, could repre sent an important factor for the pathogenesis of these diseases.