OBJECTIVES AND METHODS The aims of the present work were to assess the presence of thrombin generation in Crohn's disease and in ulcerative colitis by using the prothrombin fragment 1 + 2 and the thrombin-antithrombin III complex assays and to study the possible relationships between these markers and disease activity. RESULTS Prothrombin fragment 1 + 2 and thrombin-antithrombin III complex were significantly raised in patients with Crohn's disease (n = 69) and with ulcerative colitis (n = 25) as compared with healthy controls (n = 50). In Crohn's disease these two markers of thrombin generation were correlated with the Van Hees index (P < 0.05 and P < 0.001, respectively); values were significantly different from controls even in the patient group displaying the lowest disease activity (P < 0.001). No correlation was found with tumour necrosis factor alpha and C-reactive protein; nevertheless patients with C-reactive protein less than or equal to 10 mg/l had significant lower values of prothrombin fragment 1 + 2 (P < 0.03). In ulcerative colitis prothrombin fragment 1 + 2 and thrombin-antithrombin III complex were significantly increased by comparison with controls, were higher in patients with pancolitis and correlated with C-reactive protein (P < 0.002 and P < 0.009, respectively). CONCLUSION These data show that prothrombin fragment 1 + 2 and thrombin-antithrombin III complex are increased in inflammatory bowel diseases and suggest that thrombin generation might be an early event in their pathogenesis.
