Plasma kinin-precursor levels in clinical intestinal inflammation.

Plasma kinin-precursor (kininogen) concentrations were measured in the peripheral venous blood of 7 untreated patients with inflammatory bowel diseases, 12 healthy subjects, and 5 uncomplicated fracture cases. The mean plasma kininogen levels were significantly raised (P less than 0.025) in patients with intestinal inflammation (7.0 +/- 1.0 micrograms BK Eq/ml), as compared with the value found in healthy subjects (5.7 +/- 0.7 micrograms BK Eq/ml), and in fracture cases (5.0 +/- 1.2 micrograms BK Eq/ml). The packed cell volume did not differ (P greater than 0.05) between patients and control groups. Thus, the raised plasma kininogen levels observed in patients were not the result of nonspecific changes in plasma volume. It is suggested that raised plasma kininogen might be due to increased synthesis to provide substrate for excessive kinin-formation, to a potent inflammatory agent, or to high synthesis of acute-phase reactants. The possible significance of this observation is discussed.