Measurement of Plasma Kallikrein Inhibitor Using Purified Human Plasma Kallikrein

—Comparison of Kallikrein Inhibitor, Colman's Enzyme Inhibitor and C₁INA in Various Diseases—

Abstract

Plasma kallikrein inhibitor was measured by evaluating the inhibitor activity of patients' plasma towards purified human plasma kallikrein (KABI Co.) using a chromogenic substrate S2302. And the values were compared with that of enzyme inhibitor measured by R. Colman's method in various diseases.
Normal range of kallikein inhibitor was 100±7.0% (n=5). The value was low as 61.4±8.8% (n=5) in decompensated liver cirrhosis and it was normal in compensated liver cirrhosis. It was elevated in most of the hematological malignancies except some patients with severe liver damage and of agonizing state.
The discrepancy between the kallikrein inhibitor and the enzyme inhibitor was observed in hematological malignancies, i.e. this showed low value of the enzyme inhibitor.
A good correlation between kallikrein inhibitor and C₁INA was observed (r=0.590, n=37). In some cases lowering of the kallikrein inhibitor was observed while the level of C₁INA was normal.