Characterization of the biological activity of antithrombin III in patients with hepatic cirrhosis.

A discrepancy was found in hepatic cirrhosis patients between two forms of biological activities, i.e. progressive antithrombin activity (prog AT) and heparin cofactor activity (heparin AT). A reduced level of heparin AT was obtained in comparison with that of prog AT, despite the fact that both activities correlated well in normal controls. The binding ability of AT III to heparin was observed by crossed immunoelectrophoresis, and showed a reduced second peak of AT III with a faster AT III with a qualitative defect in its binding ability to heparin due to impaired protein synthesis.