Human alpha2-macroglobulin and its antitrypsic and antithrombin activities in serum and plasma

alpha2-Macroglobulin level, trypsin protein esterase and progressive antithrombin activities were measured in normal and nephrotic sera and plasma. Trypsin protein esterase activity was proportional to the alpha2-macroglobulin concentration in serum and plasma from both normal and nephrotic patients. The results were different, however, with progressive antithrombin activity: in normal plasma, antithrombin III is the main thrombin inhibitor, then alpha2-macroglobulin and alpha1-antitrypsin, whereas in nephrotic syndrome patients, alpha2-macroglobulin is the main thrombin inhibitor.