Plasma protein S-antigen (PS:Ag) in selected disease states.

Protein S is a vitamin K-dependent glycoprotein acting as a cofactor for activated protein C and thereby exerting an antithrombotic effect. When compared to values recorded in the 10 healthy normal weight normolipidemic control subjects (80.1% +/- 5.16; mean +/- SEM), plasma protein S-antigen (PS:Ag) level was found to be significantly (p < 0.01) decreased in the 11 patients with decompensated cirrhosis of the liver (54.72% +/- 4.89) and in the 12 surgical patients in critical condition (59.2 +/- 4.96), while obviously (p < 0.001) increased plasma levels were noted in the group including 20 overweight and hyperlipidemic subjects (113% +/- 3.1). Since the low PS:Ag level was associated with a decreased serum cholinesterase (CHE) activity, while both plasma PS:Ag and serum CHE activity were increased in overweight and hyperlipidemic subjects it is considered that impaired or respectively enhanced hepatic protein synthesis is at least partially responsible for changes affecting this antithrombotic plasma protein.