A plasma coagulation assay for an activated protein C-independent anticoagulant activity of protein S.

Abstract

To study the physiological importance of the activated protein C (APC)-independent anticoagulant activity of protein S, we developed an assay specific for this activity. The ability of protein S to prolong the clotting time in an APC-independent way was expressed as the ratio of the clotting time in a plasma sample divided by the clotting time in the presence of a polyclonal antibody against human protein S (both after 1:1 dilution in protein S-C4BP deficient plasma). The mean protein S-dependent anticoagulant ratio (PSdAR) was 1.53+/-0.18 in 34 healthy controls, and was significantly lower in 16 heterozygous protein S deficient patients (PSdAR=1.15+/-0.09). In plasmas from patients under oral anticoagulant therapy the mean PSdAR was within the range of the control population (1.50+/-0.18). The mean total protein S antigen level in these plasmas was 58%, suggesting a higher specific APC-independent anticoagulant activity of protein S in these patients than in normals. This functional protein S assay can be used for the laboratory diagnosis of protein S deficiency, and to study the mechanism of the APC-independent anticoagulant activity in plasma.

• Authors: M van Wijnen, C van 't Veer, J C Meijers, R M Bertina, B N Bouma
• Journal: Thrombosis and haemostasis (Thromb Haemost) Vol. 80 Issue 6 Pg. 930-5 (Dec 1998) ISSN: 0340-6245 [Print] Germany
• PMID: 9869163 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anticoagulants
• Carrier Proteins
• Integrin alphaXbeta2
• Protein C
• Protein S

Topics

• Anticoagulants (pharmacology)
• Blood Coagulation Tests (methods)
• Carrier Proteins (physiology)
• Female
• Humans
• Integrin alphaXbeta2
• Male
• Protein C (physiology)
• Protein S (antagonists & inhibitors, immunology, physiology)
• Protein S Deficiency (blood, diagnosis)