Abstract

Protein C and antithrombin III, two natural anticoagulants, play an important role in the regulation of hemostatic balance. Activated protein C (APC) and protein S complex inactivate the activated factor Va and VIIIa. Moreover, excess protein S can drive cancer cell proliferation and cell survival through oncogenic receptor Axl. Antithrombin III (ATIII) and thrombin form an inactive complex in a 1:1 molar ratio. The binding of heparin to ATIII induce conformational changes which facilitate the binding of thrombin. ATIII also inactivate factor IXa, Xa, XIa and XIIa at slow rates. At present, regarding the assay method for routine work, protein C antigen was determined by electroimmunoassay. The clotting assay was used for detecting ATIII activity (ATIII:C), ATIII antigen(ATIII:Ag) was measured using immunoassay (EIA). Assessment of protein C and ATIII has been monitoring congenital protein C deficiency and ATIII deficiency. In my detection of 20 liver cirrhosis, the results showed markedly decreased protein C antigen (PC:Ag 0.5501 vs 1.0578u/ml) and antithrombin III (ATIII:Ag 21.8 vs 39.8mg/dl, ATIII:C 40.25 vs 105.04%) respectively. The PC and ATIII assays are helpful to monitoring the liver disease and might play a predictable marker.

Keywords: Protein C, Antithrombin III, Assay methods, Congenital deficiency, Liver diseases