title: Relationship between protein C antigen and anticoagulant activity during oral anticoagulation and in selected disease states.
abstract: Protein C is a natural vitamin K-dependent plasma anticoagulant, deficiencies of which have been found in patients with recurrent thrombosis and warfarin-induced skin necrosis. To appreciate more fully the role of protein C in disease states and during oral anticoagulation, a new functional assay for protein C involving adsorption of plasma protein C on a Ca+2-dependent monoclonal antibody, elution, quantitative activation, and assessment of plasma anticoagulant activity, has been developed. When oral anticoagulation is initiated, the anticoagulant activity of protein C decreases to a greater extent than either the amidolytic or immunologic levels. During stabilized warfarin treatment, there is no correlation between either amidolytic or antigenic levels and the functional protein C activity, suggesting that measurement of protein C anticoagulant activity may be necessary to reflect adequately the anticoagulant protection afforded by this protein. In contrast, there was a strong correlation between anticoagulant and amidolytic and immunologic levels in liver failure and disseminated intravascular coagulation. Two patients with thromboembolic disease have been identified who exhibit a marked decrease in anticoagulant activity, but who have normal immunologic and amidolytic levels. Thus, this assay permits assessment of protein C in individuals who have received anticoagulant treatment and identification of a new class of protein C-deficient individuals.
mesh_terms: D000328:Adult; D000368:Aged; D000941:Antigens / Q000032:analysis; D001777:Blood Coagulation; D002863:Chromogenic Compounds; D002908:Chronic Disease; D004151:Dipeptides / Q000378:metabolism; D004211:Disseminated Intravascular Coagulation / Q000097:blood*; D005167:Factor VII / Q000378:metabolism; D005170:Factor X / Q000378:metabolism; D006023:Glycoproteins / Q000097:blood* / Q000276:immunology; D006801:Humans; D007163:Immunosorbent Techniques; D008107:Liver Diseases / Q000097:blood*; D008875:Middle Aged; D011486:Protein C; D013924:Thrombophlebitis / Q000097:blood* / Q000188:drug therapy; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000941:Antigens; D002863:Chromogenic Compounds; D004151:Dipeptides; D006023:Glycoproteins; D011486:Protein C; D014859:Warfarin; C021129:S 2238; D005167:Factor VII; D005170:Factor X