Lupus anticoagulant--antiphospholipid antibodies and thrombophilia. Relation to protein C--protein S--thrombomodulin.
In order to define the behavior of the lupus anticoagulant and/or antiphospholipid antibodies, we investigated the possible association with protein C, protein S and thrombomodulin. In 19 patients with established diagnosis of an autoimmune disease and coexisting lupus anticoagulant protein C (antigen and activity), protein S (total and free), anticardiolipin and antiphosphatidylserine antibodies were estimated. In one case the IgG globulin fraction containing the inhibitor was separated. The activation rate of pure protein C to its activated form using thrombin/thrombomodulin as activator was then measured in the presence or absence of lupus anticoagulant. No overall decrease of protein C or protein S was detected in patients' plasma. Nevertheless, the lupus anticoagulant had a specific effect on the protein C system, inhibiting the catalytic activity of thrombomodulin without causing a functional protein C deficiency. This specific effect upon thrombomodulin can be a main cause, but not necessarily the only one, for the thrombophilic tendency of patients with the lupus anticoagulant.
Tsakiris
D A
DA
Coagulation and Fibrinolysis Laboratory, Kantonsspital, Basel, Switzerland.
Settas
L
L
Makris
P E
PE
Marbet
G A
GA
D000906:Antibodies / Q000276:immunology* / Q000502:physiology; D001779:Blood Coagulation Factors / Q000276:immunology* / Q000502:physiology; D005260:Female; D006023:Glycoproteins / Q000172:deficiency / Q000276:immunology / Q000502:physiology; D006801:Humans; D016682:Lupus Coagulation Inhibitor; D008297:Male; D010743:Phospholipids / Q000276:immunology* / Q000502:physiology; D011486:Protein C / Q000276:immunology / Q000502:physiology; D020151:Protein C Deficiency; D017293:Protein S; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000276:immunology / Q000502:physiology; D018179:Receptors, Thrombin; D013927:Thrombosis / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology
D000906:Antibodies; D001779:Blood Coagulation Factors; D006023:Glycoproteins; D016682:Lupus Coagulation Inhibitor; D010743:Phospholipids; D011486:Protein C; D017293:Protein S; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin