The Contribution of Anti-Prothrombin-Antibodies to Lupus Anticoagulant Activity--Discrimination Between Functional and Non-Functional Anti-Prothrombin-Antibodies

Thromb Haemost. 1998 Apr;79(4):790-5.


The presence of lupus anticoagulant (LAC) is strongly correlated with a history of thrombosis in patients with SLE. LAC activity can be caused by anti-prothrombin (FII)- and/or anti-beta2glycoprotein I (beta2GPI)-antibodies. In the present study, the contribution of anti-FII-antibodies to LAC activity was measured in 28 LAC positive plasmas. Plasmas were incubated with prothrombin or BSA, immobilized on CNBr-activated Sepharose, to absorb all anti-FII-antibodies. In 4 out of the 28 plasmas LAC activity was completely dependent on anti-FII-antibodies. In 7 out of the 28 plasmas, anti-FII-antibodies did not contribute to LAC activity. These anti-FII-antibodies can be regarded as non-functional antibodies. In the majority (17/28) of the samples, LAC activity within a single plasma was caused by a combination of antibodies with different specificities. Both dRVVT and KCT showed comparable sensitivity for the detection of functional anti-FII-antibodies. In conclusion, in most samples LAC activity is not caused by anti-FII-antibodies alone but by a combination of different types of antibodies. The presence of LAC activity and anti-FII-antibodies in one plasma does not automatically implicate that these antibodies are responsible for the LAC activity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibody Specificity
  • Antiphospholipid Syndrome / complications
  • Antiphospholipid Syndrome / immunology
  • Autoantibodies / immunology*
  • Autoimmune Diseases / complications
  • Autoimmune Diseases / immunology
  • Humans
  • Longitudinal Studies
  • Lupus Coagulation Inhibitor / immunology*
  • Lupus Erythematosus, Systemic / complications
  • Lupus Erythematosus, Systemic / immunology
  • Partial Thromboplastin Time
  • Prothrombin / immunology*
  • Prothrombin Time
  • Sensitivity and Specificity
  • Thrombophilia / epidemiology
  • Thrombophilia / etiology
  • Thrombophilia / immunology*


  • Autoantibodies
  • Lupus Coagulation Inhibitor
  • Prothrombin