Interest of anti-prothrombin antibodies and anti-phosphatidylserin/prothrombine antibodies in the assessment of a thrombosis

In the anti-phospholipid (PL) syndrome (APS), conventional research of anti-PL antibodies (Ab) is based both on the detection of cardiolipin (CL) Ab, associated or not with anti-beta 2 glycoprotein I (beta 2GPI) Ab, and/or with the demonstration of lupus anticoagulant (LAC). Other auto-Abs may be present, such as anti-phosphatidylethanolamin (PE) and the antiphosphatidylserin (PS)/prothrombin (PT) Abs. To clarify the role of the latter, we have setup three cohorts consisting of patients with thrombosis or pre-eclampsia in the first; unselected patients in whom anti-PS/PT IgG were detected in the second; and disease patient controls in the third. In the thrombotic population, anti-PS/PT IgG were found in 5.7% of the patients. When positive, anti-PS/PT IgG were associated with APS criteria in five of six cases, with anti-CL Ab and LAC but not with anti-PE Ab. The relapse risk of thrombosis is increased when anti-PS/PT IgG were present. In conclusion, anti-PS/PT Ab detection complement conventional determination (C) 2011 Elsevier Masson SAS. All rights reserved.