Antibodies to Phosphatidylserine/Prothrombin Complex in Antiphospholipid Syndrome: Analytical and Clinical Perspectives.

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombosis and/or pregnancy-related morbidity accompanied by persistently positive antiphospholipid antibodies (aPL). Current laboratory criteria for APS classification recommend testing for lupus anticoagulant as well as IgG and IgM anticardiolipin, and beta-2 glycoprotein I (anti-β2GPI) antibodies. However, there appears to be a subset of patients with classical APS manifestations who test negative for the recommended criteria aPL tests.

Autoantibodies against phosphatidylserine, prothrombin and phosphatidylserine-prothrombin complex: identical or distinct diagnostic tools for antiphospholipid syndrome?

Background: To clarify the association and diagnostic utility of measuring antiphosphatidyl serine (aPS), antiprothrombin (aPT) and the antiphosphatidyl serine/prothrombin complex (aPS/PT) antibodies in patients with antiphospholipid syndrome (APS) and recurrent pregnancy loss (RPL).

Method: We measured IgG and IgM anti-aPS/PT (2 different kits) as well as the aPS and aPT autoantibodies by ELISA. All subjects were also tested for the presence of Lupus anticoagulant (LA), IgG and IgM anti-cardiolipin (aCL) and anti-beta-2 glycoprotein I (ass(2)GPI), and these served as the gold standard unless otherwise indicated.