ANTIPHOSPHOLIPID SYNDROME Antiphospholipid syndrome (APS) is often associated with systemic lupus erythematosus (SLE) (20%–30%) and rheumatoid arthritis (RA). The main APS antibodies are the lupus anticoagulant, anti-beta-2-glycoprotein, and anticardiolipin. APS predisposes to both arterial and venous thrombi formation and spontaneous abortion (particularly associated with anticardiolipin antibodies). Laboratory testing shows a paradoxically prolonged PTT (only thrombophilia with an abnormality in the PTT).
