ABSTRACT
INTRODUCTION Antiphospholipid (aPL) antibodies are a wide and heterogeneous group of immunoglobulins that include, among others, lupus anticoagulants (LAs) and anticardiolipin (aCL) antibodies. LAs are acquired inhibitors of coagulation that were first described in patients with systemic lupus erythematosus (SLE). They prolong phospholipid-dependent coagulation reactions,1 but despite this in vitro behavior, LAs are not usually associated with bleeding complications. aCL antibodies react with anionic phospholipid in solid-phase immunoassays and are responsible for the biological falsepositive test for syphilis.2 LAs and aCL antibodies are closely related antibodies, and they are concurrently present in approximately two-thirds of cases.
