Lupus anticoagulant and anticardiolipin antibodies in systemic lupus erythematosus.

The lupus anticoagulant (LA) is an acquired autoantibody of the IgG or IgM type that acts on platelet factor III, inhibiting the generation of the prothrombin activator complex. It is prevalent in 5-10% of SLE cases and, in contradistinction to the name anticoagulant, it may be associated with thrombotic events, recurrent abortion or intrauterine death. Anti-cardiolipin antibody like LA, is an anti-phospholipid antibody and also causes recurrent thrombotic events. Mention has been made of a possible cross-reactivity between anti-phospholipid antibodies and anti-DNA antibodies. The optimal treatment for this problem is at present unknown.