ANTIPHOSPHOLIPID ANTIBODY SYNDROME - A REVIEW OF PATHOGENESIS AND TREATMENT

The manifestations of the antiphospholipid antibody syndrome are recur rent venous or arterial thrombosis, recurrent fetal loss and thrombocy topenia. Elevated antiphospholipid antibodies are usually detected as anticardiolipin antibodies (IgG or IgM isotypes) or as lupus anticoagu lants. Other assays using phospholipid antigens such as phosphatidylet hanolamine, phosphatidylinositol. phosphatidylcholine, phosphatidylser ine and phosphatidic acid have also been used, Autoimmune-related anti cardiolipin antibodies require the presence of beta(2)-glycoprotein I as cofactor. infection-related anticardiolipin antibodies do not requi re beta(2)-glycoprotein I and are not associated with thrombotic event s. Experimental mental murine models of antiphospholipid syndrome indu ced by the active or passive transfer of anticardiolipin antibodies ha ve provided evidence for the pathogenicity of these antibodies, althou gh the exact mechanism of action is unknown. Proposed mechanisms of ac tion range from their effects on platelet membranes and endothelial ce lls to their effects on components of the clotting pathway and interfe rence with trophoblastic differentiation or damage to the syncytiotrop hoblast. The main therapeutic agents for antiphospholipid antibody syn drome include platelet inhibitors, heparin, oral anticoagulants and co rticosteroids, especially in the presence of an associated rheumatic d isease. Other treatment agents include fish oil derivatives and intrav enous IgG. Low molecular weight heparins have same advantages over reg ular heparin, with possibly lower risk of complications such as bleedi ng or thrombocytopenia. Patients who experience recurrence of thrombos is while on low to moderate doses of warfarin may need to have high do sage anticoagulation, maintaining an International Normalised Ratio ab ove 2.6. The preferred initial treatment regimen in pregnant patients with antiphospholipid antibody syndrome and a history of recurrent abo rtions is a combination of aspirin (acetylsalicylic acid) and heparin. Corticosteroids plus aspirin, although equally efficacious, are assoc iated with higher risk of prematurity, maternal hypertension, gestatio nal diabetes and osteoporosis. Asymptomatic individuals with elevated antiphospholipid antibodies but without a thrombotic history do not ne ed treatment. It is, however, prudent to review these individuals regu larly for possible history of thrombotic occurrences.