Nephrological and obstetric complications of the antiphospholipid syndrome.
The antiphospholipid syndrome (APS) is a disorder of hypercoagulability, characterised by thromboembolic events, repeated miscarriages and thrombocytopenia in association with circulating antiphospholipid antibodies. These antibodies are directed against epitopes on either oxidised phospholipids complexed with a glycoprotein, beta 2-glycoprotein I, or against the glycoprotein itself. Renal manifestations of the APS are varied and depend on the type of renal pathology present. The renal vasculature may be affected by either a small vessel, thrombotic microangiopathy process or by large vessel thrombosis. In patients with end stage renal disease, the prevalence of antiphospholipid antibodies may increase with time on dialysis. Anticardiolipin antibodies have been associated with a high incidence of haemodialysis access clotting, a major source of morbidity and hospitalisation in end stage renal disease patients. In renal transplant recipients, antiphospholipid antibodies may be associated with a higher incidence of primary graft non-function, particularly in patients without a history of pretransplantation haemodialysis. Complications of the APS during pregnancy span all trimesters and include intrauterine growth retardation, placental abruption, pre-eclampsia, preterm labour and recurrent fetal loss. As these women have a high risk of recurrent fetal loss, multiple treatment modalities have been investigated, including aspirin, heparin, prednisone and intravenous immunoglobulin. Various treatment strategies for the APS have been developed and are based on a combination of anticoagulant therapy with either warfarin or heparin, along with antiplatelet therapy with aspirin. Experimental treatments involving immunomodulatory therapy with intravenous immunoglobulin, apheresis and novel antibody therapy are being investigated with hopes of successful clinical applications.