Antiphospholipid syndrome in systemic lupus erythematosus.

Renal biopsies occasionally show a combination of thrombotic microangiopathy as a result of antiphospholipid syndrome and lupus nephritis. The thrombosis in this case preceded the onset of lupus probably by approximately 8 yr, consisting of repeated fetal loss and venous thrombosis. More severe disease may have both arterial and venous thrombotic manifestations, including pulmonary emboli and cerebrovascular lesions. The antiphospholipid syndrome bears no relationship to the class of lupus nephritis but is accompanied by more frequent and greater hypertension and greater azotemia and interstitial fibrosis, and is associated with worse outcomes than lupus nephritis without antiphospholipid syndrome.