Objective: To examine histomorphological and immunohistological changes in an autopsy series of systemic lupus erythematosus (SLE) patients with or without anticardiolipin antibodies (aCL).
Methods: Fourteen SLE patients who died at our department from 1988 to 1996 were included. The patients' medical files were reviewed for the clinical history and the presence of IgG and IgM aCL. Autopsy samples of various organs, including regularly the kidneys, heart, brain and skin, were studied by standard histological methods and the direct immunofluorescence technique.
Results: Thirteen of 14 (93%) autopsied SLE patients were persistently positive for IgG aCL and had common overt thrombotic complications and/or other clinical features related to the antiphospholipid syndrome. Their autopsy tissue samples showed frequent occlusive vascular changes such as bland thromboses, thrombotic microangiopathy (TMA) related changes and arterial intimalfibrous hyperplasia. The immune complex related vascular changes were mostly unremarkable and present mainly in low aCL positive patients, who also had more aggressive types of lupus glomerulonephritis (GN).
Conclusion: Increased IgG aCL were found in 13 out of 14 autopsied SLE patients who had predominant occlusive vascular histopathologic changes. The coincidence of bland thromboses with a characteristic TMA histopathology suggested two pathogenetic mechanisms associated with the presence of aCL, one related to abnormal coagulation and the other to endothelial cell injury. The extent of granular vascular immune deposits, typical of SLE, and the severity of lupus GN were inversely related to the aCL level.