Crossreaction between antibodies to oxidised low-density lipoprotein and to cardiolipin in systemic lupus erythematosus.

Serum lipoproteins contain phospholipids and modified low-density lipoprotein (LDL) may thus act as a target for antiphospholipid antibodies. Raised concentrations of IgG antibodies against oxidised LDL were found in 47 of 61 (80%) patients with systemic lupus erythematosus (SLE). 46% of patients also had raised concentrations of IgG anticardiolipin antibodies. Binding of anticardiolipin antibodies to solid-phase cardiolipin was inhibited by oxidised LDL but not by native LDL in 16 of 21 sera from SLE patients. These observations suggest crossreactivity between antiphospholipid antibodies, which are closely associated with thrombosis in SLE, and antibodies to oxidised LDL, thus providing a possible link between thrombotic and atherosclerotic complications in SLE.