Anti-cardiolipin antibodies
Anti-cardiolipin antibodies (ACA) are antibodies often directed against cardiolipin and found in several diseases, including syphilis,[1] antiphospholipid syndrome, livedoid vasculitis, vertebrobasilar insufficiency, Behçet's syndrome,[2] idiopathic spontaneous abortion,[3] and systemic lupus erythematosus (SLE).[4] They are a form of anti-mitochondrial antibody. In SLE, anti-DNA antibodies and anti-cardiolipin antibodies may be present individually or together; the two types of antibodies act independently.[5] This is in contrast to rheumatoid arthritis[6] with systemic sclerosis (scleroderma)[7] because anti-cardiolipin antibodies are present in both conditions, and therefore may tie the two conditions together.
Anti-cardiolipin antibodies can be classified in two ways:
Apolipoprotein H involvement[edit]
β2-glycoprotein I has been identified as apolipoprotein H and is required for the recognition of ACA in autoimmune disease.[8] Only a subset of autoimmune anti-cardiolipin antibodies bind Apo-H, these anti-apolipoprotein antibodies are associated with increased thrombosis.