Anti-cardiolipin antibodies

Anti-cardiolipin antibodies (ACA) are antibodies often directed against cardiolipin and found in several diseases including syphilis, antiphospholipid syndrome, livedoid vasculitis, vertebrobasilar insufficiency, Behçet's syndrome, idiopathic spontaneous abortion, and systemic lupus erythematosus(SLE). They are a form of anti-mitochondrial antibody. In SLE, The anti-DNA antibodies and anti-cardiolipin act independently. In rheumatoid arthritis w/systemic sclerosis (scleroderma) these antibodies may tie two conditions together.

Anti-cardiolipin antibodies come can be classified in two ways.

• As IgM, IgG or IgA
• As β₂-glycoprotein dependent or independent
• In autoimmune disease ACA are beta-2 glycoprotein dependent
• syphilis ACA are beta-2 glycoprotein independent and can be assayed using the Venereal Disease Research Laboratory test

Apolipoprotein H involvement

β₂-glycoprotein I has been identified as Apolipoprotein H and is required for the recognition of ACA in autoimmune disease. Only a subset of autoimmune anti-cardiolipin antibodies bind Apo-H, these anti-apolipoprotein antibodies are associated with increased thrombosis.

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