Anti-cardiolipin antibodies
Anti-cardiolipin antibodies (ACA) are antibodies often directed against
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:
- As IgM, IgG or IgA
- As β2-glycoprotein dependent or independent
- In autoimmune disease, ACA are beta-2 glycoprotein dependent
- In syphilis, ACA[1] 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.[8] Only a subset of autoimmune anti-cardiolipin antibodies bind Apo-H, these anti-apolipoprotein antibodies are associated with increased thrombosis.