Anti-cardiolipin antibodies explained

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:

• 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.

Notes and References

1. Tringali GR, Julian AJ, Halbert WM . Effect of 2-mercaptoethanol treatment on anticardiolipin reactivity in sera from syphilitics and false positive reactors . The British Journal of Venereal Diseases . 45 . 3 . 202–4 . 1969 . 5346419 . 10.1136/sti.45.3.202. 1048465.
2. Hull RG . Anticardiolipin antibodies: occurrence in Behçet's syndrome . Ann. Rheum. Dis. . 43 . 5 . 746–748 . 1984 . 6497467 . 10.1136/ard.43.5.746 . 1001520 . vanc . Harris EN . Gharavi AE . 3 . Tincani . A . Asherson . R A . Valesini . G . Denman . A M . Froude . G . Hughes . G R.
3. Petri M, Golbus M, Anderson R, Whiting-O'Keefe Q, Corash L, Hellmann D . Antinuclear antibody, lupus anticoagulant, and anticardiolipin antibody in women with idiopathic habitual abortion. A controlled, prospective study of forty-four women . Arthritis Rheum. . 30 . 6 . 601–606 . 1987 . 3111489 . 10.1002/art.1780300601. free .
4. Harris EN . Anticardiolipin antibodies: detection by radioimmunoassay and association with thrombosis in systemic lupus erythematosus . Lancet . 2 . 8361 . 1211–1214 . 1983 . 6139567 . 10.1016/S0140-6736(83)91267-9 . vanc . Gharavi AE . Boey ML . 3 . Gharavi . A.E. . Patel . B.M. . Loizou . S. . Hughes . G.R.V.. 36643723 .
5. Harris EN . Crossreactivity of antiphospholipid antibodies . Journal of Clinical & Laboratory Immunology . 16 . 1 . 1–6 . 1985 . 3981615 . vanc . Gharavi AE . Loizou S . 3 . Derue . G . Chan . JK . Patel . BM . Mackworth-Young . CG . Bunn . CC . Hughes . GR.
6. Keane A, Woods R, Dowding V, Roden D, Barry C . Anticardiolipin antibodies in rheumatoid arthritis . Br. J. Rheumatol. . 26 . 5 . 346–350 . 1987 . 3664159 . 10.1093/rheumatology/26.5.346.
7. Malia RG . Anticardiolipin antibodies in systemic sclerosis: immunological and clinical associations . Clin. Exp. Immunol. . 73 . 3 . 456–60 . 1988 . 2974767 . 1541778 . vanc . Greaves M . Rowlands LM . 3 . Lawrence . AC . Hume . A . Rowell . NR . Moult . J . Holt . CM . Lindsey . N.
8. McNeil HP, Simpson RJ, Chesterman CN, Krilis SA . Anti-phospholipid antibodies are directed against a complex antigen that includes a lipid-binding inhibitor of coagulation: beta 2-glycoprotein I (apolipoprotein H) . Proc. Natl. Acad. Sci. U.S.A. . 87 . 11 . 4120–4124 . 1990 . 2349221 . 10.1073/pnas.87.11.4120 . 54059 . 1990PNAS...87.4120M . free .