Anticardiolipin Antibodies

• Anticardiolipin Antibodies, IgA, Quantitative (161836)
• Anticardiolipin Antibodies, IgG, Quantitative (161810)
• Anticardiolipin Antibodies, IgM, Quantitative (161828)
• Anticardiolipin Antibodies, IgG, IgM, Quantitative (161802)
• Anticardiolipin Antibodies, IgA, IgG, IgM,Quantitative (161950)

The first anticardiolipin antibody (ACA) tests were developed in the early 1900s as a screening test for syphilis.¹ The Venereal Disease Research Laboratory (VDRL) test is a manual agglutination assay that detects antibodies to cardiolipin extracted from bovine heart tissue. Mass screening studies with the VDRL revealed that this test was not specific for syphilis. False-positive VDRL screening results were found to be significantly associated with lupus anticoagulants and risk of thrombosis. The first solid-phase immunoassays for antibodies to cardiolipin were developed in the early 1980s. These assays, designed to detect anticardiolipin IgA, IgG, and IgM isotypes, are approximately 100-fold more sensitive than the classical VDRL assay.¹ The presence of anticardiolipin antibodies (especially those of moderate to high titer for IgG) is strongly associated with both arterial and venous thrombosis and recurrent pregnancy loss.^2-4 The IgM and IgA isotypes of anticardiolipin antibody have also been shown to be associated with venous thrombosis.^2,3,5 The distribution of isotypes of anticardiolipin antibody-positive patients with thrombosis has been found to be as follows:²

 

IgG	36%
IgM	17%
IgA	14%
Multiple	33%

In general, anticardiolipin antibodies are considered to be more sensitive than lupus anticoagulants for APS and are implicated in approximately five times more cases.^2,3

• At least one anticardiolipin antibody isotype can be detected in 80% to 90% of patients with APS.⁶
• Approximately 90% of individuals with lupus anticoagulants will also be positive for at least one isotype of anticardiolipin antibody.⁵

Lupus anticoagulants are more specific for APS than anticardiolipin antibodies.^2,6

• The specificity of anticardiolipin antibodies for APS is increased with higher titer, especially for the IgG isotype.^1,3

While there is frequent concordance between lupus anticoagulant and anticardiolipin antibody results, clinical situations occur in which one is present in the absence of the other.^1,6

References

1. Levine JS, Branch DW, Rauch J. The antiphospholipid syndrome. N Engl J Med.2002 Mar 7; 346(10):752-763. PubMed 11882732

2. Bick RL. Antiphospholipid thrombosis syndromes. Clin Appl Thromb Hemost. 2001 Oct; 7(4):241-258. PubMed 11697705

3. Carreras LO, Forastiero RR, Martinuzzo ME. Which are the best biological markers of the antiphospholipid syndrome? J Autoimmun. 2000; 15(2):163-172. PubMed 10968904

4. Reddel SW, Krilis SA. Testing for and clinical significance of anticardiolipin antibodies. Clin Diagn Lab Immunol. 1999; 6(6):775-782. PubMed 10548562

5. Alving BM. The antiphospholipid syndrome: Clinical presentation, diagnosis, and patient management. In Kitchens CS, Alving BM, Kessler CM, eds. Consultative Hemostasis and Thrombosis. Philadelphia, Pa: WB Saunders; 2002:181-196.

6. Harris EN, Pierangeli SS, Gharavi AE. Diagnosis of the antiphospholipid syndrome: A proposal for use of laboratory tests. Lupus. 1998; 7(Suppl 2):S144-S148. PubMed 9814693