What are the subtypes of antiphospholipid syndrome (APS)?

Updated: Nov 24, 2020
  • Author: Suneel Movva, MD; Chief Editor: Herbert S Diamond, MD  more...
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Multiple terms for APS exist. Unfortunately, some synonyms can be confusing. Lupus anticoagulant (LA) syndrome, for example, is misleading—first, because patients with APS may not necessarily have systemic lupus erythematosus (SLE), and second, because although LAs do have an anticoagulant effect in vitro, LA syndrome manifests clinically with thrombotic rather than hemorrhagic complications. In an attempt to avoid further confusion, APS is currently the preferred term for the clinical syndrome.

Some patients with APS have no evidence of any definable associated disease, while, in other patients, APS occurs in association with SLE or another rheumatic or autoimmune disorder. Traditionally, these have been referred to as primary or secondary APS, respectively. Currently, however, the preferred terminology is APS with or without associated rheumatic disease. Although antiphospholipid (aPL) antibodies are clinically linked to APS, whether they are involved in the pathogenesis or are an epiphenomenon is unclear. (Up to 5% of healthy individuals are known to have aPL antibodies.)

The development of aPL antibodies has been described in association with thrombosis in patients with COVID-19, and in a cohort study from France, lupus anticoagulant was detected in a large percentage of patients with severe COVID-19. However, it is not yet known whether the aPL antibodies in these patients play a role in COVID-19–associated thrombosis or merely represent an association. [2]

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