What are antiphospholipid antibodies?

Antiphospholipid antibodies are antibodies that interact with several inflammatory endothelial factors and disrupt the coagulation pathway; these effects can increase the risks of thromboembolism and pregnancy complications. Antiphospholipid (aPL) antibodies are additive to several traditional risk factors for thromboembolic disease (eg tobacco smoking).

Three common markers of antiphospholipid syndrome have readily available assays:

• lupus anticoagulant—not technically an antibody; the lupus anticoagulant effect is caused by aPL antibodies and is measurable in vitro
• anticardiolipin (aCL) antibody
• anti-beta2-glycoprotein I (anti-beta2-GP I) antibody.

Individual aPL antibodies and different combinations of these confer different levels of risk. The decision to screen people for aPL antibodies is usually made in hospital or by a specialist.