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What is antiphospholipid syndrome?

Antiphospholipid syndrome (aPL) is an autoimmune disease in which the body produces large amounts of antiphospholipid antibodies. Phospholipids are a special type of fat containing phosphate that makes up the outer walls of the body's cells. Antiphospholipid antibodies attack the phospholipids. This causes many different problems, including increased blood clotting. Antiphospholipid syndrome was only defined in recent years and is sometimes called Hughes syndrome, or sticky blood syndrome.


It is generally characterized by the following:

  • Thrombosis—Blood clots in arteries or veins (especially in the legs); clots in vessels of the central nervous system (brain and spinal cord) can result in stroke
  • Thrombocytopenia—Low platelets (cells important in blood clotting)
  • Pregnancy loss (especially repeated losses)

Risk factors

The causes of antiphospholipid syndrome (aPL) are currently unknown, but it’s about two times more common in women than men. The disease may occur along with other autoimmune diseases, such as systemic lupus erythematosus (SLE, or lupus).

How is it diagnosed?

Antiphospholipid syndrome is often difficult to diagnose; however, blood tests for antibodies including lupus and anticardiolipin may aid in the diagnosis.

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