Anti-phospholipid antibodies (APL) are a wide and heterogeneous group of immunoglobulins, whose presence defines the
anti-phospholipid syndrome (APS) in patients with arterial and venous thrombosis as well as obstetrical complications. This
syndrome was first described in 1983 by Graham Hughes as anti-cardiolipin syndrome. The term was then replaced when it
became clear that antibodies against phospholipids other than cardiolipin were also associated with clinical manifestations
of anti-phospholipid syndrome.
The anti-phospholipid syndrome is termed primary when no other underlying diseases are associated. Conversely, it is
termed secondary when it is associated with other autoimmune diseases, especially systemic lupus erythematosus (SLE).
The syndrome of acute vascular occlusion involving multiple organs occurs in a minority of patients with cardiolipin antibodies
and is defined as catastrophic anti-phospholipid syndrome.
Anti-cardiolipin test may score positive in a variety of disorders including connective tissue diseases and infectious diseases.
Evidence in clinical practice suggests that multiple and persistent anti-phospholipid positivity is associated with a more
severe course of the disease. According to the classification criteria defining anti-phospholipid syndrome, however, cardiolipin
antibodies are of clinical significance only when associated with thrombosis or recurrent pregnancy loss. Detailed clinical
information is reported in