Primary, secondary, and catastrophic antiphospholipid syndrome: what's in a name?

The association of the lupus anticoagulant with thrombosis and recurrent pregnancy loss was first recognized over a 20-year period between the early 1960s and early 1980s. The introduction of the anticardiolipin test in 1983 and the recognition of its association with clinical features similar to the lupus anticoagulant led to an exponential growth of interest in this disorder. The belief that anticardiolipin antibodies and lupus anticoagulant belonged to the family of antiphospholipid antibodies led to the disorder being named the antiphospholipid syndrome (APS). Efforts by individual investigators to introduce criteria for classification of APS and to standardize anticardiolipin antibody and lupus anticoagulant tests were started in the mid-1980s to ensure more reliable recognition and treatment of affected patients. Another layer of complexity was introduced with recognition that many anticardiolipin antibody-positive sera also bound the antigen beta (2) glycoprotein I. With increasingly sophisticated epidemiologic and prospective studies in the 1990s, more structured and better-documented criteria for APS were introduced in 1999 and modified in 2006. These criteria have been widely adopted. Whereas data supporting subclassification of APS into primary and secondary subgroups remain tenuous, a small percentage of patients do appear subject to clinical features termed the catastrophic antiphospholipid syndrome. Introduction of classification criteria for APS has enabled more reliable prospective studies, the promise of better management, and more valid tests for recognition of the disorder.