The anti-phospholipid antibody syndrome: clinical and serological aspects

The association of thromboses and/or cytopenias with anti-phospholipid anti bodies (aPL), the anti-phospholipid syndrome (APS), is well recognized. The syndrome may be primary or occur within systemic lupus erythematosus (SLE) . The notion of the syndrome occurring within SLE is important since patien ts found to have aPL may be at risk for developing APS manifestations, thos e who develop some manifestations may be at risk for developing others and, finally, SLE patients with this syndrome may need special treatment. There are subtle differences between the primary and the secondary forms, mostly due to the frequently higher and more persistent autoantibody levels in th e primary and the influence of lupus in the secondary. These syndromes may be related to various antigen/antibody systems in which phospholipids parti cipate either directly or through their effect on the proteins that bind th em. Similar clinical manifestations also occur in patients who have serum a ntibodies to such proteins (e.g. beta(2)-glycoprotein-1) in the absence of phospholipid. Some of these antibodies may even be more important pathogeni cally than the antibodies against cardiolipin that were originally describe d. Testing for the latter is, however, still the first choice when suspecti ng an antiphospholipid syndrome. If this is negative in this situation, a s earch for the other autoantibodies is indicated.