Prevalence of secondary hematologic disorders in the antiphospholipid syndrome: impact on coagulation risk.

Hematologic abnormalities may occur in antiphospholipid antibody syndrome. The most common of these abnormalities is thrombocytopenia. The mechanism by which low platelet counts occur is not known but studies continue to elucidate the potential role of autoantibodies and cell surface markers. The risk for thrombosis in patients with thrombocytopenia does not appear to be related to the presence of thrombocytopenia itself. Innovative treatment with anti-CD20 antibodies may be of benefit in reversing thrombocytopenia and treatment with splenectomy does not appear to increase the risk for subsequent thrombosis. Hemolytic anemia is associated with antiphospholipid antibodies as well, but the risk for thrombosis in patients with hemolytic anemia is not clearly elevated. Diagnostic features of disseminated intravascular coagulation may co-occur with the antiphospholipid syndrome and may be associated with a catastrophic clinical presentation.