Anticardiolipin antibodies in autoimmune thrombocytopenic purpura.

Using a recently devised solid phase radioimmunoassay to detect anticardiolipin antibodies, we report the presence of these antibodies in 30 of 96 patients with chronic autoimmune thrombocytopenic purpura (AITP). IgG anticardiolipin antibody levels were elevated in 14 patients and IgM anticardiolipin antibody levels were elevated in 27 patients. We suggest that these antibodies may mediate peripheral platelet destruction by binding to phospholipids in the platelet membrane. It is also conceivable that the presence of anticardiolipin antibodies may select a subpopulation of patients with chronic AITP who may go on to develop other autoimmune disorders, such as systemic lupus erythematosus.