PREVALENCE OF AUTOANTIBODIES AGAINST THE PLATELET GLYCOPROTEIN COMPLEXES GP IIb/IIIa, GP Ib/IX AND GP Ia/IIa IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA

Abstract

Chronic lymphocytic leukemia (CLL) is a malignant disorder characterized by the frequent occurrence of autoimmune hemolytic anemia (AIHA) and autoimmune idiopathic thrombocytopenic purpura (ITP). In this study we analyzed the presence of auto-Abs against the platelet GP complexes GP IIb/IIIa, GP Ib/IX and GP Ia/IIa in 55 consecutive CLL patients using a new antigen specific assay. All patients were simultaneously tested for anti-RBC auto-Abs with the direct antiglobulin test. Antiplatelet auto-Abs against one or more GP complexes was detected in 25 patients (45%). Anti-RBC auto-Abs were detected in 18 patients (33%), 6 of them (11%) had evidence of AIHA at the time the sample was taken. The obtained data show that platelet specific Abs develops frequently in patients with CLL, even more often than anti-RBC auto-Abs. The presence of platelet specific auto-Abs together with thrombocytopenia and normal Hb levels in 16% of patients indicated that ITP may be more common cause of thrombocytopenia in CLL than previously anticipated.