Platelet kinetic studies in patients with idiopathic thrombocytopenic purpura

PURPOSE: To determine the value in diagnosis and treatment of mean platelet life, platelet production, and major sites of platelet destruction in pati ents with idiopathic thrombocytopenic purpura (ITP). PATIENTS AND METHODS: Sternal or posterior superior iliac spine bone marrow aspiration was performed in 141 patients. Platelet kinetic studies with In dium-lll tropolonate labeled autologous platelets were utilized to determin e platelet production. RESULTS: Two subgroups of patients could be defined. The first group (n = 81, 58%) had normal or increased platelet production and increased peripheral platelet destruction. These patients fulfilled the conventional criteria for ITP, including reduced platelet survival time (m ean +/- SD, 1.6 +/- 1.4 days). Forty-eight (59%) of these patients had incr eased splenic sequestration and 30 (88%) of the 34 patients who underwent s plenectomy had a complete or partial remission. The second group (n = 60, 4 2%) had decreased platelet production, with significantly greater platelet survival times (3.6 +/- 2 days, P <0.0001). In this group, the proportion o f patients with complete or partial response to splenectomy (62%) was somew hat lower (P = 0.09). These patients mainly had ineffective platelet produc tion in the bone marrow. CONCLUSIONS: Platelet kinetic studies suggest that ITP is a heterogeneous d isease that comprises two subgroups. Further studies are needed to validate these findings and to determine their effect on the choice and outcome of therapy. (C) 1999 by Excerpta Medica, Inc.