Clinical analysis of thrombocytopenia in chronic dialysis patients

Thrombopoietic status in dialysis patients is controversial. This study addressed this issue by analyzing factors associated with thrombopoiesis. One hundred and fifty-one dialysis patients (119 HD and 32 CAPD) and 41 age-matched control subjects were studied. Thrombocytopenia was defined as a platelet count less than 150±109/l. Reticulated platelets (RET), a marker for marrow megakaryopoiesis, were measured using thiazole orange dye by flowcytometry. Serum thrombopoietin (TPO) level was measured by ELISA. Hepatitis C virus (HCV) antibody, platelet-associated IgG (PAIgG), and other clinical parameters were examined in the patients. The platelet counts in the HD patients were significantly lower than those in the CAPD or controls. The incidence of thrombocytopenia was 30.0 % in the HD patients. Thrombocytopenia was more prominent in the HCV-infected HD patients in whom PAIgG was mostly positive (81.8 %) and its titer was remarkably high (102.9±92.7 pg/ml). There were significant differences in the RET counts between patients with and without thrombocytopenia. None of the other parameters, such as iPTH, β2microglobulin, and Kt/V, nor any prescribed drugs were related to thrombocytopenia. Serum TPO was significantly higher in HD patients (135.9±60.1 pg/ml) than in the controls (97.0±53.4 pg/ml). In conclusion, thrombocytopenia is frequent in HD patients, especially in HCV-infected HD patients. Reduced marrow magakaryopoiesis is mostly responsible for thrombocytopenia and peripheral destruction of platelets could be, in part, involved. Mild elevation of serum TPO possibly indicates a counter-response to decreased mass of megakaryocyte in bone marrow.