Serum thrombopoietin level in various hematological diseases

To investigate the pathophysioJogical role of thrombopoietin (TPO) in thrombopoiesis, we measured its serum levels in 15 healthy individuals, 87 patients with various hematological diseases and 2 patients with liver cirrhosis using an enzymeimmunoassay procedure. The TPO level was negatively correlated with the platelet count in all 104 subjects investigated. The TPO levels was 0.84 ±0.04 f mol/mL in the normal individuals. TPO levels were considerably elevated in patients with myelosuppression after intensification chemotherapy of acute leukemia in complete remission. When the data of normal individuals and patients with myelosuppression were combined as a control, TPO levels showed a significant negative correlation with the platelet count in this group (r= -0.768, p<0.0001). In aplastic anemia, acute lymphoblasuc leukemia, malignant lympnoma, multiple myeloma and chronic lymphocytic leukemia, the relationship between serum TPO levels and platelet counts was almost the same as in the control group. However, the TPO levels were slightly higher in myelpproliferative disorders, and lower in acute myelogenous leukemia, hypoplastic leukemia, myelodysplastic syndrome, liver cirrhosis and idiopaUiic thrombocytopenic purpura, when compared with the regression line for the control group. These findings suggest that TPO might play an important role in regulation of the platelet count in normal and pathological conditions.