Circulating thrombopoietin levels in normal healthy blood donors and in aplastic anemia patients in relation to disease severity

BACKGROUND: Thrombopoietin (TPO) is the key hematopoietic growth factor regulating the production of platelets from bone marrow megakaryocytes and maintaining platelet hemostasis. This study was done to find any relationship between the levels of thrombopoietin and the severity of disease in patients with aplastic anemia. MATERIALS AND METHODS: Serum samples were collected from 52 patients with a confirmed diagnosis of aplastic anemia and 45 normal healthy blood donors of both sexes over a period of 2 years, and TPO was estimated by using commercially available TPO-specific-enzyme-linked immunosorbent assay. RESULTS: The median TPO level of 1190 pg/ml (range 625-7651 pg/ml) in aplastic anemia patients was significantly higher than the median TPO level of 121.1 pg/ml (81.25-237.7 pg/ml) in normal healthy blood donors (P = 0.000). No significant difference was observed in TPO levels of male and female patients (P = 0.453). The median TPO concentrations observed in very severe aplastic anemia, severe aplastic anemia, and nonsevere aplastic anemia were 2765 pg/ml (range 625-6451 pg/ml), 1190 pg/ml (range 672.1-7651 pg/ml), and 1111.5 pg/ml (range 761.1-2289.2 pg/ml), respectively. TPO in patients of very severe aplastic anemia was significantly higher than patients of nonsevere aplastic anemia (P = 0.043), with no significant relation among rest of the groups. DISCUSSION: TPO levels in aplastic anemia patients were significantly higher than in healthy blood donors; however, in aplastic anemia patients TPO levels were significantly higher only in patients with very severe disease.