OBJECTIVE: To evaluate the role of thrombopoietin (TPO) in the pathology of chronic thrombocytopenic disease. METHODS: We measured the endogenous plasma concentration of TPO in 40 patients with acquired aplastic anaemia (AA) and in 32 patients with idiopathic thrombocytopenic purpura (ITP) by a sensitive Sandwich enzyme-linked immunosorbent assay (ELISA) and compared the results. RESULTS: Plasma TPO concentrations were significantly higher in AA patients (774 +/- 393 pg/ ml) in comparison with healthy control subjects (55 +/- 34 pg/ml, P 0.05). There was also no relationship between their plasma TPO levels and platelet counts. CONCLUSIONS: TPO levels may be regulated not only by platelets but also by megakaryocytes in AA and ITP, and measurement of TPO levels is useful for diagnosing thrombocytopenia and understanding the pathophysiology of thrombocytopenia.
