Clinical Significance of Serum Thrombopoietin Levels in Patients with Aplastic Anaemia

Abstract

To evaluate the clinical significance of thrombopoietin (TPO) level in diagnosis of pateints with aplastic anaemia (AA). The TPO levels in sera from 54 AA patients and 119 healthy controls were examined. A total of 92 samples were collected from AA patients including 43 samples harvested at diagnosis, 23 samples in the cytopenic period after treatment, and 26 samples of patients in partial (n=10) or complete remission (n=16) following immunosuppressive treatment. Serum TPO levels were assessed by a sandwich-antibody ELISA that utilized a polyclonal rabbit antiserum for both capture and signal. Serum samples from normal donors revealed a mean TPO level of 95.3±54.0 pg/ml, the mean TPO levels in AA sera collected at diagnosis and before onset of treatment were 2728±1074 pg/ml (P<0.001) compared with normal controls; mean platelet count at that time: 27×109/L). Serum TPO levels of AA patients in partial or complete remission after immunosuppressive treatment were significantly lower than TPO levels at diagnosis (P<0.001). However, despite normal platelet counts (mean 167×109/L), TPO levels remained significantly elevated in complete remission (mean TPO 1009±6590 pg/ml (P<0.001) compared with normal controls. There was a significant negative correlation between serum TPO levels and platelet counts in AA patients (coefficient of correlation r=-0.70, P<0.001). TPO levels are highly elevated in sera of patients with AA. Thrombopoietin did not return to normal levels in remission, indicating normal platelet count in remission of AA needs sustained high level of TPO.