Serum thrombopoietin level after allogeneic bone marrow transplantation: possible correlations with platelet recovery, acute graft-versus-host disease and hepatic veno-occlusive disease. Nagoya Bone Marrow Transplantation Group.

Thrombopoietin (TPO) is a growth and differentiation factor for megakaryocytes and platelets. An ELISA was developed for measuring TPO concentrations in human sera. The mean +/- S.D. of TPO level obtained in 29 control subjects was 0.87 +/- 0.35 fmol/ml. We measured the TPO level in 36 patients after allogeneic bone marrow transplantation (BMT) and determined the relationship between blood levels of TPO and changes in the circulating platelet mass. In general, a reciprocal relationship was observed between TPO and platelet count (r = -0.609, P < 0.0001; n = 165). With the decrease in the platelet mass after myeloablative therapy, the TPO level increased proportionally and peaked during the platelet nadir. The peak concentration of TPO ranged from 20-50 fmol/ml. The TPO level decreased with the normalization of the platelet mass. In contrast, the TPO level decreased during acute graft-versus-host disease (GVHD) in several patients. Furthermore, the TPO level was significantly lower in the patients with hepatic veno-occlusive disease (VOD) than in the patients after BMT without GVHD and VOD in the samples of less than 50000/microliters platelets (P < 0.005). These findings suggest that in the patients given allogeneic BMT, TPO has an important role in the physiologic regulation of platelet production and that liver damage due to acute GVHD and VOD may decrease the TPO level.