Thrombopoietin levels in patients undergoing autologous peripheral blood stem cell transplantation

Background and Objectives: High-dose chemotherapy with peripheral blood ste m cell transplantation (PBSCT) has become an important treatment for hemato logical and solid tumors. Several reports on endogeneous production of thro mbopoietin (TPO) in patients undergoing intensive chemotherapy have been pu blished. We measured TPO levels in patients undergoing autologous PBSCT in order to elucidate the role of TPO in megakaryopoiesis and platelet recover y following stem cell transplantation. We also examined whether PBSC from d ifferent patient groups (patients with lung cancer and malignant lymphoma) had different effects on TPO levels. Materials and Methods: Serum levels of TPO and other cytokines were determined by ELISA before and after PBSCT in 10 patients with lung cancer and 18 patients with malignant lymphoma. Resu lts: Compared to platelet counts at 1 week after transplantation, those at 3 weeks were significantly increased (p<0.001). In contrast, serum TPO leve ls were significantly decreased 3 weeks after PBSCT (p<0.01). There were no significant differences in levels of other cytokines between 1 and 3 weeks after transplantation. A strong correlation was found between serum TPO le vels and circulating platelet counts (r = -0.675; p<0.0001). Platelet count s exhibited a significant recovery and TPO levels also decreased significan tly in malignant lymphoma patients after transplantation. There were no sig nificant differences in TPO levels in lung cancer patients, although the sa me tendencies as for malignant lymphoma patients were observed for both pla telet count and TPO level. On analysis of transfused PBSC, we found that th e numbers of CFU-GM were similar in lung cancer and malignant lymphoma pati ents. However, the numbers of CD34+ cells were significantly higher in lung cancer patients than in malignant lymphoma patients. Conclusion: Our findi ngs suggest that TPO plays a critical role in the reconstitution of megakar yopoiesis and platelet production following PBSCT, and that the type of ste m cell, tumor, and preceding chemotherapy affect serum TPO levels after tra nsplantation. Copyright (C) 2000 S. Karger AG, Basel.