Endogenous thrombopoietin levels during the clinical management of acute myeloid leukaemia

The Impact of Early Versus Late Platelet and Neutrophil Recovery after Induction Chemotherapy on Survival Outcomes of Patients with Acute Myeloid Leukemia

Objective:

The prognosis of patients with acute myeloid leukemia (AML) is affected by factors that are both patient- and disease-specific. The aim of this study is to evaluate the impact of early versus late platelet and neutrophil recovery after induction chemotherapy on survival outcomes of AML patients.

Materials and Methods:

A total of 181 patients with AML who were treated in our tertiary center between 2001 and 2018 were evaluated. Neutrophil and platelet recovery times were accepted as the periods from the beginning of induction chemotherapy to a neutrophil count of ≥0.5x10⁹/L and a platelet count of ≥20x10⁹/L 3 days in a row, respectively. The median time to platelet recovery was 25 days (range=12-52) for all patients. Therefore, platelet recovery in the first 25 days was defined as early platelet recovery (EPR) and at ≥26 days it was defined as late platelet recovery (LPR). The median time to neutrophil recovery was 28 days (range=13-51) for all patients. Therefore, neutrophil recovery in the first 28 days was defined as early neutrophil recovery, and at ≥29 days it was defined as late neutrophil recovery.

Results:

The 5-year overall survival (OS) rates for patients who had EPR and LPR after induction chemotherapy were 62% and 23%, respectively (p<0.001). The 5-year disease-free survival (DFS) rates for patients who had EPR and LPR after induction chemotherapy were 57% and 15%, respectively (p<0.001).

Conclusion:

Short bone marrow recovery time may indicate better healthy hematopoiesis and marrow capacity associated with longer OS and DFS.

Monoclonal anti-thrombopoietin antibodies generated by genetic immunization

Thrombopoietin (TPO) is a megakaryocyte growth and differentiation factor that is currently being investigated as a therapeutic for cancer patients undergoing myelosuppressive chemotherapy. We generated monoclonal antibodies (MAbs) specific for human thrombopoietin (hTPO) by genetic immunization using an hTPO expression plasmid and an adjuvant plasmid that encodes mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). All genetically immunized mice exhibited a high humoral immune response. Splenocytes from these mice were used to generate hybridomas. Two MAbs, designated 2B9A10 and 4C16B15 (of IgG1 and IgG3 isotypes, respectively), were subsequently selected and produced. They specifically recognized and precipitated recombinant hTPO produced by mammalian cells and were effective in sandwich enzyme-linked immunosorbent assays (ELISAs) for hTPO quantitation. Our results demonstrate that these MAbs should be useful for purification and quantitation of hTPO in clinical and laboratory settings.