Dose-Adjusted Granulocyte Colony-Stimulating Factor Plus Dexamethasone Achieves More CD34+ Cell Mobilization and Earlier Engraftment in Haploidentical Hematopoietic Stem Cell Transplantation

Introduction: Previous studies have showed that higher doses of CD34+ cell were associated with more rapid neutrophil and platelet engraftment, lower probabilities of graft rejection, as well as reduced transplant-related mortality. The aim of this study was to investigate the effects of G-CSF (Filgrastim) plus dexamethasone in CD34+ cell mobilization and engraftment in T-cell replete haploidentical hematopoietic stem cell transplantation(HHSCT) which was based on G-CSF-primed bone marrow and peripheral blood graft.

Methods: A total of 79 healthy donors, who underwent bone marrow (BM) harvest and peripheral blood Stem Cells (PBSCs) collection between January 2015 and June 2019, were investigated. In G-CSF group, G-CSF was administered subcutaneously at a dose of 5μg/kg once a day from 1^st to 5^th day, while BM and PBSC were harvested on the 4^th day and 5^th day, respectively. In Dose-Adjusted G-CSF+Dex group, G-CSF was administered subcutaneously at a dose of 5μg/kg once a day on the 1^st and 2^nd day, then twice a day from the 3^rd to 5^th day; 5mg dexamethasone was injected intravenously before BM collection on the 4^th day and before PBSC apheresis on the 5^th day, respectively. All 79 recipients with hematological malignancies underwent HHSCT based on modification of BU/CY (busulfan/cyclophosphamide) and Anti-human T Lymphocyte Rabbit Immunoglobulin (ATG-F). All recipients received cyclosporine A, mycophenolate mofetil, and short-term cyclophosphamide as GVHD prophylaxis.

Results: There were no significantly statistical differences between these two groups on characteristics of both recipients and donors. In Dose-Adjusted-G-CSF+Dex group, more mono nuclear cells (MNCs) were collected from BM and PB in comparison to the cells collected in the G-CSF group (p<0.001). There was a significant difference between the two groups on CD34+ cell counts from PB (p=0.002), which led to a significant difference on CD34+ cells in mixture allografts (p=0.04). In DA-G-CSF + Dex group, more CD34+ cells achieved earlier neutrophil (p=0.001) and platelet (p<0.001) engraftment compared with G-CSF group.

Conclusion: Compared to G-CSF alone, dose-adjusted G-CSF plus dexamethasone on healthy donors can lead to more collection of MNCs and CD34+ cells in mixture allografts, which achieves earlier neutrophil and platelet engraftment.