Innovative Cell Therapy in the Treatment of Serious Adverse Events Related to Both Chemo-Radiotherapy Protocol and Acute Myeloid Leukemia Syndrome: The Infusion of Mesenchymal Stem Cells Post-Treatment Reduces Hematopoietic Toxicity and Promotes Hematopoietic Reconstitution

Bone marrow stroma is damaged by chemotherapy and irradiation protocol. Bone marrow microenvironment supports haematopoiesis and comprises Mesenchymal Stem Cells (MSCs). Coinfusion of MSCs with hematopoietic stem cells (HSC) improves engraftment and accelerates haematopoietic recovery. Stroma-derived factor-1 (SDF-1) is a chemotactic factor which plays a crucial role in stem cell transplantation by enhancing the ability of HSC to engraft. In this study expression of SDF-1 in bone marrow MSCs and the level of Colony Forming Unit Fibroblast (CFU-F) were evaluated in 8 patients with Acute Myeloid leukemia (AML). Evaluation was done at diagnosis and after induction/consolidation chemotherapy before the onset of haematopoietic stem cell transplantation (HSCT). CFU-F frequency increases from diagnosis to remission. Nevertheless level of stromal derived factor-1 (SDF-1) transcripts in bone marrow MSCs of patients with AML stays low. Considering the role of SDF-1 in the homing of HSC, the consequences of SDF-1 deficiency observed in this study might be deleterious on the engraftment after HSCT and haematopoietic recovery. The whole result of this clinical study is an argument for MSC infusion to restore a normal level of SDF1 in the bone marrow microenvironment that could reduce hematopoietic toxicity of chemotherapy and improve HSC engraftment after HSCT. Keywords: Acute myeloid leukemia, Bone marrow microenvironment, Chemo-radiotherapy, Engraftment and haematopoietic recovery, Hematopoietic stem cells transplantation, Mesenchymal stem cells, Stromal-derived factor-1 (SDF-1).