Re-mobilization of peripheral blood progenitor cells within a short time interval fails to achieve effective progenitor cell yields

Abstract

Summary:We report the case of a healthy donor who was mobilized for the purpose of performing an unrelated donor transplantation with subcutaneous injections of rhG-CSF. Because of accidental loss of progenitors, 3 days after completing the first collection, the donor was mobilized again with rhG-CSF, and progenitors were collected. While a similar increase in the pre-apheresis leukocyte count was observed in both procedures, fewer mononuclear cells were mobilized during the second rhG-CSF course, resulting in a poor CD34 + yield. These data suggest that an 8-day interval between commencement of rhG-CSF mobilizations is insufficient to predict an efficient collection of hematopoietic progenitors to ensure engraftment after bone marrow transplantation. Bone Marrow Transplantation (2000) 26, 351-352. Keywords: mobilization; granulocyte colony-stimulating factor; CD34 ϩ peripheral blood progenitor cells Transplantation of recombinant human granulocyte colonystimulating factor (rhG-CSF)-mobilized peripheral blood progenitor cells (PBPCs) is now being increasingly used for the treatment of hematological malignancies and solid tumors. A 4-5 day course of 5-10 g/kg/day rhG-CSF generally allows collection of sufficient PBPCs for transplantation (Ͼ2.0 ϫ 10 6 CD34 ϩ cells/kg) by one leukapheresis in the majority of donors. This avoids the need for general anaesthesia and marrow harvest. To date, available literature on short-term second PBPC mobilization in healthy donors is limited 1-3 and, although a reduction in PBPC yield is inversely associated with time intervals between aphereses (shortest interval described between procedures of 16 days), 3 in all cases the reduction was not severe enough to prevent effective PBPC harvesting during the second mobilization. Thus, it is unclear what is the minimum period of time required to predict an adequate number of PBPCs being mobilized and subsequently collected after repeated rhG-CSF mobilization schedules.

The whys and hows of hematopoietic progenitor and stem cell mobilization

“…However, remobilization in good mobilizers to obtain a second allogeneic graft product has been described. In a single case report, retreatment with a mobilizing cytokine 3 days after completing a successful apheresis collection resulted in a poor CD34+ cell yield, 104 suggesting that a longer time period is needed before retreatment with mobilizing cytokines. This observation was confirmed in a report of 13 allogeneic donors who underwent remobilization at a median of 5 months (range 1-13 months) after the initial mobilization and the number of CD34+ cells harvested during the first and second mobilization were comparable.…”