Comparison of rhG--CSF primed bone marrow and blood stem cell autografts: an analysis of engraftment in malignant lymphomas and solid tumours

G-CSF-primed bone marrow as a source of stem cells for allografting: revisiting the concept

The source of hematopoietic stem cells (HSCs) for allogeneic transplantation has evolved over the last decades, from the sole use of unstimulated bone marrow (BM) to the use of G-CSF (filgrastim)-mobilized peripheral blood, G-CSF-primed BM (G-BM) and cord blood. G-CSF-mobilized PBSC has replaced BM as the most commonly used source of allogeneic stem cells. G-BM is a source of HSCs, with studies demonstrating the safety and feasibility of this strategy with the potential for reducing GvHD, while retaining the speed of engraftment. Although the G-BM had lost its use as the optimal source of stem cells, after the widespread use of haploidentical transplantation, their use has resurfaced in 2010. This source can still be used in today's world of transplantation in aplastic anemia and other benign diseases, as well as in children donors. This study intends to review the evidence for this approach and whether this approach still has merit in the ever-evolving field of allogenic HSC transplantation. The merit of G-BM is its ability to offer speed of engraftment with reduced GvHD.

A randomized controlled clinical trial to determine the optimum duration of G-CSF priming prior to BM stem cell harvesting

BACKGROUND

Harvesting of hemopoietic stem cells (HSC) from G-CSF-primed BM for autologous transplantation is an alternative to collection of unprimed BM or G-CSF-primed peripheral blood (PB). However, the optimum number of days of G-CSF administration for this purpose is unknown. We set out to determine whether cell yields could be optimized by varying the number of days of G-CSF administration prior to BM stem cell harvesting.

METHODS

We conducted a randomized controlled single-center trial of 6 days (the standard) vs. 4 days of G-CSF administration and compared yields of total nucleated cells (TNC), CD34(+) HSC and CFU-GM cells per kilogram patient body weight. Statistical analysis was by Student's t-test.

RESULTS

Twenty-four patients were enrolled; 13 received 6 days and 11 received 4 days of G-CSF administration. Analysis of the first harvest aspirate showed higher proportions of CD34(+) HSC (P=0.02) and CFU-GM (P=0.03) in the 4-day group. For the 6-day and 4-day groups, respectively, the median yield of TNC/kg was 6.5 x 10(8) and 5.4 x 10(8) (P=0.28), of CD34(+) cells/kg 0.56 x 10(6) and 0.98 x 10(6) (P=0.04) and of CFU-GM cells/kg 1.66 x 10(5) and 1.55 x 10(5) (P=0.75).

DISCUSSION

These results suggest that by 6 days the HSC-stimulating effect of G-CSF has passed its peak and that 4 days should be adopted as the standard for G-CSF priming prior to BM stem cell harvesting for autologous transplantation.

Primed marrow for autologous and allogeneic transplantation: A review comparing primed marrow to mobilized blood and steady-state marrow

Mobilized peripheral blood collections, obtained following either chemotherapy (with or without granulocyte colony-stimulating factor (G-CSF)) or G-CSF administration alone, are rapidly replacing traditional bone marrow harvests as the source of cells for hematopoietic stem cell transplantation. According to the Autologous Blood and Marrow Transplant and the International Bone Marrow Transplant Registries, for the years 1998 through 2000, blood stem cell (BSC) transplants accounted for about 80% of autologous transplants in the pediatric age group and more than 90% of the autologous transplants among adults. In allogeneic transplantation, where the donor is a healthy family member or normal volunteer, G-CSF-mobilized BSC transplants are being used more and more frequently, accounting for about 20% of allogeneic transplants in the pediatric age range and more than 40% of allogeneic transplants among adults during the same time period. It is not, therefore, too great a stretch to imagine that BSC transplants will soon be, if not already, in the majority for allogeneic transplantation among adults. The principal reason why this is happening is the prevailing view that BSC engraft more rapidly than marrow stem cells (MSC). However, this view is based on comparisons between primed circulating blood cells (BSC) and unprimed resident marrow cells in the steady state (SS-MSC). If the reason why BSC engraft faster than SS-MSC were a consequence of G-CSF used for mobilization, then would priming of MSC by G-CSF (Prim-MSC) accelerate engraftment of marrow as well? We reviewed the literature of the last 10 years to see if there were enough data to answer this question.

Mobilisation of tumour cells along with CD34+ cells to peripheral blood in multiple myeloma

BACKGROUND

Cells belonging to the malignant clone are found in the peripheral blood in myeloma patients. In order to minimise the content of tumour cells in the stem cell product it is crucial to perform stem cell harvest at a time when tumour cells in the peripheral blood are at a minimum.

OBJECTIVE

The aim of the study was to compare the mobilisation kinetics of normal CD34+ cells and myeloma plasma cells during mobilisation with either G-CSF alone or high-dose cyclophosphamide (HDCy) plus G-CSF.

DESIGN AND METHODS

Morning blood samples were drawn each day during mobilisation from start of G-CSF or HDCy and to the end of leukapheresis, and were analysed by flow cytometry for content of CD34+ cells and myeloma plasma cells (CD38+ + CD45-). Tumour cells were also estimated by a patient-specific real-time polymerase chain reaction (PCR) method based on the 5' nuclease TaqMan technology.

RESULTS

Flow cytometry data from 16 patients showed concomitant mobilisation of CD34+ cells and myeloma plasma cells. Seven patients were mobilised twice; first with G-CSF alone and then with HDCy plus G-CSF. There was no difference between the two mobilisation regimens regarding tumour cell mobilisation kinetics. Real-time PCR was performed in one patient and confirmed the mobilisation of tumour cells at the time when CD34+ blood cells were at a maximum.

CONCLUSIONS

Tumour cells are mobilised to the peripheral blood at the same time as CD34+ cells in multiple myeloma patients after priming with both G-CSF alone and HDCy in combination with G-CSF.

Clinical practice and future needs in recombinant human granulocyte colony-stimulating factor treatment: a review of randomized trials in clinical haemato-oncology

Recombinant human granulocyte colony-stimulating factor (rHuG-CSF) may have a significant impact on preventing infections associated with chemotherapy-induced neutropenia, as well as shortening time to tree lineage engraftment following high-dose chemotherapy and progenitor transplantation. However, the scientific literature documenting evidence-based practice is insufficient and often misinterpreted. This review presents data and discusses the evidence for actual clinical practice in the use of rHuG-CSF in conventional cyclic chemotherapy, either prophylactic or therapeutic, and high-dose therapy, either in priming for mobilization or post-transplantation. In the past decade, many reports have based their conclusions on surrogate markers, and it is time to move towards evaluation of clinically relevant factors. Data must be generated prospectively based on current clinical practice, and several issues must be considered and evaluated to define the true clinical benefit of rHuG-CSF with or without stem-cell support. Evaluation should include complications and needs for resources as well as impact on toxicity and efficacy of conventional or high-dose chemotherapy.

Flow cytometric detection of growth factor receptors in autografts and analysis of growth factor concentrations in autologous stem cell transplantation: possible significance for platelet recovery

In order to improve prediction of hematopoietic recovery, we conducted a pilot study, analyzing the significance of growth factor receptor expression in autografts as well as endogenous growth factor levels in blood before, during and after stem cell transplantation. Three early acting (stem cell factor (SCF), Flt3 ligand (Flt3) and fetal antigen 1 (FA1)) and three lineage-specific growth factors (EPO, G-CSF and thrombopoietin (Tpo)) were analyzed by ELISA in 16 patients with multiple myeloma (MM) and 16 patients with non-Hodgkin's lymphoma (NHL). The relative number of SCF, Flt3, Tpo and G-CSF receptor positive, CD34+ progenitor cells were measured by flow cytometry in the leukapheresis product used for transplantation in a subgroup of 15 patients (NHL, n = 8, MM, n = 7). Three factors were identified as having a significant impact on platelet recovery. First, the level of Tpo in blood at the time of the nadir (day +7). Second, the percentage of re-infused thrombopoietin receptor positive progenitors and finally, the percentage of Flt3 receptor positive progenitors. On the other hand, none of the analyzed factors significantly predicted myeloid or erythroid recovery. These findings need to be confirmed in prospectively designed studies.