The use of granulocyte colony-stimulating factor in volunteer blood and marrow registry donors

A review of the genetic and long-term effects of G-CSF injections in healthy donors: a reassuring lack of evidence for the development of haematological malignancies

In 2007 the WMDA responded to the publication of two manuscripts suggesting a causal link between G-CSF and myeloid malignancies in healthy donors by convening an international symposium to examine this issue. At the time, registries reviewed the long-term follow-up of their healthy donors, which suggested no excess of leukaemia in PBSC donors compared with BM donors. Although the evidence for an increased risk of malignancy in healthy donors was felt to be weak, it could not be excluded. The WMDA, therefore, issued a statement, to be included in all donor consent forms, stating that it was unknown whether G-CSF increased or decreased the risk of later developing cancer. In 2012, with 5 years of additional donor follow-up and the results of several genetic studies now available, the clinical working group of the WMDA again reviewed the data. On the basis of an assessment of a continuing lack of evidence for an increased risk of malignancy in donors receiving G-CSF, the WMDA has re-issued a more reassuring statement. The revised statement was circulated to all WMDA member registries in late 2012 to replace the existing statement in consent forms, which now conclusively states that, 'Studies following large numbers of unrelated donors have shown that the risk of developing cancer within several years after the use of G-CSF is not increased compared with donors not receiving G-CSF'. Herein we review the evidence on which this statement is based.

Safety and efficacy of healthy volunteer stem cell mobilization with filgrastim G-CSF and mobilized stem cell apheresis: results of a prospective longitudinal 5-year follow-up study

BACKGROUND AND OBJECTIVES

G-CSF-mobilized peripheral blood stem cells have long replaced marrow as the major source for allogeneic transplants. Conclusive evidence questioning the long-term safety of G-CSF for donors has not been provided, but the cumulative number of followed donors remains insufficient to rule out rare adverse events. A long-term active follow-up study of G-CSF-mobilized healthy volunteer donors was therefore performed.

PATIENTS AND METHODS

Two hundred and three successive donors were evaluated pre-apheresis, subjected to G-CSF-mobilization/apheresis, and actively followed for 5 years by the same physicians and laboratories. Follow-up laboratory work included standard biochemical/haematological tests and T-cell phenotyping.

RESULTS

Donor epidemiology was typical for reported stem cell donor cohorts. Acute adverse effects of G-CSF and apheresis were mild and transient, consistent with the previous reports. Mean circulating CD34(+) cells after nine doses of G-CSF were 124 per μl. Other biochemical/haematological parameters were also altered, consistent with G-CSF treatment. Spleen enlargement was modest. At first follow-up, all clinical and laboratory parameters had normalized. Leucocyte/lymphocyte counts and CD4/CD8 ratios were the same as during premobilization work-up and remained unchanged throughout. A single severe but likely unrelated adverse event, a case of papillary thyroid carcinoma, was reported.

CONCLUSION

The studies add an observation time of almost 500 donor years to the growing body of evidence of the long-term safety of G-CSF for allogeneic donor stem cell mobilization.

Effects of granulocyte-colony stimulating factor on chromosome aneuploidy and replication asynchrony in healthy peripheral blood stem cell donors

As peripheral blood has surpassed bone marrow as a predominant source of stem cells for transplantation, use of the cytokine granulocyte colony-stimulating factor (G-CSF) to mobilize peripheral blood stem cells (PBSCs) is increasing. Issues regarding potential genotoxic effects of even short-term, low-dose G-CSF treatment for the healthy donors have been raised. To address the question of chromosomal instability, we used FISH to evaluate the peripheral blood lymphocytes of 22 PBSC donors and 22 matched controls at 5 time points over a 12-month period. The specimens obtained were a pre-G-CSF, followed by collections at the time of PBSC harvest (days 5-7) and at 2, 6, and 12 months after donation. Eight additional PBSC donors provided a single sample at 12 months. Nine loci (mapped to chromosomes 7, 8, 9, 17, 21, and 22) were evaluated for aneuploidy, including 3 mapped to chromosome 7 because of the specific relevance of monosomy 7. Replication timing was evaluated for chromosome 15 and 17 loci. No evidence was found of G-CSF-induced chromosomal instability. This work supports the epidemiologic data that have demonstrated no increased risk for hematologic malignancies in G-CSF-primed PBSC donors.

Immunohematopoietic stem cell transplantation in Cape Town: a ten-year outcome analysis in adults

BACKGROUND AND OBJECTIVES

Immunohematopoietic stem cell transplantation has curative potential in selected hematologic disorders. Stem cell transplantation was introduced into South Africa in 1970 as a structured experimental and clinical program. In this report, we summarize the demography and outcome by disease category, gender, and type of procedure in patients older than 18 years of age who were seen from April 1995 to December 2002.

PATIENTS AND METHODS

This retrospective analysis included 247 individuals over 18 years of age for whom complete data were available. These patients received grafts mostly from peripheral blood with the appropriate stem cell population recovered by apheresis.

RESULTS

Patient ages ranged from 20 to 65 years with a median age of 42 years. There were 101 females and 146 males. There were no withdrawals and 63% survived to the end of the study. At 96 months of follow-up, a stable plateau was reached for each disease category. Median survival was 3.3 years (n=6, 14.6%) for acute lymphoblastic anemia, 3.1 years (n=44, 18%) for acute myeloid leukemia, 2.8 years (n=47, 19%) for chronic granulocytic leukemia, 2.8 years (n=71, 29%) for lymphoma, 1.5 years (n=23, 9%) for myeloma, 1.43 years (n=10, 4%) for aplasia, and 1.4 years (n=38, 15%) for a miscellaneous group comprising less than 10 examples each. Multivariate analysis showed that only diagnosis and age had a significant impact on survival, but these two variables might be interrelated. There was no significant difference in outcome by source of graft.

CONCLUSION

The results confirm that procedures carried out in a properly constituted and dedicated unit, which meets established criteria and strictly observes treatment protocols, generate results comparable to those in a First World referral center. Low rates of transplant-related mortality, rejection and graft-versus-host disease are confirmed, but the benefits cannot be extrapolated outside of academically oriented and supervised facilities.

Granulocyte transfusions in neutropenic patients: beneficial effects proven?

Despite the huge armamentarium of modern antibiotics and anti-fungals, infections remain life-threatening events in patients with profound neutropenia. For decades, the value of granulocyte transfusions (GT) has been explored and results are still not conclusive. However, it has been shown that GT increase peripheral blood neutrophil counts of recipients and lead to migration of functional neutrophils into inflamed tissues. A favourable increment of absolute neutrophil counts is observed after concentrates from technically up-to-date apherese from granulocyte-colony stimulating factor-stimulated donors. Most studies indicated a potential positive effect on infection elimination with a minimum cell content of GT (1.5-3 x 10(8)/kg recipient body weight). Although to date the beneficial effect of GT is not proven in prospective randomized trials, in specific situations GT is an option to treat infections along with antibiotics when there is profound neutropenia. However, these patients in critical situations need to be treated within carefully designed studies based on the best known methods for providing granulocyte concentrates in sufficient dose and frequency, standardized similar to other blood product transfusions. That includes definition of minimum cell content, maximum interval between apheresis and application, storage conditions, methods of donor stimulation according to patient's body weight and frequency of GT. This review considers the results of recent studies using GT from cytokine-stimulated donors and the consequences and effects in recipients and donors.

Effects and safety of granulocyte colony-stimulating factor in healthy volunteers

PURPOSE OF REVIEW

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is now widely used in normal donors for collection of peripheral blood progenitor cells for allogeneic transplantation and granulocytes for transfusion. Currently available data on biologic and molecular effects, and safety of rhG-CSF in normal healthy volunteers are reviewed.

RECENT FINDINGS

In addition to its known activating role on neutrophil kinetics and functional status, rhG-CSF administration can affect monocytes, lymphocytes and the hemostatic system. Granulocyte colony-stimulating factor receptors were identified in a variety of nonmyeloid tissues, although their role and functional activity have not always been well defined. Moreover, rhG-CSF is capable of modulating complex cytokine networks and can impact the inflammatory response. In addition to its known mobilizing role for peripheral blood progenitor cells, rhG-CSF can mobilize dendritic and endothelial progenitor cells as well. On a clinical level, serious rhG-CSF-related adverse events are well described (e.g. splenic rupture) but remain rare.

SUMMARY

rhG-CSF effects in healthy volunteers, although normally transient and self-limiting, are now believed to be more complex and heterogeneous than previously thought. Although rhG-CSF administration to healthy volunteers continues to have a favorable risk-benefit profile, these new findings have implications for safeguarding the safety of normal individuals.

Biologic and molecular effects of granulocyte colony-stimulating factor in healthy individuals: recent findings and current challenges

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is widely used in healthy donors for collection of peripheral blood progenitor cells (PBPCs) for allogeneic transplantation and granulocytes for transfusion. The spectrum of its biologic and molecular activities in healthy individuals is coming into sharper focus, creating a unique set of challenges and clarifying the need to monitor and safeguard donor safety. Accumulating evidence indicates that rhG-CSF effects are not limited to the myeloid cell lineage. This may reflect the presence of functional G-CSF receptors on other cell types and tissues, as well as rhG-CSF-induced modulation of cytokine networks. While most rhG-CSF-induced effects are transient and self-limiting, preliminary, provocative data have suggested the possibility of a more durable effect on the chromosomal integrity of lymphocytes. While these reports have not been validated and have been subject to criticism, they are prompting prospective studies and monitoring efforts to determine whether there is a significant risk of long-term adverse events (eg, hematologic malignancies) in healthy PBPC and granulocyte donors. Based on the totality of information that is currently available, the administration of rhG-CSF to healthy donors for the purpose of PBPC donation continues to have a favorable risk-benefit profile.

Mobilizing stem cells from normal donors: is it possible to improve upon G-CSF?

Currently, granulocyte colony stimulating factor (G-CSF) remains the standard mobilizing agent for peripheral blood stem cell (PBSC) donors, allowing the safe collection of adequate PBSCs from the vast majority of donors. However, G-CSF mobilization can be associated with some significant side effects and requires a multi-day dosing regimen. The other cytokine approved for stem cell mobilization, granulocyte-macrophage colony stimulating factor (GM-CSF), alters graft composition and may reduce the development of graft-versus-host disease, but a significant minority of donors fails to provide sufficient CD34+ cells with GM-CSF and some experience unacceptable toxicity. AMD3100 is a promising new mobilizing agent, which may have several advantages over G-CSF for donor mobilization. As it is a direct antagonist of the interaction between the chemokine stromal-derived factor-1 and its receptor CXCR4, AMD3100 mobilizes PBSCs within hours rather than days. It is also well tolerated, with no significant side effects reported in any of the clinical trials to date. Studies of autologous and allogeneic transplantation of AMD3100 mobilized grafts have demonstrated prompt and stable engraftment. Here, we review the current state of stem cell mobilization in normal donors and discuss novel strategies for donor stem cell mobilization.