G-CSF-mobilized peripheral blood progenitor cells for allogeneic transplantation: safety, kinetics of mobilization, and composition of the graft

Application of peripheral blood stem cells (PBSC) mobilized by recombinant human granulocyte colony stimulating factor for allogeneic PBSC transplantation and the comparison of allogeneic PBSC transplantation and bone marrow transplantation

Recombinant human granulocyte colony stimulating factor (rhG-CSF)-mobilized peripheral blood stem cells (PBSC) are now widely used for allogeneic PBSC transplantation (alloPBSCT). Large numbers of hematopoietic progenitor cells mobilized by rhG-CSF would be considered equivalent or better than bone marrow (BM) cells and would be used as an alternative to BM for allogeneic hematopoietic stem cell transplantation. The complications associated with the administration of rhG-CSF and apheresis in PBSC collection in formal donors are well tolerated and usually acceptable in the short term but some hazardous adverse events such as splenic rupture and cardiac arrest are reported although the incidence is very low. Protective means and stopping rules for safe donation in the collection of PBSC are established. The characteristics of PBSC were clarified; the expression of some adhesion molecules such as CD49d on CD34 positive cells of PBSC have been shown to be low compared to BM stem cells. In alloPBSCT compared with allogeneic BM transplantation (alloBMT), the incidence and frequency of graft versus host disease (GVHD) is of concern because high number of T lymphocytes are infused in alloPBSCT. The incidence and severity of acute GVHD are not increased but chronic GVHD is higher in alloPBSCT compared with alloBMT. The outcome of alloPBSCT and BMT are almost equivalent and conclusive results regarding survival are not yet available.

Peripheral blood progenitor cell transplantation

Peripheral blood progenitor cells (PBPCs) have become increasingly popular over the last 15 years as the source of hematopoietic stem cells for transplantation. In the early 1990s, PBPCs replaced bone marrow (BM) as the preferred source of autologous stem cells, and recently the same phenomenon is seen in the allogeneic setting. Under steady-state conditions, the concentration of PBPCs (as defined by CFU-GM and/or CD34+ cells) is very low, and techniques were developed to increase markedly this concentration. Such mobilization techniques include daily injections of filgrastim (G-CSF) or a combination of chemotherapy and growth factors. Leukapheresis procedures allow the collection of large numbers of circulating white blood cells (and PBPCs). One or two leukapheresis procedures are often sufficient to obtain the minimum number of CD34+ cells considered necessary for prompt and consistent engraftment (i.e., 2.5-5.0 x 10(6)/kg). As compared to BM, autologous transplants with PBPCs lead to faster hematologic recovery and have few, if any, disadvantages. In the allogeneic arena, PBPCs also result in faster engraftment, but at a somewhat higher cost of chronic graft-versus-host disease (GvHD). This may be a double-edged sword leading to both increased graft-versus-tumor effects and increased morbidity. The rapid advances in the study of hematopoietic, and even earlier, stem cells will continue to shape the future of PBPC transplantation.

Mobilization of allogeneic peripheral blood progenitor cells

It is possible to reliably obtain sufficient PBSC from most normal donors to perform allogeneic transplantation. The mobilization regimen, usually administration of a single daily dose of G-CSF at 7.5 to 10 micrograms/kg subcutaneously for 4 to 6 days, is tolerable with acceptable side effects. However, there is wide variability among individuals with respect to the extent of mobilization achieved by the regimen and the optimal timing of apheresis. Studies suggest that the likelihood of obtaining an adequate harvest of CD34+ cells, as defined locally may be enhanced by employing higher doses or different schedules of G-CSF, monitoring the mobilization and/or collection of PBPC, and using apheresis procedures processing 2 or more times blood volume. However, an optimal regimen for mobilization and harvesting for all donors has not yet been identified and a small percentage of donors may not mobilize adequately with G-CSF. Alternative regimens employing combinations of G-CSF and GM-CSF are available that may prove useful in such cases and novel cytokines that are even more effective than G-CSF in mobilizing stem cells are eagerly awaited. Based on currently available experience with normal donors, the short-term safety of G-CSF appears to be acceptable, however there exist several scenarios in which marrow harvesting may be preferable to G-CSF mobilization and apheresis collection of PBPC.

Analysis of factors associated with low peripheral blood progenitor cell collection in normal donors

BACKGROUND

Predictive factors of the response to rHuG-CSF in normal donors have not been extensively studied.

STUDY DESIGN AND METHODS

We analyzed factors influencing CD34+ cell yield in the 1st day of collection in 261 healthy donors from the Spanish National Donor Registry. The median age was 38 years (range, 2-72). The median dose of rHuG-CSF was 10 microg per kg per day (range, 5-20) over 4 days. In 103 donors (40%), <4 x 10(6) per kg CD34+ cells were collected. The variables that were analyzed included age, sex, weight, basal complete blood cell count, dose, type of rHuGCSF and schedule of administration, and maximum WBC count before apheresis.

RESULTS

By univariate analysis, the maximum WBC count (<50 vs. >or=50 x 10(9)/L, p = 0.004), advanced age (p = 0.008), and number of daily rHuG-CSF doses (one vs. two; p = 0.01) correlated with the number of CD34+ cells collected. By multivariate analysis, donors age (<38 vs. >or=38 years; p = 0.014) and a single daily dose of rHuG-CSF (p = 0.005) were the two variables that significantly predicted a low CD34+ cell yield.

CONCLUSION

Donors' age, with a threshold of 38 years or more, and the rHuG-CSF schedule are the factors that significantly affected CD34+ cell mobilization and collection in healthy donors.

Allogeneic transplantation using peripheral blood stem cells

Over the past 9 years there has been a remarkable increase in the use of peripheral blood stem cells (PBSC) for allogeneic transplantation, primarily for matched sibling transplants but also increasingly for unrelated donor transplantation. In 1999 over 50% of all sibling transplants and over 25% of unrelated donor transplants reported to the European Group for Blood and Marrow Transplantation (EBMT) used PBSC. The major reason for this increasing use of PBSC relates to the rapid haemopoietic recovery seen which mirrors the advantages of using PBSC in autologous transplantation. This improvement in engraftment is a consequence of the larger number of stem cells that can be collected from G-CSF-mobilized peripheral blood compared to bone marrow. Evidence from randomized trials now shows a survival advantage for the use of PBSC in patients with advanced leukaemia. The reason for this improved survival appears primarily to relate to a reduced risk of transplant-related mortality and, possibly, a reduced risk of relapse, However, these randomized studies have also confirmed that there is an increased risk of chronic graft-versus-host disease associated with PBSC transplantation and further follow-up is required to determine the long-term impact on outcome.

CD34 cell dose in granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cell grafts affects engraftment kinetics and development of extensive chronic graft-versus-host disease after human leukocyte antigen-identical sibling transplantation

A retrospective analysis of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cell (G-PBMC) products harvested from healthy donors indicates significant variability in both the absolute number and relative proportion of CD34, CD3, and CD14 cells obtained. This report examined whether variations in the cellular composition of G-PBMC products correlated with clinical outcomes after myeloablative allogeneic transplantation. The numbers of CD34, CD3, and CD14 cells infused into 181 human leukocyte antigen (HLA)-identical sibling recipients were analyzed with respect to tempo of engraftment, acute graft-versus-host-disease (GVHD), clinical extensive chronic GVHD, overall survival, and disease relapse. Neither acute GVHD, overall survival, nor disease relapse was statistically significantly associated with CD34, CD3, or CD14 cell doses or the CD14 to CD3 ratio. CD3 and CD14 cell doses and CD14 to CD3 ratios did not correlate with the tempo of neutrophil and platelet engraftment. However, increasing CD34 cell numbers were significantly associated with accelerated neutrophil (P =.03) and platelet (P =.01) engraftment. Higher doses of CD34 cells (> 8.0 x 10(6)/kg) were also associated with a significantly increased hazard of clinical extensive chronic GVHD (HR = 2.3, 95% confidence interval [CI] 1.4-3.7, P =.001), but neither CD3 nor CD14 doses were statistically significantly associated with chronic GVHD. It was concluded that CD34 cell dose in G-PBMC grafts appears to affect both the engraftment kinetics and the development of clinical extensive chronic GVHD in HLA-identical sibling recipients but without a demonstrable impact on survival, relapse, and acute GVHD. Given the morbidity associated with extensive chronic GVHD, efforts to further accelerate engraftment in HLA-matched sibling transplants by increasing CD34 cell number in G-PBMC products may be counterproductive.

Peripheral blood stem cell donation: an analysis from the International Bone Marrow Transplant Registry (IBMTR) and European Group for Blood and Marrow Transplant (EBMT) databases

Donation-related data for 1488 allogeneic peripheral blood stem cell (PBSC) transplants reported to the International Bone Marrow Transplant Registry (IBMTR) or the European Blood and Marrow Transplant Group (EBMT) by 152 teams worldwide between 1994 and 1998 were reviewed. In 1998, 26% of allografts registered with the IBMTR were collected from blood. Median age of PBSC donors was 38 years (range <1-76), and 55% were male. Of 1486 donor-recipient pairs evaluable for HLA compatibility, 1322 (89%) were HLA-identical siblings. Recombinant human granulocyte colony-stimulating factor (G-CSF) was employed to mobilize PBSCs in almost all (99%) cases. One hundred and seventy (20%) of 828 evaluable PBSC donors had a central catheter placed for leukapheresis. Eighty-five percent of 1321 evaluable PBSC grafts were collected with one or two leukaphereses. There were 15 reported donation-related adverse events (1% of evaluable donors). Complications were catheter-related in five. No donation-related fatalities were reported. These data suggest that PBSC donation is becoming more prevalent worldwide. It appears to have a safety profile comparable to marrow harvesting, although experience with the latter is much more extensive.

Allogeneic peripheral blood stem cell transplantation (PBSCT) from HLA-identical sibling donors in children with hematological diseases: a single center pilot study

Between February 1995 and July 1999 25 pediatric patients (8 months to 14 years old) underwent peripheral blood stem cell transplantation (PBSCT) from an HLA-identical sibling donor. Diagnoses included ALL (17), non-ALL (6), and non-malignant disease (2). GVHD prophylaxis consisted of cyclosporine plus methotrexate (15), only cyclosporine (8), cyclosporine plus prednisone (1), or nothing (1). All donors (6 months to 41 years old) received G-CSF at 10 microg/kg/day subcutaneously for 4-5 days and on day 5 underwent large volume leukapheresis. Median number of CD34(+) and CD3(+) cells collected and infused was 6.9 x 10(6) (range 2.5-32.8) and 4.5 x 10(8) (0.5-22.1) per kg of recipient body weight respectively. Median time to achieve ANC >0.5 x 10(9)/l and platelets >20 x 10(9)/l was 10 and 12 days, respectively. Acute GVHD grade > or =II developed in 10 of 24 evaluable patients (42%). Probability of acute GVHD was 62%. Median time to discharge was 25 days (range 14-52). Among 20 evaluable patients, five (25%) developed chronic GVHD at day 100. Probability of chronic GVHD was 29% after 1 year post PBSC. At a median follow-up of 558 (9-2071) days, overall survival for the whole group is 68%. Probabilities of event-free survival, overall survival and relapse for patients with malignant hematological diseases are 53%, 59% and 24% at 5 years, respectively. This study has confirmed the feasibility and safety of mobilization and collection of PBSC products and the applicability of this procedure to the pediatric population, both donors and recipients. Studies including larger numbers of pediatric patients undergoing allogeneic PBSCT are warranted to determine the long-term outcomes of such procedures.

Allogeneic transplantation of CD34+-selected cells from peripheral blood in patients with myeloid malignancies in early phase: a case control comparison with unmodified peripheral blood transplantation

An allogeneic transplantation of CD34(+)-selected cells from peripheral blood (allo-PBT/CD34(+)) from HLA-identical sibling donors was performed in 50 adult patients with acute myeloid leukemia in first complete remission (AML CR1) (n = 29), myelodysplastic syndrome (MDS) (n = 4), or chronic myeloid leukemia in first chronic phase (CML CP1) (n = 17). Clinical results were compared to a concurrent group of 50 patients transplanted with unmodified peripheral blood progenitor cells (allo-PBT), matched for age, diagnosis, and disease stage. The median follow-up period was 29 months (range 1-69). The actuarial probability of developing acute GVHD clinical grade II to IV was 16% (95%CI: 6-26) for the allo-PBT/CD34(+) group and 41% (95%CI: 29-57) for the allo-PBT group (P = 0.002). The actuarial probability of developing extensive chronic GVHD was 22% (95%CI: 8-36) for the allo-PBT/CD34(+) group and 47% (95%CI: 31-63) for the allo-PBT group (P = 0.02). Recipients of allo-PBT/CD34(+) had less toxicity associated with the transplant and better Karnofsky index at the last follow-up. For AML/MDS patients, the actuarial probability of disease-free survival (DFS) for recipients of allo-PBT/CD34(+) and allo-PBT was 65% (95%CI: 45-85) vs43% (95%CI: 28-58) (P = 0.05), respectively. These data provide a rationale for a randomised trial of allo-PBT/CD34(+) vs allo-PBT in AML/MDS patients in early stage of the disease.

Allogeneic haemopoietic cell transplants in Australia, 1996--a multi-centre retrospective comparison of the use of peripheral blood stem cells with bone marrow

A retrospective comparison was carried out on adult patients receiving HLA-identical allogeneic haemopoietic stem cell transplants from siblings in Australia in 1996, comparing bone marrow with G-CSF-mobilised peripheral blood stem cells. A total of 131 transplant recipients from nine centres were included in this study, of whom 79 received bone marrow, 44 blood stem cells and eight both. All but three of the 131 patients had cyclosporin and methotrexate as graft-versus-host disease prophylaxis. The minimum follow-up time for surviving patients is 27 months. Comparisons were carried out between the BM and PBSC groups. There were no significant differences between groups in age, sex, diagnosis, donor characteristics or pretransplant conditioning. Median time to neutrophil recovery of 0.5 x 10(9)/l was 14 days for PBSC recipients, compared to 19 days for marrow recipients (P < 0.0005). median time to platelet recovery of 20 x 10(9)/l was 17 days for PBSC recipients, compared to 28 days for marrow recipients (P < 0.0005). there were no significantly increased risks of either acute or chronic GVHD in the PBSC recipients. there were no significant differences between the groups in the incidence of major transplant-related complications, disease-free survival or overall survival.

Allogeneic peripheral blood stem cell transplantation

Granulocyte colony stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSC) are now widely used instead of bone marrow for autologous transplantation due to earlier hematopoietic recovery after transplant. The low toxicity of G-CSF has prompted phase I and II studies to evaluate PBSC for allogeneic transplantation; these studies have demonstrated that engraftment of neutrophils, red blood cells and platelets is faster with peripheral blood cells compared to marrow. In randomized studies comparing mobilized PBSC and marrow for allogeneic transplantation, most trials have confirmed significantly earlier engraftment with PBSC and similar risks of acute graft-vs.-host disease (GVHD). In some trials, an increase of 10-15% in grade II-IV GVHD has been noted with PBSC. All studies showed a trend towards more chronic GVHD with PBSC. Some randomized studies have shown improved survival and disease-free survival with the use of PBSC due to lowered transplant-related mortality and fewer relapses in recipients of PBSC as a result of improved immune reconstitution and a graft-vs.-leukemia (GVL) effect. This survival benefit is most apparent in patients with more advanced hematologic malignancies, but further studies are needed to define the relative benefits of PBSC for patients with less advanced disease. The GVL effect of PBSC is currently being exploited with the use of non-ablative allografts.

The relative quiescence of hematopoietic stem cells in nonhuman primates

Quiescence has been thought to be required for the retention of the full biological potential of pluripotent hematopoietic stem cells (PHSCs). This hypothesis has been challenged recently by the observation that all murine PHSCs cycle continuously and constantly contribute to steady-state blood cell production. It was asked whether these observations could be extrapolated to describe hematopoiesis in higher mammals. In this series of experiments, the replicative history of PHSCs was examined in baboons by continuously administering bromodeoxyuridine (BrdU) for more than 85 weeks. The results indicate that under steady-state conditions, PHSCs remain largely quiescent but do cycle, albeit at a far lower rate than previously reported for rodent PHSCs. BrdU-labeled cycling PHSCs and progenitor cells were shown to have an extensive proliferative capacity and to contribute to blood cell production for prolonged periods of time. The proportion of PHSCs entering cell cycle could, however, be rapidly increased by the in vivo administration of granulocyte-colony stimulating factor. These data indicate that during steady-state hematopoiesis, baboon PHSCs require prolonged periods of time to cycle and that the proportion of PHSCs in cycle is not fixed but can be altered by external stimuli. The relative quiescence of PHSCs observed in this nonhuman primate model, in contrast to murine PHSCs, might explain the current barriers to genetic modification and ex vivo expansion of human PHSCs.

Safety of granulocyte colony-stimulating factor in normal donors

Granulocyte colony-stimulating factor (G-CSF), which is widely used to mobilize peripheral blood stem cells (PBSC) from normal donors, has led to the use of PBSC as a major alternative to bone marrow for patients undergoing allogeneic transplants. Safety issues related to the administration of G-CSF to normal donors, however, are still under study. The short-term effects after G-CSF administration are well known and manageable. G-CSF induces a hypercoagulable state, which may predispose certain donors to thrombotic complications. A dose of 10 microg/kg/d for 5 days has been recommended for routine clinical use, but the optimal dose and schedule for PBSC collection are still being defined. Small studies to date have shown no late effects of G-CSF administration but there is insufficient information regarding any long-term adverse effects or risks. Although the administration of G-CSF to normal donors for PBSC collection appears safe, longer follow-up is required.

Effect of granulocyte colony-stimulating factor mobilization on phenotypical and functional properties of immune cells

Some phenotypic and functional properties of lymphocytes from bone marrow or peripheral blood stem cell donors were compared in a randomized study. Lymphocyte subsets were analyzed by immunocytometry in blood harvested from bone marrow donors (n = 27) and from peripheral blood stem cell donors before and after granulocyte colony-stimulating factor mobilization (n = 23) and in bone marrow and peripheral blood stem cell grafts. Granulocyte colony-stimulating factor mobilization increased the blood T and B, but not NK, lymphocyte counts. All lymphocyte counts were approximately 10-fold higher in peripheral blood stem cell grafts than in bone marrow grafts. Analysis of CD25, CD95, HLA-DR, and CD45RA expression shows that T-cell activation level was lower after granulocyte colony-stimulating factor mobilization. Similarly, granulocyte colony-stimulating factor reduced by twofold to threefold the percentage of interferon-gamma, interleukin-2, and tumor necrosis factor-alpha-secreting cells within the NK, NK-T, and T-cell subsets and severely impaired the potential for interferon-gamma production at the single-cell level. mRNA levels of both type 1 (interferon-gamma, interleukin-2) and type 2 (interleukin-4, interleukin-13) cytokines were approximately 10-fold lower in peripheral blood stem cell grafts than in bone marrow grafts. This reduced potential of cytokine production was not associated with a preferential mobilization of so-called "suppressive" cells (CD3+CD4-CD8-, CD3+CD8+CD56+, or CD3+TCRVA24+CD161+), nor with a modulation of killer cell receptors CD161, NKB1, and CD94 expression by NK, NK-T, or T cells. Our data demonstrate in a randomized setting that quantitative as well as qualitative differences exist between a bone marrow and a peripheral blood stem cell graft, whose ability to produce type 1 and type 2 cytokines is impaired.

Sequential analysis of CD34+ and CD34- cell subsets in peripheral blood and leukapheresis products from breast cancer patients mobilized with SCF plus G-CSF and cyclophosphamide

Administration of stem cell factor (SCF) has been proven to enhance cytokine-induced mobilization of CD34+ hematopoietic progenitor cells (HPC) into the peripheral blood (PB). The aim of the present study was to explore in a homogeneous group of 22 uniformly treated breast cancer patients: (1) the kinetics of mobilization into PB of both CD34+ and CD34- cell subsets, including dendritic cells, in sequential samples obtained from day +7 up to day +12 after mobilization; and (2) the composition of the CD34+ and CD34- cell subsets present in the two leukapheresis products obtained for each patient. The following CD34+ and CD34- subsets were analyzed: early CD34+ HPC, erythroid-, myeloid- and B-lymphoid-committed CD34+ precursor cells, mature T, B and NK cells, monocytes, neutrophils, eosinophils, basophils, and dendritic cells (DC) including three subsets of lin-/HLADR+DC (CD16+, CD33high and CD123high). Our results show that the absolute number of PB CD34+ HPC progressively increases from day +7 onwards. As far as the CD34- PB leukocyte subsets are concerned, monocytes (CD14+) displayed the earliest recovery after mobilization predicting neutrophil recovery 1 day in advance. The number of CD34+ HPC collected in a single leukapheresis product was always > or = 1.4 x 10(6) cells/kg body weight. No significant changes were observed between the two leukapheresis sessions either as regards their composition in CD34+ HPC subsets or their CD34- leukocyte populations except for a higher ratio of both CD34+ erythroid/CD34+ myeloid HPC (0.35 +/- 0.13 vs 0.30 +/- 0.13; P = 0.04) and neutrophils/monocytes (1.58 +/- 2.1 vs 0.69 +/- 0.27; P = 0.009) found for the first leukapheresis. Interestingly, the overall number of dendritic cells (DC) was higher in the second leukapheresis (1.06 +/- 0.56 vs 1.9 +/- 0.46; P = 0.02) due to a selective increase of the CD16+ antigen-presenting cells. In summary, our results show that the combination of cyclophosphamide, G-CSF and SCF is highly effective for stem cell mobilization, with differences observed in the mobilization kinetics of the different hematopoietic cell subsets analyzed.

Spleen enlargement in healthy donors during G-CSF mobilization of PBPCs

BACKGROUND

Recombinant human G-CSF is widely used to mobilize PBPCs in healthy donors for allogeneic transplantation. There have been concerns about donor safety because of splenic ruptures during G-CSF application. To address this problem, changes in splenic size in 91 healthy donors during G-CSF mobilization of allogeneic PBPCs were investigated.

STUDY DESIGN AND METHODS

For mobilization, G-CSF in a dosage of 7.5 microg per kg per day was administered for 5 days and PBPC collection started Day 5. Splenic size was determined by ultrasound before G-CSF application was started and on the day of the first apheresis.

RESULTS

The mean increase in splenic length was 11 mm (range, 0-28 mm; p<0.0001), whereas a mean increase of 5 mm in width (range, 0-14 mm; p<0.0001) was measured. No major side effects could be observed. There was no significant correlation between the increase in splenic size and the hematologic values, or the age and body-mass index. In a multivariant analysis, no independent risk factor for the development of a spleen enlargement over 19 mm in length and 9 mm in thickness was found in 20 percent of investigated donors.

CONCLUSION

In this prospective trial, a significant spleen enlargement was observed in healthy donors during G-CSF mobilization of allogeneic PBPCs. Further investigations are needed to define the degree of spleen enlargement with higher G-CSF dosages to improve donor safety.

The effect of G-CSF on lymphocyte subsets and CD34+ cells in allogeneic stem cell transplantation

The effect of granulocyte colony-stimulating factor (G-CSF) on peripheral blood lymphocytes (PBL) and CD34+ cell frequency in the apheresis product has been determined in 25 healthy stem cell donors. Peripheral blood mononuclear cells (PBMNC) were collected after five days of G-CSF 10 microg/kg/day s.c., which was well tolerated. The median number of leukocytes increased eight-fold over that of pretreatment levels. Collection of PBMNC lasted a median of two (range, 1-3) days. The mean mononuclear cell (MNC) count and total lymphocyte percentage were 6.69 x 10(8)/kg and 59.08%, respectively, and the frequency of CD34+ cell expression was 2.1% in the apheresis product. The frequency of CD3+, CD4+, CD25+, NK and CD122+ cell expressions in mobilized PBMNC and PBL showed no significant difference. However, the frequency of CD8+, CD8+28+, CD3+DR+, CD19+, CD20+ and CD22+ B cells expression in the apheresis product increased significantly compared to steady-state PBL. In contrast, the frequency of the CD11 a+ and CD8+38+ cell expressions in the apheresis product was decreased compared to the steady-state PBL. The mean yield of CD34+ and CD3+ cells were 13.6 x 10(6) and 2.69 x 10(8)/kg of recipient body weight (RBW), respectively. Following allograft all patients engrafted with >0.5 x 10(9)/l neutrophil and < or = 20 x 10(9)/l platelets on a median of day 13 and 12, respectively. Nine patients had grade II-IV acute GVHD and chronic GVHD occurred in eight patients. Four patients died due to transplant-related complications. There was one late engraftment failure which occurred on the fifth month. Thirteen patients are still alive. In conclusion, these results indicate that administration of G-CSF at 10 microg/kg/day in normal donors alters the lymphocyte subsets and there are significant differences in the lymphocyte contents of the recipients before apheresis and in apheresis product.

CD34+ cell mobilization for allogeneic progenitor cell transplantation: efficacy of a short course of G-CSF

BACKGROUND

G-CSF-mobilized PBPCs are considered the richest source of HPCs for both autologous and allogeneic transplantation, but, despite their wide use, the best dose and schedule for G-CSF administration have not been definitively established.

STUDY DESIGN AND METHODS

With a target of collecting from the peripheral blood > or = 4 x 10(6) CD34+ cells per kg of body weight of the recipient, the short-course administration of glycosylated G-CSF (gly-G-CSF) in 30 healthy donors for an allogeneic transplantation was investigated. Gly-G-CSF was given subcutaneously at a dose of 10 microg per kg per day in two divided doses over 3 days and was followed by a leukapheresis (on the 4th day) 12 hours after the last dose.

RESULTS

A median of 53.5 circulating CD34+ cells per microL (range, 19-190) was found in the 30 donors on the day of first leukapheresis, which allowed a median CD34+ cell collection of 6.0 x 10(6) per kg of body weight of the donor and 6.5 x 10(6) per kg of body weight of the recipient. In 25 (83%) of 30 donors, a single procedure was sufficient to collect the target CD34+ cells, while in the other 5, two leukapheresis procedures were required. Hematologic reconstitution was observed in all patients at a median of 14 days (range, 10-23) for neutrophils and 14.5 days (range, 11-46) for platelets. With a median infusion of 3.9 x 10(8) CD3+ T-lymphocytes per kg of body weight of the recipient (range, 1.3-7.8), acute and chronic GVHD occurred in 13 (43%) of 30 and 15 (60%) of 25 evaluable patients, respectively. After a median follow-up of 337 days from transplant, 22 (73%) of 30 patients are alive in complete remission.

CONCLUSION

A schedule consisting of 3-day administration of gly-G-CSF followed by a single leukapheresis can be proposed and widely accepted by healthy donors, as 84 percent of them reach the target in the estimated time with a reduced drug exposure. The cost of the procedure is reduced, in terms of both the growth factor administration and the number of leukapheresis procedures. The search for the optimum methods of donor management may improve the acceptability of this procedure and increase the number of allogeneic transplantations from PBPCs.

Donor age-related differences in PBPC mobilization with rHuG-CSF

BACKGROUND

Data on the administration of rHuG-CSF to normal donors <18 years old are very limited.

STUDY DESIGN AND METHODS

The results of rHuG-CSF administration to 61 donors <18 years old (Group A) were retrospectively evaluated and compared with results from 353 donors > or = 18 years old (Group B) who are included in the Spanish National Donor Registry. The mean age (range) in Group A and B was 14 (1-17) and 38 (18-71) years, respectively (p<0.001). The mean dose of rHuG-CSF was 10 microg per kg per day (range, 9-16) during a mean of 5 days (range, 4-6). Central venous access was placed more frequently in younger donors (25% vs. 6%; p<0.001).

RESULTS

The mean number of CD34+ cells collected was 7.6 and 6.9 x 10(6) per kg of donor's body weight in Group A and B, respectively. Fifty-six percent of Group A donors needed only one apheresis to achieve > or = 4 x 10(6) CD34+ cells per kg versus 39 percent of Group B donors (p = 0.01). Side effects were more common in Group B (71% vs. 41%; p<0.001).

CONCLUSION

The administration of rHuG-CSF to donors <18 years old leads to CD34+ cell mobilization in a pattern similar to that observed in adults. Greater age was associated with a more frequent requirement for more than one apheresis to achieve a similar number of CD34+ cells.

Allogeneic peripheral blood stem cell transplantation results in less alteration of early T cell compartment homeostasis than bone marrow transplantation

Since low T cell counts evaluated 1 month after allogeneic bone marrow transplantation (BMT) are associated with an increased risk of leukemia relapse (Powles et al., Blood 1998; 91: 3481-3486), we compared, in a randomized multicentric clinical study, the peripheral blood cells obtained 30 days after allogeneic BMT vs allogeneic G-CSF-mobilized peripheral blood stem cell transplantation (BCT) in an HLA-identical setting. T cell counts were higher 30 days after BCT (718+/-142 cells/microl, n = 20) than after BMT (271+/-53 cells/microl, n = 26, P = 0.006). However, T cells were less activated after BCT than after BMT, as demonstrated by a lower expression level of CD25 and a lower percentage of HLA-DR+ and CD95+ T cells. Furthermore, CD4+, CD8+ and CD45RA+ post-BCT T cell counts correlated with the number of cells infused with the PBSC graft, while such a correlation was not observed between post-BMT counts and BM graft cell numbers, suggesting that the intensity of post-transplant peripheral lymphoid expansion and/or deletion differed between BCT and BMT. A comparison of the input of T cells expressing different CD45 isoforms with the post-transplant cell recovery further confirmed that, within the CD4+ T cell subset, post-transplant expansions occurred at a higher level after BMT than after BCT, affecting mainly the CD4+ CD45RO+ subset. Altogether, our data demonstrate for the first time in a randomized setting that homeostasis of the T cell pool is less altered early after BCT than after BMT. This may have a strong impact on the graft-versus-leukemia (GVL) effect and subsequent relapse rate.

The role of cytokines and adhesion molecules for mobilization of peripheral blood stem cells

CD34(+) hematopoietic stem cells from peripheral blood are commonly used for autologous or allogeneic transplantation following high-dose therapy in malignant diseases. The introduction of hematopoietic growth factors such as G-CSF has greatly facilitated the mobilization of CD34(+) cells. The mechanism of stem cell mobilization is not yet clear. It seems to be a multistep process with a crosstalk between cytokines and adhesion molecules. In this review, the role of hematopoietic growth factors, chemokines, and adhesion molecules for mobilization and homing of CD34(+) cells is summarized. In addition, factors influencing the cytokine-induced mobilization in patients and healthy donors are described. The review closes with an overview of new classes of mobilizing drugs such as monoclonal antibodies, specific peptides, or antisense oligonucleotides targeting adhesion molecules.

In vivo expansion of the circulating stem cell pool

Stem cell trafficking between extravascular marrow sites and circulating blood is an essential part of the blood stem cell transplantation technology. Recombinant human G-CSF (rHuG-CSF) is widely used for stem cell peripheralization alone or together with chemopriming mobilizing early and pluripotent CD34+ cell subsets. New cytokine/chemokine mobilization regimens are under investigation such as combined rHuG-CSF and rHu thrombopoietin, rHuG-CSF and interleukin 3, rHuG-CSF and rHu stem cell factor, rHuG-CSF and Flt-3 ligand, human macrophage inflammatory protein, interleukin 1, and interleukin 8. Modifying the adherence of CD34+ cells to extracellular matrix molecules is a new mechanism by which hematopoietic progenitor cells are released into the circulating blood. Blocking the alpha4beta1 integrin receptor on CD34+ progenitor cells by using monoclonal antibodies specific for the heterodimeric complex alpha4beta1 has been shown to further increase the circulating stem cell concentration when given following rHuG-CSF priming. The current clinical research is primarily focused on improving stem cell mobilization efficiency in heavily pretreated and poorly mobilizing patients, and to decrease adverse effects of cytokine treatment.

Unusual adverse events following peripheral blood stem cell (PBSC) mobilisation using granulocyte colony stimulating factor (G-CSF) in healthy donors

Here, we describe two cases of severe pyogenic infection in healthy donors diagnosed immediately following stem cell mobilisation with G-CSF. In the first donor a painful perianal abscess and in the second one an apical abscess required surgical incision. The reported serious adverse events in the literature are reviewed and the potential pathophysiological role of G-CSF or GM-CSF in augmenting inflammatory processes is discussed. In the light of a rapidly increasing number of related and unrelated peripheral blood stem cell donations the need for more comprehensive donor work-up and follow-up for peripheral blood stem cell donors has to be considered. Bone Marrow Transplantation (2000) 26, 811-813.

Matched-pair analysis of peripheral blood stem cells compared to marrow for allogeneic transplantation

We performed a case-control analysis of 42 patients with advanced leukemia or MDS comparing peripheral blood stem cell (PBSC) with marrow grafts (BMT) from HLA-matched sibling donors. PBSC were mobilized with G-CSF (7.5 microg/kg/day) and yielded a median of 6.7 x 10(6) CD34+ cells/kg (range, 1.6-15.0) and 2.7 x 10(8) CD3+ cells/kg (range, 1.1-7.1) vs marrow grafts with a median of 2.0 x 10(8) nucleated cells/kg (range, 1.8-2.2). Recovery was significantly faster after PBSCT compared to BMT, with a median of 17 (range, 12-26) vs 26 (range, 16-36) days, respectively, to neutrophils >0.5 x 10(9)/l (P < 0.01), and 22 (range, 12->60) vs 42 (range, 18->60) days, for platelet recovery (P < 0.01). Transplantation of >/=7 x 10(6) CD34+ cells/kg accelerated recovery to >20 x 10(9) l platelets; median 17 days (range, 12-19) vs 23 days (range, 17-36) for those receiving <7 x 10(6)/kg (P = 0.01). PBSC and marrow recipients had similar risks of grades II-IV or III-IV acute GVHD or extensive chronic GVHD (all P > 0.3). At 1 year after PBSCT and BMT, the risk of relapse was 41% and 32%, respectively (P = 0.47), and the probability of survival was 46% and 48%, respectively (P = 0.70). HLA-matched sibling PBSCT resulted in faster neutrophil and platelet engraftment compared to BMT, with no subsequent differences in acute or chronic GVHD, relapse or survival. A minimum of 7 x 10(6) CD34+ cells/kg in PBSC grafts may be required for very rapid platelet engraftment. Bone Marrow Transplantation (2000) 26, 723-728.

Mobilization kinetics of CD34(+) cells in association with modulation of CD44 and CD31 expression during continuous intravenous administration of G-CSF in normal donors

The aim of the present study is to evaluate the kinetics of CD34(+) cells and investigate the potential modulation of CD44 and CD31 expression on CD34(+) cells during continuous i.v. administration of G-CSF, thus to elucidate the possible mechanism of peripheral blood progenitor cell (PBPC) mobilization. Fifteen healthy donors were enrolled in this study. G-CSF (10 microg/kg/day) was administered for four consecutive days through continuous 24-h i.v. infusion. For measurement of complete blood counts, CD34(+) cell levels and their expression of CD44 and CD31, PB sampling was performed immediately before the administration of G-CSF (steady-state) and after 4, 8, 24, 48, 72, 96, and 120 h of G-CSF administration. The percentage and absolute number of CD34(+) cells significantly increased at day 3 (0. 55 +/- 0.09%, 51.12 +/- 24.83 x 10(3)/ml) and day 4 (0.47 +/- 0.09%, 46.66 +/- 24.93 x 10(3)/ml), compared to the steady-state level (0. 06 +/- 0.09%, 2.03 +/- 5.69 x 10(3)/ml). At day 3 to day 5 following the onset of G-CSF administration, a strong decrease of CD44 and CD31 expression was observed on mobilized CD34(+) cells compared to controls: the relative fluorescence intensity of CD44 and CD31 was, respectively, 50%-70% and 40%-90% lower than that of controls. We conclude that continuous i.v. administration of G-CSF apparently results in more rapid mobilization of CD34(+) cells, and downregulation of CD44 and CD31 on CD34(+) cells is likely to be involved in the mobilization of PBPC after treatment with G-CSF.

Immunobiology of allogeneic peripheral blood mononuclear cells mobilized with granulocyte-colony stimulating factor

The use of mobilized peripheral blood (PB) stem cells for autologous transplantation initially generated much enthusiasm because of enhanced engraftment in comparison to marrow stem cells and avoidance of general anesthesia for the donor. Its application to the allogeneic setting seemed inevitable. For obvious ethical reasons, allogeneic donors are mobilized with cytokines only, mainly granulocyte colony-stimulating factor (G-CSF). Results from preliminary studies suggest that in comparison to standard bone marrow transplants, outcomes such as engraftment, host-versus-graft reaction, graft-versus-host disease, graft-versus-leukemia and immunological reconstitution may be different. Surprisingly, G-CSF, previously recognized as a late acting lineage-specific factor for neutrophil production, not only disrupts homeostasis between stem cells and their microenvironment, but also induces significant quantitative and qualitative changes in the accessory cell compartment, affecting lymphocytes, monocytes, natural killer, dendritic, and stromal cells. Furthermore, mobilization of huge numbers of non-professional antigen presenting cells (CD34+ stem cells) amplifies the tolerizing potential of PB stem cell grafts. Thus, G-CSF mobilization provides PB transplants with different immunobiologic properties in comparison to standard bone marrow grafts. Whether these immunobiologic differences will lead to better transplant outcomes remains to be shown through much awaited results of large randomized clinical trials.

Allogeneic peripheral blood stem cell transplantation for standard risk leukemia: experience of Ibni Sina Hospital

Fifty-three patients with standard risk leukemia who underwent allogeneic peripheral blood stem cell transplantation (alloPBSCT) from their HLA-identical siblings were analyzed for engraftment, incidence and severity of GVHD, and relapse rate. Standard risk leukemia was defined as AML in first complete remission or CML in first chronic phase within the first year after diagnosis. The median age was 34.5 years (range 13-47). Stem cells were mobilized by using 10 microg/kg G-CSF subcutaneously for 5 days. A median of 5. 7 (2.1-21.4) x 106/kg CD34+ cells was collected over a median of 2 (range 1-5) apheresis procedures. Cyclosporin A (CsA) plus short-course MTX were used for GVHD prophylaxis. Recovery to granulocytes >0.5 x 109/l and platelets >20 x 109/l occurred at a median of day +13 (range 8-32) and +13 (range 8-51), respectively. Day +100 transplant-related mortality was 13.2% (7/53). Acute GVHD occurred in 20 of 49 (41%) evaluable patients and only six (12.3%) of them had severe disease (grade III-IV). Chronic GVHD occurred in 30 of 42 (71.4%) evaluable patients. Relapse rate at 2 years was 7. 5%. The median overall and leukemia-free survivals were 22 (4-44) and 20 (3-44) months, respectively. Estimated 4 year leukemia-free and overall survival rates were 60% and 62%, respectively. In conclusion, alloPBSCT in standard risk leukemia seems to be associated with a low relapse rate and no increased risk of acute GVHD, but there is a trend for higher incidence of cGVHD. Bone Marrow Transplantation (2000) 25, 1229-1232.

Immune reconstitution following allogeneic peripheral blood progenitor cell transplantation

Delayed immune reconstitution following allogeneic stem cell transplantation remains a major clinical problem, resulting in significant transplant-related mortality from infectious complications. The recovery of immunity after bone marrow transplantation (BMT) is a complex process dependent on a large number of pre- and post-transplant factors. It has been suggested that the use of peripheral blood instead of bone marrow as stem cell source may accelerate immune reconstitution after allogeneic transplantation. Some authors have recently reported a more rapid recovery of the number and function of T and B cells after allogeneic peripheral blood progenitor cell transplant (allo-PBPCT) in comparison with conventional BMT, results which would reflect the high number of lymphocytes infused to the patients. Such a rapid immune recovery could indeed contribute to the apparent therapeutic advantage of PBPCT when compared with BMT. However, there is limited knowledge on this issue and randomized trials are required to prove whether allo-PBPCT is indeed superior to BMT in terms of immune reconstitution post-transplant. A review of some quantitative and functional aspects of immune recovery after allo-PBPCT is presented in this article.

Single vs twice daily G-CSF dose for peripheral blood stem cells harvest in normal donors and children with non-malignant diseases

The optimal dose and schedule of G-CSF for mobilization of peripheral blood stem cells (PBSC) is not well defined. G-CSF mobilization was performed in a group of healthy donors and paediatric patients for autologous back-up before receiving allogeneic stem cell transplant. Seventeen consecutive subjects who received G-CSF at 5 microg/kg/dose twice daily (group A) were compared with a historical control group of 25 subjects who received a single daily dose of 10 microg/kg/day G-CSF (group B). Double blood volume apheresis for PBSC collection was started on day 5. G-CSF was continued and apheresis repeated until the targeted CD34+ cell dose was achieved. Both groups were comparable for sex, age, body weight and reason for PBSC collection. Over two-thirds of the subjects in both groups were less than 16 years of age. The G-CSF priming and apheresis were well tolerated. When the first day apheresis products were analyzed, group A resulted in significantly higher yield of total nucleated cells (5.91 vs 3.92 x 108/kg, P = 0. 013), mononuclear cells (5.73 vs 3.92 x 108/kg, P = 0.017), CD34+ cells (2.80 vs 1.69 x 106/kg, P = 0.049) and colony-forming units (107 vs 54 x 104/kg, P = 0.010) as compared with group B. We conclude that the two dose schedule is more efficient in mobilizing PBSC in normal donors and children with non-malignant diseases. This approach may reduce the number of aphereses required and thus reduce the transplant cost.

Granulocyte colony-stimulating factor versus granulocyte-macrophage colony-stimulating factor for collection of peripheral blood progenitor cells from healthy donors

The harvesting of peripheral blood progenitor cells (PBPCs) after granulocyte colony-stimulating factor or granulocyte-macrophage colony-stimulating factor stimulation instead of bone marrow in healthy donors has become increasingly popular. Donors, given the choice between bone marrow and PBPC donation, often prefer cytapheresis because of the easier access, no necessity for general anesthesia, and no multiple bone marrow punctures. In addition, accelerated engraftment and immunomodulation by granulocyte colony-stimulating factor-mobilized PBPCs are advantageous for the recipient. However, because of donor inconvenience and poor mobilization, there is a need to develop improved procedures. Aspects such as durability of hematopoietic engraftment, characterization of the earliest stem cell, and composition of PBPCs are not yet well defined, and international donor registration and follow-up must be considered when evaluating long-term safety profiles in healthy donors. This review concentrates on the most significant developments on mobilization of PBPCs published during the past year.

Identification of a genetic locus modulating splenomegaly induced by granulocyte colony-stimulating factor in mice

Clinically detectable splenomegaly and splenic rupture are uncommon but potentially life-threatening consequences of G-CSF administration. Increased spleen size in mice injected with G-CSF is a complex genetic trait amenable to investigation in experimental inter-strain crosses by quantitative trait analysis. A quantitative trait locus (QTL) with highly significant linkage (LOD 7.9) for splenomegaly was identified within a 22 centimorgan (cM) region on chromosome 1. Inheritance of a C57BL/6 haplotype in this region was associated with a greater spleen weight. The relevance of this locus was confirmed by analysing the responses of mice congenic for the distal 12 cM of this region (C57BL/6 and C57BL/6.SJL-Ptprc(a) Pep3(b)). Consistent with the QTL effect, mice lacking C57BL/6 alleles in this region had reduced splenomegaly induced by G-CSF. Intriguingly, peripheral blood neutrophilia and progenitor cell mobilisation responses to G-CSF were also significantly influenced.

The effect of granulocyte colony-stimulating factor administration in healthy donors before bone marrow harvesting

To investigate whether granulocyte colony-stimulating factor (G-CSF) administration to donors before harvest may lighten the burden imposed on them and accelerate the bone marrow (BM) recovery, we administered 2 microgram/kg/d of G-CSF for five consecutive days before the marrow harvest. All of the donors tolerated the G-CSF administration well without severe adverse events. After 5 d of G-CSF treatment, CD34+ cells and granulocyte-macrophage colony-forming units (GM-CFU) in the donors' BM exceeded baseline values by 4.2-fold (range 0.71-316) and 1.6-fold (0.28-118) respectively. The concentration of total nucleated cells (x 107/ml) in the graft increased from 1.61 (0.95-3.23) to 2.44 (1.27-4.01). Although we collected 1020 ml of BM and obtained 1.50 x 1010 nucleated cells from unprimed donors, 940 ml of BM were sufficient to obtain 2.14 x 1010 nucleated cells from primed donors. However, G-CSF-primed BM did not shorten the time to tri-lineage engraftment and the duration of hospitalization compared with unprimed BM, although primed BM contained more CD34+ cells than baseline values. We consider that the advantages of BM priming are not the acceleration of BM recovery but rather the reduction of blood loss during BM harvesting.

Lenograstim-mobilized peripheral blood progenitor cells in volunteer donors: an open label randomized split dose escalating study

Mobilization of peripheral blood cell progenitor cells was investigated in 36 healthy sibling donors using three different split doses of glycosylated rhG-CSF (lenograstim). The donors were randomized into three groups: group 1 was given lenograstim at 8, group 2 at 11 and group 3 at 15 micrograms/kg/day in two split doses, subcutaneously for 4 and 5 days, respectively. Leukapheresis was performed on day 4 or 5 depending on the WBC and CD34+ cell count. We were able to demonstrate that there was a significant correlation between circulating CD34+ cells on the day of harvest and CD34+ cells in the apheresis products in all three groups. The number of CD34+ cells pre-apheresis was inversely correlated with age in group 1 and group 2. However, in group 3, the number of CD34+ cells pre-apheresis did not correlate with age. There was also a difference between the number of progenitor cells mobilized in the three dose groups regarding the time of harvest. Apheresis was performed in groups 1 and 2 on day 5 of mobilization in order to obtain a sufficient number of stem cells for allogeneic transplantation. In contrast, with the split dose of 15 micrograms/kg/day, harvest could be routinely performed on day 4 of stimulation. We conclude that lenograstim given twice a day at doses of 8, 11 and 15 micrograms/kg/day provided different CD34+ cell yields in normal donors, in particular, with regard to the time of harvest. The number of CD34+ cells pre-apheresis was not correlated with age in the group of donors mobilized with a split dose of 15 micrograms/kg/day, indicating that this dosage might also be suitable for older donors.

Comparison of progenitor cell collection on day 4 or day 5 after steady-state stimulation with G-CSF alone in breast cancer patients: influence on CD34+ cell yield, subpopulation, and breast cancer cell contamination

To determine the influence of apheresis timing on CD34+ cell yield, subpopulation, and breast cancer cell contamination, 48 women with breast cancer were stimulated from steady-state hematopoiesis in a prospective but nonrandomized study with 2 x 5 microg/kg G-CSF s.c. alone, and apheresis was started either on day 4 (n = 24) or day 5 (n = 24). Forty-eight women with breast cancer (stage II/III, n = 30; stage IV; n = 12; inflammatory, n = 6) and a median age of 44 years were well balanced between the two groups. In group I, aphersis was started on day 4 and additionally performed on day 5 after G-CSF stimulation, and in group II, apheresis was started on day 5. CD34+ cell count and CD34+ cell subpopulation were determined according to international criteria. Breast cancer cell contamination was detected by immunocytology. The median CD34+ cell harvest on day 4 was 3.3 x 10(6)/kg body weight (range 0.5-12.8) and 6 x 10(6)/kg BW (range 0.3-30) for patients starting on day 5 (p = 0.01). Those patients starting on day 4 achieved a median CD34+ cell count of 4 x 10(6)/kg (range 0.7-13) on day 5 (NS). Twenty-one percent of group I and 71% of group II achieved >5 x 10(6)/kg BW CD34+ cells in the first apheresis, whereas <2.5 x 10(6)/kg BW CD34+ cells in the first apheresis were observed in 38% of group I and 16% of group II. No differences were observed between the CD34+ cell subpopulations, CD34+/CD38+ (10.5% versus 10.5%) and CD34+/Thyl+ (1.5% versus 1.8%). The CD34+ cell harvest from consecutive collecting on days 4 and 5 was nearly identical to the harvest starting on day 5 (6.4 versus 6 x 10(6)/kg). Collecting CD34+ progenitor cells after stimulation with G-CSF alone on day 5 results in a significantly higher cell yield than starting collecting on day 4. No differences in respect to breast cancer cell contamination and CD34+ cell subpopulation were observed.

Recombinant human granulocyte colony-stimulating factor (rHuG-CSF): effects on lymphocyte phenotype and function

Granulocyte colony-stimulating factor (G-CSF) can be administered to healthy donors to mobilize CD34+ peripheral blood progenitor cells (PBPC) for transplantation into HLA-matched allogeneic recipients. Current clinical trials report a similar incidence and severity of acute graft-versus-host disease (G-VHD) compared with transplantation of allogeneic bone marrow (BM) despite the infusion of 1-2 more logs of T lymphocytes. An overview of modulation of T cell function both in animal models and in humans receiving G-CSF is provided. The experimental evidence summarized in the present article highlights a powerful immunoregulatory action exerted by G-CSF, consisting of (1) increase in soluble immunoregulatory cytokines, (2) inhibition of lymphocyte proliferation, and (3) induction of lymphocyte partial activation after mitogenic challenge. These findings offer an experimental background for promising and innovative approaches to cytokine therapy.

Peripheral Blood Stem Cell Transplantation From Unrelated Donors: A Comparison With Marrow Transplantation

Peripheral blood stem cell (PBSC) transplants from HLA-A, -B, and -DR compatible unrelated donors (n = 45) were compared with bone marrow (BM; BM group, n = 45). Eighteen patients received CD34-selected PBSC (CD34 group). The PBSCs contained more mononuclear cells, CD34+, CD3+, and CD56+cells compared with marrow (P < .001). Engraftment was achieved in all 45 patients in the BM group, in 43 of 45 (95%) in the PBSC group, and in 14 of 18 (78%) in the CD34 group (P < .01). In multivariate analysis, a short time to absolute neutrophil count (ANC) equal to 0.5 × 109/L was associated with the PBSC/CD34 groups (P < .001) and granulocyte colony-stimulating factor (G-CSF) treatment (P = .017). A short time to platelets equal to 50 × 109/L was associated with PBSC (P = .003) and no methotrexate (P = .015). Grades II-IV acute graft-versus-host disease (GVHD) was 20% in the BM controls, 30% in the PBSC group, and 18% in the CD34 group (not significant [NS]). The probability of chronic GVHD was 85% in the BM group, 59% in the PBSC group, and 0% in the CD34 group (P < .01). One-year transplant-related mortality was 21% and 27% and survival was 53% and 54% in the BM and PBSC groups, respectively (NS). The 2-year relapse-free survival was 41% and 46% in the two groups, respectively.

The Risk of Residual Molecular and Cytogenetic Disease in Patients With Philadelphia-Chromosome Positive First Chronic Phase Chronic Myelogenous Leukemia Is Reduced After Transplantation of Allogeneic Peripheral Blood Stem Cells Compared With Bone Marrow

The detection of residual molecular and cytogenetic disease was prospectively compared in patients with Philadelphia-chromosome (Ph1) positive first chronic phase chronic myelogenous leukemia (CML) who underwent allogeneic transplantation of unmanipulated peripheral blood stem cells (PBSCT) (n = 29) or bone marrow (BM) (n = 62) using genotypically HLA-identical sibling donors or partially HLA-matched extended family donors. A molecular relapse (MR), as defined by two consecutive positive polymerase chain reaction (PCR) assays for the detection of M-bcr-abl transcripts in a 4-week interval, was found in two of 29 (7%) patients after PBSCT compared with 20 of 62 (32%) patients after bone marrow transplantation (BMT). This corresponds to a 4-year molecular relapse estimate (± standard error) of 7% ± 5% after PBSCT and of 44% ± 8% after BMT (P < .009). With identical follow-up periods of survivors in both patient subsets between 6 and 55 months (median, 28 months), 14 of the 20 patients with MR after BMT progressed to an isolated cytogenetic (n = 10) or a hematologic (n = 4) disease recurrence, resulting in a 4-year cytogenetic relapse estimate of 47% ± 11%, while none of the patients after PBSCT has so far relapsed (P < .006). Multivariate analysis including all potential influencial factors of posttransplant disease recurrence identified the source of stem cells (P < .02) as the only independent predictor of molecular relapse. In conclusion, this prospective comparison of molecular and cytogenetic residual disease demonstrates that peripheral blood stem cell transplants have a more pronounced activity against residual CML cells than bone marrow transplants. Prospective randomized trials comparing PBSCT and BMT in patients with first chronic phase Ph1-positive CML are strictly required to further substantiate differences in the antileukemic activity of the two stem cell sources.

Peripheral Blood Stem Cell Transplantation From Unrelated Donors: A Comparison With Marrow Transplantation

Peripheral blood stem cell (PBSC) transplants from HLA-A, -B, and -DR compatible unrelated donors (n = 45) were compared with bone marrow (BM; BM group, n = 45). Eighteen patients received CD34-selected PBSC (CD34 group). The PBSCs contained more mononuclear cells, CD34+, CD3+, and CD56+cells compared with marrow (P &lt; .001). Engraftment was achieved in all 45 patients in the BM group, in 43 of 45 (95%) in the PBSC group, and in 14 of 18 (78%) in the CD34 group (P &lt; .01). In multivariate analysis, a short time to absolute neutrophil count (ANC) equal to 0.5 × 109/L was associated with the PBSC/CD34 groups (P &lt; .001) and granulocyte colony-stimulating factor (G-CSF) treatment (P = .017). A short time to platelets equal to 50 × 109/L was associated with PBSC (P = .003) and no methotrexate (P = .015). Grades II-IV acute graft-versus-host disease (GVHD) was 20% in the BM controls, 30% in the PBSC group, and 18% in the CD34 group (not significant [NS]). The probability of chronic GVHD was 85% in the BM group, 59% in the PBSC group, and 0% in the CD34 group (P &lt; .01). One-year transplant-related mortality was 21% and 27% and survival was 53% and 54% in the BM and PBSC groups, respectively (NS). The 2-year relapse-free survival was 41% and 46% in the two groups, respectively.

The Risk of Residual Molecular and Cytogenetic Disease in Patients With Philadelphia-Chromosome Positive First Chronic Phase Chronic Myelogenous Leukemia Is Reduced After Transplantation of Allogeneic Peripheral Blood Stem Cells Compared With Bone Marrow

The detection of residual molecular and cytogenetic disease was prospectively compared in patients with Philadelphia-chromosome (Ph1) positive first chronic phase chronic myelogenous leukemia (CML) who underwent allogeneic transplantation of unmanipulated peripheral blood stem cells (PBSCT) (n = 29) or bone marrow (BM) (n = 62) using genotypically HLA-identical sibling donors or partially HLA-matched extended family donors. A molecular relapse (MR), as defined by two consecutive positive polymerase chain reaction (PCR) assays for the detection of M-bcr-abl transcripts in a 4-week interval, was found in two of 29 (7%) patients after PBSCT compared with 20 of 62 (32%) patients after bone marrow transplantation (BMT). This corresponds to a 4-year molecular relapse estimate (± standard error) of 7% ± 5% after PBSCT and of 44% ± 8% after BMT (P &lt; .009). With identical follow-up periods of survivors in both patient subsets between 6 and 55 months (median, 28 months), 14 of the 20 patients with MR after BMT progressed to an isolated cytogenetic (n = 10) or a hematologic (n = 4) disease recurrence, resulting in a 4-year cytogenetic relapse estimate of 47% ± 11%, while none of the patients after PBSCT has so far relapsed (P &lt; .006). Multivariate analysis including all potential influencial factors of posttransplant disease recurrence identified the source of stem cells (P &lt; .02) as the only independent predictor of molecular relapse. In conclusion, this prospective comparison of molecular and cytogenetic residual disease demonstrates that peripheral blood stem cell transplants have a more pronounced activity against residual CML cells than bone marrow transplants. Prospective randomized trials comparing PBSCT and BMT in patients with first chronic phase Ph1-positive CML are strictly required to further substantiate differences in the antileukemic activity of the two stem cell sources.

High-versus standard-dose filgrastim (rhG-CSF) for mobilization of peripheral-blood progenitor cells from allogeneic donors and CD34(+) immunoselection

PURPOSE

The efficacy of a high- versus a standard-dose filgrastim (recombinant human granulocyte colony-stimulating factor, or rhG-CSF) regimen to mobilize peripheral-blood progenitor cells (PBPCs) for allogeneic transplantation was investigated in 75 healthy donors.

PATIENTS AND METHODS

From December 1994 to December 1997, 75 consecutive donors (median age, 38 years; range, 17 to 67 years) were assigned to two different schedules of rhG-CSF for PBPC mobilization. Fifty donors received 24 microg rhG-CSF/kg body weight (BW) divided into two daily subcutaneous injections (two doses of 12 microg, group A), whereas 25 were treated with 10 microg rhG-CSF once daily (group B). Apheresis was started on day 4 in group A and on day 5 in group B. Target CD34(+) cell numbers in apheresis products were >/= 4 x 10(6)/kg recipient BW.

RESULTS

Cytokine priming and collection of PBPCs were equally well tolerated in both groups. Significantly higher CD34(+) cell numbers in group A with 3. 7 x 10(6)/kg recipient BW/apheresis (0.47 x 10(6)/L apheresis) compared with 2 x 10(6)/kg recipient BW/apheresis (0.25 x 10(6)/L apharesis) in group B were obtained (P <.05). Using standard aphereses (median, 9 L), two doses of 12 microg rhG-CSF/kg allowed collection of >/= 4 x 10(6)/kg CD34(+) cells with two aphereses (range, one to three) in group A versus three aphereses (range, one to six) in group B (P <.015). Donor age, sex, and BW influenced the collection of CD34(+) cell numbers: in particular, significantly higher apheresis results were obtained in donors younger than 40 years compared with donors older than 40 years of age (P <.05). In 65 CD34(+) selection procedures using avidin-biotin immunoabsorption columns (Ceprate SC System, CellPro, Bothell, WA), a median CD34(+) purity of 53%, CD34(+) recovery of 40%, and the collection of 2 x 10(6)/kg CD34(+) cells/selection were achieved. In group A with higher CD34(+) cells/kg/apheresis, CD34(+) purity, recovery, and cell yields were 60%, 45%, and 2.3 x 10(6)/kg/selection, respectively, as compared with 48%, 31%, and 0.7 x 10(6)/kg in group B (P <.05).

CONCLUSION

Our results demonstrate that twice daily rhG-CSF (two doses of 12 microg/kg BM) compared with once daily rhG-CSF (10 microg/kg BW), in addition to being well tolerated, significantly improves PBPC mobilization, allows the collection of higher numbers of CD34(+) cells with one or two standard aphereses, and facilitates subsequent selection procedures in healthy allogeneic donors.

Allogeneic blood progenitor cell collection in normal donors after mobilization with filgrastim: the M.D. Anderson Cancer Center experience

BACKGROUND

Information on the safety and efficacy of allogeneic peripheral blood progenitor cell (PBPC) collection in filgrastim-mobilized normal donors is still limited.

STUDY DESIGN AND METHODS

The PBPC donor database from a 42-month period (12/94-5/98) was reviewed for apheresis and clinical data related to PBPC donation. Normal PBPC donors received filgrastim (6 microg/kg subcutaneously every 12 hours) for 3 to 4 days and subsequently underwent daily leukapheresis. The target collection was > or =4 x 10(6)CD34+ cells per kg of recipient's body weight.

RESULTS

A total of 350 donors were found to be evaluable. Their median age was 41 years (range, 4-79). Their median preapheresis white cell count was 42.8 x 10(9) per L (range, 18.3-91.6). Of these donors, 17 (5%) had inadequate peripheral venous access. Leukapheresis could not be completed because of apheresis-related adverse events in 2 donors (0.5%). Of the 324 donors evaluable for apheresis yield data, 221 (68%) reached the collection target with one leukapheresis. The median CD34+ cell dose collected (first leukapheresis) was 462 x 10(6) (range, 29-1463). The main adverse events related to filgrastim administration in donors evaluable for toxicity (n = 341) were bone pain (84%), headache (54%), fatigue (31%), and nausea (13%). These events were rated as moderate to severe (grade 2-3) by 171 (50%) of the donors. In 2 donors (0.5%), they prompted the discontinuation of filgrastim administration.

CONCLUSION

PBPC apheresis for allogeneic transplantation is safe and well tolerated. It allows the collection of an "acceptable" PBPC dose in most normal donors with one leukapheresis, with minimal need for invasive procedures.

Peripheral blood stem cell mobilization for high-dose chemotherapy

Several studies have clearly documented a more rapid hematopoietic recovery with growth factor-mobilized PBSC than with bone marrow. Time to engraftment for neutrophils and platelets average 8-12 days in contrast to 2-4 weeks after bone marrow. This rapid hematopoietic recovery with PBSC has decreased the duration of hospitalization, transfusion requirements, and costs. Although growth factors alone may mobilize enough PBSC for high-dose chemotherapy, administration of growth factor after submyeloablative chemotherapy increases the yield of CD34+ cells. Based on the current data, CD34+ cell content of PBSC appears to be the single most powerful predictor of hematopoietic recovery. Infusion of > or =5 x 10(6) CD34+ cells/kg is associated with a rapid engraftment of neutrophils and platelets, although successful engraftment has also been reported with infusion of 2.5-5 x 10(6) CD34+ cells/kg. Age, prior radiotherapy, marrow involvement, and prior chemotherapy regimens are important factors influencing the yield of stem cells. Therefore, using these pa-rameters, we may identify the patients who will fail to mobilize sufficient numbers of PBSC before collection and use new strategies for stem cell mobilization. Because of the ease of collection and rapid engraftment after myeloablative therapy, PBSC have replaced bone marrow for autologous transplantation and may supplant bone marrow for allogeneic transplantation in the near future.

Granulocyte colony-stimulating factor-mobilized peripheral blood stem cells in beta-thalassemia patients: kinetics of mobilization and composition of apheresis product

beta-Thalassemias are often associated with bone marrow expansion and immunomodulation in terms of lymphocyte subsets and cytokine levels in the peripheral blood. The mobilization of peripheral blood stem cells (PBSC) by cytokines in such a background has not been reported. If achieved, the apheresis product could be used as a stem cell back-up for beta-thalassemia patients prior to bone marrow transplant. PBSC collection may also become a means for providing stem and progenitor cells for gene manipulation and therapy of this disorder. The aim of the study was to assess the administration of G-CSF in mobilizing stem and progenitor cells in these patients and to compare the kinetics of CD34+ cells and lymphocyte subsets with those of healthy PBSC donors. Results showed that the CD34+ cells were effectively mobilized by G-CSF (10-16 micrograms/day per kg) in 20 thalassemia patients and 11 healthy donors. Although no significant difference was observed in levels of daily stem cell counts between the two groups of subjects, a 1 day delay in achieving peak levels of CD34+ cells was observed in the majority of thalassemia patients. The peak increase of CD34+ cells was 21.5 +/- 6.1-fold and 30.8 +/- 7.6-fold of the basal steady-state levels in thalassemia patients and healthy donors, respectively. Similar to the situation of healthy donors, G-CSF stimulated essentially the CD34+ cells and the myeloid lineage (granulocytes, monocytes) in thalassemia patients and had a slight effect on lymphocyte subsets (T-helper, T-suppressor, NK, and B cells) and activation (CD25, HLA-DR, and CD45RO). Compositions of the apheresis products, including CD34+CD38-, CD34+CD33+ and CD34+HLA-DR- cells, were similar in the two groups of subjects. Correlation studies showed that the level of CD34+ cells in the PB is a good indicator of that in the apheresis product (r = 0.88, p < 0.001). The study has demonstrated that under close monitoring of CD34+ cell levels in PB, the mobilization by G-CSF and collection of PBSC in beta-thalassemia patients are feasible.

Seasonal variation in the incidence of Hodgkin's disease

Earlier literature suggested there may be a seasonal rhythm of onset of Hodgkin's disease. This issue has been re-examined using population-based prospectively-collected data with high ascertainment levels. The Data Collection Study (DCS) of the Leukaemia Research Fund (LRF) Centre for Clinical Epidemiology (University of Leeds) generated the information used, which was based on a population of 13.5 million--about one quarter of England and Wales--over 10 years. The RYE histopathological classification was employed. The findings show that in patients with nodular sclerosing histopathology there was a highly significant circannual rhythm with a low amplitude (extent of seasonal variation) and a peak in March. A significant, but different, rhythm with a high amplitude and a peak in August was found in lymphocyte predominant Hodgkin's disease. However, this finding is less certain, due to smaller numbers and a lower significance level. The main conclusion is that there is a highly significant seasonality in nodular sclerosing Hodgkin's disease. The findings provide further evidence that nodular sclerosing and lymphocyte predominant may be two different diseases. The differing seasonality rhythms may provide aetiological clues.

Allogeneic peripheral blood stem cell transplantation in acute non-lymphoblastic leukemia

Unmodified allogeneic peripheral blood stem cell transplantation (alloPBSCT) was performed in 20 consecutive acute non-lymphoblastic leukemia (ANLL) patients from their HLA-identical siblings. There were 11 males and 9 females. Median age was 34 years (range 17-43). Donors were primed with 2.5-15 micrograms/kg/day s.c. granulocyte-colony stimulating factor (G-CSF, Neupogen, Roche). Conditioning regimen was Bu (16 mg/kg) + Cy (120 mg/kg) in 19 patients and high dose Ara-C (3 gr/m2 twice daily for 3 days) for one patient who relapsed after bone marrow transplantation. Eighteen patients were in CR1. CsA + short-term MTX (n = 19) or CsA alone (n = 1) were used for graft versus host disease (GVHD) prophylaxis. The median number of apheresis procedures for each patient was 2 (2-4). A median of 6.5 (3.2-38.2) x 10(8)/kg MNC or 9.4 (2.2-12.4) x 10(6)/kg CD34+ cells were given. Median days to reach granulocyte of > 0.5 x 10(9)/l and platelet of > 50 x 10(9)/l were 12 (10-14) and 15 (11-35) respectively. Day 100 transplant-related mortality was 20 per cent (4/20). Grade 2 to 4 AGVHD was seen in 8 out of 17 (47%) evaluable patients. Severe AGVHD occurred in 3 out of 17 (18%). Clinical CGVHD of all grades developed in 12 out of 17 (70%) evaluable patients. The mean disease-free survival and overall survival were 17 (range: 8-33 months) and 18 months (range: 10-34 months), respectively. In conclusion, alloPBSCT in ANLL is associated with a faster engraftment, no greater incidence of AGVHD, but increased risk of CGVHD.