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PubMed1997

Peripheral blood stem cell mobilization for hematopoietic support of radioimmunotherapy in patients with breast carcinoma.

BACKGROUND: In clinical trials of radiolabeled monoclonal antibodies targeting metastatic breast carcinoma, myelosuppression has been the initial dose-limiting toxicity. We previously have shown that mobilized peripheral blood stem cell transfusions ameliorate this toxicity of radioimmunotherapy (RIT). Because of the difficulty we experienced harvesting adequate numbers of precursor cells from some of these heavily pretreated patients, we have compared the mobilization results and clinical histories of the metastatic breast carcinoma patients referred for RIT with those of metastatic breast carcinoma patients referred for high dose chemotherapy (HDCT) with transplantation. METHODS: Mobilization of stem cells into the peripheral blood was accomplished using granulocyte-colony stimulating factor with or without chemotherapy. Granulocyte macrophage colony-forming assays (CFU-GM) and flow cytometric analysis for CD34 positive cells were used to evaluate the number of hematopoietic precursors mobilized and collected with each apheresis procedure. Clinical characteristics, including prior chemotherapy and external beam radiotherapy, tumor bulk, and performance status, were determined by chart review. RESULTS: Significantly fewer hematopoietic precursors (both CD34 positive cells and CFU-GM) were harvested per procedure from the six RIT patients compared with a group of six patients with metastatic breast carcinoma who had stem cells harvested prior to HDCT (P = 0.002). There was no significant difference between the groups with regard to age or prior radiotherapy. All the RIT patients had received more chemotherapy, had a less favorable performance status (1 vs. 0), and had measurable tumor, whereas all the HDCT patients had minimal residual disease. CONCLUSIONS: Patients enrolled in RIT studies had lower stem cell yields than metastatic breast carcinoma patients scheduled to receive HDCT with stem cell transplantation. Poor mobilization is unlikely to be due to the mobilizing regimen alone and may be related to the intensity of prior therapy and/or tumor bulk. Mobilizing adequate stem cells for multiple treatment cycles from patients on Phase I/II RIT trials may require new, more effective mobilizing regimens, but referral of patients earlier in their disease course, prior to chronic bone marrow damage and disease progression, is recommended strongly.

Adult↗

PubMed2004

Stem cell mobilization in multiple myeloma patients: do we need an age-adjusted regimen for the elderly?

The upper age limit for autologous progenitor cell transplantation in multiple myeloma patients is increasing continuously. We examined whether this shift in the age of pretreated myeloma patients requires modification of mobilization regimen. We compared retrospectively 21 consecutive progenitor cell mobilizations in 15 pts < 60 years (median age 56, range 37-59) with 33 consecutive mobilizations in 23 pts > 60 years (median age 65, range 60-73) of age. The number of CD34 positive circulating cells before scheduled leukapheresis was a mean of 67,935 cells/mL (SEM +/- 17,614) in the younger population and a mean of 19,069 (SEM +/- 5,396) for older pts (P = 0.0027). In patients >60 years, 13/33 mobilizations (including 2 patients with 2 failing attempts) were not successful (39%), compared to 6/21 mobilizations (29%, including 1 patient with 3 failing attempts) in the younger population. The increased number of progenitor cells in the grafts of younger patients led to a more rapid regeneration of leukocytes and platelets after stem cell infusion. Our data show that stem cell mobilization in older multiple myeloma patients is inferior compared to a younger patient population. There is a trend towards more leukapheresis until the target stem cell dose has been collected, and the decreased number of progenitor cells in the actual graft delays engraftment of leukocytes and platelets. The overall number of unsuccessful mobilization attempts, however, did not differ significantly between both age groups. A special "age-adjusted" increase in the dose of growth factors seems unjustified. Improvements in timing of leukapheresis, growth factor application, and mobilizing chemotherapy regimen as well as the use of alternative cytokines should be investigated for both age groups.

Adult↗

PubMed1998

Mobilization of blood stem cells.

Deliberately increasing the number of hematopoietic stem and progenitor cells in the circulation allows faster and more efficient collection of sufficient cells for transplantation in both the allogeneic and autologous settings. These mobilized stem cells, when transplanted, provide quicker hematopoietic recovery for the patient than do nonmobilized blood stem cells or steady-state marrow-derived stem cells. Currently used clinical procedures to produce stem cell mobilization include administration of G-CSF or GM-CSF, either as single agents or in combination with myelosuppressive chemotherapy. Some autologous blood stem cell donors exhibit indifference to currently applied mobilization therapies. This failure to mobilize has been associated with prior stem cell toxic therapy, e.g., radiation therapy and chemotherapy, but the association is incomplete. The observation that occasional normal donors have failed to respond to mobilization therapy indicates that factors other than stem cell damage could also be involved. Recently, a murine model has provided evidence that a circulating factor inhibits mobilization in some settings. Preliminary investigations have suggested that a circulating factor may inhibit mobilization of human hematopoietic progenitor cells in some instances. Studies to identify this factor(s) are underway. The mechanisms of blood stem cell mobilization are still poorly understood and there continues to be the potential to improve this process.

Animals↗

PubMed2000

Mechanisms of stem-/progenitor-cell mobilization: the anti-VLA-4 paradigm.

Since the introduction of mobilized peripheral blood stem cells for transplantation purposes, many studies have been performed using mobilized cells with different mobilization schemes, primarily to optimize mobilization protocols. Studies aiming at mechanisms of mobilization have been few, but have provided useful insights. However, conclusions about mobilization mechanisms were largely inferential. We have attempted to analyze the mobilization process Involving the VLA-4/VCAM-1 pathway. Our findings are summarized and an attempt is made to put our experience into a general model of mobilization.

Animals↗

PubMed1999

Paclitaxel vs cyclophosphamide in peripheral blood stem cell mobilization: comparative studies in a murine model.

Paclitaxel is a promising drug for the treatment of breast and ovarian cancer. It also may play a role in mobilization of peripheral blood stem cells (PBSC), as an alternative to cyclophosphamide (Cy). We investigated the PBSC-mobilizing potential of paclitaxel compared to Cy in a murine model. C57B1/6 mice were primed with intraperitoneal injections of Cy (200 mg/kg) or paclitaxel (60 mg/kg) and were sacrificed 4, 6, 8, or 10 days later. Spleens were harvested and processed to obtain low-density mononuclear cells that were used as PBSC. The number of hematopoietic progenitors (CFU-C) on day 4 was significantly higher in the paclitaxel group when compared to mice receiving Cy (72.0 +/- 1.8 vs 9.8 +/- 2.8, p < 0.001). By day 6, CFU-C became significantly higher in the Cy-treated group compared to the paclitaxel-treated group (195.6 +/- 31.9 vs 95.8 +/- 20.7, p < 0.05) and this trend was maintained. However, the total number of CFU-C recovered per spleen was greater in the paclitaxel-treated group (1.27 x 10(5) +/- 0.53 x 10(5) vs 1.06 x 10(5) +/- 0.36 x 10(5), NS). In contrast to paclitaxel, mobilization with Cy was associated with marked perturbation in the proportion of lymphoid cell subsets in the PBSC population along with functional impairment of lymphocytes. After 24 hours of in vitro IL-2 activation, the cytotoxic effector cell function of the Cy-mobilized PBSC population was lower than that of paclitaxel-mobilized cells when tested against three tumor cell lines (B16, melanoma; C1498, AML; and Yak-1, lymphoma). These results indicate that paclitaxel is an efficient mobilizer of PBSC, leading to early (day 4 to 6) mobilization of PBSC when compared to Cy (day 6 to 8). In addition, paclitaxel was associated with less perturbation of phenotypic and functional characteristics of cells contained within the mobilized PBSC population.

Animals↗

PubMed1990

Rational selective exploitation and distress: employee reactions to performance-based and mobility-based reward allocations.

Prior research has demonstrated that allocators frequently distribute greater rewards to persons with high professional and geographic mobility than to persons with constrained mobility, especially among the very competent. This phenomenon has been termed rational selective exploitation. Do the recipients of such allocations actually experience this distribution rule as unjust and distressing, or is it a misnomer to refer to this phenomenon as exploitation? Two studies were conducted to explore this question. Study 1 was a laboratory experiment in which we manipulated relative performance level, relative mobility level, and allocation standard: performance based versus mobility based. Study 2 was a cross-sectional survey of actual employees in which subjects reported the degree to which performance and mobility were the basis for pay decisions at their places of employment, as well as the degree to which they perceived each standard to be fair. Both studies demonstrated that people regard mobility-based allocations as less fair and more distressing than performance-based allocations. Furthermore, the degree of distress resulting from mobility-based allocations is greater among persons who are disadvantaged by that standard: among people with constrained mobility, especially those who perform at high levels. These findings provide good support for the assertion that so-called rational selective exploitation is indeed distressing to employees. Reactions to this form of distress are also explored, and the implications of these findings for the allocation process are discussed.

Adaptation, Psychological↗

PubMed1998

Combination chemotherapy with mitoguazon, ifosfamide, MTX, etoposide (MIME) and G-CSF can efficiently mobilize PBPC in patients with Hodgkin's and non-Hodgkin's lymphoma.

Many centers use CY and G-CSF to mobilize PBPC. In this study we explored whether a standard chemotherapy regimen consisting of mitoguazon, ifosfamide, MTX and etoposide (MIME) combined with G-CSF was capable of mobilizing PBPC in lymphoma patients. Twelve patients with Hodgkin's disease (HD) and 38 patients with non-Hodgkin's lymphoma (NHL) were mobilized with MIME/G-CSF. Most patients were heavily treated with different chemotherapy regimens receiving a median of 11 cycles (range 3 to 20) of chemotherapy prior to mobilization. It was found that the optimal time of PBPC harvest was at days 12 and 13 after initiating the mobilization regimen. The median number of collected CD34+ cells per kg body weight was 7.1 x 10(6) (range 0.5-26.2). More than 2.0 x 10(6) CD34+ cells/kg were achieved in 69% of the patients after one apheresis. When additional cycles of apheresis were done, only 6% failed to harvest this number of CD34+ cells. There was a statistically significant inverse correlation between the number of prior chemotherapy cycles and CD34+ cell yield (P = 0.003). No such association was found between CD34+ cell yield and prior radiotherapy. When MIME/G-CSF was compared with Dexa-BEAM/G-CSF, it was found that MIME/G-CSF tended to be more efficient in mobilizing PBPC in spite of being less myelotoxic. All patients transplanted with MIME/G-CSF mobilized PBPC had fast and sustained engraftment. These results demonstrate that an ordinary salvage chemotherapy regimen, such as MIME combined with G-CSF can be successfully used to mobilize PBPC.

Adolescent↗

PubMed1998

Marrow repopulating cells in mobilized PBPC can be serially transplanted for up to five generations or be remobilized in PBPC reconstituted mice.

We have evaluated the durability of engraftment and the potential of remobilization in mice reconstituted with mobilized peripheral blood progenitor cells (PBPC). Female mice which had been reconstituted with cytokine-mobilized PBPC from male donors were serially transplanted into second, third, fourth and fifth lethally irradiated female recipients at intervals of 6-10 months. Male-derived hematopoiesis was determined in recipient mice at each serial transplantation. Male-positive CFCs were detected after 5 passages for 45 months, but declined from >95% at passage 1 to 74% at passage 2, 33% at passage 4, and 28% at passage 5. Long-term survival also declined from 97% at passage 2 to 53% at passage 4, and 27% at passage 5. The results demonstrated that mobilized PBPC were able to provide engraftment for more than 45 months, but the engraftment provided by mobilized PBPC decreased at each serial passage. In addition, mice reconstituted with mobilized PBPC (at 1 year post transplantation) were treated with the same cytokines as in the primary mobilization (remobilization). The remobilized PBPC were harvested and transplanted into lethally irradiated secondary recipients. Male-derived CFCs were evaluated at 20 months post transplantation. Mice transplanted with PBPC remobilized with rhG-CSF or rhG-CSF plus rrSCF-PEG showed 70% and 89% male-positive CFCs respectively, demonstrating that mice reconstituted with mobilized PBPC could be remobilized and that the remobilized PBPC were also capable of providing long-term hematopoietic reconstitution. Our studies demonstrated that mobilized PBPC have extensive proliferative or self-renewal capacity to provide durable engraftment and that marrow repopulating cells in PBPC reconstituted mice can be remobilized, suggesting that patients who relapse after PBPC transplantation may be remobilized for a second transplantation to support additional chemotherapy.

Animals↗

PubMed1999

Ifosfamide in combination with paclitaxel or doxorubicin: regimens which effectively mobilize peripheral blood progenitor cells while demonstrating anti-tumor activity in patients with metastatic breast cancer.

For patients with metastatic breast cancer (MBC) who undergo high-dose therapy with autologous peripheral blood progenitor cell (PBPC) transplantation, an important prerequisite is a mobilization regimen that efficiently mobilizes PBPCs while producing an effective anti-tumor effect. We prospectively evaluated ifosfamide-based chemotherapy for mobilization efficiency, toxicity and disease response in 37 patients. Patients received two cycles of the ifosfamide-based regimen; ifosfamide (5 g/m2 with conventional-dose cycle and 6 g/m2 with mobilization cycle) with either 50 mg/m2 doxorubicin (if limited prior anthracycline and/or progression more than 12 months after an anthracycline-based regimen) or 175 mg/m2 paclitaxel. For the mobilization cycle, all patients received additional G-CSF (10 microg/kg SC, daily) commencing 24 h after completion of chemotherapy. The target yield was >6x10(6) CD34+ cells/kg, sufficient to support the subsequent three cycles of high-dose therapy. The mobilization therapy was well tolerated and the peak days for peripheral blood (PB) CD34+ cells were days 10-13 with no significant differences in the PB CD34+ cells mobilization kinetics between the ifosfamide-doxorubicin vs. ifosfamide-paclitaxel regimens. The median PBPC CD34+ cell content ranged from 2.9 to 4.0x10(6)/kg per day during days 9-14. After a median of 3 (range 1-5) collection days, the median total CD34+ cell, CFU-GM and MNC for all 44 individual sets of collections was 9.2x10(6)/kg (range 0.16-54.9), 37x10(4)/kg (range 5.7-247) and 7.3x10(8)/kg (range 2.1-26.1), respectively. The PBPC target yield was achieved in 35 of the 37 patients. The overall response rate for the 31 evaluable patients was 68% with 10% having progressive disease. Thirty-three patients have subsequently received high-dose therapy consisting of three planned cycles of high-dose ifosfamide, thiotepa and paclitaxel with each cycle supported with PBPCs. Rapid neutrophil and platelet recovery has been observed. Ifosfamide with G-CSF in combination with doxorubicin or paclitaxel achieves effective mobilization of PBPC and anti-tumor activity with minimal toxicity.

Adult↗

PubMed1999

Peripheral blood progenitor cell (PBPC) mobilization in heavily pretreated patients with germ cell tumors: a report of 34 cases.

The aim of the study was to evaluate peripheral blood progenitor cell mobilization by disease-specific chemotherapy in heavily pretreated patients with germ cell tumor (GCT), scheduled for high-dose chemotherapy. Thirty-four consecutive patients, 29 males and five females, with advanced GCT referred to our department for high-dose chemotherapy were evaluated retrospectively. Sixteen patients were mobilized by vinblastine 0.11 mg/kg on days 1 and 2, ifosfamide 1200 mg/m2 days 1-5 and cisplatin 20 mg/m2 days 1-5 (VeIP). In 10 patients, etoposide 75 mg/m2 days 1-5 was used instead of vinblastine (VIP), while in eight patients the mobilization was attempted by administering 7 g/m2 of cyclophosphamide. The choice of either etoposide or vinblastine was predicated upon which of these two drugs was associated with best results during premobilization chemotherapy. Cyclophosphamide was selected in patients refractory to previous cisplatin-based salvage chemotherapy. Twenty-five out of 34 patients underwent a successful PBPC collection. In 17 of them one leukapheresis procedure was sufficient to collect the target number of CD34+ cells, while in eight patients a double procedure was necessary. Altogether 33 aphereses were performed in 25 patients. In nine patients leukapheresis was not attempted. This was due to the fact that the chemotherapy failed to mobilize the target number of CD34+ cells in eight of them, treated with the VeIP mobilizing regimen, while one patient treated with high-dose cyclophosphamide rapidly progressed during therapy and for this reason leukapheresis was not undertaken. In conclusion, in heavily pretreated patients with GCT, PBPC mobilization is feasible by a further course of salvage chemotherapy. The choice of either etoposide (VIP) or vinblastine (VeIP) can be predicated upon which of these two drugs was associated with best results during premobilization chemotherapy. In our hands, VeIP seems to be less satisfactory as mobilizing treatment than VIP, possibly due to a superior number of premobilization courses of chemo therapy in some patients. Moreover, high-dose cyclophosphamide remains a good alternative for mobilizing patients refractory to salvage chemotherapy.

Adolescent↗

PubMed1999

Management strategies for the hard-to-mobilize patient.

Delayed hematopoietic engraftment, particularly of platelets, is seen in 5-35% of patients undergoing high-dose chemotherapy with autologous stem cell transplantation. Studies indicate that delayed engraftment is related to low CD34+ cell dose, and that risk factors for poor mobilization of CD34+ cells relate primarily to the type and extent of prior therapy. Data indicating an appropriate strategy to ensure that 'hard-to-mobilize' patients will achieve adequate CD34+ cell numbers are limited. It is clear, however, that marrow harvesting (performed frequently by a number of centers), is of limited value. Remobilization, best accomplished with a regimen of high-dose chemotherapy and cytokines, is of benefit in selected patients, but has substantial costs and morbidity. Instead of ad hoc treatment of patients who have a poor first mobilization, high-risk groups should be identified prospectively, and strategies should be developed to ensure adequate mobilization in all high-risk patients. The first randomized trial utilizing this approach has recently been reported. In this trial, stem cell mobilization with granulocyte colony-stimulating factor (G-CSF) alone was compared to mobilization with G-CSF combined with stem cell factor (SCF) in heavily pretreated patients with Hodgkin's and non-Hodgkin's lymphoma. The combination of G-CSF and SCF led to collection of a higher total CD34+ cell dose compared to G-CSF alone. Further, more patients in the combination group were able to mobilize an optimal CD34+ cell dose (ie 5 x 10(6)/kg). Additional trials are needed to determine long-term outcomes and the economic impact of achieving optimal stem cell mobilization in these patients, who would otherwise not be candidates for high-dose chemotherapy.

Blood Cell Count↗

PubMed2002

GM-CSF-based mobilization effect in normal healthy donors for allogeneic peripheral blood stem cell transplantation.

It is important to optimize methods to mobilize hematopoietic stem cells into peripheral blood (PB) for successful allogeneic peripheral blood stem cell (PBSC) transplantation. Our primary intent was to investigate the role of GM-CSF for mobilization in normal healthy donors and to compare its efficacy in mobilizing stem cells alone, in concurrent combination and in sequential combination with G-CSF in this study. We analyzed the results of the PBSC harvest through large volume leukapheresis from 48 normal healthy donors mobilized by three different regimens including GM-CSF. Donors were assigned sequentially to one of the following regimens for mobilization: GM-CSF 10 microg/kg/day alone (group 1, n = 9); concurrent combination (group 2, n = 20) of G-CSF 5 microg/kg/day and GM-CSF 5 microg/kg/day; sequential combination (group 3, n = 19) of GM-CSF alone 10 microg/kg/day for 3 days followed by G-CSF alone 10 microg/kg/day for 2-3 days. The harvested CD34(+) cell count (P < 0.05) was statistically higher in group 3 than in group 1 or 2. Pre-collection WBC count in donors (P < 0.05), harvested MNC (P < 0.05) and CD3(+) cell count (P < 0.05) of group 2 or 3 were significantly higher than those of group 1. Recipients who received stem cells mobilized with combination regimens showed an earlier recovery of WBC and platelets count than those with GM-CSF alone. The incidence of acute graft-versus-host disease was not statistically different among three recipient groups. GM-CSF-based mobilization was well tolerated in normal healthy donors. The sequential combination regimen appears to be an excellent mobilization strategy and might be preferred as the optimal method in some clinical situations that need a higher number of stem cells.

Adult↗

PubMed1997

Peripheral blood progenitor cell mobilization in patients with primary refractory lymphoma or at first relapse: comparison with patients at diagnosis and impact on clinical outcome.

Peripheral blood progenitor cell (PBPC) mobilization was evaluated in 53 patients receiving the high-dose sequential (HDS) regimen: 27 had non-Hodgkin's lymphoma or Hodgkin's disease, primary refractory or at first relapse, 26 had non-Hodgkin's lymphoma at diagnosis. Mobilization was assessed following either 7 g/m2 cyclophosphamide (48 patients) or 2 g/m2 etoposide, both followed by G-CSF (filgrastim) at 5 microg/kg/d. PBPC mobilization was significantly higher in patients at diagnosis compared to refractory/relapsed patients (median peak values of circulating CFU-GM: 25,209/ml v 4270/ml, P < 0.0001 and CD34+ cells: 286/microl v 47/microl, P < 0.0001). All patients receiving HDS as up-front treatment mobilized enough PBPC for an autograft, often requiring a single leukapheresis; whereas only 15 patients under salvage treatment with HDS were able to complete PBPC autograft. Bone marrow (BM) cells, alone or with PBPC, were needed in six patients, and autograft could not be performed in six patients. Among refractory/relapsed patients, those having a high PBPC mobilization experienced a significantly longer EFS compared to those who had not; autograft completion also significantly enhanced EFS. Thus, the use of an effective mobilizing protocol does not ensure adequate PBPC mobilization in moderately pretreated patients; low mobilization must be considered as an early sign of poor outcome in patients receiving a high-dose salvage programme.

Adult↗

PubMed1999

Peripheral blood progenitor cell (PBPC) counts during steady-state haemopoiesis enable the estimation of the yield of mobilized PBPC after granulocyte colony-stimulating factor supported cytotoxic chemotherapy: an update on 100 patients.

Peripheral blood progenitor cells (PBPC) can be mobilized using chemotherapy and granulocyte colony-stimulating factor (G-CSF). We and others previously reported a correlation of steady-state PBPC counts and the PBPC yield during mobilization in a small group of patients. Here we present data on 100 patients (patients: 25 non-Hodgkin's lymphoma (NHL), five Hodgkin's disease, 35 multiple myeloma (MM), 35 solid tumour) which enabled a detailed analysis of determinants of steady-state PBPC levels and of mobilization efficiency in patient subgroups. Previous irradiation (P = 0.0034) or previous chemotherapy in patients with haematological malignancies (P = 0.0062) led to a depletion of steady-state PB CD34+ cells. A correlation analysis showed steady-state PB CD34+ cells (all patients: r = 0.52, P < 0.0001; NHL patients, r = 0.69, P = 0.0003; MM patients: r = 0.66, P = 0.0001) and PB colony-forming cells can reliably assess the CD34+ cell yield in mobilized PB. In patients with solid tumour a similar trend was observed in mobilization after the first chemotherapy cycle (r = 0.51, P = 0.05) but not if mobilization occurred after the second or further cycle of a sequential dose-intensified G-CSF-supported chemotherapy regimen, when premobilization CD34+ counts were 18-fold elevated (P = 0.004). When the patients with MM (r = 0.63, P = 0.0008) or with NHL (r = 0.65, P = 0.006) were analysed separately, a highly significant correlation of the steady-state PB CD34+ cell count to the mean leukapheresis CD34+ cell yield was found, whereas no correlation was observed for patients with a solid tumour. For patients with haematological malignancies estimates could be calculated which, at a specific steady-state PB CD34+ cell count, could predict with a 95% probability a defined minimum progenitor cell yield. These results enable recognition of patients who mobilize PBPC poorly and may assist selection of patients for novel mobilization regimens.

Adult↗

PubMed2000

Respiratory burst of neutrophils is not required for stem cell mobilization in mice.

It has been suggested that mature neutrophils may play an essential role in the cascade of events leading to egress of stem cells from the bone marrow to the peripheral blood. To investigate further the role of mature neutrophils and of reactive oxygen intermediates (ROIs), known to be involved in the signal transduction of neutrophils, we used mice deficient in respiratory burst, and thus the production of ROIs, to study the involvement of this activation pathway in stem cell mobilization. B6 mice with chronic granulomatous disease (CGD) received either cyclophosphamide (200 mg/kg) on day 1 and granulocyte colony-stimulating factor (G-CSF) (250 microg/kg/d) on days 3-6 or a single dose of interleukin 8 (IL-8; 30 microg/mouse) as a mobilization regimen. On day 7, the number of stem and progenitor cells in blood and bone marrow was compared with control B6 animals (with intact respiratory burst). White blood cell counts, bone marrow cellularity and the frequency of granulocyte-macrophage colony-forming cells (GM-CFC), and cobblestone area-forming cells (CAFC) on days 7 (CAFC-7) and 28 (CAFC-28) were determined. After cyclophosphamide and G-CSF (CY + G), both mouse strains showed considerable mobilization of CAFC-7 and CFU-GM to the blood. Normal mice showed up to a 1905-fold increase in progenitors per ml blood, whereas CGD mice showed up to a 264-fold increase in blood progenitors. IL-8 also induced mobilization in both mouse strains. In addition to progenitors, primitive stem cells measured as CAFC-28 and as CAFC at day 35 were also mobilized by both mobilization protocols in normal as well as in CGD mice. In conclusion, respiratory burst and the subsequent signal transduction pathway do not appear to be required for mobilization of stem cells. Accordingly, neutrophils either are not involved in stem cell mobilization or other signalling pathways within neutrophils must exist that lead to the release of factors which activate stem cell egress from the bone marrow.

Animals↗

PubMed2001

Kinetics of PBPC mobilization by cyclophosphamide, as compared with that by epirubicin/paclitaxel followed by G-CSF support: implications for optimal timing of PBPC harvest.

BACKGROUND: Limited information is available on the mobilization kinetics of autologous PBPCs after induction with various chemotherapy regimens. With PBPC mobilization in patients with breast cancer used as a model for chemotherapy-induced PBPC recruitment, the kinetics of progenitor cells mobilized either with cyclophosphamide (CY) or epirubicin/paclitaxel (EPI-TAX) followed by the administration of G-CSF was compared. STUDY DESIGN AND METHODS: The study included a total of 86 patients with breast cancer (stage II-IV) receiving either CY (n = 39) or EPI-TAX (n = 47), both followed by G-CSF support. The progenitor cell content in peripheral blood and apheresis components was monitored by flow cytometric enumeration of CD34+ cells. PBPC collection was started when the threshold of >20 x 10(6) CD34+ cells per L of peripheral blood was reached. RESULTS: The PBPC collection was begun a median of 9 days after the administration of EPI-TAX followed by G-CSF support, as compared to a median of 13 days after mobilization with CY plus G-CSF. After treatment with CY, the total numbers of PBPCs peaked on Day 1 of apheresis, and they rapidly declined thereafter. In contrast, treatment with EPI-TAX followed by G-CSF administration led to a steady mobilization of CD34+ cells during leukapheresis. The difference in the mobilization patterns with CY and EPI-TAX resulted in a greater yield of CD34+ cells per L of processed blood volume. Compared to EPI-TAX, mobilization with CY required the overall processing of 30 percent less whole-blood volume to reach the target yield of > or = 10 x 10(6) CD34+ cells per kg of body weight. After a median of three apheresis procedures, however, both CY+G-CSF and EPI-TAX+G-CSF were equally effective in obtaining this target yield. CONCLUSION: These results imply that specific PBPC mobilization as part of a given chemotherapy regimen should be taken into consideration before the planning of a PBPC harvest.

Adult↗

PubMed2002

Kinetics of G-CSF-induced granulocyte mobilization in healthy subjects: effects of route of administration and addition of dexamethasone.

BACKGROUND: Granulocyte donors are frequently given G-CSF with or without dexamethasone approximately 18 hours before apheresis to increase cell yields. The purpose of this study was to assess the kinetics of G-CSF plus dexamethasone neutrophil mobilization to determine whether the neutrophils can be mobilized and collected the same day. STUDY DESIGN AND METHODS: Sixteen subjects were given four separate mobilization regimens: IV G-CSF (5 microg/kg), subcutaneous G-CSF (5 microg/kg), IV G-CSF (5 microg/kg) plus oral dexamethasone (8 mg), and subcutaneous G-CSF (5 microg/kg) plus oral dexamethasone (8 mg). Blood cell counts were measured before and after G-CSF administration. RESULTS: Following all four mobilization regimens, neutrophil counts fell 0.5 hour after the mobilizing agents were given, rose above baseline levels at Hour 2, and increased further with each time interval to Hour 8. In the absence of dexamethasone at Hours 2 through 8, there was no difference in neutrophil counts by subcutaneous or IV G-CSF administration routes. The addition of dexamethasone enhanced mobilization of neutrophils from Hours 3 through 24. Through Hour 8, there was no difference in the degree of mobilization among the subcutaneous G-CSF plus dexamethasone and the IV G-CSF plus dexamethasone regimens. However, at Hour 24, neutrophil counts were sustained at higher levels with subcutaneous G-CSF plus dexamethasone than with IV G-CSF plus dexamethasone. CONCLUSIONS: Granulocyte mobilization response to subcutaneous G-CSF plus dexamethasone is sustained at peak levels for 8 to 24 hours after coadministration of the two drugs. There was no advantage to giving G-CSF intravenously.

Administration, Oral↗

PubMed2000

Immunological properties of mononuclear cells from blood stem cell harvests following mobilization with erythropoietin + G-CSF in cancer patients.

BACKGROUND: Although the recombinant granulocyte colony-stimulating factor (G-CSF) is a good CD34 cell mobilizer, the effects of G-CSF mobilization on the immune effector function of the individual is not always optimal. We studied the functional and phenotypic properties of peripheral blood stem cells (PBSC) collected from 15 cancer patients mobilized with G-CSF plus recombinant erythropoietin (EPO). METHODS: The patients received EPO (300 U/kg) and (G-CSF 1 microg/kg) per day as mobilizing cytokines and an autologous graft product was collected with at least daily apheresis procedures until a target number of CD34 cells and mononuclear cells were obtained. Mononuclear cells from the first four PBSC collections were tested for their natural killer (NK), activated NK and lymphokine activated killer (LAK) cytotoxicity in vitro against K562 and Raji tumor target cells. RESULTS: There was a significant increase in NK, activated NK and LAK cytotoxicity in EPO + G-CSF mobilized cells when compared to mononuclear cells from premobilization blood baseline values. Although there was no increase in CD3+ T cells, there was a significant increase in myeloid cells (CD14+), B-cells (CD20+) and NK cells (CD56+) following mobilization. There was no difference in T cell response to the mitogens PHA and Con-A, but there was an increase in B-cell response to PWM following mobilization. Thus, the combination of EPO + G-CSF not only mobilized hematopoietic precursor cells but also increased the number of immune effector cells in the PBSC collections.

Adult↗