Factors influencing collection and engraftment of CD34+ cells in patients with breast cancer following high-dose chemotherapy and autologous peripheral blood progenitor cell transplantation

Although autologous PBPC transplantation is being used increasingly for the treatment of breast cancer, there are few data on factors influencing mobilization and engraftment in these patients. We have analyzed these factors in 70 patients with advanced or metastatic breast cancer undergoing autologous PBPC transplantation. All patients were mobilized after stimulation with G-CSF, and a median of 3.16 x 10(6)/kg CD34+ cells (range 0.75-23.33) were infused. All patients received conditioning with a combination of cyclophosphamide, thiotepa, and carboplatin, and postinfusion G-CSF was administered to 60 patients. The median times to reach 0.5 x 10(9)/L and 1 x 10(9)/L neutrophils were 10 and 11 days, respectively. The median times to obtain 20 x 10(9)/L and 50 x 10(9)/L platelets were 12 and 18 days, respectively. An analysis of factors that influence CD34+ cell collection was performed by linear regression. Previous radiation therapy and increasing age were associated with lower numbers of CD34+ cells collected. Those variables that could influence the tempo of engraftment were examined by multivariate analysis using Cox regression models. The number of CD34+ cells infused was found to influence both neutrophil and platelet recovery. The use of G-CSF after transplant, accelerated neutrophil recovery, and having more than six cycles of previous chemotherapy was an unfavorable factor for recovering >50 x 10(9)/L platelets.     

High platelet contamination in progenitor cell concentrates results in significantly lower CD34+ yield after immunoselection

BACKGROUND: Selection of CD34+ cells by specific immunoselection leads to a significant loss of those cells. The factors influencing the yield and purity are not well identified. The results of CD34+ selection from peripheral blood progenitor cells (PBPCs) with high and low platelet contamination that are harvested with two different cell separators are reported. STUDY DESIGN AND METHODS: A progenitor cell concentrator (Ceprate SC, CellPro) was used to select CD34+ cells from 41 PBPC concentrates from 23 consecutive patients with relapsed non-Hodgkin's lymphoma (n = 3), breast cancer (n = 17), and multiple myeloma (n = 3). PBPC collection was performed by using two cell separators (CS3000 Plus, Fenwal: Group A, n = 11; and Spectra, COBE: Group B, n = 9). To reduce platelet contamination in the Spectra PBPC concentrates, an additional low-speed centrifugation was performed before CD34+ cell selection (Group C, n = 3). Leukapheresis components were stored overnight at 4 degrees C and combined with the next day's collection before the CD34+ selection procedure in 19 patients. RESULTS: A median of 1.5 leukapheresis procedures per patient were performed. Pooled PBPC concentrates showed no statistical difference in median numbers of white cells and CD34+ cells in Groups A and B: 3.2 (0.8-9.2) versus 4.4 (1.6-8. 3) x 10(10) white cells per kg and 15.0 (4.7-24.0) versus 12.0 (5. 6-34.0) x 10(6) CD34+ cells per kg. Platelet contamination was significantly higher in Group B: 0.67 (0.15-2.4) versus 2.3 (0.5-7. 1) x 10(11) (p = 0.0273). After the selection process, there was a significantly greater loss of CD34+ cells in Group B than in Group A: 39.1 versus 63.2 percent (p = 0.0070), with a median purity of 78. 0 percent versus 81.0 percent. An additional low-speed centrifugation before CD34+ cell selection seemed to reduce CD34+ cell loss in Group C with 16.9, 31.9, and 37.5 percent, respectively. CONCLUSION: CD34+ cell selection from PBPC concentrates resulted in an increased loss of CD34+ cells in concentrates with a higher platelet content. To improve CD34+ yield, PBPC concentrates with an initially low platelet contamination should be used, or additional low-speed centrifugation should be performed.     

The number of CD34+ cells mobilized into the peripheral blood can predict the quality of subsequent collections

PBPC were mobilized using a variety of chemotherapy regimens plus G-CSF in a group of 126 consecutive patients. Data are presented that show a close correlation between the number of CD34+ cells mobilized into the peripheral blood (PB) and the number of CD34+ cells subsequently collected by leukapheresis (R = 0.904). On the basis of this correlation, a regression formula was calculated that could give an estimate of the total number of CD34+ cells likely to be collected by leukapheresis from a given number of CD34+ cells per microliter PB. An easy-to-read table has been compiled to show how this type of analysis can be applied to predict the likely dose of CD34+ cells that will be obtained by leukapheresis over a wide range of patient weights.     

The role of diagnosis in patients failing peripheral blood progenitor cell mobilization

BACKGROUND: Failure to mobilize PBPCs for auto-logous transplantation has mostly been attributed to previous therapy and poses therapeutic problems. STUDY DESIGN AND METHODS: The role of underlying disease was analyzed in 17 of 73 (23%) patients with PBPC mobilization failure, and secondary mobilization with high-dose filgrastim was attempted. RESULTS: Of 16 patients with acute leukemia, 13 (81%) mobilized poorly. In contrast, of 57 patients with non-Hodgkin's lymphoma, Hodgkin's lymphoma, multiple myeloma, and solid tumor, 53 (93%, p < 0.001) showed good PBPC mobilization. Relapsed disease did not predispose to poor mobilization. As secondary mobilization attempt, 7 patients received 25 micro g per kg per day filgrastim without chemotherapy leading to a 3.7 +/- 2.8-fold (SD) increase in the maximum number of circulating CD34+ cells (p = 0.104). PBPC apheresis yielded 3.3 (+/-0.5) x 10(6) CD34+ cells per kg of body weight in 5 patients. Four poor mobilizers received 50 micro g per kg per day filgrastim as second or third mobilization attempt. Circulating CD34+ cells in these patients increased by 1.5 (+/-0.7) compared with the primary G-CSF application. CONCLUSION: Selective PBPC mobilization failure was seen in patients with acute leukemia whereas remarkably good mobilization was seen in other malignancies. Increasing the filgrastim dose to 25 micro g per kg per day may allow PBPC collection in patients failing PBPC mobilization.     

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.     

Combined isolation of CD34+ progenitor cells and reduction of B cells from peripheral blood by use of immunomagnetic methods

BACKGROUND: Malignant cells may contribute to relapse after autologous hematopoietic cell transplantation The effectiveness of a double immunomagnetic purging strategy combining CD34-positive with B-negative cell selection to purge peripheral blood progenitor cells (PBPCs) from patients with chronic lymphoproliferative disorders has been analyzed. STUDY DESIGN AND METHODS: Twenty-two CD34+ cell selections from patients with follicular lymphoma (n = 14), chronic lymphocytic leukemia (n = 6), mantle cell lymphoma (n = 1), and splenic marginal zone lymphoma (n = 1) were performed by use of a magnetic cell selector followed by a negative cell selection step with anti-CD19 monoclonal antibody bound to immunomagnetic beads. RESULTS: The PBPC components contained median CD34+ cells of 1.24 percent (range, 0.38-3.92%) and CD19+ cells of 1.83 percent (range, 0.06-69.7%). After positive selection (n = 22), 49 percent (range, 16-72%) of CD34+ cells were recovered with a purity of 93 percent (range, 24-99%). The double-positive and -negative selections (n = 20) yielded 57.5 percent of CD34+ cells (range, 33.4-79.4%) with a purity of 95 percent (range, 63-99%). Logarithms of B-cell reduction in the CD34+-cell-enriched B-cell-depleted component had a median value of 3.63 (range, 2.74-4.84 log) and CD19+ and CD5+ cells for chronic lymphocytic leukemia patients with more than 4.56 log (>3.6-5.6 log). Of 13 PBPC components that had a tumor-specific clonal signal, 10 became PCR negative after the double-selection procedure. CONCLUSION: Combined positive and negative magnetic cell selection achieves a high grade of tumor cell reduction with up to 77 percent of the grafts being negative for tumor-specific clonal signal by PCR analysis. This technique preserves an adequate recovery of progenitor cells able to engraft.     

Mobilization kinetics of CD34+/Thy-1dim progenitor cells during recombinant human granulocyte-colony-stimulating factor administration in normal donors

BACKGROUND: Allogeneic transplantation of granulocyte-colony- stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPCs) from normal related donors is effective in achieving engraftment with a relatively short period of posttransplantation aplasia. The optimal dose and composition of PBPC transplants are unknown. The CD34+/Thy-1dim progenitor cell subset is enriched for putative stem cells. STUDY DESIGN AND METHODS: The kinetics of the primitive subpopulation were prospectively studied in nine normal donors receiving recombinant human G-CSF (6 microg/kg) subcutaneously twice daily for 6 days for collection of PBPCs for allogeneic transplantation. RESULTS: The concentration (mean +/− SD) of the circulating CD34+/Thy-1dim subset increased from a baseline of 0.9 +/− 0.9 × 10(3) to 29.2 +/− 22.1 × 10(3) per mL on Day 4 and 38.0 +/− 29.8 × 10(3) per mL on Day 6. The level of CD34+/Thy-1dim cells was closely correlated with the overall level of CD34+ cells. At baseline, CD34+/Thy-1dim cells composed 21.1 percent of the total CD34+ cells, increasing to 36.3 percent at the peak of mobilization. CONCLUSION: CD34+/Thy-1dim cells are optimally mobilized on Days 4 to 6 of recombinant human G-CSF treatment.     

The number of CD34(+) cells in peripheral blood as a predictor of the CD34(+) yield in patients going to autologous stem cell transplantation

The number of CD34(+) cells in peripheral blood (PB) is a guide to the optimal timing to harvest peripheral blood progenitor cells (PBPC). The objective was to determine the number of CD34(+) cells in PB that allows achieving a final apheresis product containing > or =1.5 x 10(6) CD34(+) cells/kg, performing up to three aphereses. Between March 1999 and August 2003, patients with hematological and solid malignancies who underwent leukapheresis for autologous bone marrow transplantation were prospectively evaluated. Seventy-two aphereses in 48 patients were performed (mean 1.45 per patient; range 1-3). PBPC were mobilized with cyclophosphamide plus recombinant human granulocyte-colony stimulating factor (G-CSF) (n = 40), other chemotherapy drugs plus G-CSF (n = 7), or G-CSF alone (n = 1). We found a strong correlation between the CD34(+) cells count in peripheral blood and the CD34(+) cells yielded (r = 0.903; P < 0.0001). Using receiver-operating characteristic (ROC) curves, the minimum number of CD34(+) cells in PB to obtain > or =1.5 x 10(6)/kg in the first apheresis was 16.48 cells/microL (sensitivity 100%; specificity 95%). The best cut-off point necessary to obtain the same target in the final harvest was 15.48 cells/microL, performing up to three aphereses (sensitivity 89%; specificity 100%). In our experience, > or =15 CD34(+) cells/microL is the best predictor to begin the apheresis procedure. Based on this threshold level, it is possible to achieve at least 1.5 x 10(6)/kg CD34(+) cells in the graft with < or =3 collections.     

Combined CD34 positive plus CD2 negative selection for effective T-cell depletion as GvHD-prophylaxis in HLA-nonidentical blood progenitor cell transplantation

G-CSF mobilized, T-cell-depleted peripheral blood progenitor cells (PBPC) and T-cell-depleted bone marrow (BM) were given to seven children (6 AL, 1 SCID) to prevent severe graft-versus-host-disease (GvHD) as well as graft rejection after transplantation from HLA-nonidentical parental donors. BM was T-cell-depleted by lectin agglutination and E-rosetting. For T-cell-depletion of the PBPC grafts a combination of CD34+ selection with the Ceprate SC immunoadsorption system and a subsequent depletion of CD2+ cells with immunomagnetic Dynabeads was used. The overall recovery was 0.3 (0.1-1.2)% for nucleated cells, 29 (18-45)% for CD3+ cells, respectively. The purity of CD34+ cells was 87 (68-97)% with a 0.3(0.05-0.7)% residual CD3+ T-cell contamination. In spite of the large T-cell number in the PBPC grafts the combination of CD34 positive and subsequent CD2 negative selection achieved a more than 4 log T-cell depletion and prevents severe GvHD even in HLA-nonidentical transplantation. In addition, if a high dose of progenitor cells ensures stable engraftment, this new approach could increase the possibility of wider use of HLA-mismatched family donors for transplantation.     

Successful mobilization of peripheral blood HPCs with G-CSF alone in patients failing to achieve sufficient numbers of CD34+ cells and/or CFU-GM with chemotherapy and G-CSF

BACKGROUND: Mobilization with chemotherapy and G-CSF may result in poor peripheral blood HPC collection, yielding <2 x 10(6) CD34+ cells per kg or <10 x 10(4) CFU-GM per kg in leukapheresis procedures. The best mobilization strategy for oncology patients remains unclear. STUDY DESIGN AND METHODS: In 27 patients who met either the CD34 (n = 3) or CFU-GM (n = 2) criteria or both (n = 22), the results obtained with two successive strategies-that is, chemotherapy and G-CSF at 10 microg per kg (Group 1, n = 7) and G-CSF at 10 microg per kg alone (Group 2, n = 20) used for a second mobilization course-were retrospectively analyzed. The patients had non-Hodgkin's lymphoma (5), Hodgkin's disease (3), multiple myeloma (5), chronic myeloid leukemia (1), acute myeloid leukemia (1), breast cancer (6), or other solid tumors (6). Previous therapy consisted of 10 (1-31) cycles of chemotherapy with additional chlorambucil (n = 3), interferon (n = 3), and radiotherapy (n = 7). RESULTS: The second collection was undertaken a median of 35 days after the first one. In Group 1, the results of the two mobilizations were identical. In Group 2, the number of CD34+ cells per kg per apheresis (0.17 [0.02-0.45] vs. 0.44 [0.11-0.45], p = 0. 00002), as well as the number of CFU-GM (0.88 [0.00-13.37] vs. 4.19 [0.96-21.61], p = 0.00003), BFU-E (0.83 [0.00-12.72] vs. 8.81 [1. 38-32.51], p = 0.00001), and CFU-MIX (0.10 [0.00-1.70] vs. 0.56 [0. 00-2.64], p = 0.001134) were significantly higher in the second peripheral blood HPC collection. However, yields per apheresis during the second collection did not significantly differ in the two groups. Six patients in Group 1 and 18 in Group 2 underwent transplantation, and all but one achieved engraftment, with a median of 15 versus 12 days to 1,000 neutrophils (NS), 22 versus 16 days to 1 percent reticulocytes (NS), and 26 versus 26 days to 20,000 platelets (NS), respectively. However, platelet engraftment was particularly delayed in many patients. CONCLUSION: G-CSF at 10 microg per kg alone may constitute a valid alternative to chemotherapy and G-CSF to obtain adequate numbers of peripheral blood HPCs in patients who previously failed to achieve mobilization with chemotherapy and G-CSF. This strategy should be tested in prospective randomized trials.     

Factors affecting mobilization of CD34+ cells in normal donors treated with filgrastim

BACKGROUND: Multiple days of apheresis are required for some normal peripheral blood progenitor cell (PBPC) donors, to ensure a sufficient collection of CD34+ cells for allografting. It would be of practical value to be able to identify the patients with poor mobilization on the basis of simple pretreatment clinical or hematologic variables. STUDY DESIGN AND METHODS: Clinical characteristics and laboratory data for 119 normal PBPC donors who underwent apheresis on Days 4 to 6 of treatment with granulocyte-colony-stimulating factor (filgrastim) were analyzed for correlations with CD34+ cell yield from the first day of apheresis. RESULTS: The CD34+ cell yield was significantly lower in donors who were more than 55 years of age, who underwent apheresis on Day 4 of filgrastim therapy, or who were not obese. There were weak direct correlations between CD34+ cell yield and the baseline white cell count, preapheresis white cell count, and preapheresis mononuclear cell count, and there was a weak inverse correlation with age. Twenty- one donors (18%) were considered to have poor mobilization (< 20 × 10(6) CD34+ cells/L blood processed). In the multivariate analysis, the only significant factor was age greater than 55 years, which conferred a 3.8 times greater risk (95% CI, 1.1-13.7) of poor mobilization (p = 0.04). However, poor mobilization occurred in all age groups, so the predictive value of the model was low. CONCLUSION: Donor variables correlated with CD34+ cell yield only weakly, so no particular clinical characteristic can be used to exclude an individual as a PBPC donor if he or she is otherwise suitable for the apheresis procedure.     

Hematologic recovery after autologous PBPC transplantation: importance of the number of postthaw CD34+ cells

BACKGROUND: The implementation of a quality-assurance program is a major requirement to ensure quality and safety of the final PBPC components intended for clinical use. It is not clear whether the quantification of CFU-GM and CD34+ cells should be done on fresh components and after cryopreservation, which better represents the actual composition of the graft. STUDY DESIGN AND METHODS: Correlation between prefreeze and postthaw MNCs, CD34+ cells, and CFU-GM collected from 126 patients undergoing BMT (n=43) or PBPC (n =83) transplantation were evaluated. The statistical incidence of prefreeze and postthaw parameters as well as patient characteristics and conditioning regimens on hematologic recovery were analyzed. RESULTS: By multivariate analysis, prefreeze and postthaw CD34+ cells were the only two variables significantly and independently correlated to hematologic recovery. Low prefreeze and postthaw CD34+ cell numbers associated to a low CD34+ yield characterize PBPC grafts from patients who have the slowest hematologic recovery. The postthaw PBPC CD34+ cell number can be estimated before conditioning regimen by thawing a small aliquot of the graft. CONCLUSION: In association to prefreeze CD34+ cell number and to CD34+ yield, postthaw CD34+ cell number may be useful in monitoring cell loss during processing and identifying patients at risk of slow PBPC engraftment.     

In leukapheresis products from non-Hodgkin's lymphoma patients, the immature hematopoietic progenitors show higher CD90 and CD34 antigenic expression.

Damage to the stem cell progenitors caused by the chemotherapy received in patients diagnosed with non-Hodgkin's lymphoma (NHL) may be an important factor limiting progenitor cell mobilization. The aim of the present analysis was to evaluate the effect of the chemotherapy on the different progenitor cell subpopulations obtained in the leukapheresis. For this purpose, a combination of immunophenotype and functional assays has been performed in 26 mobilized peripheral blood (PB) samples from NHL patients and 36 healthy donors. The different progenitor subpopulations analyzed by flow cytometry significantly correlated with the corresponding populations assessed by functional assays in both healthy donors and NHL patients (p<0.05, r>0.5). The number of committed CFU-GM was similar in both groups (p=0.246), but we found significant decrease in the number of BFU-E and more immature progenitors in PB from NHL patients as compared to donors (p<0.05). Moreover, the number of total CFU was significantly lower in NHL patients (p=0.007). Accordingly, CD34+ cells (p=0.018) and CD34+ subpopulations was decreased in NHL patients. Nevertheless, CD90 and CD34 intensity was significantly higher within CD34+ cells from NHL patients as compared to donors. However, although numerically reduced non-committed CD34+ cells are more immature in chemotherapy mobilized NHL patients. In summary, our results show that all NHL hematopoietic progenitors, analyzed by both immunophenotypical and functional approaches, are impaired in leukapheresis products.     

Expansion of mobilized peripheral blood progenitor cells under defined culture conditions rsing CD34+CD71-CD45- cells as a starting population

A major goal of experimental and clinical hematology is the identification of mechanisms and conditions supporting the expansion of transplantable hematopoietic stem cells. We assessed the expansion potential of CD34+CD71-CD45- cells derived from granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood under recently defined serum-free culture conditions. The CD34+CD71-CD45- cells in mobilized peripheral blood were found to contain the majority (92%+/-5.6) of primitive long-term culture initiating cells (LTCIC) and 53.5%+/-16.7 of the more committed colony-forming cells (CFC). Furthermore, this population represents 23.3%+/-4.1 of the total CD34+ cells and allows reduction of the cell density important for maintenance/expansion of primitive progenitor cells. CD34+ CD71- CD45- cells were cultured in defined serum-free media supplemented with 300 ng each of Flt-3 ligand and stem cell factor (SCF), 60 ng of interleukin (IL)-3, and 20 ng each of IL-6 and G-CSF. Mononuclear cells (MNC) and CFC were expanded 50-fold and 200-fold, respectively; primitive progenitor cells (LTC-IC) were maintained at input values after a total of 10 days of expansion. The addition of IL-15 to our cytokine cocktail expanded LTC-IC 2- to 3-fold and CFC to >500-fold. The data presented should allow clinical manipulation (purging) and expansion procedures with mobilized PBPC harvests without the loss of primitive progenitor cells and could be made applicable for large-scale clinical expansion.     

The efficiency of PBPC collections and the relationship to the precollection concentration of CD 34+ cells in blood

Transplantations of peripheral blood progenitor cells (PBPC) are able to assure a complete haematopoietic and immunologic reconstitution. The efficient mobilization of progenitor cells into peripheral blood is the main factor responsible for quality of the graft as well as timing and technique of collections. The aim of the present paper was to find the optimum time for starting PBPC collections and consequently to minimize the number of procedures required. The study was performed in patients with haematological malignancies using an autologous collection regimen. We attempted to determine a relationship between the concentration of CD 34+ cells in peripheral blood at the beginning of the collection and the number of CD 34+ cells in the leukapheresis product prepared in the standard mode processing 2-3 total blood volumes. We assessed the significance of the CD 34+ cells concentration in peripheral blood for the adequate collection of CD 34+ cells. We also evaluated the time of engraftment in patients after autologous PBPC transplantation whenever possible. The study was performed in 70 patients. Two groups were defined: Group I patients were well mobilized, whereas Group II patients were weakly mobilized. CD 34+ counts, using flow cytometry were found to be useful in predicting the optimal time for collections.     

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.     

Second mobilization and collection of peripheral blood progenitor cells in healthy donors is associated with lower CD34(+) cell yields

We have retrospectively evaluated the results of two cycles of mobilization and collection of peripheral blood progenitor cells (PBPC) from 46 healthy donors included in the Spanish National Donor Registry. Mobilization involved the administration of granulocyte colony-stimulating factor (G-CSF) at a median dose of 10 microg/kg per day, and apheresis was begun after the fourth dose of G-CSF in both cycles. The median interval between both mobilizations was 187 days (range, 7-1428 days). The incidence and types of side-effects were similar after both donations, with 25 and 26 donors developing some toxicity after the first and second donations, respectively. The median number of CD34(+) cells collected was higher after the first mobilization than after the second (5.15 versus 3.16 x 10(6)/kg, respectively; p = 0.05), and 29 donors yielded fewer CD34(+) cells after the second mobilization (p = 0.018). A lower proportion of donors yielded CD34(+) cell counts >4 x 10(6)/kg after the second cycle than after the first (52% versus 76%, respectively; p = 0.057). Our study shows that second rounds of PBPC collection from normal donors are well tolerated but are associated with a significantly reduced number of CD34(+) cells collected when the same mobilization scheme is used.     

CD34+ cell adhesion molecule profiles differ between patients mobilized with granulocyte-colony-stimulating factor alone and chemotherapy followed by granulocyte-colony-stimulating factor

BACKGROUND: High-dose therapy with autologous peripheral blood progenitor cell support is widely utilized but requires successful CD34+ cell mobilization and collection. Chemotherapy plus growth factors appear to mobilize more CD34+ cells than growth factors alone. Because alterations in expression of adhesion molecules are important in the trafficking of hematopoietic progenitors, the possibility was explored that the mechanism of this superior mobilization may be greater down regulation of adhesion molecules. STUDY DESIGN AND METHODS: The expression of eight adhesion molecules (CD11a, b, and c; 15s; 49d and e; 54; and 62L) on the collected CD34+ cells from 15 patients undergoing mobilization with chemotherapy plus granulocyte-colony-stimulating factor (G-CSF) was compared with those of 14 concomitant patients receiving G-CSF alone. RESULTS: Patients receiving chemotherapy plus G-CSF mobilized more CD34+ cells and did not differ in prior chemotherapy or radiation. There were no significant differences in the percentage of CD34+ cells expressing any of the adhesion molecules examined between the two groups. The chemotherapy plus G-CSF-mobilized cells consistently showed higher expression intensity, and this showed significance or a strong trend for CD11a and c, CD15s, and CD54. Despite these higher expression levels, there were no differences in engraftment kinetics. CONCLUSIONS: CD34+ cells mobilized by chemotherapy plus growth factors appear to have higher intensities of expression of several adhesion molecules. The significance of this observation will require further study.     

外周血CD34+细胞绝对计数可靠预示自体外周血干细胞采集效果

目的　为确定外周血CD34+细胞绝对计数能否可靠预示自体外周血干细胞的采集效果。方法　用流式细胞仪ProCOUNT方法对采集的 2 5份次移植物和采集当天外周血行CD34+细胞绝对计数 ,同时做外周血常规检查和移植物集落形成单位 (CFU)计数 ,每份次移植物以CD34+/kg ,单个核细胞 (MNC) /kg,粒 巨噬细胞集落形成单位 (CFU GM) /kg ,红细胞集落形成单位 (CFU E) /kg等为指标 ,与患者采集当天的外周血CD34+细胞绝对计数、CD34+细胞百分比、WBC ,MNC ,中性粒细胞(NEU)或血小板 (PLT)等各项指标进行相关分析和逐步回归分析。结果　 ( 1)Spearman相关分析结果 :外周血CD34+细胞绝对计数与移植物CD34+/kg高度相关 (r=0 790 ,P <0 0 0 1) ,外周血CD34+细胞百分比与移植物CD34+/kg相关 (r=0 6 17,P <0 0 5 )。外周血WBC、MNC、NEU、PLT或RBC与移植物CD34+/kg无关。外周血CD34+细胞绝对计数与移植物CFU E相关 ,而与CFU GM无关。外周血MNC与移植物MNC/kg相关。 ( 2 )逐步回归分析结果 :移植物CD34+/kg只与外周血CD34+细胞绝对计数高度相关 (P <0 0 0 1) ,而与外周血CD34+细胞百分比无关。结论　移植物CD34+/kg只与外周血CD34+细胞绝对计数高度相关 ,外周血CD34+细胞绝对计数能够可靠预示自体外周血干细胞的采集效果     

A single dose of 6 or 12 mg of pegfilgrastim for peripheral blood progenitor cell mobilization results in similar yields of CD34+ progenitors in patients with multiple myeloma

BACKGROUND: Current regimens for peripheral blood progenitor cell (PBPC) mobilization in patients with multiple myeloma are based on daily subcutaneous injections of granulocyte-colony-stimulating factor (G-CSF) starting shortly after cytotoxic therapy. Recently a polyethylene glycol-conjugated G-CSF (pegfilgrastim) was introduced that has a substantially longer t(1/2) than the original formula. STUDY DESIGN AND METHODS: The use of pegfilgrastim was examined at two dose levels for PBPC mobilization in patients with Stage II or III multiple myeloma. Four days after cytotoxic therapy with cyclophosphamide (4 g/m(2)), a single dose of either 6 mg pegfilgrastim (n = 15) or 12 mg pegfilgrastim (n = 15) or daily doses of 8 microg per kg unconjugated G-CSF (n = 15) were administered. The number of circulating CD34+ cells was determined during white blood cell (WBC) recovery, and PBPC harvesting was performed by large-volume apheresis. RESULTS: Pegfilgrastim was equally potent at 6 and 12 mg with regard to mobilization and yield of CD34+ cells. No dose dependence was observed because CD34+ cell concentration peaks were 131 and 85 per microL, respectively, and CD34+ cell yield was 10.2 x 10(6) and 7.4 x 10(6) per kg of body weight, respectively. Pegfilgrastim in either dose was associated with a more rapid WBC recovery (p = 0.03) and an earlier performance of the first apheresis procedure (p < 0.05) in comparison to unconjugated G-CSF. No difference regarding CD34+ cell maximum and yield could be observed. CONCLUSION: A single dose of 6 mg pegfilgrastim is equally potent as 12 mg for mobilization and harvest of PBPCs in patients with multiple myeloma. Because no dose dependency was seen at these dose levels, this might be also true for even smaller doses.