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.     

PBPC mobilization with paclitaxel, ifosfamide, and G-CSF with or without amifostine: results of a prospective randomized trial

BACKGROUND: The impact of amifostine on PBPC mobilization with paclitaxel and ifosfamide plus G-CSF was assessed. STUDY DESIGN AND METHODS: Forty patients with a median age of 34 years (range, 19-53) who had germ cell tumor were evaluated for high-dose chemotherapy. Patients were randomly assigned to receive either a single 500-mg dose of amifostine (Group A, n = 20) or no amifostine (Group B, n = 20) before mobilization chemotherapy with paclitaxel (175 mg/m(2)) given over 3 hours and ifosfamide (5 g/m(2)) given over 24 hours (TI) on Day 1. G-CSF at 10 microg per kg per day was given subsequent to TI with or without amifostine from Day 3 until the end of leukapheresis procedures. RESULTS: In 2 (10%) of 20 patients receiving amifostine and 3 (15%) of 20 patients not receiving it, no PBPC separation was performed because of mobilization failure. No significant differences were observed in the study arms with regard to the time from chemotherapy until first PBPC collection or the number of apheresis procedures needed to harvest more than 2.5 x 10(6) CD34+ cells per kg. Furthermore, leukapheresis procedures yielded comparable doses of CD34+ cells per kg (3.4 x 10(6) vs. 3.6 x 10(6); p = 0.82), MNCs per kg (2.7 x 10(8) vs. 2.6 x 10(8); p = 0.18), and CFU-GM per kg (15.9 x 10(4) vs. 19.3 x 10(4); p = 0.20). Patients in Group A had higher numbers of circulating CD34+ cells on Day 10 (103.0/microL vs. 46.8/microL; p = 0.10) and on Day 11 (63.0/microL vs.14.3/microL; p = 0.04) than did patients in Group B. CONCLUSION: Administration of a single dose of amifostine before chemotherapy with TI mobilized higher numbers of CD34 cells in the circulation, but did not enhance the overall collection efficiency in the present trial.     

Comparison of intermittent- and continuous-flow cell separators for the collection of autologous peripheral blood progenitor cells in patients with hematologic malignancies

BACKGROUND: The transplantation of autologous peripheral blood progenitor cells (PBPCs) after high-dose chemotherapy is a valuable therapy for patients with hematologic and solid malignancies. Several methods are used for harvesting PBPCs. The efficiency of intermittent- and continuous-flow blood cell separators in collecting progenitor cells from the blood of patients undergoing myeloablative treatment for cancer was compared. STUDY DESIGN AND METHODS: PBPC components (n = 133) were obtained from 72 patients by leukapheresis with continuous-flow machines (Spectra, COBE; CS 3000 Plus, Baxter) and with an intermittent-flow machine (MCS 3P, Haemonetics). The data were analyzed retrospectively. Blood samples obtained from the patients before leukapheresis and samples of the leukapheresis components themselves were analyzed for their content of RBCs, WBCs, platelets, and CD34+ cells. RESULTS: The Spectra processed more than twice the blood volume in the shortest time (15 L in 178 min), whereas the Baxter CS 3000 Plus (10 L in 185 min) and the MCS 3P (4.8 L in 239 min) processed significantly smaller volumes in a longer time. The mean ACD consumption was 403 mL with the MCS 3P, 900 mL with the CS 3000 Plus, and 1000 mL with the Spectra. The product volumes were 50 mL (CS 3000 Plus), 69 mL (MCS 3P), and 166 mL (Spectra). In all groups, differences in the preapheresis hemograms were not significant, but the Spectra group had fewer CD34+ cells than the other groups. Despite this, the differences in the number of CD34+ cells in the leukapheresis components of all groups were without statistical significance. In the Spectra group, the collection of MNCs of 104 percent and CD34+ cells of 154 percent was significantly more efficient than that in the MCS 3P group (42.2% and 56%, respectively) or the CS 3000 Plus group (50.8% and 47.15%) as related to the patients' blood volume. CONCLUSION: PBPC collection can be performed successfully with continuous-flow and intermittent-flow blood cell separators. The Spectra had the best recovery of CD34+ cells within the shortest time. Leukapheresis with the MCS 3P is indicated if only a single venous access is available.     

Improved collection of mobilized CD34+ hematopoietic progenitor cells by a novel automated leukapheresis system

BACKGROUND: For simplification of blood cell transplantation, an automated apheresis system that exploits a dual-stage channel device for mononuclear cell (MNC) collection (Au-toPBSC, designed for the COBE Spectra) was studied. STUDY DESIGN AND METHODS: The automated default software (AutoPBSC-Default) and three software modifications of the harvest frequency during leukapheresis, referred to as Au-toPBSC-1.25, AutoPBSC-1.75, and AutoPBSC-2.75, were evaluated in comparison with the semiautomated Version 4.7 (V4.7) apheresis system in 119 leukapheresis procedures performed in 90 cancer patients treated with chemotherapy plus granulocyte–colony-stimulating factor. CD34+ cell and platelet collection efficiency (CE); volume and cell composition of the leukapheresis components; and patient platelet and red cell (RBC) loss during leukapheresis were measured. RESULTS: The majority of collection measures evaluated with the AutoPBSC compared favorably to those obtained with the V4.7. CD34+ cell CE increased from 55 percent with V4.7 to 68 percent with the AutoPBSC-Default (p = 0.05). The AutoPBSC provided lower platelet contamination in the collected component (1.18 × 10¹¹ vs. 2.26 × 10′′ with the V4.7;p< 0.001). The volume of the AutoPBSC-Default component was significantly lower (67 vs. 180 mL with the V4.7; p<0.001). The MNC purity of the AutoPBSC component was greater (52 vs. 28% with the V4.7; p<0.001), and the RBC contamination lower (AutoPBSC, 0.53 × 10¹¹ vs. 1.04 × 10¹¹ with the V4.7; p<0.001). Modifications of the AutoPBSC to increase the harvest frequency by 1.25-, 1.75-, and 2.75-fold resulted in increased CD34+ cell CE (77%, 75%, and 83%, respectively; p<0.001 in all cases), but also in reduced numbers of circulating platelets, higher platelet contamination of the component, and lower MNC purity than were seen with the AutoPBSC-Default. CONCLUSION: The AutoPBSC offers the following advantages over the V4.7 system: a) better CE of CD34+ cells; b) reduced collection of platelets; c) reduced contamination of the leukapheresis component with granulocytes, platelets, and RBCs; d) reduced component volume; and e) automation.     

Immune reconstitution after autologous selected peripheral blood progenitor cell transplantation: comparison of two CD34+ cell-selection systems

BACKGROUND: Selection of CD34+ PBPCs has been applied as a method of reducing graft contamination from neoplastic cells. This procedure seems to delay lymphocyte recovery, while myeloid engraftment is no different from that with unselected PBPC transplants. STUDY DESIGN AND METHODS: Lymphocyte recovery was studied in two groups of patients who underwent autologous CD34+ PBPC transplant with two different technologies (Ceprate SC, Cellpro [n = 17]; CliniMACS, Miltenyi Biotech [n = 13]). The median number of CD34+ cells transfused was 3.88 x 10(6) per kg and 3.32 x 10(6) per kg, respectively. Residual CD3 cells x 10(6) per kg were 4.97 and 0.58, respectively (p = 0.041). Residual CD19 cells x 10(6) per kg were 1.33 and 0.73, respectively (NS). RESULTS: No differences were found between the two groups in total lymphocyte recovery to >0.5 x 10(9) per L, which achieved a stable count by Day 30. During the study period, the CD4+ cell count remained below 0.2 x 10(9) per L, and the B-cell subset showed a trend toward normalization. CD3/HLA-DR+ and CD16/56 increased markedly in both groups by Day 30. An increase in CMV (13%) and adenovirus (17.4%) infection was found in both groups. CONCLUSION: Both CD34+ cell selection technologies used here determined an excellent CD34+ cell purity and an optimal depletion of T cells. The high rate of viral complications is probably due to the inability of residual T cells left from the CD34+ cell selection to generate, immediately after transplant, an adequate number of virus-specific lymphocytes.     

Comparison of CD34+ cell collection on the CS-3000+ and Amicus blood cell separators

BACKGROUND: Mobilized PBPCs, detectable on the basis of CD34 expression, can be collected on various cell separators. The CD34+ cell collection efficiencies of two cell separators (CS-3000+ and Amicus, Baxter) were tested on two comparable groups of oncology patients. STUDY DESIGN AND METHODS: Leukapheresis assisted by the standard manufacturer's software and variables settings was performed in 37 (CS-3000+) and 34 (Amicus) patients (total of 83 and 67 collections, respectively) after chemotherapy plus G-CSF treatment. RESULTS: The total CD34+ cell count per leukapheresis components as well as per kg of patient's body weight were twofold higher by using the Amicus than the CS-3000+ device. Platelet contamination in Amicus components was twice as low compared to the CS3000+. Mean Amicus CD34+ collection efficiency (CD34+eff) (54.9 +/- 27.2%) was significantly higher (p < 0.015) than the CS-3000+ (46.4 +/- 16.7%) one. However, Amicus CD34+eff decreased progressively as the peripheral blood CD34+ concentrations increases over 200 CD34+ cells per microL. A parallel increase in the WBC counts in these cases seems to be the principal cause of decrease in CD34+eff (evident for WBCs >40 x 10(3)/microL and most pronounced for WBCs >60 x 10(3)/microL). CONCLUSIONS: Mean CD34+eff and CD34+ cell yields were better on Amicus than on CS-3000+. CD34+eff of Amicus, however, seems to be related to the initial WBC counts, decreasing progressively when WBC increased over 4 x 10(3) per microL that coincided with the increase in CD34+ cell concentrations. For these cases, the volume and duration of cycles should be adapted to optimize CD34+ collections by using Amicus separators.     

Minimal number of circulating CD34+ cells to ensure successful leukapheresis and engraftment in autologous peripheral blood progenitor cell transplantation

BACKGROUND: The number of peripheral blood (PB) CD34+ cells has been widely used to monitor the timing of leukapheresis for autologous transplantation. However, no cutoff value for CD34+ cells in PB has been defined as a guideline for the identification of patients in whom the harvest would be effective and those in whom there was a high probability of failure. STUDY DESIGN AND METHODS: The present study investigated the best threshold of CD34+ cells in PB for successful harvesting and engraftment, using 263 PB samples with their corresponding leukapheresis components. In addition, that measure has been compared to other commonly used criteria such as the white cell count, the number of mononuclear cells, and the number of colony- forming units-granulocyte macrophage in PB. RESULTS : Time to engraftment of both granulocytes and platelets was significantly influenced by the number of CD34+ cells transfused, but all patients receiving > or = 0.75 × 10(6) CD34+ cells per kg achieved engraftment within a reasonable number of days (> 0.5 × 10(9)/L granulocytes by Day 11 and > 20 × 10(9)/L platelets by Day 13). A clear correlation between the number of CD34+ cells per microL in PB and of CD34+ cells per kg collected was found at each apheresis (r = 0.9, p < 0.0001). Moreover, the number of CD34+ cells per microL measured in PB the day the first leukapheresis was initiated displayed an excellent correlation with the total amount of CD34+ cells per kg finally collected (r = 0.81, p < 0.0001). On the basis of the regression curve obtained and the clinical engraftment results, it was found that the presence of > 5 CD34+ cells per microL in PB ensured a good yield from the harvest in 95 percent of patients and would avoid an unsuccessful harvest in 81 percent of cases. CONCLUSION: A dose of only 0.75 × 10(6) CD34+ cells per kg guarantees hematopoietic recovery within a reasonable number of days. To initiate a leukapheresis from which enough progenitor cells may confidently be obtained, a minimum of 5 CD34+ cells per microL in PB is required.     

Isolation of CD34+ progenitor cells from peripheral blood by use of an automated immunomagnetic selection system: factors affecting the results

BACKGROUND: The isolation of CD34+ cells from mobilized peripheral blood is being increasingly used in the setting of allogeneic or autologous hematopoietic cell transplantation. Investigation of variables that may influence the effectiveness of CD34+ cell selection is of interest. STUDY DESIGN AND METHODS: Fifty-one CD34+ cell selections from peripheral blood progenitor cells (PBPCs) (39 allogeneic and 12 autologous) were performed using a magnetic cell separator (Isolex 300i, Baxter), including version 2.0 software. The results obtained were analyzed for different processing variables. The feasibility of transplanting these isolated CD34+ cells was also analyzed. RESULTS: The isolated CD34+ cell fraction had a median purity of 88.9 percent (range, 47.8-98.3). The median recovery of CD34+ cells was 45.1 percent (13.8-76.2), and the median colony-forming unit- granulocyte-macrophage (CFU-GM) content was 17. 2 percent (0.8-58.6). Logarithms of T- and B-cell depletion had median values of 3.7 and 2.8, respectively. The version 2.0 software of the Isolex 300i gave a higher CD34+ cell recovery in the enriched cell fraction (median 57.8%) than did version 1.11 (39.4%) or 1.12 (44.4%) (p = 0.01). The use of recombinant human deoxyribonuclease I during cell processing yielded more CD34+ cells (53% vs. 41%, p = 0. 01) and higher purity (92.8% vs. 87%, p = 0.03). There was a correlation between the percentage of CD34+ cells labeled with the monoclonal antibody 8G12 clone and the percentage of CD34+ cells labeled with the monoclonal antibody used during the processing technique (9C5 clone) in the initial, enriched, and depleted CD34+ cell fractions (R(2) = 0.95; 0.92; 0.78, p< 0.005, respectively). Median times for recovering >0.5 x 10(9) per L of granulocytes and >20 x 10(9) per L of platelets were 13 and 16 days in the allograft patients and 13 and 14 days in the autograft patients. CONCLUSION: CD34+ cells can be highly and effectively isolated from allogeneic and autologous grafts by use of this automated technique, with a high grade of T- and B-cell depletion. These purified CD34+ cell components can engraft normally.     

Comparison of volumetric capillary cytometry with standard flow cytometry for routine enumeration of CD34+ cells

BACKGROUND: This study assesses the feasibility of a new volumetric cytometry system for the enumeration of CD34+ cells in apheresis components, peripheral blood, and cord blood samples in routine laboratory work. This system is compared with the following flow cytometry protocols: Milan, ISHAGE, ISHAGE with 7-AAD, and flow-count fluorospheres. STUDY DESIGN AND METHODS: Correlation, linearity, and reproducibility studies were performed for the various methods. Clonogenic cultures were performed, as an external control, to assess the correlation between the number of CD34+ cells per microL and the number of colony-forming units per microL. RESULTS: The linear regression analysis demonstrated that the five methods were comparable (R2 ranged from 0.86 to 0.96 and slopes were close to 1). The CD34+ assay and the flow-count methods showed poor linearity for CD34+ cell counts below 10 cells per microL (R2 = 0.46 and 0.47). The reproducibility assay for a CD34+ count of 10 cells per microL showed a CV of 12 percent and 25 percent for the Milan and CD34+ assay methods, respectively. The mean CV among all five methods for the 46 evaluated samples was 20 percent. There was a strong correlation between the number of CD34+ cells per microL and colony-forming units per microL in cord blood and apheresis samples (r = 0.71-0.81). CONCLUSION: The CD34+ assay is useful in CD34 enumeration in cord blood, leukapheresis samples, and peripheral blood samples and provides comparable results to the Milan, ISHAGE, ISHAGE with 7-AAD, and flow-count methods. Nevertheless, peripheral blood samples with low CD34 absolute counts (below 10 cells/microL) should be analyzed by alternative flow cytometry protocols. Even though the same operator performed the study in a single laboratory, the high inter-method CV suggests that differences in sample preparation and gating strategy are factors that increase variability. Protocols with fewer intermediate steps or fully automated protocols such as the CD34+ assay are expected to reduced intra- and inter-laboratory variability.     

The predictive value of white cell or CD34+ cell count in the peripheral blood for timing apheresis and maximizing yield

BACKGROUND: The collection of peripheral blood stem and progenitor cells (PBPCs) for transplantation can be time-consuming and expensive. Thus, the utility of counting CD34+ cells and white cells (WBCs) in the peripheral blood was evaluated as a predictor of CD34+ cell yield in the apheresis component. STUDY DESIGN AND METHODS: The WBC and CD34+ cell counts in the peripheral blood and the apheresis components from 216 collections were assessed. Sixty-three patients underwent mobilization with chemotherapy plus filgrastim, and 17 patients and 14 allogeneic PBPC donors did so with filgrastim alone. The relationship between the number of WBC and CD34+ cells in the peripheral blood and in the apheresis component was analyzed by using rank correlation and linear regression analysis. RESULTS: The correlation coefficient for CD34+ cells per liter of peripheral blood with CD34+ cell yield (x 10(6)/kg) was 0.87 (n = 216 collections). This correlation existed for many patient and collection variables. However, patients with acute myeloid leukemia had fewer CD34+ cells in the apheresis component at any level of peripheral blood CD34+ cell count. Components collected from patients with CD34+ cell counts below 10 x 10(6) per L in the peripheral blood contained a median of 0.75 x 10(6) CD34+ cells per kg. When the WBC count in the blood was below 5.0 x 10(9) per L, the median number of CD34+ cells in the peripheral blood was 5.6 x 10(6) per L (range, 1.0-15.5 x 10(6)/L). A very poor correlation was found between the WBC count in the blood and the CD34+ cell yield (p = 0.12, n = 158 collections). CONCLUSION: The number of CD34+ cells, but not WBCs, in the peripheral blood can be used as a predictor for timing of apheresis and estimating PBPC yield. This is a robust relationship not affected by a variety of patient and collection factors except the diagnosis of acute myeloid leukemia. Patients who undergo mobilization with chemotherapy and filgrastim also should undergo monitoring of peripheral blood CD34+ cell counts, beginning when the WBC count in the blood exceeds 1.0 to 5.0 x 10(9) per L.     

AutoPBSC程序与MNC程序采集外周血造血干细胞的比较研究

目的比较COBE Spectra血细胞分离系统的自动采集程序(AutoPBSC程序)与4.7版半自动采集程序(MNC程序)采集健康供者外周血造血干细胞的差异及对供者血常规相关指标的影响。方法 2002年3月~2008年3月期间对53例健康供者随机采用Auto PBSC程序和MNC程序进行了113例次造血干细胞采集,其中采用AutoPBSC程序63例次,MNC程序50例次。分析比较2种程序采得外周血造血干细胞(PBSC)的采集体积、单个核细胞百分数及总数、CD34+细胞百分数及总数等指标,采集前后供者红细胞、血小板变化。结果 2种程序采集外周血造血干细胞的体积、单个核细胞百分数、CD34+细胞百分数、CD34+细胞总数、采集袋中血小板及红细胞混入量、采集前后供者血小板计数的变化存在显著性差异(P<0.01);2种程序采集的单个核细胞总数无显著性差异;血小板计数在应用MNC程序组呈下降趋势,较AutoPBSC程序更加明显(P<0.01);1例地中海贫血供者应用Auto PBSC程序采集失败。结论 2种程序均可有效采集外周血造血干细胞,与MNC程序比较AutoPBSC程序具有以下优势:单个核细胞和CD34+细胞百分数提高、采集物体积减少有利于采集物的冻存、采集物中血小板数少对供者血小板影响小。地中海贫血供者需慎用Auto PBSC程序。     

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.     

动员外周血CD34阳性细胞流式细胞术测定中的策略探讨

探索用流式细胞术测定动员外周血中CD34^ 细胞的简便有效的方法，以便在干细胞动员中进行有效的动态监测，及时收取干细胞，把握最佳移植效果，将经药物动员的移植供的外周血用CD34和CD45荧光抗体标记，用红细胞裂解液将红细胞裂解后经流式细胞仪检测，运用恰当的分析窗口，有效的设门分析结合干细胞的生物学特性，确定CD34^ 细胞在窗口中的确切位置，统计CD34^ 细胞在有核细胞中的比例，结果表明，通过本方法可有效地测定0.05%-0.1%的CD34^ 细胞的相对含量，在药物动员的第5或6天，多数患外周血中CD34^ 细胞达到峰值，某些患外周血中CD34^ 细胞可超过1%，结论：通过标记中的有效阻断和多参数分析，本方法可对动员外周血中微量的CD34^ 细胞进行有效的动态监测，对适时采集干细胞进行移植提供了重要的参考。     

Cobe Spectra与Fenwal CS 3000 Plus血细胞分离器外周血造血干/祖细胞的采集效能比较

为了评价Cobe Spectra(Version6.1)和Fenwal CS 3000 Plus两种血细胞分离机在造血干／祖细胞采集中的采集效能，对36人64次外周血造血干／祖细胞的采集进行了回顾性分析．20人42次使用Cobe Spectra采集，16人22次使用Fenwal CS 3000 Plus采集对CD34^ 细胞采集量、采集效率以及红细胞与血小板的采集量进行比较，结果表明：Cobe Spectra和Fenwal CS 3000 Plus在CD34^ 细胞采集量和采集效率上无显著差异?CD34^ 细胞采集量与供者白细胞、单核细胞、造血祖细胞、CD34^ 细胞的动员情况呈正相关，在多因素stepwise线性回归模型中，采集前外周血干／祖细胞浓度是唯一有意义的影响因素，Fenwal CS 3000 Plus的采集效率与外周血单核细胞量呈负相关。Fenwal CS 3000 Plus对红细胞的收集量显著高于Cobe Spectra，并且采集后供者外周血血小板降低程度较Cobe Spectra更严重。结论：Cobe Spectra(Version 6．1)和Fenwal CS 3000 Plus在CD34^ 细胞的采集能力上无显著差别。当外周血单核细胞数量高，或是血型不合移植的及血小板减少的供者，推荐使用Cobe Spectra血细胞分离机.     

Determining factors predictive of CD34+ cell collection efficiency in an effort to avoid extended and repeated apheresis sessions

Introduction: Collection efficiency (CE) is a reflection of the proportion of cells passing through a cell separator that is harvested. The aim of our study was to evaluate which factors influence CE independently in order to find ways to improve CE and therefore minimize the costs and risks of leukapheresis and graft processing. Materials and Methods: A total of 206 consecutive apheresis procedures performed on 128 donors/patients were studied retrospectively. We explored the association between CE and the following factors: age, sex, weight, mobilization (granulocyte‐colony‐stimulating factor with or without chemotherapy), collection type (autologous versus allogeneic), venous access (peripheral versus central), total processed blood volume (TPV), hematocrit, white blood cell (WBC) count, thrombocyte count, and peripheral blood CD34+ cell concentration (PBCD34+). Results: Stepwise multiple regression analysis showed WBC count to be the single best predictor of CE, accompanied by TPV. When performing subgroup analysis for autologous apheresis procedures, the inverse correlation of WBC count and TPV with CE becomes stronger (r = ?0.563 with P < 0.001 and r = ?0.198 with P = 0.020 respectively), whereas those correlations disappear when analyzing only allogeneic apheresis procedures. Conclusion: The negative correlation between TPV and CE present only in autologous collection procedures can be explained by the limited intra‐apheresis recruitment of CD34+ cells into the blood which is negatively influenced by extensive pre‐treatment. As a result of this study we decided to limit TPV to a maximum of three times the patient's blood volume in autologous apheresis procedures at our center. J. Clin. Apheresis, 28:404–410, 2013. © 2013 Wiley Periodicals, Inc.     

Comparison of CD34+ cell collection efficiency on the COBE Spectra and Fenwal CS-3000 Plus

Optimal collections of mobilized CD34+ cells are important in terms of both patient toxicity and cost. The factors that determine CD34+ collection efficiency (CD34eff) of cell separators have not been well studied. In addition, because several cell separators are available, the type of collection device may also be a significant variable. Previous studies comparing the Baxter-Fenwal CS3000 and the COBE Spectra have not yielded consistent conclusions. Therefore, we retrospectively analyzed the collection outcomes of 163 consecutive donors with a peripheral CD34+ cell concentration (pCD34) of > or =5 cells/microl on the first collection that had been harvested on one or the other device. The CS3000 was found to yield a significantly higher CD34eff (50% vs. 39%, P = 0.006). However, donors were not balanced for several prognostic factors, which may contribute to CD34eff including mobilization with G-CSF vs. chemotherapy+G-CSF, average flow rate, and total volume of peripheral blood processed. When appropriate variables were included in a stepwise multiple variable analysis, cell separator type emerged as a significant independent predictive factor for CD34eff (P = 0.018). Our data indicates that the CS3000 will, on average, show a higher absolute CDeff of 8%. Furthermore, since the two devices differ in mechanism, prognostic factors may also differ. Comparisons suggest that peripheral blood WBC and hematocrit may be more important predictors for the CS3000.     

A new model for predicting the timing of leukapheresis on the basis of CD34+ cell and hematopoietic progenitor cell levels

We developed a model (depending on peripheral CD34(+) cell count and hematopoietic progenitor cell count) to determine the optimal timing of 3-day leukapheresis in patients pretreated with chemotherapy and G-CSF. Marrow potentials were identified on the basis of three patterns of leukapheretic yield. Pattern 1 predicted good marrow potential. The positive predictive value of a first-day leukapheretic yield of >1 x 10(6) CD34(+) cells/kg (mean 3-day yield = 8.18 x 10(6) CD34(+) cells/kg, n = 11) was 100%. Pattern 2 predicted poor marrow potential. The negative predictive value of a 3-day leukapheretic yield of >1 x 10(6) CD34(+) cells/kg (3-day yield = 0.26 x 10(6) CD34(+) cells/kg, n = 1) was 100%. Pattern 3 met neither of the above criteria (mean 3-day yield = 1.37 x 10(6) CD34(+) cells/kg, n = 19). The marrow potential was borderline and patients could be further divided into two subgroups according to peripheral CD34(+) cell counts when WBC reached >10,000/microl. The mean yield differed significantly between pattern 1 and 3 (P < 0.001). For patients with good marrow potential, leukapheresis should begin as soon as the WBC count is >5,000/microl. Patients with borderline marrow potential may benefit from delaying leukapheresis until the WBC level is >10,000/microl and leukapheresis extended more than 3 days.     

Immunomagnetic selection of CD34+ cells: factors influencing component purity and yield

BACKGROUND: In immunomagnetic selection of CD34+ cells from HPC transplants, not all factors that affect yield and purity of CD34+ cells are known. METHODS: Forty-three consecutive procedures of immunomagnetic selection of CD34+ cells from peripheral blood HPCs and bone marrow harvests (autologous harvests, n = 27; allogeneic harvests; n=16) were performed by use of a cell selection system (Isolex 300i, Baxter Immunotherapy). The composition of the starting component and the subsets of CD34+ cells were analyzed for correlation with the yield and purity of the final component. RESULTS: The mean purity of the final components was 84.3 percent (range, 27-99%), and the mean yield was 51.4 percent (range, 9.4-80. 4%). Partial regression analysis showed that, among the factors correlating with purity and/or yield, the RBC volume in the starting fraction had the highest predictive impact on the purity and yield of CD34+ cells, even after the exclusion of procedures using bone marrow harvests as an HPC source (beta coefficient, -0.704; p = 0. 001). CONCLUSION: The use of the Isolex 300i system allows efficient recovery of CD34+ cells in routine selection procedures. The volume of RBCs in the starting component should be minimized to ensure a high yield and purity of the final component.     

Collection of peripheral blood progenitor cells with an automated leukapheresis system

BACKGROUND: Apheresis devices designed for the collection of mature blood elements are being used for the collection of peripheral blood progenitor cells (PBPCs).The collection of PBPCs differs from that of other cells in the rarity of the target cell and in the fact that donors may undergo several days of collection. A consequence of this process may be a depletion of blood cells such as platelets from the blood. The disposable set and operating software for an apheresis device (Spectra, COBE BCT) was modified by the manufacturer to automate the collection of PBPCs and reduce the collection of unwanted blood cells. STUDY DESIGN AND METHODS: A study was initiated to compare the collection of PBPCs with the new device, the AutoPBSC (version [V]6.0 with AutoPBSC tubing set), and that with the MNC (mononuclear cell) procedure (V4.7 with white cell tubing set), for patients and healthy donors. RESULTS: Patients whose blood was processed by either theV6.0 orV4.7 procedure achieved the target dose of 5 x 10(6) CD34+ cells per kg of patient weight in similar numbers of procedures, even though the calculated collection efficiency for CD34+ cells using the automated V6.0 procedure was significantly less than that with the V4.7 procedure for both allogeneic donors and patients donating PBPCs. The collection efficiency for platelets was lower with the V6.0 procedure, and components collected in this manner contained fewer platelets. Apheresis by the V6.0 procedure required 30 to 60 more minutes per procedure than apheresis by the V4.7 procedure. Review of engraftment kinetics after transplantation did not reveal any effect of the collection procedure on recipients of either allogeneic or autologous transplants. CONCLUSION: The collection efficiencies of the V6.0 procedure for both CD34+ cells and mature blood cells are lower than those of the V4.7 procedure.The lower collection efficiency for platelets results in a smaller drop in peripheral blood platelet count after the procedure.The automated features of the V6.0 procedure may simplify PBPC collection, but this procedure requires a longer apheresis.     

Tempo of hematologic recovery correlates with peripheral blood CD34+ cell level in patients undergoing stem cell mobilization

This study was undertaken to evaluate the relationship between the time to recovery of peripheral blood counts and CD34+ cells in the peripheral blood (PB) and apheresis collections of patients undergoing intensive chemotherapy followed by rhG-CSF. Twenty-three patients with a median age of 42 years (range 17–64) with malignancies underwent peripheral blood stem cell (PBSC) collection after cyclophosphamide (CY) 4 g/m² and etoposide (600 mg/m²) followed by rhG-CSF (10 μg/kg/day). The WBC, platelet counts, CD34+ cell counts per ml of PB, and CD34+ cells in apheresis products were followed in all patients. The relationship of the time to recovery of WBC >1,000/μl, >3,000/μl, >10,000/μl and platelets >20,000/μl and 50,000/μl was compared to the average daily CD34+ cells/ml in each patient using the Spearman Correlation test. The tempo of recovery of WBC and platelets were highly correlated with the average CD34+ cell count in blood. In order to derive some useful guidelines for the timing of apheresis, the patients were divided into two groups, early recover (ER) and late recover (LR) based on the median time (day 10) to reach WBC count greater than 1,000/μl. ER patients had an average daily PB CD34+ cell count of 9.04 × 10⁴/ml (range 0.44–17.5) and a median yield of CD34+ cells of 10.43 × 10⁶/kg (range 0.60–25.95) compared to LR patients, who had 1.87 × 10⁴/ml (range 0.32–5.44) in the PB (P = .001) and a yield 3.20 × 10⁶/kg CD34+ cells (range 0.037–9.39) (P = .001). Patients recovering their WBC to 1,000/ml within 10 days of completing this regimen may undergo PBSC collection and achieve minimum-target cell doses of >2.5 × 10⁶ CD34+ cells/kg—100% of the time. J. Clin. Apheresis 13:1–6, 1998. © 1998 Wiley-Liss, Inc.