Collection of peripheral progenitor cells in paediatric patients with a new programme for the collection of mononuclear cells

When harvesting peripheral progenitor cells (PPC) in children, the special situation of their circulatory system has to be taken into account. Therefore, extracorporeal blood volume and product volume should be small to avoid side effects. Nine children (age 2-14 years, weight 12.8-58.5 kg) with malignancies underwent 10 PPC collections with the MNC programme of the Amicus blood cell separator. The disposable kit was primed with red blood cells (RBCs) or human albumin to avoid circulatory side effects. The children were monitored for blood pressure and heart rate during the whole apheresis procedure. A median blood volume of 4,577 ml (range 3,536-8,596 ml) was processed in a separation time of 270 min (range 176-331 min). The median product weight was 81 g (range 53-107 g) and the yield of CD 34 antigen expressing cells was 12.5 x 10(6)/kg body weight (range 1.8-26 x 10(6)/kg body weight). Only one child had to undergo a second apheresis to collect the desired transplantation dose. The median platelet contamination of the product was 0.32 x 10(11) (0.13-0.85 x 10(11)). No circulatory side effects were observed. Blood flow alarms occurred in seven of ten aphereses and one collection had to be terminated due to insufficient flow. PPC can be efficiently collected in children with the MNC programme without circulatory side effects. The platelet contamination of the product was low due to the elutriation principle of the collection process, thereby avoiding thrombocytopenic bleeding episodes in the patients.     

Hematopoietic progenitor cell large volume leukapheresis (LVL) on the Fenwal Amicus blood separator

A technique for large volume leukapheresis (LVL) for hematopoietic progenitor cell (HPC) collection using the Fenwal Amicus is presented. It was compared to standard collections (STD) with regard to CD34+ cell yields and cross-cellular content. Optimal cycle volumes and machine settings were evaluated for LVL procedures. A total of 68 patients underwent 80 HPC collection procedures. Because of differences in CD34+ cell yields associated with peripheral white blood cell counts (WBC), the comparison was divided into groups of 20 with WBC < or =35 x 10(9)/L (< or =35 K) and those >35 x 10(9)/L (>35 K). Baseline CD34+ cell counts (peripheral count when patient started HPC collection) were used (median 18-23 cells/microl). Significantly more whole blood (corrected for anticoagulant) was processed with LVL (LVL 20 l vs. STD 13.5 l). For < or =35 K, median CD34+ x 10(6), WBC x 10(9), RBC ml, Plt x 10(11) yields/collection were 183, 21.2, 14, 0.8, respectively, for STD vs. 307, 22.1, 11, 1.0, respectively, for LVL. For >35 K, median CD34+ x 10(6), WBC x 10(9), RBC ml, Plt x 10(11) yields/collection were 189, 32.7, 15, 1.4, respectively, for STD vs. 69, 40.8, 21, 1.3, respectively, for LVL. We have described a method of LVL using the Amicus that, in patients with pre-procedure WBC < or =35 x 10(9)/L, collects more CD34+ cells than a standard procedure with acceptable cross-cellular content. This method is not recommended when pre-procedure WBC counts are >35 x 10(9)/L.     

脐血CD34+细胞与单个核细胞的体外扩增特性研究

目的　探讨CD34+ 富集细胞和单个核细胞 (MNC)的体外扩增特性。方法　利用Min iMACS系统富集CD34+ 细胞 ,在相同条件下与同批MNC进行对照培养 ;观察了再次富选和MNC培养上清 (MNC SN)对CD34+ 富集细胞扩增的影响 ;并尝试了MNCCD34- 细胞的培养。结果　虽然CD34+ 富集细胞具有很高的扩增潜力 ,但在培养过程中 ,其集落密度和CD34 + 细胞含量却始终呈下降趋势 ,而MNC在培养中却出现了一个上升的趋势 ,集落密度和CD34+ 细胞含量分别由第 0天的 (4 12± 16 7) 10 5细胞和 (1.12± 0 .4 2 ) %增至第 7天的 (116 2± 5 6 6 ) 10 5细胞和 (4 .17± 1.4 4 ) % ;再次富选可以使培养过的CD34+ 富集细胞的总细胞和CD34+ 细胞扩增能力大大提高 ;MNCCD34- 细胞具有集落形成和转化为CD34+ 细胞的能力 ;MNC SN对CD34+ 富集细胞的集落形成有促进作用 ,而同时又对CD34+ 细胞有促分化作用。结论　CD34+ 富集细胞在体外大量扩增的同时存在大量分化 ,其在培养过程中产生的CD34-细胞对CD34+ 细胞的扩增有抑制作用 ;脐血MNC中大量的CD34- 细胞含有造血干 祖细胞 ,其分泌的细胞因子有促进CD34+ 细胞向较为成熟的集落形成祖细胞分化的作用。     

明胶酶A、B在脐血CD34+细胞及部分白血病细胞系中的表达

目的　研究骨髓及脐血CD34+ 细胞及白血病细胞系的明胶酶 ,即基质金属蛋白酶 9(MMP 9,明胶酶B)和基质金属蛋白酶 2 (MMP 2 ,明胶酶A)的产生 ,探讨它们在CD34+ 细胞迁移、归巢中的意义及在白血病发病中的作用。方法　通过MiniMACS磁珠分离技术分离脐血及骨髓的CD34+细胞 ,通过酶谱分析法测定脐血、骨髓CD34 + 细胞及白血病细胞系的无血清条件培养液中明胶酶的表达。结果　在脐血CD34+ 细胞的条件培养液中可测出相对分子质量为 92× 10 3的亮带 ,骨髓CD34+ 细胞的条件培养液中未测到亮带。部分白血病细胞系U937、KG 1a、HL 6 0可产生相对分子质量为 92×10 3和 72× 10 3的亮带 ,J6 1、J6 2细胞系可产生相对分子质量为 92× 10 3的亮带 ,而HEL、Namalva、CEM、K5 6 2、LCL H不产生亮带。结论　脐血CD34+ 细胞可产生MMP 9,而骨髓CD34+ 细胞不产生 ,脐血CD34+ 细胞具有较强的穿透基底膜的迁移能力并与MMP 9相关。在白血病细胞系中 ,部分髓系白血病细胞系产生MMP 9和MMP 2 ,而非髓系白血病细胞系不产生。     

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.     

地中海贫血患儿血清群体反应性抗体对脐血CD34~+细胞增殖和凋亡的影响

本研究探讨特异性群体反应性抗体(panel reactive antibody,PRA)对脐血CD34+细胞的影响。取含PRA的β地中海贫血患儿血清,与脐血CD34+细胞、补体联合孵育,观察其对CD34+细胞的影响,并以[3H]TdR掺入法测定细胞DNA合成及流式细胞仪检测细胞凋亡。结果表明,PRA血清组细胞培养上清中乳酸脱氢酶水平高于对照组;PRA血清组脐血CD34+细胞DNA合成能力较对照组下降。流式细胞仪检测显示,各实验组间脐血CD34+细胞凋亡率差异无统计学意义。结论:特异性PRA血清对脐血CD34+细胞的增殖有抑制作用,补体可增强上述作用;特异性PRA血清对脐血CD34+细胞的凋亡无明显影响。     

不同标记法及去红细胞法对检测微量脐血CD34+造血干细胞含量的影响

目的 采用ISHAGE(international society of hematotherapy and graft engineering)法和常用的CD34^ 造血干细胞流式检测方法对同一脐血样品进行比较实验，确定更适用于微量脐血CD34 ^ 造血干细胞含量检测的方法。方法 分别采用ISHAGE造血干细胞计数协会推荐方法、低渗NH4C1去红细胞CD45／CD34双色标记法(NH4C1双标法)、OptilyseC溶血剂去红细胞CD34单色标记法(OptilyseC单标法)、低渗NH4C1去红细胞CD34单色标记法(NH4C1单标法)、羟乙基淀粉沉淀去红细胞CD45／CD34双色标记法(HES双标法)检测脐血造血干细胞含量，并比较不同方法测得数据的差异。结果 8份脐血标本用ISHAGE方法测得CD34^ 造血干细胞含量的中位数为0．278％，NH4C1双标法测得结果为0．297％，与ISHAGE方法相比差异无显性。用HES双标、OptilyseC单标法和NH4C1单标法测得的结果分别为5．715％，0．391％和0．741％，与ISHAGE方法相比差异有显性。结论 ISHAGE方法是一种公认的准确性高，重复性好的检测造血干细胞方法。OptilyseC单标法、NH4C1单标法和HES双标法测定结果比实际值偏高。     

Evaluation of a new protocol for peripheral blood stem cell collection with the Fresenius AS 104 cell separator

In this report we analyzed sixty leukapheresis procedures on 35 patients with a new protocol for the Fresenius AS 104. Yields and efficiencies for MNC, CD 34+ cells, and CFU-GM indicate that the new protocol is able to collect large quantities of hemopoietic progenitors. Procedures were performed processing 8.69 ± 2.8 liters of whole blood per apheresis and modifying 3 parameters: spillover-volume 7 ml, buffy-coat volume 11.5 ml, centrifuge speed 1,500 rpm; blood flow rate was 50 ml/min and the anticoagulant ratio was 1:12. No side effects were observed during apheresis procedures except for transient paresthesia episodes promptly resolved with the administration of calcium gluconate. Yields show a high capacity of the new program to collect on average MNC 17.28 ± 10.85 × 10⁹, CD 34+ 471 ± 553.5 × 10⁶ and CFU-GM 1278.7 ± 1346.3 × 10⁴ per procedure. Separator collection efficiency on average was 49.91 ± 23.28% for MNC, 55.1 ± 35.66% for CFU-GM, and 62.97 ± 23.09% for CD 34+ cells. Particularly interesting are results for MNC yields and CD 34+ efficiency; these results make the new program advantageous or similar to the most progressive blood cell separators and capable to collect a sufficient number of progenitor cells for a graft with a mean of 1.80 ± 0.98 procedures per patient. J. Clin. Apheresis 12:82–86, 1997. © 1997 Wiley-Liss, Inc.     

Selective removal of sickle cells with the IBM 2997 continuous flow blood cell separator

Partial red cell exchange transfusion is used to manage several complications of sickle cell anemia. Reports have stressed the safety, case, and speed of red cell exchange procedures performed with blood cell separators, but little information exists concerning operating conditions for the most efficient removal of hemoglobin S (HbS) containing cells. We performed 13 red blood cell exchange transfusions with the IBM 2997 continuous flow blood cell separator on two previously transfused adult homozygous (SS) sickle cell patients. We used both a single stage and a dual stage disposable pathway and varied rotor speed, collection port, and collection interface independently. The patients' baseline percentage HbS ranged from 28 to 64% (mean = 46%); post exchange values ranged from 19.1 to 46% (mean = 32%). Thirty-three of 34 specimens collected from the white cell or platelet port showed a higher percentage of HbS in the collection line compared to simultaneous patient samples. Mean enrichment was 9.4% (range = ?4.0 to 35.5%). There was an inverse relationship between the hemoglobin concentration and the percentage of HbS in the collected specimens (p = 0.001; N = 45). Differential separation of sickle cells should decrease the volume of blood required for partial red cell exchange of selected SS patients.     

Assessment of stability of CD34+ cell products enriched by immunoselection from peripheral blood mononuclear cells during refrigerated storage

Durable engraftment of transplanted CD34+ cells largely depends on the quality of the cell product. Limited data are currently available about extended storage of immunoselected CD34+ cells. The aim of our study was to assess the stability of CD34+ cell product with the cells stored in high concentration (80 × 10⁶ in 6 mL) in small bags intended for cell implantation. Cell products were prepared by leukapheresis and immunoselection (Clinimacs^plus procedure) from 13 patients with chronic dilated cardiomyopathy. CD34+ cell products were stored at 2–8 °C and analyzed at time 0 (fresh products), 24, 48 h, 4 and 6 days. Product viability, absolute number of viable CD34+ cells and apoptosis were determined by flow cytometry. Microbiological contamination of the cell products was tested by BACTEC system. The mean viability of CD34+ cells decreased by 2.7% within 24 h, by 13.4% within 48 h and by 37.5% within 6 days. The mean recovery of viable CD34+ cells was 91.1%, 74.8%, 66.3% and 56.2% at 24, 48 h, 4 and 6 days, respectively. The mean fraction of early apoptotic cells in fresh and stored products was 4.9 ± 3.5% at 0 h, 5.9 ± 3.8% at 24 h, 4.2 ± 3.1% at 48 h, 6.3 ± 2.6% at 4 days and 9.3 ± 4.6% at 6 days. All products were negative for microbial contamination.     

人骨髓基质细胞协同外源性细胞因子对脐血CD34+细胞的体外扩增作用

目的　探讨人骨髓基质细胞 (hBMSC)协同以干细胞因子和FL为主的细胞因子对脐血CD3 4 + 细胞的体外扩增作用。方法　采用免疫磁珠法分选脐血CD3 4 + 细胞 ,以SCF +IL 3+IL 6 +FL +EPO组合高效扩增CD3 4 +细胞[1] ,并结合该细胞因子组合接种到预先照射 (2 0Gy)的hBMSC上 ,d10结束培养 ,收获细胞分别作细胞计数、集落培养和流式细胞术检测CD3 4 + 细胞数。结果　本法获得的脐血CD3 4 + 细胞纯度较高 (92± 0 .0 4 ) % ,在hBMSC组培养的d2 ,造血细胞几乎都粘附到hBMSC上 ,随着培养时间的延长 ,CD3 4 + 细胞比例不断下降。hBMSC组与无hBMSC组相比 ,除细胞总数扩增倍数外 ,CFU GM、BFU E、CD3 4 + 细胞扩增倍数差异有显著性意义 (P <0 .0 5 )。结论　①脐血来源的CD3 4 + 细胞粘附于滋养层上形成造血灶 ,且 10d后造血细胞仍具有体外集落形成能力 ,表明骨髓基质细胞可支持并维系体外造血 ;②hBMSC协同外源性细胞因子可能是扩增造血干 /祖细胞的较理想方案     

混合脐血血浆对脐血CD34^＋细胞体外扩增的作用

采用两步法分离出脐血CD34~ 细胞,比较研究了混合脐血血浆联合IL-3,IL-6,GM-CSF,Epo 4种中、晚期造血因子和单纯的4种造血因子情况下脐血CD34~ 细胞的体外扩增。结果表明,混合脐血血浆联合造血因子对粒-巨噬细胞集落形成单位(granulocyte-macrophage colony-forming unit,CFU-GM),红系爆式集落形成单位(burst-forming unit of erythriod,BFU-E),混合集落形成单位(minxed colony-forming unit,CFU-mix)3种集落的扩增效果明显优于单纯的4种造血因子联合组,差异具有统计学意义(P<0.01),但单纯混合脐血血浆扩增效果较差。脐血造血细胞扩增对子成人脐血移植有重要意义。上述结果提示,混合脐血血浆的扩增成功,可代替或弥补早期造血生长因子的作用,用于脐血造血细胞的体外扩增。     

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.     

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.     

Recommendations for optimized settings of the Amicus Crescendo cell separator for the collection of CD34+ progenitor cells

BACKGROUND: CD34+ PBPCs for autologous transplantation purposes are collected by leukapheresis procedures on automated cell separators. In this study, the influence of different parameters on collection efficiency (CE) of the Amicus Crescendo cell separator (Baxter) was investigated. STUDY DESIGN AND METHODS: A total of 146 PBPC collections with Amicus cell separators were performed in 56 patients with either settings recommended by the manufacturer or modified settings to identify variables that have a significant and important impact on CE. RESULTS: By use of a standard setting with a cycle volume of 1400 mL, CE significantly decreases when patients' preapheresis peripheral blood WBC counts are between 25,000 and 35,000 per micro L. CE can be improved if cycle volume is reduced to 1000 mL. If WBC concentrations exceed 55,000 per micro L before apheresis, CE also significantly decreases despite of reduced cycle volume. Additionally, high flow rates greater than 60 mL per minute significantly reduce CE. CONCLUSION: Parameters influencing the outcome of CD34+ PBPC collections were identified, such as patients' WBC count, cycle volume, and whole blood flow rate. An optimized adjustment of these variables will further increase the CE of the device.     

Enumeration of viable CD34+ cells in cord blood using a novel stem cell enumeration kit

ObjectiveTo assess the detection performance of the hematopoietic stem cell enumeration kit developed by BD Biosciences.MethodsCord blood samples were prepared using a hematopoietic stem cell enumeration kit developed by BD Biosciences and Stem-Kit reagents from Beckman Coulter. CD34+ cells were enumerated using a BD FACSCanto instrument and FACSDiva software.ResultsA total of 519 samples were analyzed in this study. The hematopoietic stem cell enumeration kit developed by BD Biosciences yielded absolute counts of CD34-positive cells that were on average 8.7% lower than Beckman Coulter Stem-Kit reagents (range: −5.7% to−14.7%). The BD Biosciences kit yielded relative counts that were on average 9.9% higher compared with Beckman Coulter Stem-Kit reagents (range: −2.1% to +13.8%). The intraclass correlation coefficients for absolute and relative counts of CD34-positive cells were 0.9967 (95% confidence interval [CI]: 0.9961–0.9972) and 0.9512 (95% CI: 0.9423–0.9587) for the BD Biosciences and Beckman Coulter kits, respectively.ConclusionsThe hematopoietic stem cell enumeration kit developed by BD Biosciences can be used to enumerate CD34-positive stem cells from cord blood samples.     

自体纯化CD34+细胞移植治疗自身免疫性疾病14例的临床观察

目的 探讨自体纯化CD34+细胞移植治疗自身免疫性疾病(AID)的疗效.方法 对14例自身免疫性疾病患者进行自体纯化CD34+细胞移植.采用环磷酰胺(CTX)+G-CSF动员外周血干细胞,通过CliniMACS细胞分选仪分选CD34+细胞并冻存.预处理方案:8例采用氟达拉滨(FDB)+抗胸腺细胞球蛋白(ATG)+CT...     

B淋巴细胞白血病骨髓B细胞CD34+CD38+和CD34+CD38low/-细胞亚群的临床意义

本研究比较发病时免疫表型为CD34+CD38+和CD34+CD38low/-两组B淋巴细胞白血病(B-ALL)的生物学特性,并探讨其临床意义。选取54例初发B-ALL并经多参数流式细胞术检测为CD34+的B-ALL患者,根据CD38表达不同将其分为CD34+CD38+组(n=35)和CD34+CD38low/-组(n=19)。利用实时定量PCR的方法分别进行BCR-ABL,TEL-AML1和WT1基因的检测。随访标本利用7色流式细胞术检测微量残留病(MRD),平均随访时间12个月(1-28个月),平均随访间隔2个月(1-5个月)。结果表明,两组患者发病时WBC,血小板和血红蛋白水平及BCR-ABL,TEL-AML1和WT1基因阳性表达的比例均无统计学差异(P>0.05)。在诱导缓解后,CD34+CD38+组微量残留病阳性(MRD+)为28.57%(10/35),CD38low/-组MRD+为68.42%(13/19),CD34+CD38low/-组MRD+的检出率明显高于CD34+CD38+组(P<0.01)。在复发率上,CD34+CD38+组有2例,分别在第94天和第245天复发,复发率为5.71%(2/35)。CD34+CD38low/-组有7例复发,复发率为36.84%(7/19),中位复发时间263 d(46-468 d),两组间具有明显统计学差异(P<0.01)。本研究以16岁为年龄分界点,CD34+CD38+组16岁以上患者为8人(8/35),CD34+CD38low/-组16岁以上患者为10人(10/19),两组间有统计学差异(P<0.05)。结论:CD34+CD38low/-患者在成人中比例较高,且CD34+CD38low/-组在治疗后更易出现MRD+和复发。     

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.