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.     

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.     

Implementation of peripheral blood CD34 analyses to initiate leukapheresis: marked reduction in resource utilization

BACKGROUND: Analysis of the peripheral blood (PB) C34 value may determine the optimal time to initiate leukapheresis. STUDY DESIGN AND METHODS: After selecting a threshold PB CD34 value of five CD34 + cells per microL to initiate leukapheresis procedure, a prospective analysis of 50 consecutive patients was initiated to identify the optimal time to initiate leukapheresis and its impact on costs and resource utilization. Clinical decisions were made to commence or to postpone leukapheresis with this PB CD34 threshold number. Based on PB CD34 values for each patient, the number of leukapheresis procedures, postponed or canceled, the number of CD34+ cells per kg, and the total number of cells collected were identified. Costs of mobilization were obtained from the hospital cost accounting system. RESULTS: In 13 months, 50 patients with a hematologic disorder underwent mobilization. There were 34 cancellations or postponements of collections due to a low PB CD34 value in 13 patients. By use of our identified costs per initial collection, this resulted in a savings of 67,660 US dollars. CONCLUSIONS: This prospective study defines how the implementation of the PB CD34 value results in costs savings. A low PB CD34 value canceled or postponed a significant number of leukapheresis procedures, resulting in a substantial cost savings. Use of the PB CD34 value should be the standard of care during mobilization and peripheral blood progenitor cell collection.     

The absolute number of circulating CD34+ cells as the best predictor of peripheral hematopoietic stem cell yield.

Many controversies still exist about the timing of leukapheresis procedures for PBSC transplantation. Thirty-nine patients were followed daily by monitoring the absolute PB WBC count and CD34+ cell enumeration prior to apheresis. These determinations were compared with the apheresis cell content (nucleated cells and CD34+ cells yield). There was a highly significant correlation between PB CD34+ cells and apheresis CD34+ cell yield (r = 0.921, p < 0.001). A small but significant correlation was found between the PB WBC count and the apheresis nucleated cell content (r = 0.383, p < 0.001), but no correlation was found between PB WBC count and apheresis CD34+ cell yield (r = -0.065, p = 0.460). A target value of 20 x 10(6) CD34+ cells/L was determined to be the most reliable predictor to collect at least 1.0 x 10(6) CD34+ cells/kg in a single apheresis. Of the 39 patients, 20 could be followed after transplantation, and a good correlation was found for total number of CD34+ cells reinfused and platelet and neutrophil engraftment. No correlation was found for nucleated cells infused and engraftment. CD34+ cell determination is a better predictor than WBC count for timing leukapheresis and is thus recommended for monitoring the quality of the product.     

Mobilization kinetics of CD133+ hematoprogenitor cells for hematopoietic grafting

BACKGROUND: Quantification of CD34+ mononuclear cells is the most important quality control measure for hematopoietic stem cell (HSC) transplantation. A fraction of CD34+ cells also express the CD133 antigen. These cells constitute a group of earlier, less-differentiated HSCs with a potentially higher capacity for engraftment. The correlation between total CD34+ peripheral HSCs and the fraction of these cells that coexpress CD133 was determined before and after automated collection by leukapheresis, as well as the effect of HSC CD133+ dose on hematopoiesis recovery.
STUDY DESIGN AND METHODS: Granulocyte–colony-stimulating factor mobilization of HSCs from the marrow to the peripheral blood (PB) of allogeneic and autologous donors was followed by automated collection through leukapheresis on the fifth day. Quantification of CD34+ and CD133+ cells was performed on PB before collection and in the hematopoietic graft (HG) by flow cytometry.
RESULTS: There was a significant correlation between CD133+ and CD34+ HSCs in the PB before collection and in the final product for grafting (r = 0.62 and 0.64; p < 0.01). CD34+ HSCs per µL in PB and the HG was the only variable that did not correlate (r = 0.18). CD34+/CD133+ correlation increased from 0.33 on PB to 0.94 on the leukapheresis product (p < 0.01). Time to recovery was not related to CD133+ HSCs infused.
CONCLUSION: There was a significant correlation of both number per µL and percentage of CD34+/CD133+ HSCs before and after collection for transplantation; number of CD133+ cells had no apparent clinical impact on time to hematopoiesis regeneration.     

PBPC collection techniques: standard versus large volume leukapheresis (LVL) in donors and in patients.

Transplantations of autologous and allogeneic peripheral blood progenitor cells (PBPC) are able to assure a complete hematopoietic and immunologic reconstitution in patients. PBPC are collected by leukapheresis technique after prior mobilization therapy, but procedures and results remain still highly variable and are poorly characterized. An optimum regimen for PBPC collections has not yet been recommended, but 2-3 total blood volumes (TBV) of the donor or patient are regarded as a standard. Another promising technique is large volume leukapheresis (LVL) with processing of 3-6 TBV of donor or patient. The aim of this paper is to find the most efficient and safe collection technique for an individual donor or patient and, consequently minimize the number of procedures required. Finding the optimal collection procedure would be helpful while considering which method would be preferred in an individual donor or patient with respect to the result of mobilization, health state and required yield of CD 34+ cells for transplantation. We evaluated the results in a total of 134 standard and LVL procedures, which were performed in 21 well mobilized donors (Group I), in 65 well mobilized patients (Group II), and in 14 weakly mobilized patients (Group III) with hemato-oncological diseases. A precollection concentration of CD 34+ cells in peripheral blood higher than 20 x 10(3)/mL was considered to be the criterion for efficient mobilization. Such levels of concentration indicating the start of PBPC collections could be easily reached in Group I of donors and Group II of well mobilized patients. Heavily pretreated patients at advanced stages of disease (Group III) did not respond to mobilization sufficiently and had a concentration of CD 34+ cells lower than 20x10(3)/mL. LVL technique made it possible to obtain higher numbers of CD 34+ cells than in the standard collection in well mobilized donors (Group I), well mobilized patients (Group II), and even in weakly mobilized patients in Group III. In donors and well mobilized patients (Group I and Group II) it was possible to collect sufficient amounts of CD 34+ cells for allogeneic or for autologous transplantation from one LVL collection. The median yield of CD 34+ cells from one LVL collection was 5.5 x 10(6)/kg b.w. in donors, and 6.0 x 10(6)/kg b.w. in well mobilized patients. Due to the linear dependence of the yield of collected CD 34+ cells on the concentration of CD 34+ cells in blood, it can be used as a simple prediction of the success of collection in Group II (correlation coefficient 0.93 for standard procedures, and correlation coefficient 0.88 for LVL). In Group III of weakly mobilized patients the standard collections were usually ineffective and the relationship between the yield of CD 34+ cells/kg in the product and the precollection concentration of CD 34+ cells was much less significant (correlation coefficient 0.56 for standard procedures and correlation coefficient 0.66 for LVL). The median of CD 34+ cells collected from one standard procedure was only 0.7 x 10(6)/kg but using LVL the median increased to 1.4 x 10(6)/kg. Our results prove that the yield of CD 34+ cells in the product can be enhanced by large volume leukapheresis (LVL). Based on the results obtained, we recommend LVL in all donors and patients who can tolerate it due to a greater chance of collecting higher yields of progenitor cells while minimizing adverse reactions. LVL procedures should also be preferred in weakly mobilized patients where it is not possible to collect sufficient amounts of CD 34+ cells for transplantation using the standard regime. In weakly mobilized patients LVL provides a greater chance to at least collect a minimum amount of CD 34+ cells necessary. LVL should be used in circumstances where extremely high doses of CD 34+ cells has to be prepared, e.g. planned "tandem" transplantations or manipulations with a graft in which a significant loss of cells is expected.     

自体外周血单个核细胞移植治疗下肢动脉缺血性疾病的研究

目的 分析59例下肢缺血性疾病患者进行自体外周血单个核细胞(MNC)移植的疗效及其与移植MNC数及CD34+细胞数的相关性,探索外周血MNC在下肢动脉缺血性疾病治疗中的优势.方法 对59例患者治疗前静息痛、冷感、间歇性跛行及组织损伤分别进行评分,而后动员并采集自体外周血MNC,于缺血下肢多位点等间距注射.评价治疗后第7天及4个月时的治疗效果,分析注入的MNC数及其中所含CD34+细胞数与疗效的相关性.结果 MNC移植后第7天及4个月时患者的下肢缺血均有不同程度的改善,CD34+细胞数量与疗效的相关系数为0.461(P=0.047),尼莫地平值=0.484+1.055×CD34+细胞数,MNC数量与疗效的相关系数为0.473(P=0.000),尼莫地平值=0.288+0.401×MNC数.结果 显示MNC数量比CD34+细胞数量与疗效的相关性更强.结论 注入的自体外周血MNC数较CD34+细胞数更能反映与临床疗效的相关性.

Abstract：

Objective To analyze the efficacy and its correlation with species of transplant cells of autologous mobilized peripheral blood(PB) mononucleated cells (MNCs) transplantation on 59 patients with lower limbs ischemia. Methods Fifty-nine patients were evaluated with symptoms scores and after that their PBMNCs were mobilized and collected and then injected into the ischemic area at equal distance. They effectiveness and scores were evaluated at 7th day and 4th month after therapy. The correlation of CD34 + cells and of MNCs with effectiveness was analysed respectively, and formula for c orrelations between them and effectiveness was calculated. Results After MNCs injection, the effectiveness was observed both at 7th day and 4th month . The correlation of MNCs with effectiveness was stronger than that of CD34 + cells ( the effectiveness was represented by nimodipine value), According to the formula of nimodipine value, the value of the latter =0.484 + 1. 055 × CD34 + cells number and the former = 0.288 + 0. 401 × MNCs number with a correlation coefficient of R =0. 461( P =0. 047 ) and R =0. 473 ( P =0. 000 ) respectively. Conclusion Autologous mobilized PBMNCs number is a better indicator for effectiveness than CD34 + cells number.     

Peripheral blood stem cell collection: the interaction of technology, procedure, and biological factors

Centrifugal technology, continuous flow and discontinuous flow, has served as the technology platform for extracting cell concentrates of interest from peripheral blood (PB) for patient therapy for the past 35-40 yr. Models for procedure outcome exist for collection of normal donor (ND) platelet and granulocyte concentrates that integrate: (1) biological variables (pre-procedure PB cell concentration, the total circulating quantity of cells, donor/patient blood volume (BV)), (2) device efficiency, and (3) procedure parameters such as total blood processed (TBP), and in the case of cytoreductions - the volume collected. (cf. Hester J, Kellogg R, Mulzet A, et al., Blood (54) (1979) 254; Hester J, Ventura G, J Clin Apheresis (4) (1988) 188.) To date, no predictive CD34+ yield algorithm integrating these three variables has been formulated that could be applied prospectively for individual ND or patients (PT). There are economic, toxicity and statistical comparison benefits to be derived from generating such an algorithm.A small pilot study is presented with a brief review of current publications that suggest the circulating quantity of CD34+ cells available to be collected and the quantity mobilized during leukapheresis are the major contributing factors to CD34+ yield, somewhat obscuring the role of the total blood processed (TBP). Intraprocedure CD34+ cell mobilization, incompletely characterized to date, appears to be a dynamic nonlinear process, as the harvested yield does not rise proportionally as the fraction of BV processed increases. And, like the pre-procedure PB CD34+ concentration and total circulating quantity, CD34+ mobilization during leukapheresis probably relates to prior treatment and the priming regimen. Studies that provide: (1) separate analyses of PT populations divided according to chemotherapy toxicity factors; (2) design and implementation of optimal priming regimens with respect to dose 'intensity' of both growth factors and chemotherapy; and (3) standardization of laboratory assays of CD34+ enumeration seem essential to generating a predictive algorithm.     

The relation between the number of PBSC and number of leukaphereses in children.

Although PBSC transplantation has an advantage over BM transplantation in that fewer burdens are placed on the patient at the time of stem cell collection, the number of collected cells decreases when leukapheresis is done repeatedly. We examined the relation between the number of times leukapheresis is performed and the number of mononuclear cells (MNC), CD34+ cells, and colony-forming unit-granulocyte-macrophages (CFU-GM) collected. The percentage of CD34+ cells was measured by flow cytometry and the number of CFU-GM was measured by a progenitor assay. The number of cells collected was significantly decreased by the third collection. Therefore, to secure enough cells for transplantation, leukapheresis ideally should be performed no more than twice if PBSC collection is to be efficient.     

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.     

Peripheral blood circulating immature cell counts predict CD34+ cell yields in G-CSF-induced PBPC mobilization in healthy donors

BACKGROUND: It has been previously reported that the number of circulating immature cells (CIC) in peripheral blood (PB) estimates the number of CD34+ cells collected in G-CSF plus chemotherapy-induced PBPC mobilization. The correlation of CIC counts in PB with CD34+ cell yield and its usefulness was evaluated in G-CSF-induced PBPC mobilization for healthy donors. STUDY DESIGN AND METHODS: CIC counts in PB and CD34+ cell counts in the apheresis product from 122 collections were assessed, and the relationship between these two variables was evaluated with the Pearson rank correlation analysis, the chi-squared test, and the U-test. RESULTS: CIC counts were correlated weakly with the number of CD34+ cells per L of blood processed in the apheresis product (Pearson rank correlation analysis; r=0.357, p<0.0001). When a level of 1.7 x 10(9) CICs per L was selected as a cutoff value, the sensitivity and specificity for collecting more than 20 x 10(6) CD34+ cells per L of blood processed were 63.6 and 77.5 percent, respectively. CONCLUSION: The present study suggests that the number of CICs in PB may estimate the number of CD34+ cells collected. The data indicate that CIC counts above 1.7 x 10(9) per L can be used as a good predictor for PBPC collections containing more than 20 x 10(6) CD34+ cells per L of blood processed in a single apheresis procedure.     

CD34+ cells and CD34+CD38- subset from mobilized blood show different patterns of adhesion molecules compared to those from steady-state blood, bone marrow, and cord blood

As suggested previously, a down-regulation of some cellular adhesion molecules (CAMs) on CD34(+) hematopoietic progenitor cells (HPC) may contribute to their egress from bone marrow (BM) to peripheral blood (PB) by decreasing their adhesion to BM stromal cells. Besides counting the percentage of CAM-positive cells, we decided to define clearly the antigen density (AgD) of the CAM on mobilized- and steady-state CD34(+) HPC using QIFIKIT calibration beads. Five sources of cells were compared: PB and BM from normal donors (nPB, nBM) cord blood (CB), mobilized PB obtained from leukapheresis products (LKP), and mobilized BM (mBM) samples. In our study the CAM-AgD was the lowest on CD34(+) cells in LKP which, on the contrary, contained the highest percentage of CD117(+), CD54(+), CD58(+) cell subsets. As for CB, a greater proportion of CD44(+) and CD62L(+) cells was observed in LKP than in other products. The LKP-CD34(+) cell population contained a greater percentage of CD11a(+) cells when compared to mBM, but the lowest percentage of CD49d(+) and CD49e(+) cells when compared to all products. The proportion of the CD34(+)CD38(-) immature subset expressing CD11a, CD44, CD54, or CD62L was greater in LKP than in mBM; the CD62L-AgD was higher in LKP than in mBM. This quantitative analysis clearly showed a downregulation of all CAM on LKP-CD34(+). The CD44, CD62L, CD11a, and CD54 AgD decrease appears to be specifically involved in the egress of the CD34(+) subsets into PB. The control of antigen density of these adhesion molecules is likely to be clinically important for effective mobilization of HPC as well as for rapid engraftment following HPC transplant.     

Predictive value of circulating immature cell counts in peripheral blood for timing of peripheral blood progenitor cell collection after G-CSF plus chemotherapy-induced mobilization

BACKGROUND: Enumeration of CD34+ cells in peripheral blood (PB) before apheresis predicts the number of CD34+ cells collected, although flow cytometric techniques used are complex and expensive. In an attempt to determine the optimal timing for peripheral blood progenitor cell (PBPC) collection, the usefulness of circulating immature cell (CIC) counts in PB was evaluated. STUDY DESIGN AND METHODS: CIC counts in PB and CD34+ cell counts in the apheresis product from 249 collections were assessed, and the relationship between these two parameters was evaluated by with the Pearson rank correlation analysis, the Fisher exact test, and the U-test. RESULTS: CIC counts were correlated significantly with the number of CD34+ cells per kg of patient's body weight in the apheresis product (Pearson rank correlation analysis: r = 0.635, p < 0.0001). When a level of 1 x 10(9) CICs per L was selected as a cutoff value, the sensitivity and specificity for collecting more than 1 x 10(6) CD34+ cells per kg of body weight were 75.7 and 85.5 percent, respectively. CONCLUSION: The present study strongly suggests that the number of CICs in PB may estimate the number of CD34+ cells collected. The data indicate that CIC counts above 1 x 10(9) per L can be used as a good predictor for PBPC collections containing more than 1 x 10(6) CD34+ cells per kg of body weight in a single apheresis procedure.     

Decreased stroma adhesion capacity of CD34+ progenitor cells from mobilized peripheral blood is not lineage- or stage-specific and is associated with low beta 1 and beta 2 integrin expression

Molecular mechanisms leading to mobilization of hematopoietic cells from bone marrow (BM) to peripheral blood (PB) involve modulation of adhesion molecule expression on these cells that probably result in changes in adhesion capacity to the microenvironment. However, it is not clear whether these changes involve different stages or lineages of progenitor cells. In this study, we compared the capacity of mature and immature clonogenic progenitor cells from granulocyte colony-stimulating factor (G-CSF)-mobilized PB and normal BM CD34+ cells to adhere to complete marrow stroma. This functional capacity was assessed concurrently with molecular expression on CD34+ cells of integrins VLA-4 (alpha 4/beta 1), VLA-5 (alpha 5/beta 1), and LFA-1 (alpha L/beta 2) by interindividual (between mobilized PB and normal BM) and intraindividual (between mobilized PB and steady-state BM and PB in the same patient) analysis. The proportion of adherent clonogenic progenitor cells was significantly lower in PB than in BM, not only for total progenitor cells but also for mature and immature progenitor cells, and the difference was found for granulocytic and particularly for erythroid lineages. The lower adhesion capacity of PB CD34+ cells to stroma was associated with decreased expression (signal/noise MFI ratio) of integrin alpha 4, beta 1, alpha L, and beta 2 chains whereas that of alpha 5 chain did not differ from BM cells with the lowest expression level. Similar differences in integrin expression levels were also found between mobilized PB and steady-state BM CD34+ cells in the same patient except for the alpha L chain. Moreover, we demonstrated for the first time a strong positive correlation between mobilizing capacity and expression levels on mobilized CD34+ cells for the LFA-1 alpha L chain but not for VLA-4 or VLA-5. In conclusion, the decreased adhesion capacity of mobilized PB progenitor cells to stroma involves different maturation stages and different lineages. This is associated with down-regulation of integrins VLA-4 and LFA-1, but mobilizing capacity appears positively correlated with LFA-1 levels.     

Clinical impact of a new automated system employed for peripheral blood stem cell collection

At the moment, PBSC collections can be performed using semi-automated or automated cell separator devices. The automated methods offer the advantages of a decreased working load for dedicated personnel and high standardization of the collection procedure. Herein we report our single institutional experience in 80 PBSC collections employing the new automated COM.TEC Fresenius autoMNC program that provides the ability to predict the total number of CD34(+) cells collected, based on the pre-leukapheresis CD34(+) cell count in peripheral blood. Fourty-eight patients and 21 healthy donors were mobilized with chemotherapy + G-CSF or G-CSF alone, respectively. Eighty leukapheresis collections were performed starting with a CD34(+) cell count in peripheral blood at least of 20/microL. Collection parameters and related side effects were evaluated. The mean CD34(+) cell collection efficiency in patients and donors was 81.8% (sd 27.6) and 95.1% (sd 15.6), respectively. The mean difference between real and predicted CD34(+) cells was +30.2% (sd 92.9) for patients and +4.6% (sd 30.3) for donors. The mean leukapheresis bag volume was 240.7 ml (sd 67.3) and 310.3 ml (sd 86.8) with a mean HCT of 10.9% (sd 34.4) and 9.2% (sd 3.9) for patients and donors, respectively. The automated PBSC collection with the new program COM.TEC Fresenius autoMNC demonstrated a very high CD34(+) cell collection efficiency. Moreover, the ability to predict the CD34(+) cell yield permits improved management of the leukapheresis collection, with the only disadvantage of larger leukapheresis volume and higher hematocrit.     

Monitoring of peripheral blood CD34+ cell counts on the first day of apheresis is highly predictive for efficient CD34+ cell yield.

The purpose of this study was to evaluate the correlation of preleukapheresis circulating CD 34+ cells/micro L, white blood cells (WBC), and platelet counts on the first day of apheresis with the yield of collected CD 34+ cell counts in 40 patients with hematological malignancies (n = 29) and solid tumors (n = 11). The median numbers of apheresis cycles, numbers of CD 34+ cells, peripheral blood (PB) mononuclear cells, and total nucleated cells collected were 2 (range, 1-4), 5.5 x 106/kg (range, 0.05-33.78), 2.59 x 108/kg (range, 0.04-20.68), and 7.36 x 108/kg (range, 0.15-28.08), respectively. There was a strong correlation between the number of preleukapheresis circulating CD 34+ cells/micro L and the yield of collected CD 34+ cells per kilogram (r = 0.962, p < 0.001). The threshold levels of PB C 34+ cell/micro L to obtain > or =1 x 106/kg and > or =2.5 x 106/kg CD 34+ cell in one collection were 12/micro L and 34/ micro L, respectively. Fifteen of 17 (88%) patients who had > or =34 CD 34+ cells/ micro L in the PB before collection reached the level of > or =2.5 x 106/kg in a single apheresis. Despite a low r value, WBC and platelet counts on the first day of apheresis also correlated with the yield of collected daily CD 34+ cells per kilogram (r = 0.482, p < 0.01 and r = 0.496 p < 0.01, respectively). These data suggest that preleukapheresis circulating CD 34+ cells/ micro L correlated significantly better with the yield of collected CD 34+ cells than WBC and platelet counts on the first day of apheresis. Using a value of 34/micro L preleukapheresis circulating CD 34+ cells as a guide for the timing of peripheral blood stem cells collections can be time saving and cost-effective.     

Leukapheresis after high-dose chemotherapy and autologous peripheral blood progenitor cell transplantation: a novel approach to harvest a second autograft

BACKGROUND: Autologous peripheral blood progenitor cells (PBPCs) are usually collected after the administration of conventional-dose chemotherapy (CDCT) and growth factors. However, there are no data available concerning the collection of PBPCs after high-dose chemotherapy (HDCT) and autologous hematopoietic transplantation in a larger series. STUDY DESIGN AND METHODS: Patients (n = 30) underwent leukapheresis for PBPC harvest after CDCT. After HDCT and autografting, the collection of a second PBPC autograft was attempted. RESULTS: Leukapheresis was performed after CDCT in all cases at a median of 118 CD34+ cells per microL (range, 18-589) and resulted in 6.4 x 10(6) CD34+ cells per kg (range, 1.7-29.0). After HDCT and autografting, 24 patients (80%) underwent secondary leukapheresis, although they had a significantly lower median of peripheral blood (PB) CD34+ cells (30/microL; range, 10-171; p < 0.001). In these patients a median of 3.6 x 10(6) CD34+ cells per kg (range, 1.6-10.1) was collected in the post-transplantation course. In the remaining six patients (20%) with PB CD34+ cells < 10 per microL, no PBPC harvesting was performed. These so-called poor mobilizers had received significantly less CD34+ cells for autologous transplantation than patients with successful post-HDCT mobilization (median, 2.5 x 10(6)/kg [range, 1.7-3.0] vs. 6.5 x 10(6)/kg [range, 3.2-19.6]; p < 0.001). CONCLUSION: Collection of PBPCs is possible in most patients during the recovery phase of hematopoiesis after HDCT plus autografting, and the number of circulating PBPCs may be related to the CD34+ cell dose transfused by the preceding autograft.     

Augmented mobilization and collection of CD34+ hematopoietic cells from normal human volunteers stimulated with granulocyte-colony-stimulating factor by single-dose administration of AMD3100, a CXCR4 antagonist

BACKGROUND: AMD3100, a selective antagonist of CXCR4, rapidly mobilizes CD34+ hematopoietic progenitor cells (HPCs) from marrow to peripheral blood with minimal side effects. STUDY DESIGN AND METHODS: To further investigate potential clinical utility of AMD3100 for CD34+ cell mobilization and collection, a Phase I study in normal volunteers was performed examining single-dose administration of AMD3100 alone and in combination with a standard 5-day granulocyte-colony-stimulating factor (G-CSF) regimen. RESULTS: AMD3100 (160 microg/kg x 1 on Day 5) significantly increased both G-CSF-stimulated (10 microg/kg/day) mobilization of CD34+ cells (3.8-fold) and leukapheresis yield of CD34+ cells. Moreover, collection of CD34+ cells was comparable between individuals mobilized by a single-dose regimen of AMD3100 (240 microg/kg) and individuals mobilized with a 5-day regimen of G-CSF. AMD3100-mobilized leukapheresis products contained significantly greater numbers of T and B cells compared to G-CSF-stimulated leukapheresis products. CONCLUSION: These findings indicate that AMD3100 can be used alone or as an adjunct to G-CSF to mobilize cells for HPC transplantation.     

Kinetics of peripheral blood stem cell harvests during a single apheresis

BACKGROUND: The enumeration of CD34+ cells in the peripheral blood of patients before leukapheresis is commonly used to predict the outcome of stem cell harvests. The concept that an increased number of transplanted cells gives faster marrow reconstitution triggers an interest in investigating the kinetics of peripheral blood stem cells during leukapheresis. The aim of this study was to investigate the issue of recruitment of hematopoietic progenitor cells during a single leukapheresis. STUDY DESIGN AND METHODS: Nine leukapheresis procedures (in 8 patients) were investigated. In each case, 3 blood volumes were processed. Samples from peripheral blood, the collection line of apheresis equipment, and the collected component were obtained after each blood volume was processed. The enumeration of CD34+ cells was performed, and the total number of progenitors, as a sum of the number of cells in the peripheral blood and the number of cells in the collected component, was calculated. RESULTS: A mean of 13.3 L of blood was processed, and a component with a mean volume of 424 mL and a mean of 10.1 x 10(6) CD34+ cells per kg of body weight was collected. White cell and mononuclear cell counts in peripheral blood declined concomitantly during the procedures. The calculated total number of cells--that is, the sum of the number of cells in the collected component and the number of cells in the peripheral blood--showed a concomitant, but not equal, rise in polymorphonuclear cells, mononuclear cells, and CD34+ cells during the leukapheresis. This apparent mobilization of progenitors into the peripheral blood did not correlate with the slightly increased number of polymorphonuclear cells or with the more pronounced increase in mononuclear cells. CONCLUSION: There is a substantial recruitment of progenitor cells during a single leukapheresis.