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.     

Direct volumetric flow cytometric quantitation of CD34+ stem and progenitor cells

Objectives: In this study, we compared a classic single‐platform (SP) method applying beads for enumeration of CD45+ or CD34+ cells with a new device allowing direct volumetric measurements of stem and progenitor cells. Background: Following apheresis and cyropreservation, the precise enumeration of CD34+ cells as key parameter of graft quality is mandatory for the clinical course after transplantation. Currently, flow cytometry with SP technique represents the ‘gold standard’ for such determinations. Methods/Materials: Fresh samples, 14 from mobilised peripheral blood (PB), 9 from apheresis products (AP) and 13 samples from frozen‐thawed (FT) haematopoietic progenitor cell grafts, were analysed for CD34+ cells, CD45+ cells, and in frozen‐thawed samples for viability by a bead‐based flow cytometric method and in parallel by a direct, volumetric flow cytometric method. Results: Comparison of CD34+ analyses revealed a significant correlation (P < 0·01) for each material between both techniques with r = 0·95 (PB), r = 0·933 (AP) and r = 0·929 (FT). Also, for analysis of CD45+ cells µL^?1, the measured numbers evaluated with the different techniques did not significantly differ for all three materials analysed. In frozen‐thawed samples, the analysis of viability was comparable for both techniques. Conclusions: The results of this study demonstrate that a direct volumetric analysis of CD34+ cells µL^?1 or CD45+ cells µL^?1 is feasible. This technique represents a simple and economical approach for standardisation of progenitor and stem cell analyses.     

流式细胞术计数CD34阳性细胞的标准化与质量控制

用流式细胞术计数脐带血,外周血及其采集物中的ＣＤ３４＾＋细胞数已被普遍采用,然而,不同实验之间的ＣＤ３４＾＋细胞计数差异非常大,本就影响结果的主要因素,目前国际上采用的标准化方案和不同方案之间的比较进行综述,我们实验室应用ＰｒｏＣＯＵＮＴ试剂盒检测了４５例脐带血,１２份正常骨髓和４例外周血采集物中的ＣＤ３４＾＋细胞的数量,结果表明ＰｒｏＣＯＵＮＴ为标准化程度较高的方法,有利于减少不同实验之间ＣＤ３４＾＋细胞计数的差异。     

Evaluation of the Sysmex XN automated hematopoietic progenitor cell enumeration for timing of peripheral blood stem cell harvest

BackgroundEnumeration of stem cells is essential in the management of peripheral blood stem cell (PBSC) harvest. An alternative to the gold standard flow cytometric CD34+ stem cell count is the fully automated hematopoietic stem cell (HPC) count on the Sysmex XN hematology analyzer.Materials and methodsEighty-nine patients and healthy stem cell donors who underwent PBSC harvest were included in the study. Stem cells were enumerated in pre-harvest peripheral blood and the apheresis yield by both flow cytometric CD34+ stem cell enumeration and by the Sysmex XN HPC count.ResultsThe Sysmex HPC concentration overestimated the CD34+ stem cell concentration by a ratio of 1.3 in average. The agreement between the two methods was poor at concentration <40 stem cells/μL (Bias: 45 %, 95 % limits of agreement: -71 - 160 %). CD34+ stem cell concentration and HPC concentration correlated well in pre-harvest peripheral blood (R=0.73, slope=0.96). We established a positive cut off >43.5 HPC/μL, where PBSC harvest can be initiated. And a negative cut off <16.5 HPC/μL, where harvest should be postponed or other mobilizing regimens or bone marrow harvest should be considered. 33 % of measurements were in between the negative and positive cut-off and would require a supplementary CD34+ cell count.ConclusionAlthough Sysmex HPC count correlates well with CD34+ cell count in peripheral blood, the agreement between the two methods is poor, especially at low concentrations, namely in the clinical decision range. Sysmex HPC count as a surrogate for CD34+ cell count should, therefore, be used with caution.     

An alternative test for determining autologous stem cell transplantation cell harvesting outcome: Comparison between predictive values of two tests

Daily CD34+ cells enumeration as a success indicator of stem cell pheresis procedure using flow cytometry is costly, lengthy, and labor-intensive. Thus, finding a simpler method to achieve the optimum time for harvesting the minimum required stem cells for transplantation could be helpful. The aim of this study was to evaluate the predictive value of reticulocytes fractions and their sensesivity and specificity in guiding CD34+ cell harvesting by G-CSF mobilization strategy. In this study, 49 candidates for autologous peripheral blood stem cell transplantation were enrolled. Before leukapheresis, the immature reticulocytes fraction (IRF) and CD34+ cell count were measured. Moreover, patients were evaluated for leukapheresis outcomes in two MNC and cMNC groups. Here we demonstrated that IRF, LFR, and MFR with the associated criterion of >17.3, ≤82.5, and >15.9, respectively, earned 100 % specificity and 47.2 %, 47.22 %, and 41.46 % sensitivity to predict the minimum required CD34+ cell count. Furthermore, IRF-V (Value) and MFR-V with the associated criterion of >0.77 and >0.55, respectively, earned 58.33 %, 66.67 % sensitivity and 84.62 %, 69.23 % of specificity, separately. As only MFR-V was able to predict the platelet engraftment (P-value = 0.014), none of the other above mentioned factors were not able to predict the neutrophil engraftment. Likewise, it was shown that patients who underwent MNC leukapheresis had a statistically significantly higher total WBC, harvested CD34⁺ cells, MNCs/ kg, and lower apheresis durations (P-values<0.05). Taken together, using IRF and its maturity stages seems to be a compelling predictor of minimal required CD34+ cells in autologous peripheral blood stem cell transplantation.     

Comparison of three single platform methods for CD34+ hematopoietic stem cell enumeration by flow cytometry

In the present study, we compared three single platform methods for CD34+ hematopoietic stem cell (HSC) enumeration by flow cytometry. For this purpose, we analyzed the performance characteristics and results obtained from different HSC sources. Interlaboratory coefficients of variation (CV) for precision/reproducibility analysis varied from 4.0% to 6.7% / 6.7% to 9.2% for the low and 3.2% to 4.1% / 4.3% to 6.7%, respectively, for the high stem cell control. Correlation between methods ranged from 0.92% to 0.99%; Wilcoxon test showed no significant differences (p > 0.05); Bland-Altman analysis confirmed good agreement between assays (mean bias ranging from -0.48 to 6.91). Our results demonstrate very good intralaboratory correlation and agreement between methods, confirm the major impact of single platform strategy for accurate and reproducible HSC enumeration and suggest that high interlaboratory variability could be influenced by incorrect performance of validated methods.     

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.     

短程大剂量粒细胞集落刺激因子动员外周血造血干细胞的研究

研究短程大剂量粒细胞集落刺激因子对外周血造血干细胞的动员作用。方法采用短程大剂量Ｇ－ＣＳＦ对１１例患者进行外周血造血干细胞动员，Ｇ－ＣＳＦ５μｇ／ｋｇ皮下注射，每日２次，共３天，动员当天及第４天，分别取骨髓及外周血增生明显活跃，外周血白细胞计数明显升高。     

Flow cytometric CD34+ stem cell enumeration: lessons from nine years' external quality assessment within the Benelux countries

BACKGROUND: A biannual external quality assurance (EQA) scheme for flow cytometric CD34+ haematopoietic stem cell enumeration has been operational in the Benelux countries since 1996. In an evaluation of the results of 16 send-outs, we studied the effects of the methods used on assay outcome and whether or not this exercise was effective in reducing between-laboratory variation. METHODS: Data were analyzed using robust multivariate regression. This approach is relatively insensitive to outliers and is used to assess the effect of methodological aspects of CD34+ cell counting on the bias and variability. RESULTS: Five variables were associated with significant bias of absolute CD34+ cell counts: (i) unique laboratory number (ULN), (ii) gating strategy; (iii) CD34 mAb fluorochrome; (iv) type of flow cytometer, and (v) method of sample preparation. In addition, ULN and platform methodology (i.e., single vs. dual) contributed significantly to the variability of this assay. Overall, the variability in results of CD34+ cell enumeration has declined with time; in particular, after a practical workshop in which participants were trained to use the "single platform ISHAGE protocol." CONCLUSIONS: Between-laboratory variation in CD34+ cell enumeration can be reduced by standardization of methodologies between centres. Our approach, i.e., EQA with targeted training and feedback in response to reported results, has been successful in reducing the variability of CD34+ cell enumeration between participants.     

Preharvest hematopoietic progenitor cell counts predict CD34+ cell yields in granulocyte–colony‐stimulating factor–mobilized peripheral blood stem cell harvest in healthy donors

BACKGROUND: The hematopoietic progenitor cell (HPC) count measured by the Sysmex hematology analyzer can determine the timing for leukapheresis in autologous peripheral blood stem cell (PBSC) harvest. We evaluated whether a HPC count could predict CD34+ cell yield in healthy, unrelated donors after granulocyte–colony‐stimulating factor mobilization. STUDY DESIGN AND METHODS: A total of 117 healthy donors underwent 161 PBSC leukapheresis procedures in our institution. The HPCs and CD34+ cells were identified by an automated hematology analyzer and flow cytometry, respectively. Using Spearman's rank test, we evaluated the relationships between preharvest HPCs, CD34+ cell counts, and CD34+ cell yields in the apheresis product. A receiver operating characteristic (ROC) curve analysis was used to identify the cutoff value of HPC for adequate mobilization and harvest yield. RESULTS: The HPC count had a moderate correlation with the preharvest CD34+ cell count (r = 0.502, p < 0.001), and an HPC count of more than 21.3 × 10⁶/L could exclude poor mobilization (<20 × 10⁶ CD34+ cells/L) with sensitivity and specificity of 89.2 and 83.3%. However, the relationship between HPC count and CD34+ cell yield was not marked (r = 0.321, p < 0.001). The area under the curve for HPCs was significantly smaller than the preharvest CD34+ cell count on the ROC curve for predicting adequate harvest yield (>10 × 10⁶ CD34+ cells/L of processed blood volume, 0.678 vs. 0.850, p = 0.001). CONCLUSION: Although the preapheresis HPC count could predict mobilization in healthy donors before leukapheresis, it may not be a superior index for predicting CD34+ cell yield compared with the preharvest CD34+ cell count.     

Hematopoietic progenitor cell count, but not immature platelet fraction value, predicts successful harvest of autologous peripheral blood stem cells

Mobilized stem cells in the peripheral blood (PB) must be efficiently harvested at the appropriate time before autologous PB stem cell (PBSC) transplantation. Enumeration of CD34+ cells in the PB before apheresis predicts the number of PBSCs that can be collected, but the cytometric techniques used are complex and expensive. Therefore, it is necessary to identify an alternative to the CD34+ cell count in PBSC harvest-time monitoring. Fully automated flow cytometry using blood cell counters now allows reliable quantification of immature myeloid cells in the PB, referred to as hematopoietic progenitor cells (HPC), and reticulated platelets, expressed as the immature platelet fraction (IPF). Immature or reticulated platelets are thought to correlate with thrombopoietic activity of the marrow. Following a chemotherapy nadir, the recovery of white blood cell and platelet counts has been used to determine the right time for apheresis. Therefore, we examined whether the HPC count and IPF value could be used to predict PBSC mobilization in 20 patients with hematological malignancies. The HPC count was found to be correlated with the CD34+ cell count (r = 0.84, P < 0.01), whereas the IPF value was not (r = 0.37, P = 0.44). Therefore, the HPC count, but not the IPF value, is a possible predictor of the timing of autologous stem cell transplantation.     

A specific time course for mobilization of peripheral blood CD34+ cells after plerixafor injection in very poor mobilizer patients: impact on the timing of the apheresis procedure

BACKGROUND: This report describes the specific kinetics of the peripheral blood (PB) CD34+ cell concentration in a selected group of very poor stem cell mobilizer patients treated with granulocyte–colony‐stimulating factor (G‐CSF) and plerixafor and determines the kinetics' impact on apheresis. STUDY DESIGN AND METHODS: All patients had previously experienced at least two failures of mobilization (without use of plerixafor). The present salvage therapy consisted in the administration of 10 µg/kg/day G‐CSF for 5 days added to a dose of plerixafor administered at between 5 a.m. and 6 a.m. on Day 5. The PB CD34+ cell counts were tested every 3 hours thereafter. Apheresis was initiated as soon as the PB CD34+ cell count reached 10 × 10⁶/L. RESULTS: A PB CD34+ cell count higher than 10 × 10⁶/L was observed as soon as 3 hours after plerixafor administration in 10 of the 11 patients who reached this threshold at some point in the monitoring process. Interestingly, all patients presented an early decrease in the PB CD34+ cell count 8 to 12 hours after plerixafor administration (below 10 × 10⁶/L for seven patients). CONCLUSION: Had such patients been tested for PB CD34+ cell mobilization according to conventional criteria (i.e., 11 hr after plerixafor administration), apheresis would not have been performed at the optimal timing. For very poor stem cell mobilizer patients, early monitoring of PB CD34+ cell count may be required for the optimal initiation of apheresis.     

Does continuous flow apheresis influence viability in allogeneic hematopoietic stem cell harvest?

One of the important clinical variables determining the success of hematopoietic stem cell transplantation is the number of viable CD34+ stem cells transfused to the patient. G-CSF mobilized peripheral blood stem cells from 17 healthy donors were collected by continuous flow apheresis. The median (range) proportions of early apoptotic (Annexin V-FITC(pos)/7-AAD(neg)) and viable (Annexin V-FITC(neg)/7-AAD(neg)) CD45(dim)CD34+ stem cells were 1.5 (0.9-3.7)% and 97.7 (82.8-100)% in the peripheral blood before apheresis and 2.6 (0.8-7.9)% and 97.3 (91.9-99)% in the apheresis products, respectively. Despite an increase in the number of apoptotic cells among all cell compartments, this was statistically significant only in CD34+ cells and granulocytes. The majority of the cells still retained their viability.     

Kinetics of peripheral blood stem cell collection in large-volume leukapheresis for pediatric patients undergoing chemotherapy and adult patients before chemotherapy

The present study investigated the kinetics involved in collection CD34+ cells and colony-forming units-granulocyte-macrophages (CFU-GMs) during large-volume leukapheresis (LVL) in pediatric patients with malignancies and attempted to correlate the number of cells with the processed blood volume. In addition, adult cases were also examined using the same continuous flow blood cell separator to investigate the difference between children and adults. We examined 5 pediatric patients who had undergone chemotherapy before apheresis and 3 adult patients who were scheduled to undergo chemotherapy following apheresis. Collection was performed using a continuous-flow blood cell separator. Patients received granulocyte-colony-stimulating factor (G-CSF) to mobilize peripheral blood stem cells (PBSCs), except in the case of acute myelocytic leukemia. The processed blood volume was set to approximately 300 ml in children and 500 ml/kg of body weight in adults and the leukapheresis component was collected when approximately 50 ml of blood was processed. Six sequential samples were taken from each component in pediatric patients and 10 sequential samples from adults to obtain CD34+ cells and CFU-GMs. Counts of mononuclear cells (MNCs) and CD34+ cells in peripheral blood were measured just before and after each apheresis. Hemoglobin, hematocrit, and platelet counts in peripheral blood were monitored during apheresis. A total of 11 collections were performed for pediatric patients. The mean total CD34+ cells and CFU-GMs in each fractionated yield did not show a remarkable increase with increasing volume of blood processed. In adults, the kinetics of CD34+ cells in each fractionated yield were determined on a continuous basis and CFU-GMs increased during the course of apheresis. In pediatric patients, circulating MNCs and CD34+ cells were stable during apheresis, whereas in adult patients these cells decreased in the peripheral blood after apheresis. In both pediatric and adult patients, the platelet count in the peripheral blood decreased after apheresis. In contrast to adults, in pediatric patients who had been undergone chemotherapy, the collection efficiency did not appear to increase with increased volume of blood processed. Moreover, there was a marked platelet reduction in peripheral blood following apheresis. We conclude that the kinetics of collecting PBSCs by continuous flow blood cell separator is different between pediatric cases and adults cases. The application of LVL may be prudent in some children with malignancies, including those with a low platelet count and low body weight.     

Peripheral blood stem cell apheresis for allogeneic transplants: Ibni Sina experience

BACKGROUND: The rate of utilizing peripheral blood stem cells (PBSC) as a source for allogeneic stem cells is growing rapidly. We aimed to demonstrate our 4 years experience as the largest apheresis center in Turkey and analyzed the content of the apheresis material. PATIENTS AND METHODS: From 1998 to the end of April 2002, 151 leukopheresis procedures were performed on 116 healthy donors (M/F:66/50) with a median age of 30 years (14-53). The HLA identical sibling donors received rhG-CSF 10 microg/kg/day sc. for 4 days and at the 5th day leukopheresis was started until collecting >4 x 10e6/kg CD34+ cells. Two times the donors' total blood volume was processed in 195 min (178-245) on continuous flow cell separators using peripheral venous access. RESULTS: Preapheresis WBC was 51.5 x 10e9/L (range, 13.11-91.3). Mono nuclear cell, CD34 and CD3 quantity of the harvest material were 5.35 x 10e8/kg (range, 0.45-23.46), 6.4 x 10e6/kg (range, 2.49-33.27) and 2.79 x 10e8/kg (range, 0.46-30.95), respectively. We were able to reach the target CD34 count after 1st cycle in 39% and 2nd cycle 61% of the procedures. In all donors with a peripheral blood CD34 count >80/mcl we succeeded to collect enough stem cells with only one leukopheresis. CONCLUSION: Collection of peripheral blood stem cells with continuous flow cell separators is well tolerated, with no mobilization failures or poor mobilizers. We collected high values of CD34+ cells (med. 6.4 x 10e6/kg) at the expense of high CD3+lymphocytes (med. 2.79 x 10e8/kg), which may increase the risk of acute and chronic GVHD after allogeneic hemapoietic cell transplantation.     

Integration of biological, procedural, apheresis principles of peripheral blood stem cell transplantation programs

Collection and use of peripheral blood stem cells have rapidly replaced harvesting of pelvic bone marrow for transplant protocols. The mobilization of progenitor populations into the peripheral blood by chemotherapy and/or cytokine stimulation of marrow hematopoietic production has made it possible, in general, to collect larger quantities of progenitor populations than obtained in a single harvest of marrow. Technological advances through flow cytometry and generation of monoclonal antibodies to identify CD34 antigen expression on cells has provided a rapid means of assessing leukapheresis products for the presence of progenitor populations and has largely replaced the laborious 14 day culture assays' to measure colony forming units. Unlike apheresis platelet collection, where the yields are predictable through integration of donor biological variability, total volume of blood processed, and machine efficiency, CD34+ cell yields are not predictable. This has led to great diversity in stem cell collection procedures. Analyses of the same variables used to predict platelet yields, if applied to CD34+ cell collection, might lead to useful algorithms for development of standardized guidelines for stem cell collection.     

Prospective flow cytometric evaluation of nucleated red blood cells in cord blood units and relationship with nucleated and CD34(+) cell quantification

BACKGROUND: Cord blood (CB) represents an alternate source of stem cells in transplantation. Nucleated red blood cells (NRBCs) are a physiological subset of CB population. Although it is important to have an accurate estimate of CD34(+) cell number, NRBCs could compromise white blood cell count and interfere with CD34(+) cell quantification. STUDY DESIGN AND METHODS: A total of 826 CB units were analyzed for total nucleated cells (TNCs), NRBCs, and CD34(+) cells by flow cytometry. NRBCs were also counted conventionally by manual microscopy. Percentages of CD34(+) cells corrected by NRBC count (CD34+c) were determined as follows: %CD34+c = CD34(+)/CD45(+) (x10(6))/(TNCs (x10(8)) - NRBCs (x10(8))). RESULTS: The mean percentages of CD34+ cells and NRBCs were 0.27 percent (range, 0.01%-1.25%) and 7.64 percent (range, 0.13%-84%), respectively. Comparison between flow cytometric and microscopic NRBC count showed a regression of y = 0.685 + 0.719x and a coefficient of determination of r(2) = 0.721. When corrected with NRBC count, the mean percentage of CD34(+) c cells was 0.295 percent (p = 0.0008 compared with CD34(+)%) and mean TNCc count was 14.8 x 10(8) (p < 10(-4) compared to TNC count). CONCLUSION: The determination of NRBCs with a flow cytometric method might represent a new strategy for providing satisfactory quality assurance controls of CB products.     

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.     

Mobilization of hemopoietic stem cells with high-dose methotrexate plus granulocyte-colony-stimulating factor in patients with primary central nervous system lymphoma

BACKGROUND: High‐dose therapy with autologous stem cell support after standard dose induction is a promising approach for therapy of primary central nervous system lymphoma (PCNSL). High‐dose methotrexate (HD‐MTX) is a standard drug for induction of PCNSL; however, data about the capacity of HD‐MTX plus granulocyte–colony‐stimulating factor (G‐CSF) to mobilize hemopoietic progenitors are lacking. STUDY DESIGN AND METHODS: This investigation describes the data from stem cell mobilization and apheresis procedures after one or two cycles of HD‐MTX for induction of PCNSL within the East German Study Group for Haematology and Oncology 053 trial. Eligible patients proceeded to high‐dose busulfan/thiotepa after induction therapy and mobilization. RESULTS: Data were available from nine patients with a median age of 58 years. The maximal CD34+ cell count per µL of blood after the first course of HD‐MTX was 13.89 (median). Determination was repeated in six patients after the second course with a significantly higher median CD34+ cell count of 33.69 per µL. Five patients required two apheresis procedures and in four patients a single procedure was sufficient. The total yield of CD34+ cells per kg of body weight harvested by one or two leukapheresis procedures was 6.60 × 10⁶ (median; range, 2.68 × 10⁶‐15.80 × 10⁶). The yield of CD34+ cells exceeded the commonly accepted lower threshold of 3 × 10⁶ cells per kg of body weight in eight of nine cases. Even in the ninth, hemopoietic recovery after stem cell reinfusion was rapid and safe. CONCLUSION: HD‐MTX plus G‐CSF is a powerful combination for stem cell mobilization in patients with PCNSL and permits safe conduction of time‐condensed and dose‐intense protocols with high‐dose therapy followed by stem cell reinfusion after HD‐MTX induction.     

A randomized clinical trial comparing granulocyte-colony-stimulating factor administration sites for mobilization of peripheral blood stem cells for patients with hematologic malignancies undergoing autologous stem cell transplantation

BACKGROUND: A study was undertaken to investigate whether granulocyte–colony‐stimulating factor (G‐CSF) injection in lower adipose tissue–containing sites (arms and legs) would result in a lower exposure and reduced stem cell collection efficiency compared with injection into abdominal skin. STUDY DESIGN AND METHODS: We completed a prospective randomized study to determine the efficacy and tolerability of different injection sites for patients with multiple myeloma or lymphoma undergoing stem cell mobilization and apheresis. Primary endpoints were the number of CD34+ cells collected and the number of days of apheresis. Forty patients were randomly assigned to receive cytokine injections in their abdomen (Group A) or extremities (Group B). Randomization was stratified based on diagnosis (myeloma, n = 29 vs. lymphoma, n = 11), age, and mobilization strategy and balanced across demographic factors and body mass index. RESULTS: Thirty‐five subjects were evaluable for the primary endpoint: 18 in Group A and 17 in Group B. One evaluable subject in each group failed to collect a minimum dose of at least 2.0 × 10⁶ CD34+ cells/kg. The mean numbers of CD34+ cells (±SD) collected were not different between Groups A and B (9.15 × 10⁶ ± 4.7 × 10⁶/kg vs. 9.85 × 10⁶ ± 5 × 10⁶/kg, respectively; p = NS) after a median of 2 days of apheresis. Adverse events were not different between the two groups. CONCLUSION: The site of G‐CSF administration does not affect the number of CD34+ cells collected by apheresis or the duration of apheresis needed to reach the target cell dose.