Crude collection efficiency of CD34+ hematopoietic stem cell apheresis

Understanding the apheresis principles for harvesting hematopoietic stem cells (HSCs) is critical for performing efficient procedures. However, despite significant advances in estimating the collection efficiency (CE) of aphereses, many confounding factors still need to be addressed in the classical calculations. The CE values are unrestricted, and many procedures exhibit CEs of a given cell population greater than 100%. This report introduces a simple equation that estimates the “crude” CE, which ranges from 0% to 100% and intrinsically considers the contribution of donor-related variables such as the pre-procedure mobilization and intra-apheresis recruitment of CD34⁺ cells (as a convenient marker for HSCs), as well as the performance of the apheresis system itself.     

Analysis of CD34+ cell collection using two mobilization regimens for newly diagnosed multiple myeloma patients reveals the separate impact of mobilization and collection variables

Mobilization regimens for CD34+ cells have generally been judged successful based on the number of cells collected without evaluating mobilization separately from collection. Using retrospective data for patients who collected CD34+ cells on Total Therapy protocols 3a/3b (VTD‐PACE) and Total Therapy 4/5 using a novel regimen that added low dose melphalan to VTD‐PACE (MVTD‐PACE), we analyzed mobilization and collection variables separately. A significant difference favoring MVDT‐PACE was found in mean CD34+ cells/µL on day 2 of collection and in mean ratio of CD34+ cells/µL on day 2 to day 1. However, because apheresis variables and growth factor dose during collection were manipulated to optimize individual collections, the two regimens were not significantly different when the mean total CD34+ cells ×10⁶/kg collected was compared. Thus, when evaluating a chemotherapy regimen or new growth factor for mobilization, it is important to realize that total CD34+ cells collected is dependent on both mobilization and collection variables. J. Clin. Apheresis 29:251–255, 2014. © 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.     

Successful autologous peripheral blood stem cell collection using large volume leukapheresis in patients with very low or undetectable peripheral blood CD34+ progenitor cells

Autologous stem cell transplantation provides some patients with hematolymphoid and solid organ malignancies an opportunity for cure. Management of peripheral hematopoietic stem cell (HSC) collections differs among institutions, especially if a very low pre-procedure peripheral blood CD34+ cell count (PBCD34) is demonstrated. This study retrospectively analyzed results of large-volume peripheral HSC collections in 91 patients over approximately two years. Fifteen patients with PBCD34 < 10 × 10e6/l (eleven with undetectable PBCD34) were compared to 76 patients with higher counts on the first collection day (adequate mobilizers). The poor mobilizer group had significantly lower pre-collection WBC and platelet counts as well as collection yields. However, most patients with PBCD34 < 10 × 10e6/l (80 %) collected the minimum target for HSC transplant (2.0 × 10e6 CD34+ cells/kg) in <5 consecutive days of collection, and those who did collect the minimum successfully underwent autologous transplantation, with hematopoietic engraftment and long-term survival comparable to the adequate mobilizers. Successful HSC collection may often be achieved regardless of d 1 PBCD34 counts.     

Inverse relationship between patient peripheral blood CD34+ cell counts and collection efficiency for CD34+ cells in two automated leukapheresis systems

BACKGROUND: The purpose of this study was to analyze the CD34 cell collection efficiency (CE) of automated leukapheresis protocols of two blood cell separators (Spectra, COBE [AutoPBSC protocol] and AS104, Fresenius [PBSC-Lym, protocol]) for peripheral blood progenitor cell (PBPC) harvest in patients with malignant diseases. STUDY DESIGN AND METHODS: PBPCs were collected by the Spectra AutoPBSC protocol in 95 patients (123 collections) and the AS104 PBSC-Lym protocol in 87 patients (115 harvests). Patients underwent a median of one (range, 1-4) conventional-volume apheresis procedure of 10.8 L (9.0-13.9) to obtain a target cell dose of > or =2.5 x 10(6) CD34+ cells per kg. RESULTS: The median overall CD34 CE was significantly better on the AS104 than on the Spectra: 55.8 percent versus 42.4 percent (p = 0.000). This was also true below (59.2% vs. 50.1%; p = 0.022) and above (51.2% vs. 41.3%; p = 0.001) the preleukapheresis threshold of 40 CD34+ cells per microL needed to collect a single-apheresis autograft. However, at > or =40 circulating CD34+ cells per microL, both cell separators achieved the target of > or =2.5 x 10(6) CD34+ cells per kg. The CD34 CE dropped significantly, from 59.2 percent at <40 cells per microL to 51.2 percent at > or =40 cells per microL on the AS104 (p = 0.017) and from 50.1 percent to 41.3 percent on the Spectra (p = 0.033). CONCLUSION: Whereas the CD34 CE was significantly different with the AS104 and the Spectra, the CD34 CE of both machines correlated inversely with peripheral blood CD34+ cell counts, showing a significant decline with increasing numbers of circulating CD34+ cells. Nevertheless, at > or 40 preapheresis CD34+ cells per microL, sufficient hematopoietic autografts of > or =2.5 x 10(6) CD34+ cells per kg were harvested by a single conventional-volume (11 L) leukapheresis on both cell separators.     

化疗后恰当时机使用G-CSF能显著提高自体外周血干细胞移植物中CD34~+细胞的含量

本研究旨在观察COAEP化疗后选择不同时机使用G-CSF对动员自体外周血干细胞(PBSC)产率的影响。选择39例恶性淋巴瘤(NHL和HD)或多发性骨髓瘤(MM)患者,接受相同的动员化疗方案(COAEP),包括CTX400mg/m2d1,VLB2mg/m2d1,Ara-C60mg/m2×d1-5,VP-16 60mg/m2×d1-5,prednisone40mg/m2×d1-5。历史对照组(12例)在化疗后外周血白细胞降至最低点首次回升时使用G-CSF(filgrastim)。试验组(27例)在外周血白细胞稳定回升(白细胞在首次回升后仍会出现波动2-3天)时使用G-CSF。G-CSF以5μg/kg每天1次皮下注射直至最后1次PBSC采集前。2组患者开始使用G-CSF后每日进行血常规检查,当白细胞总数大于10.0×109/L,单个核细胞(MNC)大于1.0×109/L时使用COBE血细胞分离机,以自动干细胞分离程序采集PBSC。结果表明,2组病例都使用了烷化剂(累积剂量无统计学差异),试验组获得26.4×106/kg CD34+细胞,显著高于历史对照组3.1×106/kg CD34+细胞(p=0.0031)。结论...     

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.     

The use of hematocrit level for predicting the efficiency of peripheral blood CD34+ cell collection after G‐CSF Mobilization in Healthy Donors

Recently, peripheral blood stem cell (PBSC) has been widely used and replaced bone marrow (BM) as the stem cell source in allogeneic hematopoietic stem cell transplantation (HSCT) because of a more rapid engraftment, easier accessibility, and lower risk of donor complications. We, therefore, report the predicting factors for the high PBSC harvest yields in 50 healthy donors. Among the 50 donors, median collected CD34⁺ cell number was 4.6 × 10^6/kg (1.5–16.3 × 10⁶/kg). Number of circulating CD34+ cells and hematocrit (HCT) level increased parallelly whereas peripheral CD34+ cell numbers were decreased with increasing donor age. In univariate analysis, HCT level≥ 35.5% at the time of PBSC collection was significantly associated with high PBSC number (≥ 5.0 × 10⁶ cells/kg) and donor aged <30 years was significantly associated with collected CD34+ cells ≥ 6.0 × 10⁶/kg, P = 0.03. HCT level ≥35.5% was an independent parameter for high WBC count (≥50 × 10⁹/L), P < 0.05. None of donor who had both HCT < 35.5% and WBC < 50 × 10⁹/L had circulating CD34+ cells ≥ 5.0 × 10⁶/kg. Platelet count ≥ 200 × 10⁹/L was found significantly in donors with WBC ≥ 40 × 10⁹/L (P = 0.03) and HCT ≥ 35.5%, P < 0.05. Collected PBSC number tended to be higher in our donors with high levels of HCT, WBC, and platelet. We also found that HCT and platelet levels in our donors decreased after receiving G‐CSF administration compared with the initial complete blood counts (CBC) results. We, therefore, concluded that HCT level at the time of initiation leukapheresis was an important predictor for PBSC collection yields. J. Clin. Apheresis 30:329–334, 2015. © 2015 Wiley Periodicals, Inc.     

A functional hierarchy among the CD34+ hematopoietic cells based on in vitro proliferative and differentiative potential of AC133+CD34(bright) and AC133(dim/)-CD34+ human cord blood cells

The 5-transmembrane receptor AC133 is expressed on a subpopulation of human hematopoietic cells that includes the CD34(bright) cells. We evaluated the developmental potential of AC133+CD34(bright) and AC133(dim/-)CD34+ cells isolated from 5 cord blood (CB) samples by studying the in vitro proliferative and differentiative potential of each population in both progenitor and mature cell expansion cultures. Seven-day culture of AC133+CD34(bright) cells with a cytokine combination favoring primitive progenitor cells causes a significant increase in CD34+, CFU-C and noncycling stem/progenitor cells HPP-Q (High Proliferative Potential-Quiescent), whereas culture of AC133(dim/-)CD34+ cells shows a limited increase in committed progenitor cells only. HPP-Q cells were not found in freshly isolated AC133(dim/-)CD34+ nor in expanded CD34+ cells derived from AC133(dim/-)CD34+ cells. No statistically significant difference was observed between the 1-week expanded AC133+ and the initial AC133+CD34(bright) cells regarding their clonogenic efficiency (CE), while expanded CD34+ cells derived from AC133(dim/-)CD34+ cells exhibited a decreased CE. Subexpansion of the reselected AC133+ derived from AC133+CD34(bright) cells reveals a further increase of stem/progenitor cells and the 14-day expanded AC133+ cells reveal an unchanged CE. Subexpansion of reselected 7-day CD34+ cells derived from AC133(dim/-)CD34+ cells was not possible. Culture of AC133+CD34(bright) cells in cytokines that favor megakaryopoiesis or erythropoiesis resulted in a significant expansion of CD41+ and CD71+ cells, respectively; AC133(dim/-)CD34+, in comparison, showed a limited potential to megakaryocytic differentiation and a decreased production of erythroid cells. Our data indicate that early high proliferating stem/progenitor cells and early committed progenitors are present in AC133+CD34(bright) cells, but not in AC133(dim/-)CD34+ cells; the latter represent late committed progenitors with limited proliferative potential.     

Collection efficiencies of MNC subpopulations during autologous CD34+ peripheral blood progenitor cell (PBPC) harvests in small children and adolescents

There is increasing demand for mononuclear cell (MNC) harvests not only for PBPC but also for immune therapies using dendritic cells and donor lymphocytes. We determined the collection efficiencies (CE) of various MNC subpopulations during CD34+ cell harvests using a Fenwal CS 3000 Plus Omnix system in small children and adolescents. The cell content of 140 leukapheresis products (LP) was prospectively evaluated in 45 pretreated patients with solid tumors and hematological malignancies. The median age was 12 years (range 0.8-22), and the median body weight (BW) 43 kg (range 9-92). Depending upon the BW of the patients, the media used for priming were saline (SP) in 86, human albumin (HA, HAP) in 10, and packed red blood cells (BP) in 44 apheresis procedures. The major nucleated cell (NC) fractions collected were monocytes (52% of NC) and CD3+ T cells (26%). The median cell yield for monocytes was 174 * 10(6)/kg (range 24-613) representing a CE of 55%. The median number of CD3(+) T cells was 84 * 10(6)/kg (range 5.6-380; CE = 74%). CD34+ cells represented a very small cell fraction of the LP (1.3% of NC), with a median yield of 4.2 * 10(6)/kg (range 0.2-87) and a CE of 63%. The cell yield of various MNCs was significantly correlated with the cell count in the peripheral blood (PB) and with the blood volume processed (ANOVA, P < 0.0001). No influence on the CE was observed for the priming procedure, the patients' age or sex, or the other adaptations used in the harvesting protocol. In conclusion, the Fenwal CS 3000 Plus OMNIX system with the CD34+ cell program and the described adaptations, is also predictably useful for harvest of monocytes or lymphocytes in pediatric patients. We present regression equations that predict the cell yield of various MNC subpopulations in apheresis products.     

Predictive factors that affect the mobilization of CD34(+) cells in healthy donors treated with recombinant granulocyte colony-stimulating factor (G-CSF)

No specific characteristics have been identified as predictors of peripheral blood stem cells (PBSC) mobilization in healthy donors. In this study, clinical characteristics and laboratory data for 122 healthy donors who underwent apheresis on day 5 of treatment with recombinant granulocyte colony-stimulating factor (G-CSF) were retrospectively analyzed for correlations with CD34(+) cell mobilization. The variables that were analyzed included age, sex, body weight, basal complete blood count, and maximum white blood count (WBC) before apheresis, G-CSF type, and dosage. Median age and body weight were 42.5 years (range 16-65) and 72.5 kg (range 47-121), respectively. By univariate analysis, male sex (P = 0.007), body weight (< or = 70 vs. >70 kg, P = 0.04), and donor's age (< or = 50 vs. > 50 years; P = 0.015) were correlated with the number of CD34(+) cells mobilized. By multivariate analysis, donor's age and male sex were the only two variables that significantly predicted a high CD34(+) cell level. In conclusion, our data suggest that male sex and younger age are the only factors that significantly affect CD34(+) mobilization in healthy donors.     

A cell-kinetic model of CD34+ cell mobilization and harvest: development of a predictive algorithm for CD34+ cell yield in PBPC collections

BACKGROUND: Mobilization and homing of PBPCs are still poorly understood. Thus, a sufficient algorithm for the prediction of PBPC yield in apheresis procedures does not yet exist. STUDY DESIGN AND METHODS: The decline of CD34+ cells in the peripheral blood during apheresis and their simultaneous increase in the collection bag were determined in a prospective study of 18 consecutive apheresis procedures. A cell-kinetic, four-compartment model describing these changes was developed. Retrospective data from 136 apheresis procedures served to further improve this model. A predictive algorithm for the yield was developed that considered the sex, weight, and height of the patient, the number of CD34+ cells in peripheral blood before apheresis, the inlet flow, and the duration of the apheresis. The accuracy of this algorithm was evaluated by comparison of the predicted and the observed yields of CD34+ cells in 105 prospective autologous and 148 retrospective allogeneic apheresis procedures. RESULTS: The correlation between predicted and observed yields was good for the autologous and allogeneic groups with a correlation coefficient (r) of 0.8979 and 0.8311 (p<0.0001), respectively. The regression is described by the equations log (measured value [m]) = 1.0118 + 0.8595 x log (predicted value [p]) for the autologous and log (m) = 2.226 + 0.7559 x log (p) for the allogeneic group. The respective equations for the zero-point regression are log (m) = 1.014 x log (p) and log (m) = 1.026 x log (p). The probability that the measured value was 90 percent or more of the predicted value was 83.8 percent for the autologous and 90.5 percent for the allogeneic apheresis procedures. CONCLUSION: The predictive accuracy of the algorithm and the slope of the zero-point regression curve were higher for allogeneic than autologous PBPC collections. The predictive algorithm may be a useful tool in PBPC harvest, enabling the adaptation of the size of the apheresis to the needs of each patient.