A discrepancy between the instantaneous and the overall collection efficiency of the fenwal CS3000 for peripheral blood stem cell apheresis

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.

Collection efficiency in apheresis

Significant advances in procedural information displayed by current apheresis machines have been made, but analyses of cell collection efficiency (CE) still rely on calculations done by apheresis professionals. Accordingly, understanding CE equations can support the optimization of apheresis techniques and identification of incidents that could impact the procedure's effectiveness. This report summarizes classical and novel CE analyses applied to apheresis exemplified by an actual case of hematopoietic progenitor cell collection. In addition to the apheresis yield and most common CE1 and CE2 formulas, we present the instantaneous and corrected CE, fold enrichment, collection throughput, collection rate and its variants, average inlet rate, classical and adjusted captured cells, recruitment pool, recruitment factor, recruitment coefficient, blood component loss, predictive apheresis yield, and performance ratio calculations. Moreover, the mathematical relationship between these CE equations is also shown, which can be helpful in many apheresis procedures.

Comparison of two apheresis systems for autologous stem cell collections in pediatric oncology patients

BACKGROUND

Peripheral stem cell collections can be challenging in the pediatric population and respective experience is limited. Since February 2015 our institution is utilizing the new Spectra Optia (Optia) apheresis device, which has replaced the former COBE Spectra (COBE) device. As a quality initiative we collected and compared collection efficiency (CE2) and other collection variables between the two devices.

STUDY DESIGN AND METHODS

In this retrospective study we collected and compared clinical, laboratory, and technical collection data from stem cell collection procedures done with the Optia and COBE devices. The collected data included patient demographics, precollection peripheral CD34+ cell counts, total CD34+ cells collected, complete blood count, electrolytes before and after collection, side effects attributed to the collection, total blood volumes processed (TBVs), collection times, and calculated CE2 and collection ratios.

RESULTS

Forty-one collection procedures performed on 29 pediatric patients with the Optia device were compared to 41 collections performed on 27 patients with the COBE device. The TBVs through the Optia device were significantly smaller than the COBE (3.9 ± 0.2 × TBV vs. 5.5 ± 0.1 × TBV, respectively; p < 0.001), requiring significantly less anticoagulant and providing similar amounts of stem cells while collection times were significantly shorter (mean, 238 ± 9 min vs. 264 ± 9 min, respectively; p < 0.05). Collections on the Optia caused significantly smaller reductions of plasma calcium and magnesium. No significant side effects attributed to the procedure were noted.

CONCLUSION

Stem cell apheresis with the Optia device in children is safe and feasible with smaller blood volumes with shorter collection times.

Autologous peripheral blood stem cell harvest: Collection efficiency and factors affecting it

BACKGROUND

Harvest of hematopoietic progenitor cells via leukapheresis is being used increasingly for transplants in India. Adequate yield of cells per kilogram body weight of recipient is required for successful engraftment. Collection efficiency (CE) is an objective quality parameter used to assess the quality of leukapheresis program. In this study, we calculated the CE of the ComTec cell separator (Fresenius Kabi, Germany) using two different formulae (CE1 and CE2) and analyzed various patient and procedural factors, which may affect it.

MATERIALS AND METHODS

One hundred and one consecutive procedures in 77 autologous donors carried out over 3 years period were retrospectively reviewed. Various characteristics like gender, age, weight, disease status, hematocrit, preprocedure total leukocyte count, preprocedure CD34 positive (CD34+) cells count, preprocedure absolute CD34+ cell count and processed apheresis volume effect on CE were compared. CE for each procedure was calculated using two different formulae, and results were compared using statistical correlation and regression analysis.

RESULTS

The mean CE1 and CE2 was 41.2 and 49.1, respectively. CE2 appeared to be more accurate indicator of overall CE as it considered the impact of continued mobilization of stem cells during apheresis procedure, itself. Of all the factors affecting CE, preprocedure absolute CD34+ was the only independent factor affecting CE.

CONCLUSION

The only factor affecting CE was preprocedure absolute CD34+ cells. Though the mean CE2 was higher than CE1, it was not statistically significant.

Unstimulated leukapheresis in patients and donors: comparison of two apheresis systems

BACKGROUND

Unstimulated mononuclear cell (MNC) apheresis plays a role in the generation of donor lymphocytes (DLIs; healthy donors) and in extracorporeal photopheresis (ECP; patients). The new apheresis system Spectra Optia MNC has been shown in small studies to be capable of performing the desired cell collections, but larger data sets from real-life clinical apheresis procedures are lacking.

STUDY DESIGN AND METHODS

Presented are comparative data from DLI collections randomly performed with either the new technology or a clinical standard technology, COBE Spectra MNC, as well as data from patients with chronic graft-versus-host disease undergoing MNC collections alternating between the two apheresis systems to generate products for ECP. Target cell yield and collection efficiency, product volume, nontarget cell contamination, platelet (PLT) attrition, and some process variables such as process volume and time were analyzed.

RESULTS

For most relevant apheresis outcomes, differences between the devices were at best marginal. Spectra Optia MNC collections in patients, but not in donors, took 10% longer to achieve the target process volume. Not unexpectedly, given previous observations for granulocyte-colony-stimulating factor-stimulated leukapheresis, the novel device collected smaller products with less red blood cell contamination. PLT attrition with Spectra Optia MNC was markedly lower in donors. ECP apheresis outcome variability was, to a significant degree, donor dependent, irrespective of the device used.

CONCLUSION

Based on more than 200 unstimulated apheresis procedures, we conclude that both apheresis systems are safe, robust, and equally suitable for unstimulated MNC collections. Both can be successfully run with manufacturer-recommended settings and algorithms.

Automatic interface-controlled apheresis collection of stem/progenitor cells: results from an autologous donor validation trial of a novel stem cell apheresis device

BACKGROUND

Cryopreserved hematopoietic progenitor cells collected by apheresis from granulocyte-colony-stimulating factor with or without chemotherapy-mobilized patients have become the preferred type of autograft to support treatment of diseases amenable to high-dose chemotherapy. A novel apheresis system, the Spectra Optia v.5.0 (CaridianBCT), was constructed to meet certain shortcomings of manual apheresis systems such as the COBE Spectra MNC (CaridianBCT), including the need for continuous optical or manual monitoring and readjustment of buffy coat position and sensitivity to inconsistent blood flow. By use of optical sensors, which provide real-time automatic interface (buffy coat) and collection line control, the Spectra Optia promises to automatically guide apheresis procedures, potentially freeing up operator time and reducing variability in collection efficiency (CE2).

STUDY DESIGN AND METHODS

In a two-center clinical trial, 35 autologous stem cell donors were subjected to apheresis with the Spectra Optia to validate feasibility and effectiveness of apheresis procedures. Results were compared to data from 80 autologous apheresis procedures with the COBE Spectra MNC.

RESULTS

Usability and function of the automatic interface management were excellent. CD34+ cell quality, assessed by viability staining, colony-forming unit-culture frequency, and engraftment kinetics, was equally good with both systems. CE2 of the Spectra Optia, calculated as CD34+ contents in the product divided by the number of CD34+ cells presented to the collection port, exceeded that of the COBE Spectra MNC. Spectra Optia product volumes were significantly smaller. Very high white blood cell and platelet counts modestly reduced CE2 with the Spectra Optia.

CONCLUSION

The Spectra Optia is a novel automatic apheresis system supporting autologous stem cell collection with at least equal efficiency and superior user-friendliness compared to the COBE Spectra MNC.

Change in CD34+ cell concentration during peripheral blood progenitor cell collection: effects on collection efficiency and efficacy

BACKGROUND

An understanding of factors affecting CD34+ cell collection efficacy is essential to minimize donor toxicity and cost.

STUDY DESIGN AND METHODS

Peripheral blood CD34+ cell (CD34) measurements were determined at various intervals before, during, and after automated cell collection (Cobe Spectra 6.0). The serial mean of multiple, intraprocedural CD34 levels was calculated for each procedure as an estimate of the mean, inlet-line CD34 level.

RESULTS

The CD34+ concentration fell a mean of 30 percent in the first 30 to 70 minutes of collection. The degree of decline was inversely correlated with donor blood volume (BV), but was not due to hemodilution. The mean of the CD34 level before and after collection slightly overestimated the serial mean CD34 level. Cell yields, normalized for the CD34 level before collection, were higher from donors with larger BVs.

CONCLUSIONS

The CD34 concentration rapidly decreased to a relative equilibrium level during the collection procedure. The degree of decrease in the CD34 level inversely correlated with the BV of the donor and was consistent with cell pooling in the collection set. The higher equilibrium CD34 levels in donors with larger BVs resulted in increased collection of CD34+ cells, and therefore, large-volume apheresis should be most efficient in these donors.

Mobilization and transplantation of peripheral blood stem cells

Two hundred nineteen patients underwent peripheral blood stem cell (PBSC) transplantation from 1990 to 1997. Stem cells were mobilized with cyclophosphamide (CY), or with CY plus Taxol or etoposide, followed by cytokines, and collected when leukocyte counts > or = 1,000/microl, or when CD34+ counts > or = 20/microl. On average, four to five collections were needed to obtain sufficient PBSC for engraftment. When CD34+ counts were used, the average number of collections decreased from 5.4 to 4.2. A discrepancy was noted in the extraction ratios and number of collections that depended on the optical density (I/O) setting of the leukapheresis machine. Patients collected at a setting of 100 had higher extraction ratios and required fewer collections (mean = 2.7) than those collected at 150 (mean = 4.4). This result was unexpected, because the entire mononuclear cell layer is collected at the higher I/O setting. Further analysis revealed that a larger volume of red cells was collected at 150 than at 100. These procedures used a small-volume collection chamber, so the chamber was apparently overloaded by RBC at the higher setting. More rapid recovery of neutrophil counts and platelet counts was seen in PBSC transplants than in autologous marrow transplants; moreover, PBSC transplant patients required fewer RBC and platelet transfusions. Sixteen out of 21 normal donors for allogeneic PBSC transplants gave adequate collections (> 2.5 x 10(6) CD34+ cells/kg), but three donors failed to yield > or = 1.5 x 10(6) CD34 cells/kg. This suggests an inherent difference among certain normal donors that may make PBSC mobilization difficult.

Factors affecting the efficiency of collection of CD34-positive peripheral blood cells by a blood cell separator

BACKGROUND

The yield of CD34-positive cells obtained from an apheresis procedure is determined, in part, by the efficiency of collection. Optimization of the efficiency of CD34-positive peripheral blood cell collection requires identification of predictive factors.

STUDY DESIGN AND METHODS

Demographic, stem cell collection, mobilization, and disease-related measures from autologous and allogeneic donors undergoing 252 progenitor cell apheresis procedures were retrospectively reviewed. Statistical relationships between CD34 collection efficiency and the various measures were determined by correlation and multiple linear regression analysis.

RESULTS

CD34 collection efficiency inversely correlated with the peripheral white cell count, hematocrit, and serum albumin concentration (R2 = 0.29). White cell count was the single best predictor of CD34 efficiency (R2 = 0.19). Donor groups with cytopenias (patients vs. normal donors; increased cycles of prior chemotherapy; bone marrow involvement; chemotherapy plus growth factor mobilization) had higher collection efficiencies. Only 29 percent of the variability in the data could be attributed to white cell count, hematocrit, and albumin concentration. The majority of the remaining variability was due to unexplained differences between donors.

CONCLUSION

CD34 collection efficiencies show considerable variation. Higher peripheral white cell counts, hematocrits, and/or albumin concentrations result in decreased CD34 collection efficiency, but most of the variability in the data is not accounted for by these three factors.

Intra-apheresis recruitment of blood progenitor cells in children

BACKGROUND

Determination of the optimal duration of apheresis requires a careful examination of blood progenitor cell (BPC) kinetics during apheresis. Intra-apheresis recruitment of BPCs should be evaluated.

STUDY DESIGN AND METHODS

Twenty-six apheresis procedures were performed in 13 children with various malignant disorders (ages, 10 months to 17 years; median, 7 years) to collect BPCs for autologous transplant, using a blood cell separator with 2 to 5.2 blood volumes processed. The subjects were divided into three groups according to age: below 1 year (n = 4), 2 to 10 years (n = 5), and 11 to 20 years (n = 4). BPCs were mobilized by a combination of chemotherapy and granulocyte-colony-stimulating factor (G-CSF; 2-7.5 micrograms/kg/day intravenous drip). The levels of circulating CD34+ cells and colony-forming units-granulocyte-macrophage (CFU-GM) were monitored to examine intra-apheresis recruitment. For every 50 mL per kg or 2 L of processed blood, 5-mL blood samples were collected via a central line.

RESULTS

In the first apheresis procedure, more CD34+ cells were mobilized by the procedure itself in the infant group than in the older groups, and the number of cells decreased with the subject's age. When the same analysis was made during the second apheresis procedure, performed 1 day later, the levels of both CD34+ cells and CFU-GM had decreased to below the preapheresis values in all of the populations. Cell yields in the second apheresis procedure were significantly lower than those in the first.

CONCLUSION

Although several factors prevent a reliable analysis, the data suggest that the intra-apheresis recruitment of BPCs may be age-specific; the continuous and prolonged supply of cells from the bone marrow to peripheral blood that occurs during apheresis is more predominant in infants, which leads to the collection of proportionately more BPCs in younger children than in their older counterparts.

Peripheral blood stem cell collection with reduced platelet loss to the patient/donor

Apheresis procedures that optimize peripheral blood stem cell (PBSC) harvesting also result in a significant loss of platelets to the patient/donor because of their similar densities. We compared the percent drop in platelet count and hemoglobin concentration in the patients before and after PBSC collection using two different collection chambers with the CS-3000. A modified plateletpheresis procedure was utilized. Seven patients underwent 38 PBSC collections during steady state hematopoiesis using the standard A-35 collection chamber. At the end of the procedure, a second low-speed centrifugation of the PBSC concentrate was performed in the manual mode, with siphoning out and return of the PRP to the patient through a transfer pack. For 14 patients who underwent 113 PBSC collections, a small volume collection chamber (SVCC) was substituted for the A-35 chamber and the second centrifugation step was omitted. These patients were also primed with 4 g/m2 of cyclophosphamide. The percent drop in platelet count in the patients after the collection procedures was significantly less in the SVCC group (20.4 +/- 9.1 vs. 36.0 +/- 12.3, P = 0.000), even after correction for the difference in the volume of blood processed between the two groups (3.2 +/- 1.4 vs. 3.9 +/- 1.3, P = 0.006). The percent drop in hemoglobin concentration was also less with the SVCC both before (5.4 +/- 3.8 vs. 11.7 +/- 3.0, P = 0.000) and after (0.8 +/- 0.6 vs. 1.3 +/- 0.3, P = 0.000) correction for the difference in the volume of blood processed.(ABSTRACT TRUNCATED AT 250 WORDS)

Collection efficiency on the Fenwal CS3000 when using filgrastim (recombinant methionyl human granulocyte colony-stimulating factor) as a peripheral blood stem cell mobilization agent

The collection efficiency (CE) of the Fenwal CS3000 in collecting peripheral blood stem cells during post-chemotherapy recovery phase ranges from 58% to 73%. Recently filgrastim (recombinant methionyl human granulocyte colony-stimulating factor [G-CSF]) has also been shown to be effective as a mobilization agent although mobilization occurs during elevated and not low normal leukocyte counts. We compared the mononuclear cell (MNC) CE and the myeloid progenitor cell (CFU-GM) CE among 11 patients with G-CSF mobilization (33 procedures) and 19 patients during recovery following myelosuppression chemotherapy (93 procedures). Pre-apheresis leukocyte, neutrophil, MNC, and PB CFU-GM counts were significantly higher in the G-CSF group, while the granulocyte percentage in the apheresis products was similar in both groups. Both MNC CE (81.8 +/- 4.5% vs. 64 +/- 2.4%) and CFU-GM CE (79.5 +/- 10.5% vs. 55.8 +/- 3.5%) were higher in the G-CSF group. Only the pre-apheresis MNC count showed an independently significant correlation for both CE (P < .001). The higher CE in the G-CSF group can only be partly explained by a rise in MNC count during apheresis. These data suggest that the blood cell separator works better with leukocytosis, and especially with a higher MNC count. The improvement in CE is another benefit of G-CSF mobilization over chemotherapy mobilization.

Yield and Collection Efficiency

Yield and collection efficiency are two important and strictly related aspects of an apheresis system. We have examined the various formulas, dwelling upon a few particular aspects of the collection of platelets, granulocytes and stem cells.