Comparison of COBE Spectra software version 4.7 PBSC and version 6.0 auto PBSC program

Optimization of leukocyte collection and monocyte isolation for dendritic cell culture

Leukapheresis is the method of choice to collect monocytes for dendritic cell (DC) culture. Improvement of cell separators and cell collection software have enabled the collection of 10(9) monocytes for the generation of monocyte-derived DCs, which is sufficient to prepare a DC vaccine series. However, leukapheresis works with the technique of differential centrifugation which is not applicable to selectively collect mononuclear cells of similar density. After leukapheresis, thus, additional preparation steps are required to isolate and enrich the desired monocyte population. The cell isolation and cultivation techniques depend on the quality of the original leukocyte harvest due to the monocyte yield and the content of residual erythrocytes and platelets. Monocyte elutriation from the leukapheresis product shows a high monocyte recovery of 80%. However, only 30% of the isolated monocytes can be developed into mature DCs. The factors responsible for DC maturation and the development of different DC subsets are the subject of current research.

A review of transfusion practice before, during, and after hematopoietic progenitor cell transplantation

The increased use of hematopoietic progenitor cell (HPC) transplantation has implications and consequences for transfusion services: not only in hospitals where HPC transplantations are performed, but also in hospitals that do not perform HPC transplantations but manage patients before or after transplantation. Candidates for HPC transplantation have specific and specialized transfusion requirements before, during, and after transplantation that are necessary to avert the adverse consequences of alloimmunization to human leukocyte antigens, immunohematologic consequences of ABO-mismatched transplantations, or immunosuppression. Decisions concerning blood transfusions during any of these times may compromise the outcome of an otherwise successful transplantation. Years after an HPC transplantation, and even during clinical remission, recipients may continue to be immunosuppressed and may have critically important, special transfusion requirements. Without a thorough understanding of these special requirements, provision of compatible blood components may be delayed and often urgent transfusion needs prohibit appropriate consultation with the patient's transplantation specialist. To optimize the relevance of issues and communication between clinical hematologists, transplantation physicians, and transfusion medicine physicians, the data and opinions presented in this review are organized by sequence of patient presentation, namely, before, during, and after transplantation.

Occurrence and severity of adverse events after autologous hematopoietic progenitor cell infusion are related to the amount of granulocytes in the apheresis product

BACKGROUND

Adverse events (AEs) after hematopoietic progenitor cell (HPC) infusion are rare but might be life-threatening. These reactions have traditionally been associated with the amount of infused cryoprotectant, but persistence of such events after dimethyl sulfoxide (DMSO) depletion has questioned this assumption.

STUDY DESIGN AND METHODS

The incidence of AEs on a cohort of 460 patients (490 HPC infusions) undergoing autologous DMSO-reduced HPC transplantation was prospectively evaluated. HPCs were collected from adult patients with various hematologic or solid malignancies. After quality control (QC) on fresh apheresis products and subsequent cryopreservation, HPC grafts were thawed and washed at the cell therapy facility. QC was performed on each graft after washing, and clinical data were collected for each infusion.

RESULTS

AEs were reported in 66 cases (13.5%) and were graded according to the NCI-CTC scale from 1 to 4. Although none of the factors associated with patient characteristics or infusion procedure were different between the two groups (no AE vs. occurrence of AE), it was found that the absolute number of granulocytes measured before freezing was considerably higher in the AE group. Furthermore, within this group, there was a strong correlation between the amount of granulocytes and the grading of the reaction.

CONCLUSION

This survey demonstrates that AEs occurring in the setting of DMSO-reduced HPC grafts are directly related to the amount of granulocytes and thus emphasizes the need for high-quality apheresis products so as to improve the safety of HPC infusion.

Accurate prediction of autologous stem cell apheresis yields using a double variable-dependent method assures systematic efficiency control of continuous flow collection procedures

BACKGROUND AND OBJECTIVES

Stem cell collection is a standard procedure for the procurement of autologous grafts to rescue myelosuppression induced by high-dose treatments. Accurate prediction of collection yields may contribute to optimize planning and quality control of collection.

MATERIALS AND METHODS

Data of 313 autologous haematopoietic stem cell (AHSC) evaluable collections performed in 208 patients with haematologic and non-haematologic neoplasms from seven centres were prospectively analysed to test the accuracy of yield predictions generated by a formula that required the input of peripheral blood (PB) CD34+ cell precount and desired PB volume to be processed. Data were matched in a standard linear regression, in a zero-point regression analysis and tested for prediction accuracy. Further 165 AHSC collections were analysed on a single-centre basis, using yield predictions as reference standards.

RESULTS

Analysis showed high levels of correlation between measured collection yields (my) and predictions (py) (R = 0.85; P = 0.000000) as well as high degree of prediction accuracy (my vs. py at paired t-test: P = 0.114781; median my/py ratio = 1.23). Analysis of additional 165 AHSC collections on a single-centre basis showed that the analysed centres had 70% or more measured yields comprising the 0.6-1.8 interval of the my/py ratio. The observance of the 'efficiency' my/py interval assured collection quality control in these centres confirming the reliability of the method.

CONCLUSIONS

This prediction method generates accurate and immediate yield predictions allowing collection planning and rapid efficiency control. As a consequence of our study, four centres out of seven use the described method to plan both leukapheresis number and single-procedure blood processing volume while the remaining three centres plan leukapheresis number on the basis of our predictions, maintaining a fixed single-procedure 200 ml/kg blood volume processing, according to their centre AHSC collection policy.

Leukapheresis for the extraction of monocytes and various lymphocyte subpopulations from peripheral blood: product quality and prediction of the yield using different harvest procedures

BACKGROUND AND OBJECTIVES

Leukapheresis of non-mobilized healthy donors is performed to harvest monocytes and lymphocyte subpopulations for use in various therapeutic regimens. In this methodological study, we compared two different leukapheresis programs, using equivalent volumes of processed blood over similar processing periods, to determine the influence of the procedures on the donor peripheral blood count and to establish the procedure that yields the highest quality product.

MATERIALS AND METHODS

The target variables obtained in 41 healthy blood donors who underwent short-term leukapheresis (80-105 min) were retrospectively compared. Twenty-one volunteers were processed on a COBE Spectra machine at the MNC setting and 20 volunteers were processed at the AutoPBSC setting. Data were collected on pre- and postleukapheresis samples and on the product.

RESULTS

AutoPBSC and MNC procedures resulted in a decrease of haemoglobin (5-7%), platelets (17-20%), monocytes (22%) and lymphocytes (23-27%), but not of granulocytes in peripheral blood. Both procedures produced nearly identical leucocyte and lymphocyte yields. AutoPBSC products contained a greater number of granulocytes, monocytes and red cells, but fewer platelets. The preleukapheresis values correlated with the yields for monocytes, T-helper and T-suppressor cells, B-lymphocytes and natural killer cells, but not for granulocytes or platelets.

CONCLUSIONS

Leukapheresis is a safe and efficient procedure for collecting large numbers of peripheral blood monocytes and different lymphocyte populations from non-mobilized donors. The two programs yield comparable leucocyte harvests. Based on our results, yields can be predicted from the peripheral cell counts.

Analysis of factors affecting PBPC collection in low-weight children with malignant disorders

BACKGROUND

PBPC collection in children weighing </=25 kg is hampered by technical and clinical problems related to vascular access, low total blood volume, anticoagulation, side effects, and psychological impact. The aim of this study was to analyze several clinical and technical factors, other than pre-apheresis CD34(+) count, that may affect PBPC collection in these low-weight children.

METHODS

Data from 88 leukaphereses performed in 45 children were analyzed, including pre-apheresis CD34(+) cell count, COBE Spectra software (version 4.7 versus 6.0), apheresis volume [standard versus large-volume leukapheresis (LVL)] and patient's diagnosis, age, weight and sex.

RESULTS

The median number of PBPC collected was 6.68 mononuclear cells (MNC)x10(8)/kg (range 2.36-19.05) and 1.69 CD34(+) cellsx10(6)/kg (range 0.08-13.79). Multivariate analysis showed that factors independently associated with the CD34(+) cell yield per apheresis were pre-apheresis CD34(+) cell count (P<0.001), diagnosis (P=0.008) and apheresis volume (P=0.009). Recruitment of CD34(+) cells was also independently affected by the apheresis volume, being higher in the LVL group (P=0.008).

DISCUSSION

We have demonstrated that, apart from the well-known influence of the pre-apheresis CD34(+) cell count, two other factors have a major impact on the CD34(+) cell yield: patient's diagnosis and apheresis volume. In addition, taking into account that side effects were mild and tolerable, we have confirmed that LVL is a safe and effective procedure in children </=25 kg, and that AutoPBSC software could be reliably used in these patients, provided that an experienced team performs the procedure.

Effects of leukapheresis protocol, cell processing and cryopreservation on the generation of monocyte-derived DC for immune therapy

BACKGROUND

Many clinical trials of DC-based immunotherapy involve administration of monocyte-derived DCs (Mo-DC) on multiple occasion. We aimed to determine tbe optimal cell processing procedures and timing (leukapheresis, RBC depletion and cryopreservation) for generation of Mo-DC for clinical purposes.

METHODS

Leukapheresis was undertaken using a COBE Spectra. Two instrument settings were compared - the standard semi-automated software (Version 4.7) (n = 10) and the fully automated software (Version 6.0) (N = 40). Density gradient centrifugation using Ficoll, Percoll, a combination of these methods or neither for RBC depletion were compared. Outcomes (including cell yield and purity) were compared for cryopreserved unmanipulated monocytes and cryopreserved Mo-DC.

RESULTS

Software Version 6.0 provided significantly better enrichment for monocytes (P < 0.05) but 25% fewer total monocytes. Final Mo-DC purity was not influenced by leukapheresis or RBC depletion method, but was critically dependent on monocyte adherence. Version 6.0 produced significantly lower RBC and platelet contamination (P < 0.0005) but in vitro RBC depletion could not routinely be omitted. Only 5-6% of monocytes harvested resulted in Mo-DC (95% lost in cell processing or failing to differentiate).

DISCUSSION

Cell losses remained significant despite attempts to minimise processing steps during Mo-DC generation. Reduction in RBC and platelets achieved with software version 6.0 was insufficient to offset the disadvantage of the lower monocyte yield. Substantial savings in materials and other costs can be achieved if Mo-DC for multiple treatments are generated from cryopreserved monocytes rather than from fresh monocytes.

Mathematical model of peripheral blood stem cell harvest kinetics

A mathematical model of peripheral blood stem cell harvests was developed, taking two new parameters R (number of recruited cells/minute) and E(f) (efficiency of collection) into consideration in addition to concentrations and collected amounts of cells. This model was tested on 241 harvest procedures in cancer patients (chemotherapy+G-CSF stimulation), donors of allogeneic PBSC, and platelet donors, using different collection procedures, with a Cobe Spectra Cell separator. The relationships between preapheresis concentrations, R, E(f) and harvested amounts of cells were complex, and different for different harvest procedures and populations of donors. However, invariably, recruitment played an important role and contributed significantly to the final harvest in all types of cells studied. For example, for the patient group, mean recruitment was 1.3 x 10(6) CD34+ cells/min and the amount of recruited cells corresponded to 65% of all collected cells. Recruitment was significantly influenced by pretreatment with chemo-therapy and/or radiotherapy. The mean recruitment values for the subgroups with limited, moderate, and extensive pretreatment were 1.65 x 10(6), 0.87 x 10(6), and 0.32 x 10(6) CD34+ cells released per minute, respectively. The finding of a quick and massive recruitment phenomenon may stimulate further research into hematopoiesis in order to maximize harvested cells.

Mononuclear cell collection in patients undergoing extra-corporeal photo-chemotherapy for acute and chronic graft-vs.-host-disease (GvHD): comparison between COBE Spectra version 4.7 and 6.0 (AutoPBSC)

A constant improvement in the performance of blood cell separators has been observed in recent years, allowing better yields in peripheral blood stem cell collection (PBSC) either from healthy donors or for autologous purposes. Nevertheless, to our knowledge, no reports on the efficiency of mononuclear cell (MNC) collection in patients undergoing extra-corporeal photochemotherapy (ECP) for graft-vs.-host-disease (GvHD) have been published. We retrospectively investigated the efficiency of 167 MNC collections performed consecutively in 12 patients between January 1999 and June 2001 by means of the COBE Spectra version 4.7 (V 4.7) or version 6.0 (V 6.0), for 109 and 58 procedures, respectively. MNC fractional extraction (FE) was higher in the V 6.0 group compared to the V 4.7 group : 0.59 +/- 0.21 vs. 0.51 +/- 0.22 (P < 0.05). However, platelet contamination was lower in the products obtained with V.6.0 compared to those obtained with V.4.7: 740 ( 630 x 10(3)/(L vs. 2,073 ( 1,429 x 10(3)/(L (P < 0.05). Only two patients with acute GvHD, both from V 4.7 group, required post-ECP platelet transfusion. The recently released version 6.0 allowed a satisfactory MNC yield with minimal platelet contamination in patients scheduled to undergo ECP for acute or chronic GvHD.

CD34(+) cell collection efficiency does not correlate with the pre-leukapheresis hematocrit

One hundred and seventy-seven large-volume leukapheresis procedures performed on 91 patients over a 15 month period were reviewed to see if the pre-apheresis hematocrit (Hct) affected the CD34(+) cell collection efficiency (CE) of the Fenwal CS 3000 Plus cell separator. The Hct was 0.174-0.461 (median 0.317), and the peripheral blood CD34(+) cell count 2-2487 per microl (median 21). The total CD34(+) cell quantity collected was 3.0-2677.2 x 10(6) (median 113.0). Based on the number of CD34(+)cells contained in the blood volume processed (23.3-37303.2 x 10(6); median 318.0), the CE was 1.7-87.5% (median 30.3). No correlation was found between the Hct and CE (r(2) = 0.0034; P = 0.44) or the total CD34(+) cell quantity collected (r2 = 0.0040; P = 0.40). CEs for Hct <0.25 (median CE 36%), Hct 0.25-0.299 (median CE 30%) and Hct 0.30 (median CE 30%) were comparable. As expected, highly significant correlations were seen between the CD34(+) cell quantities collected and quantities processed (r2 = 0.59; P < 10(-6)) as well as the peripheral blood CD34(+) cell counts (r2= 0.60; P < 10(-6)). We conclude that the minimum acceptable Hct or hemoglobin level for leukapheresis should be dictated by clinical circumstances because it does not affect stem cell collection.

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.

Docetaxel effectively mobilizes peripheral blood CD34+ cells

We prospectively evaluated docetaxel (100 mg/m2) with G-CSF (10 microg/kg S.C., daily) for mobilization efficiency in 26 patients with breast cancer. The minimum target yield was >4.5 x 10(6) CD34+ cells/kg (optimum = 9 x 10(6)/kg), sufficient to support the subsequent three cycles of high-dose therapy (HDT). The peak days for peripheral blood (PB) CD34+ cells were day 8 and day 9. Seven collections began on day 7, 16 on day 8 and three on day 9. The median peripheral blood progenitor cell (PBPC) CD34+ cell content ranged from 1.2 to 5.9 x 10(6)/kg per day during days 7 to 11 with a median CD34+ content of the total 72 PBPC collections of 3.4 x 10(6)/kg (0.07-15.6). Fifteen patients obtained a PBPC collection exceeding 5 x 10(6)/kg on a single day of collection. Following a median 3 days collection for each patient (range 2-4), the median total CD34+ for all individual sets of collections was 9.7 x 10(6)/kg (range 1.0-28.4). We were able to achieve the minimum CD34+ cell target yield in 22 of 26 patients with one cycle of mobilisation chemotherapy and in two of these patients a second collection yielded sufficient cells. Twenty-two patients have subsequently received repetitive HDT and PBPC transplantation with 57 cycles of HDT having been delivered. For all 57 cycles, the median time to absolute neutrophil count (ANC) >0.5 x 10(9)/l and 1.0 x 10(9)/l was 10 days (range 8-22) and 11 days (range 8-23), respectively. The median time to platelets greater than 20 x 10(9)/l, 50 x 10(9)/l and 100 x 10(9)/l was 13 days (range 11-23), 17 days (range 12-53) and 23 days (range 18-70), respectively. We conclude that docetaxel with G-CSF effectively mobilises PBPCs with apheresis needing to be commenced approximately 8 days after docetaxel administration.

In vitro collection and posttransfusion engraftment characteristics of MNCs obtained by using a new separator for autologous PBPC transplantation

BACKGROUND

A clinical study was performed to evaluate the peripheral blood progenitor cell (PBPC) collection, transfusion, and engraftment characteristics associated with use of a blood cell separator (Amicus, Baxter Healthcare).

STUDY DESIGN AND METHODS

Oncology patients (n = 31) scheduled for an autologous PBPC transplant following myeloablative therapy were studied. PBPCs were mobilized by a variety of chemotherapeutic regimens and the use of G-CSF. As no prior studies evaluated whether PBPCs collected on the Amicus separator would be viable after transfusion, to ensure patient safety, PBPCs were first collected on another cell separator (CS-3000 Plus, Baxter) and stored as backup. The day after the CS-3000 Plus collections were completed, PBPC collections intended for transfusion were performed using the Amicus instrument. For each transplant, >2.5 x 10(6) CD34+ PBPCs per kg of body weight were transfused.

RESULTS

Clinical data collected on the donors immediately before and after PBPC collection with the Amicus device were comparable to donor data similarly obtained for the CS-3000 Plus collections. While the number of CD34+ cells and the RBC volume in the collected products were equivalent for the two devices, the platelet content of the Amicus collections was significantly lower than that of the CS-3000 Plus collections (4.35 x 10(10) platelets/bag vs. 6.61 x 10(10) platelets/bag, p<0.05). Collection efficiencies for CD34+ cells were 64 +/- 23 percent for the Amicus device and 43 +/- 14 percent for the CS-3000 Plus device (p<0.05). The mean time to engraftment for cells collected via the Amicus device was 8.7 +/- 0.7 days for >500 PMNs per microL and 9.7 +/- 1.5 days to attain a platelet count of >20,000 per microL-equivalent to data in the literature. No CS-3000 Plus backup cells were transfused and no serious adverse events attributable to the Amicus device were encountered.

CONCLUSIONS

The mean Amicus CD34+ cell collection efficiency was better (p<0.05) than that of the CS-3000 Plus collection. Short-term engraftment was durable. The PBPCs collected with the Amicus separator are safe and effective for use for autologous transplant patients requiring PBPC rescue from high-dose myeloablative chemotherapy.