A comparison of peripheral blood stem cell apheresis using the Fenwal CS3000 Plus and COBE Spectra

Large Volume Leukapheresis for Collecting Hemopoietic Progenitors: Role of CD 34+ Precount in Predicting Successful Collection

In this work we evaluated the efficacy of stem cell collection with Large Volume Procedures. (LVP), and analysed the importance of the CD34+ cell precount in promoting the collection of a sufficient number of CD34+ cells for transplantation, using the Univariate Logistic Regression analysis. Eighty-nine leukapheresis were performed in 49 patients with hematological malignancies and solid tumors, mobilized with chemotherapy plus Granulocyte Colony Stimulating Factor (G-CSF). For each procedure 15.8 liters of blood were processed. The median value of Nucleated Cells (NC) and CD34+ cells precount was respectively 8.29 × 109/ml (range 1.13÷45.4) and 43.08 × 103/ml (range 1.06÷795.2). Results show the capability of LVP to collect large quantities of hemopoietic progenitors with a median CD34+ cell total yield of 215.02 × 106 (range 5.03÷2210). The yields per patients’ body weight were: CD34+ cells 3.23 × 106/kg (range 0.081÷41.58). The regression analysis between blood cell precounts and collection yields gave the following correlations: the CD34+ cell precount correlates with CD34+ yield (r = 0.78 p < 0.00) and with CD34+ cell yield/kg (r = 0.76 p < 0.00). The number of CD34+ cells processed correlated with the number of CD34+ cells collected/kg (r = 0.83 p < 0.000). To investigate the importance of CD 34+ cell precount in promoting CD34+ cell yields ≥2.5 × 106/kg we performed a Univariate Logistic Regression analysis that showed in our patients a probability of collecting ≥2.5 × 106 CD34+/kg that rose from 0.6 to 0.95 for CD 34+ precounts that oscillated from 30 to 40 × 103 CD34+ cells/ml, respectively. The Univariate Logistic Regression gave a probability of collecting ≥2.5 × 106 CD34+ cells/kg that oscillated between 0.64÷0.98 for values of CD34+ cells processed from 6 × 106/kg to 8 × 106/kg, p <0.000. Sixty-three percent of patients reached the target dose of 2.5 × 106 CD34+ cells/kg with only one LVP. Until now 12 patients have been transplanted and all have had a prompt and complete lasting recovery. These results confirm the efficacy of LVP in harvesting hemopoietic progenitors and their ability in reconstituting hemopoiesis of transplanted patients, enabling the estimation of CD34+ precounts and CD34+ cells processed values, highly predictive for the collection of ≥2.5 × 106 CD34+ cells/kg. Furthermore, the Logistic Model suggests that the best strategy to plan a successful CD34+ cell collection procedure is to identify for each patient the amount of CD34+ cells/kg to be processed rather than the fixed processing of 3÷5 blood volumes in all patients.

The Application of Two Different Blood Cell Separators to Harvest CD34+ Cells in Patients Suffering from Non Hodgkin's Lymphoma

From January 1996 until now, thirty-eight PBSC procedures were carried out on 20 patients suffering from NHL, mobilized by polichemotherapy regimens plus recombinant human Granulocyte-Growth Factor (rhG-CSF). Patients were enrolled in PBSC procedures using Dideco Excel (group A) and Cobe Spectra v.4.7 (group B) blood cell separators. Twelve patients were enrolled in group A (6 males and 6 females, median age 33) and 9 patients in group B (5 males and 4 females, median age 55). The mean White Blood Cell (WBC) and Mononuclear Cells Fraction (MNC) peripheral blood counts were not statistically different in either group and neither were blood CD34+ cell peripheral counts. CD34+ cell peripheral value was predictive of the CD34+ yield while mean values of harvested CD34+ cells were not significantly different. CD34+ cell efficiences were statistically the same. The CD34+ cell purity of the apheresis harvest was statistically different between the two groups (group A = 3.0 ± 2.2%; group B = 1 ± 0.9%) p = 0.001. High CD34+ cell yields were observed in both groups which confirms that both blood cell separators are able to harvest hematopoietic progenitor cells from peripheral blood.

Intraoperative stem cell therapy

Stem cells hold significant promise for regeneration of tissue defects and disease-modifying therapies. Although numerous promising stem cell approaches are advancing in clinical trials, intraoperative stem cell therapies offer more immediate hope by integrating an autologous cell source with a well-established surgical intervention in a single procedure. Herein, the major developments in intraoperative stem cell approaches, from in vivo models to clinical studies, are reviewed, and the potential regenerative mechanisms and the roles of different cell populations in the regeneration process are discussed. Although intraoperative stem cell therapies have been shown to be safe and effective for several indications, there are still critical challenges to be tackled prior to adoption into the standard surgical armamentarium.

Evaluation of the COM.TEC cell separator in predicting the yield of harvested CD34+ cells

BACKGROUND

This multicenter study was performed with the intention to evaluate the exactness of the predicted CD34+ cell yield calculated by two leukapheresis programs of the cell separator COM.TEC upon the number of donor's circulating CD34+ cells and the blood volume processed.

STUDY DESIGN AND METHODS

Patients and healthy donors (n = 166) received mobilization by chemotherapy and/or granulocyte colony-stimulating factor and underwent CD34+ cell harvest by the leukapheresis programs MNC or RV-PBSC (n = 203).

RESULTS

CD34+ cells were collected by 112 harvests on MNC and by 91 collections on RV-PBSC. The median collection efficiency of CD34+ cells was significantly better for the program MNC than for RV-PBSC (p < 0.001): 67% (31-109) vs. 42% (19-100). The collected CD34+ cell yield was in median more exactly by MNC than by RV-PBSC (p < 0.001): 85% (31-176) vs. 59% (22-110) of the predicted value. Concentrates obtained by RV-PBSC showed in median significantly higher percentages of mononuclear cells (p < 0.001) and CD34+ cells (p < 0.001), 86% (43-99) vs. 56% (25-95) and 1.2% (0.2-14.3) vs. 0.4% (0.1-6.0), and had lower contaminations by erythrocytes (p < 0.001) and platelets (p < 0.001), 13 mL (4-48) vs. 25 mL (5-60) and 1.9 x 1011 vs. 3.1 x 1011, than those harvested by MNC.

CONCLUSION

The significantly better collection efficiency of CD34+ cells and the more exact prediction of the harvested CD34+ cell yield make the leukapheresis program MNC a safe and efficient procedure. However, concentrates collected by RV-PBSC are of a better cellular quality with a significantly higher percentage of mononuclear and CD34+ cells and a lower contamination by erythrocytes and platelets.

Apheresis techniques for collection of peripheral blood progenitor cells

The combination of effective mobilisation protocols and efficient use of apheresis machines has caused peripheral blood progenitor cells (PBPC) transplantation to grow rapidly. The development of apheresis technology has improved over the years. Today PBSC procedures have changed towards systems to minimise operator interaction and to reduce the collection of undesired cells such as polymorphonuclear cells and platelets using functionally closed, sterile environments for PBSC collection in keeping with Good Manufacturing Practice guidelines. Blood cell separators with continuous flow technique allow the processing of more blood than intermittent flow devices resulting in higher PBSC yields. Large volume leukapheresis with the processing of 3-4-fold donor's/patient's blood volume can increase the number of collected progenitor cells. Therefore, intermittent flow cell separators are indicated if only single vein access is available. Anticoagulant induced hypocalcaemia is an often observed side effect in long lasting PBPC harvesting and monitoring of electrolytes should be performed especially at the end of the apheresis procedure to supplement low levels of potassium, calcium or magnesium. Refinement and improvement of collection techniques continue to add to the armamentarium of current approaches for cancer and non-malignant conditions and will enable future strategies.

Comparison of two leukapheresis programs for computerized collection of blood progenitor cells on a new cell separator

BACKGROUND

Peripheral blood progenitor cells (PBPCs) can be collected on various cell separators. Two leukapheresis programs (LP-MNC and LP-PBSC-Lym) were evaluated for computerized collection of PBPCs on a new cell separator.

STUDY DESIGN AND METHODS

Leukapheresis assisted by the LP-MNC or LP-PBSC-Lym software was performed for the harvesting of PBPCs in 52 oncology patients after chemotherapy plus G-CSF treatment and in 18 healthy subjects after G-CSF mobilization alone.

RESULTS

A total of 38 components from 33 donors via LP-MNC and 43 components from 37 donors via LP-PBSC-Lym were collected with a median of one (range, one to two) standard-volume leukapheresis procedures (9.2-13.3 L) per donor. There were no significant differences between the two groups concerning median counts of WBCs, CD34+ cells, CD34+ cell yields per harvest, and CD34+ cell yields of cumulative harvests. The blood cell counts after leukapheresis revealed that the LP-MNC resulted in significantly higher platelet loss than LP-PBSC-Lym (p = 0.024): 35.9 percent (range, 19.2%-66.1%) versus 29.7 percent (11.6%-52.3%). Regarding the CD34+ cell collection efficiency, the LP-MNC program was significantly better than the LP-PBSC-Lym program (p < 0.001): 77.5 percent (range, 35.5%-98.9%) versus 58.3 percent (range, 20.4%-98.9%). However, concentrates collected by the LP-PBSC-Lym program had significantly higher percentages of MNCs (p < 0.001) and CD34+ cells (p = 0.028) than harvests with the LP-MNC program: 90 percent (range, 69%-99%) versus 70 percent (range, 35%-98%) and 1.2 percent (range, 0.2%-7.3%) versus 0.7 percent (range, 0.2%-6.0%), respectively. No leukapheresis-related serious adverse events were seen, and time for hematopoietic engraftment was equivalent to data published in the literature.

CONCLUSION

The LP-MNC program shows a significantly better CD34+ cell collection efficiency than the LP-PBSC-Lym program. However, collections with the LP-MNC program result in PBPC components with a lower MNC and CD34+ cell concentrations and a higher apheresis-related loss of patient's platelets.

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.

Stem Cell Collection using the Dideco Excel Continuous Flow Blood Cell Separator: Parameters for Optimal Stem Cell Collection Timing

This study evaluates stem cell collection procedures performed with the Dideco Excel blood cell separator, with particular attention given to yields and separator collection efficiencies. Patients’ blood precounts and yield parameters related to the harvest capacity of the collection system were investigated. Fifty-five collection procedures were analyzed in 32 patients suffering from hematological malignancies and solid tumors and mobilized with chemotherapy plus G-CSF. The median blood volume processed in each procedure was 15.8 liters (12–19.750), with a blood flow rate of 70 ml/min. Patients had the following median blood precount value: NC 7.81×109/L, CD34+ cells 49.08×103/ml. Leukapheresis procedures gave the following yields: NC 14.95×109, MNC 10.83×109, CD34+ cells 4.37×106; yields/kg, NC 0.21×109kg, MNC 0.15×109/kg CD34+ cells 4.26×106/kg. Procedures show the following collection efficiencies: NC 10.79%, MNC 29.06%, CD34+ 42.33%, PLT 26.5%. The RBC (red blood cell) contamination of the product was (median value) 20.9 ml for each procedure, and for platelets 1.76×1011 per procedure. The CD34+ cell precounts strongly correlated with the CD34+ yields/kg (r=0.82. p=0.000). Furthermore the NC and MNC precounts correlated with the CD34+ yields/kg but only the MNC precount correlation is notable (r=0.57, p=0.000). The logistic regression analysis shows that CD34+ (p=0.008) but not NC (po=0.14), MNC (p=0.09), or PLT (p=0.53) precounts significantly influenced the collection of a sufficient dose of CD34+ cells for transplantation (≥ 2.5×106/kg). Eleven of the thirty-two patients have been transplanted till now, and all had a prompt and lasting trilineage engraftment NC >1×109/L on day 12 (10–17). Our data show that the collection system analyzed in this report is able to collect large amounts of progenitor cells, harvesting ≥2.5×106/kg CD34+ cells with a single procedure in 68.8% of patients and assuring complete recovery after stem cell transplantation.

Evaluation of a new protocol for peripheral blood stem cell collection with the Fresenius AS 104 cell separator

In this report we analyzed sixty leukapheresis procedures on 35 patients with a new protocol for the Fresenius AS 104. Yields and efficiencies for MNC, CD 34+ cells, and CFU-GM indicate that the new protocol is able to collect large quantities of hemopoietic progenitors. Procedures were performed processing 8.69 +/- 2.8 liters of whole blood per apheresis and modifying 3 parameters: spillover-volume 7 ml, buffy-coat volume 11.5 ml, centrifuge speed 1,500 rpm; blood flow rate was 50 ml/min and the anticoagulant ratio was 1:12. No side effects were observed during apheresis procedures except for transient paresthesia episodes promptly resolved with the administration of calcium gluconate. Yields show a high capacity of the new program to collect on average MNC 17.28 +/- 10.85 x 10(9), CD 34+ 471 +/- 553.5 x 10(6) and CFU-GM 1278.7 +/- 1346.3 x 10(4) per procedure. Separator collection efficiency on average was 49.91 +/- 23.28% for MNC, 55.1 +/- 35.66% for CFU-GM, and 62.97 +/- 23.09% for CD 34+ cells. Particularly interesting are results for MNC yields and CD 34+ efficiency; these results make the new program advantageous or similar to the most progressive blood cell separators and capable to collect a sufficient number of progenitor cells for a graft with a mean of 1.80 +/- 0.98 procedures per patient.

Improved collection of mobilized CD34+ hematopoietic progenitor cells by a novel automated leukapheresis system

BACKGROUND

For simplification of blood cell transplantation, an automated apheresis system that exploits a dual-stage channel device for mononuclear cell (MNC) collection (AutoPBSC, designed for the COBE Spectra) was studied.

STUDY DESIGN AND METHODS

The automated default software (AutoPBSC-Default) and three software modifications of the harvest frequency during leukapheresis, referred to as AutoPBSC-1.25, AutoPBSC-1.75, and AutoPBSC-2.75, were evaluated in comparison with the semiautomated Version 4.7 (V4.7) apheresis system in 119 leukapheresis procedures performed in 90 cancer patients treated with chemotherapy plus granulocyte-colony-stimulating factor. CD34+ cell and platelet collection efficiency (CE); volume and cell composition of the leukapheresis components; and patient platelet and red cell (RBC) loss during leukapheresis were measured.

RESULTS

The majority of collection measures evaluated with the AutoPBSC compared favorably to those obtained with the V4.7. CD34+ cell CE increased from 55 percent with V4.7 to 68 percent with the AutoPBSC-Default (p = 0.05). The AutoPBSC provided lower platelet contamination in the collected component (1.18 x 10(11) vs. 2.26 x 10(11) with the V4.7; p<0.001). The volume of the AutoPBSC-Default component was significantly lower (67 vs. 180 mL with the V4.7; p<0.001). The MNC purity of the AutoPBSC component was greater (52 vs. 28% with the V4.7; p<0.001), and the RBC contamination lower (AutoPBSC, 0.53 x 10(11) vs. 1.04 x 10(11) with the V4.7; p<0.001). Modifications of the AutoPBSC to increase the harvest frequency by 1.25-, 1.75-, and 2.75-fold resulted in increased CD34+ cell CE (77%, 75%, and 83%, respectively; p<0.001 in all cases), but also in reduced numbers of circulating platelets, higher platelet contamination of the component, and lower MNC purity than were seen with the AutoPBSC-Default.

CONCLUSION

The AutoPBSC offers the following advantages over the V4.7 system: a) better CE of CD34+ cells; b) reduced collection of platelets; c) reduced contamination of the leukapheresis component with granulocytes, platelets, and RBCs; d) reduced component volume; and e) automation.

Sources and sequelae of bacterial contamination of hematopoietic stem cell components: implications for the safety of hematotherapy and graft engineering

BACKGROUND

It is important to compare the incidence of bacterial contamination of components collected from the peripheral blood or bone marrow (BM), as well as of components processed with or without cell selection or depletion, and to evaluate the sequelae of such contamination.

STUDY DESIGN AND METHODS

Bacterial contamination rates were compared in 1380 untreated autologous peripheral blood progenitor cells (PBPCs), 291 untreated autologous BM samples, 916 monoclonal antibody (MoAb)-treated autologous and allogeneic BM samples, and in 45 autologous PBPC components from which the CD34+ cells were selected. Bacterial cultures were performed at sequential time points during the processing of MoAb-treated BM.

RESULTS

Bacterial contamination was documented in 44 of 2632 components from 1593 patients (1.67% of components, 2.76% of patients) before cryopreservation. Although only 0.65% of untreated PBPCs were contaminated before cryopreservation, each patient was more likely to have given a contaminated PBPC component than a contaminated BM component (2.41% vs. 0%, p < 0.01). Bacterial contamination of MoAb-treated BM was greater during or after manipulation than it was before (2.33% vs. 0.77%, p < 0.05). At thawing, contamination was documented in 42 (1.97%) of 2136 components cultured. Ten (13.7%) of 73 patients who received hematopoietic progenitor cells that were contaminated before cryopreservation or at thawing developed fever or positive blood cultures within 48 hours of transfusion. Fever was associated with bacteremia in two cases, but no irreversible clinical sequelae were noted.

CONCLUSION

These studies suggest that, despite careful attention to sterile procedures, low-level contamination of hematopoietic stem cell components can be introduced before or during manipulation as well as at thawing, and that standards for monitoring of the procedures for collection, processing, cryopreservation, thawing, and transfusion of hematopoietic progenitor cells are necessary.

Autologous peripheral blood progenitor cell transplantation

Harvesting of autologous peripheral blood stem cells (PBSCs) has been facilitated by using currently available, efficient apheresis technology at the time of rebound from chemotherapy while patients are receiving recombinant growth factors, i.e., granulocyte (G) or granulocyte-macrophage (GM) colony stimulating factor (CSF). Ideally pheresis should be done before patients have had extensive stem cell toxins, i.e., alkylating agents or nitrosoureas. This strategy has facilitated the use of high dose chemoradiotherapy given as a single regimen or in a divided dose for patients with solid tumors or hematologic malignancies and results in more rapid engraftment than bone marrow transplantation (BMT). Although there are no assays which measure repopulating stem cells, enumeration of CD34+ cells within PBSCs is a direct and rapid assay which provides an index of both early and late long-term reconstitutive capacity, since it correlates with colony-forming unit (CFU)-GMs, as well as pre-progenitor or delta assays and long-term culture-initiating cells (LTC-IC). A threshold of > or = 2 x 10(6) CD34+ cells/kg recipient body weight has been reported to be required for engraftment, but may vary depending upon the clinical setting. Strategies for mobilization of normal PBSCs also increase tumor cell contamination within PB in the setting of both hematologic malignancies and solid tumors, but the significance of these tumor cells in terms of patient outcome is unclear. Recently isolation of CD34+ cells from PBSCs has been done using magnetic beads or immunoabsorption on columns or rigid plates in order to enrich for normal hematopoietic progenitors and potentially decrease tumor cell contamination. As for other cellular blood components, standards have been developed to assure efficient collection and processing, thawing, and reinfusion, and to maintain optimal PBPC viability. Finally, future directions of clinical research include expansion of hematopoietic progenitor cells ex vivo; use of umbilical cord or placenta as rich sources of progenitor cells; syngeneic hematopoietic stem cell transplantation; related and unrelated allogeneic hematopoietic stem cell transplantation; treatment of infections, i.e., Epstein Barr virus, or tumor relapse after allogeneic BMT using donor PBSC infusions; and gene therapy approaches.