Cryopreservation of hematopoietic progenitor cells from apheresis at high cell concentrations does not impair the hematopoietic recovery after transplantation

BACKGROUND: The high number of nuclear cells (NCs) from hematopoietic progenitor cells-apheresis (HPC-A) requires cryopreservation in large volumes or at high NC concentrations. The effect of NC concentration during cryopreservation has yet to be examined. STUDY DESIGN AND METHODS: In the experimental arm (n = 610, Protocol B), the first HPC-A sample from the patient was cryopreserved in two cryobags and subsequent collections in one cryobag, resulting in high NC concentrations (>100 x 10(6) NCs/mL) in most cases. The effect of NC concentrations at freezing in NC recovery after thawing and engraftment kinetics was analyzed and compared with a group of HPC-A cryopreserved at standard NC concentrations (n = 455, Protocol A). RESULTS: The mean (SD) NC concentration at freezing was 78 (28) x 10(6) per mL (median, 82 x 10(6)/mL; range, 12 x 10(6)-156 x 10(6)/mL) and 183 (108) x 10(6) per mL (median, 156 x 10(6)/mL; range, 16 x 10(6)-678 x 10(6)/mL), for HPC-A cryopreserved according to Protocols A and B, respectively. The NC viabilities of the test vials and HPC-A components after thawing were 88 percent versus 85 percent and 85 percent versus 82 percent, and the cloning efficiency was 49 percent versus 33 percent for Protocols A and B, respectively (p < 0.001). Significant differences were not observed in the recovery of NCs. Days to neutrophil and platelet engraftment were not different between patients transplanted in the standard- (n = 143) or high-cell-concentration group (n = 238). CONCLUSION: The cryopreservation of HPC-A at higher than standard NC concentrations has no adverse impact on hematopoietic reconstitution after transplantation.     

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 mere 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 ≥2 × 10⁶ 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.     

Engraftment after autologous hematopoietic stem cell transplantation in patients mobilized with Plerixafor: A retrospective,multicenter study of a large series of patients

Plerixafor (PLX) appears to effectively enhance hematopoietic stem-cell mobilization prior to autologous hematopoietic stem cell transplantation (auto-HCT). However, the quality of engraftment following auto-HCT has been little explored. Here, engraftment following auto-HCT was assessed in patients mobilized with PLX through a retrospective, multicenter study of 285 consecutive patients. Information on early and 100-day post-transplant engraftment was gathered from the 245 patients that underwent auto-HCT. The median number of PLX days to reach the stem cell collection goal (≥2 × 10⁶ CD34⁺ cells/kg) was 1 (range 1–4) and the median PLX administration time before apheresis was 11 h (range 1–18). The median number of apheresis sessions to achieve the collection goal was 2 (range 1–5) and the mean number of CD34⁺ cells collected was 2.95 × 10⁶/kg (range 0–30.5). PLX administration was safe, with only 2 mild and transient gastrointestinal adverse events reported. The median time to achieve an absolute neutrophil count (ANC) >500/μL was 11 days (range 3–31) and the median time to platelet recovery >20 × 10³/μL was 13 days (range 5–69). At 100 days after auto-HCT, the platelet count was 137 × 10⁹/L (range 7–340), the ANC was 2.3 × 10⁹/L (range 0.1–13.0), and the hemoglobin concentration was 123 g/L (range 79–165). PLX use allowed auto-HCT to be performed in a high percentage of poorly mobilized patients, resulting in optimal medium-term engraftment in the majority of patients in whom mobilization failed, in this case mainly due to suboptimal peripheral blood CD34⁺ cell concentration on day +4 or low CD34⁺ cell yield on apheresis.     

Cryopreservation of peripheral blood stem cell: the influence of cell concentration on cellular and hematopoietic recovery

BACKGROUND: The optimal cryopreservation cell concentration during the peripheral blood stem cell (PBSC) collection is a controversial topic. We evaluated the influence of cryopreservation concentration on the recovery of hematopoietic progenitor cells and the kinetics of hematopoietic recovery of autologous stem cell transplant patients. STUDY DESIGN AND METHODS: In this retrospective study, we compared two different cryopreservation protocols: 1 × 10⁸ cells/mL (Protocol A) and 2 × 10⁸ cells/mL (Protocol B). A total of 419 PBSCs were analyzed with regard to the number of viable cells and colony‐forming units–granulocytes‐monocytes (CFU‐GM) progenitors. The hematopoietic recovery of 275 patients who received PBSCs cryopreserved at a dose of 1 × 10⁸ cells/mL (Group A) and 2 × 10⁸ cells/mL (Group B) were compared. RESULTS: There were no significant differences in recovery of viable cells between Protocol A and Protocol B. The median of recovery of CFU‐GM progenitors was significantly higher in Protocol B (41.2 vs. 57.3, p < 0.01). The median times to neutrophil recovery (≥500 × 10⁶/L) and platelet (PLT) recovery (≥20 × 10⁹/L) in Groups A and B were 11 days versus 11 days and 12 days versus 12 days, respectively. However, by Kaplan and Meier analyses, Group B recovered neutrophils with a little delay (p = 0.01). No difference was observed with regard to time to PLT recovery. On multivariate analysis, we found that the number of CD34+ cells and CFU‐GM progenitors had a significant influence on hematopoietic recovery. CONCLUSION: Cryopreservation of PBSCs at a dose of 2 × 10⁸ cells/mL did not affect the recovery rate of viable cells or the hematopoietic recovery of autologous stem cell transplant patients.     

A prospective clinical trial evaluating the safety and efficacy of the combination of rituximab and plerixafor as a mobilization regimen for patients with lymphoma

BACKGROUND: Previous reports suggested that rituximab may impair stem cell collection and posttransplant engraftment in lymphoma patients undergoing autologous hematopoietic progenitor cell transplantation. STUDY DESIGN AND METHODS: A prospective biologic allocation study examined the effect of adding rituximab to a mobilization regimen of plerixafor and granulocyte–colony‐stimulating factor (G‐CSF) for patients with CD20+ lymphoma compared with CD20? lymphoma patients mobilized without rituximab. The primary endpoint was safety of the rituximab‐containing regimen; secondary endpoints compared the efficiency of stem cell collection, posttransplant engraftment, graft characteristics, mobilization kinetics, immune reconstitution, and engraftment durability between the cohorts of patients with CD20+ and CD20? lymphoma. RESULTS: Fifteen subjects assigned to each treatment arm were accrued. Both mobilization regimens had similar toxicities. The median number of CD34+ cells collected (7.4 × 10⁶/kg vs. 6.4 × 10⁶/kg) and the median numbers of days of apheresis needed to collect stem cells were not different between the CD20+ and CD20? cohorts. No significant differences in neutrophil engraftment (median, 13.5 days vs. 13 days) or platelet engraftment (22 vs. 21 days) or in graft durability were seen comparing patients with CD20+ versus CD20? lymphoma. There were no significant differences in the kinetics of blood T‐cell or natural killer–cell reconstitution comparing the two groups. B‐cell reconstitution was delayed in the CD20+ lymphoma group, but this did not translate into a significant increase in infectious complications. CONCLUSION: Rituximab can be safely added to the combination of plerixafor and G‐CSF as a mobilization strategy without excess toxicity or posttransplant engraftment delays for patients with chemosensitive lymphoma undergoing autologous hematopoietic progenitor cell transplantation.     

Evaluation of hematological reconstitution potential of autologous peripheral blood progenitor cells cryopreserved by a simple controlled-rate freezing method

A novel and simple procedure for the controlled-rate cryopreservation of peripheral blood progenitor cells (PBPCs) was introduced. A freezing bag housed in a protective aluminum canister was placed on top of a styrene foam box in the -85 degrees C electric freezer. A second set of samples was kept in cryotubes placed in a double styrene foam box in the same electric freezer. Measurement of the freezing rate in the PB bags and cryotubes demonstrated that this simple method for PBPC cryopreservation provided optimal conditions for both large-scale and small-scale cryopreservation. Within several days after autologous peripheral blood stem cell transplantation, we thawed the cells in the small sample tubes and evaluated the cell viability, the cell recovery, and the recovery rates of hematopoietic progenitor cells (HPCs), such as CD34+ cells and colony-forming unit-granulocyte/macrophage (CFU-GM) colonies. The median duration of cryopreservation was 59 days (range, 14-365 days). According to our analysis, infusions of more than 2 x 10(6) CD34+ cells/kg body weight and 0.5 x 10(6) CFU-GM colonies/kg body weight after thawing had favorable influences on the neutrophil engraftment. We have therefore established a simple freezing method for cryopreservation of human PBPCs, which ensures the transplantability of hematopoietic progenitors even after thawing. In vitro HPC assay after thawing is important to evaluate the quality of cryopreservation procedures.     

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.     

Current status of art mobilization in Myeloma

Multiple myeloma is the leading indication of autologous hematopoietic cell transplantation (AHCT) worldwide. Hematopoietic progenitor cell mobilization (HPCM) is the first step of a successful AHCT. A minimum of 2 × 10⁶ CD34⁺ cells/kg are needed for successful engraftment. Growth factors have been used both alone or in combination with chemotherapy for HPCM of patients with myeloma. Mobilization failures result in delays in AHCT and increased cost and resource utility. Strategies to mobilize progenitor cells were mainly chemotherapy and growth factor or growth factor-only mobilization until the advent of plerixafor. Plerixafor is successfully integrated into both growth factor-only and cyclophosphamide and growth factor mobilization strategies with significantly reducing the mobilization failure rate in myeloma patients. The best strategy to mobilize progenitor cells with the highest yield and lowest toxicity and cost in patients with multiple myeloma has not yet been determined. This review aims to summarize the current status of art mobilization in myeloma comparing the pros and cons of different mobilization strategies.     

Impact of storage temperature and processing delays on cord blood quality: discrepancy between functional in vitro and in vivo assays

BACKGROUND: Optimal conditions of cord blood (CB) storage, processing, cryopreservation, and thawing are critical for banking and transplantation. Nevertheless, standardized procedures are still awaited. STUDY DESIGN AND METHODS: We evaluated the impact of preprocessing storage and temperature on recovery, viability, and functional differentiation capacities of hematopoietic progenitor cells. We compared units stored at room temperature (RT) or at 4°C for 72 hours before cryopreservation to units processed shortly after collection (<12 hr). RESULTS: Postthaw results showed similar in vitro characteristics between immediate processing and 4°C storage for cell recovery and viability, both significantly higher than RT storage. Surprisingly, we demonstrated that storage of CB units at RT before processing and cryopreservation profoundly altered in vivo hematopoietic reconstitution in mice, although in vitro hematopoietic colony‐forming unit potential was unaltered. CONCLUSION: Our findings challenge current CB storage practices and suggest standard in vitro quality assessments may not always be indicative of CB engraftment potential.     

Mobilization, collection, and transplantation of peripheral blood hematopoietic progenitor cells in a patient with multiple myeloma and hemoglobin SC disease

BACKGROUND: The use of granulocyte–colony‐stimulating factor (G‐CSF) for mobilization, collection, and transplantation of autologous hematopoietic progenitor cells (HPCs) in patients with hemoglobinopathies can be complicated by severe vasoocclusive crises. Erythrocytapheresis before G‐CSF administration may help prevent these complications. To date, no cases regarding the safety and outcome of erythrocytapheresis followed by autologous high‐dose G‐CSF mobilization in hemoglobinopathy populations have been reported. STUDY DESIGN AND METHODS: A patient with hemoglobin (Hb) SC disease and multiple myeloma underwent erythrocytapheresis followed by high‐dose (16 µg/kg) G‐CSF in preparation for HPC mobilization and collection. RESULTS: Erythrocytapheresis reduced the patient's combined Hb S and C levels to less than 20 percent. Subsequent HPC mobilization and peripheral blood harvesting using high‐dose G‐CSF yielded approximately 9 × 10⁶ CD34+ HPCs per kg over 3 days of collection. Mobilization and leukapheresis were completed without vasoocclusive complications. Two weeks after collection, and after myeloablative chemotherapy, 5.33 × 10⁶ CD34+ HPCs per kg were infused to the patient; platelet and white cell engraftment occurred, respectively, on Days +9 and +10 posttransplant. The patient experienced no vasoocclusive complications in the posttransplant period. CONCLUSIONS: The results of this case demonstrate that erythrocytapheresis before high‐dose G‐CSF HPC mobilization and collection appears to be an effective means for prevention of vasoocclusive crisis in patients with hemoglobinopathies undergoing autologous stem cell transplantation.     

Photodynamic treatment with mono-phenyl-tri-(N-methyl-4-pyridyl)-porphyrin for pathogen inactivation in cord blood stem cell products

BACKGROUND: Hematopoietic stem cell transplants and culture of hematopoietic progenitor cells require pathogen‐free conditions. The application of a method of pathogen inactivation in red blood cells using photodynamic treatment (PDT) was investigated for the decontamination of cord blood stem cell (CBSC) products. STUDY DESIGN AND METHODS: CBSC products, spiked with Gram‐positive and Gram‐negative bacteria, were treated with PDT using mono‐phenyl‐tri‐(N‐methyl‐4‐pyridyl)‐porphyrin (Tri‐P(4)) and red light. After PDT, in vitro and in vivo evaluation of the CBSC functions were performed. RESULTS: PDT of CBSC products resulted in the inactivation of the bacteria, with Staphylococcus aureus being the most resistant. Complete decontamination was achieved when CBSC products were contaminated with low titers of bacteria. PDT had no effect on white blood cell viability, the ex vivo expansion potential of the progenitor cells, and their capacity to differentiate to various hematopoietic cell lineages. However, PDT reduced the engraftment of human CBSCs in NOD/SCID mice, particularly affecting the B‐cell lineage engraftment. CONCLUSION: Pathogen inactivation of CBSC with Tri‐P(4)‐mediated PDT is feasible at contamination level up to 10 to 20 colony‐forming units per mL and can be considered when ex vivo expansion culture is anticipated. However, this treatment is not recommended for transplantation purposes at this time. Further investigations may elucidate why engraftment is diminished.     

Leukapheresis in non–cytokine‐stimulated donors with a new apheresis system: first‐time collection results and evaluation of subsequent cryopreservation

BACKGROUND: Adoptive cell therapy based on mononuclear cells (MNCs) became an important modality of cancer immunotherapy. Data about collection results and donor response of leukapheresis with the Spectra Optia v.5.0 (Terumo BCT) in nonmobilized donors are required. STUDY DESIGN AND METHODS: Twelve MNC collections were performed using the Spectra Optia v.5.0 in non–cytokine‐stimulated donors. Leukapheresis products and peripheral blood samples from donors were assayed for CD45+, CD34+, CD3+, and CD14+ cells by flow cytometry. Prefreeze and postthaw cell counts, cell viability, and numbers of colony‐forming units were assessed in cryobags and compared to data from cryovials. RESULTS: Leukapheresis yielded a mean of 5.26 × 10⁹ ± 2.2 × 10⁹ CD45+ cells, 1.5 × 10⁹ ± 0.77 × 10⁹ CD14+ monocytes, and 2.28 × 10⁹ ± 1.2 × 10⁹ CD3+ T cells by processing 6690 ± 930 mL of whole blood. A significant positive correlation between yield of CD3+ T cells and residual platelets (PLTs) and red blood cells (RBCs) was observed. This did not apply for CD34+ and CD14+ white blood cell subsets. Mean collection efficiencies for CD14+ monocytes and CD3+ T cells were 61.8 ± 17 and 37.2 ± 18%, respectively. Recovery of CD14+ cells after cryopreservation was 75.2 ± 8.2%, which was significantly lower than recovery of CD45+ cells (81.4 ± 5.5%; p = 0.01). CONCLUSION: This study of a small cohort demonstrates that the Spectra Optia v.5.0 is capable of collecting low product volumes with satisfactory MNC yields and low residual RBCs and PLTs in non–cytokine‐mobilized apheresis. Our data suggest that cryovials can serve as a representative surrogate for the primary product cryobag.     

Mobilization of hematopoietic progenitor cells from allogeneic healthy donors using a new biosimilar G‐CSF (Zarzio®)

Peripheral blood progenitor cells (PBPCs) have become the major source of hematopoietic progenitor cells for allogeneic transplantation. In February 2008, Zarzio® was approved by the European Medicine Agency for PBPCs mobilization, but this authorization was not based in trials analyzing safety and efficacy for PBPCs mobilization. Since August 2011, Zarzio® has been used at our institution for PBPCs mobilization. In total 36 healthy family donors underwent PBPCs mobilization, 18 with Neupogen® and 18 with Zarzio®. Donor characteristics were equivalent between groups, and no severe adverse effects were registered in the Zarzio® group. The number of CD34 cells collected/Kg recipient body weight was 6.7 × 10⁶ (3.8–11.1) in the Zarzio® group versus 8.4 × 10⁶ (5.6–16.6) in the Neupogen® group (P = 0.04). We collected the minimal target cell dose (2 × 10⁶/kg) in all donors from each group and no significant differences were found in the collection of the optimal cell dose (5 × 10⁶/kg) between groups, although 3/18 (16.6%) donors that received Zarzio® failed to mobilize the optimal cell dose compared with 0% in the Neupogen® group. A total of 35 patients proceeded to transplantation (17 in the Zarzio® and 18 in the Neupogen® groups, respectively). Platelet and neutrophil median time to engraftment was comparable between the two groups. Our retrospective study supports the conclusion that Zarzio® mobilization of PBPCs in healthy donors is safe but perhaps not as effective as the reference Neupogen. However, more prospective trials are required to definitively asses the safety and efficacy of G‐CSF biosimilars for PBPCs mobilization in healthy donors. J. Clin. Apheresis 31:48–52, 2016. © 2015 Wiley Periodicals, Inc.     

Effects of cell concentration,time of fresh storage,and cryopreservation on peripheral blood stem cells: PBSC fresh storage and cryopreservation

IntroductionPeripheral blood stem cells are widely used in autologous or allogeneic transplantation. The quality of the product directly impacts clinical outcomes, and the cell quality and/or functionality may be influenced by the storage conditions as time, temperature, total nucleated cells (TNC) concentration and cryopreservation requirement.ObjectiveTo verify the effects of time, cell concentration, and cryopreservation/thawing in the viability and functionality of stem cells for transplantation.MethodsWe evaluated TNC, CD45⁺ viable cells, CD34⁺ viable cells, and cell viability and functionality of 11 samples. Measurements were performed immediately and 24 h, 48 h, 72 h, and 96 h after sample collection at high and low TNC concentrations. The same parameters were also evaluated after cryopreservation and thawing of the samples.ResultDuration of storage and TNC concentration exhibited a negative effect on cell quality (CD45⁺ viable cells, CD34⁺ viable cells and functionality). Moreover, the association of these parameters increased the negative effect on graft quality. Cryopreservation and thawing also negatively affected the collected sample regarding viable CD34⁺ cells (recovery 66.2 %), viable CD45⁺ cells (recovery 56.8 %), and 7-AAD viability. No significant losses in viable CD45⁺/CD34⁺ cells and functionality were observed in the first 24 h in both TNC conditions.ConclusionThese results emphasize the importance to consider carefully the storage conditions until transplantation, measuring TNC/μL until 24 h after collection (diluting the product when TNC > 300 × 10³/μL) and infusing fresh graft as soon as possible.     

CD41+ and CD42+ hematopoietic progenitor cells may predict platelet engraftment after allogeneic peripheral blood stem cell transplantation

The objective of this study was to quantify subpopulations of CD34+ cells such as CD41+ and CD42+ cells that might represent megakaryocyte (MK) precursors in peripheral blood stem cell (PBSC) collections of normal, recombinant human granulocyte‐colony stimulating factor (rhG‐CSF) primed donors and to determine whether there is a statistical association between the dose infused megakaryocytic precursors and the time course of the platelet recovery following an allogeneic PBSC transplantation. Twenty‐six patients with various hematologic malignancies transplanted from their HLA identical siblings between July 1997 and December 1999 were used. All patients except one with severe aplastic anemia who had cyclophosphamide (CY) alone received busulfan‐CY as preparative regimen and cyclosporine‐methotrexate for GVHD prophylaxis. Normal healthy donors were given rhG‐CSF 10 μg/kg/day subcutaneously twice daily and PBSCs were collected on days 5 and 6. The median number of infused CD34+, CD41+ and CD42+ cells were 6.61 × 10⁶/kg (range 1.47–21.41), 54.85 × 10⁴/kg (5.38–204.19), and 49.86 × 10⁴/kg (6.82–430.10), respectively. Median days of ANC 0.5 × 10⁹/L and platelet 20 × 10⁹/L were 11.5 (range 9–15) and 13 (8–33), respectively. In this study, the number of CD41+ and CD42+ cells infused much better correlated than the number of CD34+ cells infused with the time to platelet recovery of 20 × 10⁹/L in 26 patients receiving an allogeneic match sibling PBSC transplantation (r = ?0.727 and P < 0.001 for CD41+ cells, r = ?0.806 and P < 0.001 for CD42+ cells, r = ?0.336 and P > 0.05 for CD34+ cells). There was an inverse correlation between the number of infused CD41+ and CD42+ cells and duration of platelet engraftment. Therefore, as the number of CD41+ and CD42+ cells increased, duration of platelet engraftment (time to reach platelet count of ≥ 20 × 10⁹/L) shortened significantly. Based on this data we may conclude that flow cytometric measurement of CD41+ and CD42+ progenitor cells may provide an accurate indication of platelet reconstitutive capacity of the allogeneic PBSC transplant. J. Clin. Apheresis. 16:67–73, 2001. © 2001 Wiley‐Liss, Inc.     

Storage characteristics of cord blood progenitor cells: report of a multicenter study by the cellular therapies team of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative

BACKGROUND: Most hematopoietic progenitor cell (HPC) products are infused or processed shortly after collection, but in some cases this may be delayed for up to 48 hours. A number of variables such as temperature and cell concentration are of critical importance for the integrity of HPCs during this time. STUDY DESIGN AND METHODS: We evaluated critical variables using cord blood HPC units that were divided equally and stored at 4°C versus room temperature (RT) for up to 96 hours. Total nucleated cell (TNC) and mononuclear cell (MNC) counts, viable CD34+ cell counts, and CD45+ cell viability as well as colony‐forming unit–granulocyte‐macrophage (CFU‐GM) present over time at each temperature were determined. RESULTS: Overall, the data indicate that with the exception of viable CD34+ cells, there was a significant decrease in each variable measured for 72 to 96 hours and, with the exception of viable CD34+ cells and CFU‐GM, the reductions were significantly greater in RT units than 4°C units. There was an increase in viable CD34+ count for units where TNC count was greater than 8.5 × 10⁹/L, compared with units where TNC count was less than 8.5 × 10⁹/L, that was different for each storage temperature. CONCLUSIONS: Cord blood HPC collections maintained at 4°C retained higher TNC counts, MNC counts, and CD45+ cell viability over a 72‐ to 96‐hour storage period.     

Successful collection and engraftment of autologous peripheral blood progenitor cells in poorly mobilized patients receiving high-dose granulocyte colony-stimulating factor

Background : Granulocyte Colony‐Stimulating Factor (G‐CSF) alone or in conjunction with chemotherapy is commonly used to mobilize hematopoietic progenitor cells (HPC) into peripheral blood for progenitor cell harvest for autologous HPC transplantation. However, in up to 30% of patients, HPC are not effectively mobilized. In this study, we report the efficacy and safety profiles of a mobilization strategy using high‐dose (up to 36 μg/kg) G‐CSF in poorly mobilized patients. Study Design and Methods : Retrospective medical record reviews were performed for 392 patients who underwent autologous peripheral blood progenitor cell collection. A total of 56 patients were given high‐dose G‐CSF due to very ineffective mobilization and 35 of these patients underwent autologous HPC transplantation. The efficacy of mobilization, apheresis collection, and infusion were reviewed and analyzed. Results : More than 2.5 × 10⁶ CD34/Kg were collected in 88% of patients (49 of 56) who were placed on high‐dose G‐CSF due to very ineffective mobilization. Of the 35 patients who underwent HPC transplantation using the progenitor cells that were mobilized with high‐dose G‐CSF due to very ineffective mobilization, all had rapid and complete neutrophil and platelet engraftment comparable with good mobilizers. Conclusion : We conclude that collection of HPC using hyperstimulation with G‐CSF is an effective alternative approach for HPC harvest for poorly mobilized patients. J. Clin. Apheresis 27:235–241, 2012. © 2012 Wiley Periodicals, Inc.     

Effects of extended transport on cryopreserved allogeneic hematopoietic progenitor cell (HPC) product quality and optimal methods to assess HPC stability

Background

Since the beginning of the COVID-19 pandemic, cryopreservation of hematopoietic progenitor cell (HPC) products has been increasingly used to ensure allogeneic donor graft availability prior to recipient conditioning for transplantation. However, in addition to variables such as graft transport duration and storage conditions, the cryopreservation process itself may adversely affect graft quality. Furthermore, the optimal methods to assess graft quality have not yet been determined.

Study Design and Methods

A retrospective review was performed on all cryopreserved HPCs processed and thawed at our facility from 2007 to 2020, including both those collected onsite and by the National Marrow Donor Program (NMDP). HPC viability studies were also performed on fresh products, retention vials, and corresponding final thawed products by staining for 7-AAD (flow cytometry), AO/PI (Cellometer), and trypan blue (manual microscopy). Comparisons were made using the Mann–Whitney test.

Results

For HPC products collected by apheresis (HPC(A)), pre-cryopreservation and post-thaw viabilities, as well as total nucleated cell recoveries were lower for products collected by the NMDP compared to those collected onsite. However, there were no differences seen in CD34+ cell recoveries. Greater variation in viability testing was observed using image-based assays compared to flow-based assays, and on cryo-thawed versus fresh samples. No significant differences were observed between viability measurements obtained on retention vials versus corresponding final thawed product bags.

Discussion

Our studies suggest extended transport may contribute to lower post-thaw viabilities, but without affecting CD34+ cell recoveries. To assess HPC viability prior to thaw, testing of retention vials offers predictive utility, particularly when automated analyzers are used.     

Sequential transplants using mobilized peripheral blood progenitor cells

Modest success has been achieved with the use of high-dose cytotoxic therapy and bone marrow transplantation in solid tumors. Patient outcome can potentially be improved with further intensification of the therapy. The rapid hematologic recovery achieved with mobilized peripheral blood progenitor cells (PBPC) may reduce the toxicity of transplantation enabling the use of sequential courses of myeloablative therapy. We report on 42 patients with solid tumors enrolled in a tandem transplant protocol involving the use of PBPC mobilized with cyclophosphamide (4 g/m²), etoposide (1 g/m²), and granulocyte-colony-stimulating factor (G-CSF: 10 μg/kg/day). This regimen significantly increased the number of circulating progenitor cells; only 1-2 aphereses were sufficient to collect 2.5 × 10⁸/kg mononuclear cells, our goal for each transplant course. The median number of circulating colony-forming units (CFU) and CD34+ cells obtained for each transplant course were 70.3 × 10⁴/kg and 11.7 × 10⁶/kg, respectively. There was a significant correlation between the numbers of CD34+ cells and CFU measured in the apheresis product (r = 0.49, P = .003). The first transplant regimen given to 38 patients consisted of thiotepa, carboplatin, and cyclophosphamide. The second transplant regimen given to 29 patients consisted of busulfan and etoposide. Hematologic recovery was comparable after each of the two transplant courses. The median time to neutrophil recovery over 0.5 × 10⁹/L and to platelet transfusion independence was 9 and 8 days, respectively. There was no difference in engraftment rates after transplant with PBPC only (n = 28 courses) compared to transplant with PBPC plus bone marrow (n = 39 courses). There was a significant correlation between hematologic recovery after transplant and the number of CD34+ cells present in the PBPC. In conclusion, 1) PBPC are significantly mobilized with this combination chemotherapy and G-CSF, 2) mobilized PBPC result in rapid engraftment after myeloablative therapy, 3) hematologic recovery rates are comparable after sequential PBPC transplants, 4) PBPC alone are sufficient for long-term engraftment, and 5) rapid engraftment after PBPC transplant enables the use of a second course of myeloablative therapy within a short interval of time.     

Cord blood banking and transplantation at the Mexican Institute of Social Security: the first 5 years

BACKGROUND: In January 2005, the Cord Blood Bank (CBB) at the Mexican Institute of Social Security initiated activities. Herein, we describe the experience generated during this period (January 1, 2005‐December 31, 2009). STUDY DESIGN AND METHODS: Good manufacturing practices and standard operating procedures were used to address donor selection, as well as umbilical cord blood (UCB) collection, processing, and cryopreservation. Based mainly on HLA and nucleated cell content, specific UCB units were thawed, processed, and released for transplantation. RESULTS: A total of 589 UCB units were stored, representing 54% of the total number of units collected. Forty‐eight units (8.14% of the stored units) were released for transplantation of 36 patients. Twenty‐six patients (72% of cases) corresponded to patients with acute leukemia, five (14%) to patients with marrow failure, and the rest (five; 14%) to patients with hemoglobinopathies and other syndromes. The median number of nucleated cells infused per patient was 6.71 × 10⁷/kg and the median number of CD34+ cells was 4.8 × 10⁵/kg. Current engraftment data indicate that engraftment occurred in 56%, and no engraftment in 44%, of cases. Engraftment was more frequent (59%) in patients that received more than 3 × 10⁷ total nucleated cells (TNCs)/kg body weight, than in those receiving fewer than 3 × 10⁷ TNCs/kg (40%). Myeloid engraftment was observed 7 to 54 days posttransplant (median, 23 days), whereas platelet engraftment was detected on Days 12 to 87 posttransplant (median, 38 days). To date, the disease‐free survival rate was 41% and the overall survival was 47%, with survival periods of 126 to 1654 days. CONCLUSION: Although the experience presented herein is still limited and the period of analysis is still short, the results obtained during these 5 years are encouraging.