Autologous peripheral blood progenitor cells cryopreserved with 5 and 10 percent dimethyl sulfoxide alone give comparable hematopoietic reconstitution after transplantation

Impact of lower concentrations of dimethyl sulfoxide on cryopreservation of autologous hematopoietic stem cells: a systematic review and meta-analysis of controlled clinical studies

BACKGROUND AIMS

Cryopreservation of hematopoietic stem cells (HSCs) is crucial for autologous transplantation, cord blood banking and other special circumstances. Dimethyl sulfoxide (DMSO) is used most commonly for cryopreserving HSC products but can cause infusional toxicities and affect cell viability and engraftment after transplant. A systematic review of controlled studies using lower concentrations of DMSO to cryopreserve HSC products in clinical transplant studies is needed to determine the effect of reducing DMSO concentrations on post-thaw cell viability, initial engraftment and adverse effects on patient health.

METHODS

All studies identified in our systematic search (to July 11, 2023) examining the use of cryopreserved peripheral blood stem cells (PBSCs) for autologous stem cell transplantation (AHCT) were included. Meta-analysis was performed to determine how varying the concentration of DMSO during cryopreservation effects post-thaw cell viability, initial engraftment and adverse effects on patient health.

RESULTS

A total of 1547 studies were identified in our systematic search, with seven published articles meeting eligibility for inclusion in meta-analysis. All patients underwent AHCT using (PBSCs) to treat hematologic malignancies. The viability of CD34+ cells post thaw was greater when cryopreserved with 5% DMSO compared with 10% DMSO, with lower rates of adverse side effects in patients. DMSO concentration had minimal impact on rates of initial engraftment. Significant heterogeneity in outcome reporting was observed and the potential for bias was identified in all studies.

CONCLUSIONS

Reducing the concentration of DMSO from 10% to 5% during cryopreservation of autologous PBSCs may improve cell viability and reduce DMSO-associated adverse effects in patients undergoing AHCT. Data from more studies with similar patients and standard outcome reporting are needed to increase confidence in our initial observations.

PROTOCOL REGISTRATION

PROSPERO; registration number CRD42023476809 registered November 8, 2023.

Loss of CD34+ Cells and Effect of the Number of Viable Cryopreserved CD34+ Cells in the Infused Blood Grafts on Hematologic Recovery, Progression-Free Survival and Overall Survival in NHL Patients After Autologous Stem Cell Transplantation

PATIENTS

This post-hoc study aimed to find out factors affecting graft viable CD34+ cell loss during processing and cryopreservation in 129 non-Hodgkin lymphoma (NHL) patients receiving autologous stem cell transplantation (auto-SCT) and the impact of a low (< 2.0 × 106/kg, group A) and a decent number (≥ 2 × 106/kg, group B) of viable CD34+ cells infused on the hematologic recovery, progression-free survival (PFS) and overall survival (OS) after auto-SCT.

RESULTS

The median loss of viable CD34+ cells during cryopreservation was higher in group A (47% vs. 19%, p < .001). A higher yield of CD34+ cells at the first apheresis in group B (p = .002) was linked with greater loss of viable graft CD34+ cells after cryopreservation. Filgrastim (FIL) use for mobilization seemed to associate with higher viable CD34+ cell loss compared to pegfilgrastim (PEG) or lipegfilgrastim (LIPEG) in both groups (in group A FIL 66 vs. PEG 35%, p = .006; in group B FIL 37 vs. PEG 15 vs. LIPEG 13%, p < .001). Hematologic recovery after auto-SCT was faster in group B. Neither viable CD34+ cell loss during storage nor viable CD34+ cell number < 2.0 × 106/kg infused affected on PFS or OS.

CONCLUSIONS

G-CSF type used in mobilization and mobilization capacity were found to correlate with viable CD34+ cell loss during processing and storage. Most importantly, low infused viable CD34+ cell count did not seem to impact on PFS or OS.

Impact of the number of cryopreserved CD34+ cells in the infused blood grafts on hematologic recovery and survival in myeloma patients after autologous stem cell transplantation: Experience from the GOA study

BACKGROUND

Prospective data on the impact of CD34⁺ cell loss during cryopreservation and the amount of cryopreserved CD34⁺ cells infused after high-dose therapy on hematologic recovery and post-transplant outcome in multiple myeloma (MM) are scarce.

PATIENTS AND METHODS

This post-hoc study aimed to investigate factors associating with CD34⁺ cell loss during cryopreservation and the effects of the infusion of a very low number (<1.0 × 10⁶ /kg, group A), low number (1-1.9 × 10⁶ /kg, group B), and optimal number (≥2 × 10⁶ /kg, group C) of thawed viable CD34⁺ cells on hematologic recovery, progression free survival, and overall survival after autologous stem cell transplantation among 127 patients with MM.

RESULTS

In group C, pegfilgrastim use (P = 0.001), plerixafor use (P = 0.039), and older age ≥ 60 years (P = 0.026) were associated with less loss of CD34⁺ cells during cryopreservation. Better mobilization efficacy correlated with greater CD34⁺ cell loss in group B (P = 0.013 and P = 0.001) and in group C (P < 0.001 and P < 0.001). Early platelet engraftment was slowest in group A (20 d vs 12 d in group B vs 11 d in group C, P = 0.003). The infused viable CD34⁺ cell count <1.0 × 10⁶ /kg seemed not to have influence on PFS (P = 0.322) or OS (P = 0.378) in MM patients.

CONCLUSIONS

Cryopreservation impacts significantly on the CD34⁺ cell loss. A very low number of graft viable CD34⁺ cells did not affect PFS or OS.

Effects of storage media, supplements and cryopreservation methods on quality of stem cells

Despite a vast amount of different methods, protocols and cryoprotective agents (CPA), stem cells are often frozen using standard protocols that have been optimized for use with cell lines, rather than with stem cells. Relatively few comparative studies have been performed to assess the effects of cryopreservation methods on these stem cells. Dimethyl sulfoxide (DMSO) has been a key agent for the development of cryobiology and has been used universally for cryopreservation. However, the use of DMSO has been associated with in vitro and in vivo toxicity and has been shown to affect many cellular processes due to changes in DNA methylation and dysregulation of gene expression. Despite studies showing that DMSO may affect cell characteristics, DMSO remains the CPA of choice, both in a research setting and in the clinics. However, numerous alternatives to DMSO have been shown to hold promise for use as a CPA and include albumin, trehalose, sucrose, ethylene glycol, polyethylene glycol and many more. Here, we will discuss the use, advantages and disadvantages of these CPAs for cryopreservation of different types of stem cells, including hematopoietic stem cells, mesenchymal stromal/stem cells and induced pluripotent stem cells.

Reduced dimethyl sulfoxide concentrations successfully cryopreserve human hematopoietic stem cells with multi-lineage long-term engraftment ability in mice

BACKGROUND AIMS

The cryopreservation of hematopoietic stem cells (HSCs) in dimethyl sulfoxide (DMSO) is used widely, but DMSO toxicity in transplant patients and the effects of DMSO on the normal function of cryopreserved cells are concerns. To address these issues, in vitro and clinical studies have explored using reduced concentrations of DMSO for cryopreservation. However, the effect of reducing DMSO concentration on the efficient cryopreservation of HSCs has not been directly measured.

METHODS

Cryopreservation of human bone marrow using 10%, 7.5% and 5% DMSO concentrations was examined. Cell counting, flow cytometry and colony assays were used to analyze different cell populations. The recovery of stem cells was enumerated using extreme limiting dilution analysis of long-term multi-lineage engraftment in immunodeficient mice. Four different methods of analyzing human engraftment were compared to ascertain stem cell engraftment: (i) engraftment of CD33⁺ myeloid, CD19⁺ B-lymphoid, CD235a⁺ erythroid and CD34⁺ progenitors; (ii) engraftment of the same four populations plus CD41⁺CD42b⁺ platelets; (iii) engraftment of CD34⁺⁺CD133⁺ cells; and (iv) engraftment of CD34⁺⁺CD38^- cells.

RESULTS

Hematopoietic colony-forming, CD34^++/+, CD34⁺⁺CD133⁺ and CD34⁺⁺CD38^- cells were as well preserved with 5% DMSO as they were with the higher concentrations tested. The estimates of stem cell frequencies made in the xenogeneic transplant model did not show any significant detrimental effect of using lower concentrations of DMSO. Comparison of the different methods of gauging stem cell engraftment in mice led to different estimates of stem cell numbers, but overall, all measures found that reduced concentrations of DMSO supported the cryopreservation of HSCs.

CONCLUSION

Cryopreservation of HSCs in DMSO concentrations as low as 5% is effective.

Intracellular delivery of trehalose renders mesenchymal stromal cells viable and immunomodulatory competent after cryopreservation

Trehalose is a nontoxic disaccharide and a promising cryoprotection agent for medically applicable cells. In this study, the efficiency of combining trehalose with reversible electroporation for cryopreservation of two types of human mesenchymal stromal cells was investigated: adipose-derived stromal cells, and umbilical-cord-derived stromal cells. Comparable results to standard dimethyl sulfoxide cryopreservation protocols were achieved, even without extensive electroporation parameters and protocol optimization. The presence of high extracellular trehalose resulted in comparable cell viabilities without and with electroporation. According to the determination of trehalose concentrations, 250 mM extracellular trehalose resulting in, 20 mM to 50 mM intracellular trehalose were sufficient for successful cryopreservation of cells. With electroporation, higher (i.e. 50 mM to 90 mM) intracellular trehalose was achieved after cryopreservation, although cell survival was not improved significantly. To evaluate the impact of electroporation and cryopreservation on cells, stress and immune-activation-related gene expression were analyzed. Electroporation and/or cryopreservation resulted in increased SOD2 and HSPA1A expression. Despite the increased stress response, the high up-regulation by mesenchymal stromal cells of immunomodulatory genes in the inflammatory environment was not affected. Highest expression was seen for the IDO1 and TSG6 genes. In conclusion, cryopreservation of mesenchymal stromal cells in trehalose results in comparable characteristics to their cryopreservation using dimethyl sulfoxide.

Current and Future Perspectives for the Cryopreservation of Cord Blood Stem Cells

Hematopoietic stem cell (HSC) transplantation is a well-established procedure for the treatment of many blood related malignancies and disorders. Before transplantation, HSC are collected and cryopreserved until use. The method of cryopreservation should preserve both the number and function of HSC and downstream progenitors responsible for long- and short-term engraftment, respectively. This is especially critical for cord blood grafts, since the cell number associated with this stem cell source is often limiting. Loss of function in cryopreserved cells occurs following cryoinjuries due to osmotic shock, dehydration, solution effects and mechanical damage from ice recrystallization during freezing and thawing. However, cryoinjuries can be reduced by 2 mitigation strategies; the use of cryoprotectants (CPAs) and use of control rate cooling. Currently, slow cooling is the most common method used for the cryopreservation of HSC graft. Moreover, dimethyl-sulfoxide (DMSO) and dextran are popular intracellular and extracellular CPAs used for HSC grafts, respectively. Yet, DMSO is toxic to cells and can cause significant side effects in stem cells' recipients. However, new CPAs and strategies are emerging that may soon replace DMSO. The aim of this review is to summarise key concepts in cryobiology and recent advances in the field of HSC cryobiology. Other important issues that need to be considered are also discussed such as transient warming events and thawing of HSC grafts.

Label-free on chip quality assessment of cellular blood products using real-time deformability cytometry

Without cellular blood products such as platelet concentrates (PC), red blood cell concentrates (RCC), and hematopoietic stem cells (HPSC) modern treatments in medicine would not be possible. An unresolved challenge is the assessment of their quality with minimal cell manipulation. Minor changes in production, storage conditions, or blood bag composition may impact cell function, which can have important consequences on product integrity. This is especially relevant for personalized medicine, such as autologous T-cell therapy. Today a robust methodology that globally determines cell status directly before transfusion or transplantation is lacking. We demonstrate that measuring viscoelastic characteristics of peripheral blood cells using real-time deformability cytometry (RT-DC) provides comprehensive information on product quality, which is not accessible using conventional quality control tests. In addition, RT-DC requires few cells, a minimal sample volume and has a rapid turnaround time. We compared RT-DC to standard in vitro quality assays assessing: i) PC after storage at 4 °C and room temperature; ii) magnetic nanoparticle labeled platelets; iii) RCC stored in blood bags with different plasticizers; iv) RCC after gamma irradiation; and v) HPSC after cryopreservation with 5% or 10% dimethyl sulfoxide, respectively. Additionally, we evaluated the engraftment time of patients' platelets and leukocytes after transplantation of HPSC products. Our results demonstrate that label-free mechano-phenotyping can be used as a potential biomarker for quality assessment of cell-based pharmaceutical products.

Dimethyl sulfoxide-free cryopreservation for cell therapy: A review

Cell-based therapeutics promise to transform the treatment of a wide range of diseases including cancer, genetic and degenerative disorders, or severe injuries. Many of the commercial and clinical development of cell therapy products require cryopreservation and storage of cellular starting materials, intermediates and/or final products at cryogenic temperature. Dimethyl sulfoxide (Me₂SO) has been the cryoprotectant of choice in most biobanking situations due to its exceptional performance in mitigating freezing-related damages. However, there is concern over the toxicity of Me₂SO and its potential side effects after administration to patients. Therefore, there has been growing demand for robust Me₂SO-free cryopreservation methods that can improve product safety and maintain potency and efficacy. This article provides an overview of the recent advances in Me₂SO-free cryopreservation of cells having therapeutic potentials and discusses a number of key challenges and opportunities to motivate the continued innovation of cryopreservation for cell therapy.

The value of the post-thaw CD34+ count with and without DMSO removal in the setting of autologous stem cell transplantation

BACKGROUND

CD34+ cell count correlates with engraftment potency after autologous stem cell transplantation. Assessment of CD34+ mainly occurs after apheresis and before cryopreservation with dimethyl sulfoxide (DMSO). The influence of postthaw CD34+ cell numbers over time to engraftment is not well studied, and determination of postthaw CD34+ cell counts is challenging for a variety of reasons. The aim of this retrospective study was to systematically assess the value of postthaw CD34+ cell counts in autologous grafts with and without DMSO removal.

STUDY DESIGN AND METHODS

Between January 2008 and December 2015, 236 adult patients underwent a total of 292 autologous stem cell transplantations. Median age at transplantation was 56 years, and the main indication was multiple myeloma (60%). DMSO removal was done in 96 grafts (33%), either by centrifugation or by Sepax method.

RESULTS

Patients receiving grafts containing DMSO showed a significantly faster platelet (p = 0.02) and RBC (p = 0.001) engraftment. DMSO removal was not associated with fewer infusion-related adverse events. We observed a good correlation between CD34+ cell count after apheresis and CD34+ cell count after thawing/washing (r = 0.931). Ninety grafts (31%) showed a significant loss of viable CD34+ cells, which translated into a delayed engraftment.

CONCLUSION

DMSO removal was associated with delayed platelet and RBC engraftment without preventing adverse events. CD34+ cell enumeration after thawing remains difficult to perform, but grafts showing higher cell loss during cryopreservation and thawing are associated with slower engraftment. Prospective studies on the role of DMSO removal and postthaw CD34+ enumeration using defined protocols are needed.

Adverse reactions of dimethyl sulfoxide in humans: a systematic review

Background: Dimethyl sulfoxide (DMSO) has been used for medical treatment and as a pharmacological agent in humans since the 1960s. Today, DMSO is used mostly for cryopreservation of stem cells, treatment of interstitial cystitis, and as a penetrating vehicle for various drugs. Many adverse reactions have been described in relation to the use of DMSO, but to our knowledge, no overview of the existing literature has been made. Our aim was to conduct a systematic review describing the adverse reactions observed in humans in relation to the use of DMSO. Methods: This systematic review was reported according to the PRISMA-harms (Preferred Reporting Items for Systematic reviews and Meta-Analysis) guidelines. The primary outcome was any adverse reactions occurring in humans in relation to the use of DMSO. We included all original studies that reported adverse events due to the administration of DMSO, and that had a population of five or more. Results: We included a total of 109 studies. Gastrointestinal and skin reactions were the commonest reported adverse reactions to DMSO. Most reactions were transient without need for intervention. A relationship between the dose of DMSO given and the occurrence of adverse reactions was seen. Conclusions: DMSO may cause a variety of adverse reactions that are mostly transient and mild. The dose of DMSO plays an important role in the occurrence of adverse reactions. DMSO seems to be safe to use in small doses. Registration: PROSPERO CRD42018096117.

Adverse reactions of dimethyl sulfoxide in humans: a systematic review

Background: Dimethyl sulfoxide (DMSO) has been used for medical treatment and as a pharmacological agent in humans since the 1960s. Today, DMSO is used mostly for cryopreservation of stem cells, treatment of interstitial cystitis, and as a penetrating vehicle for various drugs. Many adverse reactions have been described in relation to the use of DMSO, but to our knowledge, no overview of the existing literature has been made. Our aim was to conduct a systematic review describing the adverse reactions observed in humans in relation to the use of DMSO.

Methods: This systematic review was reported according to the PRISMA-harms (Preferred Reporting Items for Systematic reviews and Meta-Analysis) guidelines. The primary outcome was any adverse reactions occurring in humans in relation to the use of DMSO. We included all original studies that reported adverse events due to the administration of DMSO, and that had a population of five or more.

Results: We included a total of 109 studies. Gastrointestinal and skin reactions were the commonest reported adverse reactions to DMSO. Most reactions were transient without need for intervention. A relationship between the dose of DMSO given and the occurrence of adverse reactions was seen.

Conclusions: DMSO may cause a variety of adverse reactions that are mostly transient and mild. The dose of DMSO plays an important role in the occurrence of adverse reactions. DMSO seems to be safe to use in small doses.

Registration: PROSPERO CRD42018096117.

Autologous Graft-versus-Tumor Effect: Reality or Fiction?

In contrast to allogeneic hematopoietic stem cell transplantation, the current dogma is not an evidence of graft-versus-tumor effect in autologous hematopoietic stem cell transplantation; thus, it is assumed that autologous hematopoietic stem cell transplantation only relies on the high-dose chemotherapy to improve clinical outcomes. However, recent studies argue in favor of the existence of an autologous graft-versus-tumor without the detrimental complications of graft-versus-host disease due to the nonspecific immune response from the infused donor alloreactive immune effector cells in allogeneic hematopoietic stem cell transplantation. Herein, this paper reviews the clinical evidence of an autologous graft-versus-tumor effect based on the autograft collected and infused host immune effector cells and host immunity recovery after autologous hematopoietic stem cell transplantation affecting clinical outcomes in cancer patients.

Severe motor aphasia after reinfusion of cryopreserved autologous stem cells after myeloablative conditioning

BACKGROUND

Autologous peripheral blood stem cells (PBSCs) are usually cryopreserved before high-dose chemotherapy (HDCT) and autologous peripheral blood stem cell transplantation (PBSCT). The freezing process requires the addition of cryoprotectants such as dimethyl sulfoxide (DMSO), which is vital for cell viability in frozen aliquots. DMSO has a number of well-described side effects. However, severe neurologic side effects assigned to DMSO are exceedingly rare.

CASE REPORT

A 64-year-old female underwent HDCT followed by PBSCT as consolidation therapy in relapsed high-grade (Grade 3B) Stage IIIA follicular lymphoma. PBSCs were mobilized using granulocyte-colony stimulating factor and plerixafor after the second cycle of R-DHAP (rituximab, dexamethasone, high-dose Ara-C, cisplatin) salvage chemotherapy. A total of 7.18 × 10⁶ /kg body weight CD34+ cells were cryopreserved using 10% DMSO. HDCT was administered some weeks later followed by reinfusion of two bags of PBSCs, each containing 98 mL with 1.6 × 10⁶ /kg body weight CD34+ cells. Within a few minutes the patient developed a motor aphasia and became very agitated. Brain imaging did not reveal any pathologic finding. After being transferred to the intensive care unit the patient's condition steadily improved and the motor aphasia resolved completely within 6 hours after its onset.

CONCLUSION

This is, to our knowledge, the first report to describe an episode of severe motor aphasia during PBSCT. Given the close timely correlation with PBSCT, this episode appears to be caused by dimethyl sulfoxide (DMSO) and might possibly have been prevented by use of lower concentrations of DMSO.

Cryopreservation in Closed Bag Systems as an Alternative to Clean Rooms for Preparations of Peripheral Blood Stem Cells

Autologous and allogeneic stem cell transplantation (SCT) represents a therapeutic option widely used for hematopoietic malignancies. One important milestone in the development of this treatment strategy was the development of effective cryopreservation technologies resulting in a high quality with respect to cell viability as well as lack of contamination of the graft.Stem cell preparations have been initially performed within standard laboratories as it is routinely still the case in many countries. With the emergence of cleanrooms, manufacturing of stem cell preparations within these facilities has become a new standard mandatory in Europe. However, due to high costs and laborious procedures, novel developments recently emerged using closed bag systems as reliable alternatives to conventional cleanrooms. Several hurdles needed to be overcome including the addition of the cryoprotectant dimethylsulfoxide (DMSO) as a relevant manipulation. As a result of the development, closed bag systems proved to be comparable in terms of product quality and patient outcome to cleanroom products. They also comply with the strict regulations of good manufacturing practice.With closed systems being available, costs and efforts of a cleanroom facility may be substantially reduced in the future. The process can be easily extended for other cell preparations requiring minor modifications as donor lymphocyte preparations. Moreover, novel developments may provide solutions for the production of advanced-therapy medicinal products in closed systems.

Analysis of the recovery of cryopreserved and thawed CD34+ and CD3+ cells collected for hematopoietic transplantation

BACKGROUND

Cryopreservation is often used to store cellular therapies, but little is known about how well CD3+ or CD34+ cells tolerate this process.

STUDY DESIGN AND METHODS

Viable CD34+ cell recoveries were analyzed from related and unrelated donor granulocyte-colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cell (PBSC) products and viable CD3+ cell recoveries from G-CSF-mobilized and nonmobilized apheresis products from related and unrelated donors. All products were cryopreserved with 5% dimethyl sulfoxide and 6% pentastarch using a controlled-rate freezer and were stored in liquid nitrogen. Related donor products were cryopreserved immediately after collection and unrelated donor products greater than 12 hours postcollection.

RESULTS

The postthaw recovery of CD34+ cells from related donor PBSCs was high (n = 86; 97.5 ± 23.1%) and there was no difference in postthaw CD34+ cell recovery from unrelated donor PBSCs (n = 14; 98.8 ± 37.2%; p = 0.863). In related donor lymphocyte products the postthaw CD3+ cell recovery (n = 48; 90.7 ± 21.4%) was greater than that of unrelated donor products (n = 14; 66.6 ± 35.8%; p = 0.00251). All unrelated donor lymphocyte products were from G-CSF-mobilized products, while most related donor lymphocyte products were from nonmobilized products. A comparison of the CD3+ cell recovery from related donor G-CSF-mobilized products (n = 19; 85.0 ± 29.2%) with that of unrelated donor products found no significant difference (p = 0.137).

CONCLUSIONS

The postthaw recovery of CD34+ cells was high in both related and unrelated donor products, but the recovery of CD3+ cells in unrelated donor G-CSF-mobilized products was lower. G-CSF-mobilized unrelated donor products may contain fewer CD3+ cells than non-G-CSF-exposed products upon thaw and, when indicated, cell doses should be monitored.

Manufacturing and banking of mesenchymal stem cells

INTRODUCTION

Mesenchymal stem cells (MSC) and MSC-like cells hold great promise and offer many advantages for developing effective cellular therapeutics. Current trends indicate that the clinical application of MSC will continue to increase markedly. For clinical applications, large numbers of MSC are usually required, ideally in an off-the-shelf format, thus requiring extensive MSC expansion ex vivo and subsequent cryopreservation and banking.

AREAS COVERED

To exploit the full potential of MSC for cell-based therapies requires overcoming significant cell-manufacturing, banking and regulatory challenges. The current review will focus on the identification of optimal cell source for MSC, the techniques for production scale-up, cryopreservation and banking and the regulatory challenges involved.

EXPERT OPINION

There has been considerable success manufacturing and cryopreserving MSC at laboratory scale. Surprisingly little attention, however, has been given to translate these technologies to an industrial scale. The development of cost-effective advanced technologies for producing and cryopreserving commercial-scale MSC is important for successful clinical cell therapy.

Hematologic, immunologic reconstitution, and outcome of 342 autologous peripheral blood stem cell transplantations after cryopreservation in a -80°C mechanical freezer and preserved less than 6 months

BACKGROUND

Controlled-rate freezing and storage in nitrogen is the standard technique for cryopreservation of peripheral hematopoietic progenitor cells (PHPCs) but presents high cost and dimethyl sulfoxide (DMSO) toxicity. Cryopreservation at -80°C, by uncontrolled rate freezing with only 3.5% DMSO, preserves the functional capacities of PHPCs, produces successful engraftment, and reduces toxicity during infusion.

STUDY DESIGN AND METHODS

Long-term hematopoietic and immunologic reconstitution for 342 autografts (311 adults, 31 children) after PHPCs were cryopreserved at -80°C was studied at 3, 6, and 12 months. The median (range) storage time of PHPCs cryopreserved was 1.7 (0.1-5.99) months.

RESULTS

Hemoglobin (Hb), white blood cells, and platelets (PLTs) reach normal values to trilineage at 12 months for 39% patients. Multivariate analysis shows a significant impact on CD34+ infused and on conditioning regimen for PLTs. Hb was influenced by growth factor administration at 3 months. Long-term recovery is also highly dependent on blood counts (Hb, PLT, and neutrophil) at start of high-dose chemotherapy. Only 43% of patients had reached normal lymphocyte values at 12 months after transplant, and a profound CD4+ T-lymphocyte deficit remained, as others reported.

CONCLUSION

Transplantation with PHPCs cryopreserved at -80°C for no more than 6 months is satisfactory for long-term hematopoietic and immunologic reconstitution, even if a profound CD4+ T lymphocyte deficit persists at 1 year. This easier and cheaper cryopreservation method also leads to successful engraftment.

Increased apoptosis in cryopreserved autologous hematopoietic progenitor cells collected by apheresis and delayed neutrophil recovery after transplantation: a nested case-control study

BACKGROUND AIMS

Delayed neutrophil recovery following autologous hematopoietic stem cell transplantation (aHSCT) increases transplant-related morbidity. Apoptosis induced by cryopreservation and thawing of hematopoietic progenitor cells collected by apheresis (HPC-A) was investigated in this nested case-control study as a factor associated with delayed neutrophil recovery following aHSCT.

METHODS

Among patients with lymphoma who underwent aHSCT between 2000 and 2007 (n = 326), 13 cases of primary delayed neutrophil recovery and 22 age- and sex-matched controls were identified. Apoptosis and viability were measured using multiparameter flow cytometry, and colony-forming capacity was determined using semi-solid methylcellulose assays.

RESULTS

HPC-A grafts from cases and controls had similar percentages of viable mononuclear cells (MNC) and CD34+ progenitor cells, as determined by standard 7AAD dye exclusion methods measured before and after cryopreservation. Patients with delayed neutrophil recovery received increased numbers of apoptotic MNC (P = 0.02) but similar numbers of apoptotic CD34+ cells per kilogram measured after thawing. Apoptosis was more pronounced in MNC compared with CD34+ cells after thawing, and apoptosis was negligible in freshly collected HPC-A products. Patients with delayed neutrophil recovery had fewer total colony-forming unites (CFU) and CFU-granulocyte-macrophages (GM) per 10(5) viable post-thaw MNC compared with controls (P < 0.05).

CONCLUSIONS

Increased numbers of apoptotic MNC in thawed HPC-A products are associated with delayed neutrophil recovery after aHSCT. Studies that address factors contributing to increased apoptosis are needed, and measuring apoptosis in thawed HPC-A may have a role in the assessment of graft adequacy.

Effects of peripheral blood stem cell apheresis on systemic cytokine levels in patients with multiple myeloma

BACKGROUND AIMS. Pro-angiogenic cytokines can affect myeloma cell proliferation directly and indirectly through stimulation of cancer-associated angiogenesis. METHODS. We investigated how peripheral blood stem cell (PBSC) collection affected plasma angioregulatory cytokine levels in 15 consecutive myeloma patients. RESULTS. Plasma levels of hepatocyte growth factor (HGF) were significantly increased prior to apheresis in patients compared with donors, and a further increase was detected immediately after PBSC apheresis. HGF levels decreased within 24 h, but were still higher than the levels in healthy donors, whose HGF levels were not altered by platelet apheresis. Pre-apheresis levels of other angioregulatory cytokines, angiopoietin-2 and vascular endothelial growth factor (VEGF), were also increased in patients, whereas angiopoietin-1, angiogenin and basic fibroblast growth factor levels did not differ from healthy controls. PBSC harvesting decreased angiopoietin-1 and VEGF levels, increased the microvascular endothelial cell marker endocan levels but did not affect the other mediators. CONCLUSIONS. Our results show that PBSC apheresis alters systemic angioregulatory profiles in myeloma patients. This cytokine modulation is not a general characteristic of all apheresis procedures and was not seen in healthy platelet donors.

Stability of cryopreserved white blood cells (WBCs) prepared for donor WBC infusions

BACKGROUND

White blood cells (WBCs) collected from hematopoietic stem cell transplant donors are often given to the recipient to speed immune recovery or treat disease relapse. The postthaw recovery and viability of cryopreserved donor WBCs, stored for as long as 7 years, were assessed.

STUDY DESIGN AND METHODS

Total nucleated cell (TNC) cell recovery, CD3+ cell recovery, and TNC viability were measured in 311 clinical donor WBC products: 168 products were unmanipulated or minimally manipulated and 143 products were extensively manipulated. An additional 45 products were selected because they were stored for a longer duration; these were tested using both standard methods and global transcriptional analysis. All products were cryopreserved in 5% dimethyl sulfoxide (DMSO) plus 6% pentastarch and stored in liquid nitrogen.

RESULTS

The mean duration of storage of the 311 products was 143 days. Their TNC recovery was 92 ± 17%, CD3+ cell recovery was 76 ± 19%, and the TNC viability was 84 ± 6%. Duration of storage had no effect on TNC recovery, CD3+ cell recovery, or TNC viability of the 311 products. The mean duration of storage of the long-term stored products was 5.2 years; their TNC recovery (93 ± 14%) and the TNC viability (78 ± 13%) did not differ from the 311 products, but their CD3 cell recovery was greater (86 ± 22%; p = 0.0042). Gene expression profiles of the long-term-stored products revealed no differences due to storage duration.

CONCLUSIONS

Donor WBC products cryopreserved in 5% DMSO and 6% pentastarch can be stored in liquid nitrogen for at least 7 years.

Processing of hematopoietic stem cells from peripheral blood before cryopreservation: use of a closed automated system

BACKGROUND

Hematopoietic stem cell transplantation is commonly used to treat several oncohematologic diseases. The autologous hematopoietic progenitor cells collected through apheresis (HPC-A) must be cryopreserved and stored before use in vivo. Cell processing that precedes cryopreservation of HPC-A includes volume reduction aimed at reducing the amount of dimethyl sulfoxide used, as well as storage space.

STUDY DESIGN AND METHODS

The aim of our study was to assess the effectiveness of volume reduction performed with an automated closed system, namely, the Sepax S100 cell separation device (Biosafe SA). A total of 165 procedures were carried out on concentrates collected from 104 adult and pediatric patients. As a control group, 30 HPC-A units processed according to the standard method (i.e., centrifugation at a speed of 850 × g for 10 minutes, followed by manual plasma reduction) were evaluated.

RESULTS

The volume reduction obtained was 59% (range, 20.54%-84.21%; standard deviation [SD], ± 12.19%), going from 236 mL (range, 100-443 mL; SD, ± 80.41 mL) to 97 mL (range, 33.00-263.00 mL; SD, ± 47.41 mL); recovery of nucleated cells was 90% (range, 64.84%-105.93%; SD, ± 8.76%), while that of CD34+ cells was 91% (range, 59.30%-119.37%; SD, ± 13.30%). These values did not differ from those obtained using the standard method. Automated processing required 20 minutes versus 40 minutes of manual processing.

DISCUSSION

Our data demonstrate that volume reduction carried out with the Sepax S100 automated system was particularly effective; cell recovery was excellent and the time spent was short. Moreover, the closed system allows cell processing to be carried out in a contamination-controlled environment, in accordance with good manufacturing practice guidelines.

Hematopoietic engraftment of dimethyl sulfoxide-depleted autologous peripheral blood progenitor cells

BACKGROUND

Autologous stem cell transplantation with cryopreserved autografts is a prerequisite for high-dose chemotherapy in treatment of several malignancies. Adverse effects due to the cryoprotectant dimethyl sulfoxide (DMSO) vary from mild to severe. DMSO-associated adverse effects can be reduced by DMSO depletion before autograft infusion. The aim was to investigate whether DMSO depletion by manual single wash reduced frequency of adverse effects or had detrimental effects on the engraftment potential of peripheral blood progenitor cell (PBPC) autografts.

STUDY DESIGN AND METHODS

Ten percent DMSO was used to cryopreserve PBPC autografts for a total of 53 patients with multiple myeloma (n = 41), non-Hodgkin's lymphoma (n = 8), amyloidosis (n = 3), and polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes (POEMS) syndrome (n = 1). After high-dose chemotherapy, 34 patients received unmanipulated autografts, whereas for 19 patients the autografts were manually washed before stem cell infusion. Adverse effects after the infusion as well as neutrophil (neutrophil count >0.5 x 10(9)/L) and platelet (PLT) engraftment (PLT count >20 x 10(9)/L) for these two groups were compared.

RESULTS

DMSO depletion reduced the frequency of adverse effects significantly. Patients transplanted with DMSO-depleted autografts had similar neutrophil engraftment time as patients receiving unmanipulated autografts. PLT engraftment time, however, was significantly prolonged and PLT transfusion requirements significantly increased for patients receiving DMSO-depleted autografts, even though the numbers of infused CD34+ cells per kg did not differ between the groups.

CONCLUSIONS

DMSO depletion through a manual single wash is a time-consuming procedure that reduces adverse effects. Although the procedure leads to an increase of 2 days in PLT engraftment time, it can be recommended for selected patients with high risk of serious DMSO toxicity.