Long term cryopreservation in 5% DMSO maintains unchanged CD34+cells viability and allows satisfactory hematological engraftment after peripheral blood stem cell transplantation

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.

Sustained Hematopoietic Engraftment Potential after Prolonged Storage of Cryopreserved Hematopoietic Stem Cells (HSC) Used in Salvage Autologous Stem Cell Transplantation: Prolonged Storage of HSCs Sustains Hematological Reconstitution Potential

BACKGROUND

Salvage autologous hematopoietic stem cell transplantation (HSCT) is an effective treatment for patients with relapsed multiple myeloma (MM). Peripheral blood stem cells (PBSCs), a source of hematopoietic stem cells (HSCs), are collected prior to first transplant and adequate quantities of PBSCs can be collected and stored potentially for years to support at least two transplants for eligible patients. To ensure the safety of salvage HSCT used in the treatment of patients in subsequent relapse, PBSCs must retain the potential to engraft even after several years of cryopreservation. Although PBSC viability has been extensively studied using in vitro techniques, few publications describe the most rigorous functional potency measure: of patients receiving a myeloablative conditioning regimen. This study describes a large single-institution experience evaluating the engraftment kinetics of PBSCs used in salvage transplantation after multiple years of storage in comparison to first transplantation of the same patients in the treatment of MM.

STUDY DESIGN AND METHODS

A retrospective chart review of patients with MM undergoing HSCT from 2000 to 2021, identified 89 patients who received salvage autologous PBSC stored > 1 year after first HSCT. PBSC were cryopreserved and stored in vapor-phase liquid nitrogen refrigerators at a temperature of ≤ -150°C. All patients received a PBSC product for both transplants from the same collection cycle. Differences in CD34⁺ cell doses and days to engraftment between the first and salvage transplant were tested using a paired 2-tailed t-test and Wilcoxon signed-rank test. Univariate and multivariable linear regressions were used to determine association between storage time and days to engraftment, adjusting for CD34+ cell dose and conditioning regimen in the multivariable model.

RESULTS

The median storage time between day of initial collection and salvage transplant was 5.4 years (range, 1.0 - 19.7). Engraftment kinetics demonstrated a sustained neutrophil engraftment (absolute neutrophil count (ANC) > 0.5 × 10⁹ cells/L) at a median of 11 days after both the first and salvage transplant (ranges, 8 - 15 and 8 - 19 respectively, p<0.05). The median time to sustained platelet engraftment (> 20 × 10⁹ cells/L without transfusion support) was 13.5 days after first HSCT and 14 days after salvage HSCT (ranges, 9 - 27 and 10 - 56 respectively, p = 0.616). After adjusting for CD34+ cell doses and conditioning regimens, there was no association between the duration of cryopreservation and days to neutrophil (r = 0.178, p = 0.130) or platelet (r = 0.244, p = 0.100) engraftments.

CONCLUSION

Engraftment kinetics of the salvage HSCT are comparable to the first HSCT even when products are stored in vapor-phase nitrogen refrigerators for a median time of 5.4 years. There is no association between storage duration and time to engraftment when controlling for CD34+ dose and conditioning regimens. Prolonged storage of cryopreserved HSC products is a safe practice for MM patients undergoing salvage autologous HSCT.

Long-Term Cryopreservation Does Not Affect Quality of Peripheral Blood Stem Cell Grafts: A Comparative Study of Native, Short-Term and Long-Term Cryopreserved Haematopoietic Stem Cells

Cryopreserved haematopoietic progenitor cells are used to restore autologous haematopoiesis after high dose chemotherapy. Although the cells are routinely stored for a long period, concerns remain about the maximum storage time and the possible negative effect of storage on their potency. We evaluated the effect of cryopreservation on the quality of peripheral stem cell grafts stored for a short (3 months) and a long (10 years) period and we compared it to native products.The viability of CD34+ cells remained unaffected during storage, the apoptotic cells were represented up to 10% and did not differ between groups. The clonogenic activity measured by ATP production has decreased with the length of storage (ATP/cell 1.28 nM in native vs. 0.63 in long term stored products, P < 0.05). Only borderline changes without statistical significance were detected when examining mitochondrial and aldehyde dehydrogenase metabolic activity and intracellular pH, showing their good preservation during cell storage. Our experience demonstrates that cryostorage has no major negative effect on stem cell quality and potency, and therefore autologous stem cells can be stored safely for an extended period of at least 10 years. On the other hand, long term storage for 10 years and longer may lead to mild reduction of clonogenic capacity. When a sufficient dose of stem cells is infused, these changes will not have a clinical impact. However, in products stored beyond 10 years, especially when a low number of CD34+ cells is available, the quality of stem cell graft should be verified before infusion using the appropriate potency assays.

Differentiated Cells Derived from Hematopoietic Stem Cells and Their Applications in Translational Medicine

Hematopoietic stem cells (HSCs) and their development are one of the most widely studied model systems in mammals. In adults, HSCs are predominantly found in the bone marrow, from where they maintain homeostasis. Besides bone marrow and mobilized peripheral blood, cord blood is also being used as an alternate allogenic source of transplantable HSCs. HSCs from both autologous and allogenic sources are being applied for the treatment of various conditions like blood cancers, anemia, etc. HSCs can further differentiate to mature blood cells. Differentiation process of HSCs is being extensively studied so as to obtain a large number of pure populations of various differentiated cells in vitro so that they can be taken up for clinical trials. The ability to generate sufficient quantity of clinical-grade specialized blood cells in vitro would take the field of hematology a step ahead in translational medicine.

Cryopreservation as a Key Element in the Successful Delivery of Cell-Based Therapies-A Review

Cryopreservation is a key enabling technology in regenerative medicine that provides stable and secure extended cell storage for primary tissue isolates and constructs and prepared cell preparations. The essential detail of the process as it can be applied to cell-based therapies is set out in this review, covering tissue and cell isolation, cryoprotection, cooling and freezing, frozen storage and transport, thawing, and recovery. The aim is to provide clinical scientists with an overview of the benefits and difficulties associated with cryopreservation to assist them with problem resolution in their routine work, or to enable them to consider future involvement in cryopreservative procedures. It is also intended to facilitate networking between clinicians and cryo-researchers to review difficulties and problems to advance protocol optimization and innovative design.

Automated dry thawing of cryopreserved haematopoietic cells is not adversely influenced by cryostorage time, patient age or gender

Cell therapies are becoming increasingly widely used, and their production and cryopreservation should take place under tightly controlled GMP conditions, with minimal batch-to-batch variation. One potential source of variation is in the thawing of cryopreserved samples, typically carried out in water baths. This study looks at an alternative, dry thawing, to minimise variability in the thawing of a cryopreserved cell therapy, and compares the cellular outcome on thaw. Factors such as storage time, patient age, and gender are considered in terms of cryopreservation and thawing outcomes. Cryopreserved leukapheresis samples from 41 donors, frozen by the same protocol and stored for up to 17 years, have been thawed using automated, water-free equipment and by conventional wet thawing using a water bath. Post-thaw viability, assessed by both trypan blue and flow cytometry, showed no significant differences between the techniques. Similarly, there was no negative effect of the duration of frozen storage, donor age at sample collection or donor gender on post-thaw viability using either thawing method. The implication of these results is that the cryopreservation protocol chosen initially remains robust and appropriate for use with a wide range of donors. The positive response of the samples to water-free thawing offers potential benefits for clinical situations by removing the subjective element inherent in water bath thawing and eliminating possible contamination issues.

Cryopreservation in 95% serum with 5% DMSO maintains colony formation and chondrogenic abilities in human synovial mesenchymal stem cells

Background

Synovial mesenchymal stem cells (MSCs) are an attractive cell source for cartilage and meniscus regeneration. The optimum cryopreservation medium has not been determined, but dimethylsulfoxide (DMSO) should be excluded, if possible, because of its toxicity. The purposes of our study were to examine the possible benefits of higher concentrations of serum and the effectiveness of 100% serum (without DMSO) for the cryopreservation of synovial MSCs.

Methods

Human synovium was harvested from the knees of four donors with osteoarthritis during total knee arthroplasty. Synovial MSCs (8 × 10⁵ cells) were suspended in 400 μL medium and used as a Time 0 control. The same number of synovial MSCs was also suspended in 400 μL α-MEM medium containing 10% fetal bovine serum (FBS) (5% DMSO, and 1% antibiotic), 95% FBS (and 5% DMSO), or 100% FBS (no DMSO) and cryopreserved at − 80 °C for 7 days. After thawing, the cell suspensions (1.5 μL; 3 × 10³ cells) were cultured in 60 cm² dishes for 14 days for colony formation assays. Additional 62.5 μL samples of cell suspensions (1.25 × 10⁵ cells) were added to tubes and cultured for 21 days for chondrogenesis assays.

Results

Colony numbers were significantly higher in the Time 0 and 95% FBS groups than in the 10% FBS group (n = 24). Colony numbers were much lower in the 100% FBS group than in the other three groups. The cell numbers per dish reflected the colony numbers. Cartilage pellet weights were significantly heavier in the 95% FBS group than in the 10% FBS group, whereas no difference was observed between the Time 0 and the 95% FBS groups (n = 24). No cartilage pellets formed at all in the 100% FBS group.

Conclusion

Synovial MSCs cryopreserved in 95% FBS with 5% DMSO maintained their colony formation and chondrogenic abilities to the same levels as observed in the cells before cryopreservation. Synovial MSCs cryopreserved in 100% FBS lost their colony formation and chondrogenic abilities.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2700-3) contains supplementary material, which is available to authorized users.

Mobilization and Collection of Peripheral Blood Stem Cells in Adults: Focus on Timing and Benchmarking

Peripheral blood stem cells (PBSCs) are preferentially used as a hematopoietic stem cell source for autologous blood stem cell transplantation (ABSCT) upon high-dose chemotherapy (HDT) in a variety of hemato-oncologic diseases. As a prerequisite, hematopoietic stem cells have to be mobilized into the peripheral blood (PB) and collected by leukapheresis (LP). Despite continuous improvements, e.g., the introduction of plerixafor, current challenges are the further optimization regarding the leukapheresis procedure, preventing collection failures, as well as benchmarking and harmonization of mobilization approaches between institutions.This chapter summarizes the current PBSC mobilization and collection approaches and is focusing on timely orchestration of mobilization therapy, granulocyte colony-stimulating factor (G-CSF) application, and peripheral blood (PB) CD34⁺ cell assessment. Moreover, strategies for prediction and performance assessment of the PBSC collection yield are discussed.

Dimethyl Sulfoxide (DMSO) Decreases Cell Proliferation and TNF-α, IFN-γ, and IL-2 Cytokines Production in Cultures of Peripheral Blood Lymphocytes

Dimethylsulfoxide (DMSO) is an amphipathic molecule composed of a polar domain characterized by the sulfinyl and two nonpolar methyl groups, for this reason it is able to solubilize polar and nonpolar substances and transpose hydrophobic barriers. DMSO is widely used to solubilize drugs of therapeutic applications and studies indicated that 10% v/v concentration did not modify culture viability when used to treat human peripheral blood mononuclear cells (PBMC). However, some DMSO concentrations could influence lymphocyte activation and present anti-inflammatory effects. Therefore, the objective of this study was to evaluate the effect of DMSO on lymphocyte activation parameters. Cell viability analysis, proliferation, and cytokine production were performed on PBMC from six healthy subjects by flow cytometry. The results indicated that 2.5% v/v DMSO concentrations did not modify lymphocytes viability. DMSO at 1% and 2% v/v concentrations reduced the relative proliferation index of lymphocytes and at 5% and 10% v/v concentrations reduced the percentage of total lymphocytes, cluster of differentiation 4⁺ (CD4⁺) T lymphocytes and CD8⁺ T lymphocytes interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) producers. Thus, it was concluded that DMSO has an in vitro anti-inflammatory effect by reducing lymphocyte activation demonstrated with proliferation reduction and the decrease of cytokine production.

Storage Duration of Autologous Stem Cell Preparations Has No Impact on Hematopoietic Recovery after Transplantation

Peripheral blood stem cells (PBSCs) are widely used for autologous blood stem cell transplantation (ABSCT). These cells must be stored for months or even years, usually at temperatures ≤-140°C, until their use. Although several in vitro studies on CD34⁺ viability and clonogenic assays of PBSCs after long-term storage have been reported, only a few publications have investigated the influence of long-term storage on in vivo hematopoietic reconstitution. In this study, we retrospectively analyzed hematopoietic recovery after storage of PBSCs via controlled-rate freezing (CRF) and cryostorage in 10% DMSO at ≤-140°C in 105 patients with multiple myeloma who received high-dose melphalan before ABSCT. Three groups of PBSC transplantation (n = 247) were delineated based on the storage period: short-term (≤12 months, n = 143), medium-term (>12 and ≤60 months, n = 75), and long-term storage (>60 months, n = 29). A neutrophil increase of ≥.5 × 10⁹/L in medium-term or long-term PBSC cryopreservation groups was observed at day 14 after ABSCT; this increase was comparable to patients who received briefly stored PBSCs (day 15). No negative effect of PBSC storage duration was observed on leucocyte or neutrophil reconstitution. Platelet reconstitutions of ≥20  × 10⁹/L and 50 × 10⁹/L were observed after median times of 10 to 11 and 13 to 14 days after ABSCT, respectively. No influence of PBSC storage duration on platelet recovery of ≥20  × 10⁹/L and ≥50 × 10⁹/L was observed in the 3 storage groups (P = .07, P = .32). The number of previous ABSCTs also had no significant impact upon hematopoietic reconstitution. In conclusion, these results indicate that long-term cryopreservation of PBSC products at vapor nitrogen temperature after CRF does not have a negative effect on hematopoietic recovery even after prolonged storage.

Variable resistance to freezing and thawing of CD34-positive stem cells and lymphocyte subpopulations in leukapheresis products

BACKGROUND AIMS

Leukapheresis products for hematopoietic stem cell transplantation can be cryopreserved for various indications. Although it is known that CD34(+) cells tolerate cryopreservation well, a significant loss of CD3(+) cells has been observed, which has been ascribed to several factors, including transport, storage conditions and granulocyte-colony stimulating factor (G-CSF) administration.

METHODS

To assess the tolerance of CD34(+) cells and lymphocyte subpopulations for cryopreservation and thawing, the post-thaw recoveries of CD34(+) cells, CD3(+)CD4(+) cells, CD3(+)CD8(+) cells, CD19(+) cells and CD16(+)CD56(+) cells were determined in 90 cryopreserved apheresis products, among which 65 were from G-CSF-mobilized donors, and 34 from unrelated donors that underwent transport before cryopreservation at our center. A controlled rate freezer and 5% dimethyl sulfoxide were used for cryopreservation.

RESULTS

We could detect statistically significant differences for CD34(+) cell recovery (93.0 ± 20.7%) when compared to CD3(+)CD4(+) cell (83.1 ± 15.4%, P = 0.014), and CD3(+)CD8(+) cell recovery (83.3 ± 13.9%, P = 0.001). Similarly, CD19(+) cell recovery (98.6 ± 15.1%) was higher than CD3(+)CD4(+) cell (P = 2.5 × 10(-7)) and CD3(+)CD8(+) cell recovery (P = 1.2 × 10(-8)). Post-thaw recovery rates of all cell populations were not impaired in G-CSF-mobilized products compared with non-mobilized products nor in unrelated compared with related donor products.

DISCUSSION

Our data suggest a lower tolerance of CD3(+) cells for cryopreservation and demonstrate that freezing-thawing resistance thawing is cell-specific and independent from other factors that affect post-thaw recovery of cryopreserved cells. Thus, a clinical consequence may be the monitoring of post-thaw CD3(+) cell doses of cryopreserved products, such as donor lymphocyte infusions.

Long-term experiences in cryopreservation of mobilized peripheral blood stem cells using a closed-bag system: a technology with potential for broader application

BACKGROUND

In several European countries, preparation of cellular products with open manufacturing systems as used for cryopreservation of peripheral blood stem cells (PBSCs) needs to be performed in a clean-room facility. However, this form of manufacturing is highly expensive and laborious. Thus, safe techniques providing improved efficacy regarding time and material, which are in accordance with legal requirements are highly desirable.

STUDY DESIGN AND METHODS

We have developed, validated, and applied a simple method for cryopreservation of PBSCs within a functionally closed-bag system using the closed cryo freeze prep set. This process fulfills good manufacturing practice requirements and allows for the cryopreservation of PBSCs without a clean-room facility. In addition to cryopreservation of PBSCs, we have recently successfully modified our system for processing, portioning, and cryopreservation of allogeneic donor lymphocytes.

RESULTS

Since 2010, cryopreservation of PBSCs using a closed-bag system has been performed in our facility on a routine basis and 210 patients and healthy donors have been included in this analysis. No significant reduction in viability of CD34+ cells and no process-related contamination were observed. Outcome of hematopoietic stem cell transplantation regarding time of engraftment and infectious complications is comparable to products manufactured in conventional clean-room facilities.

CONCLUSION

Our data confirm that cryopreservation of PBSCs within a functionally closed-bag system is safe, effective, and economical. Furthermore, the system has the potential to be extended to other manufacturing processes of cellular products.

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.