High-dose melphalan followed by autograft employing non-cryopreserved peripheral blood progenitor cells in children

Long-term storage of peripheral blood stem cells frozen and stored with a conventional liquid nitrogen technique compared with cells frozen and stored in a mechanical freezer

BACKGROUND

Cryopreservation of hematopoietic progenitor cells using liquid nitrogen and controlled-rate freezing requires complex equipment and highly trained staff and is expensive. We compared the liquid nitrogen method with methods using a combination of dimethyl sulfoxide (DMSO) and hydroxyethyl starch (HES) for cryopreservation followed by storage in mechanical freezers.

STUDY DESIGN AND METHODS

Peripheral blood stem cells (PBSCs) were collected from normal donors by apheresis and allocated to one of four preservation and storage conditions: 1) 10% DMSO with freezing in liquid nitrogen and storage in liquid nitrogen, 2) 5% DMSO and 6% HES with freezing and storage in a -80 degrees C mechanical freezer, 3) 5% DMSO and 6% HES with freezing in a -80 degrees C mechanical freezer and storage in a -135 degrees C mechanical freezer, or 4) 5% DMSO and 6% HES with freezing and storage both in a 135 degrees C mechanical freezer. Cells were stored for 5 years during which total nucleated cells (TNCs), cell viability, CD34+ cell content, and colony-forming unit-granulocyte-macrophage content were determined.

RESULTS

There were some significant differences in the variables measured during freezing and the 5 years of storage compared to the values before freezing and storage; however, these differences were not consistent and do not favor one protocol over the others. Samples stored for 24 hours before cryopreservation showed a significant decrease in TNCs, but no other significant changes during the 5 years.

CONCLUSION

In vitro measurements indicate that PBSCs can be successfully frozen and stored using a combination of DMSO and HES providing smaller amounts of DMSO and allowing simplified freezing and storage conditions.

Feasibility and safety of autotransplants with noncryopreserved marrow or peripheral blood stem cells: a systematic review

The objective of this systematic review is to examine the feasibility and safety of autologous noncryopreserved stem-cell transplants. This technique avoids the cost of establishing and maintaining a cryopreservation facility and may be of value for transplant centers in regions with limited economic resources. The primary outcome was the graft failure rate. In addition, a detailed description of the high-dose therapy regimens employed was undertaken. Secondary outcomes were transplant-related mortality and neutrophil and platelet engraftments times. Sixteen well-conducted nonrandomized studies met the eligibility criteria. Only two cases of graft failure (0.36%) occurred among 560 assessable patients receiving high-dose therapy and autotransplant for non-Hodgkin's lymphoma, Hodgkin's lymphoma, multiple myeloma, germ-cell tumors and acute leukemias. The most traditional high-dose schedules were used, although often modified to shorter regimens. High-dose melphalan appeared especially useful given its short half-life and was used to treat multiple myeloma by most groups. Secondary outcomes were comparable to those reported in the most relevant studies addressing standard (cryopreserved) autotransplant. According to this study, the use of autologous noncryopreserved hematopoietic progenitors to support patients undergoing high-dose therapy is feasible and safe.

Short-term liquid storage of umbilical cord blood

BACKGROUND

Processing and banking of umbilical cord blood requires the development of methods for short-term liquid storage. This study examines the conditions (temperature, time, and storage solution) for optimal storage of cord blood.

STUDY DESIGN AND METHODS

Cord blood obtained from normal donors was collected and divided into aliquots. Some of the aliquots were supplemented with a storage solution and undiluted cord blood was used as a control. MNC counts, percentage of cells that are CD34+45+, frequency of CFU-GM, and solution pH were monitored for up to 72 hours in storage at 4 degrees C and room temperature.

RESULTS

MNC counts, CD34+45+ cell recovery, and frequency of CFU-GM were all improved in samples diluted with a storage medium when compared to undiluted controls. MNC counts were higher when cells were stored at 4 degrees C. MNC counts and the frequency of CFU-GM were reduced at 72 hours when compared with 24 hours.

CONCLUSIONS

These results indicate that the recovery of cells from cord blood can be improved if samples are stored using a storage solution for 24 hours without significant cell losses. Some of the solutions determined to be effective in maintaining viability are approved for human applications, although not specifically cord blood preservation.

Cryopreservation of cord blood after liquid storage

BACKGROUND

The processing of cord blood may result in delays prior to RBC depletion and cryopreservation. The overall objective of this investigation is to determine the influence of liquid storage prior to cryopreservation on the post-thaw viability.

METHODS

UC blood supplemented with CPD anticoagulant (CB) was obtained from normal donors with informed consent. CB was stored undiluted, or diluted with 1:1 ratio of storage solution STM-sav for up to 72 h. The undiluted control samples were stored at room temperature. CB samples supplemented with STM-sav were stored at 4 degrees C. After completion of the storage protocol, the sample was RBC depleted, frozen, stored, thawed, and assayed for viability. Nucleated cell counts, percentage of CD34+ cells, and frequency of colony formation were determined during liquid storage and after cryopreservation.

RESULTS

The post-thaw mononuclear cell recovery and viability of cord blood stored for 72 h was significantly lower than that of cord blood stored for 24 h prior to cryopreservation. This difference was true for cord bloods stored in STM-sav and controls. Dilution of the cord blood with STM-sav improved the frequency of CFU-GM observed.

DISCUSSION

Liquid storage of cord blood for 24 h prior to cryopreservation does not adversely influence the post-thaw cell recovery. The use of a storage solution (STM-Sav) enhances the retention of colony-forming capabilities post-thaw. These and other studies provide an important foundation for the development of integrated protocols for cord blood banking.

Early apoptosis largely accounts for functional impairment of CD34+ cells in frozen-thawed stem cell grafts

Quality assessment of stem cell grafts is usually performed by flow cytometric CD34(+) enumeration or assessment of clonogenic output of fresh material. Previously, we identified the occurrence of early apoptosis, not detectable with the permeability marker 7-amino actinomycin D (7-AAD), in purified frozen-thawed CD34(+) cells, using the vital stain Syto16. Syto(high)/7-AAD(-) cells were defined as viable, Syto16(low)/7-AAD(-) cells as early apoptotic and Syto16(low)/7-AAD(+) as dead. This was confirmed in a subsequent study using frozen-thawed transplants of lymphoma patients. In the present study on grafts from multiple myeloma and lymphoma patients, we investigated the functional consequences of the early apoptotic process. The mean Syto16-defined viability was 41 and 42%, respectively, for both graft groups, compared to 78% and 72%, respectively, using 7-AAD only. The established early apoptosis marker annexin V missed roughly 50% of the early apoptosis detected with Syto16. In contrast, viability of CD34(+) cells in nonmanipulated whole blood transplants from a matched group of lymphoma patients, after 72 h of storage at 4 degrees C, was more than 90%, even with the Syto16 assay. CFU recovery (median 26-33%) after cryopreservation matched CD34(+) recovery after Syto16, but not 7-AAD correction. In contrast, colony-forming unit (CFU) recovery in the whole blood transplant was close to 100%. Furthermore, early apoptotic CD34(+) cells had lost migratory ability toward stromal cell derived factor-1alpha (SDF-1alpha). The establishment of a Syto16(high)/7-AAD(-) proportion of CD34(+) cells offers a new approach for a more correct determination of the number of viable nonapoptotic CD34(+) cells in stem cell grafts. Further development of this assay should allow its incorporation into the routine CD34(+) assessment of post-thawed samples in clinical flow cytometry laboratories.

Extensive early apoptosis in frozen-thawed CD34-positive stem cells decreases threshold doses for haematological recovery after autologous peripheral blood progenitor cell transplantation

Stem cell doses necessary for engraftment after myelo-ablative therapy as defined for fresh transplants vary largely. Loss of CD34+ cell quality after cryopreservation might contribute to this variation. With a new early apoptosis assay including the vital stain Syto16, together with the permeability marker 7-AAD, CD34+ cell viability in leucapheresis samples of 49 lymphoma patients receiving a BEAM regimen was analysed. After freeze-thawing large numbers of non-viable, early apoptotic cells appeared, leading to only 42% viability compared to 72% using 7-AAD only. Based on this Syto16 staining in the frozen-thawed grafts, threshold numbers for adequate haematological recovery of 2.8-3.0 x 10(6) CD34+ cells/kg body weight determined for fresh grafts, now decreased to 1.2-1.3 x 10(6) CD34+ cells/kg. In whole blood transplantation of lymphoma patients (n = 45) receiving a BEAM-like regimen, low doses of CD34+ cells were sufficient for recovery (0.3-0.4 x 10(6)CD34+ cells/kg). In contrast to freeze-thawing of leucapheresis material, a high viability of CD34+ cells was preserved during storage for 3 days at 4 degrees C, leaving threshold doses for recovery unchanged. In conclusion, the Syto16 assay reveals the presence of many more non-functional stem cells in frozen-thawed transplants than presumed thus far. This led to a factor 2.3-fold adjustment downward of viable CD34+ threshold doses for haematological recovery.

Non-cryopreserved peripheral blood progenitor cells collected by a single very large-volume leukapheresis: a simplified and effective procedure for support of high-dose chemotherapy

High-dose chemotherapy with autologous peripheral blood progenitor cell (PBPC) support has become a widely used treatment strategy. In order to simplify the procedure, a single very large-volume leukapheresis programme combined with short-term refrigerated storage of the PBPC was developed. Seventy-two patients suffering from various relatively chemosensitive malignancies received high-dose chemotherapy, consisting of agents with short in vivo half-lives and 24 to 48 hours later, the refrigerated PBPC were reinfused. A single very large-volume apheresis was sufficient to obtain at least 2 x 10(6)/kg CD34+ cells in 58 patients (81%), and 63% had at least 2.5 x 10(6) CD34+ cells/kg. Only two patients (3%) were transplanted with less than 1 x 10(6) CD34+ cells/kg. In three patients (4%) leukapheresis was repeated because of insufficient number of PBPC. The median CD34+ cell count was 3 x 10(6)/kg. A median of 38.5 L blood (range, 21 to 59) was processed, which accounted for a median of 9 x patient's total blood volume. Very large-volume leukapharesis was well tolerated with symptomatic hypocalcemia being the most common (18%) side-effect. The median time to neutrophils >1.5 x 10(9)/L, and to self-supporting platelet count >25 x 10(9)/L, was 10 and 12 days after reinfusion of PBPC graft, respectively. There were no treatment-related deaths. Our results indicate that this simplified approach of PBPC transplantation can be associated with prompt hematologic recovery in most patients and that it can be useful in settings where facilities are limited or for certain diseases where conditioning regimens with short half-life are appropriate. J. Clin. Apheresis, 15:236-241, 2000.

Feasibility and safety of peripheral blood stem cell collection in children with poor-prognosis solid tumors: a single center experience

This study reports the data of 32 children with poor-prognosis solid tumors who had 78 PBSC harvests on Fenwall CS-3000plus after mobilization mainly by different treatment protocol chemotherapy regimens followed by G- or GM-CSF (92% of patients) or by G-/GM-CSF alone (8%). Timing of procedure was predicted by studying the blood count. When the white blood cell and platelet count reached a median of 8.1 (0.9-37.3) and 95 (16-338) x 10(9)/L, respectively, the median number of 2.7 (0.005-16.8) x 10(6) CD34+/kg with 1.5 (0.005-11.6) x 10(6) CD34+/kg for 1 blood volume processed was obtained per procedure. In the group of 13 patients with low body weight (median 14 [10-20] kg) 32 leukophereses were performed. The extracorporal line was primed with donor red blood cells in the patients with the weight below 15 kg. No difference was observed in CD34+ content in harvests whether GM-CSF was begun on day +1 or on day +3 after chemotherapy.