Blood stem cell collection: factors influencing the recovery of granulocyte-macrophage colony forming cells

Melphalan, prednisone, and thalidomide vs melphalan, prednisone, and lenalidomide (ECOG E1A06) in untreated multiple myeloma

This phase 3 trial (Eastern Cooperative Oncology Group [ECOG] E1A06) compared melphalan, prednisone, and thalidomide (MPT-T) with melphalan, prednisone, and lenalidomide (mPR-R) in patients with untreated multiple myeloma (MM). A noninferiority design was used, and inferiority was defined as a progression-free survival (PFS) hazard ratio (HR) of MPT-T/mPR-R ≤0.82. A total of 306 patients enrolled, with a median age of 75.7 years. Median follow-up was 40.7 months. Median time on therapy was 12.1 months and 23.1 months for the 46.6% of treated patients who received maintenance, with no differences by arm. Median PFS was 21 months on MPT-T and 18.7 months on mPR-R (HR, 0.84; 95% confidence interval, 0.64-1.09). Overall survival was 52.6 months (MPT-T) vs 47.7 months (mPR-R) (P = .476). Per-protocol response rates were 63.6% (MPT-T) and 59.9% (mPR-R) (P = .557). Grade ≥3 nonhematologic toxicity was 59.5% for MPT-T vs 40.0% for mPR-R (P = .001). Second malignancies were observed in 18 MPT-T patients vs 14 mPR-R patients. Quality-of-life analysis favored mPR-R by induction end (P = .007). Use of MPT-T or mPR-R in elderly patients with untreated MM demonstrates no statistical or clinically relevant differences in response rates, PFS, and OS; however, quality of life at end of induction was improved and lower toxicity reported with mPR-R. This trial was registered at www.clinicaltrials.gov as #NCT00602641.

Cryopreserved human haematopoietic stem cells retain engraftment potential after extended (5-14 years) cryostorage

Harvesting of stem cells during the early phases of treatment with no immediate intention to perform a stem cell transplant is becoming an increasingly common practice. Such "insurance" harvests are often stored for many years before being needed for transplant in a subsequent relapse. The effect of long-term cryostorage (5-14 years) on the viability and functional capacity of haematopoietic stem cells (HSCs) was investigated in 40 bone marrow and peripheral blood harvests using standard in vitro methods, the colony forming unit-granulocyte/macrophage (CFU-GM) assay and a single platform viable CD34(+) cell absolute count by flow cytometry. Forty percent of harvests had CD34(+) HSC counts of at least 0.7 x 10(6)/kg bodyweight and 85% had CFU-GM counts of at least 1.0 x 10(5)/kg bodyweight, these values representing our institutional minimum requirements for safe transplantation. Based on these results, it appears that HSC collections can remain adequate for safe transplantation after up to 14 years of cryostorage. However, as deterioration of HSC quality and viability may occur, some precautions may be warranted, namely harvesting higher than normal numbers of HSCs in collections intended for long-term storage and repeating in vitro assays on harvests after long-term storage prior to transplantation.

Isolation of endothelial cells and their progenitor cells from human peripheral blood

PURPOSE

We have developed techniques to isolate endothelial cell (EC) progenitors from human peripheral and umbilical cord blood.

METHODS

Human adult peripheral and umbilical cord blood monocytes were isolated by centrifugation, and progenitor cells were separated with the use of magnetic polystyrene beads that were coated with a monoclonal antibody specific for the CD34 cell-membrane antigen. Cells were propagated in selective media, and developing cultures were immunostained for CD31, CD34, factor VIII, and vascular endothelial growth factor cell receptors. ECs that developed were transfected with a gene for prourokinase and used to line ePTFE grafts, which were evaluated in vitro in a pulsatile flow system.

RESULTS

Umbilical cord monocyte cultures demonstrated colonies that resembled ECs at approximately 2 weeks, with growth being best supported by EC growth media plus 20% calf serum with iron. Immunostaining of colonies was positive for CD31 and factor VIII. After 18 days in culture, CD34(+) cells from adult peripheral blood were noted, which had the typical cobblestone appearance of ECs and immunostained positively for CD31 and factor VIII-related antigens. Cultures of umbilical cord-derived cells and adult peripheral blood-derived cells developed complex line formations within 1 week in culture that stained positively for vascular endothelial growth factor receptor-2. Urokinase-transfected ECs were shown to overexpress urokinase. Prosthetic grafts lined with transfected cells showed 87.33% +/- 4.97% cell adherence after 2 hours in a pulsatile flow system at clinically relevant shear stress.

CONCLUSION

We conclude that endothelial progenitor cells can be isolated from human adult peripheral and umbilical cord blood and developed into EC cultures as a source of cells for vascular graft seeding and gene therapy.

A comparative study of a new, fully automated procedure and the standard mononuclear cell program using the Cobe Spectra for peripheral blood stem cell collection

Recently, a completely automated procedure, the AutoPBSC program for the COBE Spectra cell separator, has been developed for peripheral blood stem cell harvest (PBSCH). We compared the performance of the AutoPBSC program with the standard mononuclear cell (MNC) program in the same patients and in a donor. Peripheral blood stem cells (PBSC) were collected from 3 patients or a donor alternately using the MNC program and the AutoPBSC program in a course of PBSC mobilization. Equal blood volume was processed from each patient (200 ml/kg) and a donor (150 ml/kg). We used a harvest volume of 3 ml and a chase volume of 7 ml in all AutoPBSC procedures. The procedure duration was almost equivalent for both programs. The volume of products was significantly lower in the AutoPBSC program (71 +/- 13 ml) than in the MNC program (183 +/- 30 ml). MNC yields were fewer, and total nucleated cell (TNC) and MNC collection efficiency was less for the AutoPBSC program compared to the MNC program. The CD34+ cell collection efficiency was less for the AutoPBSC program (26.5 +/- 13.7%, compared with 77.7 +/- 60.6%; p > 0.05). The contamination of platelets and red cells was significantly less in the AutoPBSC program than in the MNC program. In conclusion, we consider that the collection efficiency in the new program should be improved by modification of parameters because there exist great advantages to automated procedures.