The Use of Mobilized Peripheral Blood Stem Cells from Normal Donors for Allografting

Summary:We describe collection and purification of peripheral blood CD34 ؉ cells from volunteer, normal donors and allogeneic stem cell donors. A total of 98 aphereses were performed on 68 volunteer donors using peripheral venous access. The mean number of nucleated cells collected was 4.6 × 10 10 which included 1.9 × 10 8 CD34 ؉ cells corresponding to 2.7 × ilized PBPCs are now being used in related and unrelated allogeneic transplantation. Apheresis collection is well tolerated and is potentially less invasive than bone marrow harvest. Recently, attention has focused on the number of CD34 + cells in the PBPCs as the component responsible for the time to recovery after intensive chemotherapy and the cells likely responsible for long-term engraftment and reconstitution of hematopoiesis. 9-15 Therefore, an enriched population of CD34 + cells may be a superior donor product. In addition, isolation of CD34 + cells may decrease contaminating tumor cells, 16,17 deplete mature T cells for modulation of graft-versus-host disease [18][19][20] and provide the target of choice for both ex vivo expansion 21,22 and gene transfer. [23][24][25][26] Antibodies directed against the CD34 antigen have provided a means for rapidly purifying and concentrating CD34 + cells using immunomagnetic techniques. 27,28 Although apheresis devices have been shown to be effective for collecting large numbers of nucleated white blood cells, the number of CD34 + cells collected is highly variable depending on factors such as the individual's response to cytokine and the number of blood volumes processed. 29,30 Reliable predictors of CD34 + cell purity, recovery, and clonogenic potential are currently needed and would be advantageous in planning efficient use of growth factor during mobilization and minimizing procedural discomfort to the donor.Although there is a large experience with apheresis from patients on cytotoxic therapeutic regimens, limited data are available from normal volunteers on the safety, efficacy and ability to collect purified CD34 + cells. We present the results of a large series of aphereses (n = 98) and CD34 + cell isolations using the Isolex 300i magnetic separator (n = 30) on G-CSF-mobilized PBPCs from normal volunteers. Adverse events, absolute numbers of cells collected, and CD34 + cell purification are presented. In addition, we present results from 38 CD34 + cell isolations using the Isolex 300i performed on normal allogeneic stem cell donors. These data provide further evidence for the safety and feasibility of collecting adequate numbers of CD34 + cells from the peripheral blood of normal donors for stem cell support, transplantation and gene therapy.

Section: Discussionsupporting

confidence: 69%

Large-scale mobilization and isolation of CD34+ cells from normal donors

Croop

Cooper

Seshadri

et al. 2000

“…30 In 1997, Anderlini & Körbling assumed a more primitive phenotype of CD34 + cells contained in PBSC compared with BM. 25 Furthermore, they postulated a faster engraftment after PBSC transplantation compared with BM allografting as described before. 26 This was later confirmed by different authors, who reported no differences in both overall and event-free survival between PBSC and BM, but observed a clearly faster neutrophil and platelet engraftment after infusion of PBSC.…”

Section: Discussionmentioning

confidence: 80%

“…This may be the reason for the more rapid sustained engraftment after infusion of PBSC instead of BM. 25,26 In BM1y, these earlier CD34 subtypes are again significantly lower than in BMd. In contrast, the more committed CD34 stages, that is, MLP and particularly BLP, are significantly higher in BM1y than in BMd, whereas they are hardly present in PBSC.…”

Section: Discussionmentioning

confidence: 87%

Multi-color immune-phenotyping of CD34 subsets reveals unexpected differences between various stem cell sources

Dmytrus

Matthes‐Martin

Pichler

et al. 2016

Flow cytometric routine CD34 analysis enumerates hematopoietic stem and progenitor cells irrespective of their subpopulations although this might predict engraftment dynamics and immune reconstitution. We established a multi-color CD34 assay containing CD133, CD45RA, CD10, CD38 and CD33. We examined PBSC, donor bone marrow (BMd) and BM of patients 1 year after allografting (BM1y) regarding their CD34 subset composition, which differed significantly amongst those materials: the early CD45RA − CD133 + CD38 low subpopulations were significantly more frequent in PBSC than in BMd, and very low in BM1y. Vice versa, clearly more committed CD34 stages prevailed in BM, particularly in BM1y where the proportion of multi-lymphoid and CD38 ++ B-lymphoid precursors was highest (mean 59%). CD33 was expressed at different intensity on CD45RA ± CD133 ± subsets allowing discrimination of earlier from more committed myeloid precursors. Compared with conventional CD34 + cell enumeration, the presented multicolor phenotyping is a qualitative approach defining different CD34 subtypes in any CD34 source. Its potential impact to predict engraftment kinetics and immune reconstitution has to be evaluated in future studies.

“…[6][7][8][9] As many patients receiving relatively small doses of CD34 þ cells show adequate engraftment, the importance of the composition of the PBPC allograft has received only limited attention. [10][11][12][13] The effect of the composition of the PBPC grafts from MRDs and from MUDs on hematologic recovery of the patents was studied, with particular attention to the differences between MRD and MUD grafts.…”

Section: Introductionmentioning

confidence: 99%

Slow platelet recovery after PBPC transplantation from unrelated donors

Jansen

Hanks

Akard

et al. 2008

The effects of the composition of PBPC grafts from matched related donors (MRDs) and matched unrelated donors (MUDs) have not been compared. In a single-center study, the compositions of 55 MRD PBPC grafts and 33 MUD grafts were studied for their effect on the rate of engraftment in patients who had evidence of donor cell engraftment on day þ 28. The MUD grafts came more frequently from young male donors and contained more CD34 þ cells but similar numbers of colony-forming units granulocyte-macrophage (CFU-GM) and burst forming units-erythroid. The recovery of neutrophils to 4500/mm 3 was equally fast in both groups, but recovery of platelets to 420 000/mm 3 was significantly delayed in the MUD group (Po0.001). The MUD group also required more transfusions of platelets and red cells. Patients receiving grafts containing low numbers of CFU-GM had markedly delayed platelet recovery. The patients with the slowest engraftment tended to have prolonged transportation times. Storage experiments suggested a major loss of viable CD34 þ cells and CFU-GM when undiluted PBPC products are stored at room temperature. The data suggest that a fraction of the MUD grafts suffer during transportation. In vitro proliferation assays should be part of the validation and auditing of transportation of MUD grafts.