摘要:

AbstractAttempted human allogeneic marrow transplants in the 1950s and 60s were largely unsuccessful. In the past two decades the probability of success has improved steadily depending on the type and stage of disease. Cure rates range from about 90% for nonmalignant diseases transplanted early to 15% for patients with advanced leukemia. Most marrow transplants have involved an HLA matched sibling donor but, more recently, through the National Marrow Donor Program, a matched unrelated volunteer marrow donor can be found for many patients without a family donor. Current research involves new preparative regimens for elimination of malignant cells, better prevention of graft‐versus‐host disease, and the use of hematopoietic growth factors and cytokines. Autologous transplants, which use the patient's own marrow, are increasing. The hematopoietic stem cell, which is responsible for marrow regeneration after a transplant, has been isolated and characterized. Stem cells for transplantation can now be obtained from the peripheral blood after mobilization of these cells by chemotherapy or hematopoietic growth factors. A variety of technological advances makes it possible to perform transplants with less time in the hospital and a corresponding saving in c

ISSN:1066-5099    

DOI:10.1002/stem.5530120602

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn this review four parameters relevant to the grafting of hemopoietic stem cells (HSC) are analyzed: the nature and amounts of grafted HSC, the sources of HSC and the “in vivo” fate of the grafted cells. One may oppose cells with short‐term repopulating ability to cells with long‐term reconstitutive capacity. The former comprise progenitors, while the latter consist of primitive stem cells, corresponding to murine pre‐colony forming units‐spleen (pre‐CFU‐S) (and to some murine CFU‐S) or to human pre‐colony forming units (pre‐CFU). In the mouse, the number of progenitors involved in short‐term reconstitution is large, while that of primitive cells operating months after the transplantation is reduced. These results may be extrapolated to humans, suggesting that it is possible to engraft a limited number of genetically modified HSC. However, the administration of large numbers of reconstituting cells appears to be a cautionary procedure, since it should insure polyclonal hemopoiesis, which is the physiological situation in mammals. Besides marrow, peripheral blood from adult patients treated with chemotherapy and growth factors, and cord blood from newborns, are promising sources of HSC. Successful engraftment depends not only on the quality and quantity of HSC, but also on the integrity of the marrow microenvironment. This microenvironment may be impaired by chemo‐ and radiotherapy, which provides a theoretical basis for the transplantation of stromal cel

ISSN:1066-5099    

DOI:10.1002/stem.5530120603

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractGene transfer to hematopoietic cells for the purpose of “gene therapy” is a new and rapidly developing field with clinical trials in progress. A fundamental goal of research in this field is the incorporation of exogenous genes into the chromosomes of the most primitive hematopoietic progenitor cells—stem cells. Recombinantly engineered retroviral vectors are the best characterized and are currently the only vector type in clinical trials directed at the hematopoietic system. High efficiency gene transfer and expression in murine stem cells and their progeny is now routine, but in larger animal models such as dogs or primates and preliminary clinical trials, gene transfer has been less successful. Problems such as retroviral efficiency, gene expression, insertional mutagenesis and helper virus contamination are being addressed. A promising new vector, the adeno‐associated virus (AAV), has shown promise and may allow production of high titer, stable, recombinant virions without helper contamination and with potentially better safety parameters. However, the technology for AAV gene transfer is currently underdeveloped, and issues related to the reproducible production of vectors must be addressed. Other non‐viral vector systems are being explored, but little data are available on applications to hematopoietic cells. Better preclinical models are needed to study gene targeting and expression in human cells. An overview of recombinant retroviral and adeno‐associated viral vector production, preclinical data and preliminary clinical data will be given, and problems needing to be addressed at all stages of development before broad clinical utility can be achieved will b

ISSN:1066-5099    

DOI:10.1002/stem.5530120604

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe CD34 antigen is expressed by early hematopoietic stem cells and progenitors and is detected on the surface of approximately 1% of bone marrow mononuclear cells [1‐3]. Several monoclonal antibody‐based methods have been developed to isolate these cells from clinical samples of bone marrow or peripheral blood based on their expression of this antigen, utilizing either biotin‐avidin affinity, panning or immunomagnetic beads. Roughly 50% of CD34+cells, with 20‐90% purity, are recovered from clinical samples using these methods. Several clinical trials have demonstrated hematopoietic recovery using CD34+selected cells to support high dose therapy. CD34+cells may be useful in several areas of clinical stem cell transplantation, including purging of tumor cells, T cell depletion, stem cell expansion and gene therapy. This paper reviews the current methods for purification of CD34+cells from clinical samples and discusses potential uses of these cells in transpla

ISSN:1066-5099    

DOI:10.1002/stem.5530120605

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractPlatelets, an integral component of hemostasis, are produced by megakaryocytes derived from the differentiation of pluripotent stem cells in the bone marrow or spleen. After decades of study, the regulation of this process is still not well understood. However, the recent cloning and characterization of thrombopoietin, a ligand for the receptor encoded by the c‐mplproto‐oncogene, provides new insights into the humoral regulation of megakaryocytopoiesis and platelet production. Consistent with the proposed role as a major physiological regulator of megakaryocytopoiesis, thrombopoietin has potent effects on megakaryocytopoiesis in vitro and in vivo. In addition to the original supposition that thrombopoietin functions as a late‐acting megakaryocyte maturation factor, recombinant thrombopoietin proves also to be a potent stimulator of hematopoietic progenitor cells, inducing them to undergo proliferation and differentiation into megakaryocytic colonies. When administered to mice, thrombopoietin causes an increase in peripheral platelet numbers to previously unattainable levels within a few days. Studies of the efficacy of thrombopoietin are underway. It is envisaged that this new cytokine will have widespread applications as a therapeutic agent for the management of bleeding due to thrombocytopenias, in particular those resulting from cancer chemo‐ or irradiation

ISSN:1066-5099    

DOI:10.1002/stem.5530120606

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractStimulating CD34+hematopoietic cells with growth factors prior to transplantation may decrease the duration of post‐transplant aplasia. The optimal time in which to deliver this stimulus remains unclear. We therefore sought to determine if progenitor cell cloning efficiency, as reflected by colony forming units‐granulocytemacrophage (CFU‐GM) colony formation, differed when growth factor stimulation was carried out prior to freezing or after thawing. To address this issue, CD34+marrow cells were suspended in Iscove's medium with 20% bovine calf serum. They were then stimulated withkitligand (KL), interleukin‐3 (IL‐3), and interleukin‐1β (IL‐1β) for 36 h either prior to cryopreservation or immediately after thawing. We observed that cells stimulated prior to freezing formed more CFU‐GM colonies than cells stimulated after thawing. We also found that CD34+cells stimulated with growth factors either before or after freezing gave rise to more CFU‐GM colonies than thawed cells plated without prestimulation. Thus, the cloning efficiency of stored marrow, as reflected by CFU‐GM colony formation, may be effectively enhanced by pretreating cells with hematopoietic growth factors. Our data further suggest that the optimal time for this treatment is before cryopreservation as opposed to immediately after thawing. Based on these results, we hypothesize that stimulation of CD34+hematopoietic cells prior to cryopreservation may simplify cell processing, enhance subsequent engraftment, and bring about significant cost savings by decreasing the amounts of recombinant growth factors administered to patients in order to facil

ISSN:1066-5099    

DOI:10.1002/stem.5530120607

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractTen patients with aplastic anemia (AA) and seven patients with refractory anemia (RA) were treated with recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) and erythropoietin (rhEpo) in combination. rhG‐CSF (5‐20 μg/kg) and rhEpo (120‐720 U/kg) were administered by s.c. injection three times a week for at least six months, and the administration was continued as maintenance therapy for as long as possible when hematological responses were observed. Six (60%) of the ten AA patients and four (58%) of the seven RA patients showed multilineage responses. Of these responders, six patients achieved trilineage recovery. While all of the responders were dependent on red blood cell transfusions and eight of them required platelet transfusions before treatment, they now no longer need transfusions of either red blood cells or platelets. A median treatment duration of 9 (range 1 to 28) months was required to achieve multilineage recovery. The responders showed an ability to maintain the multilineage recovery for 9+ to 47+ months and to tolerate long‐term treatment. These results indicate that the long‐term treatment with rhG‐CSF and rhEpo may benefit a substantial percentage of patients with AA and RA and provide an optional therapy fo

ISSN:1066-5099    

DOI:10.1002/stem.5530120608

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractWe evaluated the growth of cord blood myeloid progenitors or colony forming units granulocyte‐macrophage (CFU‐GM) and their response to various recombinant growth factors or colony stimulating factors (CSFs): interleukin 3 (IL‐3), IL‐6, granulocyte‐macrophage CSF (GM‐CSF) and stem cell factor (SCF). Using classical stimulant (human placenta conditioned medium or HPCM), we observed a significantly higher day‐14/day‐7 CFU‐GM ratio in CB than in bone marrow (BM). The association of IL‐3, IL‐6, GM‐CSF and SCF induced significantly more CB day‐14 CFU‐GM than HPCM. This effect is significantly greater in CB than in bone marrow. Since fetal calf serum (FCS) is known to contain inhibitors, we have compared the ability of CSFs to induce CFU‐GM formation in FCS‐supplemented and FCS‐free culture. In CB, using HPCM, we obtained significantly more CFU‐GM in FCS‐free medium than in FCS‐supplemented medium. This difference was corrected by the addition of anti‐transforming growth factor‐β (TGF‐β) neutralizing antibody. However, with the association of the four CSFs, no significant difference between FCS and FCS‐free culture was observed. In conclusion: a) day‐14/day‐7 CFU‐GM ratio was higher in CB than in BM indicating that CB CFU‐GM are more primitive than BM CFU‐GM; b) FCS can be successfully replaced by serum‐free medium; c) FCS contains inhibitors of day‐14 CFU‐GM and among them TGF‐β; and d) the association IL‐3, SCF, GM‐

ISSN:1066-5099    

DOI:10.1002/stem.5530120609

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThere is increasing clinical interest focused on ex vivo manipulation and expansion of hematopoietic cells. In this study, we demonstrate that a simple combination of growth factors can expand progenitors to yield functional myeloid cells. Furthermore, this system can produce mature, functionally competent cells in the absence of fetal bovine serum (FBS), which will enhance the clinical utility of this approach.Hematopoietic progenitor cells obtained from normal bone marrow and from leukapheresis products were studied. The mononuclear fraction was enriched for CD34 cells using the Ceprate CD34 biotin kit (CellPro #LC34‐1 or LC34‐2). The selected cells were expanded for two weeks in Iscove's medium supplemented with 20% FBS and various combinations of interleukin‐3 (IL‐3), granulocyte colony‐stimulating factor (G‐CSF), stem cell factor (SCF) and interleukin‐6 (IL‐6) added either simultaneously or sequentially. The optimal combination of these factors identified for myeloid expansion was simultaneous addition of IL‐3, SCF and G‐CSF (at 50 ng/ml each), resulting in an average 773 ± 133‐fold expansion of nucleated cells (n = 5). When corrected for the purity of CD34 cells in the starting population, the mean fold expansion with IL‐3, SCF and G‐CSF was 2,265 ± 729. A mean of 74.7 ± 10.5% (n = 3) of the expanded cells was positive for CD11b; 86‐91% (n = 2) of the cells were promyelocytes or more mature granulocytes. Functional assays demonstrated normal phagocytosis and intracellular killing ofStaphylococcus aureus (S. aureus)by the expanded cell population.Studies performed using cells expanded in defined serum‐free media demonstrated that fold expansion was decreased and that the cells produced were less mature and functionally less competent than cells expanded with FBS. The decreased expansion could be partially reversed, and the functionality almost completely restored by t

ISSN:1066-5099    

DOI:10.1002/stem.5530120610

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractTo investigate the functional activity of interleukin 4 (IL‐4) on human marrow stroma formation, normal bone marrow (BM) samples were cultured in “Dexter‐type” long‐term cultures in the presence and absence of IL‐4. IL‐4 (0.001 to 1.0 μg/ml) added at the initiation of culture and once weekly when the cultures were fed effaced the culture architecture. In four‐week old confluent cultures smooth muscle‐like and endothelial‐like cells were rare, the fibronectin network and cobblestone areas were absent, and a preponderance of monocyte‐macrophages characterized the adherent layer. Exposure to IL‐4 reduced the numbers of CD34+cells, colony‐forming unit granulocyte‐macrophage (GFU‐GM) cells and burst‐forming unit‐erythroid (BFU‐E) cells in the adherent layer, and increased their numbers in the nonadherent layer. In five of eight IL‐4‐containing cultures the concentrations of macrophage colony‐stimulating factor (M‐CSF) were increased and in two of eight IL‐4‐treated cultures the concentrations of tumor necrosis factor‐α (TNF‐α) were significantly elevated as compared to those in control cultures, whereas there were no consistent differences in the levels of either IL‐6 or transforming growth factor‐β (TGF‐β). IL‐1β and granulocyte‐macrophage CSF (GM‐CSF) were not detected in any culture. These data suggest that IL‐4 suppre

ISSN:1066-5099    

DOI:10.1002/stem.5530120611

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY