Allogeneic hematopoietic stem cell transplantation: from the nuclear age into the twenty-first century.
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Animals↗
Biomedical subjects
R Storb
Publications and source records attributed to R Storb.
Changing from cyclosporine to tacrolimus as salvage therapy for chronic graft-versus-host disease.
Chronic graft-versus-host disease (GVHD) is the principal cause of transplantation-related morbidity and nonrelapse mortality late after allogeneic hematopoietic stem cell transplantation. The safety and potential efficacy of tacrolimus for the salvage treatment of chronic GVHD was evaluated in a single-arm, open-label phase 2 study. A total of 39 evaluable patients with chronic GVHD who failed previous immunosuppressive therapy with cyclosporine and prednisone were treated with tacrolimus starting at a median of 20 months (range, 3-68 months) after transplantation. At 3 years after the start of treatment, 5 patients (13%) had discontinued tacrolimus and were in complete remission, and 3 were considered clinically stable but not able to discontinue tacrolimus. A total of 31 patients (79%) experienced treatment failure; 22 (56%) who failed therapy had a change in immunosuppressive regimen because of progression (n = 18) or toxicity (n = 4). Nine patients (23%) died during continued treatment with tacrolimus. Two patients were lost to follow-up, at 11 and 19 months. The median duration of treatment with tacrolimus was 9 months (range, 1-29 months). Infections (144 episodes) were the most frequent adverse event. Nephrotoxicity occurred in 16 patients (41%); tacrolimus was discontinued in only 2 patients because of progressive deterioration in renal function. The Kaplan-Meier estimate of survival was 64% (95% confidence interval, 49%-79%) at 3 years posttransplantation. Seven patients had discontinued all immunosuppression at last contact, leading to an estimated 29% probability of stopping all immunosuppression by 3 years posttransplantation. Four patients died after relapse of malignancy. The response rate is consistent with previous reports of salvage treatment for chronic GVHD, indicating that a small group of patients failing cyclosporine may respond or stabilize with tacrolimus.
Adolescent↗
De novo chronic graft-versus-host disease in marrow graft recipients given methotrexate and cyclosporine: risk factors and survival.
A retrospective study was performed to determine risk factors for the development of de novo chronic graft-versus-host disease (GVHD) in patients given marrow grafts from HLA-identical sibling donors (85%), HLA-nonidentical family members (3%), or HLA-matched unrelated donors (12%) and for postgrafting immunosuppression with methotrexate and cyclosporine. We also examined the impact of chronic GVHD on survival and identified patients at low risk for chronic GVHD in whom immunosuppression might be stopped safely early after transplantation. Among 489 patients with either grade 0 or I acute GVHD, 33% developed chronic GVHD. Overall survival was 70%, and relapse-free survival was 63% at 8 years. Risk factors for chronic GVHD were found to include donor buffy coat infusions among patients given transplants for aplastic anemia (relative risk [RR] = 2.9, P = .05), patient-donor sex/parity combination (likelihood ratio test, P < .001), grade I acute GVHD (RR = 1.6, P = .003), and active cytomegalovirus infection (RR = 1.5, P = .05) before day 60. Among 45 patients aged <19 years who had male donors, only 1 developed chronic GVHD. This group had an overall survival rate of 65% and a relapse-free survival rate of 54% at 8 years post-transplantation-a result not better than that among the entire cohort. The lack of improvement in survival in the low-risk group was related to a high rate of relapse of the underlying diseases. Therefore, the development of de novo chronic GVHD does not have a negative impact on patient survival; the adverse effect from increased transplantation-related complications is offset by a lower relapse rate, the result of an allogeneic graft-versus-tumor effect.
Adolescent↗
Granulocyte colony-stimulating factor given to donors before apheresis does not prevent aplasia in patients treated with donor leukocyte infusion for recurrent chronic myeloid leukemia after bone marrow transplantation.
We conducted 2 sequential studies of donor leukocyte infusion (DLI) in 26 patients with chronic myeloid leukemia in hematologic relapse after unmodified allogeneic bone marrow transplantation. In the first study, cells for DLI were collected from 13 donors who were not treated with granulocyte colony-stimulating factor (G-CSF) (group 1). In the second study, cells were collected from 13 donors who received G-CSF before apheresis (group 2) in an attempt to avoid aplasia after DLI. Patients in group 2 received 550-fold more CD34+ cells than those in group 1. We found no significant difference in the incidence (31% versus 22%), onset time (41 vs. 48 days), or duration (15 vs. 14 days) of cytopenia after DLI in the 2 groups. G-CSF given to donors before collection of cells did not prevent aplasia. These findings support the hypothesis that the pathogenesis of aplasia after DLI is not restricted to the destruction of recipient hematopoietic cells but also involves failure of donor hematopoiesis by undefined mechanisms.
Adolescent↗
Dog class I gene DLA-88 histocompatibility typing by PCR-SSCP and sequencing.
The dog has been an important model for solid organ and hematopoietic stem cell transplantation, as well as for studying autoimmune diseases, the growth of malignant tumors and the immunology of vaccines. Fundamental to the continuing usage of the canine model for research is the development of molecular-based histocompatibility typing. Previous histocompatibility methods have focused on class II genes. This study was undertaken to develop a molecular-based histocompatibility typing method for the most polymorphic class I gene, DLA-88. In this study, polymerase chain reaction single-stranded conformational polymorphism was used to separate alleles, thereby allowing sequenced-based typing.
Alleles↗
DLA-DQB1 alleles and bone marrow transplantation experiments in narcoleptic dogs.
Human narcolepsy is a neurological disorder known to be tightly associated with HLA-DQB1*0602. A clinically similar disorder has been described in various dog breeds. The canine form of the disease is inherited as an autosomal recessive disorder in Labrador retrievers and Doberman pinschers (canarc-1) but occurs sporadically in other breeds, most typically dachshunds and poodles. In this study, we have examined if there is a relationship between the development of narcolepsy and specific dog leukocyte antigen (DLA)-DQB1 alleles. Ninety-nine dogs were typed for DLA-DQB1-31 with narcolepsy and 68 control animals. Recent studies have linked the development of autosomal recessive canine narcolepsy to a disruption of the hypocretin receptor 2 (Hcrtr2) gene on the same chromosome as the canine MHC region (CFA12), but not close to the DLA. Four Hcrtr2-positive families (two Doberman pinscher families, one Labrador retriever family, one dachshund family) were analyzed at the DLA-DQ level. No relationship was found between narcolepsy and DLA in Hcrtr2-mediated narcolepsy but loose genetic linkage was observed (Zmax=2.3 at theta=25%, m= 40). Bone marrow transplantation between two DLA identical affected (Hcrtr2-/-) and unaffected (Hcrtr2+/-) siblings was also performed and found not to be successful neither in transmitting narcolepsy nor in relieving the symptoms in Doberman pinschers. DLA-DQB1 was next studied in 11 dogs with sporadic (non-familial) narcolepsy and in unrelated control animals of the same and different breeds. The allelic and carrier frequencies of various DLA-DQB1 alleles were analyzed. There was no strong positive or negative correlation between the development of narcolepsy and specific DLA-DQB1 alleles. These results do not support the involvement of DLA-DQ in canine narcolepsy, whether of sporadic or familial origin.
Animals↗
Three to six year follow-up of normal donors who received recombinant human granulocyte colony-stimulating factor.
One hundred and one donors who had received filgrastim (rhG-CSF) for the purpose of donating either granulocytes or peripheral blood stem cells (PBSC) for their relatives more than 3 years ago were contacted. All donors had received daily rhG-CSF at a median dose of 16 microg/kg/day (range 3-16) for a median of 6 days (range 3-15 days). All collection procedures were completed and short-term side-effects of rhG-CSF were mild in the majority of the donors. At a median time interval of 43.13 months (range 35-73), the donors were contacted to assess whether adverse effects related to rhG-CSF administration had occurred. Prior to rhG-CSF two donors had cancer, one had a myocardial infarction, one was hepatitis C virus positive, one had a history of sinusitis, one had Graves' disease and two had arterial hypertension. None worsened with the rhG-CSF administration but the donor with a history of infarction had an episode of angina following apheresis, and the donor with Graves' disease had a stroke 15 months after rhG-CSF. Two pregnancies occurred after the rhG-CSF administration and one donor was 2-3 weeks pregnant during rhG-CSF treatment. Three pregnancies resulted in two normal births and one in a spontaneous abortion of a pregnancy which occurred more than 2 years following rhG-CSF. In the time following rhG-CSF administration two donors developed cancer (breast and prostate cancer) at a follow-up of 70 and 11 months, respectively. One donor developed lymphadenopathy 38 months after the rhG-CSF, which spontaneously resolved. Blood counts were obtained in 70 donors at a median follow up of 40.4 months (range 16.8-70.8). Hematocrit was 43% (median, range 36.8-48), white blood cells were 5.7 x 109/l (median, range 3-14), granulocytes 3.71 x 109/l (median, range 1. 47-10.36), lymphocytes 1.67 x 109/l (median, range 0.90-3.96), monocytes 0.46 x 109/l (median, range 0.07-0.87) and platelet counts were 193.0 x 109/l (median, range 175.0-240.0). This study indicates that short-term administration of rhG-CSF to normal donors for the purpose of mobilizing the PBSC or granulocytes appears safe and without any obvious adverse effects more than 3 years after the donation. Bone Marrow Transplantation (2000) 25, 85-89.
Adolescent↗
Mini-allografts: ongoing trials in humans.
Conventional allogeneic stem cell transplantation is a valuable approach to therapy for many hematologic malignancies. However, high-dose conditioning regimens designed both to control the malignancy and to prevent graft rejection are associated with a high incidence of acute and long-term side-effects. This has largely precluded the use of allografting for patients older than 55 years or for younger patients with certain pre-existing organ damage. In order to manage the side-effects, transplants have traditionally been delivered in highly specialized hospital wards or intensive care settings. Thus, an important goal is to develop safer allografting procedures that can be extended to older patients or patients with pre-existing organ dysfunction who are currently excluded from consideration for transplant. Recent observations have shown that donor lymphocyte infusions (DLI) can eradicate some malignancies that relapse after conventional allografting. These observations confirmed earlier evidence in favor of a graft-versus-leukemia effect based on the association of graft-versus-host disease (GVHD) with a lower likelihood of relapse of malignancy after allografting. Given the potential efficacy of DLI as the sole modality for eradication of malignancy, new strategies for allografting can incorporate the concept of less intensive conditioning therapy which is given with the sole aim of facilitating allogeneic engraftment. Recent pre-clinical studies in a canine model have shown that conditioning regimens for allografting can be markedly reduced in intensity yet still achieve the goal of engraftment. This review briefly summarizes the initial translational clinical studies, using a minimally myelosuppressive-conditioning regimen based on low dose total body irradiation (TBI) or fludarabine alone or in combination with other drugs followed by a short course of immunosuppression with post-grafting cyclosporine and methotrexate or mycophenolate mofetil.
Animals↗
Unrelated donor marrow transplantation for acute myeloid leukemia: an update of the Seattle experience.
Between 1985 and 1998, 161 patients with primary acute myeloid leukemia (AML) received T-replete bone marrow transplantation (BMT) from unrelated donors in Seattle. Median age was 30 (range 1-55) years. Conditioning for BMT consisted of cyclophosphamide and total body irradiation in 154 (96%) cases and graft-versus-host disease prophylaxis was the standard methotrexate and cyclosporine combination in 134 (83%) cases. Median post-transplant follow-up was 2.9 years. Leukemia-free survival (LFS) at 5 years was 50+/-12% for transplants during first complete remission (n = 16), 28+/-8% during second CR (n = 40), 27+/-17% during subsequent CR (n = 8), 7+/-3% during relapse (n = 81) and 19+/-10% during primary induction failure (n = 16). The cumulative incidences of relapse were 19%, 23%, 25%, 44% and 63%, for the five groups, respectively. Transplantation during remission, a marrow cell dose above 3.5 x 10(8)/kg, and cytomegalovirus seronegative status before BMT in both patient and donor were favorable prognostic factors. Adults in any CR who received a marrow cell dose above 3.5 x 10(8)/mg had a LFS of 54+/-9% at 5 years. These data extend our previous findings on the association between a high marrow cell dose and improved survival and support the use of unrelated donor BMT for treatment of patients with high risk AML when a family match is not available.
Acute Disease↗
Clinical outcome after conversion to FK 506 (tacrolimus) therapy for acute graft-versus-host disease resistant to cyclosporine or for cyclosporine-associated toxicities.
This retrospective study describes the outcome in 53 patients who had immunosuppressive treatment changed from cyclosporine (CSP) to tacrolimus for resistant acute GVHD (n = 23), hemolytic uremic syndrome (HUS) (n = 13) or CSP-associated neurotoxicity (n = 17). Tacrolimus was administered at doses of 0.03 mg/kg/day intravenously or 0.12 mg/kg/day orally in divided doses, as tolerated. Median time of conversion to tacrolimus after transplant was day 47. Nineteen patients had treatment changed to tacrolimus for resistant acute GVHD grades III or IV, with the median day of conversion being day 49 after transplant. Two of 20 evaluable patients had a complete resolution of GVHD after changing treatment to tacrolimus, with 18 showing no improvement. Eleven evaluable patients had therapy changed to tacrolimus for CSP-associated neurotoxicity at a median of 36 days after transplant. Eight patients had resolution of neurotoxicity and three had partial improvement. Eleven evaluable patients had therapy changed to tacrolimus for HUS at a median of 46 days after transplant. One patient had complete resolution of HUS and 10 showed no response. Side-effects related to tacrolimus included renal toxicity (34%), neurotoxicity (15%) and HUS (9%). Nine (17%) patients remain alive, including six patients who had therapy changed to tacrolimus for CSP-associated neurotoxicity. While often successful for dealing with neurotoxicity, only a rare patient improved after therapy was changed from CSP to tacrolimus for HUS or resistant acute GVHD.
Acute Disease↗
Treatment of chronic myelomonocytic leukaemia by allogeneic marrow transplantation.
We evaluated the outcome of allogeneic bone marrow transplantation (BMT) in 21 patients with chronic myelomonocytic leukaemia (CMML) who were treated at the Fred Hutchinson Cancer Research Center between 1990 and 1998. There were 11 male and 10 female patients with a median age of 47.4 years (range 1.0-62.9). Patients were conditioned either with total body irradiation (TBI) and chemotherapy, with or without antithymocyte globulin (n = 19), or with chemotherapy alone (n = 2). The marrow donor was an HLA-identical sibling in 12 patients, an HLA-non-identical related donor in three patients and an unrelated volunteer donor in six patients. All evaluable patients achieved sustained engraftment. Fifteen patients developed grades II-IV acute graft-versus-host disease (GVHD). Nine patients (43.0%) are surviving disease free at 0.7-8.1 years (median 6.9) after transplantation. Five patients relapsed 75-660 d after transplant and all died. Five patients died with organ failure and two died with GVHD and associated infections. The Kaplan-Meier estimates of disease-free survival and relapse at 3 years were 39% and 25% respectively. The probability of survival was improved in patients with shorter disease duration compared with those with a long interval from diagnosis to BMT. Thus, as with other myeloproliferative diseases or myelodysplastic syndromes, BMT offers curative therapy for a proportion of patients with CMML. We suggest that patients with CMML who have a suitable donor should be considered for transplantation, probably early in their disease course. However, it will be important to develop new regimens with enhanced antileukaemic efficacy without further increasing regimen-related toxicity and mortality.
Adolescent↗
Mesenchymal stem cells as vehicles for gene delivery.
Mesenchymal stem cells contribute to the regeneration of mesenchymal tissues such as bone, cartilage, muscle, ligament, tendon, adipose, and marrow stroma. Transduction of mesenchymal stem cells from species other than humans is required for the development of disease models in which mesenchymal stem cells-based gene delivery is evaluated. Attempts to transduce mesenchymal stem cells from some species with amphotropic retroviral vectors were unsuccessful, leading to comparative mesenchymal stem cells transductions with xenotropic and gibbon-ape leukemia virus envelope-pseudotyped retroviral vectors. Human, baboon, canine, and rat mesenchymal stem cells were transduced optimally with amphotropic vector supernatants. In contrast, sheep, goat, and pig mesenchymal stem cells showed highest transduction levels with xenotropic retroviral vector supernatant, and rabbit mesenchymal stem cells were transduced optimally with gibbon-ape-enveloped vectors. Using a myeloablative canine transplantation model and gene-marked canine mesenchymal stem cells, the biodistribution of infused and ex vivo expanded mesenchymal stem cells were examined. The majority of transduced canine mesenchymal stem cells were found in the bone marrow samples. The current study shows the use of mesenchymal stem cells as a delivery vehicle for gene transfer studies, and validates the feasibility of delivering mesenchymal stem cells to the marrow compartment for stromal regeneration after cancer-associated cytotoxic therapies.
Animals↗
The future of allogeneic hematopoietic stem cell transplantation: minimizing pain, maximizing gain.
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Animals↗
Nonmyeloablative transplants: preclinical and clinical results.
Conditioning regimens have been intensified to a level at which organ toxicties are dose-limiting, which restricts the application of hematopoietic stem cell transplants to relatively young patients in otherwise good clinical condition. Studies done in a canine model have demonstrated that stable allogeneic mixed donor/host hematopoietic chimerism can be established by the administration of a sublethal dose of 2.0 Gy total body irradiation followed by immunosuppression with mycophenolate mofetil and cyclosporine after major histocompatibility complex-identical marrow transplantation. Both host-versus-graft and graft-versus-host reactions are controlled with mycophenolate mofetil and cyclosporine, which results in a stable state of graft/host tolerance manifested by stable mixed donor/ host hematopoietic chimerism. Current efforts are directed at replacing pretransplant radiation by anti-T-cell reagents, such as antibodies to T cells, or by purine antagonists, such as pentostatin (Nipent; SuperGen, San Ramon, CA). Given the minimal toxicity of this approach in dogs, a clinical study was initiated that uses an almost identical conditioning regimen. Thus far, 26 patients have been treated. Results to date indicate that this is a well-tolerated procedure that can be performed entirely in an outpatient setting. All patients have shown primary engraftment with persistence of mixed or full donor chimerism present through at least 2 months after transplant. Three patients experienced nonfatal graft rejection between 2 and 3 months after transplant, with a return to baseline peripheral counts over the subsequent 1 to 2 months. Acute graft-versus-host disease developed in 10 of 24 evaluable patients, occurring only after discontinuation of mycophenolate mofetil, and was controlled with additional immunosuppression in all cases. Overall, this novel nonmyeloablative conditioning regimen has been well tolerated and has encouraged us to investigate these transplants in other clinical settings, including using HLA-matched unrelated donors.
Animals↗
Long-term follow-up of a randomized study comparing cyclophosphamide and total body irradiation with busulfan and cyclophosphamide for patients receiving allogenic marrow transplants during chronic phase of chronic myeloid leukemia.
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Antineoplastic Combined Chemotherapy Protocols↗
Recognition of major histocompatibility complex class II antigens by two anti-HLA-DR monoclonal antibodies on canine marrow cells correlates with effects on in vitro and in vivo hematopoiesis.
BACKGROUND: The role of major histocompatibility complex class II antigens in hematopoiesis is not well defined. We have shown that in vitro depletion of HLA-DR+ cells from canine marrow (e.g., by anti-HLA-DR monoclonal antibody [mAb] H81.9 and complement) prevents hematopoietic recovery. In vivo administration of the same mAb H81.9 after transplantation of unmanipulated autologous marrow results in graft failure. In vitro mAb H81.9 inhibited colony formation from short-term and long-term marrow cultures. METHODS AND RESULTS: We investigated the effect of another mAb, Ca1.41, which also recognizes nonpolymorphic determinants on human (HLA-DR) and canine major histocompatibility complex class II antigens but is reactive with a narrower spectrum of cells in both canine peripheral blood and marrow than mAb H81.9 (and other anti-HLA-DR mAbs). In contrast to all other anti-HLA-DR mAbs tested, Ca1.41 did not interfere with colony formation in short-term or long-term marrow cultures and spared a population of small mononuclear cells with low forward light scatter that was eliminated via apoptosis by exposure to mAb H81.9. These target cells included lymphocytes and CD34+ hemopoietic precursors that expressed MHC class II molecules as determined by mAb H81.9 but not by mAb Ca1.41. In addition, transmembrane signaling and up-regulation of interleukin-1beta mRNA occurred with mAb H81.9 but not with Ca1.41. Transplantation of autologous marrow treated in vitro cytolytically with mAb Ca1.41 allowed for complete hematopoietic reconstitution. Further, in vivo administration of Ca1.41 posttransplant did not lead to autologous graft failure as had been observed with mAb H81.9. CONCLUSIONS: These results support the notion that major histocompatibility complex class II is expressed on early hematopoietic precursor cells but recognition is dependent upon the mAb used. Preliminary studies show that mAb H81.9 triggered transmembrane signaling, resulting in up-regulation of interleukin-1beta and apoptosis, although mAb Ca1.41 did not. The fact that Ca1.41 binding was modified in the presence of exogenous invariant chain-derived peptide suggests that both binding and signaling are peptide dependent.
Animals↗
A phase I-II clinical trial to evaluate removal of CD4 cells and partial depletion of CD8 cells from donor marrow for HLA-mismatched unrelated recipients.
We conducted a phase I-II clinical trial to test the hypothesis that removal of CD4 cells from an HLA-mismatched unrelated marrow graft would substantially reduce the risk of grades III-IV graft-versus-host disease (GVHD) and that retention of a specified number of CD8 cells in the graft would be sufficient to prevent rejection. Patients were eligible for this study when an HLA-A, -B, or -DRB1-matched unrelated donor could not be identified. HLA matching of the donor and recipient was based on typing of HLA-A and -B antigens by serologic methods and by typing of HLA-DRB1 alleles by molecular methods, and donors were selected when disparity was limited to a single HLA-DRB1 allele or a single HLA-A or -B antigen. Twenty-seven patients with hematologic malignancy or aplastic anemia were prepared to receive a transplant with conventional regimens of cyclophosphamide and fractionated total body irradiation, and a standard regimen of methotrexate and cyclosporine was given for GVHD prophylaxis. CD4 cells were removed from the donor marrow, and the numbers of CD8 cells were adjusted systematically in graded steps for successive patients, depending on the occurrence of grades III-IV GVHD or graft failure in previously enrolled patients. Removal of CD4 cells did not cause graft rejection or appreciably decrease the risk of grades III-IV GVHD. Depletion of CD8 cells was associated with an increased risk of rejection with either HLA-DRB1 disparity or with HLA-A or -B disparity. With either type of disparity, the risk of grades III-IV GVHD is likely to be higher than 15% at any dose of CD8 cells associated with less than 5% risk of graft failure. The absence of graft failure associated with CD4 depletion supports the hypothesis that donor CD4 cells are not essential for preventing marrow graft rejection in humans. The correlation between graft failure and the number of CD8 cells in the donor marrow supports the hypothesis that donor CD8 cells help to prevent marrow graft rejection.
Adolescent↗
The use of granulocyte colony-stimulating factor during retroviral transduction on fibronectin fragment CH-296 enhances gene transfer into hematopoietic repopulating cells in dogs.
A competitive repopulation assay in the dog was used to develop improved gene transfer protocols for hematopoietic stem cell gene therapy. Using this assay, we previously showed improved gene transfer into canine hematopoietic repopulating cells when CD34-enriched marrow cells were cocultivated on gibbon ape leukemia virus (GALV)-based retrovirus vector-producing cells. In the present study, we have investigated the use of fibronectin fragment CH-296 and 2 growth factor combinations to further improve gene transfer efficiency. CD34-enriched marrow cells from each dog were prestimulated for 24 hours and then divided into 3 equal fractions. Two fractions were placed into flasks coated with either CH-296 or bovine serum albumin (BSA) and virus-containing medium supplemented with growth factors, and protamine sulfate was replaced 4 times over a 48-hour period. One fraction was cocultivated on irradiated PG13 (GALV-pseudotype) packaging cells for 48 hours. In 2 animals, cells of the different fractions were transduced in the presence of human FLT-3 ligand (FLT3L), canine stem cell factor (cSCF), and human megakaryocyte growth and development factor (MGDF), and in 2 other dogs, transduction was performed in the presence of FLT3L, cSCF, and canine granulocyte-colony stimulating factor (cG-CSF). The vectors used contained small sequence differences, allowing differentiation of cells genetically marked by the different vectors. After transduction, nonadherent and adherent cells from all 3 fractions were pooled and infused into lethally irradiated dogs. Polymerase chain reaction and Southern blot analysis were used to determine the persistence of the transferred vectors in the peripheral blood and marrow cells after transplantation. The highest levels of gene transfer were obtained when cells were transduced in the presence of FLT3L, cSCF, and cG-CSF (gene transfer levels of more than 10% for more than 8 months so far). Compared with the 2 animals that received cells transduced with FLT3L, cSCF, and MGDF, gene transfer levels were significantly higher when dogs received cells that were transduced in the presence of cG-CSF. Transduction on CH-296 resulted in gene transfer levels that were at least as high as transduction by cocultivation. In summary, the overall levels of gene transfer obtained with these conditions should be sufficiently high to allow stem cell gene therapy studies aimed at correcting genetic diseases in dogs as a model for human gene therapy.
Animals↗