Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The efficacy of graft-vs.-leukemia induction to treat relapses after allogeneic progenitor cell transplant in a variety of hematologic malignancies suggest that it may be possible to use the graft versus leukemia as primary therapy for these malignancies without the need of myeloablative therapy. This type of strategy should be explored initially in patients considered ineligible for conventional myeloablative therapies either because of age or concurrent medical conditions. GVHD remains a major obstacle that needs to be overcome. Although a potentially lower level of inflammatory cytokines may be present after non-myeloablative therapies, fatal GVHD still occurs. Methods to diminish GVHD after allogeneic transplant include selective T-cell depletion (39-43) and transduction of donor T-cells with Herpes simplex virus thymidine kinase which renders these cells sensitive to ganciclovir treatment (see chapter 16). We and others have demonstrated that nonablative chemotherapy using fludarabine combinations is sufficiently immunosuppressive to allow engraftment of allogeneic blood progenitor cells. Patients could then receive graded doses of donor lymphocytes without rejection, to mediate GVL. Ideally, this therapy could be titrated to levels of residual malignant cells using sensitive detection techniques. This novel approach to therapy would reduce the toxicity of the transplant procedure, allow it to be administered more safely to debilitated patients and possibly extend the use of transplantation to older patients who are not presently eligible for BMT procedures. Other possible indications include treatment of non-malignant disorders and induction of tolerance for solid organ transplantation.
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PMID:Non myeloablative "mini transplants". 1080 Jun 46

We have initiated a phase I/II clinical trial, involving the use of herpes simplex thymidine kinase gene (HS-tk)-expressing donor primary T cells, in order to modulate the graft-versus-host disease (GvHD) occurring after allogeneic hematopoietic stem cell transplantation. The preparation of gene-modified T cells (TkTCs) required a 12-day ex vivo culture comprising an initial OKT3 and IL-2 stimulation, a retrovirus-mediated transduction, and a 7-day selection step in the presence of G418 and IL-2. The low transduction efficiency as well as the culture conditions may significantly alter the diversity of the T cell repertoire. We therefore examined the T cell repertoire of HS-tk-expressing T cell samples from 11 different donors by the Immunoscope method. This method analyzes the hypervariable region of the T cell receptor beta chain (TCRBV) by amplifying the complementarity-determining region 3 (CDR3) and determining size diversity. In all examined samples (four of which were infused into patients), all TCRBV subfamilies were represented with, however, a significant skewing within a minority of subfamilies. Kinetic studies demonstrated that this skewing appeared between day 7 and day 12, with dates of appearance variable from one subfamily to another. In addition, the repertoire analysis of two different culture products, harvested and produced at different times from the same donors, suggested that some repertoire abnormalities could be donor specific. Quantitative analysis revealed no major modifications in gene usage, even in skewed TCRBV subfamilies, with a few clonal expansions concerning a limited number of TCRBV subfamilies. Importantly, identical abnormalities were found in control cells grown in parallel under similar conditions but not transduced or selected, thus demonstrating that these abnormalities were not related to the transduction or the selection process, but rather to the ex vivo culture. The initial stimulus used for T cell activation is a major source of TCRBV perturbation, since replacing the OKT3 + IL-2 stimulus by CD3 + CD28 monoclonal antibody-coated beads prevented the occurrence of alterations. Overall, the HS-tk-expressing T cells used in our clinical trial exhibit limited TCR repertoire skewing that is not due to the transduction/selection procedure. However, future T cell gene transfer protocols for clinical trials should be designed to take into account or possibly prevent such T cell repertoire alterations.
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PMID:Retrovirus-mediated gene transfer in primary T lymphocytes: influence of the transduction/selection process and of ex vivo expansion on the T cell receptor beta chain hypervariable region repertoire. 1083 17

Herpes simplex virus (HSV) infections in 75 allogeneic stem cell transplant recipients were analyzed. Sixteen patients developed HSV disease following transplantation. The risk factors were age, sex (females), unrelated donor graft, and graft-versus-host disease (GVHD) grade >/=2. Seven patients did not respond to acyclovir, and 3 patients failed to respond to foscarnet. Isolates from 4 patients developed resistance to acyclovir/penciclovir, and 3 patients had foscarnet-resistant isolates. The remaining 3 patients failed to respond to acyclovir, despite having sensitive isolates. All the isolates were sensitive to cidofovir, for which the IC(50) values correlated inversely with those for acyclovir (P=.01). The risk factors for clinical resistance to antiviral drugs were a GVHD grade >/=2 (P=.001) and the lack of ganciclovir prophylaxis (P=.01), with a higher nonrelapse mortality in the latter group (P<.0001). Clinical as well as in vitro resistance to antiviral drugs is common in patients with severe GVHD and is associated with a poor outcome.
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PMID:Resistance to antiviral drugs in herpes simplex virus infections among allogeneic stem cell transplant recipients: risk factors and prognostic significance. 1083 92

Generation of an efficient graft-versus-leukemia (GVL) effect in patients with hematological malignancies who relapse after allogeneic bone marrow transplantation depends in part upon the number of infused T lymphocytes. Currently, a GVL reaction cannot be achieved without inducing concomitant graft-versus-host disease (GVHD); thus, one strategy is to try to modulate this GVL/GVHD ratio. We engineered human T lymphocytes with herpes simplex virus-thymidine kinase and neomycin resistance genes, with an LXSN-derived vector that confers a ganciclovir-specific sensitivity to the transduced T cells. We analyzed proliferation, interleukin-2 production, alloreactivity in a mixed lymphocyte culture, and clonogenicity during the different stages of retroviral infection and G418 selection. Our results confirm that a sufficient number of transduced T lymphocytes can be obtained after selection for clinical studies. Their proliferative activity, alloresponsiveness, and ability to produce and respond to interleukin-2 were retained. Compared with control populations, their clonogenicity, as assessed by limiting dilution assays, was reduced after retroviral infection and G418 selection by 1.6 and 2.9 logs, respectively, with both viral supernatant incubation and coculture procedures. This study shows that infection and selection with the thymidine kinase-neomycin resistance gene retroviral vector significantly reduces the number of functional T lymphocytes. This finding should be taken into account when establishing the dose of T lymphocytes necessary to trigger a modulated GVL/GVHD effect.
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PMID:T-lymphocyte function after retroviral-mediated thymidine kinase gene transfer and G418 selection. 1088 24

Infusions of donor peripheral blood T cells can induce durable remissions of Epstein-Barr virus (EBV) lymphomas complicating marrow grafts, but they contain alloreactive T cells capable of inducing graft-versus-host disease. EBV-specific T-cell lines or clones avoid this problem but require 30 to 40 days of culture to establish. To accelerate the generation of EBV-specific T cells, we tested whether retroviral vectors, which only integrate in dividing cells, could be used to transduce and select antigen-reactive T cells early after sensitization to autologous EBV-transformed B cells. T cells were transduced with a dicistronic retroviral vector, NIT, which encodes low-affinity nerve growth factor receptor as an immunoselectable marker and herpes simplex virus thymidine kinase as a suicide gene, at different time points after sensitization. EBV-specific cytotoxic T lymphocyte precursor (CTLp) frequencies in purified NIT(+) T-cell fractions transduced on day 8 of culture were comparable to those of EBV-specific T-cell lines cultured for 30 days or more. Alloreactive CTLp frequencies were markedly reduced in the NIT(+) fraction relative to the untransduced T-cell population. NIT(+) fractions transduced on day 8 possessed more CD4(+) T cells than the cell lines at day 30 and exhibited the same selective pattern of reactivity against immunodominant antigens presented by specific HLA alleles. In contrast, T cells transduced with NIT 5 days after stimulation with mitogen and interleukin-2 were relatively depleted of T cells specific for autologous EBV-transformed cells. Thus, retroviral vectors may be used for rapid selection of viral antigen-reactive T cells depleted of alloreactive T cells.
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PMID:Rapid selection of antigen-specific T lymphocytes by retroviral transduction. 1089 38

Expression of suicide genes (e.g. herpes simplex virus thymidine kinase,HSV-TK) in T cells is an appealing approach to regulate graft-versus-host disease in adoptive immunotherapy. Here we report the optimization of retroviral infection of canine T cells. Canine T cells were stimulated either with phytohemagglutinin (PHA, 2 microg/ml) for 24-72 hours or with 100 U/ml interleukin-2 for seven days. Stimulated cells were co-cultivated with irradiated virus-producing cells. Transduction efficiencies ranged from 4% to 45% using PG13, a gibbon ape leukemia virus envelope (env) pseudotyped packaging cell line. Infection of cells with GPenvAM12, expressing the amphotropic Moloney murine leukemia virus env, did not yield a satisfactory percentage of transduced cells. Enrichment of transduced cells was performed using immunoselection, and gave a purity of up to 98%. Transfusion of 1 x 10(6) transduced cells per kilogram body weight showed that transduced cells could convert mixed chimerism to 100% and transfer immunity to a specific antigen. Transduced cells were repeatedly detected in peripheral blood and bone marrow by polymerase chain reaction with primers specific for the HSV-TK gene. We have demonstrated the feasibility of using the canine model to study gene therapy as a preclinical model.
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PMID:Expression of HSV-TK suicide gene in primary T lymphocytes: the dog as a preclinical model. 1097 36

Administration of donor T cells expressing the herpes simplex-thymidine kinase (HS-tk) with a hematopoietic stem cell (HSC) transplantation could allow, if graft-versus-host disease (GVHD) was to occur, a selective in vivo depletion of these T cells by the use of ganciclovir (GCV). The study evaluates the feasibility of such an approach. Escalating numbers of donor HS-tk-expressing CD3(+) gene-modified cells (GMCs) are infused with a T-cell-depleted bone marrow transplantation (BMT). Twelve patients with hematological malignancies received 2 x 10(5) (n = 5), 6 x 10(5) (n = 5), or 20 x 10(5) (n = 2) donor CD3(+) GMCs/kg with a BMT from a human leukocyte antigen (HLA)-identical sibling. No acute toxicity was associated with GMC administration. An early increase of circulating GMCs followed by a progressive decrease and long-lasting circulation of GMCs was documented. GCV treatment resulted in significant rapid decrease in circulating GMCs. Three patients developed acute GVHD, with a grade of at least II, while one patient developed chronic GVHD. Treatment with GCV alone was associated with a complete remission (CR) in 2 patients with acute GVHD, while the addition of glucocorticoids was necessary to achieve a CR in the last case. Long-lasting CR occurred with GCV treatment in the patient with chronic GVHD. Unfortunately, Epstein-Barr virus-lymphoproliferative disease occurred in 3 patients. Overall, the administration of low numbers of HS-tk-expressing T cells early following an HLA-identical BMT is associated with no acute toxicity, persistent circulation of the GMCs, and GCV-sensitive GVHD. Such findings open the way to the infusion of higher numbers of gene-modified donor T cells to enhance post-BMT immune competence while preserving GCV-sensitive alloreactivity.
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PMID:Administration of herpes simplex-thymidine kinase-expressing donor T cells with a T-cell-depleted allogeneic marrow graft. 1113 43

The herpes simplex virus thymidine kinase gene type 1 (HSV-Tk) ganciclovir (GCV) system is a novel therapeutic strategy for the modulation of graft-versus-host disease (GVHD), a major complication of allogeneic stem cell transplantation (allo-SCT). Retroviral-mediated gene transfer of the HSV-Tk gene into donor T lymphocytes before allo-SCT may allow their in vivo selective depletion after treatment with GCV. The expression of the HSV-Tk gene was analyzed in vitro in CEM cells, a human lymphoblastoid cell line, transduced with 2 different vectors, each containing the HSV-Tk gene and a selectable marker gene. GCV-resistant clones were identified within the clones expressing the marker gene. Characterization of the molecular events leading to this resistance revealed a 227-bp deletion in the HSV-Tk gene due to the presence of cryptic splice donor and acceptor sites within the HSV-Tk gene sequence. Furthermore, it was confirmed that this deletion was present in human primary T cells transduced with either vector and in 12 patients who received transduced donor T cells, together with a T-cell-depleted allo-SCT. In vivo circulating transduced T cells containing the truncated HSV-Tk gene were identified in all patients immediately after infusion and up to 800 days after transplantation. In patients who received GCV as treatment for GVHD, a progressive increase in the proportion of transduced donor T cells carrying the deleted HSV-Tk gene was observed. These results suggest that the limitations within the HSV-Tk/GCV system can be improved by developing optimized retroviral vectors to ensure maximal killing of HSV-Tk-transduced cells.
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PMID:Molecular mechanism for ganciclovir resistance in human T lymphocytes transduced with retroviral vectors carrying the herpes simplex virus thymidine kinase gene. 1113 51

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow transplantation. One strategy to treat GVHD is to equip donor T cells with a conditional suicide mechanism that can be triggered when GVHD occurs. The herpes simplex virus thymidine kinase (HSV-tk)/ganciclovir system used clinically has several limitations, including immunogenicity and cell cycle dependence. An alternative switch based on chemically inducible apoptosis was designed and evaluated. A chimeric human protein was expressed comprising an extracellular marker (DeltaLNGFR), the Fas intracellular domain, and 2 copies of an FK506-binding protein (FKBP). Primary human T lymphocytes retrovirally transduced with this construct could be purified to homogeneity using immunomagnetic beads. Genetic integrity of the construct was ensured by redesigning repetitive sequences. Transduced T cells behaved indistinguishably from untransduced cells, retaining the ability to mount a specific antiallogeneic immune response. However, they rapidly underwent apoptosis with the addition of subnanomolar concentrations of AP1903, a bivalent "dimerizer" drug that binds FKBP and induces Fas cross-linking. A single 2-hour treatment eliminated approximately 80% of T cells, and multiple exposures induced further apoptosis. T cells were eliminated regardless of their proliferation state, suggesting that the AP1903/Fas system, which contains only human components, is a promising alternative to HSV-tk for treating GVHD.
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PMID:A Fas-based suicide switch in human T cells for the treatment of graft-versus-host disease. 1122 67

Conditional ablation of alloreactive donor T-cells to prevent or treat graft-versus-host disease (GvHD) in the context of allogeneic haematopoietic stem cell transplantation could significantly contribute to expand the use of alloreactivity as a treatment modality. The prevention and treatment of GvHD induced by herpes simplex virus 1-thymidine kinase (HS-tk)-expressing donor T-cells by ganciclovir (GCV) has been demonstrated. Early clinical findings suggest that the use of such cells early or late after transplantation is associated with no acute toxicity, persistent circulation of the gene-modified cells (GMC) and GCV-sensitive GvHD. However, a number of limitations such as reduced immune function of gene-modified T-cells, immunogenicity of GMC as well as presence of a truncated HS-tk gene have emerged and need to be addressed.
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PMID:Use of suicide gene-expressing donor T-cells to control alloreactivity after haematopoietic stem cell transplantation. 1129 57


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