Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UMLS:C0018133 (graft-versus-host disease)
18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has not been possible to determine the singular contribution of naive T lymphocytes to antigen-specific immunity after hematopoietic stem cell transplantation (HSCT), because of the confounding effects of donor-derived antigen-specific T lymphocytes present in most hematopoietic stem cell (HSC) products. Because umbilical cord blood contains only naive T lymphocytes, we longitudinally evaluated the recipients of unrelated cord blood transplantation (UCBT) for the presence of T lymphocytes with specificity for herpesviruses, to determine the contribution of the naive T lymphocytes to antigen-specific immune reconstitution after HSCT. Antigen-specific T lymphocytes were detected early after UCBT (herpes simplex virus on day 29; cytomegalovirus on day 44; varicella zoster virus on day 94). Overall, 66 of 153 UCBT recipients developed antigen-specific T lymphocytes to 1 or more herpesviruses during the evaluation period. The likelihood of developing antigen-specific T lymphocyte function was not associated with immunophenotypic T lymphocyte reconstitution, transplant cell dose, primary disease, or acute and chronic graft-versus-host disease. These results indicate that naive T lymphocytes present in the HSC inoculum can contribute to the generation of antigen-specific T-lymphocyte immunity early after transplantation.
...
PMID:Antigen-specific T-lymphocyte function after cord blood transplantation. 1716 16

Retroviral transfer of the Herpes Simplex thymidine kinase (HSVTK) suicide gene to donor T cells has been used as a safety strategy against graft-versus-host disease following allogeneic stem cell transplantation. The feasibility of this strategy in human studies has been demonstrated, but a number of limitations have become apparent. Preactivation of donor lymphocytes using mitogens or monoclonal antibodies is essential for retroviral transduction, but can compromise subsequent T-cell function in vivo. We report the application of lentiviral vectors for transduction of T cells in cytokine culture, without activation through the T-cell receptor. Using vectors encoding either enhanced green fluorescent protein or a truncated CD34/mutant HSVTK fusion selection/suicide construct, we investigated the properties of T cells after gene modification. We found that following cytokine stimulation, a fraction of T cells undergoes division, and transgene expression occurred predominantly in these cells. Antiviral and alloreactive responses were preserved in these populations, and in contrast to fully activated T cells, there was minimal perturbation of regulatory T-cell numbers. We conclude that the use of interleukin-7 for lentiviral transduction offers the greatest potential for gene transfer to T cells without loss of function, and is favored for the clinical production of suicide gene modified T cells.
...
PMID:Lentiviral vectors for T-cell suicide gene therapy: preservation of T-cell effector function after cytokine-mediated transduction. 1723 14

The extensive exploitation of the antitumor effect of donor lymphocytes infused after allogeneic hematopoietic stem-cell transplantation (allo-HSCT) is limited by the risk of graft-versus-host disease (GvHD). To overcome this limitation, we investigated the therapeutic potential of donor lymphocytes engineered with the suicide gene thymidine kinase of herpes simplex virus (TK) in 23 patients experiencing recurrence of hematologic malignancies after allo-HSCT. Long-term follow-up of infused patients included analysis of engraftment of genetically engineered lymphocytes, in vivo assessment of antitumor effect, and control of GvHD by ganciclovir. All 17 patients evaluable for engraftment and graft-versus-leukemia (GvL) had circulating TK(+) cells detectable beginning at a median time of 18 days. Eleven patients (65%) experienced a substantial clinical benefit resulting in 6 (35%) complete remissions and 5 (29%) partial responses. The antitumor effect tightly correlated with the in vivo expansion of TK(+) cells. Seven patients received ganciclovir, resulting in elimination of TK(+) cells and effective and selective treatment of GvHD. Immunization against HSV-TK was observed in 7 patients but did not preclude an effective GvL. These data validate the feasibility, safety, and efficacy of TK(+) cells in the context of allografting and represent the basis for a broader application of this technology.
...
PMID:Antitumor effects of HSV-TK-engineered donor lymphocytes after allogeneic stem-cell transplantation. 1732 16

In our previous phase 1/2 study aimed at controlling graft-versus-host disease, 12 patients received Herpes simplex virus thymidine kinase (HSV-tk(+))/neomycin phosphotransferase (NeoR(+))-expressing donor gene-modified T cells (GMCs) and underwent an HLA-identical sibling T-cell-depleted bone marrow transplantation (BMT). This study's objective was to follow up, to quantify, and to characterize persistently circulating GMCs more than 10 years after BMT. Circulating GMCs remain detectable in all 4 evaluable patients. However, NeoR- and HSV-tk-polymerase chain reaction (PCR) differently quantified in vivo counts, suggesting deletions within the HSV-tk gene. Further experiments, including a novel "transgene walking" PCR method, confirmed the presence of deletions. The deletions were unique, patient-specific, present in most circulating GMCs expressing NeoR, and shown to occur at time of GMC production. Unique patient-specific retroviral insertion sites (ISs) were found in all GMCs capable of in vitro expansion/cloning as well. These findings suggest a rare initial gene deletion event and an in vivo survival advantage of rare GMC clones resulting from an anti-HSV-tk immune response and/or ganciclovir treatment. In conclusion, we show that donor mature T cells infused with a T-cell-depleted graft persist in vivo for more than a decade. These cells, containing transgene deletions and subjected to significant in vivo selection, represent a small fraction of T cells infused at transplantation.
...
PMID:Deletions within the HSV-tk transgene in long-lasting circulating gene-modified T cells infused with a hematopoietic graft. 1771 34

Several clinical studies of gene-modified T cells have shown limited in vivo function of the cells, immunogenicity of the transgene, and lack of a selective advantage for gene-modified T cells. To address these problems, we developed a lentiviral vector (LV) that provides a selectable, proliferative advantage and potentially decreases immunogenicity for transduced T cells. The bicistronic vector expressed two genes linked with an internal ribosomal entry site. One gene is a variant of the inosine monophosphate dehydrogenase 2, inosine monophosphate dehydrogenase (IMPDH(IY)), conferring resistance to the immunosuppressive drug mycophenolate mofetil (MMF). The other is a suicide gene, herpes simplex virus thymidine kinase (HSV-TK), rendering proliferating cells sensitive to ablation with ganciclovir, fused to the selectable transmembrane marker DeltaCD34 (DeltaCD34/TK). Cells transduced with LV-DeltaCD34/TK.IMPDH(IY) were efficiently enriched by immunomagnetic selection for CD34, proliferated in 0.5-5 microM MMF, and were killed by 0.5-25 microg ml(-1) ganciclovir. We demonstrate efficient selection and killing of gene-modified cells and suggest LV-DeltaCD34/TK.IMPDH(IY)-transduced T cells could be used to facilitate allogeneic hematopoietic cell engraftment. The expression of IMPDH(IY) would allow in vivo selection with MMF, and DeltaCD34/TK expression would allow rapid and safe elimination of transduced T cells if graft-versus-host disease developed.
...
PMID:Lentiviral vector conferring resistance to mycophenolate mofetil and sensitivity to ganciclovir for in vivo T-cell selection. 1780 3

After haploidentical stem cell transplantation immune recovery is inevitably slow and infectious related mortality is about 30-40%. Immune reconstitution could be improved by infusing donor T cells, but the obstacle is graft-versus-host disease. In a mixed lymphocyte reaction, alloantigen-stimulated T cells uptake 4,5-dibromorhodamine methyl ester (TH9402), a compound that is structurally similar to rhodamine. TH9402 preferentially localizes in mitochondria and when exposed to 500- to 600-nm wavelength visible light delivered through the Theralux device (Kiadis Pharma, Amsterdam, The Netherlands), it becomes highly cytotoxic through oxidative damage. This study investigated a range of parameters, and combinations thereof, with the aim of achieving optimal T cell allodepletion and preservation of pathogen-specific responses. We report on 11 clinical scale dry runs which reproducibly yielded the following results. Blood mononuclear cells were stimulated with haploidentical irradiated (20 Gy). Blood mononuclear cells in a mixed lymphocyte reaction. Cells were then incubated with TH9402 and exposed to light delivered through the Theralux device. Optimal conditions for T cell allodepletion emerged as (1) duration of mixed lymphocyte reaction: 24 h; (2) responder cell concentration: 3-5x10(6)/ml; (3) TH9402 concentration: 5 microM; (4) quantity of internalized TH9402, as measured by mean fluorescence intensity (MFI): 20,000-25,000 MFI; (5) energy delivered: 0.1 J/cm(2). Only under these conditions were the frequencies (by limiting dilution analyses) of alloantigen-specific T cells maximally reduced, i.e., 2467+/-639 (mean+/-SD) times, when compared with non-TH9402-treated cells. Pathogen-specific responses to pathogen antigens such as Cytomegalovirus, Adenovirus, Varicella Zoster Virus, Herpes Simplex Virus, Aspergillus fumigatus, Candida albicans, Toxoplasma gondii were retained, although with a 19+/-9.7 times reduction in frequency. This remarkable drop in frequency of alloreactive T cells is expected to allow safe infusion of relatively large numbers of T cells across histocompatibility barriers for adoptive transfer of donor immunity. Consequently, a clinical trial is planned to incorporate infusion of photo-allodepleted donor T cells after haploidentical stem cell transplantation with the aim of decreasing infection-related mortality.
...
PMID:Photodynamic purging of alloreactive T cells for adoptive immunotherapy after haploidentical stem cell transplantation. 1797 31

Administration of herpes simplex thymidine kinase (HSV-tk)-expressing, gene-modified T cells (GMCs) with T cell-depleted bone marrow transplantation (TCD-BMT) can allow modulation of posttransplantation alloreactivity. Twelve patients received 2 x 10(5) to 2 x 10(6) CD3+ donor GMCs per kilogram with HLA-identical sibling TCD-BMT. Despite extensive T cell depletion of bone marrow, an intensive conditioning regimen, and immunosuppressive graft-versus-host disease (GvHD) prophylaxis, infusion at the time of TCD-BMT of this low number of GMCs sufficed to induce a rapid GMC-specific immune response, as detected by interferon- enzyme- linked immunospot assay in six of eight patients, preferentially targeting HSV-tk. Maximal responses were reached early (median time, 49 [35-68] days post-BMT), with a subsequent rapid and significant decrease in five of six evaluable patients. Immune responses were negatively correlated with the maximal circulating GMC counts. However, such immune response did not result in the elimination of circulating GMCs and was not associated with measurable ex vivo cytotoxic activity against GMCs. Furthermore, alloreactive GMCs still could induce GCV-sensitive GvHD in one patient despite an ongoing immune response. Overall, infusion of HSV-tk-expressing GMCs at the time of BMT results in an early immune response. Such immune response may be altered and may not prevent persistent GCV-sensitive alloreactivity.
...
PMID:Early immune response against retrovirally transduced herpes simplex virus thymidine kinase-expressing gene-modified T cells coinfused with a T cell-depleted marrow graft: an altered immune response? 1881 Jul 97

Conditional elimination of infused gene-modified alloreactive T cells, using suicide gene activation, has been shown to be an efficient strategy to abrogate severe graft-versus-host disease (GvHD) in the context of adoptive immunotherapy. To overcome shortcomings of the most widely used suicide gene, wild-type (splice-corrected) herpes simplex virus thymidine kinase (scHSVtk), we generated two new variants: the codon-optimized coHSVtk and, by introducing an additional mutation (A168H), the novel TK.007. We transduced human hematopoietic cell lines and primary T cells with retroviral "sort-suicide vectors" encoding combinations of selection markers (tCD34 and OuaSelect) with one of three HSVtk variants. In vitro we observed higher expression levels and sustained long-term expression of TK.007, indicating lower nonspecific toxicity. Also, we noted significantly improved kinetics of ganciclovir (GCV)-mediated killing for TK.007-transduced cells. In an experimental (murine) allogeneic transplantation model, TK.007-transduced T cells mediated severe GvHD, which was readily abrogated by application of GCV (10 mg/kg). Last, we established a modified allotransplantation model that allowed quantitative comparison of the in vivo activities of TK.007 versus scHSVtk. We found that TK.007 mediates both significantly faster and higher absolute killing at low GCV concentrations (10 and 25 mg/kg). In summary, we demonstrate that the novel TK.007 suicide gene combines better killing performance with reduced nonspecific toxicity (as compared with the frequently used splice-corrected wild-type scHSVtk gene), thus representing a promising alternative for suicide gene therapy.
...
PMID:TK.007: A novel, codon-optimized HSVtk(A168H) mutant for suicide gene therapy. 2020 26

Paraproteinaemia following allo-SCT is common. We analysed 91 consecutive patients undergoing allo-SCT; conditioning included alemtuzumab in 42% of the patients. Paraproteinaemia incidence at 2 years was 32%. In univariate analysis paraproteinaemia was associated with unrelated donor, age, recipient seropositivity for CMV and alemtuzumab conditioning (hazard ratio (HR) 3.93, P=0.0006). Paraproteinaemia was not associated with haematological diagnosis; disease status at transplant; varicella zoster, herpes simplex or EBV serology; reduced-intensity vs myeloablative conditioning or GVHD. CMV reactivation-more frequent in alemtuzumab recipients-was associated with paraproteinaemia (HR 7.52, P<0.0001). In multivariate analysis, only increasing age (HR 1.04 per year, P=0.048) and CMV reactivation (HR 5.74, P=0.001) were significantly associated with paraproteinaemia. Alemtuzumab without CMV reactivation, however, resulted in significantly more paraproteinaemia, suggesting an effect that is independent of CMV reactivation. OS was poorer in patients with paraproteinaemia (HR 2.54, P=0.04) and relapse increased (HR 2.38, P=0.087). Paraproteinaemia was not significantly independently associated with decreased survival on multivariate analysis. Post transplant paraproteinaemia is associated with CMV reactivation, is more frequent in alemtuzumab-conditioned transplants and is not associated with improved OS.
...
PMID:Paraproteinaemia after allo-SCT, association with alemtuzumab-based conditioning and CMV reactivation. 2232 36

Although the use of nonmyeloablative (NMA) hematopoietic stem cell transplantation (HSCT) regimens has expanded in the past decade, little data exist to support antiviral prophylaxis to prevent herpes zoster (HZ) in recipients who are seropositive for varicella-zoster virus in this population. The present study examined the clinical features, incidence, and risk factors for HZ in a homogeneous cohort of NMA allogeneic HSCT recipients. We conducted a retrospective cohort study assessing all patients who underwent sibling NMA HSCT at Maisonneuve-Rosemont Hospital (Montreal) between July 2000 and December 2008. All patients received the same conditioning regimen, immunoprophylaxis, and graft-versus-host disease therapy. The diagnosis of HZ was defined clinically. Factors associated with HZ were identified using a Cox proportional hazards model. A total of 179 patients were followed for a median of 33 months (interquartile range, 21-59). HZ developed in 66 patients (37%) at a median of 8.3 months post-HSCT; the incidence rate was 175 cases/1000 person-years. The estimated cumulative HZ incidence was 27% at 1 year, 36% at 2 years, and 44% at 3 years. Thoracic dermatomes were most frequently involved (30%); dissemination occurred in 5 patients. No deaths resulted from HZ, but 23% of patients developed postherpetic neuralgia. In multivariate analysis, reactivation of cytomegalovirus and herpes simplex virus was associated with a reduced likelihood of HZ (hazard ratio, 0.54 and 0.33, respectively). Antiviral prophylaxis or treatment for cytomegalovirus and herpes simplex virus reactivations were protective against HZ. The incidence of HZ in our cohort of NMA HSCT recipients is similar to the incidence reported in HSCT recipients who received a myeloablative conditioning regimen. Given the observed high risk, we conclude that recommendations for antiviral prophylaxis should apply, at least for the first year, to the NMA HSCT population as well.
...
PMID:High incidence of herpes zoster in nonmyeloablative hematopoietic stem cell transplantation. 2097 44


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---