Biomedical subjects
Publications and source records attributed to R K Burt.
In phase I (safety) trials, we have demonstrated the feasibility of autologous hematopoietic stem cell transplantation (HSCT) for patients with autoimmune diseases. Although this review comments on results of our phase I trials, the focus is on phase II (efficacy) trials using gene-marked autologous stem cells.
Allogeneic hematopoietic stem cell transplantation should be considered as a therapeutic option for patients with generalized erythoderma or tumor stage MF. Indeed, the only curative option for MF may be an allogeneic transplant. Bone Marrow Transplantation (2000) 25, 111-113.
Adoptive cellular therapy is developing as a supplement or alternative to chemotherapy and/or radiation for malignant disease. Our focus is two ongoing clinical studies with transgeneic (genetically altered) cellular therapy; one uses allogeneic (from another person) lymphocytes to treat leukemia, and the second uses xenogeneic (from another species) fibroblast cells genetically altered to contain a toxin-producing suicide gene to treat ovarian cancer. Allogeneic donor lymphocyte infusions (DLI) are known to induce remission of hematologic malignancies. However, the toxicity associated with DLI is related to graft-versus-host-disease, which is due to donor lymphocytes attacking normal tissue in the recipient. Therefore, we have taken the approach of infusing DLI that have been modified to contain a latent suicide gene to treat leukemia. To treat ovarian cancer, we used xenogeneic nonimmune fibroblast-derived cells to deliver a tumor-directed cytotoxic gene to carcinoma cells. These cells release HStk transgene retroviruses that in turn transduce replicating tumor cells but not quiescent epithelium, rendering the tumor selectively susceptible to ganciclovir-mediated killing. These initial trials summarize the early stage of allogeneic/xenogeneic adoptive cellular therapy for cancer, and although the data are limited, it is encouraging to see some patients with evidence of antitumor responses. Advances in our understanding of the basic science of these treatments, together with improvements in the technology of vector design, will be required to streamline these methodologies into broader application.
Adoptive cellular therapy is developing as a supplement or alternative to chemotherapy and/or radiation for malignant disease. Our focus is two ongoing clinical studies with transgeneic (genetically altered) cellular therapy; one uses allogeneic (from another person) lymphocytes to treat leukemia, and the second uses xenogeneic (from another species) fibroblast cells genetically altered to contain a toxin-producing suicide gene to treat ovarian cancer. Allogeneic donor lymphocyte infusions (DLI) are known to induce remission of hematologic malignancies. However, the toxicity associated with DLI is related to graft-versus-host-disease, which is due to donor lymphocytes attacking normal tissue in the recipient. Therefore, we have taken the approach of infusing DLI that have been modified to contain a latent suicide gene to treat leukemia. To treat ovarian cancer, we used xenogeneic nonimmune fibroblast-derived cells to deliver a tumor-directed cytotoxic gene to carcinoma cells. These cells release HStk transgene retroviruses that in turn transduce replicating tumor cells but not quiescent epithelium, rendering the tumor selectively susceptible to ganciclovir-mediated killing. These initial trials summarize the early stage of allogeneic/xenogeneic adoptive cellular therapy for cancer, and although the data are limited, it is encouraging to see some patients with evidence of antitumor responses. Advances in our understanding of the basic science of these treatments, together with improvements in the technology of vector design, will be required to stream-line these methodologies into broader application.
Theiler's murine encephalomyelitis virus (TMEV) establishes a persistent infection in the central nervous system (CNS) leading to an inflammatory demyelinating disease of the CNS in which the histology and clinical course is similar to multiple sclerosis (MS). Disease pathogenesis is primarily due to T-cell-mediated destruction of myelin, which has been attributed to cytopathic effects of the virus, but immune-mediated destruction of myelin mediated via both virus-specific and myelin-specific T cells appear to play the major role. To determine if bone marrow transplantation would be an effective therapy for a virus-initiated autoimmune disease and to better separate viral cytopathic effects from immune-mediated demyelination, we ablated the immune system of TMEV-infected animals with 1,100 cGy total body irradiation, and then the animal's immunity was reconstituted by transplantation of disease-susceptible SJL/J mice with syngeneic marrow or disease-susceptible DBA/2J with marrow from disease-resistant (C57Bl/6 x DBA/2)F1 (B6D2) donors. Hematopoietic transplant performed after onset of disease resulted in 42% mortality in SJL/J syngeneic transplants, 47% mortality in diseased DBA2 recipients restored with marrow from naive B6D2 donors, and 12% in diseased DBA2 recipients receiving marrow from B6D2 donors previously infected with TMEV. Delayed type hypersensitivity (DTH) to both virion and myelin proteins was decreased in surviving mice that underwent transplantation; however, CNS viral titers were significantly elevated compared with nontransplanted controls. We conclude that a functional immune system with appropriate T-cell responses are important in prevention of lethal cytopathic CNS effects from TMEV. Relevant to the clinical use of bone marrow transplantation, attempts to ablate the immune system in viral-mediated immune diseases or virus-initiated autoimmune disease may have acute and lethal consequences. Our results raise concern about the attempted use of autologous hematopoietic transplantation in patients with MS, an autoimmune disease with a suspected virus etiology, particularly if the graft is aggressively depleted of lymphocytes.
OBJECTIVE: To investigate the safety and efficacy of immune ablation with subsequent autologous hematopoietic stem cell transplantation (HSCT) in severe rheumatoid arthritis (RA). METHODS: Four patients with refractory RA and poor prognostic indicators were treated. Stem cells were collected and lymphocytes were depleted by 2.3-4.0 logs. The conditioning regimen included cyclophosphamide (200 mg/kg), antithymocyte globulin (90 mg/kg), and, for 1 patient, total body irradiation (TBI) with 400 cGy. Improvement was evaluated according to the American College of Rheumatology (ACR) preliminary definition of improvement in RA (ACR 20), and also according to the ACR 50 and ACR 70 criteria. RESULTS: HSCT was well tolerated. Three patients fulfilled the ACR 70 criteria at 1 month and 3 months post-HSCT. One patient did not fulfill the ACR 20 criteria because of persistent joint tenderness, despite improvement of the joint swelling. At 6 months post-HSCT, 1 patient fulfilled the ACR 70 criteria and 1 fulfilled the ACR 50 criteria, and these 2 patients fulfilled the ACR 70 criteria at 9 months post-HSCT. The other 2 patients (including the patient who received TBI) did not meet the ACR 20 criteria at 6 months and 9 months post-HSCT. The only patient with followup of >9 months fulfilled the ACR 70 criteria at 20 months post-HSCT. CONCLUSION: In this series, autologous HSCT was safe and effective in inducing major clinical response and maintained significant benefit for 2 patients at 9 months and 20 months posttreatment, respectively. Sustained response did not occur for 2 of 4 patients. A regimen dose-response effect may exist, but the addition of TBI did not prevent disease relapse for 1 of the patients. More aggressive T cell depletion of the autograft, use of a myeloablative regimen, or use of an allograft may be necessary to decrease relapse rates.
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Many different stem cell subsets have been identified. Some of these subsets are multipotent, able to develop into any one of several cell types, while other stem cell subsets are committed to differentiated myeloid, lymphoid, erythroid, or megakaryocytic lineages.
The overall goal of adoptive immunotherapy with genetically modified lymphocytes is to decrease the morbidity and mortality associated with allogeneic bone marrow transplantation. The initial data reviewed here suggest that the behavior of the allogeneic HStk transgenic cells can be modified after administration to patients. Further study is needed to identify the response rates and risks associated with this procedure. In particular, larger studies will be needed with appropriate randomization to determine if the response rate to genetically modified cells is equivalent to the response rates with unmodified cells. Wider application of these techniques in the initial setting of allogeneic transplantation will undoubtedly occur and such trials have been initiated at several institutions. Careful attention to vector, suicide gene, selectable marker, efficiency of transduction, and cell dose will be necessary when comparing different trials since these variables will probably affect transgenic cell survival and response rates. [figure: see text]
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Eleven patients with hematologic malignancies and two with aplastic anemia were treated using unmanipulated marrow and immunoselected CD34+ blood cells. Donors began G-CSF (10 microg/kg) injections 1 day after undergoing bone marrow harvest. Blood stem cells were collected on day 5 of G-CSF. Peripheral blood lymphocytes were depleted via CD34-positive selection. If, after marrow and blood harvest, less than 2.0 x 10(6) CD34 cells/kg were mobilized, leukapheresis was repeated on day 6. Median time to an absolute neutrophil count greater than 500 microl was day 10; transfusion-independent platelet count greater than 20,000/microl was day 13; average hospital discharge was day 14; and average inpatient hospital charges were 101,870 US dollars. Acute GVHD grade II occurred in five of 13 patients. No patient developed grade III or IV acute GVHD. At a median follow-up of 10 months, no patient has developed extensive chronic GVHD. Allografts of unmanipulated bone marrow supplemented with G-CSF-mobilized and CD34 immunoselected blood cells may prevent an increased risk of GVHD while preserving the rapid engraftment kinetics of peripheral blood. Supplementation of marrow with CD34 enriched blood cells appears to result in rapid engraftment, early hospital discharge, lower inpatient charges, decreased regimen-related toxicity, and no apparent increase in GVHD.
Patients with recurrent leukemia after an allogeneic hematopoietic stem cell transplant may be treated with donor lymphocyte infusions (DLI). The transfusion of lymphocytes from the original hematopoietic stem cell donor induces remission in approximately one third of relapsed AML cases and 80% of relapsed CML. DLI may be complicated by delayed and sometimes lethal graft-versus-host disease (GVHD). In an attempt to avoid this complication, several centers have initiated DLI trials in which the infused lymphocytes carry a suicide gene, herpes simplex thymidine kinase (HStk), which confers sensitivity to ganciclovir (GCV). In the event of severe GVHD, administration of GCV should terminate or ameliorate GVHD.
OBJECTIVE: For patients with systemic lupus erythematosus (SLE) who are at risk of disease-related mortality, we have initiated a protocol of intensive immunosuppression and haematopoietic stem cell support. The first patient enrolled in this study was in the midst of a lupus flare manifest by nephritis and rapidly declining renal function, uncontrolled hypertension, immune-mediated cytopenias, and serositis characterized by a large pericardial effusion and abdominal pain. Antinuclear antibody (ANA), anti-double-stranded (ds) DNA and complement were abnormal. This patient is now more than 1 yr post-stem cell transplant and is taking no immunosuppressive medication. Her serologies are normal, effusions have resolved, blood pressure is normal and renal function is markedly improved. The clinical and serological course of this patient is summarized here. METHODS: Autologous haematopoietic stem cells (HSC) were mobilized with cyclophosphamide (2.0 g/m2) and granulocyte colony-stimulating factor (G-CSF) (10 microg/kg/day). Stem cells were enriched ex vivo using CD34-positive immunoselection and reinfused after immunosuppression with cyclophosphamide (200 mg/kg) and antithymocyte globulin (ATG) (90 mg/kg). RESULTS: White blood cell engraftment with an absolute neutrophil count (ANC) of >500/microl (0.5 x 10(9)/l) and platelet engraftment with a non-transfused platelet count of >20000/microl (20 x 10(9)/l) occurred on day 10 and 14, respectively. Therapy was complicated by a cell lysis-like effect with hyperphosphataemia, hyperuricaemia, normal anion gap metabolic acidosis and transient exacerbation of renal insufficiency. CONCLUSION: This is the first autologous T-cell-depleted haematopoietic stem cell transplantation performed to treat lupus in an active flare. This patient has, for the first time since discase onset (13 yr ago), entered a complete clinical and serological remission which persists at >1 yr of follow-up. The durability of this remission is unknown.
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Multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis are immune-mediated diseases that are responsive to suppression or modulation of the immune system. For patients with severe disease, immunosuppression may be intensified to the point of myelosuppression or hematopoietic ablation. Hematopoiesis and immunity may then be rapidly reconstituted by reinfusion of CD34(+) progenitor cells. In 10 patients with these autoimmune diseases, autologous hematopoietic stem cells were collected from bone marrow or mobilized from peripheral blood with either granulocyte colony-stimulating factor (G-CSF) or cyclophosphamide and G-CSF. Stem cells were enriched ex vivo using CD34(+) selection and reinfused after either myelosuppressive conditioning with cyclophosphamide (200 mg/kg), methylprednisolone (4 g) and antithymocyte globulin (ATG; 90 mg/kg) or myeloablative conditioning with total body irradiation (1,200 cGy), methylprednisolone (4 g), and cyclophosphamide (120 mg/kg). Six patients with multiple sclerosis, 2 with systemic lupus erythematosus, and 2 with rheumatoid arthritis have undergone hematopoietic stem cell transplantation. Mean time to engraftment of an absolute neutrophil count greater than 500/microL (0.5 x 10(9)/L) and a nontransfused platelet count greater than 20,000/microL (20 x 10(9)/L) occurred on day 10 and 14, respectively. Regimen-related nonhematopoietic toxicity was minimal. All patients improved and/or had stabilization of disease with a follow-up of 5 to 17 months (median, 11 months). We conclude that intense immunosuppressive conditioning and autologous T-cell-depleted hematopoietic transplantation was safely used to treat these 10 patients with severe autoimmune disease. Although durability of response is as yet unknown, all patients have demonstrated stabilization or improvement.
Relapsing experimental autoimmune encephalomyelitis (R-EAE) is an immune-mediated demyelinating central nervous system (CNS) disease. Myeloablation and syngeneic bone marrow transplantation (SBMT), when performed at the peak of acute disease (day 14), prevented glial scarring and ameliorated the disease severity. In contrast, when syngeneic BMT was performed late in chronic phase (day 78), significant glial scarring remained and the clinical severity did not differ significantly from that of the controls. After SBMT in either the acute or chronic phase of disease, the posttransplant immune system remained responsive to myelin epitopes as determined by in vitro proliferation and interferon-gamma (IFN-gamma) production. However, in mice undergoing SBMT, in vivo delayed-type hypersensitivity (DTH) responses were significantly decreased while IFN-gamma RNA levels and inflammatory infiltrates within the CNS were slightly improved. We conclude that failure of SBMT to improve the clinical disease when performed in chronic phase may be due to preexisting glial scarring. We also conclude that in the absence of glial scarring and irreversible neuronal injury, in vivo DTH responses and histology are better predictors of clinical improvement than in vitro proliferation or IFN-gamma cytokine production.
This study will evaluate the safety and efficacy of allogenic donor lymphocyte infusions in patients who have relapsed hematologic malignancies after allogeneic bone marrow transplantation (BMT). Donor lymphocyte transfusions have resulted in the cure of some patients with relapsed leukemia or lymphoproliferative disorder after allogeneic BMT, but has been complicated by the development of graft versus host disease (GvHD). We hypothesize that a retroviral vector containing the Herpes simplex thymidine kinase (HStk) gene will allow for retention of the anti-leukemia response of transfused donor lymphocytes while allowing for the adverse effects of GVHD to be mitigated. Patients with relapsed hematologic malignancies after allogeneic BMT will be infused with ex vivo gene modified donor lymphocytes. The Herpes Simplex thymidine kinase (HStk) gene will be transduced into the cells ex vivo using LTKOSN. 1 vector supernate. Insertion of the HStk gene into lymphocytes confers a sensitivity to the anti-herpes drug ganciclovir (GCV). This selective destruction of donor lymphocytes in situ will be used to abrogate the effect of graft versus host disease, if it develops.