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Biomedical subjects

A P Gee

Publications and source records attributed to A P Gee.

At least 19 recordsLinked to original sources
PubMed2005

T-cell immunotherapy for adenoviral infections of stem-cell transplant recipients.

Human adenoviruses are ubiquitous lytic DNA viruses that can be divided into 51 different serotypes, grouped from A to F on the basis of genome size, composition, homology, and organization. Adenovirus infections, although frequent, are rarely fatal in immunocompetent individuals, due to potent innate and adaptive immune responses. By contrast, adenoviruses are a significant cause of morbidity and mortality in immunosuppressed individuals, for whom there are limited treatment options. Since antiviral drugs have variable efficacy in the treatment of severe adenovirus disease, iatrogenic reconstitution with in vitro expanded virus-specific cytotoxic T lymphocytes (CTLs) is an attractive option for prophylaxis and treatment, particularly because the endogenous recovery of adenovirus-specific T cells has proved important in controlling infection in vivo. Thus, we have characterized human T-cell responses to adenovirus in vitro and explored the potential of adoptive T-cell immunotherapy as a prophylactic or therapeutic strategy for adenovirus infections posttransplant.

Adenoviridae Infections↗
PubMed2004

Bone marrow transplantation from partially HLA-mismatched family donors for acute leukemia: single-center experience of 201 patients.

Between February 1993 and December 1999, 201 patients (1-59 years old, median 23) with acute leukemia (67% not in remission) underwent ex vivo T-cell-depleted (TCD) bone marrow transplants (BMT) from partially mismatched related donors (PMRD; 92% mismatched for 2-3 HLA A, B, DR antigens). Conditioning comprised total body irradiation, cyclophosphamide, cytarabine, etoposide, anti-thymocyte globulin (ATG), and methylprednisolone. Graft-versus-host disease (GVHD) prophylaxis comprised partial TCD with OKT3 (n=143) or T10B9 (n=58), steroids, ATG, and cyclosporine. The engraftment rate was 98%. The cumulative incidences of grades II-IV acute GVHD and chronic GVHD were 13 and 15%, respectively. The 5-year cumulative incidences of relapse and transplant-related mortality (TRM) were 31 and 51%, respectively. The actuarial 5-year overall survival (OS) and disease-free survival (DFS) probabilities were 19 and 18%, respectively. Patient age >15 years, active disease at transplant, donor age >25 years, and 3-antigen donor mismatch (host-versus-graft) affected the outcome adversely. The actuarial 5-year OS of four groups of patients identified based upon these risk factors was 39, 20, 13, and 0%, respectively (P<0.0001). We conclude that PMRD BMT is a potential treatment option for patients with high-risk acute leukemia who require an alternative donor transplant and fall into a group with a reasonable expected outcome.

Acute Disease↗
PubMed2003

Gene transfer: regulatory issues and their impact on the clinical investigator and the good manufacturing production facility.

The first human gene-transfer study was submitted to the Recombinant DNA Advisory Committee (RAC) in 1988, thus initiating a new era in clinical research. As per the RAC Website (last updated 22nd November 2002), almost 550 human gene-transfer studies have been submitted to the RAC. However, there are currently no licensed gene-therapy products available in the USA. The natural evolution of the review process to accommodate these novel protocols, as well as the death of Jesse Gelsinger in 1999, have led to significant changes in the initial and ongoing review of gene-transfer studies. However, the basic framework of the review process remains unchanged.Gene-transfer protocols require oversight by the Food and Drug Administration (FDA), the Recombinant DNA Advisory Committee (RAC), the Institutional Biosafety Committee (IBC), and the Institutional Review Board (IRB). Such oversight includes both initial review of the protocol and ongoing review of the study through the review of annual reports, adverse events, and proposed amendments to the study. In addition to such review of the protocol, the product itself is required by the FDA to be prepared under current good manufacturing practices (cGMP). This article discusses both regulatory oversight and current GMP issues in depth.

Biological Products↗
PubMed2002

In vitro interactions between gamma deltaT cells, DC, and CD4+ T cells; implications for the immunotherapy of leukemia.

BACKGROUND: Gamma deltaT cells contribute to immune defense against infectious organisms and some malignancies, but the process of activation and proliferation of these cells is not well understood. It is known that the immune response of gamma deltaT cells is not MHC-dependent, but is likely based on direct recognition of surface peptides and non-peptide ligands. This study examined whether DCs and CD4(+) T cells can participate in the activation of gamma deltaT cells. METHOD: Peripheral blood gamma deltaT cells were co-cultured with CD34-derived autologous DCs and CD4(+) T cells using contact-dependent cultures and transwell systems. Proliferation, immunophenotyping, and cytotoxicity assays determined the extent of gamma deltaT cell proliferation and cytotoxicity. RESULTS: Human gamma deltaT cells expanded 221.3 +/- 76-fold in cultures with DCs, and 165.7 +/- 76.6-fold with CD4(+) T-cells alone. Proliferation was enhanced (1949.8 +/- 261.3-fold) when gamma deltaT cells were cultured with both DC and CD4(+) T cells. Proliferation was contact-dependent, and resulted in the expansion of V delta1+ or V delta2+ cells cytotoxic against several leukemic cell-lines, but not against allogeneic PHA-induced lymphoid blasts. Ligation of the T-cell receptor with anti-pan-delta Ab significantly up-regulated cytotoxicity against K562, KBM-5 and KG1a, and normal BM, but not against Molt-4, allogeneic EBV-transfected B cells and allogeneic PHA-blasts. Minimal cytotoxic activity was shown against allogeneic marrow colony-forming units granulocyte-macrophage and erythrocyte colony-forming units. CONCLUSION: DCs can participate in the activation of gamma deltaT cells against specific autologous targets, and cytotoxicity can be enhanced by further stimulation via the T-cell receptor.

CD11c Antigen↗
PubMed2001

Generation of autologous Epstein-Barr virus-specific cytotoxic T cells for adoptive immunotherapy in solid organ transplant recipients.

BACKGROUND: Epstein-Barr virus (EBV)-driven posttransplant lymphoproliferative disorders (PTLD) affect 2%-27% of solid organ transplant (SOT) recipients. Adoptive immunotherapy may have therapeutic potential in this setting, but there is little experience in generating autologous EBV-specific cytotoxic T-cell lymphocytes (EBV-CTLs) from SOT recipients, and their efficacy and persistence in an immunosuppressed environment is unknown. METHODS: EBV-CTLs were generated from eight SOT recipients, using weekly stimulations with autologous lymphoblastoid cell lines (LCLs) and interleukin-2. CTL phenotype and function were evaluated in the presence of therapeutic concentration of cyclosporin A or FK506. RESULTS: In all cases, CTLs expanded with normal kinetics. The majority was CD3+CD8+ (mean, 76%), with less than 3% of natural killer cells. All ex vivo-generated CTLs produced significantly higher killing of autologous LCLs than of HLA-mismatched LCLs (mean, 56% vs. 14% at 20:1 ratio). No lysis of autologous or allogeneic PHA blasts was observed. The CTL expansion rate was reduced in a concentration-dependent manner in the presence of immunosuppressive drugs; however, neither lytic activity nor phenotype was affected. CONCLUSIONS: Using methods that are approved for clinical application, EBV-CTLs can be generated from SOT recipients, even those with frank lymphoma, or who are receiving immunosuppressive drugs. These CTLs retain their function in the presence of immunosuppressive agents. Although in vivo efficacy, safety, and persistence can be assessed only in clinical trials, our results suggest that CTLs can be effective for the treatment of PTLD, even when immunosuppression cannot be reduced because of the high risk of graft rejection.

Antibody Specificity↗
PubMed2000

High CD34 cell doses do not worsen regimen-related toxicity or early mortality after autologous blood stem cell transplantation for breast cancer.

BACKGROUND: Some transplant-related complications, such as the engraftment syndrome, are thought to be mediated by cytokines released during expansion of hematopoietic progenitors at the time of neutrophil recovery. Since there is an inverse correlation between CD34(+) cell dose and time to neutrophil recovery, we sought to determine if peritransplant toxicity and early mortality were adversely affected by high CD34(+) cell doses. METHODS: The study group included 186 women with breast cancer who received high-dose cyclophosphamide, carmustine, thiotepa and an autologous PBSC transplant. The median CD34(+) cell dose was 5.9 x 10(6)/kg (1.0-154.7 x 10(6)/kg). Patients were categorized by CD34(+) cell dose (1.0-3.5, 3.6-5.9, 6.0-19.9, and 20.0-154.7 x 10(6)/kg) for assessment of outcomes. RESULTS: Grades 2-4 mucositis occurred in 49%, cardiac toxicity in 7%, pulmonary toxicity in 5%, cystitis in 4%, diarrhea in 3%, renal toxicity in 1%, and central nervous system toxicity in 1%. A Grade 2-4 regimen-related toxicity occurred in 109 patients (59%) and Grade 3-4 in eight patients (4%). Overall survival was 100% at Day 30, 96% at Day 90, and 89% at 1 year. Treatment-related mortality was 3.8%. In multivariate analyses that included prior chemotherapy, disease status, visceral metastases, prior chest radiation and age, CD34(+) cell dose group was not an independent risk factor for Grade 2-4 mucositis, Grade 2-4 maximum toxicity, Grade > or =3 cumulative toxicity, 90 day survival or 1 year survival. DISCUSSION: We conclude that CD34(+) cell doses >20 x 10(6)/kg do not affect transplant outcome in a negative or positive fashion.

Adult↗
PubMed2000

Partially mismatched related-donor bone marrow transplantation for pediatric patients with acute leukemia: younger donors and absence of peripheral blasts improve outcome.

PURPOSE: To extend access to bone marrow transplantation (BMT), we used partially mismatched related donors (PMRD) for pediatric patients with acute leukemia. In this report we sought to determine pretransplantation factors that might predict outcome. PATIENTS AND METHODS: Of 67 such patients, 43 had acute lymphocytic leukemia and 24 had acute myelogenous leukemia. At the time of transplantation, 41 patients were in relapse. Donors included 40 parents, 24 siblings, and three cousins. HLA disparity of two to three major antigens was detected in two thirds of the donor-recipient pairs. Conditioning therapy, including total-body irradiation and chemotherapy followed by graft-versus-host disease (GvHD) prophylaxis with partial T-cell depletion of the graft using T10B9 or OKT3, was combined with posttransplantation immunosuppression. RESULTS: Estimated probability (EP) of engraftment was 0.96 and was not affected by donor-antigen mismatch (AgMM; P =.732). EP of grades 2 to 4 acute GvHD was 0.24 and was not affected by recipient AgMM (P =.796). EP of disease-free survival was 0.26 at 3 years but improved to 0.45 when donors were younger than 30 years (P<.001). EP of relapse at 3 years was 0.41 and reduced with younger donors' age. For patients who were in relapse at the time of transplantation, absence of blasts was associated with a lower relapse rate (0.46 v. 0.84; P =. 083), similar to that of patients in remission. CONCLUSION: PMRD-BMT in pediatric leukemia resulted in high engraftment and low GvHD rates. To improve outcomes, younger donors should be sought, and clinicians should attempt to reduce peripheral blasts in patients who are in relapse.

Adolescent↗
PubMed1999

Expression of CD134 (0X-40) on T cells during the first 100 days following allogeneic bone marrow transplantation as a marker for lymphocyte activation and therapy-resistant graft-versus-host disease.

CD134 (OX-40) is an activation-associated antigen which functions as a costimulatory receptor for CD4+ T cells. In order to determine the expression of CD134 during immune recovery following allogeneic bone marrow transplantation (BMT), we measured its expression on T cells and T cell subsets during the first 100 days following BMT in 26 patients. CD4+CD134+ T could be seen approximately 14 days following BMT cells in patients who did not develop GvHD which required therapy (n = 20). The percentage of CD4+CD134+ cells continued to increase up to the fourth week following BMT to a maximum of 40-50% of CD4+ T cells (normal = 1-8%). Two patients who developed Grade I-II GvHD and who responded to treatment with pulsed high-dose methylprednisolone (MPD) showed a decline of approximately 40% in CD4+CD134+ T cells was seen within 48 hours of treatment. Four patients who developed GvHD that was not responsive to MPD and who later developed high IV GvHD showed increasing CD4+CD134+ T cells up to 85% of the CD4+ T cells. Additionally, rapid increases in CD134+ T cells following antibody-based T cell therapy were associated with GvHD recurrence. In no cases was the percentage of CD134+ CD4+ T cells predictive of clinical GvHD. In this exploratory study, we have shown that CD134, although not predictive of the initial onset of GvHD, may be a useful tool for monitoring the response to early GvHD therapy and identification of patients at risk for reemergence of GvHD who may benefit from anti-T cell therapy. Cytometry (Comm. Clin. Cytometry) 38: 238-243, 1999.

Biomarkers↗
PubMed1999

Allogeneic blood progenitor cell collection in normal donors after mobilization with filgrastim: the M.D. Anderson Cancer Center experience.

BACKGROUND: Information on the safety and efficacy of allogeneic peripheral blood progenitor cell (PBPC) collection in filgrastim-mobilized normal donors is still limited. STUDY DESIGN AND METHODS: The PBPC donor database from a 42-month period (12/94-5/98) was reviewed for apheresis and clinical data related to PBPC donation. Normal PBPC donors received filgrastim (6 microg/kg subcutaneously every 12 hours) for 3 to 4 days and subsequently underwent daily leukapheresis. The target collection was > or =4 x 10(6)CD34+ cells per kg of recipient's body weight. RESULTS: A total of 350 donors were found to be evaluable. Their median age was 41 years (range, 4-79). Their median preapheresis white cell count was 42.8 x 10(9) per L (range, 18.3-91.6). Of these donors, 17 (5%) had inadequate peripheral venous access. Leukapheresis could not be completed because of apheresis-related adverse events in 2 donors (0.5%). Of the 324 donors evaluable for apheresis yield data, 221 (68%) reached the collection target with one leukapheresis. The median CD34+ cell dose collected (first leukapheresis) was 462 x 10(6) (range, 29-1463). The main adverse events related to filgrastim administration in donors evaluable for toxicity (n = 341) were bone pain (84%), headache (54%), fatigue (31%), and nausea (13%). These events were rated as moderate to severe (grade 2-3) by 171 (50%) of the donors. In 2 donors (0.5%), they prompted the discontinuation of filgrastim administration. CONCLUSION: PBPC apheresis for allogeneic transplantation is safe and well tolerated. It allows the collection of an "acceptable" PBPC dose in most normal donors with one leukapheresis, with minimal need for invasive procedures.

Adolescent↗
PubMed1998

Phenotypic and functional reconstitution of peripheral blood lymphocytes following T cell-depleted bone marrow transplantation from partially mismatched related donors.

Myeloablative chemotherapy followed by transplantation of a T cell-depleted bone marrow graft from a partially mismatched related donor provides a potentially curative option for patients with leukemia and other disorders of hematopoiesis, although the patient is faced with a period of sustained immunodeficiency as well as pharmacologic immunosuppression as a result of prophylaxis against graft-versus-host disease. Thirty patients who received one to three antigen T cell-depleted mismatched grafts were evaluated for immune reconstitution. The percentage and numbers of cells expressing lymphocyte subset antigens were determined by flow cytometry at 14, 28, 60, 100, 180, 270 and 365 days post-BMT and at 6 month intervals thereafter. Lymphocyte reconstitution was characterized by the early appearance of natural killer cells and a low percentage of both T and B cells. During the first year after BMT, the number of NK cells remained constant while T and B cells gradually returned to normal numbers and proportions. Response to the lymphocyte mitogen phytohemagglutinin returned to normal over the course of 2 years, while the response to concanavalin A was slightly depressed and the response to pokeweed mitogen became supranormal at about 1.5 years and continued to increase. These data suggest the need for long-term immunophenotypic monitoring as well as prolonged infection surveillance and prophylaxis.

B-Lymphocytes↗
PubMed1998

Donor leukocyte infusion for treatment of graft rejection post partially mismatched related donor bone marrow transplant.

Graft rejection following bone marrow transplantation is more common in patients who receive their grafts from alternative donors and whose marrow is T cell depleted. Rejection in these patients is mediated by persistent host cells that interfere with successful establishment of donor-derived hematopoietic recovery. We describe a patient with chronic myelogenous leukemia in accelerated phase who rejected a T cell-depleted bone marrow graft, 2 months following partially mismatched related donor bone marrow transplant. Unmanipulated peripheral blood donor leukocyte infusion, without additional chemotherapy or immunosuppressive therapy resulted in complete hematopoietic recovery. Cytogenetics and RFLP demonstrated hematopoietic donor chimerism. The patient did not develop graft-versus-host disease.

Adult↗
PubMed1997

Use of partially mismatched related donors extends access to allogeneic marrow transplant.

Most patients requiring allogeneic bone marrow transplant (allo-BMT) do not have an HLA-matched sibling donor. A phenotypically matched unrelated donor graft has been made available for approximately 50% of Caucasians and less than 10% of ethnic and racial minorities in need. However, almost all patients have a readily available partially mismatched related donor (PMRD). We summarize our experience with 72 patients who ranged from 1 to 50 years of age (median, 16 years) and who were recipients of a PMRD allo-BMT from haploidentical family members following conditioning therapy using total body irradiation (TBI) and multiagent, high-dose chemotherapy. T-cell depletion and post-BMT immunosuppression were combined for graft-versus-host disease (GVHD) prophylaxis. The probability of engraftment was 0.88 at 32 days. Six of 10 patients who failed to engraft achieved engraftment after secondary transplant. Grade II to IV acute GVHD was seen in 9 of 58 (16%) evaluable patients; extensive chronic GVHD was seen in 4 of 48 (8%) evaluable patients. There was a statistically significant difference in 2-year survival probability between low-risk and high-risk patients (0.55 v 0.27, P = .048). Prognostic factors that affected outcomes in multivariate analysis were (1) a lower TBI dose and 3-antigen rejection mismatch decreased stable engraftment (P = .005 and P = .002, respectively); (2) a higher T-cell dose increased acute GVHD (P = .058); (3) a higher TBI dose increased chronic GVHD (P = .016); and (4) a high-risk disease category increased treatment failure from relapse or death (P = .037). A PMRD transplant can be performed with acceptable rates of graft failure and GVHD. Using sequential immunomodulation, the disease status at the time of transplant is the only prognostic factor significantly associated with long-term successful outcome after PMRD allo-BMT. When allogeneic rather than autologous BMT is indicated, progression in disease status before transplant can be avoided using a PMRD with equal inclusion of all ethnic or racial groups.

Acute Disease↗
PubMed1997

Flow cytometric cell sorting combined with molecular chimerism analysis to detect minimal recurrent leukemia: good news and bad news.

Allogeneic BMT offers the possibility of cure for a variety of hematopoietic malignancies, but disease relapse remains a major cause of treatment failure. This report describes two cases in which flow cytometric cell sorting (FACS) and molecular chimerism analysis were combined to increase the sensitivity of minimal residual disease (MRD) detection. In the first case this approach was used to demonstrate that a suspicious phenotype was not recurrent leukemia, thus preventing the use of potentially toxic therapy. In the second case the recurrence of a leukemia which was undetectable by conventional analysis was confirmed. The potential benefits of combining these MRD detection methods are discussed.

Adolescent↗
PubMed1996

Bone marrow metastases.

This article discusses the clinical significance of bone marrow metastases and the current methods being used to detect tumor cells in marrow. The strategies being investigated for eradicating cancer cells from marrow in patients receiving hematopoietic cell autografts also are reviewed.

Bone Marrow Neoplasms↗
PubMed1996

Increased frequency of TCR gamma delta + T cells in disease-free survivors following T cell-depleted, partially mismatched, related donor bone marrow transplantation for leukemia.

Recent interest has focused on the function of gamma delta + T cells in immune responses. However, their role in allogeneic bone marrow transplantation (BMT) remains undefined. We report on a group of 43 leukemia patients who survived for at least 100 days following transplantation using partially HLA-mismatched grafts from related donors that were T cell depleted with the anti-TCR alpha beta monoclonal antibody T10B9.1A-31 and complement. Ten patients (23.2%) were found to have an increased (> or = 10%) proportion of gamma delta + T cells in the peripheral blood at 60-270 days after BMT. All of these patients remain alive, and 9 (90% of patients with > or = 10% gamma delta + cells) are free of disease at 2.5 years compared with a disease-free survival probability of 31% among patients with a normal proportion and concentration of gamma delta + T cells. No other factor was found to be independently associated with improved survival in these patients. These data suggest a possible association between an increase in the percentage and number of gamma delta + T cells and improved disease-free survival following transplantation from a partially mismatched related donor.

Bone Marrow Transplantation↗