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Richard W Childs

Publications and source records attributed to Richard W Childs.

At least 19 recordsLinked to original sources
PubMed2007

Reduced intensity conditioning for allogeneic hematopoietic cell transplantation: current perspectives.

Allogeneic HCT after myeloablative conditioning is an effective therapy for patients with hematologic malignancies. In an attempt to extend this therapy to older patients or those with comorbidities, reduced intensity or truly nonmyeloablative regimens have been developed over the past decade. The principle underlying reduced intensity regimens is to provide some tumor kill with lessened regimen-related morbidity and mortality and then rely on graft-versus-tumor (GVT) effects to eradicate remaining malignant cells, whereas nonmyeloablative regimens rely primarily on GVT effects. In this article, 3 representative approaches are described, demonstrating the clinical application for hematopoietic and nonhematopoietic malignancies. Current challenges include controlling GVHD while allowing GVT to occur. In the future, clinical trials using reduced intensity and nonmyeloablative conditioning will be compared with myeloablative conditioning in selected malignancies to extend the application to standard-risk patients.

Graft vs Host Disease↗
PubMed2006

Cell labeling for magnetic resonance imaging with the T1 agent manganese chloride.

There is growing interest in using MRI to track cellular migration. To date, most work in this area has been performed using ultra-small particles of iron oxide. Immune cells are difficult to label with iron oxide particles. The ability of adoptively infused tumor specific T cells and N cells to traffic to the tumor microenvironment may be a critical determinant of their therapeutic efficacy. We tested the hypothesis that lymphocytes and B cells would label with MnCl2 to a level that would allow their detection by T1-weighted MRI. Significant signal enhancement was observed in human lymphocytes after a 1 h incubation with 0.05-1.0 mM MnCl2. A flow cytometry-based evaluation using propidium iodide and Annexin V staining showed that lymphocytes did not undergo apoptosis or necrosis immediately after and 24 h following a 1 h incubation with up to 1.0 mM MnCl2. Importantly, NK cells and cytotoxic T cells maintained their in vitro killing capacity after being incubated with up to 0.5 mM MnCl2. This is the first report to describe the use of MnCl2 to label lymphocytes. Our data suggests MnCl2 might be an alternative to iron oxide cell labeling for MRI-based cell migration studies.

Cell Movement↗
PubMed2006

Unique abnormalities of CD4(+) and CD8(+) central memory cells associated with chronic graft-versus-host disease improve after extracorporeal photopheresis.

Chronic graft-versus-host disease (cGVHD) remains a problematic complication of allogeneic hematopoietic stem cell transplantation. Laboratory parameters correlated with cGVHD have not been fully defined, although changes in CD4/CD8 ratios occur and a decrease in CD4(+) central memory T cells has been noted. Extracorporeal photopheresis (ECP) is an effective therapy for steroid-refractory cGVHD. We have noted changes in lymphocyte subsets after ECP. CD4(+) and CD8(+) T-cell central and effector memory populations were enumerated by flow cytometry in a cohort of 37 patients postallogeneic transplantation with symptomatic cGVHD. Of the patients with symptomatic cGVHD, 7 were treated with ECP over 6 months and prospectively assessed for changes in lymphocyte subsets. There was a highly significant correlation of an increase in CD8(+) central memory cells and a concomitant decrease in CD4(+) central memory cells in patients with symptomatic cGVHD. These changes were not detected in patients without cGVHD posttransplantation. In all, 7 patients with cGVHD followed up prospectively during ECP treatment showed a statistically significant normalization of the pattern of CD4(+) and a trend toward normalization of CD8(+) central memory T cells coincident with improvement of cGVHD. These data indicate a high correlation between disturbances in the balance of central and effector memory populations and cGVHD suggesting use in following up responses to therapy. The normalization of central and effector memory populations in response to ECP coincident with clinical improvement of cGVHD support a correlation between these laboratory parameters and cGVHD. Further studies are needed to demonstrate whether laboratory measurements of the magnitude of changes in central and effector memory populations are useful prognostically or can be used to guide response to therapy. The contrasting change in central memory cells (CD8(+) increased versus CD4(+) decreased) in cGVHD provide support for recent reports suggesting unique differences in the differentiation pathways for CD8(+) versus CD4(+) T cells.

Adult↗
PubMed2006

Accurate diagnosis of acute graft-versus-host disease using serum proteomic pattern analysis.

OBJECTIVE: The rapid diagnosis of acute graft-versus-host disease (GVHD) following allogeneic hematopoietic cell transplantation (HCT) is important for optimizing the management of this life-threatening complication. Current diagnostic techniques are time-consuming and require invasive tissue sampling. We investigated serum protein pattern analysis using surface-enhanced laser desorption ionization time-of-flight (SELDI-TOF) mass spectrometry as a tool to diagnose GVHD. PATIENTS AND METHODS: Eighty-eight serum samples were obtained from 34 patients undergoing HCT either pretransplant (n = 28 samples) or at various time points posttransplant (n = 60 samples), including 22 samples obtained on the day of onset of acute GVHD symptoms. Serum proteomic spectra generated from a "training set" of known samples were used to identify distinct proteomic patterns that best categorized a sample as either pretransplant, posttransplant non-GVHD, or GVHD; these distinct proteomic signatures were subsequently used to classify samples from a masked "test" sample set into the appropriate diagnostic category. RESULTS: Proteomic pattern analysis accurately distinguished GVHD samples from both posttransplant non-GVHD samples and pretransplant samples (100% specificity and 100% sensitivity in both cases). Furthermore, distinct serum proteomic signatures were identified that distinguished pretransplant from posttransplant non-GVHD samples (100% specificity and 94% sensitivity). CONCLUSION: These preliminary data suggest a potential application of SELDI-TOF-based proteomic analysis as a rapid and accurate method to diagnose acute GVHD.

Adult↗
PubMed2006

Overcoming graft rejection in heavily transfused and allo-immunised patients with bone marrow failure syndromes using fludarabine-based haematopoietic cell transplantation.

Allogeneic haematopoietic cell transplantation (HCT) can cure a variety of non-malignant haematological disorders. Although transplant outcomes for selected patients with severe aplastic anaemia (SAA) and paroxysmal nocturnal haemoglobinuria (PNH) have improved, older age, allo-immunisation from transfusions, prior immunosuppressive therapy and a prolonged time from diagnosis to transplantation are associated with worse outcome. Because of its potent immunosuppressive effects, we investigated a fludarabine-based non-myeloablative conditioning regimen in patients with transfusion-dependent non-malignant haematological disorders at increased risk for graft rejection with conventional transplant conditioning. Twenty-six patients with transfusion dependent/anti-thymocyte globulin (ATG)-refractory SAA, PNH or pure red cell aplasia underwent HCT from a human leucocyte antigen (HLA)-compatible relative. Transplant conditioning consisted of cyclophosphamide (120 mg/kg) and fludarabine (125 mg/m2) with or without ATG. Ciclosporine, alone or combined with mycophenolate mofetil or methotrexate, was used as graft-versus-host disease (GVHD) prophylaxis. All patients achieved durable engraftment and transfusion-independence. Twenty-four of 26 patients are alive at a median of 21 months following transplantation. Although a high cumulative incidence of acute (65% grades II-IV, 54% grades III-IV) and chronic GVHD (56%) was observed, only one patient died from transplant-related causes (cumulative incidence 7%). These data show that HCT following fludarabine-based non-myeloablative conditioning results in durable engraftment and excellent survival in SAA and PNH patients at high risk for graft rejection.

Adolescent↗
PubMed2004

Allogeneic hematopoietic cell transplantation for metastatic renal cell carcinoma after nonmyeloablative conditioning: toxicity, clinical response, and immunological response to minor histocompatibility antigens.

PURPOSE: This phase I trial assessed the safety, efficacy, and immunologic responses to minor histocompatibility antigens following nonmyeloablative allogeneic hematopoietic cell transplantation as treatment for metastatic renal cell carcinoma. EXPERIMENTAL DESIGN: Eight patients received conditioning with fludarabine and low-dose total body irradiation followed by hematopoietic cell transplantation from an HLA-matched sibling donor. Cyclosporine and mycophenolate mofetil were administered as posttransplant immunosuppression. Patients were monitored for donor engraftment of myeloid and lymphoid cells, for clinical response by serial imaging, and for immunologic response by in vitro isolation of donor-derived CD8(+) CTLs recognizing recipient minor histocompatibility (H) antigens. RESULTS: All patients achieved initial mixed hematopoietic chimerism with two patients rejecting their graft and recovering host hematopoiesis. Four patients developed acute, grade 2 to 3, graft-versus-host disease and four patients developed extensive chronic graft-versus-host disease. Five patients had progressive disease, two patients had stable disease, and one patient experienced a partial response after receiving donor lymphocyte infusions and IFN-alpha. CD8(+) CTL clones recognizing minor H antigens were isolated from five patients studied. Clones from three patients with a partial response or stable disease recognized antigens expressed on renal cell carcinoma tumor cells. CONCLUSIONS: Treatment of metastatic renal cell carcinoma with allogeneic hematopoietic cell transplantation after nonmyeloablative conditioning with fludarabine/total body irradiation is feasible and may induce tumor regression or stabilization in some patients. CD8(+) CTL-recognizing minor H antigens on tumor cells can be isolated posttransplant and could contribute to the graft-versus-tumor effect. Such antigens may represent therapeutic targets for posttransplant vaccination or adoptive T-cell therapy to augment the antitumor effects of allogeneic hematopoietic cell transplantation.

Adenocarcinoma, Clear Cell↗
PubMed2004

Nonmyeloablative transplantation: an allogeneic-based immunotherapy for renal cell carcinoma.

High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation has been explored as a method to enhance the efficacy of chemotherapy for advanced solid tumors. The failure of autologous hematopoietic stem cell transplantation to prolong survival in patients with metastatic solid tumors has sparked interest recently in studies exploring the potential of allogeneic hematopoietic stem cell transplantation for such patients. Allogeneic hematopoietic stem cell transplantation is widely accepted as a potent form of immunotherapy capable of curing patients with chemotherapy-refractory hematologic malignancies. However, it was not until the end of the 20th century that investigators initiated trials to test the potential of allogeneic hematopoietic stem cell transplantation as immunotherapy in malignancies of epithelial origin. Early pilot trials have established proof-of-principle that graft-versus-tumor effects can induce complete or partial remission in some treatment-refractory metastatic solid tumors. In this review, we discuss the rationale for pilot trials investigating the potential of nonmyeloablative allogeneic hematopoietic stem cell transplantation in advanced cytokine-refractory renal cancer, highlighting the preliminary success, limitations, and future clinical directions of this approach.

Carcinoma, Renal Cell↗
PubMed2004

Enhanced cytotoxicity of allogeneic NK cells with killer immunoglobulin-like receptor ligand incompatibility against melanoma and renal cell carcinoma cells.

Cellular inactivation through killer immunoglobulin-like receptors (KIRs) may allow neoplastic cells to evade host natural killer (NK) cell-mediated immunity. Recently, alloreactive NK cells were shown to mediate antileukemic effects against acute myelogenous leukemia (AML) after mismatched transplantation, when KIR ligand incompatibility existed in the direction of graft-versus-host disease (GVHD). Therefore, we investigated whether solid tumor cells would have similar enhanced susceptibility to allogeneic KIR-incompatible NK cells compared with their KIR-matched autologous or allogeneic counterparts. NK populations enriched and cloned from the blood of cancer patients or healthy donors homozygous for HLA-C alleles in group 1 (C-G1) or group 2 (C-G2) were tested in vitro for cytotoxicity against Epstein-Barr virus-transformed lymphoblastic cell lines (EBV-LCLs), renal cell carcinoma (RCC), and melanoma (MEL) cells with or without a matching KIR-inhibitory HLA-C ligand. Allogeneic NK cells were more cytotoxic to tumor targets mismatched for KIR ligands than their KIR ligand-matched counterparts. Bulk NK populations (CD3(-)/CD2(+)/CD56(+)) expanded 10(4)-fold from patients homozygous for C-G1 or C-G2 had enhanced cytotoxicity against KIR ligand-mismatched tumor cells but only minimal cytotoxicity against KIR ligand-matched targets. Further, NK cell lines from C-G1 or C-G2 homozygous cancer patients or healthy donors expanded but failed to kill autologous or KIR-matched MEL and RCC cells yet had significant cytotoxicity (more than 50% lysis at 20:1 effector-target [E/T] ratio) against allogeneic KIR-mismatched tumor lines. These data suggest immunotherapeutic strategies that use KIR-incompatible allogeneic NK cells might have superior antineoplastic effects against solid tumors compared with approaches using autologous NK cells.

Antigens, CD↗
PubMed2004

Severe chronic graft-versus-host disease is characterized by a preponderance of CD4(+) effector memory cells relative to central memory cells.

Donor alloreactive CD4(+) T cells are important to the pathogenesis of chronic graft-versus-host disease (cGVHD), but specific subsets of CD4(+) T cells responsible for GVHD have not been defined. We hypothesized that cGVHD might be associated with a preponderance of CD4(+) effector memory cells (CCR7(-)/CD62L(low), CD4(EM)). We analyzed CCR7 and CD62L expression on CD4(+) T cells from stem cell transplantation patients, who did or did not develop cGVHD, and healthy donors. Patients with cGVHD had a higher percentage of CD4(EM) cells (35.5% +/- 2.9%) than healthy donors (13.8% +/- 0.7%; P <.0001) or patients without cGVHD that received a transplant (21.7% +/- 2.1%; P <.01). Using corticosteroid dose as a surrogate marker for cGVHD severity, severe cGVHD was associated with a higher percentage of CD4(EM) cells. The proportion of CD4(EM) cells in corticosteroid-dependent patients with systemic lupus erythematosis or Wegener granulomatosis did not differ from patients without cGVHD that received a transplant. This finding implies that overrepresentation of CD4(EM) cells is a unique feature of cGVHD.

CD4-Positive T-Lymphocytes↗
PubMed2004

Nonmyeloablative allogeneic immunotherapy for solid tumors.

Over the past decade, considerable advances have been made in the field of allogeneic hematopoietic stem cell transplantation. Recognition that transplanted donor immune cells can cure patients with leukemia has led to the development of nonmyeloablative or "low-intensity" conditioning regimens, which have expanded the application of allogeneic transplantation to a growing number of hematological malignancies. The improved safety and preliminary success of this transplant approach have justified applying allogeneic immunotherapy to patients with treatment-refractory solid tumors.

Animals↗
PubMed2004

Nonmyeloablative transplantation for solid tumors: a new frontier for allogeneic immunotherapy.

The failure of conventional chemotherapy to improve survival in a large percentage of patients with advanced solid tumors has prompted the development of alternative anticancer approaches. Conventional allogeneic hematopoietic stem cell transplantation (HSCT) relies on myeloablative conditioning to eradicate the underlying disease, as well as suppress the patient's immune response, allowing engraftment of the donor's lymphohematopoietic system. Such preparative regimens are frequently associated with serious hematologic and nonhematologic toxicities, resulting in substantial morbidity and mortality. A significant curative component of allogeneic HSCT is the immune-mediated graft-versus-tumor (GVT) effect. Nonmyeloablative preparative regimens were designed to suppress host immunity to allow for sufficient engraftment of the donor immune system for the subsequent generation of GVT effects. These relatively low-dose preparative regimens are generally well tolerated and are associated with a reduction in the risk of transplant-related mortality. Nonmyeloablative HSCT provides a safer platform to explore the efficacy of allogeneic HSCT in patients with solid tumors. Initial reports have demonstrated that GVT may occur against several different solid tumors, including renal cell carcinoma, ovarian cancer, breast cancer and others. Based on these preliminary encouraging results, further exploration of nonmyeloablative HSCT for solid tumors is clearly warranted. The development of strategies to decrease graft-versus-host disease while enhancing post-transplant antitumor immunity will hopefully be forthcoming in the near future.

Graft vs Host Disease↗