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Biomedical subjects

Christian Chabannon

Publications and source records attributed to Christian Chabannon.

17 recordsLinked to original sources
PubMed2006

Purification of monocytes from cryopreserved mobilized apheresis products by elutriation with the Elutra device.

The Elutra biomedical device allows semi-automatic enrichment of monocytes by elutriation, using a single-use, closed and cGMP compliant tubing set, in a cost effective way. The procedure has been validated using fresh apheresis products from nonmobilized donors. We here evaluated the possibility of using Elutra to enrich monocytes from frozen/thawed apheresis products collected from mobilized healthy donors. Frozen apheresis products from 6 G CSF mobilized donors were thawed and used in 16 elutriation procedures. We compared the recovery and purity of enriched monocytes using different buffer compositions and elutriation profiles. Elutriated monocytes were cultured to generate mature dendritic cells (DCs). Depending in part of the initial granulocyte contamination in the apheresis product, the use of Desoxyribo Nuclease (DNAse) to avoid aggregation, was needed through only the initial steps or throughout the elutriation process. The average monocyte recovery was 85+/-31%. The average purity was 73+/-9%. The recovery of mature DC at d8 of culture was 20+/-6% of the input monocyte numbers. We conclude that Elutra allows the purification of monocytes from thawed mobilized apheresis. It requires no pre-processing of the cell product before elutriation, and allows the generation of phenotypically mature DC in quantities that are compatible with a clinical use.

Antigens, CD↗
PubMed2006

CD99 expressed on human mobilized peripheral blood CD34+ cells is involved in transendothelial migration.

Hematopoietic progenitor cell trafficking is an important phenomenon throughout life. It is thought to occur in sequential steps, similar to what has been described for mature leukocytes. Molecular actors have been identified for each step of leukocyte migration; recently, CD99 was shown to play a part during transendothelial migration. We explored the expression and role of CD99 on human hematopoietic progenitors. We demonstrate that (1) CD34+ cells express CD99, albeit with various intensities; (2) subsets of CD34+ cells with high or low levels of CD99 expression produce different numbers of erythroid, natural killer (NK), or dendritic cells in the in vitro differentiation assays; (3) the level of CD99 expression is related to the ability to differentiate toward B cells; (4) CD34+ cells that migrate through an endothelial monolayer in response to SDF-1alpha and SCF display the highest level of CD99 expression; (5) binding of a neutralizing antibody to CD99 partially inhibits transendothelial migration of CD34+ progenitors in an in vitro assay; and (6) binding of a neutralizing antibody to CD99 reduces homing of CD34+ progenitors xenotransplanted in NOD-SCID mice. We conclude that expression of CD99 on human CD34+ progenitors has functional significance and that CD99 may be involved in transendothelial migration of progenitors.

12E7 Antigen↗
PubMed2006

[The consortium of Biological Resource Centres (BRC) and tumour cell and tissue banks in the Marseilles metropolitan area].

The goal of this presentation is to describe current and future aspects of the operations within the consortium of Biological Resource Centres (BRC) and Tumour cell and tissue banks of the Marseilles metropolitan area. The consortium was created in year 2001, through the association of several tissue and cell banks that were operating for many years in Marseilles. Existing collections are not exclusively collections of tumour cells or tissues; however, the two tumour cell and tissue banks located at the Regional Cancer Research Centre and at the University Hospital account for a very significant proportion of the collections. Our collective work leads to the recognition and funding of the consortium by Inserm, through the "Collections 2003" grant. The consortium objectives are to define a common scientific strategy, to share professional practices in the logistics and database management of the banks, to establish a quality management program, and to build a common catalogue that describes existing biological resources. Through these efforts, the ultimate goal is to adopt rules that define BRC, as defined by the Organization for Economic Co-operation and Development (OECD).

France↗
PubMed2006

[G-CSF in oncology].

Neutropenia and its subsequent infectious complications represent the most common dose-limiting toxicity of cancer chemotherapy. Febrile neutropenia (FN) occurs with common chemotherapy regimens in 25 to 40 % of treatment-naive patients, and its severity depends on the dose intensity of the chemotherapy regimen, the patient's prior history and comorbidities. Neutropenia is associated with the risk of life-threatening infections as well as chemotherapy dose reductions and delays that may compromise treatment outcome. One of the first, most important and sustained applications of recombinant DNA technology in medicine was the cloning and introduction into clinical practice of several glycoprotein factors involved in the regulation of hematopoiesis. Colony-stimulating factors (CSFs) such as granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are now an integral part of the prevention of potentially life-threatening FN. Important uses of CSFs in oncology are prevention of FN after chemotherapy, treatment of FN, collection of CSF-mobilised peripheral stem cells and support following peripheral stem cells transplantation. This article reviews the data supporting the clearly clinical applications of CSFs in oncology.

Antineoplastic Agents↗
PubMed2005

[Happy birthday, CD34!].

Twenty years after the initial description of the CD34 antigen, scientists are still interested in elucidating the exact function of a prototypic << stem cell antigen >> in human, primate and mouse models. While this question remains largely unresolved, this has not precluded the development of medical tools using the detection of CD34 in several applications that range from diagnosis of malignant blood diseases through the biological monitoring of haematopoietic cell collection for autologous or allogeneic transplantation. This review focuses on major aspects of CD34 biology.

Animals↗
PubMed2005

Clinical experience with the delivery of thawed and washed autologous blood cells, with an automated closed fluid management device: CytoMate.

BACKGROUND: Washing out of thawed autologous grafts, before reinfusion in poor-prognosis cancer patients who undergo high-dose chemotherapy, is desirable. The procedure allows for the reduction of infused dimethyl sulfoxide (DMSO) quantities and the performance of biologic controls on the infused cell product. STUDY DESIGN AND METHODS: Three-hundred four patients were treated with intensified chemotherapy and autologous transplantation at a single institution. Fifty-four of them received washed cell products, because three or more bags were to be reinfused. The recently available, closed, automated, and current good manufacturing practice-compliant device (CytoMate, Baxter Oncology) was used for this purpose. RESULTS: The performances of the device were similar to previously reported results, with greater than 75 percent CD34+ cell recovery. Neutrophil and platelet (PLT) recoveries were similar in the group of patients receiving washed cells and in the group of patients for whom cell products were extemporaneously thawed at the bedside. Adverse events that are typically reported after DMSO infusion were significantly less frequent and less severe in patients who received washed cells. Finally, the nurse staff on the transplant ward reported a decreased workload and more satisfactory procedure when infusing washed cell products. CONCLUSION: The CytoMate device allows for a significant reduction in DMSO infusion, with a diminished frequency and severity of immediate side effects and does not compromise neutrophil or PLT engraftment.

Adult↗
PubMed2004

DNAM-1 and PVR regulate monocyte migration through endothelial junctions.

DNAX accessory molecule 1 (DNAM-1; CD226) is a transmembrane glycoprotein involved in T cell and natural killer (NK) cell cytotoxicity. We demonstrated recently that DNAM-1 triggers NK cell-mediated killing of tumor cells upon engagement by its two ligands, poliovirus receptor (PVR; CD155) and Nectin-2 (CD112). In the present paper, we show that PVR and Nectin-2 are expressed at cell junctions on primary vascular endothelial cells. Moreover, the specific binding of a soluble DNAM-1-Fc molecule was detected at endothelial junctions. This binding was almost completely abrogated by anti-PVR monoclonal antibodies (mAbs), but not modified by anti-Nectin-2 mAbs, which demonstrates that PVR is the major DNAM-1 ligand on endothelial cells. Because DNAM-1 is highly expressed on leukocytes, we investigated the role of the DNAM-1-PVR interaction during the monocyte transendothelial migration process. In vitro, both anti-DNAM-1 and anti-PVR mAbs strongly blocked the transmigration of monocytes through the endothelium. Moreover, after anti-DNAM-1 or anti-PVR mAb treatment, monocytes were arrested at the apical surface of the endothelium over intercellular junctions, which strongly suggests that the DNAM-1-PVR interaction occurs during the diapedesis step. Altogether, our results demonstrate that DNAM-1 regulates monocyte extravasation via its interaction with PVR expressed at endothelial junctions on normal cells.

Antigens, Differentiation, T-Lymphocyte↗
PubMed2004

CD8+ T cell dose affects development of acute graft-vs-host disease following reduced-intensity conditioning allogeneic peripheral blood stem cell transplantation.

OBJECTIVE: Acute graft-vs-host disease (aGVHD) remains an important cause of morbidity after reduced-intensity conditioning (RIC) allogeneic transplantation (allo-SCT). It has been shown that antithymocyte globulin (ATG) dose infused during RIC is a major determinant for the likelihood of developing aGVHD. The ATG modulation on aGVHD is likely related to in vivo T-cell depletion. PATIENTS AND METHODS: We therefore investigated the relationship between the cellular composition of the allograft and clinical outcome in 57 patients who received allogeneic peripheral blood stem cells from HLA-identical siblings following an ATG-based RIC. RESULTS: In a multivariate analysis, the CD8+ T cell dose infused was the only parameter associated with the risk of aGVHD (p=0.031; RR=1.96; 95% CI, 1.1-3.6). When looking at the extremes, patients experiencing grade III-IV aGVHD received a median of 143 x 10(6)/kg CD8+ T cells, while patients without aGVHD received a median of 96 x 10(6)/kg CD8+ T cells (p=0.021). None of the different cell subtypes contained in the allograft was associated with a significant probability of developing chronic GVHD. Patients with grade II aGVHD who received an intermediate dose of CD8+ T cells (median, 111 x 10(6)/kg) had a significantly better overall survival in comparison to patients with grade 0-I or grade III-IV aGVHD (p=0.009). CONCLUSION: In comparison to myeloablative allo-SCT, these results demonstrate that a cautious monitoring of the number of cells infused, at least in the context of ATG-based RIC, may represent an important predictive indicator of early transplant-related events and outcome after RIC allo-SCT.

Acute Disease↗
PubMed2004

Restriction of transgene expression to the B-lymphoid progeny of human lentivirally transduced CD34+ cells.

Development of gene transfer strategies will necessitate improved efficiency and control of transduction and transgene expression. We here provide evidence that targeting expression of the GFP reporter gene to the B-lymphoid progeny of genetically modified human hematopoietic progenitor cells can be achieved through the insertion of regulatory sequences from the human CD19 gene promoter into a lentiviral vector. Based on a bioinformatics approach, three human CD19-derived sequences were designed and inserted into a self-inactivated lentiviral vector backbone upstream of the GFP gene: S.CD19 (230 bp), M.CD19 (464 bp), and L.CD19 (1274 bp). These new lentiviral vectors efficiently transduced cord blood CD34(+) cells. The M.CD19 and especially L.CD19 sequences preferentially targeted GFP expression to in vitro and in vivo differentiated CD19(+) progeny; moreover, transgene expression was detected from the CD34(+) pro/pre-B cell to the mature peripheral IgM(+) B cell stage. In contrast, GFP expression was weak or absent in primary T-lymphoid and uncommitted progenitor cells or in erythroid, natural killer, or myeloid differentiated cells. Such B-lineage-specific lentiviral vectors may be useful for correcting inherited disorders that affect B-lymphoid cells or for deciphering the transcriptional program that controls B cell commitment and differentiation.

Animals↗
PubMed2003

Reduced-intensity preparative regimen and allogeneic stem cell transplantation for advanced solid tumors.

In this prospective multicenter program, we investigated allogeneic stem cell transplantation (ASCT) from HLA-identical siblings following reduced-intensity conditioning (RIC) regimen for patients with refractory metastatic solid tumors (STs). Fifty-seven patients, of whom 39 had a progressive disease (PD) at time of ASCT, received an RIC ASCT combining fludarabine, antithymocyte globulin (ATG), and busulfan. Patients were analyzed in terms of engraftment, transplant-related mortality (TRM), disease response, and outcome. In this setting, RIC was associated with rapid engraftment and low overall TRM (9% [95% confidence interval (CI), 1%-16%]). The cumulative incidence of objective responses (ORs) reached 14% (95% CI, 6%-30%) with this being significantly higher in patients without PD (44% [95% CI, 21%-67%] versus 0; P <.0001) at time of ASCT. Achievement of OR translated into a significantly better overall survival (OS). In multivariate analysis, OS was significantly influenced by disease status at time of ASCT (odds ratio, 4.88; P <.001) and chronic graft-versus-host disease (GVHD) occurrence (odds ratio, 2.86; P <.01). Overall, these results showed that OR can occur after RIC ASCT for resistant ST with a relatively low TRM and potential benefit especially in patients with slowly progressive disease. Further studies are warranted in patients with less advanced ST.

Acute Disease↗
PubMed2003

Graft-versus-host disease following allogeneic transplantation from HLA-identical sibling with antithymocyte globulin-based reduced-intensity preparative regimen.

Reduced-intensity conditioning (RIC) regimens are increasingly used for allogeneic stem cell transplantation (allo-SCT). RIC has been shown to allow engraftment with minimal early transplantation-related mortality (TRM). However, in the context of RIC, predictive factors for acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) and their effect on outcome remain unknown. In this report, we analyzed the outcome of 101 high-risk patients (70 hematologic and 31 nonhematologic malignancies) who received an HLA-identical sibling allo-SCT after RIC, including fludarabine, busulfan, and antithymocyte globulin (ATG). The cumulative incidence of grade II-IV aGVHD was 36% (95% confidence interval [CI], 27%-45%), whereas the cumulative incidence of cGVHD at 2 years was 43% (95% CI, 33%-53%). In multivariate analysis, the incidence of aGVHD was significantly associated with the ATG dose infused during conditioning (P =.0005), whereas peripheral blood as stem cell source was the only predictive factor for the development of cGVHD (P =.0007). The 1-year cumulative incidences of disease progression or relapse in patients with (n = 69) and without (n = 31) GVHD (whatever its form or grade) were 30% (95% CI, 19%-41%) and 55% (95% CI, 37%-72%), respectively (P =.02), suggesting that a potent graft-versus-tumor (GVT) effect can be achieved in high-risk patients following RIC. Moreover, the GVT effect was closely associated with GVHD without an increased risk of TRM (cumulative incidence of TRM, 18% [95% CI, 10%-25%]). Collectively, these results provide a framework for the refinement of RIC approaches designed to enhance the GVT effect with an acceptable risk of GVHD.

Acute Disease↗
PubMed2003

Bone marrow as stem cell source for allogeneic HLA-identical sibling transplantation following reduced-intensity preparative regimen.

OBJECTIVE: Reduced-intensity conditioning regimens (RIC) and peripheral blood stem cells (PBSC) are increasingly used for allogeneic stem cell transplantation (allo-BMT). RIC has been shown to allow engraftment with minimal early transplant-related mortality (TRM). However, in the context of RIC, the use of bone marrow (BM) as stem cell source is still little evaluated. PATIENTS AND METHODS: In this report, we analyzed the outcome of 32 high-risk patients with hematological malignancies who received an HLA-identical sibling allo-BMT after RIC including fludarabine, busulfan, and anti-thymocyte globulin (ATG). RESULTS: Sustained neutrophil and platelet recovery occurred at a median of 13 days (range, 10-19) and 17 days (range, 0-45) respectively. Early and durable full donor chimerism could be established as soon as the first month after allo-BMT. Also, a sustained and early CD8(+) T-cell recovery was observed, but the CD4(+) T-cell compartment remained profoundly low. The cumulative incidences of grade II-IV acute GVHD and chronic GVHD were 26% (95% CI, 11-41%) and 31% (95% CI, 15-47%) respectively. The overall cumulative incidence of TRM was 28% (95% CI, 12-44%) occurring mainly in patients aged over 50. In this setting, GVHD showed a protective effect on disease progression or relapse with better progression-free survival for patients with GVHD as compared to patients without GVHD (p=0.03). CONCLUSIONS: Collectively, these results confirm that the use of BM grafts for RIC is feasible with durable donor engraftment and no detrimental GVHD.

Adult↗
PubMed2003

Overexpression of dominant-negative Ikaros 6 protein is restricted to a subset of B common adult acute lymphoblastic leukemias that express high levels of the CD34 antigen.

Ikaros is a critical regulator of hematopoiesis. Its effects result in part from the balance between the isoforms that are produced by differential splicing of the pre-mRNA. Short isoforms that lack the DNA-binding domain act as dominant negatives by binding long isoforms through the C-terminal zinc-finger domain, which allows for the homo- or heterodimerization of the proteins. There are a number of evidences that different subsets of murine hematopoietic progenitors - as defined by phenotype - have different patterns of Ikaros expression. Forced expression of short isoforms (Ik5, Ik6 or Ik7) in murine or human hematopoietic progenitors alters the differentiation capacities of these cells. Human leukemias provide additional information: because of the blockade in differentiation, leukemias represent an equivalent of a particular stage of human hematopoietic hierarchy. We and others have shown that human acute leukemias are heterogeneous for the pattern of Ikaros isoform expression. The present study focused on adult de novo B ALLs and the Ikaros 6 isoform. ProB (BI, n=3), common B (BII, n=15) and preB (BIII, n=3) ALL were identified by their phenotype. RT-PCR and Western blot analyses of blast cell protein lysates suggest that approximately 50% of BII leukemias overexpress Ikaros 6 RNA and protein. Comparison of BII cells with high or normal levels of Ik6 shows a higher level of expression for the membrane stem cell antigen CD34 in the former, as detected with flow cytometry and confirmed with DNA arrays.

Adolescent↗
PubMed2002

Transient detection of beta-galactosidase activity in hematopoietic cells, following reinjection of retrovirally marked autologous blood progenitors in patients with breast or ovarian cancer receiving high-dose chemotherapy.

OBJECTIVE: The aim of this report is to demonstrate the feasibility and safety of genetically modifying autologous human blood CD34(+) cells in vitro, with a retroviral vector that encodes a marker gene. The fate of genetically modified cells and their progeny was followed in vivo, after reinfusion in patients treated with high-dose chemotherapy for poor-prognosis breast or ovarian carcinomas. PATIENTS AND METHODS: Six patients received genetically modified autologous peripheral blood progenitors, together with unmanipulated aphereses, following high-dose chemotherapy. CD34(+) cells were immunoselected from aphereses, and retrovirally transduced by coculture with the retroviral vector producing cell line, to express a nuclear localized version of E. coli beta-galactosidase, encoded by a defective Moloney-murine leukemia virus-derived retroviral vector. Cells were reinfused to the patients after myeloablation, without prior ex vivo selection. RESULTS: Five out of six patients showed the transient presence of low numbers of beta-galactosidase(+) cells, as detected with an immunocytochemical assay, in the peripheral blood, during the first month following infusion. One patient had beta-galactosidase(+) clonogenic progenitors in her marrow at two months after transplantation, including HPP-CFC; intriguingly, this patient had the lowest percentage of X-gal(+) cells in her graft. Patients experienced side effects that are often observed after high-dose chemotherapy. CONCLUSIONS: Feasibility and safety of genetic modification of human hematopoietic stem and progenitor cells are demonstrated by this study. Ex vivo or in vivo selection is not mandatory, even in clinical situations where transduced cells have no survival advantage over wild-type cells; however, significant improvements in gene transfer technology are needed to achieve potentially useful levels of expression in such clinical situations.

Aged↗
PubMed2002

Ikaros gene expression and leukemia.

The Ikaros (Ik) protein, or LyF1, was initially described as a protein binding to regulatory sequences of a number of genes expressed in murine lymphoid cells. Ikaros is a critical regulator of normal hematopoietic stem cell differentiation, as evidenced by dramatic defects in the lymphoid compartments, in homozygous animals with gene inactivation. Because differential splicing produces multiple isoforms with potentially different functions, Ikaros provides a unique model to study how post-transcriptional mechanisms may be involved in neoplastic processes. Indeed, several groups including ours have underlined evidences that expression of different Ikaros isoforms vary among different types of leukemias. The predominance of short isoforms in certain subsets is intriguing. Here, additional observations reinforced the hypothesis that Ikaros expression may be deregulated in human leukemias. Whether this is a cause or a consequence of the leukemic process remains speculative. Other human diseases however, provide examples of abnormal post-transcriptional regulations that have been further characterized.

Alternative Splicing↗
PubMedDate not supplied

[Immunotherapy of acute myeloid leukemias: development of vaccines and cell therapy approaches].

Prognosis of acute myeloblastic leukemias (AML) remains with relapse, at a time when progress in chemotherapy regimens have increased the rate of complete remission, and improved biological tools have helped in defining diagnostic and prognostic criteria for this heterogeneous group of diseases. Allogeneic stem cell transplantation offers an example of a situation in which various immune effectors can contribute to the eradication of residual leukemic cells. However, use of allogeneic transplantation is restricted to a minority of patients. Thus, the development of immunotherapy strategies that could be used for all patients, appears highly desirable. Progress in fundamental immunology, and a better understanding of the role of the immune system in the physiopathology of leukemias now open new avenues to design innovative therapies. We here review recently published observations in this field, and propose new vaccine programs that use autologous AML blasts differentiated into dendritic cells.

Acute Disease↗