M C Léglise

Centre Hospitalier Universitaire de Brest, Brest, Brittany, France

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Publications (16)38.68 Total impact

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    ABSTRACT: Donor leukocyte infusions (DLI) have turned out to be an efficient way to re-establish complete remission (CR) in chronic myeloid leukemia (CML) patients relapsing after allogeneic bone marrow transplantation (BMT). In these patients, absence of PCR bcr-abl fusion transcripts confirmed the potency of donor leukocytes to induce molecular response in relapsed CML. This ensured sustained remission and long-term survival. In this study, the capacity of DLI to induce molecular remission in acute leukemia relapse after BMT was analyzed. The results showed that following DLI, leukemic cell eradication gradually occurred over a prolonged time period. The time to complete disappearance of the molecular marker of the disease was 30 weeks in RT-PCR analysis. A sustained and persistent elimination of an AML1/ETO-positive leukemic clone in an AML-M2 patient was observed. In contrast, an AML-M5 with t(11;19) and an E2A/PBX1-positive ALL achieving cytogenetic and molecular bone marrow CR developed following DLI unusual sites of extramedullary leukemia relapse, despite continued bone marrow remission. This study adds further proof of the benefit of donor cell therapy in acute leukemia but shows that complete leukemic cell eradication appears to require a critical interval in order to establish effective immune responses at all sites where leukemic cells persist.
    Leukemia 12/1998; 12(11):1676-81. · 10.16 Impact Factor
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    ABSTRACT: We have studied, by fluorescence in situ hydridization (FISH), chromosomes 5 and 7 in a series of 11 cases with 5q deletion, as sole anomaly (four cases), or in association with 7q deletion (seven cases), in MDS/AML patients. We found that, in some cases, a part of the so-called 'lost' chromosome 5 and 7 material, was actually translocated. These translocations may be either end-arm or whole-arm, as well as small insertions. Chromosomes 5 or 7 may be broken in more than two segments, defining 'fragmentation', giving rise to marker chromosomes. FISH allowed the identification of small material insertion, which is totally unidentified by classical cytogenetics. Chromosome 5 and 7 translocations occur irrespectively of the 'de novo' or 'secondary' type of myelodysplastic syndrome (MDS)/acute myeloid leukaemia (AML) patients.
    Leukemia Research 05/1998; 22(4):303-12. · 2.76 Impact Factor
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    ABSTRACT: The effects of chronic exposure to phytosanitary products are difficult to determine because of their use in combination with other products and their variety of formulations containing additives or contaminants. In order to evaluate, at the cellular level, the risk of myelosuppressive effects caused by two widely used herbicides, atrazine and dinoterb, we performed in vitro assays on human granulo-monocytic progenitor-cells (CFU-GM) and also granulomonocytic expansion in liquid media. Both of these techniques were carried out in the presence of each molecule. Seven stable environmental metabolites of atrazine were studied using the above techniques in addition to supernatants of rat hepatocytes preincubated with atrazine and dinoterb for 24 hr. Parent atrazine and dinoterb showed similar moderate-direct toxicity on CFU-GM. In cells grown in liquid media for a period longer than 14 days, dinoterb toxicity appeared delayed but increased when compared with atrazine. 2-chloro-diamino-atrazine was found to be as toxic as atrazine on CFU-GM. Supernatants of rat hepatocyte preincubated for 24 hr with dinoterb exhibited a 150-fold increase in toxicity compared with the parent molecule, while toxicity remained unchanged for atrazine. This phenomenon was directly correlated to toxicity on rat hepatocytes. The present study will be useful in defining tissue-specific toxicities of phytosanitary products, including environmental or biotransformed metabolites.
    Toxicology in Vitro 04/1998; 12(2):183-90. · 2.65 Impact Factor
  • Toxicology Letters - TOXICOL LETT. 01/1998; 95:110-110.
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    ABSTRACT: We report four cases of polysomy 8 (one tetrasomy and three pentasomies) observed in acute monocytic leukemia (FAB M4 and M5). Three of them showed a rearrangement of 11q23 identified by conventional cytogenetic analysis and/or chromosome painting. Our cases as well as a review of the literature, suggest that polysomy 8 is preferentially associated with monocytic differentiation (24/31). These polysomies have been observed in 21 de novo leukemias and in 10 secondary hematological disorders. A 11q23 rearrangement has been detected in 9 out of 32 patients, by conventional cytogenetic techniques in 7 and by FISH in 2. We suggest that these cases should be analysed by FISH and molecular studies in order to detect a rearrangement of MLL/11q23. Monocytic differentiation is often associated with a change of the MLL gene and the polysomy 8 might be a particular clonal evolution secondary to 11q23 abnormality.
    Leukemia and Lymphoma 10/1997; 27(1-2):127-35. · 2.61 Impact Factor
  • Leukemia and Lymphoma 05/1996; 21(3-4):187-99. · 2.61 Impact Factor
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    ABSTRACT: The erythromyeloid cell line, K562, the most sensitive target in human natural killer (NK) cell mediated cytotoxicity, is derived from a chronic myeloid leukemia (CML) patient and expresses the characteristic reciprocal translocation t(9;22). The resulting BCR-ABL fusion protein has been shown to mediate the unusual resistance of K562, and other BCR-ABL expressing lines, to apoptosis induced by a variety of agents (irradiation, UV light, cytotoxic drugs). Here we show that human NK and lymphokine-activated killer (LAK) cells, when tested at low effector to target ratio, can readily induce apoptotic death in K562 cells. This was accompanied with classical DNA oligonucleosomal fragmentation, an unexpected finding given the reported lack of such fragmentation when apoptosis is induced in K562 by chemical agents, after downregulation of BCR-ABL. Apoptosis was assessed by several means: morphological studies, 125I-DNA versus 51Cr release, DNA agarose gel electrophoresis, and results were always concordant, with a delayed kinetics for DNA oligonucleosomal fragmentation. Similar data were obtained with a pluripotent human hematopoietic cell line, UT-7, infected with a defective amphotropic p210 BCR-ABL retrovirus. The BCR-ABL expressing subclone UT-7/9, while being no longer sensitive to cytotoxic drugs or to tumor necrosis factor, a lytic mediator to which UT-7 cells are sensitive, underwent apoptotic death when exposed to LAK effector cells to the same degree as the parental UT-7 line. With these targets, DNA oligonucleosomal fragmentation occurred concomitantly with isotope release. Results obtained with several inhibitors of exocytosis strongly suggest that cytotoxic granules mediate NK and LAK cell-induced apoptotic death. In conclusion, NK and LAK cell-induced apoptotic signals, unlike those activated by chemotherapeutic agents, are unaffected by the antiapoptotic action of BCR-ABL. This unique property may support the observed curative effect of allogeneic bone marrow transplantation in CML.
    Blood 03/1996; 87(3):1113-22. · 9.78 Impact Factor
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    ABSTRACT: A cellular model of hematopoiesis which would be more convenient than bone marrow (BM) progenitors and directly relevant to human pathology is needed in order to investigate xenobiotic toxicity. Human umbilical cord blood (HCB), previously shown to be able to repopulate BM, provides a powerful in vitro model of normal human hematopoiesis. In order to validate the use of normal HCB progenitors as targets for dose-related myelosuppression, we used clonogenic assays and expansion in a liquid culture of progenitor-enriched cell suspensions from HCB. A series of 8 reference molecules, doxorubicin, cytosine-arabinoside, 5-fluorouracil, 3'-azido-3'-deoxythymidine, acetylsalicylic acid, sodium valproate and two cephalosporin antibiotics, were tested. In vitro 50% inhibition concentrations (IC50) were compared to those observed or reported with BM progenitors, and to the values of plasma concentrations from treated patients. HCB progenitors as in vitro targets for cytotoxic molecules were easy to access and handle, and their use was sensitive, specific and reproducible. They gave results similar to BM progenitors and allowed a qualitative approach to cellular metabolism and toxicity using morphological, flow cytometric and chromatographic methods.
    Cell Biology and Toxicology 03/1996; 12(1):39-53. · 2.34 Impact Factor
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    ABSTRACT: The decisions of health authorities concerning adverse effects of drugs are usually notified following clinical observations, but are rarely associated to experimental data. The haematopoietic tissue is one of the most sensitive to these effects. In order to anticipate and to explain adverse effects, it becomes necessary to carry out in vitro assays on normal human haematopoietic progenitors. We had the opportunity to use human cord blood progenitors which are able to repopulate allogeneic aplastic bone marrow. Many advantages are associated with this model: numerous samples, non-invasive, absence of species bias, possibilities of mechanistic approach. The clonogenic potential of progenitors in soft agar, as well as their ability to expand in liquid medium after stimulation with specific growth factors, have been used. Evidence of dose-related toxicity by inhibition of colony formation or proliferation was analysed in the presence of reference molecules. Results were reproducible despite an intrinsic variability of progenitor density between samples. They were comparable to assays on bone marrow progenitors reported by us and others. Comparison of toxicity thresholds with plasma therapeutic ranges showed the potential risk for some molecules tested.
    Thérapie 01/1996; 51(5):489-99. · 0.37 Impact Factor
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    ABSTRACT: Bone marrow colony forming unit-granulocyte macrophage (CFU-GM) cultures of 14 patients after neutrophil recovery from drug-induced agranulocytosis (median 12 weeks) were performed in the presence of 20 different drugs and/or acute-phase serum (APS) obtained during agranulocytosis. In 10 cases, drugs involved in agranulocytosis in vivo caused a significant inhibition of CFU-GM growth in vitro in comparison with normal cultures without drug. Three types of direct toxicity are suggested: (i) a decrease in the rate of mitosis; (ii) a destruction of cells (cytotoxic effect); or (iii) a blockage in progenitor mitosis (cytostatic effect). A humoral mechanism was suggested in 1 case because of enhanced inhibition with APS. In 4 cases no effect of the suspected drug could be detected by in vitro studies, but all hypotheses have not been tested in these cases, particularly the possible role of APS and other substances.
    Drug Safety 01/1994; 9(6):463-9. · 2.62 Impact Factor
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    ABSTRACT: The nature of translocation t(4;11) acute leukemia cells has been widely discussed over the past few years. Many authors report their phenotypic heterogeneity, ranging from apparently common acute lymphoblastic leukemia antigen-positive to monoblastic leukemia, through "promiscuous" phenotype. We studied in vitro phenotypic modulation of three typical cases after induction by 12-O-tetradecanoyl phorbol 13 acetate. The initial phenotype was different in each case, but all of them exhibited changes in morphologic shape, cytochemistry, and immunophenotype; common features appeared after induction by 12-O-tetradecanoyl phorbol 13 acetate, including esterase activity, expression of CD-9, CD-15, and CD-18 surface antigens, and monocyte/macrophage morphology. In all cases a B-associated surface antigen, CD-19, persisted. During clinical evolution, some previously reported cases have shown a karyotypic and phenotypic transformation. In one of our cases this phenomenon correlated with in vitro phenotypic modulation of initial blast population. Furthermore, clinical relapses and in vitro modulation always seem to evolve toward a more "mature" phenotype. Those results support the "promiscuous lineage" hypothesis, and point out the usefulness of in vitro studies to express the myeloid potential of this category of acute leukemia, which can be regarded as a model of early hematopoietic differentiation.
    Archives of pathology & laboratory medicine 03/1989; 113(2):164-8. · 2.78 Impact Factor
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    ABSTRACT: The morphological, ultrastructural, and immunological characteristics of two cases of acute leukemia with t(4;11) (q21;q23) were studied. The blasts from both cases were initially classified as L1 lymphoblasts. Ultrastructural examination indicated a heterogenous blast population in both cases, with some regular lymphoblast-like cells, and others exhibiting nuclear irregularity, small bundles of microfilaments, or large inclusions. In one case at diagnosis, fresh cells expressed B-associated and a myeloid antigen (B4 and 1G10). At the second relapse, the cells from this patient expressed another myeloid-associated antigen, LFA1 molecule, recognized by the monoclonal antibody M232 (CD18). At the end of clinical evolution, a further myeloid antigen was expressed (OKM1), while 8% peroxidase were noted. The other case was studied at diagnosis only and did not express any myeloid marker but expressed the B-associated B4 antigen. Furthermore, the case that exhibited a phenotypic transformation, was noted to show a chromosomal clonal evolution not described so far in other reported cases of t(4;11) acute leukemia. A dual lymphoid-myeloid nature of t(4;11) acute leukemia has been widely discussed. One of the cases reported here supports this hypothesis while the other does not. We would like to underline the possibility of heterogeneity of a case at presentation and transformation to a myeloid phenotype through clonal evolution.
    Nouvelle revue française d'hématologie 02/1987; 29(5):295-301.
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    ABSTRACT: 42 patients with acute leukaemia, treated with cytotoxic drugs, have been evaluated retrospectively: --group I: 11 patients received packed red blood cells and platelets from single donors; --group II: 6 patients received packed red blood cells and platelets from multiple donors; --group III: 25 patients received packed red blood cells and platelets from single or multiple donors and granulocytes transfusions. There was no difference in age, sex, time of follow up, number of transfusions, in the three groups. The rate of alloimmunization defined as lymphocytotoxicity against more than 20% of a panel of 24 lymphocytes, was 33% (36% group I--33% group II--32% group III). This study shows that platelets from single donors are of no use in preventing or delaying alloimmunization. On the other hand, their major interest is to provide alloimmunized patients with compatible platelets.
    Revue Francaise de Transfusion et Immuno-hematologie 03/1984; 27(1):35-44.
  • M C Leglise, J Briere, J F Abgrall, D Hurez
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    ABSTRACT: We report on a patient with a bone marrow plasmacell infiltration, since this case displays some outstanding clinical and laboratory features: the presence of massive splenomegaly and the absence of bone lesions; the cytoplasmic heavy chain type mu, without any light chain detectable by immunofluorescence (IF); the non secretory feature of this plasma cell proliferation. The position of such an entity within the spectrum of B-lymphoproliferative disorders, from mu heavy chain disease to non secretory IgM myeloma, is discussed.
    Nouvelle revue française d'hématologie 02/1983; 25(2):103-6.
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    ABSTRACT: 42 patients with acute leukaemia, treated with cytotoxic drugs, have been evaluated retrospectively:-group I: 11 patients received packed red blood cells and platelets from single donors;-group II: 6 patients received packed red blood cells and platelets from multiple donors;-group III: 25 patients received packed red blood cells and platelets from single or multiple donors and granulocytes transfusions.There was no difference in age, sex, time of follow up, number of transfusions, in the three groups.The rate of alloimmunisation defined as lymphocytotoxicity against more than 20% of a panel of 24 lymphocytes, was 33% (36% group I—33% group II—32% group III).This study shows that platelets from single donors are of no use in preventing or delaying alloimmunisation. On the other hand, their major interest is to provide alloimmunised patients with compatible platelets.
    Revue Française de Transfusion et Immuno-hématologie.
  • La Ricerca in Clinica e in Laboratorio 14(3):313-8.