INTERET DE L'IMMUNOPHENOTYPAGE DANS L'EVALUATION DE LA MALADIE RESIDUELLE AU COURS DES LEUCEMIES AIGUES LYMPHOBLASTIQUES DE LA LIGNEE B CHEZ L'ENFANT

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Etude des progéniteurs hématopoïétiques CD34 positif après traitement d'induction des LAL de la lignée B de l'enfant

AIX-MARSEILLE2-BU Pharmacie (130552105) / SudocSudocFranceF

Apport de l'automatisation dans l'étude de l'érythropoïèse fonctionnelle

AIX-MARSEILLE2-BU Pharmacie (130552105) / SudocSudocFranceF

Cellules F après greffes de cellules souches hématopoïétiques de sang placentaire (à propos de 11 cas)

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Four- and five-color flow cytometry analysis of leukocyte differentiation pathways in normal bone marrow: a reference document based on a systematic approach by the GTLLF and GEIL.

International audienceBACKGROUND: The development of multiparameter flow cytometry (FCM) and increasingly sophisticated analysis software has considerably improved the exploration of hematological disorders. These tools have been widely applied in leukaemias, lymphomas, and myelodysplasias, yet with very heterogeneous approaches. Consequently, there is no extensive reference document reporting on the characteristics of normal human bone marrow (BM) in multiparameter FCM. Here, we report a reference analysis procedure using relevant antibody combinations in normal human BM. METHODS: A first panel of 23 antibodies, constructed after literature review, was tested in four-color combinations (including CD45 in each) on 30 samples of BM. After evaluation of the data, a second set of 22 antibodies was further applied to another 35 BM samples. All list-modes from the 65 bone marrow samples were reviewed collectively. A systematised protocol for data analysis was established including biparametric representations and color codes for the three major lineages and undifferentiated cells. RESULTS: This strategy has allowed to obtain a reference atlas of relevant patterns of differentiation antigens expression in normal human BM that is available within the European LeukemiaNet. This manuscript describes how this atlas was constructed. CONCLUSIONS: Both the strategy and atlas could prove very useful as a reference of normality, for the determination of leukemia-associated immunophenotypic patterns, analysis of myelodysplasia and, ultimately, investigation of minimal residual disease in the BM

Evaluation of paroxysmal nocturnal hemoglobinuria screening by flow cytometry through multicentric interlaboratory comparison in four countries.

OBJECTIVES: Paroxysmal nocturnal hemoglobinuria (PNH) is currently diagnosed by flow cytometry; although highly sensitive, its interpretation and reporting appear as critical as its technique. Thus, we developed a quality control scheme for the French-speaking region based on the international recommendations for PNH screening. METHODS: After a topical workshop, we proposed a 1-year, two-step survey program to any volunteering French-speaking clinical laboratory. The first survey consisted of sending raw data files to evaluate gating and the interpretation strategy of each center. The second stipulated sending fresh whole-blood samples to evaluate the whole process and its practice. RESULTS: Forty-nine participants from voluntary centers returned results for each of the two successive surveys. On virtual survey, 27% reported false-positive PNH created by immature granulocytes, whereas the minor PNH clone was not detected by 9%. On fresh survey, 63% of centers used at least the same six-color combination (CD24, CD14, CD33, CD15, CD45, and fluorescent aerolysin), and nearly 70% of participants were able to perform a sensitivity test less than 0.1% on neutrophils. All participants detected the major PNH clone, yet 16% returned false-positive results for the non-PNH clone case. CONCLUSIONS: We succeeded in rallying numerous French-speaking clinical laboratories for both surveys and in harmonizing the technical practice by highlighting common pitfalls

MYC fails to efficiently shape malignant transformation in T-cell acute lymphoblastic leukemia.

International audienceMYC is a potent oncogene involved in ∼70% of human cancers, inducing tumorigenesis with high penetrance and short latency in experimental transgenic models. Accordingly, MYC is recognized as a major driver of T-cell acute lymphoblastic leukemia (T-ALL) in human and zebrafish/mouse models, and uncovering the context by which MYC-mediated malignant transformation initiates and develops remains a considerable challenge. Because MYC is a very complex oncogene, highly dependent on the microenvironment and cell-intrinsic context, we generated transgenic mice (tgMyc(spo)) in which ectopic Myc activation occurs sporadically (<10(-6) thymocytes) within otherwise normal thymic environment, thereby mimicking the unicellular context in which oncogenic alterations initiate human tumors. We show that while Myc(+) clones in tgMyc(spo) mice develop and initially proliferate in thymus and the periphery, no tumor or clonal expansion progress in aging mice (n = 130), suggesting an unexpectedly low ability of Myc to initiate efficient tumorigenesis. Furthermore, to determine the relevance of this observation in human pathogenesis we analyzed a human T-ALL case at diagnosis and relapse using the molecular stigmata of V(D)J recombination as markers of malignant progression; we similarly demonstrate that despite the occurrence of TAL1 and MYC translocations in early thymocyte ontogeny, subsequent oncogenic alterations were required to drive oncogenesis. Altogether, our data suggest that although central to T-ALL, MYC overexpression per se is inefficient in triggering the cascade of events leading to malignant transformation

Mutual benefits of B-ALL and HLDA/HCDM HLDA 9th Barcelona 2010.

International audienceThe B-cell panel of the ninth HLDA was applied in a multicentre fashion to cryopreserved cells from 46 patients with acute lymphoblastic leukemia. The reagents were aliquoted and shipped to volunteer participants from the French Groupe d'Etude Immunologique des Leucémies (GEIL). All samples were tested in flow cytometry, and the results collected as of the strength of labeling of the leukemic clone as negative, weak or strong. Among the 64 antibodies tested, the strongest and most frequent staining was observed for CD305 (LAIR), CD229 (Ly9), CD200 (OX-2) and, to a lesser extent, CD361 (EVI2b). Details of the observations, and information about the molecules tested are provided in the manuscript as well as a summary table

Le ciel à découvert

Un tour d’horizon de l’astrophysique contemporaine. Une synthèse fondamentale, sans précédent, ouverte à tous. Les plus récentes découvertes présentées par les meilleurs spécialistes. Le Soleil et l’ensemble du système planétaire. Les étoiles et le milieu interstellaire. Les galaxies et les grandes structures de l’Univers. La cosmologie... Où en est l’astronomie, aujourd’hui ? Quelles révolutions a-t-elle traversées ? Qu’en est-il de la Terre ? De la vie, ailleurs, dans l’Univers ? De la recherche d’exoplanètes ? Des moyens les plus récents et les moins conventionnels d’observer le ciel ? Qu’en sera-t-il, demain, des savants, de leurs laboratoires, de leurs instruments, de leurs méthodes, de leurs découvertes ? Voici, enfin, un panorama complet et inédit sur la façon dont les astrophysiciens voient et comprennent ce Monde qui est le nôtre