ALBERT

Beschreibung: Alain Ducellier, né à Paris en 1934 a fait ses études aux lycées Jacques-Decour et Henri IV puis a soutenu en Sorbonne, dès 1957, un D.E.S. d’Histoire byzantine sous la direction de Rodolphe Guilland. Agrégé d’Histoire en 1959, il a entrepris, sous la direction de Paul Lemerle, une thèse d’Etat consacrée à La Façade maritime de l’Albanie au Moyen Âge. Durazzo et Valona du xe au xve siècle, soutenue en Sorbonne en 1971. Professeur au lycée de Reims puis à Janson de Sailly à Paris, il devient assistant à la faculté de Tunis de 1963 à 1967, puis maître-assistant à l’université de Toulouse où il est ensuite élu maître de conférences en 1971 et professeur en 1973. De 1981 à 1985 il est membre du jury de l’agrégation d’histoire. Membre du L.A. 186, Histoire et Civilisation de Byzance (Paris, Collège de France) et du laboratoire Diasporas (Université de Toulouse-Le Mirail). Cette carrière a déterminé la nature et l’évolution de son enseignement comme celle de ses recherches : l’assise majeure a toujours été l’histoire de l’Empire byzantin, dont il a souvent privilégié les périphéries, comme en témoignent ses nombreux travaux relatifs à l’Albanie médiévale et aux Balkans en général, mais aussi les relations avec l’environnement musulman auquel il a longtemps consacré une partie de son enseignement à Tunis puis à Toulouse.

Beschreibung: Journal of Atmospheric and Oceanic Technology, Ahead of Print. 〈br/〉

Beschreibung: ABSTRACT The use of shRNAmir to down-regulate the expression of genes of interest is a powerful tool for studying gene function during early chick development. However, due to the limitations of electroporation-mediated transgenesis, the down-regulation of genes expressed at late stages of development in specific tissues is difficult to perform. By combining electroporation of a doxycycline-inducible, miR30-based shRNA plasmid with the Tol2 genomic integration system, we are now able to down-regulate the expression of any gene of interest at defined stage of chicken development. © 2013 Wiley Periodicals, Inc.

Beschreibung: Key Points Matching for MICA significantly reduces the incidence of acute and chronic GVHD in otherwise HLA 10/10-matched unrelated-donor HCT. Our results formally define MICA as a novel major histocompatibility complex-encoded human transplantation antigen.

Beschreibung: Abstract 4188 Cumulative evidence indicates that MYC, one of the major downstream effectors of NOTCH1, is a critical component of T-cell acute lymphoblastic leukemia (T-ALL) oncogenesis and a potential candidate for targeted therapy. However, MYC is a complex oncogene, involving both fine protein dosage and cell-context dependency, and detailed understanding of MYC-mediated oncogenesis in T-ALL is still lacking. To better understand how MYC is interspersed in the complex T-ALL oncogenic networks, we performed the first thorough molecular and biochemical analysis of MYC activation in a comprehensive collection of primary adult and pediatric patient samples (n=163). RQ-PCR analysis first revealed that levels of MYC transcript are highly variable, and that high MYC expression can be generated in a large number of cases in absence of NOTCH1/FBXW7 mutations, suggesting the occurrence of multiple activation pathways in addition to NOTCH1. MYC protein levels were next assessed by western blot in a subpanel of 29 primary T-ALL samples. Although a large spectrum of protein expression was also observed, no direct correlation was apparent between transcript level and protein abundance. This discrepancy is in line with the frequent deregulation of factors controlling MYC protein turn-over in cancer cells. In Burkitt Lymphoma (BL) for example, mutations in the MYC-box (in and around the critical T58 phosphorylation site) impede efficient addressing to the proteasome, and results in oncogenic MYC protein stabilization. We sequenced the MYC-box region of 116 T-ALL samples and found no such mutations, suggesting that BL and T-ALL use different routes to achieve oncogenic MYC levels. An alternative candidate is the E3 ubiquitin ligase FBXW7 which has been shown to target both NOTCH1 and MYC for proteosomal degradation, and the loss-of-function mutations of which were previously shown to impair MYC protein stability. Although T-ALL harboring inactivating FBXW7 mutations were associated with high MYC protein level as expected, such mutants represented only 10% of the cases, and could thus not account for the numerous cases showing MYC protein accumulation in our series. This implied the frequent occurrence of other, alternative mechanisms of MYC stabilization in T-ALL. To identify these processes, we performed a detailed pan-genomic analysis of a T-ALL case showing high MYC protein levels at relapse but low MYC at diagnosis, despite identical transcript levels. Among a total of ten genomic aberrations found in this patient, only one difference was found between diagnosis and relapse, namely the progression of mono-allelic to bi-allelic deletion of a 10q23 region including the PTEN tumor suppressor gene. PTEN is considered the main negative regulator of the PI3K-AKT signaling. As AKT inactivates GSK3β, the serine-threonine kinase involved in MYC phosphorylation at T58, PTEN inactivation constitutes a likely candidate of MYC protein accumulation. To further test this hypothesis, we probed by western blot PTEN and MYC proteins in the previous subpanel of 29 T-ALL, and observed an inverse inter-relationship between PTEN and MYC protein levels. This anti-correlation was particularly clear in cases with abundant PTEN protein levels, where only faint MYC could be found despite relatively high transcription levels. Conversely, high MYC protein levels were in most cases associated with rather low PTEN protein levels. Finally, we functionally demonstrate that in T-ALL cell lines, the PI3K chemical inhibitor LY294002 which antagonizes AKT signaling and mimics PTEN function, is able to downmodulate MYC levels and activity. Altogether, our data reveals that post-transcriptional deregulation of MYC constitutes a major alternative pathway of MYC activation in T-ALL, operating partly via the PI3K/AKT axis through down-regulation of PTEN, and that NOTCH1 mutations might play a dual transcriptional and post-transcriptional role in this process. Our data lend further support to the significance of therapeutic targeting of MYC and/or the PTEN/AKT pathways, both in γ-secretase inhibitor-resistant and identified NOTCH1-independent/MYC-mediated T-ALL patients. Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Background: Graft-versus-host disease (GVHD) is a major cause of mortality after unrelated hematopoietic stem cell transplantations (HSCT). Despite the development of modern immunosuppressive strategies, a nearly perfectly controlled compatibility of the classical HLA genes (HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1) and availability of numerous so-called minor histocompatibility antigens (e.g. HY or HA-1), its incidence remains largely unexplained to date. MIC genes (MHC class I chain-related) - a distinct lineage of MHC class I genes – are promising candidates to explain, at least partially, the incidence of GVHD in HLA-matched transplantations. MICA and MICB are highly polymorphic (100 alleles for MICA and 40 for MICB) and encode functional cell-surface glycoproteins up-regulated by cell stress. They interact with NKG2D, an activating receptor expressed on the surface of cytotoxic αβ CD8+ and γδ T lymphocytes and natural killer cells. MIC genes are already known to have a HLA-independent effect on solid graft outcomes and may play a similar role in HSCT by triggering GVHD. Objective: The objective of the present study was to determine the impact of donor/patient matching at the MICA and MICB loci on the incidence of GVHD in patients undergoing unrelated HSCT. Methods: We retrospectively analyzed a multicenter cohort of 1072 unrelated transplantations performed between 1996 and 2013. All donor-recipient pairs were fully typed at high resolution for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 and were matched for ten of ten HLA alleles (HLA 10/10 matched). High resolution genotyping of MICA and MICB was performed by sequenced-based typing in order to define matching grades between donors and patients. The endpoints of the study were acute and chronic GVHD. Apart from HLA-DPB1 matching, statistical models were adjusted for major clinical variables which have been shown to be associated with outcome (patient’s age, patient’s and donor’s sex, patient’s and donor’s serological status for cytomegalovirus, year of transplantation, time to transplantation, transplantation center, source of stem cells, conditioning regimen, GVHD prophylaxis, treatment with anti-thymocyte globulin, disease category and severity at transplantation). Results: Of the 1072 transplantations, 134 (12.5 %) and 380 (35.4 %) were mismatched at the MICA and MICB locus, respectively. Both MICA and MICB mismatches were significantly associated with an increased incidence of severe acute GVHD (grades III-IV) in univariate and multivariate models (multivariate model: HR = 2.32, 95 % CI = 1.84-2.92; p=0.0003 for MICA and HR = 1.49, 95 % CI = 1.24-1.79; p=0.03 for MICB). At day 100 post-HSCT severe acute GVHD incidences in mismatched vs. matched transplantations were 19.62 % vs. 15.08 % and 20.00 % vs. 14.84 % for MICA and MICB, respectively (Figure 1). Chronic GVHD was associated with MICA and MICB mismatches in univariate analysis (HR = 1.55, 95 % CI = 1.27-1.89; p=0.029 for MICA and HR=1.38, 95 % CI = 1.19-1.62; p=0.03 for MICB), but showed only a trend for association in multivariate models. Figure 1 Estimated cumulative incidence curves of grades III–IV acute GVHD according to MICA (panel A) and MICB (panel B) matching status. The solid and dashed lines represent MIC matched and mismatched grafts, respectively. The Fine and Gray model was used with relapse and death considered as competing risks. Figure 1. Estimated cumulative incidence curves of grades III–IV acute GVHD according to MICA (panel A) and MICB (panel B) matching status. The solid and dashed lines represent MIC matched and mismatched grafts, respectively. The Fine and Gray model was used with relapse and death considered as competing risks. Conclusion: To date this is the largest reported MICA and MICB sequence analysis whether in HSCT or solid organ transplantation. Inclusion of MICA and MICB typing in the donor selection process may be a practical clinical strategy for lowering the risks of severe acute GVHD after unrelated HSCT. Disclosures No relevant conflicts of interest to declare.

Beschreibung: Introduction: Allogenic hematopoietic stem cell transplantation (SCT) is often the only curative treatment for a part of patients with malignant or benign hematological disorders. The availability of a HLA matched related or unrelated donor remains a major obstacle which can be resolved by the presence of alternative donors, like umbilical cord blood, partially matched unrelated or haploidentical family donors. T cell repleted SCT using haploidentical donors (H-SCT) has considerably improved over the last years due to better control of Graft Versus Host Disease (GVHD) using post-transplantation cyclophosphamide (PTCY). Our study aims to shed light on the interest of chimerism evaluation after H-SCT and to elucidate the cause of graft failure (GF) in our H-SCT recipients. Patients and methods: We conducted a retrospective study of 179 patients (pts) who received a H-SCT in our center from august 2009 to march 2016. The pts characteristics are reported in Table 1 and 2. One hundred sixty pts received a Reduced Intensity (RIC) and 19 pts a MyeloAblative Conditioning (MAC) regimen. Twenty-eight pts had refractory or relapsed acute myeloid leukemia. All pts received PTCY on days 3 and 4 and Ciclosporine A and mycophenolate of mofetil since day 5 for GVHD prophylaxis. Twenty pts received H-SCT for relapse after a first SCT with a HLA identical donor. Stem cell sources were bone marrow (BM) for 19 pts, peripheral blood stem cells (PBSC) for 157 pts and BM+PBSC for 3 pts. The donors were children (79 daughters sons), parents (4 fathers, 14 mothers), family members (75 siblings, 1 cousin, 1 nephew) and 5 unknown. Chimerism analysis: The peripheral blood CD3 positive cells were selected using the kit Human CD3 Positive selection (Stemcell) and genotyping was performed with the PowerPlex 18D System (Promega), a multiplex STR system allowing the co-amplification of 18 loci. DSAs (donor-specific anti-HLA antibodies): The DSAs were identified with the use of highly sensitive solid-phase immunoassays. Desensitization therapy with Bortezomib, Rituxan and plasmapheresis was performed in two patients with a high level of DSAs. Results: Chimerism could be evaluated in 167 patients, where 162 had ≥ 98% of donor cells at a median time of 35 d post-transplant (range 15-170) without secondary GF. One patient suffering from sickle disease had stable mixed chimerism (82% donor). Only 4 pts had primary GF (2%), all of donor-recipient pairs were ABO compatible, all of them received a Baltimore conditioning whereas 2 pts had BM as SC source. Recipients with PBSC as SC source had poor CD34+ cells infused (1,2 and 2,3 x 106/kg). One of the 4 pts had a high level of DSAs. A patient with mycosis fungoide had secondary GF after relapse (PBSC/DSAs negative). One patient with a high level of DSAs (78%) had a primary graft failure. Two pts with a high level of DSAs who were desensitized by the described procedure. Forty-five patients had a positive anti-HLA antibody no specific to donor with a median level of 3% (range: 1-45%) with no impact on engraftment (Anti-HLA antibody class I in 30 pts, class II in 11 pts and mixed in 4 pts). The median number of CD34+ cell count was 5,2x 106/kg (range: 1,3-17) in 160 pts who had PBCS as SC source. With a median follow up of 532 d (range: 164-1587d), 123 pts are alive and 116 of them are in CR. Conclusion: Full donor chimerism is obtained in almost all pts after T cell repleted H-SCT with PTCY. Primary graft failure occurred principally in pts with high levels of DSAs and poor graft CD34+ cells. Chimerism analysis post H-SCT is not crucial and might focus on a small group of high-risk pts. Detection of DSAs is crucial in HLA mismatched transplants not only to select the most appropriate donor but also to include a pre-transplantation strategy of desensitization to minimize the risk of graft failure. Disclosures No relevant conflicts of interest to declare.

Beschreibung: Introduction: Sickle cell disease (SCD) is one of the most common genetic disorders in the world and despite advances in best supportive care it remains a disease with high risk of morbidity and mortality. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative treatment modality. Reports of adults are limited because of the lack of suitable matched donors and the high treatment related toxicity (TRT) after conventional myeloablative conditioning regimen resulting from the accumulated disease specific end organ damage. Initial reports of non myeloablative conditioning regimen showed disappointing results because of the high risk of graft failure (GF) and disease recurrence. Recently, the development of reduced toxicity conditioning regimen (RTC) with lower TRT and the use of haploidentical family donors has widened the applicability of alloHSCT. Since SCD patients (pt) are highly alloimmunosized, donor HLA-specific antibodies (DSA) are often detectable and might compromise engraftment in HLA mismatched transplants. Material and Methods: We report a twenty two year old male pt with severe sickle cell-ß thalassemia and chronic blood transfusion related alloimmunization who received a family donor bone marrow alloHSCT from his haploidentical father. To reduce the risk of graft rejection, the preparative regimen consisted in a prephase-conditioning sequential immunoablation using two courses of a four day immunosuppressive treatment with fludarabine 40 mg/m2/d and dexamethasone 40 mg/d, six and three weeks before the start of the RIT conditioning regimen consisting of antithymocyte globuline (ATG, rabbit) 1.5 mg/kg from days -12 to -10; thiotepa 5 mg/kg on day -9; fludarabine 40 mg/m2 and intravenous busulfan 100 mg/kg from days -6 to -3. Graft versus host disease (GVHD) prophylaxis was provided by posttransplantation cyclophosphamide 50 mg/kg on day +3 and +4; cyclosporine and mycofenolate mofetil were started at day +5. The transplant work-up program included routine HLA antibody screening and prophylactic desensitization treatment with Rituxan combined with high dose immunoglobulin infusions after each cycle of immunoablation; additionally, plasmapheresis were performed at day -13 and -1, as well as one cycle of red blood cell exchange before the start of the RIT. Disease response was weekly measured by HbS levels using hemoglobin electrophoresis. Chimerism studies were done monthly by peripheral blood isolated CD3+ cells PCR analysis of variable number of nucleotide tandem repeats. DSA were examined using the luminex-based single antigen assay and MFI〉=1000 were considered positive. Results: The time to neutrophil recovery over 500 x 103/mm3 and platelet recovery over 50 x 103/mm3 were 29 and 43 days respectively; transfusion independency was reached at day +36. No GF occurred with predominantly donor mixed chimerism (82%) at last follow-up. HbS levels (baseline 68%) continuously decreased after the start of the preparative regimen to 〈 1% at day +77. DSA were substantially reduced after desensitization treatment and importantly dropped down further after alloHSCT to undetectable levels. Of note, no increase of DSA posttransplantation was observed. With a follow up of 140 days, the pt developed no GVHD or early TRT. Conclusions: We presume that our preparative regimen approach in association with posttransplantation cyclophosphamide provides sufficient T-cell depletion and tolerance induction to enhance durable donor engraftment. The presence of DSA should not be a barrier to HLA haploidentical related alloHSCT. Disclosures No relevant conflicts of interest to declare.

Beschreibung: INTRODUCTION: Matching all alleles of the HLA-A, -B, -C, and -DRB1 loci (8/8 match) is associated with the highest overall survival (OS) rates after unrelated donor (URD) hematopoietic stem cell transplantation (HSCT). In Europe, patients (pts) are also matched at the HLA-DQB1 loci (10/10 match), although there is no evidence of better OS. Data on Caucasian pts receiving a single HLA mismatch URD HSCT are still controversial. We therefore conducted a multicenter retrospective study to assess the impact of a single HLA mismatch (9/10 match) on outcomes after URD HSCT in a large cohort of French pts. METHODS: We collected data from 1092 pts who underwent HSCT between January 2000 and December 2012 at 32 French transplantation centers. Informed consent was obtained in accordance with the Declaration of Helsinki. High-resolution typing was performed for HLA-A, -B, -C, -DRB1, -DQB1 loci for all donor/recipient pairs. Clinical data were obtained through ProMISe (Project Manager Internet Server), an internet-based system shared by all French transplantation centers. Endpoints of interest were classical HSCT outcomes: engraftment, Graft versus host disease (GvHD), treatment related mortality (TRM) and relapse. GvHD free relapse free survival was also studied (defined as alive with no previous grade III-IV aGvHD, no moderate or severe chronic GvHD (cGvHD) and no relapse). Myeloablative conditioning was defined as a combination of agents expected to produce profound pancytopenia and myeloablation within 1-3 weeks after administration; pancytopenia is long lasting, usually irreversible and in most instances fatal, unless hematopoiesis is restored by hematopoietic stem cell infusion (Bacigalupo, et al.. Biology of Blood and Marrow Transplantation, 2009). Models were adjusted for disease risk, recipient age, CMV and sex matching, stem cell source, GVHD prophylaxis and conditioning regimen. For adjusted analysis DQB1 was used as the reference category. Disease risk was classified as standard or high risk using the American Society for Blood and Marrow Transplantation Request for Information 2006 risk scoring schema. RESULTS: Population characteristics are shown in Table 1. Gender balance was the only difference between groups (p4Gy [Hazard Ratio (HR) HR:1.95 (95% CI, 1.45 to 2.63)] and high disease risk [HR :1.34 (95% CI, 1.09 to 1.66)] were significantly associated with an increased cumulative incidence of grade II-IV aGVHD, whereas only MAC with TBI〉4Gy was a risk factor for grade III-IV aGVHD [HR:1.91 (95% CI, 1.28 to 2.87)].Overall Cumulative Incidence of cGVHD was 38.1% (95% CI, 35.9 to 40.1) at 84 months. Overall relapse rate was 33.8% (95% CI, 30.5 to 37.1) with no differences according to HLA mismatch subtype. CI of TRM was 36.0% (95% IC, 32.9 to 39.1). Single HLA-A mismatch [HR:1.55 (95% CI , 1.11 to 2.17)], high disease risk [HR:1.40 (1.12 to 1.74)], a female donor for a male recipient [HR:1.41 (1.10 to 1.79)], and the use of a MAC regimen [HR:1.50 (1.08 to 2.08)] were significantly associated with a higher TRM after adjusted analysis. Overall GRFS was 14.5% (12.1 to 17.3). Single HLA-A mismatch [HR:1.25 (95% IC, 1.01 to 1.54)] and high disease risk [HR:1.45 (95% IC, 1.26 to 1.67)] were significantly associated with a lower GRFS (Figure1). CONCLUSION: In this large cohort of Caucasian pts who received a single HLA mismatch URD HSCT, high disease risk was the major prognostic factor related to higher rates of both acute GvHD and treatment related mortality, and eventually a lower GRFS. HSCT outcomes were similar according to HLA single mismatches except for HLA-A mismatch, which was associated with a significant increase in TRM, and a worse GFRS. This study also highlights the high rates of both TRM and relapse after single mismatch URD HSCT (9/10) which justifies the use of reduced toxicity conditioning regimens, as well as the addition of targeted therapies pre- and post- HSCT in this setting. Disclosures Michallet: Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Astellas Pharma: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria. Peffault De Latour:Amgen: Research Funding; Alexion: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.

Beschreibung: From 1994 to 2000, 984 adults aged from 15 to 55 years with newly diagnosed Acute Lymphoblastic Leukemia (ALL) were eligible for randomization in the multicentric LALA-94 clinical protocol. The t(9;22), t(1;19) and t(4;11) translocations corresponding to BCR-ABL, E2A-PBX1 and MLL-AF4 fusion gene transcripts respectively, were considered as independent poor prognostic factors. Standardized RT-PCR analysis of these fusion gene transcripts were performed by 17 laboratories in order to provide data before the second randomization (J35) on 787 patients. In this multicentric study, validated data were available for therapeutic stratification for 91% of these analysed patients. No false positive RT-PCR was reported. Secondarily to retrospective BCR-ABL FISH, few false BCR-ABL negative RT-PCR were identified, leading to the design of new BIOMED-1 primers for b3-a3 junctions detection. Moreover, the LALA-94 study allowed to define new guidelines for molecular analysis at diagnosis. Like in other studies, the BCR-ABL transcript was found to be the most frequent molecular abnormality in B-ALL (24%) whereas MLL-AF4 and E2A-PBX1 were detected in 5% and 3.5% of B-ALL, respectively. Epidemiological and clinical data of MLL-AF4 and E2A-PBX1 were concordant with previous publications. Interestingly, because of the large number of reviewed patients, the different BCR-ABL subtypes (M-BCR and m-BCR) were statistically characterized by few clinical data. M-BCR subgroups had a higher age than m-BCR (p= 0.016) and occurs especially during the second semester (p= 0.034). Moreover, the comparison of clinical data at diagnosis of M-BCR variants showed that median age of b3a2 was statistically younger than b2a2 (p= 0.04) and that b3a2 occurs more frequently in man (p= 0.02). For the first time, these data suggest that these BCR-ABL breakpoints: m-BCR and M-BCR and also b2a2 and b2a3, are secondary to different physio-oncologic mechanisms even if therapeutic regimens including the same targeted therapy (tyrosine kinase inhibitor) for all BCR-ABL variants is the rule today.