Multimodal cartography of human lymphopoiesis reveals B and T/NK/ILC lineages are subjected to differential regulation.

The developmental cartography of human lymphopoiesis remains incompletely understood. Here, we establish a multimodal map demonstrating that lymphoid specification follows independent direct or stepwise hierarchic routes converging toward the emergence of newly characterized CD117lo multi-lymphoid progenitors (MLPs) that undergo a proliferation arrest before entering the CD127- (NK/ILC/T) or CD127+ (B) lymphoid pathways. While the differentiation of CD127- early lymphoid progenitors is mainly driven by Flt3 signaling, emergence of their CD127+ counterparts is regulated cell-intrinsically and depends exclusively on the divisional history of their upstream precursors, including hematopoietic stem cells. Further, transcriptional mapping of differentiation trajectories reveals that whereas myeloid granulomonocytic lineages follow continuous differentiation pathways, lymphoid trajectories are intrinsically discontinuous and characterized by sequential waves of cell proliferation allowing pre-commitment amplification of lymphoid progenitor pools. Besides identifying new lymphoid specification pathways and regulatory checkpoints, our results demonstrate that NK/ILC/T and B lineages are under fundamentally distinct modes of regulation. (149 words).

Intraperitoneal transplant of Hepatocytes co-Encapsulated with mesenchymal stromal cells in modified alginate microbeads for the treatment of acute Liver failure in Pediatric patients (HELP)-An open-label, single-arm Simon's two stage phase 1 study protocol.

BACKGROUND: Pediatric acute liver failure (PALF) carries a high mortality without liver transplantation (LT) in children. Liver transplantation, though lifesaving, is limited by timely donor organ availability, the risks of major surgery and complications of life-long immunosuppression. Hepatocyte transplantation (HT) improves synthetic and detoxification functions in small animal models. The encapsulation of hepatocytes in alginate protects it from the recipient immune system while the intraperitoneal route of administration allows large volumes to be infused. The safety and possibly short-term efficacy of encapsulated hepatocytes has been observed in a named patient use. A novel type of microbeads (HMB002) has been developed, using a modified alginate and mesenchymal stromal cells (MSCs). Its safety and medium-term efficacy need to be studied in the context of clinical study while optimizing the hepatocyte function and viability using modifications of the alginate and MSCs co-encapsulation. METHODS: A single centre, non-randomised, open-label, single-arm Simon's two stage study will be conducted to evaluate the safety, biological activity and tolerability of transplantation of a single intraperitoneal dose of microbeads made from an optimum combination of a modified alginate, MSCs and hepatocytes in 17 patients less than 16 years of age with acute liver failure (Stage 1: 9 patients and Stage 2: 8 patient). Safety will be assessed by documenting moderate to severe (including life threatening and death) adverse events due to HMB002 in the first 52 weeks post-procedure. Tolerability will be assessed by observing the proportion of initiated infusions where >80% of infusion is received by the patient. Biological activity will be reflected in patient survival with native liver at 24 weeks post treatment. DISCUSSION: HMB002, if safe and efficacious in acute liver failure, could be a bridge until the liver regenerates or a suitable organ becomes available. There are multiple advantages to using HT. HT, when delivered by the intraperitoneal route, is less invasive than LT. Hepatocytes from a single donor liver can be used to treat multiple patients. Cryopreserved cells provide an off-the-shelf emergency treatment in PALF. When encapsulated, alginate encapsulation of hepatocytes precludes the need for immunosuppression unlike in LT.

Intratumoral pan-ErbB targeted CAR-T for head and neck squamous cell carcinoma: interim analysis of the T4 immunotherapy study.

BACKGROUND: Locally advanced/recurrent head and neck squamous cell carcinoma (HNSCC) is associated with significant morbidity and mortality. To target upregulated ErbB dimer expression in this cancer, we developed an autologous CD28-based chimeric antigen receptor T-cell (CAR-T) approach named T4 immunotherapy. Patient-derived T-cells are engineered by retroviral transduction to coexpress a panErbB-specific CAR called T1E28ζ and an IL-4-responsive chimeric cytokine receptor, 4αß, which allows IL-4-mediated enrichment of transduced cells during manufacture. These cells elicit preclinical antitumor activity against HNSCC and other carcinomas. In this trial, we used intratumoral delivery to mitigate significant clinical risk of on-target off-tumor toxicity owing to low-level ErbB expression in healthy tissues. METHODS: We undertook a phase 1 dose-escalation 3+3 trial of intratumoral T4 immunotherapy in HNSCC (NCT01818323). CAR T-cell batches were manufactured from 40 to 130 mL of whole blood using a 2-week semiclosed process. A single CAR T-cell treatment, formulated as a fresh product in 1-4 mL of medium, was injected into one or more target lesions. Dose of CAR T-cells was escalated in 5 cohorts from 1×107-1×109 T4+ T-cells, administered without prior lymphodepletion. RESULTS: Despite baseline lymphopenia in most enrolled subjects, the target cell dose was successfully manufactured in all cases, yielding up to 7.5 billion T-cells (67.5±11.8% transduced), without any batch failures. Treatment-related adverse events were all grade 2 or less, with no dose-limiting toxicities (Common Terminology Criteria for Adverse Events V.4.0). Frequent treatment-related adverse events were tumor swelling, pain, pyrexias, chills, and fatigue. There was no evidence of leakage of T4+ T-cells into the circulation following intratumoral delivery, and injection of radiolabeled cells demonstrated intratumoral persistence. Despite rapid progression at trial entry, stabilization of disease (Response Evaluation Criteria in Solid Tumors V.1.1) was observed in 9 of 15 subjects (60%) at 6 weeks post-CAR T-cell administration. Subsequent treatment with pembrolizumab and T-VEC oncolytic virus achieved a rapid complete clinical response in one subject, which was durable for over 3 years. Median overall survival was greater than for historical controls. Disease stabilization was associated with the administration of an immunophenotypically fitter, less exhausted, T4 CAR T-cell product. CONCLUSIONS: These data demonstrate the safe intratumoral administration of T4 immunotherapy in advanced HNSCC.

Femoral condyle bone mineral density in osteoarthritis differs significantly between knees with valgus vs. varus deformity.

BACKGROUND: The objective of this study was to measure bone mineral density (BMD) of the cancellous bone in both femoral condyles and to compare the results according to the hip-knee-ankle (HKA) angle in patients with knee osteoarthritis. HYPOTHESIS: BMD of cancellous bone in the medial condyle is markedly lower in valgus knees compared to that in the lateral condyle in varus knees. METHODS: Consecutive patients with computed tomography (CT) of the knee and long-leg radiographs obtained in preparation for total knee arthroplasty were included. The 189 knees were divided into five groups based on whether the hip-knee-ankle angle was<170° (major varus deformity), 171°-177° (varus deformity), 178°-182° (normal alignment), 183°-189° (valgus deformity), and>190° (major valgus deformity). A protocol for CT measurement of BMD values at the femoral condyles was developed. Correlations between the HKA angle and BMD were assessed using the ratio of medial-to-lateral condyle BMD values (M/L). RESULTS: M/L was lower for knees with valgus deformity than for normally aligned knees (0.7 vs. 1, p<0.001). This difference was larger in the group with major valgus deformity, with a mean M/L value of 0.5 (p<0.001). M/L was higher for knees with major varus (mean, 1.2; p=0.035). The correlation coefficients showed excellent intra-observer and inter-observer agreement for the BMD measurements. CONCLUSION: The BMD values of the femoral condyles correlate with the HKA angle. BMD is lower at the medial femoral condyle of valgus knees, particularly when the deformity exceeds 10°. This finding may deserve consideration when planning total knee arthroplasty. LEVEL OF EVIDENCE: IV; retrospective study.

Imatinib Optimized Therapy Improves Major Molecular Response Rates in Patients with Chronic Myeloid Leukemia.

The registered dose for imatinib is 400 mg/d, despite high inter-patient variability in imatinib plasmatic exposure. Therapeutic drug monitoring (TDM) is routinely used to maximize a drug's efficacy or tolerance. We decided to conduct a prospective randomized trial (OPTIM-imatinib trial) to assess the value of TDM in patients with chronic phase chronic myelogenous treated with imatinib as first-line therapy (NCT02896842). Eligible patients started imatinib at 400 mg daily, followed by imatinib [C]min assessment. Patients considered underdosed ([C]min < 1000 ng/mL) were randomized in a dose-increase strategy aiming to reach the threshold of 1000 ng/mL (TDM arm) versus standard imatinib management (control arm). Patients with [C]min levels ≥ 1000 ng/mL were treated following current European Leukemia Net recommendations (observational arm). The primary endpoint was the rate of major molecular response (MMR, BCR::ABL1IS ≤ 0.1%) at 12 months. Out of 133 evaluable patients on imatinib 400 mg daily, 86 patients had a [C]min < 1000 ng/mL and were randomized. The TDM strategy resulted in a significant increase in [C]min values with a mean imatinib daily dose of 603 mg daily. Patients included in the TDM arm had a 12-month MMR rate of 67% (95% CI, 51−81) compared to 39% (95% CI, 24−55) for the control arm (p = 0.017). This early advantage persisted over the 3-year study period, in which we considered imatinib cessation as a censoring event. Imatinib TDM was feasible and significantly improved the 12-month MMR rate. This early advantage may be beneficial for patients without easy access to second-line TKIs.

Identification of Gene Expression Profiles Associated with an Increased Risk of Post-Operative Recurrence in Crohn's Disease.

BACKGROUND AND AIMS: Ileocolonic resection is frequently needed in the course of Crohn's disease [CD] treatment and post-operative recurrence is extremely common. Our main objective was to analyse gene expression in the mucosa of CD patients at the time of surgery and at post-operative endoscopy, in order to identify predictors and mechanisms of early endoscopic recurrence. METHODS: We conducted transcriptome analyses on ileal mucosa samples collected from inflamed sections of the surgical specimens [n = 200], from ileal resection margins [n = 149] and in the neo-terminal ileum 6 months after surgery [n = 122]; these were compared with non-inflammatory bowel disease controls [n = 25]. The primary endpoint was post-operative endoscopic recurrence at 6 months. We applied regression models to identify gene signatures predicting endoscopic recurrence. RESULTS: Chronic inflammation was associated with strong expression of inflammatory genes [IL-6, IL-8, IL-1B] and decreased expression of genes involved in metabolic processes, but with a high inter-individual heterogeneity. Gene signatures associated with early endoscopic recurrence were mainly characterized by upregulation of TNFα, IFNγ, IL23A and IL17A. Pathway analyses showed that upregulation of mitochondrial dysfunction within the inflamed sections and JAK/STAT at the ileal margin were predictive of post-operative recurrence. A combined model integrating these top pathway signatures improved the prediction of endoscopic recurrence [area under the curve of 0.79]. STAT3 phosphorylation at the surgical ileal margin was associated with severe recurrence at 6 months. CONCLUSION: We identified several biological pathways in surgical ileal mucosa specimens associated with an increased risk of disease recurrence. Integration of the JAK/STAT and mitochondrial dysfunction pathways in the clinical model improved the prediction of post-operative recurrence.

Frequency and Genomic Aspects of Intrinsic Resistance to Vismodegib in Locally Advanced Basal Cell Carcinoma.

PURPOSE: Vismodegib is approved for the treatment of locally advanced basal cell carcinoma (laBCC), but some cases demonstrate intrinsic resistance (IR) to the drug. We sought to assess the frequency of IR to vismodegib in laBCC and its underlying genomic mechanisms. EXPERIMENTAL DESIGN: Response to vismodegib was evaluated in a cohort of 148 laBCC patients. Comprehensive genomic and transcriptomic profiling was performed in a subset of five intrinsically resistant BCC (IR-BCC). RESULTS: We identified that IR-BCC represents 6.1% of laBCC in the studied cohort. Prior treatment with chemotherapy was associated with IR. Genetic events that were previously associated with acquired resistance (AR) in BCC or medulloblastoma were observed in three out of five IR-BCC. However, IR-BCCs were distinct by highly rearranged polyploid genomes. Functional analyses identified hyperactivation of the HIPPO-YAP and WNT pathways at RNA and protein levels in IR-BCC. In vitro assay on the BCC cell line further confirmed that YAP1 overexpression increases the cell proliferation rate. CONCLUSIONS: IR to vismodegib is a rare event in laBCC. IR-BCCs frequently harbor resistance mutations in the Hh pathway, but also are characterized by hyperactivation of the HIPPO-YAP and WNT pathways.

Coronal knee alignment measurements differ on long-standing radiographs vs. by navigation.

BACKGROUND: The long-standing radiograph (LSR) is the reference tool for assessing knee alignment after total knee arthroplasty (TKA). However, its value is debatable, as many factors can influence measurement accuracy. Computer-assisted surgery (CAS) provides accurate measurements. Few studies have compared LSR and computer-assisted measurements of knee alignment. The objective of this study was to compare hip-knee-ankle (HKA) angle values obtained before and after TKA on LSRs to those obtained during CAS. HYPOTHESIS: The HKA angle values measured on LSRs before and after surgery are identical to those measured during CAS. MATERIAL AND METHODS: The HKA angles of 126 knees were measured on bipedal full-weight-bearing LSRs obtained before and 3 months after TKA. The results were compared to the values obtained during CAS. RESULTS: Before surgery, the standard deviation was 2.672, with limits of agreement of {-5.391; + 5.082}. The intra-class coefficients were good for the overall measurements (0.9), good for detecting>10° varus (0.89), fair for<10° varus and valgus (0.66 and 0.71, respectively), poor for>10° valgus (0.43) and poor for normal alignment (0). Post-operatively, the standard deviation was 3.113, with limits of agreement of {-6.426; +5.776}. The intra-class coefficient was poor for the overall measurements (0.20), negative for normal alignment (-0.05) and<10° valgus (-0.05), and positive for<10° varus (0.017) and for>10° varus and valgus (0.33). CONCLUSION: Before TKA, the LSR overestimates the deformity compared to CAS. After surgery, the two methods are not comparable. These findings underline the relevance of routinely obtaining LSRs and for using LSR results to estimate costs for healthcare insurance reimbursement purposes. LEVEL OF EVIDENCE: IV, retrospective observational cohort study.

Biological Effects of BET Inhibition by OTX015 (MK-8628) and JQ1 in NPM1-Mutated (NPM1c) Acute Myeloid Leukemia (AML).

BET inhibitors (BETi) including OTX015 (MK-8628) and JQ1 demonstrated antileukemic activity including NPM1c AML cells. Nevertheless, the biological consequences of BETi in NPM1c AML were not fully investigated. Even if of better prognosis AML patients with NPM1c may relapse and treatment remains difficult. Differentiation-based therapy by all trans retinoic acid (ATRA) combined with arsenic trioxide (ATO) demonstrated activity in NPM1c AML. We found that BETi, similar to ATO + ATRA, induced differentiation and apoptosis which was TP53 independent in the NPM1c cell line OCI-AML3 and primary cells. Furthermore, BETi induced proteasome-dependent degradation of NPM1c. BETi degraded NPM1c in the cytosol while BRD4 is degraded in the nucleus which suggests that restoration of the NPM1/BRD4 equilibrium in the nucleus of NPM1c cells is essential for the efficacy of BETi. While ATO + ATRA had significant biological activity in NPM1c IMS-M2 cell line, those cells were resistant to BETi. Gene profiling revealed that IMS-M2 cells probably resist to BETi by upregulation of LSC pathways independently of the downregulation of a core BET-responsive transcriptional program. ATO + ATRA downregulated a NPM1c specific HOX gene signature while anti-leukemic effects of BETi appear HOX gene independent. Our preclinical results encourage clinical testing of BETi in NPM1c AML patients.

PLZF Acetylation Levels Regulate NKT Cell Differentiation.

The transcription factor promyelocytic leukemia zinc finger (PLZF) is encoded by the BTB domain-containing 16 (Zbtb16) gene. Its repressor function regulates specific transcriptional programs. During the development of invariant NKT cells, PLZF is expressed and directs their effector program, but the detailed mechanisms underlying PLZF regulation of multistage NKT cell developmental program are not well understood. This study investigated the role of acetylation-induced PLZF activation on NKT cell development by analyzing mice expressing a mutant form of PLZF mimicking constitutive acetylation (PLZFON) mice. NKT populations in PLZFON mice were reduced in proportion and numbers of cells, and the cells present were blocked at the transition from developmental stage 1 to stage 2. NKT cell subset differentiation was also altered, with T-bet+ NKT1 and RORγt+ NKT17 subsets dramatically reduced and the emergence of a T-bet-RORγt- NKT cell subset with features of cells in early developmental stages rather than mature NKT2 cells. Preliminary analysis of DNA methylation patterns suggested that activated PLZF acts on the DNA methylation signature to regulate NKT cells' entry into the early stages of development while repressing maturation. In wild-type NKT cells, deacetylation of PLZF is possible, allowing subsequent NKT cell differentiation. Interestingly, development of other innate lymphoid and myeloid cells that are dependent on PLZF for their generation is not altered in PLZFON mice, highlighting lineage-specific regulation. Overall, we propose that specific epigenetic control of PLZF through acetylation levels is required to regulate normal NKT cell differentiation.

PPARγ agonists promote the resolution of myelofibrosis in preclinical models.

Myelofibrosis (MF) is a non-BCR-ABL myeloproliferative neoplasm associated with poor outcomes. Current treatment has little effect on the natural history of the disease. MF results from complex interactions between (a) the malignant clone, (b) an inflammatory context, and (c) remodeling of the bone marrow (BM) microenvironment. Each of these points is a potential target of PPARγ activation. Here, we demonstrated the therapeutic potential of PPARγ agonists in resolving MF in 3 mouse models. We showed that PPARγ agonists reduce myeloproliferation, modulate inflammation, and protect the BM stroma in vitro and ex vivo. Activation of PPARγ constitutes a relevant therapeutic target in MF, and our data support the possibility of using PPARγ agonists in clinical practice.

Prolonged in-hospital stay and higher mortality after Covid-19 among patients with non-Hodgkin lymphoma treated with B-cell depleting immunotherapy.

Prolonged Covid-19 is an emerging issue for patients with lymphoma or immune deficiency. We aimed to examine prolonged length of in-hospital stay (LOS) due to Covid-19 among patients with lymphoma and assess its determinants and outcomes. Adult patients with lymphoma admitted for Covid-19 to 16 French hospitals in March and April, 2020 were included. Length of in-hospital stay was analyzed as a competitor vs death. The study included 111 patients. The median age was 65 years (range, 19-92). Ninety-four patients (85%) had B-cell non-Hodgkin lymphoma. Within the 12 months prior to hospitalization for Covid-19, 79 patients (71%) were treated for their lymphoma. Among them, 63 (57%) received an anti-CD20 therapy. Fourteen patients (12%) had relapsed/refractory disease. The median LOS was 14 days (range, 1-235). After a median follow-up of 191 days (3-260), the 6-month overall survival was 69%. In multivariable analyses, recent administration of anti-CD20 therapy was associated with prolonged LOS (subdistribution hazard ratio 2.26, 95% confidence interval 1.42-3.6, p < 0.001) and higher risk of death (hazard ratio 2.17, 95% confidence interval 1.04-4.52, p = 0.039). An age ≥ 70 years and relapsed/refractory lymphoma were also associated with prolonged LOS and decreased overall survival. In conclusion, an age ≥ 70 years, a relapsed/refractory lymphoma and recent administration of anti-CD20 therapy are risk factors for prolonged LOS and death for lymphoma patients hospitalized for Covid-19. These findings may contribute to guide the management of lymphoma during the pandemic, support evaluating specific therapeutic approaches, and raise questions on the efficacy and timing of vaccination of this particular population.

Microtubules control nuclear shape and gene expression during early stages of hematopoietic differentiation.

Hematopoietic stem and progenitor cells (HSPC) can differentiate into all hematopoietic lineages to support hematopoiesis. Cells from the myeloid and lymphoid lineages fulfill distinct functions with specific shapes and intra-cellular architectures. The role of cytokines in the regulation of HSPC differentiation has been intensively studied but our understanding of the potential contribution of inner cell architecture is relatively poor. Here, we show that large invaginations are generated by microtubule constraints on the swelling nucleus of human HSPC during early commitment toward the myeloid lineage. These invaginations are associated with a local reduction of lamin B density, local loss of heterochromatin H3K9me3 and H3K27me3 marks, and changes in expression of specific hematopoietic genes. This establishes the role of microtubules in defining the unique lobulated nuclear shape observed in myeloid progenitor cells and suggests that this shape is important to establish the gene expression profile specific to this hematopoietic lineage. It opens new perspectives on the implications of microtubule-generated forces, in the early commitment to the myeloid lineage.

Late molecular recurrences in patients with chronic myeloid leukemia experiencing treatment-free remission.

Treatment-free remission (TFR) is an opportunity for patients with chronic myeloid leukemia (CML). Reported cumulative incidence curves of molecular recurrence (MRec) arbor a 2-phase shape with mainly early events, but also some late events (late MRec [LMRec]). Having discontinued our first patient in 2004, we have access to a prolonged follow-up, enabling us to characterize these late events. Over 15 years, 128 patients from our institution were registered in the Stop Imatinib (STIM; A Study for Tyrosine Kinase Inhibitors Discontinuation [A-STIM]) trial. MRec was defined by the loss of major molecular response (BCR-ABL1IS >0.1%). At the first TFR attempt, patients had been taking a tyrosine kinase inhibitor for a median of 7.1 years and in BCR-ABL1IS ≤0.01% (MR4) for a median of 4 years. The median follow-up of patients in TFR was 6.5 years. The TFR rate was estimated to be 45.6% after 7 years. For 9/65 (14%) patients experiencing MRec, recurrence occurred after 2 years in TFR (median, 3.6 years). The residual rate of MRec after 2 years was estimated to be 18%. The probability of remaining in TFR was 65.4% for patients having experienced fluctuations of their minimal residual disease (MRD) (at least 2 consecutive measurements BCR-ABL1IS >0.0032% or loss of MR4), whereas it was 100% for those with stable MRD (P = .003). After 2 years in TFR, we observed an 18% residual rate of LMRec. These late events represent 14% of all MRec and occur in patients with fluctuating MRD measurements. A long-term molecular follow-up therefore remains mandatory for CML patients in TFR. The A-STIM study was registered at www.clinicaltrials.gov as #NCT02897245.

Long-Term Follow-Up and Optimization of Interleukin-1 Inhibitors in the Management of Monogenic Autoinflammatory Diseases: Real-Life Data from the JIR Cohort.

Objectives: The major role of interleukin (IL)-1 in the pathogenesis of hereditary recurrent fever syndromes favored the employment of targeted therapies modulating IL-1 signaling. However the best use of IL1 inhibitors in terms of dosage is difficult to define at present. Methods: In order to better understand the use of IL1 inhibitors in a real-life setting, our study assessed the dosage regimens of French patients with one of the four main hereditary recurrent fever syndromes (Familial Mediterranean Fever (FMF), TNF receptor associated periodic syndrome (TRAPS), cryopyrin associated periodic fever (CAPS) and mevalonate kinase deficiency). The patients were retrieved retrospectively from the JIR cohort, an international platform gathering data of patients with pediatric inflammatory diseases. Results: Forty five patients of the JIR cohort with a hereditary recurrent fever syndrome had received at least once an IL1 inhibitor (anakinra or canakinumab). Of these, 43% received a lower dosage than the one suggested in the product recommendations, regardless of the type of the IL1 inhibitor. Especially patients with FMF and TRAPS seemed to need lower treatment regimens; in our cohort none of the FMF or TRAPS patients received an intensified dose of IL-inhibitor. On-demand treatment with a short half-life IL-1 inhibitor has also been used successfully for some patients with one of these two conditions The standard dose was given to 42% of the patients; whereas an intensified dose of IL-1 inhibitors was given to 15% of the patients (44% of CAPS patients and 17% of mevalonate kinase deficiency patients). In our cohort each individual patient's need for treatment seemed highly variable, ranging from on demand treatment regimens to intensified dosage maintenance therapies depending on the activity and the severity of the underlying disease. Conclusion: IL-1 inhibitors are a good treatment option for patients with a hereditary recurrent fever syndrome, but the individual need of the dosage of IL-1 inhibitors to control the disease effectively seems highly variable. Severity, activity but also the type of the underlying disease, belong to the parameters underpinning the treat-to-target strategy implemented in an everyday life practice.

BET inhibitors impair leukemic stem cell function only in defined oncogenic subgroups of acute myeloid leukaemias.

Bromodomain and Extra-Terminal inhibitors (BETi) such as OTX015 are active in Acute Myeloid Leukaemias (AML). Their activity on Leukemic Stem Cells (LSCs) is less documented. We interrogated the anti-LSC activity of OTX015 in a niche-like long-term culture in 26 primary AML samples and validated our findings in vivo. OTX015 impaired LSCs in AMLs harbouring Core Binding Factor or KMT2A gene fusions, NPM1 or chromatin/spliceosome genes mutations, but not in those with aneuploidy/TP53 mutations. In four patients, we dissected the transcriptomic footprint of Bet inhibition on LSCs versus blasts. Our results can instruct future clinical trials of BETi in AML.

Using healthcare claims data to analyze the prevalence of BCR-ABL-positive chronic myeloid leukemia in France: A nationwide population-based study.

BACKGROUND: Data on Chronic Myeloid Leukemia (CML) prevalence are scarce. Here we provide an estimation of the prevalence of CML in France for the year 2014 using French national health insurance data. METHODS: We selected patients claiming reimbursement for tyrosine kinase inhibitors (TKI) or with hospital discharge diagnoses for CML, BCR/ABL-positive or with full reimbursement of health care expenses for myeloid leukemia. We built an algorithm which we validated on a random sample of 100 potential CML patients by comparing the results obtained using the algorithm and the opinion of two hematologists who reviewed the patient demographics and sequence of care abstracted from claims data (internal validity). For external validity, we compared the number of incident CML patients identified using the algorithm with those recorded in French population-based cancer registries in departments covered by such a registry. RESULTS: We identified 10 789 prevalent CML patients in 2014, corresponding to a crude prevalence rate of 16.3 per 100 000 inhabitants [95% confidence interval (CI) 16.0-16.6]: 18.5 in men [18.0-19.0] and 14.2 in women [13.8-14.6]. The crude CML prevalence was less than 1.6 per 100 000 [1.2-2.0] under age 20, increasing to a maximum of 48.2 [45.4-51.2) at ages 75-79. It varied from 10.2 to 23.8 per 100 000 across French departments. The algorithm showed high internal and external validity. Concordance rate between the algorithm and the hematologists was 96%, and the numbers of incident CML patients identified using the algorithm and the registries were 162 and 150, respectively. CONCLUSION: We built and validated an algorithm to identify CML patients in administrative healthcare databases. In addition to prevalence estimation, the algorithm could be used for future economic evaluations or pharmaco-epidemiological studies in this population.

Deletion 6q Drives T-cell Leukemia Progression by Ribosome Modulation.

Deletion of chromosome 6q is a well-recognized abnormality found in poor-prognosis T-cell acute lymphoblastic leukemia (T-ALL). Using integrated genomic approaches, we identified two candidate haploinsufficient genes contiguous at 6q14, SYNCRIP (encoding hnRNP-Q) and SNHG5 (that hosts snoRNAs), both involved in regulating RNA maturation and translation. Combined silencing of both genes, but not of either gene alone, accelerated leukemogeneis in a Tal1/Lmo1/Notch1-driven mouse model, demonstrating the tumor-suppressive nature of the two-gene region. Proteomic and translational profiling of cells in which we engineered a short 6q deletion by CRISPR/Cas9 genome editing indicated decreased ribosome and mitochondrial activities, suggesting that the resulting metabolic changes may regulate tumor progression. Indeed, xenograft experiments showed an increased leukemia-initiating cell activity of primary human leukemic cells upon coextinction of SYNCRIP and SNHG5. Our findings not only elucidate the nature of 6q deletion but also highlight the role of ribosomes and mitochondria in T-ALL tumor progression. SIGNIFICANCE: The oncogenic role of 6q deletion in T-ALL has remained elusive since this chromosomal abnormality was first identified more than 40 years ago. We combined genomic analysis and functional models to show that the codeletion of two contiguous genes at 6q14 enhances malignancy through deregulation of a ribosome-mitochondria axis, suggesting the potential for therapeutic intervention.This article is highlighted in the In This Issue feature, p. 1494.