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The introduction of all-trans retinoic acid (ATRA) combined with anthracyclines has significantly improved the outcomes for patients with acute promyelocytic leukemia (APL), and this strategy remains the standard of care in countries where arsenic trioxide is not affordable. However, data from national registries and real-world databases indicate that low- and middle-income countries (LMIC) still face disappointing results, mainly due to high induction mortality and suboptimal management of complications. The American Society of Hematology established the International Consortium on Acute Leukemias (ICAL) to address this challenge through international clinical networking. Here, we present the findings from the ICAPL study involving 806 patients with APL recruited in Brazil, Chile, Paraguay, Peru, and Uruguay. The induction mortality rate has decreased to 14.6% compared to the pre-ICAL rate of 32%. Multivariable logistic regression analysis revealed as factors associated with induction death: age ≥ 40 years, ECOG = 3, high-risk status based on the PETHEMA/GIMEMA classification, albumin level ≤ 3.5 g/dL, bcr3 PML/RARA isoform, the interval between presenting symptoms to diagnosis exceeding 48 hours, and the occurrence of central nervous system and pulmonary bleeding. With a median follow-up of 53 months, the estimated 4-year overall survival (OS) rate is 81%, the 4-year disease-free survival (DFS) rate is 80%, and the 4-year cumulative incidence of relapse (CIR) rate is 15%. These results parallel those observed in studies conducted in high-income countries, highlighting the long-term effectiveness of developing clinical networks to improve clinical care and infrastructure in LMIC.
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PURPOSE: This study investigated the effectiveness of algorithmic testing in hematopathology at the Brigham and Women's Hospital and Dana-Farber Cancer Institute (DFCI). The algorithm was predicated on test selection after an initial pathologic evaluation to maximize cost-effective testing, especially for expensive molecular and cytogenetic assays. MATERIALS AND METHODS: Standard ordering protocols (SOPs) for 17 disease categories were developed and encoded in a decision support application. Six months of retrospective data from application beta testing was obtained and compared with actual testing practices during that timeframe. In addition, 2 years of prospective data were also obtained from patients at one community satellite site. RESULTS: A total of 460 retrospective cases (before introduction of algorithmic testing) and 109 prospective cases (following introduction) were analyzed. In the retrospective data, 61.7% of tests (509 of 825) were concordant with the SOPs while 38.3% (316 of 825) were overordered and 30.8% (227 of 736) of SOP-recommended tests were omitted. In the prospective data, 98.8% of testing was concordant (244 of 247 total tests) with only 1.2% overordered tests (3 of 247) and 7.6% omitted tests (20 of 264 SOP-recommended tests; overall P < .001). The cost of overordered tests before implementing SOP indicates a potential annualized saving of $1,347,520 in US dollars (USD) in overordered testing at Brigham and Women's Hospital/DFCI. Only two of 316 overordered tests (0.6%) returned any additional information, both for extremely rare clinical circumstances. CONCLUSION: Implementation of SOPs dramatically improved test ordering practices, with a just right number of ancillary tests that minimizes cost and has no significant impact on acquiring key informative test results.
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Médula Ósea , Hospitales , Humanos , Femenino , Médula Ósea/patología , Estudios Retrospectivos , Biología MolecularRESUMEN
Background: Clonal hematopoiesis of indeterminate potential (CHIP) and clonal cytopenia of undetermined significance (CCUS) are defined by somatic mutations in genes associated with myeloid neoplasms (MN) at a variant allele fraction (VAF) ≥ 0.02, in the absence and presence of cytopenia, respectively. CHIP/CCUS is highly prevalent in adults and defining predictors of MN risk would aid clinical management and research. Methods: We analyzed sequenced exomes of healthy UK Biobank (UKB) participants (n = 438,890) in separate derivation and validation cohorts. Genetic mutations, laboratory values, and MN outcomes were used in conditional probability-based recursive partitioning and Cox regression to determine predictors of incident MN. Combined statistical weights defined a clonal hematopoiesis risk score (CHRS). Independent CHIP/CCUS patient cohorts were used to test prognostic capability of the CHRS in the clinical setting. Results: Recursive partitioning distinguished CHIP/CCUS cases with 10-year probabilities of MN ranging from 0.0078 - 0.85. Multivariable analysis validated partitioning variables as predictors of MN. Key features, including single DNMT3A mutations, high risk mutations, ≥ 2 mutations, VAF ≥ 0.2, age ≥ 65 years, CCUS vs CHIP and red blood cell indices, influenced MN risk in variable direction. The CHRS defined low risk (n = 10018, 88.4%), intermediate risk (n = 1196, 10.5%), and high risk (n = 123, 1.1%) groups. In clinical cohorts, most MN events occurred in high risk CHIP/CCUS patients. Conclusions: The CHRS provides simple prognostic framework for CHIP/CCUS, distinguishing a high risk minority from the majority of CHIP/CCUS which has minimal risk for progression to MN.
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T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.
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Linfohistiocitosis Hemofagocítica , Síndromes de Neurotoxicidad , Adulto , Humanos , Estados Unidos , Niño , Linfohistiocitosis Hemofagocítica/terapia , Linfohistiocitosis Hemofagocítica/etiología , Síndromes de Neurotoxicidad/etiología , Linfocitos T , Inmunoterapia Adoptiva/efectos adversos , Síndrome de Liberación de Citoquinas/terapia , Síndrome de Liberación de Citoquinas/complicacionesRESUMEN
In 2019, the Dana Farber/Mass General Brigham Hematology-Oncology Fellowship redesigned the 6-month Hematology training track/curriculum required for all fellows seeking to double board in hematology and oncology. Responding to both national and local trends suggesting a future shortage of hematologists, the goal of the redesign was to create a new curriculum that would increase fellow interest in hematology, improve fellows' clinical knowledge of hematology, and serve as an example to other Hematology-Oncology programs across the country. The revised track has now been in place for four years, and, in this paper, the authors present the fellow experience with the first four years of the redesigned curriculum. Based on the number of fellows who chose to complete the new curriculum, as well as the fellow evaluations and performance on the Hematology In-Training Exam, the authors conclude that the new curriculum has successfully increased both fellow interest in and knowledge of hematology.
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Becas , Hematología , Humanos , Encuestas y Cuestionarios , Educación de Postgrado en Medicina , Hematología/educación , CurriculumRESUMEN
Hemophagocytic lymphohistiocytosis (HLH) is a syndrome marked by a severe hyperinflammatory state characterized by aberrant T- and natural killer-cell activity leading to prolonged hypercytokinemia and can be rapidly fatal if not diagnosed and treated early. While upfront therapy is aimed at reducing hyperinflammation and controlling possible triggers, allogeneic hematopoietic stem cell transplantation (HSCT) is indicated for primary and relapsed/refractory cases to attain sustained remission. While this has been explored extensively in the pediatric population, there are limited data on adults undergoing HSCT for HLH. We analyzed transplant outcomes in an adult HLH population in the modern era who were transplanted at Dana-Farber Cancer Institute from 2010 onwards. Patients were uniformly transplanted on a reduced intensity platform incorporating early administration of alemtuzumab with standard infectious and graft-versus-host disease (GVHD) prophylaxis. Engraftment was documented for all patients. At 3 years after transplantation, overall survival (OS) was 75% (95% confidence interval [CI], 51-89) while 3-year progression-free survival (PFS) was 71% (95% CI, 46-86). The 3-year cumulative incidence of relapse was 15% (95% CI, 3.4-33). There were no isolated HLH relapses without relapse of malignancy. The cumulative incidence of nonrelapse mortality at 3 years was 15% (95% CI, 3.5-34). Infectious complications and GVHD outcomes were comparable to standard reduced-intensity conditioning (RIC) transplantation at our institute. Mixed chimerism was common but did not correlate with transplant outcomes. Our data suggest that the immune defect in HLH can be abrogated with allogeneic transplantation using a reduced intensity regimen with early administration of alemtuzumab as preconditioning, providing a potentially curative option for this difficult disease.
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Enfermedad Injerto contra Huésped , Linfohistiocitosis Hemofagocítica , Humanos , Niño , Adulto , Linfohistiocitosis Hemofagocítica/etiología , Linfohistiocitosis Hemofagocítica/terapia , Alemtuzumab/uso terapéutico , Acondicionamiento Pretrasplante , Trasplante Homólogo , Enfermedad Injerto contra Huésped/prevención & control , RecurrenciaRESUMEN
Neutrophilia and neutropenia commonly lead to inpatient hematology consultation. Quantitative neutrophil abnormalities have a broad differential and include diagnoses that are important to recognize because they may be associated with increased mortality. Neutrophilia can reflect etiologies such as infection, medications, inflammation, splenectomy, and congenital disorders. Neutropenia can arise from infection, medications, autoimmune destruction, sequestration, nutritional deficiency, malignancy, and congenital neutropenia syndromes. In the evaluation of all abnormalities of neutrophil number, the timing of the change, and the patient's historical neutrophil count are crucial.
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Trastornos Leucocíticos , Neutropenia , Humanos , Adulto , Neutrófilos , Pacientes Internos , Neutropenia/diagnóstico , Neutropenia/terapia , Neutropenia/etiología , Trastornos Leucocíticos/diagnóstico , Trastornos Leucocíticos/terapia , Leucocitosis/complicaciones , Derivación y ConsultaRESUMEN
Although a growing body of evidence demonstrates that altered mtDNA content (mtDNAc) has clinical implications in several types of solid tumours, its prognostic relevance in acute promyelocytic leukaemia (APL) patients remains largely unknown. Here, we show that patients with higher-than-normal mtDNAc had better outcomes regardless of tumour burden. These results were more evident in patients with low-risk of relapse. The multivariate Cox proportional hazard model demonstrated that high mtDNAc was independently associated with a decreased cumulative incidence of relapse. Altogether, our data highlights the possible role of mitochondrial metabolism in APL patients treated with ATRA.
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Leucemia Promielocítica Aguda , Humanos , Leucemia Promielocítica Aguda/tratamiento farmacológico , Leucemia Promielocítica Aguda/genética , Tretinoina/uso terapéutico , ADN Mitocondrial/genética , Relevancia Clínica , Recurrencia Local de Neoplasia/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Resultado del TratamientoRESUMEN
Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of multiorgan system dysfunction that is caused by hypercytokinemia and persistent activation of cytotoxic T lymphocytes and macrophages. A nearly ubiquitous finding and a diagnostic criterion of HLH is the presence of cytopenias in ≥ 2 cell lines. The mechanism of cytopenias in HLH is multifactorial but appears to be predominantly driven by suppression of hematopoiesis by pro-inflammatory cytokines and, to some extent, by consumptive hemophagocytosis. Recognition of cytopenias as a manifestation of HLH is an important consideration for patients with bone marrow failure of unclear etiology.
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Sickle cell disease (SCD) is a common condition within sub-Saharan Africa and associated with high under-5 mortality (U5M). The American Society of Hematology instituted the Consortium on Newborn Screening in Africa (CONSA) for SCD, a 7-country network of sites to implement standardized newborn hemoglobinopathy screening and early intervention for children with SCD in sub-Saharan Africa. CONSA's overall hypothesis is that early infant SCD screening and entry into standardized, continuous care will reduce U5M compared with historical estimates in the region. Primary trial objectives are to determine the population-based birth incidence of SCD and effectiveness of early standardized care for preventing early mortality consortium-wide at each country's site(s). Secondary objectives are to establish universal screening and early interventions for SCD within clinical networks of CONSA partners and assess trial implementation. Outcomes will be evaluated from data collected using a shared patient registry. Standardized trial procedures will be implemented among designated birth populations in 7 African countries whose programs met eligibility criteria. Treatment protocol includes administering antibacterial and antimalarial prophylaxis and standard childhood vaccinations against infections commonly affecting children with SCD. Infants with a positive screen and confirmation of SCD within the catchment areas defined by each consortium partner will be enrolled in the clinical intervention protocol and followed regularly until age of 5 years. Effectiveness of these early interventions, along with culturally appropriate family education and counseling, will be evaluated by comparing U5M in the enrolled cohort to estimated preprogram data. Here, we describe the methodology planned for this trial.
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Anemia de Células Falciformes , Tamizaje Neonatal , Lactante , Niño , Recién Nacido , Humanos , Preescolar , Tamizaje Neonatal/métodos , Anemia de Células Falciformes/diagnóstico , Anemia de Células Falciformes/epidemiología , Anemia de Células Falciformes/complicaciones , África del Sur del Sahara/epidemiología , IncidenciaRESUMEN
Myeloid neoplasms and acute leukemias derive from the clonal expansion of hematopoietic cells driven by somatic gene mutations. Although assessment of morphology plays a crucial role in the diagnostic evaluation of patients with these malignancies, genomic characterization has become increasingly important for accurate diagnosis, risk assessment, and therapeutic decision making. Conventional cytogenetics, a comprehensive and unbiased method for assessing chromosomal abnormalities, has been the mainstay of genomic testing over the past several decades and remains relevant today. However, more recent advances in sequencing technology have increased our ability to detect somatic mutations through the use of targeted gene panels, whole-exome sequencing, whole-genome sequencing, and whole-transcriptome sequencing or RNA sequencing. In patients with myeloid neoplasms, whole-genome sequencing represents a potential replacement for both conventional cytogenetic and sequencing approaches, providing rapid and accurate comprehensive genomic profiling. DNA sequencing methods are used not only for detecting somatically acquired gene mutations but also for identifying germline gene mutations associated with inherited predisposition to hematologic neoplasms. The 2022 International Consensus Classification of myeloid neoplasms and acute leukemias makes extensive use of genomic data. The aim of this report is to help physicians and laboratorians implement genomic testing for diagnosis, risk stratification, and clinical decision making and illustrates the potential of genomic profiling for enabling personalized medicine in patients with hematologic neoplasms.
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Neoplasias Hematológicas , Leucemia Mieloide Aguda , Trastornos Mieloproliferativos , Neoplasias , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Mutación , Genómica , Neoplasias/genética , Neoplasias Hematológicas/genética , Toma de Decisiones ClínicasRESUMEN
Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening inflammatory syndrome that may complicate hematologic malignancies (HMs). The appropriateness of current criteria for diagnosing HLH in the context of HMs is unknown because they were developed for children with familial HLH (HLH-2004) or derived from adult patient cohorts in which HMs were underrepresented (HScore). Moreover, many features of these criteria may directly reflect the underlying HM rather than an abnormal inflammatory state. To improve and potentially simplify HLH diagnosis in patients with HMs, we studied an international cohort of 225 adult patients with various HMs both with and without HLH and for whom HLH-2004 criteria were available. Classification and regression tree and receiver-operating curve analyses were used to identify the most useful diagnostic and prognostic parameters and to optimize laboratory cutoff values. Combined elevation of soluble CD25 (>3900 U/mL) and ferritin (>1000 ng/mL) best identified HLH-2004-defining features (sensitivity, 84%; specificity, 81%). Moreover, this combination, which we term the optimized HLH inflammatory (OHI) index, was highly predictive of mortality (hazard ratio, 4.3; 95% confidence interval, 3.0-6.2) across diverse HMs. Furthermore, the OHI index identified a large group of patients with high mortality risk who were not defined as having HLH according to HLH-2004/HScore. Finally, the OHI index shows diagnostic and prognostic value when used for routine surveillance of patients with newly diagnosed HMs as well as those with clinically suspected HLH. Thus, we conclude that the OHI index identifies patients with HM and an inflammatory state associated with a high mortality risk and warrants further prospective validation.
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Biomarcadores de Tumor/sangre , Ferritinas/sangre , Neoplasias Hematológicas/complicaciones , Subunidad alfa del Receptor de Interleucina-2/sangre , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/mortalidad , Anciano , Femenino , Estudios de Seguimiento , Humanos , Linfohistiocitosis Hemofagocítica/sangre , Linfohistiocitosis Hemofagocítica/etiología , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Tasa de SupervivenciaRESUMEN
INTRODUCTION: Immunomodulatory drugs used to treat multiple myeloma carry an increased risk of venous thromboembolic (VTE) disease. Previously published guidelines outline consensus opinion on how to mitigate this risk. METHODS: We collected baseline data to analyze how these strategies are utilized at our single institution and sought to improve the rates of anticoagulation for high-risk patients. This was done through a quality improvement project that added pharmacy/haematology oversight to the VTE risk assessment. RESULTS: Thirty-nine patients newly started on IMiDs were assessed for VTE risk. This information was passed on to the myeloma provider for consideration. Twenty-two patients were classified as high risk for VTE. Of the high-risk patients, 14 (64%) were placed on an anticoagulant for thromboprophylaxis. Eleven (79%) of the 14 used direct oral anticoagulants (DOACs). Eight high-risk patients did not receive an anticoagulant for thromboprophylaxis; 4 of these developed VTE. No patients on anticoagulation developed a VTE. This strategy had rare minor bleeding complications. CONCLUSION: This quality action verifies guideline-based thromboprophylaxis in multiple myeloma and supports the benefit of pharmacy oversight in improving VTE rates. The use of DOACs in myeloma should be further explored.
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Mieloma Múltiple , Farmacia , Tromboembolia Venosa , Anticoagulantes/uso terapéutico , Humanos , Agentes Inmunomoduladores , Mieloma Múltiple/complicaciones , Mieloma Múltiple/tratamiento farmacológico , Factores de Riesgo , Tromboembolia Venosa/prevención & controlRESUMEN
OBJECTIVE: Low-dose methotrexate (LD-MTX), a cornerstone in the treatment of rheumatoid arthritis, is associated with a moderately increased risk of anemia, leukopenia, and skin cancers, but the risks of myelosuppression and malignancy during LD-MTX use remain incompletely described. We examined the risks of cytopenias and skin cancers among patients taking LD-MTX versus placebo in a large randomized controlled trial (RCT). METHODS: We prespecified secondary analyses of a double-blind, placebo-controlled RCT that included adults with known cardiovascular disease and diabetes or metabolic syndrome in the United States and Canada. Subjects were randomly allocated to LD-MTX (20 mg/week maximum) or placebo. All subjects received folic acid (1 mg daily for 6days/week). We assessed the frequency of blindly adjudicated hematologic and malignant adverse events (AEs). RESULTS: A total of 2391 subjects were randomized to LD-MTX (mean dosage 14.9 mg/week), and 2395 were randomized to placebo. During follow-up, in the LD-MTX arm, simultaneous two-line cytopenias (n = 92 [3.9%]) or pancytopenia (n = 13 [0.54%]) were infrequent. Pancytopenia developed as soon as 4 months and as late as 3.5 years after beginning LD-MTX, though the latter subject had been recently diagnosed with multiple myeloma. Overall skin cancer risk was increased in users of LD-MTX compared with users of placebo, which driven largely by a statistically significant increased risk of squamous cell skin cancer (hazard ratio [HR] 3.31; 95% confidence interval [CI] 1.63-6.71). Melanoma was increased in LD-MTX, but this was not statistically significant (HR 2.33; 95% CI 0.60-9.01). CONCLUSIONS: Among subjects using LD-MTX, simultaneous two-line cytopenias and pancytopenia were uncommon. We found more cases of skin cancer, particularly squamous cell carcinomas, in the LD-MTX arm than the placebo arm.
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The SLIT-ROBO axis plays an important role in normal stem-cell biology, with possible repercussions on cancer stem cell emergence. Although the Promyelocytic Leukemia (PML) protein can regulate SLIT2 expression in the central nervous system, little is known about SLIT2 in acute promyelocytic leukemia. Hence, we aimed to investigate the levels of SLIT2 in acute promyelocytic leukemia (APL) and assess its biological activity in vitro and in vivo. Our analysis indicated that blasts with SLIT2high transcript levels were associated with cell cycle arrest, while SLIT2low APL blasts displayed a more stem-cell like phenotype. In a retrospective analysis using a cohort of patients treated with all-trans retinoic acid (ATRA) and anthracyclines, high SLIT2 expression was correlated with reduced leukocyte count (p = 0.024), and independently associated with improved overall survival (hazard ratio: 0.94; 95% confidence interval: 0.92-0.97; p < 0.001). Functionally, SLIT2-knockdown in primary APL blasts and cell lines led to increased cell proliferation and resistance to arsenic trioxide induced apoptosis. Finally, in vivo transplant of Slit2-silenced primary APL blasts promoted increased leukocyte count (p = 0.001) and decreased overall survival (p = 0.002) compared with the control. In summary, our data highlight the tumor suppressive function of SLIT2 in APL and its deteriorating effects on disease progression when downregulated.
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Adult-onset hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disease of immune hyperactivation. Unlike pediatric HLH, adult HLH is rarely driven by germline genetic variants. Although numerous precipitating etiologies have been identified, the reason that HLH occurs in only a subset of individuals and how other factors contribute to the disease remains unknown. We hypothesized that clonal hematopoiesis (CH), a state in which somatic mutations in blood cells cause an expanded population of mutant hematopoietic cells and drive an aberrant inflammatory state, could contribute to adult-onset HLH. In a highly annotated cohort of older adults with HLH we found that CH was more prevalent than in control cohorts. Using the adult-onset HLH mouse model in which repeated treatments of the TLR9 agonist, ODN1826, was delivered to the mouse, we observed that macrophages carrying mutations in Tet2, one of the most commonly mutated genes in CH, have an enhanced inflammatory response to TLR9 agonism. Finally, mice carrying Tet2 mutations in the hematopoietic compartment (a common model for CH) displayed an exaggerated response to TLR9 agonism, including worse splenomegaly and anemia. Our data suggest that CH is more common in individuals with adult-onset HLH and can contribute to the pathophysiology of this disease.
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Hematopoyesis Clonal , Linfohistiocitosis Hemofagocítica/metabolismo , Mutación , Adulto , Edad de Inicio , Anciano , Animales , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Dioxigenasas , Femenino , Humanos , Linfohistiocitosis Hemofagocítica/genética , Linfohistiocitosis Hemofagocítica/patología , Masculino , Ratones , Ratones Mutantes , Persona de Mediana Edad , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Receptor Toll-Like 9/agonistas , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/metabolismoRESUMEN
Non-T cell activation linker (NTAL) is a lipid raft-membrane protein expressed by normal and leukemic cells and involved in cell signaling. In acute promyelocytic leukemia (APL), NTAL depletion from lipid rafts decreases cell viability through regulation of the Akt/PI3K pathway. The role of NTAL in APL cell processes, and its association with clinical outcome, has not, however, been established. Here, we show that reduced levels of NTAL were associated with increased all-trans retinoic acid (ATRA)-induced differentiation, generation of reactive oxygen species, and mitochondrial dysfunction. Additionally, NTAL-knockdown (NTAL-KD) in APL cell lines led to activation of Ras, inhibition of Akt/mTOR pathways, and increased expression of autophagy markers, leading to an increased apoptosis rate following arsenic trioxide treatment. Furthermore, NTAL-KD in NB4 cells decreased the tumor burden in (NOD scid gamma) NSG mice, suggesting its implication in tumor growth. A retrospective analysis of NTAL expression in a cohort of patients treated with ATRA and anthracyclines, revealed that NTAL overexpression was associated with a high leukocyte count (P = 0.007) and was independently associated with shorter overall survival (Hazard Ratio: 3.6; 95% Confidence Interval: 1.17-11.28; P = 0.026). Taken together, our data highlights the importance of NTAL in APL cell survival and response to treatment.