RESUMO
BACKGROUND AIMS: Daratumumab, a human IgG monoclonal antibody targeting CD38, is a promising treatment for pediatric patients with relapsed or refractory T-cell acute lymphoblastic leukemia (T-ALL). We describe a case of delayed engraftment following a mismatched, unrelated donor hematopoietic stem cell transplant (HSCT) in a 14-year-old female with relapsed T-ALL, treated with daratumumab and chemotherapy. By Day 28 post-HSCT, the patient had no neutrophil engraftment but full donor myeloid chimerism. METHODS: We developed two novel, semi-quantitative, antibody-based assays to measure the patient's bound and plasma daratumumab levels to determine if prolonged drug exposure may have contributed to her slow engraftment. RESULTS: Daratumumab levels were significantly elevated more than 30 days after the patient's final infusion, and levels inversely correlated with her white blood cell counts. To clear daratumumab, the patient underwent several rounds of plasmapheresis and subsequently engrafted. CONCLUSIONS: This is the first report of both delayed daratumumab clearance and delayed stem cell engraftment following daratumumab treatment in a pediatric patient. Further investigation is needed to elucidate the optimal dosing of daratumumab for treatment of acute leukemias in pediatric populations as well as daratumumab's potential effects on hematopoietic stem cells and stem cell engraftment following allogenic HSCT.
Assuntos
Anticorpos Monoclonais , Transplante de Células-Tronco Hematopoéticas , Transplante Homólogo , Humanos , Transplante de Células-Tronco Hematopoéticas/métodos , Feminino , Anticorpos Monoclonais/uso terapêutico , Adolescente , Transplante Homólogo/métodos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/terapia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Sobrevivência de Enxerto/efeitos dos fármacosRESUMO
A 5-month-old infant with bone findings on x-ray presented an apparent contradiction including findings of both diffusely dense bones and rickets in the context of a history and laboratory investigation that suggested leukemia. Next generation gene panel sequencing revealed a TCIRG1 mutation which is consistent with autosomal recessive osteopetrosis. The paradoxical x-ray findings underscore a recently elucidated mechanism for the pathogenesis of a TCIRG mutation. This case highlights the importance of recognizing this radiographic, seeming contradictory, association in the context of a confusing clinical presentation. Failure to recognize this pattern promptly may lead to a delay in diagnosis, thus potentially permanent organ failure.
Assuntos
Osteopetrose , Raquitismo , ATPases Vacuolares Próton-Translocadoras , Lactente , Humanos , Osteopetrose/diagnóstico por imagem , Osteopetrose/genética , Osteopetrose/patologia , Raquitismo/diagnóstico por imagem , Radiografia , Mutação , ATPases Vacuolares Próton-Translocadoras/genéticaRESUMO
Neutrophils are critical mediators of host defense in pathogen-induced and sterile inflammation. Excessive neutrophil activation has been associated with increased host pathology through collateral organ damage. The beneficial aspects of neutrophil activation, particularly in sterile inflammation, are less well defined. We observed accumulation of nuclear debris in the lungs of neutropenic mice exposed to acid-induced injury compared with wild type. Size analysis of DNA debris showed that neutropenic mice were unable to degrade extracellular DNA fragments. In addition, we found that neutrophils are able to differentially express DNA-degrading and repair-associated genes and proteins. Once neutrophils are at sites of lung inflammation, they are able to phagocytose and degrade extracellular DNA. This neutrophil-dependent DNA degradation occurs in a MyD88-dependent pathway. The increased DNA debris in neutropenic mice was associated with dysregulated alveolar repair and the phenotype is rescued by intratracheal administration of DNase I. Thus, we show a novel mechanism as part of the inflammatory response, in which neutrophils engulf and degrade extracellular DNA fragments and allow for optimal organ repair.
Assuntos
Ácidos/efeitos adversos , Núcleo Celular/patologia , Lesão Pulmonar/patologia , Neutrófilos/patologia , Animais , Líquido da Lavagem Broncoalveolar , DNA/metabolismo , Espaço Extracelular/metabolismo , Fator Estimulador de Colônias de Granulócitos/deficiência , Fator Estimulador de Colônias de Granulócitos/metabolismo , Camundongos Endogâmicos C57BL , Fator 88 de Diferenciação Mieloide/metabolismo , Neutropenia/patologia , CicatrizaçãoRESUMO
AZD7442 (tixagevimab-cilgavimab) is a combination of two human monoclonal antibodies for pre-exposure prophylaxis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among high-risk patients who do not mount a reliable vaccine response. Foremost among these are hematologic malignancy patients with limited clinical trial or realworld experience to assess the effectiveness of this combination treatment since the emergence of Omicron and its subvariants. We performed a retrospective study of 892 high-risk hematologic malignancy patients who received AZD7442 at Memorial Sloan Kettering Cancer Center in New York City from January 1, 2022 to July 31, 2022. We evaluated demographic, clinical, and laboratory characteristics and performed regression analyses to evaluate risk factors for breakthrough infection. We also evaluated the impact of updated AZD7442 dosing regimens on the risk of breakthrough infection. Among 892 patients, 98 (10.9%) had a breakthrough infection during the study period. A majority received early outpatient treatment (82%) and eventually eight (8.2%) required hospitalization for management of Coronavirus Disease 2019 (COVID-19), with a single instance of severe COVID-19 and death. Patients who received a repeat dose or a higher firsttime dose of AZD7442 had a lower incidence of breakthrough infection. Univariate analyses did not reveal any significant predictors of breakthrough infection. While AZD7442 is effective at reducing SARS-CoV-2 breakthrough infection in patients with hematologic malignancies, no risk factors reliably predicted risk of infection. Patients who received updated dosing regimens as per Food and Drug Administration guidelines had better protection against breakthrough infection.
Assuntos
COVID-19 , Neoplasias Hematológicas , Profilaxia Pré-Exposição , Humanos , COVID-19/prevenção & controle , SARS-CoV-2 , Infecções Irruptivas , Estudos Retrospectivos , Anticorpos Monoclonais , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/tratamento farmacológicoRESUMO
The advent of chimeric antigen receptor T (CAR-T) and the burgeoning field of cellular therapy has revolutionized the treatment of relapsed/refractory leukemia and lymphoma. This personalized "living therapy" is highly effective against a number of malignancies, but this efficacy is tempered by side effects relatively unique to immunotherapies, including CAR-T. The overwhelming release of cytokines and chemokines by activated CAR-T and other secondarily activated immune effector cells can lead to cytokine release syndrome (CRS), which can have clinical and pathophysiology similarities to systemic inflammatory response syndrome and macrophage activating syndrome/hemophagocytic lymphohistiocytosis. Tocilizumab, an anti-IL6 receptor antibody, was recently FDA approved for treatment of CRS after CAR-T based on its ability to mitigate CRS in many patients. Unfortunately, some patients are refractory and additional therapies are needed. Patients treated with CAR-T can also develop neurotoxicity and, as the biology is poorly understood, current therapeutic interventions are limited to supportive care. Nevertheless, a number of recent studies have shed new light on the pathophysiology of CAR-T-related neurotoxicity, which will hopefully lead to effective treatments. In this review we discuss some of the mechanistic contributions intrinsic to the CAR-T construct, the tumor being treated, and the individual patient that impact the development and severity of CRS and neurotoxicity. As CAR-T and cellular therapy have redefined the concept of personalized medicine, so too will personalization be necessary in managing the unique side effects of these therapies.
Assuntos
Terapia Baseada em Transplante de Células e Tecidos , Imunoterapia Adotiva , Animais , Encefalopatias/etiologia , Terapia Baseada em Transplante de Células e Tecidos/efeitos adversos , Terapia Baseada em Transplante de Células e Tecidos/métodos , Síndrome da Liberação de Citocina/etiologia , Citocinas/metabolismo , Humanos , Imunoterapia Adotiva/efeitos adversos , Imunoterapia Adotiva/métodos , Neoplasias/imunologia , Neoplasias/metabolismo , Neoplasias/terapia , Síndromes Neurotóxicas/etiologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos Quiméricos/genética , Receptores de Antígenos Quiméricos/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
The congenital sideroblastic anemias (CSAs) are a heterogeneous group of inherited disorders of erythropoiesis characterized by pathologic deposits of iron in the mitochondria of developing erythroblasts. Mutations in the mitochondrial glycine carrier SLC25A38 cause the most common recessive form of CSA. Nonetheless, the disease is still rare, there being fewer than 70 reported families. Here we describe the clinical phenotype and genotypes of 31 individuals from 24 families, including 11 novel mutations. We also review the spectrum of reported mutations and genotypes associated with the disease, describe the unique localization of missense mutations in transmembrane domains and account for the presence of several alleles in different populations.
Assuntos
Anemia Sideroblástica/congênito , Genótipo , Proteínas de Transporte da Membrana Mitocondrial/genética , Mutação , Fenótipo , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
Unrelated donor hematopoietic stem cell transplantation (HSCT) is increasingly being used to cure nonmalignant hematologic diseases (NMHD) in patients who lack HLA matched related donors. Both graft rejection and graft-versus-host disease (GVHD) remain major barriers to safe and effective transplant for these patients requiring unrelated donors. Partial T cell depletion combined with peripheral stem cell transplantation (pTCD-PSCT) has the potential advantages of providing a high stem cell dose to facilitate rapid engraftment, maintaining cells that may facilitate engraftment, and decreasing GVHD risk compared with T cell-replete HSCT. Here, we report a single-institution, retrospective experience of unrelated donor pTCD-PSCT for pediatric patients with NMHD. From 2014 to 2017, 12 pediatric patients with transfusion-dependent NMHD underwent matched unrelated donor (MUD) or mismatched unrelated donor (MMUD) pTCD HSCT in our center using disease-specific conditioning. Donor PSCs underwent CD3+ T cell and CD19+ B cell depletion using CliniMACS, followed by a targeted addback of 1â¯×â¯105 CD3+ T cells/kg to the graft before infusion. All 12 patients demonstrated rapid trilinear engraftment. At a median follow-up of 740days (range, 279 to 1466), all patients were alive with over 92% total peripheral blood donor chimerism and without transfusion dependence or recurrence of their underlying hematologic disease. Immune reconstitution was rapid and comparable with T cell-replete HSCT. No patients developed severe acute GVHD (grades III to IV) or chronic extensive GVHD, and all patients had discontinued systemic immune suppression. Viral reactivations were common, but no patient developed symptoms of life-threatening infectious disease. Our data indicate that MUD and MMUD pTCD-PSCTs are safe and effective approaches that enable rapid engraftment and immune reconstitution, prevent severe GVHD, and expand availability of HSCT to any patients with NMHD who have closely MUDs.
Assuntos
Antígenos CD19 , Complexo CD3 , Doenças Hematológicas/terapia , Transplante de Células-Tronco Hematopoéticas/métodos , Histocompatibilidade , Depleção Linfocítica/métodos , Criança , Feminino , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Transfusão de Linfócitos/métodos , Masculino , Estudos Retrospectivos , Resultado do Tratamento , Doadores não RelacionadosAssuntos
Anemia Aplástica , Humanos , Anemia Aplástica/tratamento farmacológico , Anemia Aplástica/induzido quimicamente , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Segunda Neoplasia Primária/etiologia , Adulto , Antimetabólitos Antineoplásicos/efeitos adversos , Antimetabólitos Antineoplásicos/uso terapêutico , Azacitidina/efeitos adversos , Azacitidina/uso terapêutico , Metilação de DNA/efeitos dos fármacos , Idoso de 80 Anos ou mais , Síndromes Mielodisplásicas/tratamento farmacológicoRESUMO
PNH is the most common clonal hematopoietic disorder arising in patients with aAA. PNH is caused by mutations in PIGA, a gene that encodes the catalytic subunit of an enzyme involved in the biosynthesis of GPI anchors, transmembrane glycolipids required for cell surface expression of many proteins. PNH clones likely arise as immune escape mechanisms in aAA by preventing CD1D-restricted T-cell recognition of GPI anchors and GPI-linked autoantigens. Though many patients with aAA treated with IST will develop subclinical PNH clones, only a subset will develop PNH disease, characterized by increased thrombosis, intravascular hemolysis, and potential for severe organ dysfunction. In contrast to IST, allogeneic HSCT for patients with aAA is thought to cure bone marrow aplasia and prevent hematopoietic clonal evolution to PNH. Herein, we present a phenomenon of host-derived PNH disease arising in a patient with aAA many years following MSD-BMT, highlighting the importance of monitoring for this clonal disease in aAA patients with stable mixed donor/recipient chimerism after HSCT. We also provide a literature review for similar occurrences of PNH arising after HSCT.
Assuntos
Anemia Aplástica/terapia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Hemoglobinúria Paroxística/etiologia , Adolescente , Anemia Aplástica/genética , Células da Medula Óssea/metabolismo , Quimerismo , Ciclosporina/administração & dosagem , Diabetes Mellitus Tipo 1/complicações , Sobrevivência de Enxerto , Hemoglobinúria Paroxística/genética , Hemólise , Humanos , Imunossupressores/administração & dosagem , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mutação , Neutrófilos/metabolismo , Recidiva , Trombocitopenia/terapia , Trombose/etiologia , Resultado do TratamentoAssuntos
Candidíase Mucocutânea Crônica , Transplante de Células-Tronco Hematopoéticas , Humanos , Mutação com Ganho de Função , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais/genética , Anticorpos Neutralizantes/genética , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismo , Candidíase Mucocutânea Crônica/genéticaRESUMO
OBJECTIVES: To assess initial and long-term outcome of children with persistent/chronic idiopathic thrombocytopenic purpura (ITP) treated with 4 infusions of rituximab and three 4-day cycles of dexamethasone (4R+3Dex) including cohorts with most benefit and/or treatment associated toxicity. STUDY DESIGN: All pediatric patients with ITP at Weill-Cornell who received 4R+3Dex were included in this retrospective study. Duration was median time from first rituximab infusion to treatment failure. Patient cohort included 33 children ages 1-18 years with persistent/chronic ITP; 19 were female, 10 of whom were adolescents. Every patient had failed more than 1 and usually several ITP treatments. RESULTS: Children were treated with rituximab, 375 mg/m2 weekly for 4 weeks and three 4-day courses of dexamethasone 28 mg/m2 (40 mg max). Average age of nonresponders was 7.75 years, and initial responders averaged 12.7 years (P = .0073); 30% maintained continuing response at 60 months or last check-up. Eight of the 10 patients who underwent remission were female with ITP <24 months prior to initiating 4R+3Dex. All responding male patients except 2 relapsed. CONCLUSIONS: Durable unmaintained ITP remission after 4R+3Dex was seen almost exclusively in female adolescents with <24 months duration of ITP. This provides a new therapeutic paradigm for a subpopulation with hard-to-treat chronic ITP. The pathophysiology of ITP underlying this distinction requires further elucidation.
Assuntos
Anti-Inflamatórios/administração & dosagem , Dexametasona/administração & dosagem , Fatores Imunológicos/administração & dosagem , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Rituximab/administração & dosagem , Adolescente , Anti-Inflamatórios/uso terapêutico , Criança , Pré-Escolar , Doença Crônica , Dexametasona/uso terapêutico , Esquema de Medicação , Quimioterapia Combinada , Feminino , Seguimentos , Humanos , Fatores Imunológicos/uso terapêutico , Lactente , Infusões Intravenosas , Masculino , Estudos Retrospectivos , Rituximab/uso terapêutico , Resultado do TratamentoRESUMO
Severe congenital neutropenia (SCN) is caused by germline mutations, most commonly in ELANE, impacting neutrophil maturation and leading to high risk of life-threatening infections. Most patients with ELANE-mutant SCN can achieve safe neutrophil counts with chronic Granulocyte-Colony Stimulating Factor (G-CSF). However, up to 10% of patients have neutropenia refractory to G-CSF and require allogeneic stem cell transplant. Traditional conditioning for these patients includes busulfan and cyclophosphamide which is associated with significant toxicities. We present five patients with SCN without myeloid malignancy transplanted using a reduced toxicity regimen of busulfan, fludarabine and thymoglobulin. 5 pediatric patients with SCN underwent matched sibling donor bone marrow transplant (MSD-BMT) between 2014-2022 on or per CHP14BT057 (NCT02928991), a prospective, single center trial testing elimination of cyclophosphamide from conditioning in pediatric patients with single lineage inherited BMF syndromes. All patients had MSDs and no evidence of MDS. Conditioning consisted of PK-adjusted busulfan, fludarabine, and thymoglobulin, with calcineurin inhibitor and mycophenolate mofetil GVHD prophylaxis. With median follow-up of 48.4 months, overall and event-free survival were 100%. There was no acute GVHD and one instance of chronic limited GVHD. Patients exhibited >95% donor myeloid chimerism at 5 years post-BMT. Two patients experienced CMV reactivation without end-organ disease, and no other viral reactivation or significant infections occurred. MSD-BMT with reduced toxicity myeloablation for SCN provides excellent outcomes while minimizing toxicity. These data suggest that busulfan, fludarabine, and ATG can be considered an efficacious, low-toxicity standard of care regimen for patients with SCN undergoing MSD-BMT.
Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Neutropenia , Neutropenia/congênito , Humanos , Criança , Transplante de Medula Óssea/efeitos adversos , Síndrome Congênita de Insuficiência da Medula Óssea , Bussulfano/uso terapêutico , Bussulfano/farmacologia , Transplante de Células-Tronco Hematopoéticas/métodos , Irmãos , Estudos Prospectivos , Neutropenia/complicações , Ciclofosfamida/uso terapêutico , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/prevenção & controle , Fator Estimulador de Colônias de Granulócitos/uso terapêuticoRESUMO
Inherited bone marrow failure syndromes (IBMFS) are a group of heterogeneous disorders that account for â¼30% of pediatric cases of bone marrow failure and are often associated with developmental abnormalities and cancer predisposition. This article reports the laboratory validation and clinical utility of a large-scale, custom-designed next-generation sequencing panel, Children's Hospital of Philadelphia (CHOP) IBMFS panel, for the diagnosis of IBMFS in a cohort of pediatric patients. This panel demonstrated excellent analytic accuracy, with 100% sensitivity, ≥99.99% specificity, and 100% reproducibility on validation samples. In 269 patients with suspected IBMFS, this next-generation sequencing panel was used for identifying single-nucleotide variants, small insertions/deletions, and copy number variations in mosaic or nonmosaic status. Sixty-one pathogenic/likely pathogenic variants (54 single-nucleotide variants/insertions/deletions and 7 copy number variations) and 24 hypomorphic variants were identified, resulting in the molecular diagnosis of IBMFS in 21 cases (7.8%) and exclusion of IBMFS with a diagnosis of a blood disorder in 10 cases (3.7%). Secondary findings, including evidence of early hematologic malignancies and other hereditary cancer-predisposition syndromes, were observed in 9 cases (3.3%). The CHOP IBMFS panel was highly sensitive and specific, with a significant increase in the diagnostic yield of IBMFS. These findings suggest that next-generation sequencing-based panel testing should be a part of routine diagnostics in patients with suspected IBMFS.
Assuntos
Anemia Aplástica , Doenças da Medula Óssea , Hemoglobinúria Paroxística , Humanos , Criança , Anemia Aplástica/diagnóstico , Anemia Aplástica/genética , Doenças da Medula Óssea/diagnóstico , Doenças da Medula Óssea/genética , Síndrome Congênita de Insuficiência da Medula Óssea , Variações do Número de Cópias de DNA/genética , Reprodutibilidade dos Testes , Hemoglobinúria Paroxística/diagnóstico , Hemoglobinúria Paroxística/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , NucleotídeosRESUMO
EBV+ lymphomas constitute a significant cause of morbidity and mortality in recipients of allogeneic hematopoietic cell (HCT) and solid organ transplants (SOT). Phase I and II trials have shown that in HCT recipients, adoptive transfer of EBV-specific T-cells from the HCT donor can safely induce durable remissions of EBV+ lymphomas including 70->90% of patients who have failed to respond to treatment with Rituximab. More recently, EBV-specific T-cells generated from allogeneic 3rd party donors have also been shown to induce durable remission of EBV+ lymphomas in Rituximab refractory HCT and SOT recipients. In this review, we compare results of phase I and II trials of 3rd party and donor derived EBV-specific T-cells. We focus on the attributes and limitations of each product in terms of access, safety, responses achieved and durability. The limited data available regarding donor and host factors contributing to T cell persistence is also described. We examine factors contributing to treatment failures and approaches to prevent or salvage relapse. Lastly, we summarize strategies to further improve results for virus-specific immunotherapies for post-transplant EBV lymphomas.
Assuntos
Infecções por Vírus Epstein-Barr , Transplante de Células-Tronco Hematopoéticas , Linfoma , Transtornos Linfoproliferativos , Transplante de Órgãos , Humanos , Herpesvirus Humano 4 , Infecções por Vírus Epstein-Barr/complicações , Rituximab/uso terapêutico , Recidiva Local de Neoplasia/complicações , Transtornos Linfoproliferativos/etiologia , Transtornos Linfoproliferativos/terapia , Linfoma/terapia , Linfócitos T , Transplante de Órgãos/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Doadores de TecidosRESUMO
Acquired aplastic anemia (AA) is caused by autoreactive T cell-mediated destruction of early hematopoietic cells. Somatic loss of human leukocyte antigen (HLA) class I alleles was identified as a mechanism of immune escape in surviving hematopoietic cells of some patients with AA. However, pathogenicity, structural characteristics, and clinical impact of specific HLA alleles in AA remain poorly understood. Here, we evaluated somatic HLA loss in 505 patients with AA from 2 multi-institutional cohorts. Using a combination of HLA mutation frequencies, peptide-binding structures, and association with AA in an independent cohort of 6,323 patients from the National Marrow Donor Program, we identified 19 AA risk alleles and 12 non-risk alleles and established a potentially novel AA HLA pathogenicity stratification. Our results define pathogenicity for the majority of common HLA-A/B alleles across diverse populations. Our study demonstrates that HLA alleles confer different risks of developing AA, but once AA develops, specific alleles are not associated with response to immunosuppression or transplant outcomes. However, higher pathogenicity alleles, particularly HLA-B*14:02, are associated with higher rates of clonal evolution in adult patients with AA. Our study provides insights into the immune pathogenesis of AA, opening the door to future autoantigen identification and improved understanding of clonal evolution in AA.
Assuntos
Anemia Aplástica , Adulto , Humanos , Anemia Aplástica/genética , Anemia Aplástica/patologia , Alelos , Antígenos de Histocompatibilidade Classe I/genética , Antígenos HLA-B/genética , Antígenos HLA/genéticaRESUMO
Essentials The frequency of predicted loss-of-function (pLoF) variants in platelet-associated genes is unknown in the general population. Datasets like Genome Aggregation Database allow us to analyze pLoF variants with increased resolution. Expected prevalence of significant pLoF variants in platelet-associated genes in 0.329% in the general population. Platelet-associated genes that cause phenotypes due to haploinsufficiency are significantly depleted for deleterious variation. ABSTRACT: Background Inherited platelet disorders are being recognized more frequently as advanced sequencing technologies become more commonplace in clinical scenarios. The prevalence of each inherited platelet disorder and the disorders in aggregate are not known. This deficit in the field makes it difficult for clinicians to discuss results of sequencing assays and provide appropriate anticipatory guidance. Objectives In this study, we aim to calculate the prevalence of predicted loss-of-function variants in platelet-associated genes in the general population. Methods Here, we leverage the aggregation of exomes from the general population in the form of Genome Aggregation Database to assess 58 platelet-associated genes with phenotypic correlates. We use the loss-of-function transcript effect estimator (LOFTEE) to identify predicted loss-of-function mutations in these platelet-associated genes. These variants are curated and we then quantify the frequency of predicted loss-of-function variants in each gene. Results Our data show that 0.329% of the general population have a clinically meaningful predicted loss-of-function variant in a platelet-associated gene. Thus, these individuals are at risk for bleeding disorders that can range from mild to severe. Conclusions These data provide a novel lens through which clinicians can analyze sequencing results in their patients as well as an additional method to curate newly discovered platelet-associated genes in the future.
Assuntos
Transtornos Plaquetários , Transtornos Plaquetários/diagnóstico , Transtornos Plaquetários/genética , Exoma , Frequência do Gene , Haploinsuficiência , Humanos , FenótipoRESUMO
Iron-sulfur (Fe-S) clusters are required for mitochondrial function. Fe-S cluster synthesis occurs in the mitochondria and iron uptake is required for mitochondrial biogenesis. However, Fe-S clusters inhibit the expression of the iron importer transferrin receptor 1 (TfR1), whereas lack of the Fe-S cluster stimulates TfR1 expression. Yet, it is unclear whether Fe-S cluster synthesis increases with mitochondria biogenesis and, in turn, whether this negatively modulates TfR1 expression. We manipulated peroxisome proliferator-activated receptor-gamma coactivator-1α expression to control mitochondrial biogenesis in a variety of cell types, including erythroid cells. We demonstrated that Fe-S cluster synthesis increases with mitochondria biogenesis but does not interfere with increasing TfR1 expression. In fact, TfR1 expression is stimulated through alternative means to meet iron requirement for mitochondria biogenesis. Furthermore, under enhanced mitochondria biogenesis, increased Fe-S cluster synthesis inhibits the function of iron-regulating protein (IRP)1 and hence stimulates the expression of 5'-aminolevulinate synthase 2 (ALAS2), a target of IRP1 and rate-limiting enzyme in erythroid heme biogenesis. Increased ALAS2 expression leads to enhanced heme production, hemoglobinization, and erythropoiesis. Therefore, our study also provides a mechanism to link mitochondrial biogenesis with erythropoiesis and has a potential therapeutic value in the treatment of blood disorders.
Assuntos
Ferro/metabolismo , Biogênese de Organelas , Enxofre/metabolismo , Células 3T3-L1 , 5-Aminolevulinato Sintetase/genética , Animais , Transporte Biológico/efeitos dos fármacos , Células Eritroides/citologia , Células Eritroides/metabolismo , Eritropoese/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Heme/biossíntese , Hemoglobinas/metabolismo , Humanos , Camundongos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/farmacologiaRESUMO
Inherited bone marrow failure (IBMF) syndromes are rare blood disorders characterized by hematopoietic cell dysfunction and predisposition to hematologic malignancies. Despite advances in the understanding of molecular pathogenesis of these heterogeneous diseases, genetic variant interpretation, genotype-phenotype correlation, and outcome prognostication remain difficult. As new IBMF and other myelodysplastic syndrome (MDS) predisposition genes continue to be discovered (frequently in small kindred studies), there is an increasing need for a systematic framework to evaluate penetrance and prevalence of mutations in genes associated with IBMF phenotypes. To address this need, we analyzed population-based genomic data from >125 000 individuals in the Genome Aggregation Database for loss-of-function (LoF) variants in 100 genes associated with IBMF. LoF variants in genes associated with IBMF/MDS were present in 0.426% of individuals. Heterozygous LoF variants in genes in which haploinsufficiency is associated with IBMF/MDS were identified in 0.422% of the population; homozygous LoF variants associated with autosomal recessive IBMF/MDS diseases were identified in only .004% of the cohort. Using age distribution of LoF variants and 2 measures of mutational constraint, LOEUF ("loss-of-function observed/expected upper bound fraction") and pLI ("probability of being loss-of-function intolerance"), we evaluated the pathogenicity, tolerance, and age-related penetrance of LoF mutations in specific genes associated with IBMF syndromes. This analysis led to insights into rare IBMF diseases, including syndromes associated with DHX34, MDM4, RAD51, SRP54, and WIPF1. Our results provide an important population-based framework for the interpretation of LoF variant pathogenicity in rare and emerging IBMF syndromes.
Assuntos
Síndromes Mielodisplásicas , Biologia , Transtornos da Insuficiência da Medula Óssea , Proteínas de Ciclo Celular , Proteínas do Citoesqueleto , Estudos de Associação Genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Mutação , Síndromes Mielodisplásicas/genética , Proteínas Proto-Oncogênicas , RNA Helicases , Partícula de Reconhecimento de SinalRESUMO
Alveolar epithelial regeneration is essential for recovery from devastating lung diseases. This process occurs when type II alveolar pneumocytes (AT2 cells) proliferate and transdifferentiate into type I alveolar pneumocytes (AT1 cells). We used genome-wide analysis of chromatin accessibility and gene expression following acute lung injury to elucidate repair mechanisms. AT2 chromatin accessibility changed substantially following injury to reveal STAT3 binding motifs adjacent to genes that regulate essential regenerative pathways. Single-cell transcriptome analysis identified brain-derived neurotrophic factor (Bdnf) as a STAT3 target gene with newly accessible chromatin in a unique population of regenerating AT2 cells. Furthermore, the BDNF receptor tropomyosin receptor kinase B (TrkB) was enriched on mesenchymal alveolar niche cells (MANCs). Loss or blockade of AT2-specific Stat3, Bdnf or mesenchyme-specific TrkB compromised repair and reduced Fgf7 expression by niche cells. A TrkB agonist improved outcomes in vivo following lung injury. These data highlight the biological and therapeutic importance of the STAT3-BDNF-TrkB axis in orchestrating alveolar epithelial regeneration.