RESUMO
Translation is regulated mainly in the initiation step, and its dysregulation is implicated in many human diseases. Several proteins have been found to regulate translational initiation, including Pdcd4 (programmed cell death gene 4). Pdcd4 is a tumor suppressor protein that prevents cell growth, invasion, and metastasis. It is downregulated in most tumor cells, while global translation in the cell is upregulated. To understand the mechanisms underlying translational control by Pdcd4, we used single-particle cryo-electron microscopy to determine the structure of human Pdcd4 bound to 40S small ribosomal subunit, including Pdcd4-40S and Pdcd4-40S-eIF4A-eIF3-eIF1 complexes. The structures reveal the binding site of Pdcd4 at the mRNA entry site in the 40S, where the C-terminal domain (CTD) interacts with eIF4A at the mRNA entry site, while the N-terminal domain (NTD) is inserted into the mRNA channel and decoding site. The structures, together with quantitative binding and in vitro translation assays, shed light on the critical role of the NTD for the recruitment of Pdcd4 to the ribosomal complex and suggest a model whereby Pdcd4 blocks the eIF4F-independent role of eIF4A during recruitment and scanning of the 5' UTR of mRNA.
Assuntos
Proteínas Reguladoras de Apoptose , Microscopia Crioeletrônica , Ligação Proteica , RNA Mensageiro , Proteínas de Ligação a RNA , Subunidades Ribossômicas Menores de Eucariotos , Humanos , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/química , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Subunidades Ribossômicas Menores de Eucariotos/metabolismo , Subunidades Ribossômicas Menores de Eucariotos/genética , Sítios de Ligação , Biossíntese de Proteínas , Fator de Iniciação 4A em Eucariotos/metabolismo , Fator de Iniciação 4A em Eucariotos/genética , Modelos MolecularesRESUMO
Messenger RNA (mRNA) recruitment to the 40S ribosomal subunit is mediated by eukaryotic initiation factor 4F (eIF4F). This complex includes three subunits: eIF4E (m7G cap-binding protein), eIF4A (DEAD-box helicase), and eIF4G. Mammalian eIF4G is a scaffold that coordinates the activities of eIF4E and eIF4A and provides a bridge to connect the mRNA and 40S ribosomal subunit through its interaction with eIF3. While the roles of many eIF4G binding domains are relatively clear, the precise function of RNA binding by eIF4G remains to be elucidated. In this work, we used an eIF4G-dependent translation assay to reveal that the RNA binding domain (eIF4G-RBD; amino acids 682-720) stimulates translation. This stimulating activity is observed when eIF4G is independently tethered to an internal region of the mRNA, suggesting that the eIF4G-RBD promotes translation by a mechanism that is independent of the m7G cap and mRNA tethering. Using a kinetic helicase assay, we show that the eIF4G-RBD has a minimal effect on eIF4A helicase activity, demonstrating that the eIF4G-RBD is not required to coordinate eIF4F-dependent duplex unwinding. Unexpectedly, native gel electrophoresis and fluorescence polarization assays reveal a previously unidentified direct interaction between eIF4G and the 40S subunit. Using binding assays, our data show that this 40S subunit interaction is separate from the previously characterized interaction between eIF4G and eIF3. Thus, our work reveals how eIF4F can bind to the 40S subunit using eIF3-dependent and eIF3-independent binding domains to promote translation initiation.
Assuntos
Fator de Iniciação 4E em Eucariotos , Biossíntese de Proteínas , Subunidades Ribossômicas Menores de Eucariotos , Humanos , Fator de Iniciação 3 em Eucariotos/química , Fator de Iniciação 3 em Eucariotos/metabolismo , Fator de Iniciação Eucariótico 4G/metabolismo , Ligação Proteica , Domínios Proteicos , Subunidades Ribossômicas Menores de Eucariotos/metabolismo , Subunidades Ribossômicas Menores de Eucariotos/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Fator de Iniciação 4E em Eucariotos/metabolismoRESUMO
A new in vitro system called Rec-Seq sheds light on how mRNA molecules compete for the machinery that translates their genetic sequence into proteins.
Assuntos
Biossíntese de Proteínas , Ribossomos , Ribossomos/metabolismo , RNA Mensageiro/metabolismoRESUMO
Eukaryotic translation initiation involves recruitment of the 43S pre-initiation complex to the 5' end of mRNA by the cap-binding complex eIF4F, forming the 48S translation initiation complex (48S), which then scans along the mRNA until the start codon is recognized. We have previously shown that eIF4F binds near the mRNA exit channel of the 43S, leaving open the question of how mRNA secondary structure is removed as it enters the mRNA channel on the other side of the 40S subunit. Here we report the structure of a human 48S that shows that, in addition to the eIF4A that is part of eIF4F, there is a second eIF4A helicase bound at the mRNA entry site, which could unwind RNA secondary structures as they enter the 48S. The structure also reveals conserved interactions between eIF4F and the 43S, probaby explaining how eIF4F can promote mRNA recruitment in all eukaryotes.
Assuntos
Fator de Iniciação 4F em Eucariotos , Iniciação Traducional da Cadeia Peptídica , Humanos , Fator de Iniciação 4F em Eucariotos/genética , Fator de Iniciação 4F em Eucariotos/metabolismo , RNA Mensageiro/metabolismo , Códon de Iniciação/metabolismo , Ribossomos/metabolismo , DNA Helicases/metabolismo , Biossíntese de Proteínas , Fator de Iniciação 4A em Eucariotos/química , Fator de Iniciação 4A em Eucariotos/genética , Fator de Iniciação 4A em Eucariotos/metabolismoRESUMO
INTRODUCTION: Letermovir is a cytomegalovirus (CMV) terminase complex inhibitor approved for prophylaxis of CMV infection and disease in adult CMV-seropositive allogeneic hematopoietic cell transplantation (allo-HCT) recipients (R+). We report pharmacokinetics (PK), safety, and efficacy of letermovir in adolescent (12-18 years) allogeneic HCT recipients from an ongoing clinical study. METHODS: In this phase 2b, multicenter, open-label study (NCT03940586), 28 adolescents received 480 mg letermovir [240 mg with cyclosporin A (CsA)] once daily orally or intravenously. Blood was collected for intensive (n = 14) plasma concentrations of letermovir. Intensive PK data were used for dose confirmation. Target exposure range 34,400-100,000 h × ng/mL for pediatric median exposures was based on model-predicted phase 3 population PK simulations in adult HCT recipients. RESULTS: All participants were CMV-seropositive (body weight 28.7-95.0 kg). Of 12 PK-evaluable participants, 8 receiving 480 mg letermovir without CsA and 4 receiving 240 mg letermovir with CsA achieved exposures comparable to the adult exposure range. Exposure above the target but below the adult clinical program maximum was observed in 1 patient. Safety was consistent with previously described safety in adults. The proportion of participants with clinically significant CMV infection through week 24 post-HCT was comparable (24%) to that in the pivotal phase 3 study in adults (37.5%). CONCLUSIONS: Administration of adult letermovir doses in this adolescent cohort resulted in exposures within adult clinical program margins and was associated with safety and efficacy similar to adults. Results support a letermovir dose of 480 mg (240 mg with CsA) in adolescent allo-HCT recipients.
Assuntos
Acetatos , Infecções por Citomegalovirus , Transplante de Células-Tronco Hematopoéticas , Quinazolinas , Adolescente , Criança , Humanos , Acetatos/efeitos adversos , Antivirais/efeitos adversos , Citomegalovirus , Infecções por Citomegalovirus/epidemiologia , Infecções por Citomegalovirus/prevenção & controle , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Quinazolinas/efeitos adversos , TransplantadosRESUMO
OBJECTIVES: The primary objectives of this study were to describe the demographics and clinical characteristics of patients who were treated with buprenorphine extended-release versus buprenorphine-naloxone sublingual tablets versus methadone in a real-world setting and to evaluate the difference in nonfatal overdose events between treatment cohorts. METHODS: This study was a retrospective chart review of patients with opioid use disorder initiating opioid agonist therapy in Canada during the outset of the COVID-19 pandemic (March 11, 2020 to October 31, 2021). Three treatment cohorts were defined by the initial prescribed opioid agonist therapy regimen: buprenorphine extended-release, buprenorphine-naloxone sublingual tablets, and methadone. Baseline characteristics, as well as treatment status, overdose events, and substance use 6 months after treatment initiation were collected using a standardized form. RESULTS: Nine clinics provided data on 379 patient cases. The incidence rate (number of events per 100 person-years) for a self-reported nonfatal overdose was 46.8 (n = 18), 19.3 (n = 10), and 1.7 (n = 1) in the methadone, buprenorphine-naloxone sublingual tablets, and buprenorphine extended-release cohorts, respectively. The risk-adjusted difference for the proportion of patients with nonfatal overdose was 8.59% (95% confidence interval, 3.10-14.08%; P = 0.0022) for methadone versus buprenorphine extended-release and 6.51% (95% confidence interval, 1.46-11.56%; P = 0.0115) for buprenorphine-naloxone sublingual tablets versus buprenorphine extended-release. CONCLUSIONS: Buprenorphine extended-release was associated with lower rates of nonfatal overdose events compared with daily opioid agonist therapy. Given the limitations of this naturalistic, retrospective design, further prospective studies are needed to validate these findings and demonstrate the potential for long-acting opioid agonist therapy in addressing the opioid crisis.
Assuntos
Buprenorfina , COVID-19 , Overdose de Drogas , Transtornos Relacionados ao Uso de Opioides , Humanos , Analgésicos Opioides , Combinação Buprenorfina e Naloxona , Pandemias , Estudos Retrospectivos , MetadonaRESUMO
Messenger RNA (mRNA) recruitment to the 40S ribosomal subunit is mediated by eukaryotic initiation factor 4F (eIF4F). This complex includes 3 subunits: eIF4E (m 7 G cap binding protein), eIF4A (DEAD box helicase), and eIF4G. Mammalian eIF4G is a scaffold that coordinates the activities of eIF4E and eIF4A and provides a bridge to connect the mRNA and 40S ribosomal subunit through its interaction with eIF3. While the roles of many eIF4G binding domains are relatively clear, the precise function of RNA binding by eIF4G remains to be elucidated. In this work, we used an eIF4G-dependent translation assay to reveal that the RNA binding domain (eIF4G-RBD; amino acids 682-720) stimulates translation. This stimulating activity is observed when eIF4G is independently tethered to an internal region of the mRNA, suggesting that the eIF4G-RBD promotes translation by a mechanism that is independent of the m 7 G cap and mRNA tethering. Using a kinetic helicase assay, we show that the eIF4G-RBD has a minimal effect on eIF4A helicase activity, demonstrating that the eIF4G-RBD is not required to coordinate eIF4F-dependent duplex unwinding. Unexpectedly, native gel electrophoresis and fluorescence polarization assays reveal a previously unidentified direct interaction between eIF4G and the 40S subunit. Using binding assays, our data show that this 40S subunit interaction is separate from the previously characterized interaction between eIF4G and eIF3. Thus, our work reveals how eIF4F can bind to the 40S subunit using eIF3-dependent and eIF3-independent binding domains to promote translation initiation.
RESUMO
The canonical DEAD-box helicase, eukaryotic initiation factor (eIF) 4A, unwinds 5' UTR secondary structures to promote mRNA translation initiation. Growing evidence has indicated that other helicases, such as DHX29 and DDX3/ded1p, also function to promote the scanning of the 40S subunit on highly structured mRNAs. It is unknown how the relative contributions of eIF4A and other helicases regulate duplex unwinding on an mRNA to promote initiation. Here, we have adapted a real-time fluorescent duplex unwinding assay to monitor helicase activity precisely in the 5' UTR of a reporter mRNA that can be translated in a cell-free extract in parallel. We monitored the rate of 5' UTR-dependent duplex unwinding in the absence or presence of an eIF4A inhibitor (hippuristanol), a dominant negative eIF4A (eIF4A-R362Q), or a mutant eIF4E (eIF4E-W73L) that can bind the m7G cap but not eIF4G. Our experiments reveal that the duplex unwinding activity in the cell-free extract is roughly evenly split between eIF4A-dependent and eIF4A-independent mechanisms. Importantly, we show that the robust eIF4A-independent duplex unwinding is not sufficient for translation. We also show that the m7G cap structure, and not the poly(A) tail, is the primary mRNA modification responsible for promoting duplex unwinding in our cell-free extract system. Overall, the fluorescent duplex unwinding assay provides a precise method to investigate how eIF4A-dependent and eIF4A-independent helicase activity regulates translation initiation in cell-free extracts. We anticipate that potential small molecule inhibitors could be tested for helicase inhibition using this duplex unwinding assay.
Assuntos
Fator de Iniciação 4A em Eucariotos , Fator de Iniciação 4E em Eucariotos , Processamento Pós-Transcricional do RNA , Humanos , Regiões 5' não Traduzidas , DNA Helicases/metabolismo , Fator de Iniciação 4A em Eucariotos/química , Fator de Iniciação 4E em Eucariotos/genética , Fator de Iniciação 4E em Eucariotos/metabolismo , Fator de Iniciação Eucariótico 4G/metabolismo , Biossíntese de Proteínas , RNA Helicases/genética , RNA Helicases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
AIM: To investigate the pharmacokinetics (PK) of intravenous treosulfan in paediatric patients undergoing haematopoietic stem cell transplantation (HSCT) for a broad range of diseases and to explore the impact of different dosing regimens on treosulfan exposure (area under the concentration-time curve, AUC0â∞ ) through dosing simulations. METHODS: A prospective multicentre PK study was conducted using treosulfan concentration data (n = 423) collected from 53 children (median age 3.5, range 0.2-17.0 years) receiving three daily age-guided doses (10-14 g/m2 ). Population PK modelling was performed using NONMEM software, utilising a stepwise forward selection backward elimination method and likelihood-ratio test for screening covariates to describe PK variability. Monte Carlo simulation was used to generate patient PK data for 10 000 virtual paediatric patients and cumulative AUC0â∞ values were evaluated using age, body surface area (BSA) and model-based dosing regimens, targeting 4800 mg*h/L. RESULTS: Treosulfan concentration data were described using a one-compartment PK model with first-order elimination. Population mean (95% CI) estimates for clearance (CL) and volume of distribution (V) were 16.3 (14.9-18.1) L/h and 41.9 (38.8-45.1) L, respectively. Allometrically scaled body weight was the best covariate descriptor for CL and V, and maturational age further explained variability in CL. Dosing simulations indicated that in young patient groups (<2 years), a model-based dosing regimen more accurately achieved the target AUC0â∞ (58.3%) over the age (42.6%) and BSA-based (51.3%) regimens. CONCLUSION: Treosulfan disposition was described through allometric body weight and maturational age descriptors. Model-informed dosing is recommended for patients under 2 years. Treosulfan PK parameters and AUC0â∞ were not influenced by patient disease.
Assuntos
Bussulfano , Transplante de Células-Tronco Hematopoéticas , Criança , Humanos , Lactente , Pré-Escolar , Adolescente , Estudos Prospectivos , Bussulfano/farmacocinética , Peso Corporal , Transplante de Células-Tronco Hematopoéticas/efeitos adversosRESUMO
Legionella pneumophila grows within membrane-bound vacuoles in alveolar macrophages during human disease. Pathogen manipulation of the host cell is driven by bacterial proteins translocated through a type IV secretion system (T4SS). Although host protein synthesis during infection is arrested by the action of several of these translocated effectors, translation of a subset of host proteins predicted to restrict the pathogen is maintained. To identify the spectrum of host proteins selectively synthesized after L. pneumophila challenge, macrophages infected with the pathogen were allowed to incorporate the amino acid analog azidohomoalanine (AHA) during a 2-h time window, and newly synthesized macrophage proteins were isolated by orthogonal chemistry followed by mass spectrometry. Among the proteins isolated were interferon-stimulated genes as well as proteins translated from highly abundant transcripts. Surprisingly, a large number of the identified proteins were from low-abundance transcripts. These proteins were predicted to be among the most efficiently translated per unit transcript in the cell based on ribosome profiling data sets. To determine if high ribosome loading was a consequence of efficient translation initiation, the 5' untranslated regions (5' UTR) of transcripts having the highest and lowest predicted loading levels were inserted upstream of a reporter, and translation efficiency was determined in response to L. pneumophila challenge. The efficiency of reporter expression largely correlated with predicted ribosome loading and lack of secondary structure. Therefore, determinants in the 5' UTR allow selected host cell transcripts to overcome a pathogen-driven translation blockade.
Assuntos
Legionella pneumophila , Humanos , Legionella pneumophila/fisiologia , Regiões 5' não Traduzidas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Interações Hospedeiro-Patógeno/genética , Vacúolos/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismoRESUMO
During translation initiation, the underlying mechanism by which the eukaryotic initiation factor (eIF) 4E, eIF4A, and eIF4G components of eIF4F coordinate their binding activities to regulate eIF4F binding to mRNA is poorly defined. Here, we used fluorescence anisotropy to generate thermodynamic and kinetic frameworks for the interaction of uncapped RNA with human eIF4F. We demonstrate that eIF4E binding to an autoinhibitory domain in eIF4G generates a high-affinity binding conformation of the eIF4F complex for RNA. In addition, we show that the nucleotide-bound state of the eIF4A component further regulates uncapped RNA binding by eIF4F, with a four-fold decrease in the equilibrium dissociation constant observed in the presence versus the absence of ATP. Monitoring uncapped RNA dissociation in real time reveals that ATP reduces the dissociation rate constant of RNA for eIF4F by â¼4-orders of magnitude. Thus, release of ATP from eIF4A places eIF4F in a dynamic state that has very fast association and dissociation rates from RNA. Monitoring the kinetic framework for eIF4A binding to eIF4G revealed two different rate constants that likely reflect two conformational states of the eIF4F complex. Furthermore, we determined that the eIF4G autoinhibitory domain promotes a more stable, less dynamic, eIF4A-binding state, which is overcome by eIF4E binding. Overall, our data support a model whereby eIF4E binding to eIF4G/4A stabilizes a high-affinity RNA-binding state of eIF4F and enables eIF4A to adopt a more dynamic interaction with eIF4G. This dynamic conformation may contribute to the ability of eIF4F to rapidly bind and release mRNA during scanning.
Assuntos
Fator de Iniciação 4A em Eucariotos , Fator de Iniciação 4E em Eucariotos , Humanos , Trifosfato de Adenosina/metabolismo , Fator de Iniciação 4A em Eucariotos/química , Fator de Iniciação 4E em Eucariotos/química , Fator de Iniciação 4F em Eucariotos/química , Fator de Iniciação Eucariótico 4G/química , Nucleotídeos/química , Ligação Proteica , RNA Mensageiro/metabolismoRESUMO
Translation initiation defines the identity and quantity of a synthesized protein. The process is dysregulated in many human diseases1,2. A key commitment step is when the ribosomal subunits join at a translation start site on a messenger RNA to form a functional ribosome. Here, we combined single-molecule spectroscopy and structural methods using an in vitro reconstituted system to examine how the human ribosomal subunits join. Single-molecule fluorescence revealed when the universally conserved eukaryotic initiation factors eIF1A and eIF5B associate with and depart from initiation complexes. Guided by single-molecule dynamics, we visualized initiation complexes that contained both eIF1A and eIF5B using single-particle cryo-electron microscopy. The resulting structure revealed how eukaryote-specific contacts between the two proteins remodel the initiation complex to orient the initiator aminoacyl-tRNA in a conformation compatible with ribosomal subunit joining. Collectively, our findings provide a quantitative and architectural framework for the molecular choreography orchestrated by eIF1A and eIF5B during translation initiation in humans.
Assuntos
Fator de Iniciação 1 em Eucariotos , Fatores de Iniciação em Eucariotos , RNA de Transferência de Metionina , Subunidades Ribossômicas , Microscopia Crioeletrônica , Fator de Iniciação 1 em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/genética , Humanos , RNA de Transferência de Metionina/genética , RNA de Transferência de Metionina/metabolismo , Subunidades Ribossômicas/química , Subunidades Ribossômicas/metabolismo , Imagem Individual de MoléculaRESUMO
This study aimed to characterize the population pharmacokinetics (PK) of busulfan focusing on how busulfan clearance (CL) changes over time during once-daily administration and assess different methods for measuring busulfan exposure and the ability to achieve target cumulative exposure under different dosing adjustment scenarios in pediatric stem cell transplantation recipients. Daily serial blood sampling was performed and concentration-time data were analyzed using a nonlinear mixed-effects approach. The developed PK model was used to assess achievement of target exposure under six dose-adjustment scenarios based on simulations performed in RStudio (RxODE package)®. A total of 2491 busulfan plasma concentration-time measurements were collected from 95 patients characterizing 379 dosing days. A two-compartment model with time-associated CL best described the data with a typical CL of 14.5 L/h for an adult male with 62 kg normal fat mass (NFM; equivalent to 70 kg total body weight), typical volume of distribution central compartment (V1) of 40.6 L/59 kg NFM (equivalent to 70 kg total body weight), and typical volume of distribution peripheral compartment of 3.57 L/62 kg NFM. Model interindividual variability in CL and V1 was 14.7% and 34.9%, respectively, and interoccasional variability in CL was 6.6%. Patient size described by NFM, a maturation component, and time since start of treatment significantly influenced CL. Simulations demonstrated that using model-based exposure estimates with each dose, and either a proportional dose-adjustment calculation or model-based calculated individual CL estimates to support dose adjustments, increased proportion of subjects attaining cumulative exposure within 5% of target compared with using noncompartmental analysis (100% vs. 0%). A time-associated reduction in CL during once-daily busulfan treatment was described.
Assuntos
Bussulfano , Administração Intravenosa , Adulto , Peso Corporal , Bussulfano/farmacocinética , Criança , Humanos , Cinética , MasculinoRESUMO
Malignant ascites is a common clinical problem in ovarian cancer. NK cells are present in the ascites, but their antitumor activity is inhibited. The underlying mechanisms of the inhibition have yet to be fully elucidated. Using an Fcγ receptor-mediated NK cell activation assay, we show that ascites from ovarian cancer patients potently inhibits NK cell activation. Part of the inhibitory activity is mediated by CA125, a mucin 16 fragment shed from ovarian cancer tumors. Moreover, transcriptional analyses by RNA sequencing reveal upregulation of genes involved in multiple metabolic pathways but downregulation of genes involved in cytotoxicity and signaling pathways in NK cells purified from ovarian cancer patient ascites. Transcription of genes involved in cytotoxicity pathways are also downregulated in NK cells from healthy donors after in vitro treatment with ascites or with a CA125-enriched protein fraction. These results show that ascites and CA125 inhibit antitumor activity of NK cells at transcriptional levels by suppressing expression of genes involved in NK cell activation and cytotoxicity. Our findings shed light on the molecular mechanisms by which ascites inhibits the activity of NK cells and suggest possible approaches to reactivate NK cells for ovarian cancer immunotherapy.
Assuntos
Ascite , Antígeno Ca-125 , Células Matadoras Naturais , Neoplasias Ovarianas , Ascite/metabolismo , Antígeno Ca-125/genética , Antígeno Ca-125/metabolismo , Feminino , Humanos , Células Matadoras Naturais/metabolismo , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Ativação TranscricionalRESUMO
INTRODUCTION: The Australian Technical Advisory Group on Immunisation and New Zealand Ministry of Health recommend all children aged ≥ 5 years receive either of the two mRNA COVID-19 vaccines: Comirnaty (Pfizer), available in both Australia and New Zealand, or Spikevax (Moderna), available in Australia only. Both vaccines are efficacious and safe in the general population, including children. Children and adolescents undergoing treatment for cancer and immunosuppressive therapy for non-malignant haematological conditions are particularly vulnerable, with an increased risk of severe or fatal COVID-19. There remains a paucity of data regarding the immune response to COVID-19 vaccines in immunosuppressed paediatric populations, with data suggestive of reduced immunogenicity of the vaccine in immunocompromised adults. RECOMMENDATIONS: Considering the safety profile of mRNA COVID-19 vaccines and the increased risk of severe COVID-19 in immunocompromised children and adolescents, COVID-19 vaccination is strongly recommended for this at-risk population. We provide a number of recommendations regarding COVID-19 vaccination in this population where immunosuppressive, chemotherapeutic and/or targeted biological agents are used. These include the timing of vaccination in patients undergoing active treatment, management of specific situations where vaccination is contraindicated or recommended under special precautions, and additional vaccination recommendations for severely immunocompromised patients. Finally, we stress the importance of upcoming clinical trials to identify the safest and most efficacious vaccination regimen for this population. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This consensus statement provides recommendations for COVID-19 vaccination in children and adolescents aged ≥ 5 years with cancer and immunocompromising non-malignant haematological conditions, based on evidence, national and international guidelines and expert opinion. ENDORSED BY: The Australian and New Zealand Children's Haematology/Oncology Group.
Assuntos
COVID-19 , Hematologia , Neoplasias , Adolescente , Austrália/epidemiologia , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Criança , Pré-Escolar , Humanos , Neoplasias/terapia , Nova Zelândia/epidemiologia , VacinaçãoRESUMO
Given sub-optimal HIV care outcomes for people living with HIV (PLWH) post-release from incarceration, we systematically searched peer-reviewed literature (2010-2021) describing controlled trial interventions aimed at improving Antiretroviral Therapy (ART) adherence and care linkage following release from correctional facilities for PLWH. Of 392 studies, 16 (4%) met the inclusion criteria. All studies were conducted in the United States and involved some form of intensive case management. Trials that scored highest in terms of study quality provided cell phones for engagement, reported sustained viral load suppression as a measurable outcome to infer ART adherence, and measured longitudinal data collected for at least 3-to-6 months following release. The two trials that demonstrated improved HIV viral load suppression involved Peer Navigators, and incentivized undetectable viral load, respectively. Facilitating support for addictions and addressing other social and structural barriers to achieving optimal health is also of vital importance in bridging care gaps for PLWH.
RESUMEN: Debido a los resultados suboptimos en los cuidados de las personas que viven con VIH después de su liberación del encarcelamiento, nosotros realizamos una revisión sistemática de la literatura (20102021) que describe ensayos control de intervenciones para mejorar la adherencia a la terapia antiretrovirales (TAR) y el vinculo con la atención medica después de la liberación del encarcelamiento de las personas que viven con VIH. De los 392 estudios, 16 (4%) cumplieron con los criterios de inclusión. Todos los estudios fueron realizados en los Estados Unidos e incluyen alguna forma de cuidados con manejo intensivo. Los ensayos que tenían los puntajes mas altos en términos de calidad proveían teléfonos celulares para la vinculación, reportaban supresión de la carga viral sostenida como medida indirecta de adherencia al TAR, y han medido datos longitudinales por lo menos de tres a seis meses después de la liberación carcelaria. Los dos ensayos que demostraron mejora en la supresión de la carga viral del VIH involucraban a los pares navegadores e incentivaban la carga viral no detectable, respectivamente. Facilitando el soporte para la adicción y el entendimiento de otras barreras sociales y estructurales para alcanzar una salud optima, es de vital importancia para superar las brechas en la atención de las personas que viven con VIH.
Assuntos
Direito Penal , Infecções por HIV , Antirretrovirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Adesão à Medicação , Carga ViralRESUMO
AIM: To assess the ability of model-based personalised dosing tools to estimate busulfan exposure (i) in comparison to clinically used intensive sampling exposure estimation procedure, (ii) using limited sampling strategies and (iii) to predict changes in busulfan clearance during busulfan treatment. METHODS: Data on intravenous busulfan dosing for patients with 4 consecutive days were entered into Bayesian forecasting software, InsightRX and NextDose. Prediction of busulfan cumulative exposure was compared to current clinical practice estimation, aiming for pre-defined individualised target of cumulative exposure. Estimation performance was tested given several limited sampling strategies. RESULTS: Thirty-two paediatric patients (0.2-16.5 years) provided a total of 103 daily exposure measurements estimated using 7 samples taken per day (full sampling), with 19 patients having sampling following all doses administered. Both software tools utilising Bayesian methods provided acceptable relative bias and precision of cumulative exposure estimations under the tested sampling scenarios. Relative bias ranged from median RE of 0.1-14.6% using InsightRX and from 3.4-7.8% using NextDose. Precision ranged from median RMSE of 0.19-0.32 mg·h·L-1 for InsightRX and 0.08-0.1 mg·h·L-1 for NextDose. A median reduction in busulfan clearance from day 1 to day 4 was observed in the clinical data (-10.9%), when using InsightRX (-18.6%) and with NextDose (-14.7%). CONCLUSION: Bayesian methods were shown to have relatively low bias and precisely estimate busulfan exposure using intensive sampling and several limited sampling strategies, which provides evidence for prospective studies to evaluate these tools in clinical practice. A trend to overestimation of exposure using Bayesian methods was observed compared to clinical practice. Reduction of busulfan clearance from day 1 to 4 of once daily dosing was confirmed and should be considered when adjusting doses.
Assuntos
Antineoplásicos Alquilantes/administração & dosagem , Bussulfano/administração & dosagem , Transplante de Células-Tronco Hematopoéticas/métodos , Modelos Biológicos , Administração Intravenosa , Adolescente , Antineoplásicos Alquilantes/farmacocinética , Teorema de Bayes , Bussulfano/farmacocinética , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Esquema de Medicação , Monitoramento de Medicamentos/métodos , Feminino , Humanos , Lactente , Masculino , Estudos Retrospectivos , SoftwareRESUMO
BACKGROUND: Recognition of viral nucleic acids is one of the primary triggers for a type I interferon-mediated antiviral immune response. Inborn errors of type I interferon immunity can be associated with increased inflammation and/or increased susceptibility to viral infections as a result of dysbalanced interferon production. NFX1-type zinc finger-containing 1 (ZNFX1) is an interferon-stimulated double-stranded RNA sensor that restricts the replication of RNA viruses in mice. The role of ZNFX1 in the human immune response is not known. OBJECTIVE: We studied 15 patients from 8 families with an autosomal recessive immunodeficiency characterized by severe infections by both RNA and DNA viruses and virally triggered inflammatory episodes with hemophagocytic lymphohistiocytosis-like disease, early-onset seizures, and renal and lung disease. METHODS: Whole exome sequencing was performed on 13 patients from 8 families. We investigated the transcriptome, posttranscriptional regulation of interferon-stimulated genes (ISGs) and predisposition to viral infections in primary cells from patients and controls stimulated with synthetic double-stranded nucleic acids. RESULTS: Deleterious homozygous and compound heterozygous ZNFX1 variants were identified in all 13 patients. Stimulation of patient-derived primary cells with synthetic double-stranded nucleic acids was associated with a deregulated pattern of expression of ISGs and alterations in the half-life of the mRNA of ISGs and also associated with poorer clearance of viral infections by monocytes. CONCLUSION: ZNFX1 is an important regulator of the response to double-stranded nucleic acids stimuli following viral infections. ZNFX1 deficiency predisposes to severe viral infections and a multisystem inflammatory disease.