POLE Mutation Spectra Are Shaped by the Mutant Allele Identity, Its Abundance, and Mismatch Repair Status.

Human tumors with exonuclease domain mutations in the gene encoding DNA polymerase ε (POLE) have incredibly high mutation burdens. These errors arise in four unique mutation signatures occurring in different relative amounts, the etiologies of which remain poorly understood. We used CRISPR-Cas9 to engineer human cell lines expressing POLE tumor variants, with and without mismatch repair (MMR). Whole-exome sequencing of these cells after defined numbers of population doublings permitted analysis of nascent mutation accumulation. Unlike an exonuclease active site mutant that we previously characterized, POLE cancer mutants readily drive signature mutagenesis in the presence of functional MMR. Comparison of cell line and human patient data suggests that the relative abundance of mutation signatures partitions POLE tumors into distinct subgroups dependent on the nature of the POLE allele, its expression level, and MMR status. These results suggest that different POLE mutants have previously unappreciated differences in replication fidelity and mutagenesis.

Combined analyses of within-host SARS-CoV-2 viral kinetics and information on past exposures to the virus in a human cohort identifies intrinsic differences of Omicron and Delta variants.

The emergence of successive Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) during 2020 to 2022, each exhibiting increased epidemic growth relative to earlier circulating variants, has created a need to understand the drivers of such growth. However, both pathogen biology and changing host characteristics-such as varying levels of immunity-can combine to influence replication and transmission of SARS-CoV-2 within and between hosts. Disentangling the role of variant and host in individual-level viral shedding of VOCs is essential to inform Coronavirus Disease 2019 (COVID-19) planning and response and interpret past epidemic trends. Using data from a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening, we developed a Bayesian hierarchical model to reconstruct individual-level viral kinetics and estimate how different factors shaped viral dynamics, measured by PCR cycle threshold (Ct) values over time. Jointly accounting for both interindividual variation in Ct values and complex host characteristics-such as vaccination status, exposure history, and age-we found that age and number of prior exposures had a strong influence on peak viral replication. Older individuals and those who had at least 5 prior antigen exposures to vaccination and/or infection typically had much lower levels of shedding. Moreover, we found evidence of a correlation between the speed of early shedding and duration of incubation period when comparing different VOCs and age groups. Our findings illustrate the value of linking information on participant characteristics, symptom profile and infecting variant with prospective PCR sampling, and the importance of accounting for increasingly complex population exposure landscapes when analysing the viral kinetics of VOCs. Trial Registration: The Legacy study is a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening for SARS-CoV-2 at University College London Hospitals or at the Francis Crick Institute (NCT04750356) (22,23). The Legacy study was approved by London Camden and Kings Cross Health Research Authority Research and Ethics committee (IRAS number 286469). The Legacy study was approved by London Camden and Kings Cross Health Research Authority Research and Ethics committee (IRAS number 286469) and is sponsored by University College London Hospitals. Written consent was given by all participants.

Xrn2 accelerates termination by RNA polymerase II, which is underpinned by CPSF73 activity.

Termination is a ubiquitous phase in every transcription cycle but is incompletely understood and a subject of debate. We used gene editing as a new approach to address its mechanism through engineered conditional depletion of the 5' → 3' exonuclease Xrn2 or the polyadenylation signal (PAS) endonuclease CPSF73 (cleavage and polyadenylation specificity factor 73). The ability to rapidly control Xrn2 reveals a clear and general role for it in cotranscriptional degradation of 3' flanking region RNA and transcriptional termination. This defect is characterized genome-wide at high resolution using mammalian native elongating transcript sequencing (mNET-seq). An Xrn2 effect on termination requires prior RNA cleavage, and we provide evidence for this by showing that catalytically inactive CPSF73 cannot restore termination to cells lacking functional CPSF73. Notably, Xrn2 plays no significant role in either Histone or small nuclear RNA (snRNA) gene termination even though both RNA classes undergo 3' end cleavage. In sum, efficient termination on most protein-coding genes involves CPSF73-mediated RNA cleavage and cotranscriptional degradation of polymerase-associated RNA by Xrn2. However, as CPSF73 loss caused more extensive readthrough transcription than Xrn2 elimination, it likely plays a more underpinning role in termination.

The Adjuvant Combination of dmLT and Monophosphoryl Lipid A Activates the Canonical, Nonpyroptotic NLRP3 Inflammasome in Dendritic Cells and Significantly Interacts to Expand Antigen-Specific CD4 T Cells.

Adjuvants are often essential additions to vaccines that enhance the activation of innate immune cells, leading to more potent and protective T and B cell responses. Only a few vaccine adjuvants are currently used in approved vaccine formulations in the United States. Combinations of one or more adjuvants have the potential to increase the efficacy of existing and next-generation vaccines. In this study, we investigated how the nontoxic double mutant Escherichia coli heat-labile toxin R192G/L211A (dmLT), when combined with the TLR4 agonist monophosphoryl lipid A (MPL-A), impacted innate and adaptive immune responses to vaccination in mice. We found that the combination of dmLT and MPL-A induced an expansion of Ag-specific, multifaceted Th1/2/17 CD4 T cells higher than that explained by adding responses to either adjuvant alone. Furthermore, we observed more robust activation of primary mouse bone marrow-derived dendritic cells in the combination adjuvant-treated group via engagement of the canonical NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome complex. This was marked by a multiplicative increase in the secretion of active IL-1ß that was independent of classical gasdermin D-mediated pyroptosis. Moreover, the combination adjuvant increased the production of the secondary messengers cAMP and PGE2 in dendritic cells. These results demonstrate how certain adjuvant combinations could be used to potentiate better vaccine responses to combat a variety of pathogens.

Prognostic performance of non-invasive tests for portal hypertension is comparable to that of hepatic venous pressure gradient.

BACKGROUND & AIMS: Non-invasive tests to assess the probability of clinically significant portal hypertension (CSPH) - including the ANTICIPATE±NASH models based on liver stiffness measurement and platelet count±BMI, and the von Willebrand factor antigen to platelet count ratio (VITRO) - have fundamentally changed the management of compensated advanced chronic liver disease (cACLD). However, their prognostic utility has not been compared head-to-head to the gold standard for prognostication in cACLD, i.e. the hepatic venous pressure gradient (HVPG). METHODS: Patients with cACLD (liver stiffness measurement ≥10 kPa) who underwent advanced characterization via same-day HVPG/non-invasive test assessment from 2007-2022 were retrospectively included. Long-term follow-up data on hepatic decompensation was recorded. RESULTS: Four hundred and twenty patients with cACLD of varying etiologies, with a CSPH prevalence of 67.6%, were included. The cumulative incidence of hepatic decompensation at 1 and 2 years was 4.7% and 8.0%, respectively. HVPG, VITRO, and ANTICIPATE±NASH-CSPH-probability showed similar time-dependent prognostic value (AUROCs 0.683-0.811 at 1 year and 0.699-0.801 at 2 years). In competing risk analyses adjusted for MELD score and albumin, HVPG (adjusted subdistribution hazard ratio [aSHR] 1.099 [95% CI 1.054-1.150] per mmHg; p <0.001), or VITRO (aSHR 1.134 [95% CI 1.062-1.211] per unit; p <0.001), or ANTICIPATE±NASH-CSPH-probability (aSHR 1.232 [95% CI 1.094-1.387] per 10%; p <0.001) all predicted first decompensation during follow-up. Previously proposed cut-offs (HVPG ≥10 mmHg vs. <10 mmHg, VITRO ≥2.5 vs. <2.5, and ANTICIPATE-CSPH probability ≥60% vs. <60%) all accurately discriminated between patients at negligible risk and those at substantial risk of hepatic decompensation. CONCLUSIONS: The prognostic performance of ANTICIPATE±NASH-CSPH-probability and VITRO is comparable to that of HVPG, supporting their utility for identifying patients who may benefit from medical therapies to prevent first hepatic decompensation. IMPACT AND IMPLICATIONS: Non-invasive tests have revolutionized the diagnosis and management of clinically significant portal hypertension in patients with compensated advanced chronic liver disease (cACLD). However, limited data exists regarding the prognostic utility of non-invasive tests in direct comparison to the gold standard for prognostication in cACLD, i.e. the hepatic venous pressure gradient. In our study including 420 patients with cACLD, the ANTICIPATE±NASH model and VITRO yielded similar AUROCs to hepatic venous pressure gradient for hepatic decompensation within 1 to 2 years. Thus, non-invasive tests should be applied and updated in yearly intervals in clinical routine to identify patients at short-term risk, thereby identifying patients who may benefit from treatment aimed at preventing hepatic decompensation.

Validation of Baveno VII criteria and other non-invasive diagnostic algorithms for clinically significant portal hypertension in hepatitis delta.

BACKGROUND & AIMS: Non-invasive tests (NITs) for clinically significant portal hypertension (CSPH) require validation in patients with hepatitis D virus (HDV)-related compensated advanced chronic liver disease (cACLD). Therefore, we aimed to validate existing NIT algorithms for CSPH in this context. METHODS: Patients with HDV-cACLD (LSM ≥10 kPa or histological METAVIR F3/F4 fibrosis) who underwent paired HVPG and NIT assessment at Medical University of Vienna or Hannover Medical School between 2013 and 2023 were retrospectively included. Liver stiffness measurement (LSM), von Willebrand factor to platelet count ratio (VITRO), and spleen stiffness measurement (SSM) were assessed. Individual CSPH risk was calculated according to previously published models (ANTICIPATE, 3P/5P). The diagnostic performance of Baveno VII criteria and refined algorithms (Baveno VII-VITRO, Baveno VII-SSM) was evaluated. The prognostic utility of NITs was investigated in the main cohort and an independent, multicenter, validation cohort. RESULTS: Fifty-one patients (HVPG ≥10 mmHg/CSPH prevalence: 62.7%, varices: 42.2%) were included. Patients with CSPH had significantly higher LSM (25.8 [17.2-31.0] vs. 14.0 [10.5-19.8] kPa; p <0.001), VITRO (n = 31, 3.5 [2.7-4.5] vs. 1.3 [0.6-2.0] %/[G/L]; p <0.001), and SSM (n = 20, 53.8 [41.7-75.5] vs. 24.0 [17.0-33.9] kPa; p <0.001). Composite CSPH risk models yielded excellent AUROCs (ANTICIPATE: 0.885, 3P: 0.903, 5P: 0.912). Baveno VII criteria ruled out CSPH with 100% sensitivity and ruled in CSPH with 84.2% specificity. The Baveno VII 'grey zone' (41.1%) was significantly reduced by Baveno VII-VITRO or Baveno VII-SSM algorithms, which maintained diagnostic accuracy. Hepatic decompensation within 2 years only occurred in patients who had CSPH or met Baveno VII rule-in criteria. The prognostic value of NITs was confirmed in the validation cohort comprising 92 patients. CONCLUSIONS: Standalone and composite NIT/diagnostic algorithms are useful for CSPH diagnosis in patients with HDV-cACLD. Thus, NITs may be applied to identify and prioritize patients with CSPH for novel antiviral treatments against chronic hepatitis D. IMPACT AND IMPLICATIONS: Non-invasive tests (NITs) for clinically significant portal hypertension (CSPH) have been developed to identify patients with compensated advanced chronic liver disease (cACLD) at risk of decompensation, but conflicting data has been published regarding the accuracy of liver stiffness measurement (LSM) for the staging of fibrosis in patients infected with hepatitis D virus (HDV). In our study, including 51 patients with HDV-cACLD, LSM- and lab-based NITs yielded high AUROCs for CSPH. Moreover, only patients with CSPH or high non-invasively assessed CSPH risk were at risk of decompensation within 2 years, with the prognostic value of NITs confirmed in a validation cohort. Thus, NITs should be applied and updated in yearly intervals in clinical routine to identify patients with HDV-cACLD at short-term risk of clinical events; NITs may also guide prioritization for novel antiviral treatment options.

Post-treatment LSM rather than change during treatment predicts decompensation in patients with cACLD after HCV cure.

BACKGROUND & AIMS: Baveno VII has defined a clinically significant (i.e., prognostically meaningful) decrease in liver stiffness measurement (LSM) in cACLD as a decrease of ≥20% associated with a final LSM <20 kPa or any decrease to <10 kPa. However, these rules have not yet been validated against direct clinical endpoints. METHODS: We retrospectively analysed patients with cACLD (LSM ≥10 kPa) with paired liver stiffness measurement (LSM) before (BL) and after (FU) HCV cure by interferon-free therapies from 15 European centres. The cumulative incidence of hepatic decompensation was compared according to these criteria, considering hepatocellular carcinoma and non-liver-related death as competing risks. RESULTS: A total of 2,335 patients followed for a median of 6 years were analysed. Median BL-LSM was 16.6 kPa with 37.1% having ≥20 kPa. After HCV cure, FU-LSM decreased to a median of 10.9 kPa (<10 kPa: 1,002 [42.9%], ≥20 kPa: 465 [19.9%]) translating into a median LSM change of -5.3 (-8.8 to -2.4) kPa corresponding to -33.9 (-48.0 to -15.9) %. Patients achieving a clinically significant decrease (65.4%) had a significantly lower risk of hepatic decompensation (subdistribution hazard ratio: 0.12, 95% CI 0.04-0.35, p <0.001). However, these risk differences were primarily driven by a negligible risk in patients with FU-LSM <10 kPa (5-year cumulative incidence: 0.3%) compared to a high risk in patients with FU-LSM ≥20 kPa (16.6%). Patients with FU-LSM 10-19.9 kPa (37.4%) also had a low risk of hepatic decompensation (5-year cumulative incidence: 1.7%), and importantly, the risk of hepatic decompensation did not differ between those with/without an LSM decrease of ≥20% (p = 0.550). CONCLUSIONS: FU-LSM is key for risk stratification after HCV cure and should guide clinical decision making. LSM dynamics do not hold significant prognostic information in patients with FU-LSM 10-19.9 kPa, and thus, their consideration is not of sufficient incremental value in the specific context of HCV cure. IMPACT AND IMPLICATIONS: Liver stiffness measurement (LSM) is increasingly applied as a prognostic biomarker and commonly decreases in patients with compensated advanced chronic liver disease achieving HCV cure. Although Baveno VII proposed criteria for a clinically significant decrease, little is known about the prognostic utility of LSM dynamics (changes through antiviral therapy). Interestingly, in those with a post-treatment LSM of 10-19.9 kPa, LSM dynamics did not provide incremental information, arguing against the consideration of LSM dynamics as prognostic criteria. Thus, post-treatment LSM should guide the management of patients with compensated advanced chronic liver disease achieving HCV cure.

Dynamics in Liver Stiffness Measurements Predict Outcomes in Advanced Chronic Liver Disease.

BACKGROUND & AIMS: Liver stiffness measurements (LSMs) provide an opportunity to monitor liver disease progression and regression noninvasively. We aimed to determine the prognostic relevance of LSM dynamics over time for liver-related events and death in patients with chronic liver disease. METHODS: Patients with chronic liver disease undergoing 2 or more reliable LSMs at least 180 days apart were included in this retrospective cohort study and stratified at baseline (BL) as nonadvanced chronic liver disease (non-ACLD, BL-LSM < 10 kPa), compensated ACLD (cACLD; BL-LSM ≥ 10 kPa), and decompensated ACLD. Data on all consecutive LSMs and clinical outcomes were collected. RESULTS: There were 2508 patients with 8561 reliable LSMs (3 per patient; interquartile range, 2-4) included: 1647 (65.7%) with non-ACLD, 757 (30.2%) with cACLD, and 104 (4.1%) with decompensated ACLD. Seven non-ACLD patients (0.4%) and 83 patients with cACLD (10.9%) developed hepatic decompensation (median follow-up, 71 months). A 20% increase in LSM at any time was associated with an approximately 50% increased risk of hepatic decompensation (hazard ratio, 1.58; 95% CI, 1.41-1.79; P < .001) and liver-related death (hazard ratio, 1.45; 95% CI, 1.28-1.68; P < .001) in patients with cACLD. LSM dynamics yielded a high accuracy to predict hepatic decompensation in the following 12 months (area under the receiver operating characteristics curve = 0.933). The performance of LSM dynamics was numerically better than dynamics in Fibrosis-4 score (0.873), Model for End-Stage Liver Disease (0.835), and single time-point LSM (BL-LSM: 0.846; second LSM: 0.880). Any LSM decrease to <20 kPa identified patients with cACLD with a substantially lower risk of hepatic decompensation (hazard ratio, 0.13; 95% CI, 0.07-0.24). If reliable, LSM also confers prognostic information in decompensated ACLD. CONCLUSIONS: Repeating LSM enables an individual and updated risk assessment for decompensation and liver-related mortality in ACLD.

Etiological cure prevents further decompensation and mortality in patients with cirrhosis with ascites as the single first decompensating event.

BACKGROUND AND AIMS: Removal/suppression of the primary etiological factor reduces the risk of decompensation and mortality in compensated cirrhosis. However, in decompensated cirrhosis, the impact of etiologic treatment is less predictable. We aimed to evaluate the impact of etiological treatment in patients with cirrhosis who developed ascites as single index decompensating event. APPROACH AND RESULTS: Patients with cirrhosis and ascites as single first decompensation event were included and followed until death, liver transplantation, or Q3/2021. The etiology was considered "cured" (alcohol abstinence, hepatitis C cure, and hepatitis B suppression) versus "controlled" (partial removal of etiologic factors) versus "uncontrolled." A total of 622 patients were included in the study. Etiology was "cured" in 146 patients (24%), "controlled" in 170 (27%), and "uncontrolled" in 306 (49%). During follow-up, 350 patients (56%) developed further decompensation. In multivariable analysis (adjusted for age, sex, varices, etiology, Child-Pugh class, creatinine, sodium, and era of decompensation), etiological cure was independently associated with a lower risk of further decompensation (HR: 0.46; p = 0.001). During follow-up, 250 patients (40.2%) died, while 104 (16.7%) underwent LT. In multivariable analysis, etiological cure was independently associated with a lower mortality risk (HR: 0.35, p < 0.001). CONCLUSIONS: In patients with cirrhosis and ascites as single first decompensating event, the cure of liver disease etiology represents a main treatment goal since this translates into considerably lower risks of further decompensation and mortality.

Examination of the PET in vivo generator 134Ce as a theranostic match for 225Ac.

PURPOSE: The radionuclide pair cerium-134/lanthanum-134 (134Ce/134La) was recently proposed as a suitable diagnostic counterpart for the therapeutic alpha-emitter actinium-225 (225Ac). The unique properties of 134Ce offer perspectives for developing innovative in vivo investigations that are not possible with 225Ac. In this work, 225Ac- and 134Ce-labelled tracers were directly compared using internalizing and slow-internalizing cancer models to evaluate their in vivo comparability, progeny meandering, and potential as a matched theranostic pair for clinical translation. Despite being an excellent chemical match, 134Ce/134La has limitations to the setting of quantitative positron emission tomography imaging. METHODS: The precursor PSMA-617 and a macropa-based tetrazine-conjugate (mcp-PEG8-Tz) were radiolabelled with 225Ac or 134Ce and compared in vitro and in vivo using standard (radio)chemical methods. Employing biodistribution studies and positron emission tomography (PET) imaging in athymic nude mice, the radiolabelled PSMA-617 tracers were evaluated in a PC3/PIP (PC3 engineered to express a high level of prostate-specific membrane antigen) prostate cancer mouse model. The 225Ac and 134Ce-labelled mcp-PEG8-Tz were investigated in a BxPC-3 pancreatic tumour model harnessing the pretargeting strategy based on a trans-cyclooctene-modified 5B1 monoclonal antibody. RESULTS: In vitro and in vivo studies with both 225Ac and 134Ce-labelled tracers led to comparable results, confirming the matching pharmacokinetics of this theranostic pair. However, PET imaging of the 134Ce-labelled precursors indicated that quantification is highly dependent on tracer internalization due to the redistribution of 134Ce's PET-compatible daughter 134La. Consequently, radiotracers based on internalizing vectors like PSMA-617 are suited for this theranostic pair, while slow-internalizing 225Ac-labelled tracers are not quantitatively represented by 134Ce PET imaging. CONCLUSION: When employing slow-internalizing vectors, 134Ce might not be an ideal match for 225Ac due to the underestimation of tumour uptake caused by the in vivo redistribution of 134La. However, this same characteristic makes it possible to estimate the redistribution of 225Ac's progeny noninvasively. In future studies, this unique PET in vivo generator will further be harnessed to study tracer internalization, trafficking of receptors, and the progression of the tumour microenvironment.

High histamine levels are associated with acute-on-chronic liver failure and liver-related death in patients with advanced chronic liver disease.

BACKGROUND AND AIMS: The role of histamine in advanced chronic liver disease (ACLD) is poorly understood. We investigated plasma histamine levels across ACLD stages and their prognostic value. METHODS: We included patients with evidence of ACLD, defined by portal hypertension (hepatic venous pressure gradient [HVPG] ≥6 mmHg) and/or a liver stiffness measurement by transient elastography ≥10 kPa, who underwent HVPG measurement between 2017 and 2020. Acute-on-chronic liver failure (ACLF) and/or liver-related death were defined as composite endpoint. RESULTS: Of 251 patients, 82.5% had clinically significant portal hypertension (median HVPG: 17 mmHg [interquartile range (IQR) 12-21]) and 135 patients (53.8%) were decompensated at baseline. Median plasma histamine was 8.5 nmol/L (IQR: 6.4-11.5), 37.1% of patients showed elevated values (>9.9 nmol/L). Histamine levels did not differ significantly across Child-Turcotte-Pugh (CTP) stages nor strata of model for end-stage liver disease (MELD) or HVPG. Histamine levels correlated with markers of circulatory dysfunction (i.e. sodium, renin and aldosterone). During a median follow-up of 29.2 months, 68 patients developed ACLF or liver-related death. In univariate as well as in multivariate analysis (adjusting for age, sex, HVPG as well as either MELD, clinical stage, and serum albumin or CTP and serum sodium), elevated histamine levels remained associated with the composite endpoint. CTP-based multivariate model adjusted sub-distribution hazard ratio (asHR): 1.010 (95% CI: 1.004-1.021), p < .001; MELD-based multivariate model asHR: 1.030 (95% CI: 1.017-1.040), p < .001. CONCLUSION: High levels of histamine were linked to circulatory dysfunction in ACLD patients and independently associated with increased risks of ACLF or liver-related death. Further mechanistic studies on the link between histamine signalling and development of hyperdynamic circulation and ACLF are warranted.

A systematic PCR record-based re-call of HCV-RNA-positive people enables re-linkage to care and HCV elimination in Austria - The ELIMINATE project.

BACKGROUND AND AIMS: Identification of people living with hepatitis C virus (HCV) via readily available laboratory records could be a key strategy for macro-elimination, aligning with the WHO elimination goal. Therefore, the ELIMINATE(ELIMINation of HCV in AusTria East) project aimed to systematically re-link people with a 'last-positive' HCV-RNA PCR record to care. METHODS: In 10 major liver centres in Eastern Austria, a systematic readout of 'last-positive' HCV-RNA PCR test records obtained between 2008 and 2020 were conducted and linked to available patient contact data. Between 2020 and 2023, individuals were contacted first by phone, then by letter, to inform them about the availability of effective direct-acting antiviral (DAA) treatment and invite them for pre-treatment evaluation. RESULTS: The overall cohort of last-positive HCV+ individuals included 5695 subjects (62.5% males, mean age 57.3 ± 17.3 years); of note, 1931 (34%) of them had died and 759 (13%) individuals had no valid contact information. Of the remaining 3005 individuals, 1171 (40.0%) had already achieved sustained virological response (SVR) at the time of re-call. We successfully reached 617 (20.5%), of whom 417 (67.6%) attended their pre-treatment visit, and 397 (64.3%) commenced DAA-therapy. HCV cure has been confirmed in 326 individuals, corresponding to an SVR rate of 82.1%. CONCLUSION: The ELIMINATE project identified 5695 people living with HCV who were 'lost to care' despite documented HCV viraemia. While invalid contact data were an evident barrier to HCV elimination, premature deaths among the cohort underscored the severity of untreated HCV. The implementation of a systematic HCV-RNA PCR recorded-based re-call workflow represents an effective strategy supporting the WHO goal of HCV elimination.

SARS-CoV-2 Antibody Response Is Associated with Age and Body Mass Index in Convalescent Outpatients.

COVID-19 has had an unprecedented global impact on human health. Understanding the Ab memory responses to infection is one tool needed to effectively control the pandemic. Among 173 outpatients who had virologically confirmed SARS-CoV-2 infection, we evaluated serum Ab concentrations, microneutralization activity, and enumerated SARS-CoV-2-specific B cells in convalescent human blood specimens. Serum Ab concentrations were variable, allowing for stratification of the cohort into high and low responders. Neither participant sex, the timing of blood sampling following the onset of illness, nor the number of SARS-CoV-2 spike protein-specific B cells correlated with serum Ab concentration. Serum Ab concentration was positively associated with microneutralization activity and participant age, with participants under the age of 30 showing the lowest Ab level. These data suggest that young adult outpatients did not generate as robust Ab memory, compared with older adults. Body mass index was also positively correlated with serum Ab levels. Multivariate analyses showed that participant age and body mass index were independently associated with Ab levels. These findings have direct implications for public health policy and current vaccine efforts. Knowledge gained regarding Ab memory following infection will inform the need for vaccination in those previously infected and allow for a better approximation of population-wide protective immunity.

RNA Polymerase Pausing during Initial Transcription.

In bacteria, RNA polymerase (RNAP) initiates transcription by synthesizing short transcripts that are either released or extended to allow RNAP to escape from the promoter. The mechanism of initial transcription is unclear due to the presence of transient intermediates and molecular heterogeneity. Here, we studied initial transcription on a lac promoter using single-molecule fluorescence observations of DNA scrunching on immobilized transcription complexes. Our work revealed a long pause ("initiation pause," ∼20 s) after synthesis of a 6-mer RNA; such pauses can serve as regulatory checkpoints. Region sigma 3.2, which contains a loop blocking the RNA exit channel, was a major pausing determinant. We also obtained evidence for RNA backtracking during abortive initial transcription and for additional pausing prior to escape. We summarized our work in a model for initial transcription, in which pausing is controlled by a complex set of determinants that modulate the transition from a 6- to a 7-nt RNA.

Scenario Decision-Making About Plasma and Platelet Transfusion for Intracranial Monitor Placement: Cross-Sectional Survey of Pediatric Intensivists and Neurosurgeons.

OBJECTIVES: To report pediatric intensivists' and pediatric neurosurgeons' responses to case-based scenarios about plasma and platelet transfusions before intracranial pressure (ICP) monitor placement in children with severe traumatic brain injury (TBI). DESIGN: Cross-sectional, electronic survey to evaluate reported plasma and platelet transfusion decisions in eight scenarios of TBI in which ICP monitor placement was indicated. SETTING: Survey administered through the Pediatric Acute Lung Injury and Sepsis Investigators and the American Association of Neurologic Surgeons. SUBJECTS: Pediatric intensivists and pediatric neurosurgeons. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 184 participants responded (85 identified as pediatric intensivists and 54 as pediatric neurosurgeons). In all eight scenarios, the majority of respondents reported that they would base their decision-making about plasma transfusion on international normalized ratio (INR) alone (60-69%), or platelet transfusion on platelet count alone (83-86%). Pediatric intensivists, as opposed to pediatric neurosurgeons, more frequently reported that they would have used viscoelastic testing in their consideration of plasma transfusion (32% vs. 7%, p < 0.001), as well as to guide platelet transfusions (29 vs. 8%, p < 0.001), for the case-based scenarios. For all relevant case-based scenarios, pediatric neurosurgeons in comparison with pediatric reported that they would use a lower median (interquartile range [IQR]) INR threshold for plasma transfusion (1.5 [IQR 1.4-1.7] vs. 2.0 [IQR 1.5-2.0], p < 0.001). Overall, in all respondents, the reported median platelet count threshold for platelet transfusion in the case-based scenario was 100 (IQR 50-100) ×10 9 /L, with no difference between specialties. CONCLUSIONS: Despite little evidence showing efficacy, when we tested specialists' decision-making, we found that they reported using INR and platelet count in pediatric case-based scenarios of TBI undergoing ICP monitor placement. We also found that pediatric intensivists and pediatric neurosurgeons had differences in decision-making about the scenarios.

Anterior cervical discectomy and fusion for the treatment of pediatric Hirayama disease.

PURPOSE: Hirayama disease, a rare cervical myelopathy in children and young adults, leads to progressive upper limb weakness and muscle loss. Non-invasive external cervical orthosis has been shown to prevent further neurologic decline; however, this treatment modality has not been successful at restoring neurologic and motor function, especially in long standing cases with significant weakness. The pathophysiology remains not entirely understood, complicating standardized operative guidelines; however, some studies report favorable outcomes with internal fixation. We report a successful surgically treated case of pediatric Hirayama disease, supplemented by a systematic review and collation of reported cases in the literature. METHODS: A review of the literature was performed by searching PubMed, Embase, and Web of Science. Full-length articles were included if they reported clinical data regarding the treatment of at least one patient with Hirayama disease and the neurologic outcome of that treatment. Articles were excluded if they did not provide information on treatment outcomes, were abstract-only publications, or were published in languages other than English. RESULTS: Of the fifteen articles reviewed, 63 patients were described, with 59 undergoing surgery. This encompassed both anterior and posterior spinal procedures and 1 hand tendon transfer. Fifty-five patients, including one from our institution, showed improvement post-treatment. Eleven of these patients were under 18 years old. CONCLUSION: Hirayama disease is an infrequent yet impactful cervical myelopathy with limited high-quality evidence available for optimal treatment. The current literature supports surgical decompression and stabilization as promising interventions. However, comprehensive research is crucial for evolving diagnosis and treatment paradigms.

Understanding confounding factors allows for accurate interpretation of liver stiffness measurements by ElastQ, a novel 2D shear wave elastography technique.

PURPOSE: Liver stiffness measurement (LSM) using vibration-controlled transient elastography (VCTE) or two-dimensional shear wave elastography (2D-SWE) is recommended to assess the risk of liver fibrosis and advanced chronic liver disease. Even though both techniques measure liver stiffness, their numerical results often diverge. Confounders and reliability criteria for 2D-SWE have not been systematically investigated. MATERIALS AND METHODS: We prospectively recruited participants with paired LSM by VCTE and the novel 2D-SWE technique ElastQ (Philips) in three European tertiary centers. The following parameters were recorded: sex, age, body mass index (BMI), etiology, laboratory markers of liver damage and function, as well as cholestasis, LSM by VCTE and controlled attenuation parameter (CAP), interquartile range (IQR)/median for VCTE-LSM and ElastQ-LSM, and the skin-to-liver capsule distance. RESULTS: We included 840 participants: 447 (53.2%) males; median age 57.0 [IQR:19.0] years; median BMI 25.4 [6.0] kg/m2; median VCTE-LSM 7.25 [9.2] kPa; median ElastQ-LSM 6.7 [5.4] kPa. On uni- and multivariable modeling (adjusted for LSM), we found that the discrepancy increased with liver stiffness and markers of disease severity. Skin-to-liver capsule distance and BMI affected VCTE-LSM more compared to ElastQ-LSM and significantly increased the discordance between the two measurements. CONCLUSION: The discrepancy of ElastQ-LSM to VCTE-LSM increases with liver stiffness and disease severity. BMI and skin-to-liver capsule distance increase the discrepancy between VCTE- and ElastQ-LSM but affect ElastQ-LSM less. The quality criterion IQR/median ≤ 30% indicates reliable ElastQ-LSM.

Alcohol Abstinence Improves Prognosis Across All Stages of Portal Hypertension in Alcohol-Related Cirrhosis.

BACKGROUND AND AIMS: Alcohol-related liver disease is a leading cause of liver-related mortality. The effect of alcohol abstinence on the natural history of alcohol-related cirrhosis across distinct stages of portal hypertension has not been thoroughly investigated. In this study, we assessed the clinical implications of abstinence in patients with alcohol-related cirrhosis and clinically significant portal hypertension. METHODS: Alcohol abstinence, hepatic decompensation, and mortality were assessed in patients with alcohol-related cirrhosis who underwent a baseline hepatic venous pressure gradient (HVPG) measurement and were diagnosed with clinically significant portal hypertension (HVPG ≥10 mm Hg). RESULTS: A total of 320 patients with alcohol-related cirrhosis (median age: 57 [interquartile range (IQR), 49.7-63.1] years; 75.6% male; 87.5% decompensated) and a median HVPG of 20 (IQR, 17-23) mm Hg were followed up for a median of 36 (IQR, 14-80) months. Overall, 241 (75.3%) patients remained abstinent, while 79 (24.7%) patients had active alcohol consumption. Alcohol abstinence was linked to a significantly reduced risk of hepatic decompensation (adjusted hazard ratio [aHR], 0.391; P < .001), as well as liver-related (aHR, 0.428; P < .001) and all-cause (aHR, 0.453; P < .001) mortality, after adjusting for baseline HVPG, MELD, and previous decompensation. Importantly, alcohol abstinence significantly reduced the cumulative incidence of hepatic decompensation in both groups with HVPG 10-19 mm Hg (P < .001) and HVPG ≥20 mm Hg (P = .002). The 3-year decompensation probability was 32.4% vs 60.0% in HVPG 10-19 mm Hg and 57.5% vs 82.6% in HVPG ≥20 mm Hg for abstinent patients vs active drinkers, respectively. CONCLUSIONS: Alcohol abstinence improves prognosis across all stages of portal hypertension in alcohol-related cirrhosis, including in patients who have already progressed to high-risk portal hypertension. (ClinicalTrials.gov, Number: NCT03267615).

Carvedilol Achieves Higher Hemodynamic Response and Lower Rebleeding Rates Than Propranolol in Secondary Prophylaxis.

BACKGROUND & AIMS: Carvedilol induces stronger decreases in hepatic venous pressure gradient (HVPG) than conventional nonselective ß-blockers (ie, propranolol). Limited data exist on the efficacy of carvedilol in secondary prophylaxis of variceal bleeding. METHODS: Patients undergoing paired HVPG measurements for guiding secondary prophylaxis with either carvedilol or propranolol were included in this retrospective analysis. All patients also underwent band ligation. Changes in HVPG and systemic hemodynamics were compared between the 2 groups. Long-term follow-up data on rebleeding, acute kidney injury, nonbleeding decompensation, and liver-related death were analyzed applying competing risk regression. RESULTS: Eighty-seven patients (carvedilol/propranolol, n = 45/42) were included in our study. The median baseline HVPG was 21 mm Hg (interquartile range, 18-24 mm Hg), and 39.1%/48.3%/12.6% had Child-Turcotte-Pugh A/B/C cirrhosis, respectively. Upon nonselective ß-blocker initiation, HVPG decreased more strongly in carvedilol users (median relative decrease, -20% [interquartile range: -29% to -10%] vs -11% [-22% to -5%] for propranolol; P = .027), who also achieved chronic HVPG response more often (53.3% vs 28.6%; P = .034). Cumulative incidences for rebleeding (Gray test, P = .027) and liver-related death (P = .036) were significantly lower in patients taking carvedilol compared with propranolol. Notably, ascites development/worsening also was observed less commonly in carvedilol patients (P = .012). Meanwhile, acute kidney injury rates did not differ between the 2 groups (P = .255). Stratifying patients by HVPG response status yielded similar results. The prognostic value of carvedilol intake was confirmed in competing risk regression models. CONCLUSIONS: Carvedilol induces more marked reductions in HVPG than propranolol in secondary prophylaxis of variceal bleeding, and thus is associated with lower rates of rebleeding, liver-related death, and further nonbleeding decompensation.

The Sequential Application of Baveno VII Criteria and VITRO Score Improves Diagnosis of Clinically Significant Portal Hypertension.

BACKGROUND & AIMS: Baveno VII proposed liver stiffness measurement (LSM)/platelet count (PLT)-based criteria ('ruled out,' LSM ≤15 kPa plus PLT ≥150 G/L; 'ruled in': LSM ≥25 kPa) for clinically significant portal hypertension (CSPH) in compensated advanced chronic liver disease (cACLD). However, a substantial proportion of patients remains 'unclassified.' METHODS: Patients with evidence of cACLD (LSM ≥10 kPa) undergoing hepatic venous pressure gradient (HVPG) measurement at the Vienna General Hospital 2004 to 2021 (derivation [2004-2016], n = 221; validation [2017-2021], n = 81) were included. The performance of noninvasive tests (NITs) including von Willebrand factor antigen to PLT ratio (VITRO) for the detection of CSPH (HVPG ≥10 mmHg) were evaluated. RESULTS: Overall, viral hepatitis was the predominant (50.7%) etiology, followed by alcoholic liver disease (15.2%) and nonalcoholic steatohepatitis (13.2%); CSPH prevalence was 62.3%. In the derivation cohort, 45.7% were 'unclassified' according to Baveno VII criteria; in this group, VITRO showed an excellent diagnostic performance for the detection of CSPH (area under the receiver operating curve, 0.909; 95% confidence interval, 0.823-0.965). VITRO ≤1.5 and ≥2.5 ruled out (sensitivity, 97.7%; negative predictive value, 97.5%) and ruled in (specificity, 94.7%; positive predictive value, 91.2%), respectively, CSPH in patients who were 'unclassifiable' by Baveno VII criteria. The application of a sequential Baveno VII-VITRO algorithm reallocated 73% and 70% of 'unclassified' patients to the 'ruled in' and 'ruled out' group, respectively, while maintaining high sensitivity and negative predictive value and specificity and positive predictive value in the derivation and validation cohort, respectively. No patient allocated to the 'CSPH ruled out' group by the Baveno VII-VITRO algorithm developed decompensation within 5 years, whereas 5-year decompensation rates were negligible (4%) and substantial (23.9%) among 'unclassified' and 'CSPH ruled in' patients, respectively. CONCLUSIONS: The sequential application of VITRO in patients with cACLD who were 'unclassifiable' with regard to CSPH by Baveno VII criteria substantially decreased the number of 'unclassifiable' patients to <15% and refined prognostication.