Liver-Resident Bystander CD8+ T Cells Contribute to Liver Disease Pathogenesis in Chronic Hepatitis D Virus Infection.

BACKGROUND & AIMS: The hepatitis D virus (HDV) causes the most severe form of chronic hepatitis, often progressing to cirrhosis within 5 to 10 years. There is no curative treatment, and the mechanisms underlying the accelerated liver disease progression are unknown. METHODS: Innate and adaptive immune responses were studied in blood and liver of 24 patients infected with HDV and 30 uninfected controls by multiparameter flow cytometry in correlation with disease severity and stage. RESULTS: The 2 main intrahepatic innate immune-cell populations, mucosal-associated invariant T cells and natural killer (NK) cells, were reduced in the livers of patients infected with HDV compared with those of uninfected controls but were more frequently activated in the liver compared with the blood. Most intrahepatic cluster of differentiation (CD) 8-positive (CD8+) T cells were memory cells or terminal effector memory cells, and most of the activated and degranulating (CD107a+) HDV-specific and total CD8+ T cells were liver-resident (CD69+C-X-C motif chemokine receptor 6+). Unsupervised analysis of flow cytometry data identified an activated, memory-like, tissue-resident HDV-specific CD8+ T-cell cluster with expression of innate-like NK protein 30 (NKp30) and NK group 2D (NKG2D) receptors. The size of this population correlated with liver enzyme activity (r = 1.0). NKp30 and NKG2D expression extended beyond the HDV-specific to the total intrahepatic CD8+ T-cell population, suggesting global bystander activation. This was supported by the correlations between (i) NKG2D expression with degranulation of intrahepatic CD8+ T cells, (ii) frequency of degranulating CD8+ T cells with liver enzyme activity and the aspartate aminotransferase-to-platelet ratio index score, and by the in vitro demonstration of cytokine-induced NKG2D-dependent cytotoxicity. CONCLUSION: Antigen-nonspecific activation of liver-resident CD8+ T cells may contribute to inflammation and disease stage in HDV infection.

Mucosal-Associated Invariant T Cells in Chronic Inflammatory Liver Disease.

The broadening field of microbiome research has led to a substantial reappraisal of the gut-liver axis and its role in chronic liver disease. The liver is a central immunologic organ that is continuously exposed to food and microbial-derived antigens from the gastrointestinal tract. Mucosal-associated invariant T (MAIT) cells are enriched in the human liver and can be activated by inflammatory cytokines and microbial antigens. In chronic inflammatory liver disease, MAIT cells are depleted suggesting an impaired MAIT cell-dependent protection against bacterial infections.

Intra-Hepatic Depletion of Mucosal-Associated Invariant T Cells in Hepatitis C Virus-Induced Liver Inflammation.

BACKGROUND & AIMS: Chronic hepatitis affects phenotypes of innate and adaptive immune cells. Mucosal-associated invariant T (MAIT) cells are enriched in the liver as compared with the blood, respond to intra-hepatic cytokines, and (via the semi-invariant T-cell receptor) to bacteria translocated from the gut. Little is known about the role of MAIT cells in livers of patients with chronic hepatitis C virus (HCV) infection and their fate after antiviral therapy. METHODS: We collected blood samples from 42 patients with chronic HCV infection who achieved a sustained virologic response after 12 weeks of treatment with sofosbuvir and velpatasvir. Mononuclear cells were isolated from blood before treatment, at weeks 4 and 12 during treatment, and 24 weeks after the end of treatment. Liver biopsies were collected from 37 of the patients prior to and at week 4 of treatment. Mononuclear cells from 56 blood donors and 10 livers that were not suitable for transplantation were used as controls. Liver samples were assessed histologically for inflammation and fibrosis. Mononuclear cells from liver and blood were studied by flow cytometry and analyzed for responses to cytokine and bacterial stimulation. RESULTS: The frequency of MAIT cells among T cells was significantly lower in blood and liver samples of patients with HCV infection than of controls (median, 1.31% vs 2.32% for blood samples, P = .0048; and median, 4.34% vs 13.40% for liver samples, P = .001). There was an inverse correlation between the frequency of MAIT cells in the liver and histologically determined levels of liver inflammation (r = -.5437, P = .0006) and fibrosis (r = -.5829, P = .0002). MAIT cells from the liver had higher levels of activation and cytotoxicity than MAIT cells from blood (P < .0001). Production of interferon gamma by MAIT cells was dependent on monocyte-derived interleukin 18, and was reduced in patients with HCV infection in response to T-cell receptor-mediated but not cytokine-mediated stimulation, as compared with controls. Anti-viral therapy rapidly decreased liver inflammation and MAIT cell activation and cytotoxicity, and increased the MAIT cell frequency among intra-hepatic but not blood T cells. The MAIT cell response to T-cell receptor-mediated stimulation did not change during the 12 weeks of antiviral therapy. CONCLUSIONS: In analyses of paired blood and liver samples from patients with chronic HCV infection before, during, and after antiviral therapy with sofosbuvir and velpatasvir, we found that intrahepatic MAIT cells are activated by monocyte-derived cytokines and depleted in HCV-induced liver inflammation.

Evaluation of domino liver transplantations in Germany.

A retrospective multicenter study has been conducted to evaluate domino liver transplantations (DLTs) in Germany. The study provides insight into survival and features having an impact on the assessment of neuropathy after DLT. In addition, a neurologic follow-up program with a scheme to estimate the likelihood of de novo amyloidosis is presented. A series of 61 DLTs at seven transplant centers in Germany was enrolled. The mean age of domino recipients at the time of transplantation was 58 years, 46 of them being men, and 15 being women. The median follow-up was 46 months. The overall 1-, 3-, and 5-year survival of domino recipients was 81.6%, 70.8% and 68.8%, respectively. Causes of death were primarily not related to familial amyloidosis. The main indication of DLT was hepatocellular carcinoma. Two of the reported domino recipients developed symptoms and signs of de novo amyloidosis within 10 years after transplantation. A total of 30 domino graft recipients (49.18%) presented with diabetes post transplantation. In conclusion, an advanced follow-up program is crucial to evaluate the risk of transmitting familial amyloidosis by DLT and to establish more strict selection criteria for domino recipients.

Immune checkpoint inhibitor-related liver toxicity.

Content available: Audio Recording.

Association of sarcopenia with survival in advanced NSCLC patients receiving concurrent immunotherapy and chemotherapy.

Background: Frailty, sarcopenia and malnutrition are powerful predictors of clinical outcomes that are not routinely measured in patients with non-small cell lung cancer (NSCLC). The primary aim of this study was to investigate the association of sarcopenia, determined by the psoas muscle index (PMI) with overall survival (OS) in patients with advanced NSCLC treated with concurrent immune checkpoint inhibitor (ICI) and chemotherapy (CTX). Methods: We retrospectively reviewed data from a cohort of patients with locally advanced or metastatic NSCLC who were treated between 2015 and 2021 at the University of Virginia Medical Center. The cross-sectional area of the psoas muscle was assessed on CT or PET/CT imaging prior to treatment initiation. Multivariate analysis was performed using Cox proportional hazards regression models. Results: A total of 92 patients (median age: 64 years, range 36-89 years), 48 (52.2%) men and 44 (47.8%) women, were included in the study. The median follow-up was 29.6 months. The median OS was 17.8 months. Sarcopenia, defined by a PMI below the 25th percentile, was associated with significantly lower OS (9.1 months in sarcopenic patients vs. 22.3 months in non-sarcopenic patients, P = 0.002). Multivariate analysis revealed that sarcopenia (HR 2.12, P = 0.0209), ECOG ≥ 2 (HR 2.88, P = 0.0027), prognostic nutritional index (HR 3.02, P = 0.0034) and the absence of immune related adverse events (HR 2.04, P = 0.0185) were independently associated with inferior OS. Conclusions: Sarcopenia is independently associated with poor OS in patients with advanced NSCLC undergoing concurrent ICI and CTX.

Vis-a-Vis: Visual Exploration of Visualization Source Code Evolution.

Developing an algorithm for a visualization prototype often involves the direct comparison of different development stages and design decisions, and even minor modifications may dramatically affect the results. While existing development tools provide visualizations for gaining general insight into performance and structural aspects of the source code, they neglect the central importance of result images unique to graphical algorithms. In this article, we present a novel approach that enables visualization programmers to simultaneously explore the evolution of their algorithm during the development phase together with its corresponding visual outcomes by providing an automatically updating meta visualization. Our interactive system allows for the direct comparison of all development states on both the visual and the source code level, by providing easy to use navigation and comparison tools. The on-the-fly construction of difference images, source code differences, and a visual representation of the source code structure further enhance the user's insight into the states' interconnected changes over time. Our solution is accessible via a web-based interface that provides GPU-accelerated live execution of C++ and GLSL code, as well as supporting a domain-specific programming language for scientific visualization.

SplitStreams: A Visual Metaphor for Evolving Hierarchies.

The visualization of hierarchically structured data over time is an ongoing challenge and several approaches exist trying to solve it. Techniques such as animated or juxtaposed tree visualizations are not capable of providing a good overview of the time series and lack expressiveness in conveying changes over time. Nested streamgraphs provide a better understanding of the data evolution, but lack the clear outline of hierarchical structures at a given timestep. Furthermore, these approaches are often limited to static hierarchies or exclude complex hierarchical changes in the data, limiting their use cases. We propose a novel visual metaphor capable of providing a static overview of all hierarchical changes over time, as well as clearly outlining the hierarchical structure at each individual time step. Our method allows for smooth transitions between treemaps and nested streamgraphs, enabling the exploration of the trade-off between dynamic behavior and hierarchical structure. As our technique handles topological changes of all types, it is suitable for a wide range of applications. We demonstrate the utility of our method on several use cases, evaluate it with a user study, and provide its full source code.

Step by Step: Managing the Complications of Cirrhosis.

According to the Centers for Disease Control and Prevention, chronic liver disease and cirrhosis is the 11th leading cause of death in the United States. Common causes of chronic liver disease include alcohol, viral hepatitis, and non-alcoholic steatohepatitis (NASH). Inflammation is a critical driver in the progression of liver disease to liver fibrosis and ultimately cirrhosis. While the severity of chronic liver disease extends over a continuum, the management is more easily differentiated between compensated and decompensated cirrhosis. In this review, we discuss pathophysiology, clinical features and management of common complications of liver cirrhosis based on literature review and the current clinical practice guidelines of the American Association for the Study of Liver Diseases (AASLD).

Clearance of pegylated interferon by Kupffer cells limits NK cell activation and therapy response of patients with HBV infection.

Pegylated interferon-α (PEG-IFN-α), where IFN-α is attached to polyethylene glycol (PEG), is an approved treatment for chronic hepatitis B virus (HBV) infection, a disease that causes liver-related morbidity and mortality in 257 million people worldwide. It is unknown why only a minority of patients respond to PEG-IFN-α. Using sequential blood samples and liver biopsies of patients with chronic HBV infection before, during, and after PEG-IFN-α treatment, we find that patients with early natural killer (NK) cell activation after PEG-IFN-α injection experienced greater liver inflammation, lysis of HBV-infected hepatocytes, and hepatitis B surface antigen (HBsAg) decline than those without. NK cell activation was associated with induction of interferon-stimulated genes and determined by PEG-IFN-α pharmacokinetics. Patients with delayed increases in PEG-IFN-α concentrations had greater amounts of PEG-specific immunoglobulin M (IgM) immune complexes in the blood and more PEG and IgM detected in the liver than patients with rapid increase in PEG-IFN-α concentration. This was associated with reduced NK cell activation. These results indicate that the immunomodulatory functions of PEG-IFN-α, particularly activation of NK cells, play a pivotal role in the response to treatment and further demonstrate that these functions are affected by PEG-IFN-α pharmacokinetics. Accelerated clearance of antibody-complexed pegylated drugs by Kupffer cells may be important beyond the field of HBV therapeutics. Thus, these findings may contribute to improving the efficacy of pegylated drugs that are now being developed for other chronic diseases and cancer.

Patient-reported outcomes on familial amyloid polyneuropathy (FAP).

BACKGROUND: Transthyretin familial amyloid polyneuropathy (ATTR-FAP) is a rare autosomal dominant inherited disease affecting multiple organ systems. ATTR-FAP patients' experiences have rarely been documented. The aim of this study was to collect patient reported outcomes across different countries to assess unmet needs and challenges. An anonymous survey was conducted at the 2nd European meeting on ATTR amyloidosis in Berlin in September 2019. Survey questions captured information on demographics, clinical characteristics, diagnostic experience, quality of life, disability and ATTR-FAP management. RESULTS: A total of 38 ATTR-FAP patients from 15 different countries participated in the survey. ATTR-FAP had a substantial impact on patients' day-to-day life, including difficulties in standing, walking, and participation in community activities. It also had negative effects on the mental health of patients. The survey highlighted several unmet needs and challenges from a patients' perspective, including (i) a need for increased awareness and a standardized diagnostic pathway, (ii) a need for better treatment access and supportive care and (iii) a need for better information about research and clinical trials. CONCLUSIONS: This global patient survey provides valuable findings to address ATTR-FAP patients' needs and challenges in order to further the goal of patient-centered care.

Tissue-resident T cells in hepatitis B: A new target for cure?

A hallmark of chronic hepatitis B virus (HBV) infection is the functional impairment and depletion of antiviral T cells. In this issue of JEM, Pallett et al. (https://doi.org/10.1084/jem.20162115) identify a reservoir of functional HBV-specific T cells among liver-resident T cells.