CD8+T cells from patients with cirrhosis display a phenotype that may contribute to cirrhosis-associated immune dysfunction

Amino Acid Metabolism and Immune Dysfunction in Urea Cycle Disorders: T and B Cell Perspectives

Urea cycle disorders (UCDs) are a group of genetic metabolic conditions characterized by enzyme deficiencies responsible for detoxifying ammonia. Hyperammonemia, the accumulation of intermediate metabolites, and a deficiency of essential amino acids-due to a protein-restrictive diet and the use of ammonia scavengers-can increase the risk of infections, particularly during metabolic crises. While the underlying mechanisms of immune suppression are still being fully elucidated, hyperammonemia may impair the function of immune cells, particularly T cells and macrophages, inhibiting the proliferation of T cells and cytokine production. Arginine, which is essential for T-cell activation and function, may also be limited in these patients, and its depletion can increase their vulnerability to infections. Twenty-four UCD patients and 31 healthy donors were recruited for the study. Peripheral lymphocyte subset analysis, intracellular protein and cytokine staining, and proliferation assays were performed by flow cytometry. Amino acid levels were measured using the HPLC method. The UCD patients exhibited low lymphocyte-proliferation capacity in both proximal and distal defects in response to phytohaemagglutinin (PHA) and anti-CD2, anti-CD3, and anti-CD28 (CD-mix), which was lower than healthy controls. Proximal-UCD patients exhibited a significantly higher response for IFN-γ compared to both distal-UCD patients and healthy controls. The different amino acids in the culture medium were changed significantly in the groups. This study highlights significant immune dysfunctions in UCD patients, particularly impaired T-cell proliferation and altered amino acid metabolism. Proximal UCD patients exhibited a higher IFN-γ response, indicating a potential for hyperinflammation. Despite this, infection rates did not significantly differ between proximal UCD and distal UCD patients, although distal UCD patients had higher hospitalization rates. Amino acid analysis revealed distinct metabolic disruptions, emphasizing the complex interplay between metabolism and immune function. These findings suggest that UCDs cause profound immune alterations, necessitating further research to develop targeted therapeutic strategies.

Mechanisms of immunity in acutely decompensated cirrhosis and acute-on-chronic liver failure

The identification of systemic inflammation (SI) as a central player in the orchestration of acute-on-chronic liver failure (ACLF) has opened new avenues for the understanding of the pathophysiological mechanisms underlying this disease condition. ACLF, which develops in patients with acute decompensation of cirrhosis, is characterized by single or multiple organ failure and high risk of short-term (28-day) mortality. Its poor outcome is closely associated with the severity of the systemic inflammatory response. In this review, we describe the key features of SI in patients with acutely decompensated cirrhosis and ACLF, including the presence of a high blood white cell count and increased levels of inflammatory mediators in systemic circulation. We also discuss the main triggers (i.e. pathogen- and damage-associated molecular patterns), the cell effectors (i.e. neutrophils, monocytes and lymphocytes), the humoral mediators (acute phase proteins, cytokines, chemokines, growth factors and bioactive lipid mediators) and the factors that influence the systemic inflammatory response that drive organ failure and mortality in ACLF. The role of immunological exhaustion and/or immunoparalysis in the context of exacerbated inflammatory responses that predispose ACLF patients to secondary infections and re-escalation of end-organ dysfunction and mortality are also reviewed. Finally, several new potential immunogenic therapeutic targets are debated.

Immune Dysfunction and Infection Risk in Advanced Liver Disease

The risk of microbial infections is increased in cirrhosis and other forms of advanced liver disease such as alcohol-associated hepatitis. Such infections may precipitate new or further decompensation and death, especially in patients with clinical features of acute-on-chronic liver failure. The severe immune dysfunction or "immune paralysis" caused by advanced liver disease is associated with high short-term mortality. However, the pathogenic mechanisms underlying immune dysfunction and immunodeficiency are incompletely understood. Evidence to date suggests a complex, dynamic process that perturbs the physiological roles of the liver as a master regulator of systemic immunity and protector against noxious effects of exogenous molecules in the portal vein flowing from the gut. Thus, in cirrhosis and severe alcohol-associated hepatitis, the ability of hepatocytes and intrahepatic immune cells to balance normal context-dependent dichotomous responses of tolerance vs immune activation is lost. Contributing factors include loss of the gut barrier with translocation of microbial products through the portal vein, culminating in development of functional defects in innate and adaptive immune cells, and generation of immune-regulatory myeloid cells that permit microbial colonization and infection. This review addresses key evidence supporting the paradigm of immune dysfunction as a risk for microbial infections and identifies potential therapeutic targets for intervention. The primary focus is on cirrhosis-associated immune dysfunction and alcohol-associated liver disease, because the bulk of available data are from these 2 conditions.

Distinct immunometabolic signatures in circulating immune cells define disease outcome in acute-on-chronic liver failure

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is a complication of cirrhosis characterized by multiple organ failure and high short-term mortality. The pathophysiology of ACLF involves elevated systemic inflammation leading to organ failure, along with immune dysfunction that heightens susceptibility to bacterial infections. However, it is unclear how these aspects are associated with recovery and nonrecovery in ACLF.

APPROACH AND RESULTS

Here, we mapped the single-cell transcriptome of circulating immune cells from patients with ACLF and acute decompensated (AD) cirrhosis and healthy individuals. We further interrogate how these findings, as well as immunometabolic and functional profiles, associate with ACLF-recovery (ACLF-R) or nonrecovery (ACLF-NR). Our analysis unveiled 2 distinct states of classical monocytes (cMons). Hereto, ACLF-R cMons were characterized by transcripts associated with immune and stress tolerance, including anti-inflammatory genes such as RETN and LGALS1 . Additional metabolomic and functional validation experiments implicated an elevated oxidative phosphorylation metabolic program as well as an impaired ACLF-R cMon functionality. Interestingly, we observed a common stress-induced tolerant state, oxidative phosphorylation program, and blunted activation among lymphoid populations in patients with ACLF-R. Conversely, ACLF-NR cMon featured elevated expression of inflammatory and stress response genes such as VIM , LGALS2 , and TREM1 , along with blunted metabolic activity and increased functionality.

CONCLUSIONS

This study identifies distinct immunometabolic cellular states that contribute to disease outcomes in patients with ACLF. Our findings provide valuable insights into the pathogenesis of ACLF, shedding light on factors driving either recovery or nonrecovery phenotypes, which may be harnessed as potential therapeutic targets in the future.

Changes of Peripheral T Cells in Systemic Lupus Erythematosus Patients

BACKGROUND

Efficient indicators for evaluating the imbalance of lymphocyte function were crucial to clinical therapy in systemic lupus erythematosus (SLE) patients. This study aimed to find biomarkers to assess lymphocyte-mediated immune response in SLE patients.

METHODS

A total of 81 SLE patients (non-active: n = 35, active: n = 46) and 70 healthy donors were recruited in the study. Peripheral blood was obtained, and flow cytometry was used to detect circulating lymphocytes.

RESULTS

Data showed that the counts of CD3+T, CD4+T, CD8+ T, and NK cells were decreased in active SLE patients compared with non-active SLE patients and healthy donors. The counts of peripheral T cells were increased in responders but decreased in non-responders among active patients. In addition, an increase in B cell counts was found in active SLE patients compared with those in the other two groups. Active SLE patients showed higher percentages of memory T cells but lower naive T cells than those in non-active SLE patients and healthy controls. Activation molecules (CD38 and HLA-DR) and inhibitory molecule PD-1 expressions on T cells were significantly higher but percentages of CD28+CD8+T cells were lower in active SLE patients compared with those in the other two groups.

CONCLUSION

This study indicated that monitoring the alterations of circulating lymphocyte counts and surface molecules may be helpful to assess disease activity of SLE patients, even discriminate active and non-active patients, which was beneficial to choose the best treatment option in clinical therapy.

The liver's dilemma: sensing real danger in a sea of PAMPs: the (arterial) sinusoidal segment theory

The liver is susceptible to viruses and bacterial infections, tumors, and sterile tissue damage, but immunological danger recognition in the liver is highly unconventional. When analyzing innate and adaptive immunity in the organ, the valid concepts that guide danger recognition and immune response in the periphery should be put aside. In the liver, the vascular anatomy is a game changer, as about 80% of the blood that percolates the organ arrives from the hepatic portal vein, draining blood rich in molecules from the intestinal flora. This 24/7 exposure to high amounts of pathogen-associated molecular pattern (PAMPs) molecules results in hepatic immunological tolerance. In the liver, dendritic, Kupffer (KC), liver sinusoidal endothelial cells (LSECs), and even hepatocytes express PD-L1, a T lymphocyte downregulatory molecule. Most cells express Fas-L, IL-10, TGF-β, low levels of co-stimulatory molecules, lack of or have low levels of MHC-I and/or MHC-II expression. Moreover, other negative regulators such as CTLA-4, IDO-1, and prostaglandin E2 (PGE2) are regularly expressed. Then, how can real danger be discerned and recognized in this sea of PAMPs? This is an open question. Here, we hypothesize that conventional immunological danger recognition can occur in the liver but in specific and minor arterial sinusoidal segments,. Then, in the portal triad, where the hepatic artery ramificates into the stroma and carries arterial blood with no gut-derived PAMPs, there is no evolutive or environmental pressure for immunosuppressive pathways, and conventional immunological danger recognition could occur. Therefore, in arterial sinusoidal segments with no sea of PAMPs, the liver could recognize real danger and support innate and adaptive immunity.

Liver sinusoidal endothelial cells regulate the balance between hepatic immunosuppression and immunosurveillance

As a metabolic center, the liver prevents inappropriate immune responses to abundant dietary antigens within the liver that could result in liver injury. This self-preservation mechanism can however decrease the efficiency of immunosurveillance of malignant cells by CD8 T cells. Hepatocellular carcinoma (HCC) is initiated by chronic viral infections, chronic alcohol consumption, and/or a fatty diet that leads to liver injury, fibrosis, and cirrhosis. HCC patients have high levels of dysfunctional and exhausted T cells, however, it is unclear which stage of HCC development contributes to T cell dysfunction. Repair of liver injury is initiated by interactions between injured hepatocytes and liver sinusoidal endothelial cells (LSEC), however, chronic injury can lead to fibrosis. Here, using a diethylnitrosamine/carbon tetrachloride (DEN/CCl4) mouse model of early HCC development, we demonstrate that chronic liver injury and fibrosis are sufficient to induce a CD8 T cell exhaustion signature with a corresponding increase in expression of immunosuppressive molecules on LSEC. We show that LSEC alter T cell function at various stages of T cell differentiation/activation. LSEC compete with dendritic cells presenting the same antigen to naïve CD8 T cells resulting in a unique T cell phenotype. Furthermore, LSEC abrogate killing of target cells, in an antigen-dependent manner, by previously activated effector CD8 T cells, and LSEC change the effector cell cytokine profile. Moreover, LSEC induce functional T cell exhaustion under low dose chronic stimulation conditions. Thus, LSEC critically regulate the balance between preventing/limiting liver injury and permitting sufficient tumor immunosurveillance with normal hepatic functions likely contributing to HCC development under conditions of chronic liver insult.

Liver damage and immune responses

Chronic liver disease (CLD) has massive systemic repercussions including major impacts on the body's immune system. Abnormalities in phenotype, function and numbers of various immune cell subsets have been established by a large number of clinical and pre-clinical studies. The loss of essential immune functions renders CLD-patients exceptionally susceptible to bacterial and viral infections and also impairs the efficacy of vaccination. Consequently, infections represent a major clinical issue causing significant morbidity and mortality in these patients. Mechanistically, the immune dysfunction associated with CLD results from the increased translocation of bacteria and bacterial cues from the intestine. These trigger a signaling axis around the cytokines IFN I and IL-10 in hepatic myeloid cells, which aside from impairing the function of the myeloid cells themselves, also has notable negative impacts on the functionality of other immune cells. T cells in CLD-patients and -models are especially affected by this signaling axis and display a variety of quantitative and qualitative defects. Due to the high clinical relevance, understanding the mechanisms underlaying CED-associated immune dysfunction is of critical importance to discover and develop new therapeutic targets.

Single cell-spatial transcriptomics and bulk multi-omics analysis of heterogeneity and ecosystems in hepatocellular carcinoma

This study profiled global single cell-spatial-bulk transcriptome landscapes of hepatocellular carcinoma (HCC) ecosystem from six HCC cases and a non-carcinoma liver control donor. We discovered that intratumoral heterogeneity mainly derived from HCC cells diversity and pervaded the genome-transcriptome-proteome-metabolome network. HCC cells are the core driving force of taming tumor-associated macrophages (TAMs) with pro-tumorigenic phenotypes for favor its dominant growth. Remarkably, M1-types TAMs had been characterized by disturbance of metabolism, poor antigen-presentation and immune-killing abilities. Besides, we found simultaneous cirrhotic and HCC lesions in an individual patient shared common origin and displayed parallel clone evolution via driving disparate immune reprograms for better environmental adaptation. Moreover, endothelial cells exhibited phenotypically conserved but executed differential functions in a space-dependent manner. Further, the spatiotemporal traits of rapid recurrence niche genes were identified and validated by immunohistochemistry. Our data unravels the great significance of HCC cells in shaping vibrant tumor ecosystems corresponding to clinical scenarios.

COVID-19-related liver injury: Mechanisms, diagnosis, management; its impact on pre-existing conditions, cancer and liver transplant: A comprehensive review

AIMS

This review explores the mechanisms, diagnostic approaches, and management strategies for COVID-19-induced liver injury, with a focus on its impact on patients with pre-existing liver conditions, liver cancer, and those undergoing liver transplantation.

MATERIALS AND METHODS

A comprehensive literature review included studies on clinical manifestations of liver injury due to COVID-19. Key areas examined were direct viral effects, drug-induced liver injury, cytokine storms, and impacts on individuals with chronic liver diseases, liver transplants, and the role of vaccination. Data were collected from clinical trials, observational studies, case reports, and review literature.

KEY FINDINGS

COVID-19 can cause a spectrum of liver injuries, from mild enzyme elevations to severe hepatic dysfunction. Injury mechanisms include direct viral invasion, immune response alterations, drug toxicity, and hypoxia-reperfusion injury. Patients with chronic liver conditions (such as alcohol-related liver disease, nonalcoholic fatty liver disease, cirrhosis, and hepatocellular carcinoma) face increased risks of severe outcomes. The pandemic has worsened pre-existing liver conditions, disrupted cancer treatments, and complicated liver transplantation. Vaccination remains crucial for reducing severe disease, particularly in chronic liver patients and transplant recipients. Telemedicine has been beneficial in managing patients and reducing cross-infection risks.

SIGNIFICANCE

This review discusses the importance of improved diagnostic methods and management strategies for liver injury caused by COVID-19. It emphasizes the need for close monitoring and customized treatment for high-risk groups, advocating for future research to explore long-term effects, novel therapies, and evidence-based approaches to improve liver health during and after the pandemic.

Liver cirrhosis is a risk-factor for Pneumocystis jirovecii associated mortality

Background

Pneumocystis jirovecci pneumonia (PCP) is a life threating disease in immunodeficient patients. Liver cirrhosis itself can lead to immunodefiency, however little is known if Pneumocystis jirovecci infection affects the outcome of patients with liver cirrhosis.

Aim

We aimed to assess the predictors for Pneumocystis jirovecci-associated mortality in patients with Pneumocystis jirovecci infection treated at intensive care units.

Methods

A total of 151 patients hospitalized between January 2013 and November 2019 with a PCR-confirmed Pneumocystis jirovecci infection were retrospectively included in this study and analysed for clinical predictors for PCJ associated mortality.

Results

The overall mortality in our patient cohort was 60%. Out of 151 patients included in the analysis, 67 (44%) patients suffered from liver cirrhosis. Patients with an advanced liver cirrhosis (Child-Pugh class C) showed the highest mortality rate of 84.7%. The presence of a liver cirrhosis was associated with a significant increased risk of mortality (OR: 4.809) ([95%-CI: 2.32-9.97]; p < 0.001). There was a significant correlation of Meld score and mortality (r = 0.612, p < 0.001).

Discussion

To our knowledge, this study represents the largest evaluation of Pneumocystis jirovecci infection in patients with advanced liver cirrhosis. Cirrhosis associated immune dysfunction (CAID) describes the spectrum of immunological disturbances in patients with cirrhosis, which is linked to a heightened vulnerability to bacterial infections. Our data indicate a heightened susceptibility to fungal infections. Understanding the phenotypic manifestations of CAID could lead to immune-targeted therapies aimed at reducing infection susceptibility and decreasing CAID-associated mortality in cirrhosis patients.

Infections in decompensated cirrhosis: Pathophysiology, management, and research agenda

Bacterial infections in patients with cirrhosis lead to a 4-fold increase in mortality. Immune dysfunction in cirrhosis further increases the risk of bacterial infections, in addition to alterations in the gut microbiome, which increase the risk of pathogenic bacteria. High rates of empiric antibiotic use contribute to increased incidence of multidrug-resistant organisms and further increases in mortality. Despite continous advances in the field, major unknowns regarding interactions between the immune system and the gut microbiome and strategies to reduce infection risk and improve mortality deserve further investigation. Here, we highlight the unknowns in these major research areas and make a proposal for a research agenda to move toward improving disease progression and outcomes in patients with cirrhosis and infections.

Liver cirrhosis: current status and treatment options using western or traditional Chinese medicine

Liver cirrhosis arises from liver fibrosis and necroinflammation caused by various mechanisms of hepatic injury. It is a prevalent condition in clinical practice characterized by hepatocellular dysfunction, portal hypertension, and associated complications. Despite its common occurrence, the etiology and pathogenesis of liver cirrhosis remain incompletely understood, posing a significant health threat. Effective prevention of its onset and progression is paramount in medical research. Symptoms often include discomfort in the liver area, while complications such as sarcopenia, hepatic encephalopathy, ascites, upper gastrointestinal bleeding, and infection can arise. While the efficacy of Western medicine in treating liver cirrhosis is uncertain, Chinese medicine offers distinct advantages. This review explores advancements in liver cirrhosis treatment encompassing non-pharmacological and pharmacological modalities. Chinese medicine interventions, including Chinese medicine decoctions, Chinese patent medicines, and acupuncture, exhibit notable efficacy in cirrhosis reversal and offer improved prognoses. Nowadays, the combination of Chinese and Western medicine in the treatment of liver cirrhosis also has considerable advantages, which is worthy of further research and clinical promotion. Standardized treatment protocols based on these findings hold significant clinical implications.

Harnessing CD8+ T cell dynamics in hepatitis B virus-associated liver diseases: Insights, therapies and future directions

Hepatitis B virus (HBV) infection playsa significant role in the etiology and progression of liver-relatedpathologies, encompassing chronic hepatitis, fibrosis, cirrhosis, and eventual hepatocellularcarcinoma (HCC). Notably, HBV infection stands as the primary etiologicalfactor driving the development of HCC. Given the significant contribution ofHBV infection to liver diseases, a comprehensive understanding of immunedynamics in the liver microenvironment, spanning chronic HBV infection,fibrosis, cirrhosis, and HCC, is essential. In this review, we focused on thefunctional alterations of CD8+ T cells within the pathogenic livermicroenvironment from HBV infection to HCC. We thoroughly reviewed the roles ofhypoxia, acidic pH, metabolic reprogramming, amino acid deficiency, inhibitory checkpointmolecules, immunosuppressive cytokines, and the gut-liver communication in shapingthe dysfunction of CD8+ T cells in the liver microenvironment. Thesefactors significantly impact the clinical prognosis. Furthermore, we comprehensivelyreviewed CD8+ T cell-based therapy strategies for liver diseases,encompassing HBV infection, fibrosis, cirrhosis, and HCC. Strategies includeimmune checkpoint blockades, metabolic T-cell targeting therapy, therapeuticT-cell vaccination, and adoptive transfer of genetically engineered CD8+ T cells, along with the combined usage of programmed cell death protein-1/programmeddeath ligand-1 (PD-1/PD-L1) inhibitors with mitochondria-targeted antioxidants.Given that targeting CD8+ T cells at various stages of hepatitis Bvirus-induced hepatocellular carcinoma (HBV + HCC) shows promise, we reviewedthe ongoing need for research to elucidate the complex interplay between CD8+ T cells and the liver microenvironment in the progression of HBV infection toHCC. We also discussed personalized treatment regimens, combining therapeuticstrategies and harnessing gut microbiota modulation, which holds potential forenhanced clinical benefits. In conclusion, this review delves into the immunedynamics of CD8+ T cells, microenvironment changes, and therapeuticstrategies within the liver during chronic HBV infection, HCC progression, andrelated liver diseases.

Fungal infections in liver cirrhosis

Liver cirrhosis is a chronic condition that is associated with a variety of complications across organ systems. Patients with cirrhosis also suffer from immune dysfunction, which may predispose them to catastrophic bacterial and fungal infections. Bacterial infections in liver cirrhosis have been well-documented, however, data remains scarce regarding fungal infections. Candida and Aspergillus have been reported as the most common pathogens among patients with cirrhosis, causing both invasive and non-invasive infections. However, other pathogens such as Coccidioides, Pneumocystis, Cryptococcus, and Rhizopus have been increasing in incidence. Diagnosis of fungal infection is often difficult, particularly in regards to distinguishing colonization from invasive infection. Serum markers such as beta-D-glucan (BDG) and galactomannan are beneficial diagnostic tools in conjunction with fungal cultures and imaging modalities. Bronchoscopy with bronchoalveolar lavage (BAL) or lung biopsy can be useful adjuncts as well. Liver transplantation is another important consideration as invasive fungal infection (IFI) is a contraindication to transplant surgery. Additionally, patients are at increased risk for infection due to immunosuppression in the post-transplant period. We aim to discuss the mechanisms responsible for immune dysfunction in advanced liver disease, the epidemiology of fungal infections in this population, as well as presentations and management considerations pertaining to specific pathogens and antifungal regimens.

Heterogenous liver parenchymal enhancement in CT is a favorable prognosis of HCC after hepatic resection

This study aimed to define the role of heterogeneity of liver parenchymal enhancement on computed tomography (CT) in the survival of patients with hepatocellular carcinoma (HCC) after hepatic resection. The medical records of patients with HCCs and who had undergone hepatic resection were retrospectively reviewed. The standard deviation (SD) of three different enhanced CT scan images was used to estimate the heterogeneity of liver parenchymal enhancement: SD of > 5.6, heterogenous enhancement, and SD of ≤ 5.6, homogeneous enhancement. A total of 57 patients had heterogenous enhancement, and 143 patients had homogeneous enhancement. The patients with heterogenous enhancement had longer disease-free and overall survivals than those with other enhancements (log-rank test, P < 0.001 and P = 0.036). The pathologic exam showed that heterogenous enhancement tended to develop septa in the peritumoral liver tissues. The prevalence of CD8+ cells was significantly higher in the peritumor liver tissues with septa than in those without (0.83% vs. 0.26%, P < 0.001). The peritumoral CD8/Foxp3 ratio was higher in the liver tissues with septa than in those without (1.22 vs. 0.47, P = 0.001), and patients with CD8/Foxp3 of > 0.8 had better overall survival than those with CD8/Foxp3 of ≤ 0.8 (log-rank test, P = 0.028). In conclusion, patients who had undergone hepatic resection with a heterogenous liver parenchymal enhancement tended to develop hepatic septa, which was associated with a higher CD8/Foxp3 ratio and longer survival. Therefore, contrast-enhanced CT scans might be a useful tool to predict the outcome of HCC.

CXCR6+CD69+ CD8+ T cells in ascites are associated with disease severity in patients with cirrhosis

Background & Aims

Patients with advanced cirrhosis often develop hepatic decompensation, which is accompanied by systemic inflammation and may eventually lead to acute-on-chronic liver failure. One important cause of systemic hyperinflammation is a dysregulated overshooting immune response in ascites in the abdominal cavity. In this study, we analyzed the role of CD8+ T cells in the ascites immune compartment.

Methods

Peripheral blood and ascites fluid were collected from 50 patients with decompensated cirrhosis. Phenotype and functional responses of CD8+ T cells were analyzed, and obtained data were compared with each other as well as with healthy controls and patients with compensated cirrhosis.

Results

High-dimensional flow cytometry revealed that CD8+ T cells are abundant in the ascites of patients with cirrhosis and exhibit a chronically activated bystander phenotype with innate-like functions. Indeed, we identified distinct CXCR6+CD69+ clusters of late effector memory CD8+ T cells that were rarely found in blood and correlated with clinical parameters of disease severity. Moreover, this CD8+ T-cell population was hyperresponsive to innate cytokines and exhibited cytokine-mediated bystander activation. Interestingly, the Janus kinase (JAK) inhibitor tofacitinib was able to effectively block bystander-activated CXCR6+CD69+ CD8+ T cells and significantly suppress effector molecule production.

Conclusions

The results indicate that CXCR6+CD69+ CD8+ T cells in ascites are associated with disease severity and may contribute to inflammation in patients with decompensated cirrhosis, suggesting that targeted inhibition of this immune cell subset may be a viable therapeutic option.

Impact and Implications

Patients with advanced cirrhosis often develop hepatic decompensation, which is accompanied by systemic inflammation and eventually leads to acute-on-chronic liver failure. One important cause of systemic hyperinflammation is a dysregulated overshooting immune response in ascites in the abdominal cavity. In this study, we demonstrate that CXCR6+CD69+ CD8+ T cells are abundant in the ascites of patients with cirrhosis, exhibit a chronically activated bystander phenotype, and correlate with clinical parameters of disease severity. Moreover, we show that the Janus kinase (JAK) inhibitor tofacitinib can effectively block these bystander-activated CXCR6+CD69+ CD8+ T cells, suggesting that targeted inhibition of this immune cell subset may be a potential therapeutic strategy.

Clinical trial number

Prospective registry: INFEKTA (DRKS00010664).

Immunopathogenesis of acute on chronic liver failure

Acute-on-chronic liver failure is a well-established description of a high-mortality syndrome of chronic liver disease (usually cirrhosis) with organ failure. While the exact definition is under refinement, the accepted understanding of this entity is in patients with chronic liver disease and various organs in failure and where systemic inflammation is a major component of the pathobiology. There are limited therapies for a disease with such a poor prognosis, and while improvements in the critical care management and for very few patients, liver transplantation, mean 50% can survive to hospital discharge, rapid application of new therapies is required. Here we explain the current understanding of the immunologic abnormalities seen in acute-on-chronic liver failure across the innate and adaptive immune systems, the role of the hepatic cell death and the gut-liver axis, and recommendations for future research and treatment paradigms.

Vaccine Responses in Patients with Liver Cirrhosis: From the Immune System to the Gut Microbiota

Vaccines prevent a significant number of deaths annually. However, certain populations do not respond adequately to vaccination due to impaired immune systems. Cirrhosis, a condition marked by a profound disruption of immunity, impairs the normal immunization process. Critical vaccines for cirrhotic patients, such as the hepatitis A virus (HAV), hepatitis B virus (HBV), influenza, pneumococcal, and coronavirus disease 19 (COVID-19), often elicit suboptimal responses in these individuals. The humoral response, essential for immunization, is less effective in cirrhosis due to a decline in B memory cells and an increase in plasma blasts, which interfere with the creation of a long-lasting response to antigen vaccination. Additionally, some T cell subtypes exhibit reduced activation in cirrhosis. Nonetheless, the persistence of memory T cell activity, while not preventing infections, may help to attenuate the severity of diseases in these patients. Alongside that, the impairment of innate immunity, particularly in dendritic cells (DCs), prevents the normal priming of adaptive immunity, interrupting the immunization process at its onset. Furthermore, cirrhosis disrupts the gut-liver axis balance, causing dysbiosis, reduced production of short-chain fatty acids (SCFAs), increased intestinal permeability, and bacterial translocation. Undermining the physiological activity of the immune system, these alterations could impact the vaccine response. Enhancing the understanding of the molecular and cellular factors contributing to impaired vaccination responses in cirrhotic patients is crucial for improving vaccine efficacy in this population and developing better prevention strategies.

Endotoxin Inflammatory Action on Cells by Dysregulated-Immunological-Barrier-Linked ROS-Apoptosis Mechanisms in Gut-Liver Axis

Our study highlighted the immune changes by pro-inflammatory biomarkers in the gut-liver-axis-linked ROS-cell death mechanisms in chronic and acute inflammations when gut cells are exposed to endotoxins in patients with hepatic cirrhosis or steatosis. In duodenal tissue samples, gut immune barrier dysfunction was analyzed by pro-inflammatory biomarker expressions, oxidative stress, and cell death by flow cytometry methods. A significant innate and adaptative immune system reaction was observed as result of persistent endotoxin action in gut cells in chronic inflammation tissue samples recovered from hepatic cirrhosis with the A-B child stage. Instead, in patients with C child stage of HC, the endotoxin tolerance was installed in cells, characterized by T lymphocyte silent activation and increased Th1 cytokines expression. Interesting mechanisms of ROS-cell death were observed in chronic and acute inflammation samples when gut cells were exposed to endotoxins and immune changes in the gut-liver axis. Late apoptosis represents the chronic response to injury induction by the gut immune barrier dysfunction, oxidative stress, and liver-dysregulated barrier. Meanwhile, necrosis represents an acute and severe reply to endotoxin action on gut cells when the immune system reacts to pro-inflammatory Th1 and Th2 cytokines releasing, offering protection against PAMPs/DAMPs by monocytes and T lymphocyte activation. Flow cytometric analysis of pro-inflammatory biomarkers linked to oxidative stress-cell death mechanisms shown in our study recommends laboratory techniques in diagnostic fields.

Consensus document on acute-on-chronic liver failure (ACLF) established by the Mexican Association of Hepatology

Acute-on chronic liver failure (ACLF) has been an intensively debated topic mainly due to the lack of a unified definition and diagnostic criteria. The growing number of publications describing the mechanisms of ACLF development, the progression of the disease, outcomes and treatment has contributed to a better understanding of the disease, however, it has also sparked the debate about this condition. As an attempt to provide medical professionals with a more uniform definition that could be applied to our population, the first Mexican consensus was performed by a panel of experts in the area of hepatology in Mexico. We used the most relevant and impactful publications along with the clinical and research experience of the consensus participants. The consensus was led by 4 coordinators who provided the most relevant bibliography by doing an exhaustive search on the topic. The entire bibliography was made available to the members of the consensus for consultation at any time during the process and six working groups were formed to develop the following sections: 1.- Generalities, definitions, and criteria, 2.- Pathophysiology of cirrhosis, 3.- Genetics in ACLF, 4.- Clinical manifestations, 5.- Liver transplantation in ACLF, 6.- Other treatments.

Presence of MDSC associates with impaired antigen-specific T cell reactivity following COVID-19 vaccination in cirrhotic patients

Background and aims

Cirrhosis entails high risk of serious infections and abated efficiency of vaccination, but the underlying mechanisms are only partially understood. This study aimed at characterizing innate and adaptive immune functions, including antigen-specific T cell responses to COVID-19 vaccination, in patients with compensated and decompensated cirrhosis.

Methods

Immune phenotype and function in peripheral blood from 42 cirrhotic patients and 44 age-matched healthy controls were analysed after two doses of the mRNA-based COVID-19 vaccines [BNT162b2 (Pfizer BioNTech) or mRNA-1273 (Moderna)].

Results

Cirrhotic patients showed significantly reduced blood counts of antigen-presenting dendritic cells (DC) and high counts of monocytic myeloid-derived suppressor cells (M-MDSC) as compared to healthy controls. In addition, monocytic cells recovered from cirrhotic patients showed impaired expression of the antigen-presenting molecule HLA-DR and the co-stimulatory molecule CD86 upon Toll-like receptor (TLR) stimulation. These features were more prominent in patients with decompensated cirrhosis (Child-Pugh classes B & C). Interestingly, while patients with compensated cirrhosis (Child-Pugh class A) showed an inflammatory profile with myeloid cells producing the proinflammatory cytokines IL-6 and TNF, decompensated patients produced reduced levels of these cytokines. Cirrhotic patients, in particular those with more advanced end-stage liver disease, mounted reduced antigen-specific T cell reactivity to COVID-19 vaccination. Vaccine efficiency inversely correlated with levels of M-MDSC.

Conclusion

These results implicate MDSC as mediators of immunosuppression, with ensuing deficiency of vaccine-specific T cell responses, in cirrhosis.

Tissue-resident and innate-like T cells in patients with advanced chronic liver disease

Chronic liver disease results from the orchestrated interplay of components of innate and adaptive immunity in response to liver tissue damage. Recruitment, positioning, and activation of immune cells can contribute to hepatic cell death, inflammation, and fibrogenesis. With disease progression and increasing portal pressure, repeated translocation of bacterial components from the intestinal lumen through the epithelial and vascular barriers leads to persistent mucosal, hepatic, and systemic inflammation which contributes to tissue damage, immune dysfunction, and microbial infection. It is increasingly recognised that innate-like and adaptive T-cell subsets located in the liver, mucosal surfaces, and body cavities play a critical role in the progression of advanced liver disease and inflammatory complications of cirrhosis. Mucosal-associated invariant T cells, natural killer T cells, γδ T cells, and tissue-resident memory T cells in the gut, liver, and ascitic fluid share certain characteristic features, which include that they recognise microbial products, tissue alarmins, cytokines, and stress ligands in tissues, and perform effector functions in chronic liver disease. This review highlights recent advances in the comprehension of human tissue-resident and unconventional T-cell populations and discusses the mechanisms by which they contribute to inflammation, fibrosis, immunosuppression, and antimicrobial surveillance in patients with cirrhosis. Understanding the complex interactions of immune cells in different compartments and their contribution to disease progression will provide further insights for effective diagnostic interventions and novel immunomodulatory strategies in patients with advanced chronic liver disease.

Catch-up antibody responses and hybrid immunity in mRNA vaccinated patients at risk of severe COVID-19

BACKGROUND

The immunogenicity of repeated vaccination and hybrid immunity in vulnerable patients remains unclear.

METHODS

We studied the impact of iterative Covid-19 mRNA vaccination and hybrid immunity on antibody levels in immunosuppressed subjects. Patients with liver cirrhosis (n = 38), survivors of allogeneic haematopoietic stem cell transplantation (allo-HSCT) (n = 36) and patients with autoimmune liver disease (n = 14) along with healthy controls (n = 20) were monitored for SARS-CoV-2-S1 IgG after their 1st-3rd vaccine doses, 31 of whom became infected with the Omicron variant after the 2nd dose. Ten uninfected allo-HSCT recipients received an additional 4th vaccine dose.

RESULTS

Unexpectedly, immunosuppressed patients achieved antibody levels in parity with controls after the 3rd vaccine dose. In all study cohorts, hybrid immunity (effect of vaccination and natural infection) resulted in approximately 10-fold higher antibody levels than vaccine-induced immunity alone.

CONCLUSIONS

Three doses of the Covid-19 mRNA vaccine entailed high antibody concentrations even in immunocompromised individuals, and hybrid-immunity resulted further augmented levels than vaccination alone. Clinical trial registration: EudraCT 2021-000349-42.

Hepatic T-cell senescence and exhaustion are implicated in the progression of fatty liver disease in patients with type 2 diabetes and mouse model with nonalcoholic steatohepatitis

Immunosenescence and exhaustion are involved in the development and progression of type 2 diabetes (T2D) and metabolic liver diseases, including fatty liver, fibrosis, and cirrhosis, in humans. However, the relationships of the senescence and exhaustion of T cells with insulin resistance-associated liver diseases remain incompletely understood. To better define the relationship of T2D with nonalcoholic fatty liver disease, 59 patients (mean age 58.7 ± 11.0 years; 47.5% male) with T2D were studied. To characterize their systemic immunophenotypes, peripheral blood mononuclear cells were analyzed using flow cytometry. Magnetic resonance imaging (MRI)-based proton density fat fraction and MRI-based elastography were performed using an open-bore, vertical-field 3.0 T scanner to quantify liver fat and fibrosis, respectively. The participants with insulin resistance had a significantly larger population of CD28 - CD57+ senescent T cells among the CD4+ and CD8 + T cells than those with lower Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) values. The abundances of senescent CD4+ and CD8 + T cells and the HOMA-IR positively correlated with the severity of liver fibrosis, assessed using MRI-based elastography. Interleukin 15 from hepatic monocytes was found to be an inducer of bystander activation of T cells, which is associated with progression of liver disease in the participants with T2D. Furthermore, high expression of genes related to senescence and exhaustion was identified in CD4+ and CD8 + T cells from the participants with nonalcoholic steatohepatitis or liver cirrhosis. Finally, we have also demonstrated that hepatic T-cell senescence and exhaustion are induced in a diet or chemical-induced mouse model with nonalcoholic steatohepatitis. In conclusion, we have shown that T-cell senescence is associated with insulin resistance and metabolic liver disease in patients with T2D.

COVID-19 associated liver injury: An updated review on the mechanisms and management of risk groups

Coronavirus disease 2019 (COVID-19) has been associated with various liver injury cases worldwide. To date, the prevalence, mechanism, clinical manifestations, diagnosis, and outcomes of COVID-19-induced liver injury in various at-risk groups are not well defined. Liver injury may arise in the prevention and treatment of COVID-19 from direct causes such as viral infection and indirect causes such as systemic inflammation, hypoxic changes, and drugs that exacerbate any pre-existing liver disease. Studies have found that patients with underlying liver disease are at higher risk of COVID-19-induced liver injury. Certain condition of cardiopulmonary and metabolic diseases and vulnerable stages in lifespan may also involve in the development of COVID-19-induced liver injury. This review summarized studies of COVID-19-induced liver injury in different at-risk groups regarding their clinical characteristics, parameters, and correlations of the severity with these indicators and signs as well as potential treatment suggestions, to increase attention to physiological and pathological conditions and continue liver function monitoring as they can help in strengthening early supportive treatment and reducing the incidence of adverse outcomes.

Dysfunctions of Circulating Adaptive Immune Cells in End-Stage Liver Disease

End-stage liver disease (ESLD) from acute liver failure to compensated advanced chronic liver disease and decompensated cirrhosis at different stages (chronic decompensation, acute decompensation with or without acute-on-chronic liver failure) has high disease severity and poor patient outcome. Infection is a common complication in patients with ESLD and it is associated with a high mortality rate. Multiple mechanisms are involved in this marked susceptibility to infections, noticeably the inadequate immune response known as immune paresis, as part of cirrhosis-associated immune dysfunction (CAID). Specifically in the adaptive immune arm, lymphocyte impairments—including inadequate activation, reduced ability to secrete effector molecules and enhanced immune suppressive phenotypes—result in compromised systemic immune responses and increased risk of infections. This review summarises current knowledge of alterations in adaptive immune responsiveness and their underlying mechanisms in ESLD. Understanding these mechanisms is of crucial importance in the identification of potential therapeutic targets and applications of targeted treatments beyond antimicrobials, such as immunotherapy.

Dynamics of the inhibitory immune checkpoint TIM-3 in mouse pulmonary phagocytes after silica exposure

Long-term inhalation of silica particles in the workplace causes silicosis, which is incurable and seriously endangers the health of workers. It is believed that silicosis is caused by an imbalance of the pulmonary immune microenvironment, in which pulmonary phagocytes play a crucial role. As an emerging immunomodulatory factor, it is unclear whether T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) participate in silicosis by modulating pulmonary phagocytes function. The purpose of this study was to investigate the dynamic changes of the TIM-3 in pulmonary macrophages, dendritic cells (DCs), and monocytes during the development of silicosis in mice. The plasma levels of soluble TIM-3 in silicosis patients were also examined. Flow cytometry was used to identify alveolar macrophages (AMs), interstitial macrophages (IMs), CD11b+ DC, CD103+ DC, Ly6C+, and Ly6C- monocytes in mouse lung tissues, and further analyses were conducted on the expression of TIM-3. Results showed that soluble TIM-3 was significantly elevated in plasma of silicosis patients, and the level of which was higher in stage II and III patients than that in stage I. In silicosis mice, the protein and mRNA levels of TIM-3 and Galectin9 were significantly upregulated in lung tissues. Specific to pulmonary phagocytes, silica exposure affected TIM-3 expression in a cell-specific and dynamic manner. In macrophages, TIM-3 expression upregulated in AM after 28 days and 56 days of silica instillation, while the expression of TIM-3 in IM decreased at all observation time points. In DCs, silica exposure only caused a decrease of TIM-3 expression in CD11b+ DCs. In monocytes, TIM-3 dynamics in Ly6C+ and Ly6C- monocytes were generally consistent during silicosis development, which significant decrease after 7 and 28 days of silica exposure. In conclusion, TIM-3 may mediate the development of silicosis by regulating pulmonary phagocytes.

Interferon-induced IL-10 drives systemic T-cell dysfunction during chronic liver injury

BACKGROUND & AIMS

Patients with chronic liver disease (CLD), including cirrhosis, are at increased risk of intractable viral infections and are hyporesponsive to vaccination. Hallmarks of CLD and cirrhosis include microbial translocation and elevated levels of type I interferon (IFN-I). We aimed to investigate the relevance of microbiota-induced IFN-I in the impaired adaptive immune responses observed in CLD.

METHODS

We combined bile duct ligation (BDL) and carbon tetrachloride (CCl4) models of liver injury with vaccination or lymphocytic choriomeningitis virus infection in transgenic mice lacking IFN-I in myeloid cells (LysM-Cre IFNARflox/flox), IFNAR-induced IL-10 (MX1-Cre IL10flox/flox) or IL-10R in T cells (CD4-DN IL-10R). Key pathways were blocked in vivo with specific antibodies (anti-IFNAR and anti-IL10R). We assessed T-cell responses and antibody titers after HBV and SARS-CoV-2 vaccinations in patients with CLD and healthy individuals in a proof-of-concept clinical study.

RESULTS

We demonstrate that BDL- and CCL4-induced prolonged liver injury leads to impaired T-cell responses to vaccination and viral infection in mice, subsequently leading to persistent infection. We observed a similarly defective T-cell response to vaccination in patients with cirrhosis. Innate sensing of translocated gut microbiota induced IFN-I signaling in hepatic myeloid cells that triggered excessive IL-10 production upon viral infection. IL-10R signaling in antigen-specific T cells rendered them dysfunctional. Antibiotic treatment and inhibition of IFNAR or IL-10Ra restored antiviral immunity without detectable immune pathology in mice. Notably, IL-10Ra blockade restored the functional phenotype of T cells from vaccinated patients with cirrhosis.

CONCLUSION

Innate sensing of translocated microbiota induces IFN-/IL-10 expression, which drives the loss of systemic T-cell immunity during prolonged liver injury.

IMPACT AND IMPLICATIONS

Chronic liver injury and cirrhosis are associated with enhanced susceptibility to viral infections and vaccine hyporesponsiveness. Using different preclinical animal models and patient samples, we identified that impaired T-cell immunity in BDL- and CCL4-induced prolonged liver injury is driven by sequential events involving microbial translocation, IFN signaling leading to myeloid cell-induced IL-10 expression, and IL-10 signaling in antigen-specific T cells. Given the absence of immune pathology after interference with IL-10R, our study highlights a potential novel target to reconstitute T-cell immunity in patients with CLD that can be explored in future clinical studies.

COVID-19 and severity of liver diseases: Possible crosstalk and clinical implications

COVID-19-infected individuals and those who recovered from the infection have been demonstrated to have elevated liver enzymes or abnormal liver biochemistries, particularly with preexisting liver diseases, liver metabolic disorders, viral hepatitis, and other hepatic comorbidities. However, possible crosstalk and intricate interplay between COVID-19 and liver disease severity are still elusive, and the available data are murky and confined. Similarly, the syndemic of other blood-borne infectious diseases, chemical-induced liver injuries, and chronic hepatic diseases continued to take lives while showing signs of worsening due to the COVID-19 crisis. Moreover, the pandemic is not over yet and is transitioning to becoming an epidemic in recent years; hence, monitoring liver function tests (LFTs) and assessing hepatic consequences of COVID-19 in patients with or without liver illnesses would be of paramount interest. This pragmatic review explores the correlations between COVID-19 and liver disease severity based on abnormal liver biochemistries and other possible mechanisms in individuals of all ages from the emergence of the COVID-19 pandemic to the post-pandemic period. The review also alludes to clinical perspectives of such interactions to curb overlapping hepatic diseases in people who recovered from the infection or living with long COVID-19.

Dysregulated biomarkers of innate and adaptive immunity predict infections and disease progression in cirrhosis

Background & Aims

Cirrhosis-associated immune dysfunction (CAID) affects both innate and adaptive immunity. This study investigated the complement system, immunoglobulins, and acute-phase proteins and their prognostic relevance in patients with advanced chronic liver disease (ACLD).

Methods

Patients with ACLD (hepatic venous pressure gradient [HVPG] ≥6 mmHg) but without acute decompensation/infections were characterised by HVPG and by clinical EASL stages: compensated (cACLD; S0-2) vs. decompensated ACLD (dACLD) with previous variceal bleeding (S3), non-bleeding decompensation (S4), or further decompensation (S5). Complement factors (C3c, C4, CH50), immunoglobulins (IgA, IgM, IgG, IgG1-4), acute-phase proteins and systemic inflammation biomarkers (white blood cells, C-reactive protein, IL-6, procalcitonin) were measured.

Results

A total of 245 patients (median model for end-stage liver disease score: 11 [9-15], median HVPG: 17 [12-21] mmHg) were included with 150 (61%) presenting dACLD. Complement levels and activity significantly decreased in dACLD substages S4 and S5 (p <0.001). Total IgA/IgM/IgG and IgG1-4 subtype levels increased in patients with dACLD (all p <0.05). Complement and immunoglobulin levels correlated negatively and positively, respectively, with systemic inflammation (all p <0.05). High IgG-1 (adjusted hazard ratio per 100 mg/dl: 1.12, 1.04-1.19, p = 0.002) and IL-6 (adjusted hazard ratio: 1.03, 1.00-1.05, p = 0.023) levels predicted the development of infections during follow-up. High IgA (stratified by median; log-rank p <0.001), high IgG1 (log-rank p = 0.043) and low C3c (log-rank p = 0.003) indicated a higher risk of first/further decompensation or liver-related death (composite endpoint). Next to HVPG and IL-6, low C3c (adjusted hazard ratio per mg/dl: 0.99, 0.97-0.99, p = 0.040) remained independently associated with the composite endpoint on multivariate Cox regression analysis.

Conclusions

Complement levels and immunoglobulins may serve as surrogates of cirrhosis-associated immune dysfunction and associate with cirrhosis severity and systemic inflammation. Low complement C3c predicted decompensation and liver-related death, whereas high IgG-1 indicated an increased risk for infections.

Impact and Implications

Patients with cirrhosis are at increased risk for infections, which worsen their prognosis. We found a significant dysregulation of several essential components of the immune system that was linked to disease severity and indicated a risk for infections and other complications. Simple blood tests identify patients at particularly high risk, who may be candidates for preventive measures.

Clinical Trials Registration

This study is registered at ClinicalTrials.gov (NCT03267615).

Gut Microbiota and Infectious Complications in Advanced Chronic Liver Disease: Focus on Spontaneous Bacterial Peritonitis

Liver cirrhosis is a chronic disease that can be complicated by episodes of decompensation such as variceal bleeding, hepatic encephalopathy, ascites, and jaundice, with subsequent increased mortality. Infections are also among the most common complications in cirrhotic patients, mostly due to a defect in immunosurveillance. Among them, one of the most frequent is spontaneous bacterial peritonitis (SBP), defined as the primary infection of ascitic fluid without other abdominal foci. SBP is mainly induced by Gram-negative bacteria living in the intestinal tract, and translocating through the intestinal barrier, which in cirrhotic patients is defective and more permeable. Moreover, in cirrhotic patients, the intestinal microbiota shows an altered composition, poor in beneficial elements and enriched in potentially pathogenic ones. This condition further promotes the development of leaky gut and increases the risk of SBP. The first-line treatment of SBP is antibiotic therapy; however, the antibiotics used have a broad spectrum of action and may adversely affect the composition of the gut microbiota, worsening dysbiosis. For this reason, the future goal is to use new therapeutic agents that act primarily on the gut microbiota, selectively modulating it, or on the intestinal barrier, reducing its permeability. In this review, we aim to describe the reciprocal relationship between gut microbiota and SBP, focusing on pathogenetic aspects but also on new future therapies.

Assessment of neutrophil subsets and immune checkpoint inhibitor expressions on T lymphocytes in liver transplantation: A preliminary study beyond the neutrophil-lymphocyte ratio

Background: Advanced stages of cirrhosis are characterized by the occurrence of progressive immune alterations known as CAID (Cirrhosis Associated Immune Dysfunction). In advanced cirrhosis, liver transplantation (LT) remains the only curative treatment. Sepsis, shares many similarities with decompensated cirrhosis in terms of immuno-inflammatory response. In both conditions, the neutrophil-lymphocyte ratio (NLR) is associated with poor outcomes. Based on alterations in sepsis, we hypothesized that we could observe in cirrhotic and LT patients more detailed neutrophil and lymphocyte phenotypes. To this end, along with leukocyte count, we assessed immature neutrophils, LOX-1⁺ MDSC and PD-1 and TIM-3 lymphocyte expressions in cirrhotic patients before transplantation in association with liver disease severity and during the first month after transplantation. Methods: We conducted a prospective monocentric study including cirrhotic patients registered on LT waiting-list. Blood samples were collected at enrolment before LT and for 1 month post-LT. In addition to NLR, we assessed by whole blood flow cytometry the absolute count of immature neutrophils and LOX-1⁺ MDSC as well as the expressions of immune checkpoint receptors PD-1 and TIM-3 on T lymphocytes. Results: We included 15 healthy volunteers (HV) and 28 patients. LT was performed for 13 patients. Pre-LT patients presented with a higher NLR compared to HV and NLR was associated with cirrhosis severity. Increased immature neutrophils and LOX-1⁺ MDSC counts were observed in the most severe patients. These alterations were mainly associated with acute decompensation of cirrhosis. PD-1 and TIM-3 expressions on T lymphocytes were not different between patients and HV. Post-LT immune alterations were dominated by a transitory but tremendous increase of NLR and immature neutrophils during the first days post-LT. Then, immune checkpoint receptors and LOX-1⁺ MDSC tended to be overexpressed by the second week after surgery. Conclusion: The present study showed that NLR, immature neutrophils and LOX-1⁺ MDSC counts along with T lymphocyte count and checkpoint inhibitor expression were altered in cirrhotic patients before and after LT. These data illustrate the potential interest of immune monitoring of cirrhotic patients in the context of LT in order to better define risk of sepsis. For this purpose, larger cohorts of patients are now necessary in order to move forward a more personalised care of LT patients.

The benefit of immunotherapy in patients with hepatocellular carcinoma: a systematic review and meta-analysis

Background: A systemic review of the survival benefit of immune checkpoint inhibitors (ICIs) in phase III hepatocellular carcinoma (HCC) trials was conducted. Methods: Meta-analyses were performed with the generic inverse-variance method with a fixed-effects model. Results: In 10 trials encompassing 6123 patients, ICI-based therapy (monotherapy/combination) improved overall survival (OS) compared with the control arm (hazard ratio [HR]: 0.77; 95% CI: 0.70-0.84; p < 0.001). The survival benefit was consistent across variable treatment lines, Eastern Cooperative Oncology Group performance status and AFP levels. While the OS benefit was more pronounced in hepatitis B-related HCC (HR: 0.70; 95% CI: 0.63-0.77; p < 0.001), OS was improved in hepatitis C-related (HR: 0.83; 95% CI: 0.71-0.98) and nonviral HCC (HR: 0.86; 95% CI: 0.77-0.97). Conclusion: ICI-based therapies should be the standard for all patients with advanced HCC.

COVID-19 Vaccination in Patients with Chronic Liver Disease

Vaccination against SARS-CoV-2 has become a central public health issue, primarily for vulnerable populations such as individuals with Chronic Liver Disease (CLD). Increased COVID-19-related mortality and disease severity has been noted in this subgroup of patients. Severe COVID-19 tends to further deregulate liver function in patients with chronic liver failure or cirrhosis and even reactivate hepatitis in people living with HBV or HCV. In addition, impaired hepatic function leads to several limitations in possible therapeutic interventions. Chronic hepatic dysregulation, along with the underlying cirrhosis-associated immune dysfunction (CAID), leads to a decreased immune response to vaccination that, in turn, may result in reduced efficacy rates and lowered lasting protection. According to current guidelines, timely vaccination and frequent booster shot administration are deemed necessary in this context. Vaccination-related adverse events are mostly mild in nature and similar to those reported in the general population, whereas the incidence of liver injury following vaccination is relatively rare. We aimed to review available evidence and recommendations associated with COVID-19 vaccination in patients with chronic liver disease, and provide insight to current issues and future directions.

New-onset and relapsed liver diseases following COVID-19 vaccination: a systematic review

BACKGROUND

Liver diseases post-COVID-19 vaccination is extremely rare but can occur. A growing body of evidence has indicated that portal vein thrombosis, autoimmune hepatitis, raised liver enzymes and liver injuries, etc., may be potential consequence of COVID-19 vaccines.

OBJECTIVES

To describe the results of a systematic review for new-onset and relapsed liver disease following COVID-19 vaccination.

METHODS

For this systematic review, we searched Proquest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature through the Preferred Reporting Items for Systematic Reviews and Meta Analyses PRISMA guideline for studies on the incidence of new onset or relapsed liver diseases post-COVID-19 vaccination, published from December 1, 2020 to July 31, 2022, with English language restriction.

RESULTS

Two hundred seventy-five cases from one hundred and eighteen articles were included in the qualitative synthesis of this systematic review. Autoimmune hepatitis (138 cases) was the most frequent pathology observed post-COVID-19 vaccination, followed by portal vein thrombosis (52 cases), raised liver enzymes (26 cases) and liver injury (21 cases). Other cases include splanchnic vein thrombosis, acute cellular rejection of the liver, jaundice, hepatomegaly, acute hepatic failure and hepatic porphyria. Mortality was reported in any of the included cases for acute hepatic failure (n = 4, 50%), portal vein thrombosis (n = 25, 48.1%), splanchnic vein thrombosis (n = 6, 42.8%), jaundice (n = 1, 12.5%), raised liver enzymes (n = 2, 7.7%), and autoimmune hepatitis (n = 3, 2.2%). Most patients were easily treated without any serious complications, recovered and did not require long-term hepatic therapy.

CONCLUSION

Reported evidence of liver diseases post-COIVD-19 vaccination should not discourage vaccination against this worldwide pandemic. The number of reported cases is relatively very small in relation to the hundreds of millions of vaccinations that have occurred and the protective benefits offered by COVID-19 vaccination far outweigh the risks.

The gut-liver axis in immune remodeling of hepatic cirrhosis

In healthy settings, the gut-liver axis allows host-microbiota communications and mediates immune homeostasis through bidirectional regulation. Meanwhile, in diseases, gut dysbiosis, combined with an impaired intestinal barrier, introduces pathogens and their toxic metabolites into the system, causing massive immune alternations in the liver and other extrahepatic organs. Accumulating evidence suggests that these immune changes are associated with the progression of many liver diseases, especially hepatic cirrhosis. Pathogen-associated molecular patterns that originated from gut microbes directly stimulate hepatocytes and liver immune cells through different pattern recognition receptors, a process further facilitated by damage-associated molecular patterns released from injured hepatocytes. Hepatic stellate cells, along with other immune cells, contribute to this proinflammatory and profibrogenic transformation. Moreover, cirrhosis-associated immune dysfunction, an imbalanced immune status characterized by systemic inflammation and immune deficiency, is linked to gut dysbiosis. Though the systemic inflammation hypothesis starts to link gut dysbiosis to decompensated cirrhosis from a clinical perspective, a clearer demonstration is still needed for the role of the gut-liver-immune axis in cirrhosis progression. This review discusses the different immune states of the gut-liver axis in both healthy and cirrhotic settings and, more importantly, summarizes the current evidence about how microbiota-derived immune remodeling contributes to the progression of hepatic cirrhosis via the gut-liver axis.

Plasticity of monocytes and macrophages in cirrhosis of the liver

Cirrhosis of the liver is a systemic condition with raising prevalence worldwide. Patients with cirrhosis are highly susceptible to develop bacterial infections leading to acute decompensation and acute-on-chronic liver failure both associated with a high morbidity and mortality and sparse therapeutic options other than transplantation. Mononuclear phagocytes play a central role in innate immune responses and represent a first line of defence against pathogens. Their function includes phagocytosis, killing of bacteria, antigen presentation, cytokine production as well as recruitment and activation of immune effector cells. Liver injury and development of cirrhosis induces activation of liver resident Kupffer cells and recruitment of monocytes to the liver. Damage- and pathogen-associated molecular patterns promote systemic inflammation which involves multiple compartments besides the liver, such as the circulation, gut, peritoneal cavity and others. The function of circulating monocytes and tissue macrophages is severely impaired and worsens along with cirrhosis progression. The underlying mechanisms are complex and incompletely understood. Recent 'omics' technologies help to transform our understanding of cellular diversity and function in health and disease. In this review we point out the current state of knowledge on phenotypical and functional changes of monocytes and macrophages during cirrhosis evolution in different compartments and their role in disease progression. We also discuss the value of potential prognostic markers for cirrhosis-associated immuneparesis, and future immunotherapeutic strategies that may reduce the need for transplantation and death.

Immune Alterations in a Patient With Hyperornithinemia-Hyperammonemia-Homocitrullinuria Syndrome: A Case Report

The hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive inborn error of the urea cycle caused by mutations in the SLC25A15 gene. Besides the well-known metabolic complications, patients often present intercurrent infections associated with acute hyperammonemia and metabolic decompensation. However, it is currently unknown whether intercurrent infections are associated with immunological alterations besides the known metabolic imbalances. Herein, we describe the case of a 3-years-old girl affected by the HHH syndrome caused by two novel SLC25A15 gene mutations associated with immune phenotypic and functional alterations. She was admitted to the hospital with an episode of recurrent otitis, somnolence, confusion, and lethargy. Laboratory tests revealed severe hyperammonemia, elevated serum levels of liver transaminases, hemostasis alterations, hyperglutaminemia and strikingly increased orotic aciduria. Noteworthy, serum protein electrophoresis showed a reduction in the gamma globulin fraction. Direct sequencing of the SLC25A15 gene revealed two heterozygous non-conservative substitutions in the exon 5: c.649G>A (p.Gly217Arg) and c.706A>G (p.Arg236Gly). In silico analysis indicated that both mutations significantly impair protein structure and function and are consistent with the patient clinical status confirming the diagnosis of HHH syndrome. In addition, the immune analysis revealed reduced levels of serum IgG and striking phenotypic and functional alterations in the T and B cell immune compartments. Our study has identified two non-previously described mutations in the SLC25A15 gene underlying the HHH syndrome. Moreover, we are reporting for the first time functional and phenotypic immunologic alterations in this rare inborn error of metabolism that would render the patient immunocompromised and might be related to the high frequency of intercurrent infections observed in patients bearing urea cycle disorders. Our results point out the importance of a comprehensive analysis to gain further insights into the underlying pathophysiology of the disease that would allow better patient care and quality of life.

Phenotypical changes and clinical significance of CD4+/CD8+ T cells in SLE

OBJECTIVE

T cells display significant phenotypical changes and play multiple roles in promoting the immune response in SLE. The frequencies of T cell subpopulations in SLE are still not well understood. To better understanding the phenotypic abnormalities of T cells in SLE will help us to clarify disease immunopathology and to find promising biomarkers for disease monitoring and control.

METHODS

Peripheral blood CD4⁺ and CD8⁺ T cells and their subsets were determined by flow cytometry. Forty-one active SLE patients were selected, including 28 new-onset patients and 13 relapsing patients. One hundred healthy controls (HCs) were enrolled as the control group. The percentages of these cell subsets between patients with SLE and HCs and their relationships with disease activity and autoantibody titers were analysed. Thirteen of 28 new-onset SLE patients were assessed before and after treatment. The changes in the frequencies of these cell subsets and their relationships with renal response were analysed.

RESULTS

There was a broad range of anomalies in the proportion of T cell subsets in patients with SLE compared with that of the HCs. Compared with the HCs, a higher frequency of memory T cells and a lower frequency of naïve T cells were noted in patients with SLE. In addition, an imbalance of CD28⁺ and CD28^- cells in CD4⁺ T cells was observed in patients with SLE. We found that the expanded CD4⁺CD28^- T cells did not decrease after treatment in patients who had impaired renal responses. It was very interesting to exhibit a negative correlation in the frequency between the CD4⁺CD28^- T cells and T regulatory (Treg) cells and a positive correlation between the frequency of CD4⁺CD28⁺ T cells and Treg cells in this study. Increased CD8⁺HLADR⁺ T cell and CD8⁺CD38⁺HLADR⁺ T cell counts were observed in patients with SLE, suggesting an impaired cytotoxic capacity of CD8⁺ T cells in SLE. Additionally, we found that CD8⁺CD38⁺HLADR⁺ T cells were closely associated with disease activity, autoantibody titres and renal prognosis. CD4⁺ CXCR5^-PD1⁺ T cells were expanded in patients with SLE in this study and were associated with disease activity in SLE. Th1 (T helper type 1) cells and Treg cells were decreased, but frequencies of T follicular helper (Tfh) cells, Th2 cells, Th17 cells and Tfh17 cells were increased. A strong correlation between Th17 cells and Tregs with renal involvement was observed in this study.

CONCLUSION

The proportions of CD4⁺CD28^- T cells, CD4⁺CXCR5^-PD1⁺ T cells, CD8⁺HLADR⁺ T cells and CD8⁺CD38⁺HLADR⁺ T cells increased in patients with SLE and could be associated with disease activity and renal prognosis.

Suppressor CD4+ T cells expressing HLA-G are expanded in the peripheral blood from patients with acute decompensation of cirrhosis

OBJECTIVE

Identifying components of immuneparesis, a hallmark of chronic liver failure, is crucial for our understanding of complications in cirrhosis. Various suppressor CD4⁺ T cells have been established as potent inhibitors of systemic immune activation. Here, we establish the presence, regulation and mechanism of action of a suppressive CD4⁺ T cell subset expressing human leucocyte antigen G (HLA-G) in patients with acute decompensation of cirrhosis (AD).

DESIGN

Flow cytometry was used to determine the proportion and immunophenotype of CD4⁺HLA-G⁺ T cells from peripheral blood of 20 healthy controls (HCs) and 98 patients with cirrhosis (28 with stable cirrhosis (SC), 20 with chronic decompensated cirrhosis (CD) and 50 with AD). Transcriptional and functional signatures of cell-sorted CD4⁺HLA-G⁺ cells were delineated by NanoString technology and suppression assays, respectively. The role of immunosuppressive cytokine interleukin (IL)-35 in inducing this population was investigated through in vitro blockade experiments. Immunohistochemistry (IHC) and cultures of primary human Kupffer cells (KCs) were performed to assess cellular sources of IL-35. HLA-G-mediated T cell suppression was explored using neutralising antibodies targeting co-inhibitory pathways.

RESULTS

Patients with AD were distinguished by an expansion of a CD4⁺HLA-G⁺CTLA-4⁺IL-35⁺ immunosuppressive population associated with disease severity, clinical course of AD, infectious complications and poor outcome. Transcriptomic analyses excluded the possibility that these were thymic-derived regulatory T cells. IHC analyses and in vitro cultures demonstrate that KCs represent a potent source of IL-35 which can induce the observed HLA-G⁺ phenotype. These exert cytotoxic T lymphocyte antigen-4-mediated impaired responses in T cells paralleled by an HLA-G-driven downregulation of T helper 17-related cytokines.

CONCLUSION

We have identified a cytokine-driven peripherally derived suppressive population that may contribute to immuneparesis in AD.

Increase in Serum Soluble Tim-3 Level Is Related to the Progression of Diseases After Hepatitis Virus Infection

Background

Viral hepatitis is a widespread and serious infectious disease, and most patients with liver cirrhosis and hepatocellular carcinoma are prone to viral infections. T cell immunoglobulin-and mucin-domain-containing molecule-3 (Tim-3) is an immune checkpoint molecule that negatively regulates T cell responses, playing an extremely important role in controlling infectious diseases. However, reports about the role of serum soluble Tim-3 (sTim-3) in hepatitis virus infection are limited. Therefore, this study explored changes in sTim-3 levels in patients infected with hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV).

Methods

This study applied high-sensitivity time-resolved fluorescence immunoassay for the detection of sTim-3 levels. A total of 205 cases of viral hepatitis infection (68 cases of HBV infection, 60 cases of HCV infection, and 77 cases of HEV virus infection) and 88 healthy controls were quantitatively determined. The changes in serum sTim-3 level and its clinical value in hepatitis virus infection were analyzed.

Results

Patients with HBV infection (14.00, 10.78–20.45 ng/mL), HCV infection (15.99, 11.83–27.00 ng/mL), or HEV infection (19.09, 10.85–33.93 ng/mL) had significantly higher sTim-3 levels than that in the healthy control group (7.69, 6.14–10.22 ng/mL, P &lt; 0.0001). Patients with hepatitis and fibrosis infected with HBV (22.76, 12.82–37.53 ng/mL), HCV (33.06, 16.36–39.30 ng/mL), and HEV (28.90, 17.95–35.94 ng/mL) had significantly higher sTim-3 levels than patients with hepatitis without fibrosis (13.29, 7.75–17.28; 13.86, 11.48–18.64; 14.77, 9.79–29.79 ng/mL; P &lt; 0.05).

Conclusion

sTim-3 level was elevated in patients infected with HBV, HCV, or HEV and gradually increased in patients with either hepatitis or hepatitis with hepatic fibrosis. It has a certain role in the evaluation of the course of a disease after hepatitis virus infection.

Implications and Management of Cirrhosis-Associated Immune Dysfunction Before and After Liver Transplantation

Cirrhosis-associated immune dysfunction (CAID) describes a panacea of innate and adaptive deficits that result from the sequelae of cirrhotic portal hypertension that is similar in its manifestations regardless of etiology of chronic liver injury. CAID is associated with synchronous observations of dysregulated priming of innate immune effector cells that demonstrate a proinflammatory phenotype but are functionally impaired and unable to adequately prevent invading pathogens. CAID is mainly driven by gut-barrier dysfunction and is associated with deficits of microbial compartmentalization and homeostasis that lead to tonic activation, systemic inflammation, and exhaustion of innate-immune cells. CAID leads to a high frequency of bacterial and fungal infections in patients with cirrhosis that are often associated with acute decompensation of chronic liver disease and acute-on-chronic liver failure and carry a high mortality rate. Understanding the deficits of mucosal and systemic immunity in the context of chronic liver disease is essential to improving care for patients with cirrhosis, preventing precipitants of acute decompensation of cirrhosis, and improving morbidity and survival. In this review, we summarize the detailed dynamic immunological perturbations associated with advanced chronic liver disease and highlight the importance of recognizing immune dysregulation as a sequela of cirrhosis. Furthermore, we address the role of screening, prevention, and early treatment of infections in cirrhosis in improving patient outcomes in transplant and nontransplant settings.

SARS-CoV-2 Infections Among Patients With Liver Disease and Liver Transplantation Who Received COVID-19 Vaccination

Many safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinations dramatically reduce risks of coronavirus disease 2019 (COVID-19) complications and deaths. We aimed to describe cases of SARS-CoV-2 infection among patients with chronic liver disease (CLD) and liver transplant (LT) recipients with at least one prior COVID-19 vaccine dose. The SECURE-Liver and COVID-Hep international reporting registries were used to identify laboratory-confirmed COVID-19 in CLD and LT patients who received a COVID-19 vaccination. Of the 342 cases of lab-confirmed SARS-CoV-2 infections in the era after vaccine licensing, 40 patients (21 with CLD and 19 with LT) had at least one prior COVID-19 vaccination, including 12 who were fully vaccinated (≥2 weeks after second dose). Of the 21 patients with CLD (90% with cirrhosis), 7 (33%) were hospitalized, 1 (5%) was admitted to the intensive care unit (ICU), and 0 died. In the LT cohort (n = 19), there were 6 hospitalizations (32%), including 3 (16%) resulting in mechanical ventilation and 2 (11%) resulting in death. All three cases of severe COVID-19 occurred in patients who had a single vaccine dose within the last 1-2 weeks. In contemporary patients with CLD, rates of symptomatic infection, hospitalization, ICU admission, invasive ventilation, and death were numerically higher in unvaccinated individuals. Conclusion: This case series demonstrates the potential for COVID-19 infections among patients with CLD and LT recipients who had received the COVID-19 vaccination. Vaccination against SARS-CoV-2 appears to result in favorable outcomes as attested by the absence of mechanical ventilation, ICU, or death among fully vaccinated patients.

Impaired SARS-CoV-2-specific T cell reactivity in patients with cirrhosis following mRNA COVID-19 vaccination

Background & Aims

Cirrhosis entails elevated risk of COVID-19-associated mortality. This study determined T cell-mediated and antibody reactivity against the spike 1 (S1) protein of SARS-CoV-2 among 48 patients with cirrhosis and 39 healthy controls after mRNA COVID-19 vaccination.

Methods

SARS-CoV-2-specific T-cell reactivity was measured by induced level of T cell-derived interferon-γ (IFN-γ) in blood cells stimulated ex vivo with multimeric peptides spanning the N-terminal portion of S1. S1-induced IFN-γ was quantified before and after the 1^st and 2^nd vaccination (BNT162b2, Pfizer-BioNTech or mRNA-1273, Moderna) alongside serum IgG against the receptor-binding domain (RBD) within S1 (anti-RBD-S1 IgG).

Results

T-cell reactivity against S1 was reduced in patients with cirrhosis after the 1^st (p <0.001 vs. controls) and 2^nd (p <0.001) vaccination. Sixty-eight percent of patients lacked detectable S1-specific T-cell reactivity after the 1^st vaccination vs. 19% in controls (odds ratio 0.11, 95% CI 0.03-0.48, p = 0.003) and 36% remained devoid of reactivity after the 2^nd vaccination vs. 6% in controls (odds ratio 0.12, 95% CI 0.03-0.59, p = 0.009). T-cell reactivity in cirrhosis remained significantly impaired after correction for potential confounders in multivariable analysis. Advanced cirrhosis (Child-Pugh class B) was associated with absent or lower T-cell responses (p <0.05 vs. Child-Pugh class A). The deficiency of T-cell reactivity was paralleled by lower levels of anti-RBD-S1 IgG after the 1^st (p <0.001 vs. controls) and 2^nd (p <0.05) vaccination.

Conclusions

Patients with cirrhosis show deficient T-cell reactivity against SARS-CoV-2 antigens along with diminished levels of anti-RBD-S1 IgG after dual COVID-19 vaccination, highlighting the need for vigilance and additional preventative measures.

Clinical trial registration

EudraCT 2021-000349-42

Lay summary

T cells are a pivotal component in the defence against viruses. We show that patients with cirrhosis have impaired SARS-CoV-2-specific T-cell responses and lower antibody levels after mRNA vaccination against COVID-19 compared with healthy controls. Patients with more advanced liver disease exhibited particularly inferior vaccine responses. These results call for additional preventative measures in these patients.

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After COVID-19 vaccination, patients with cirrhosis had impaired T-cell and antibody responses.

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Child-Pugh class B cirrhosis was associated with poorer immune responses than class A.

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Multivariate analyses excluded potential confounding variables.

Gut-derived systemic inflammation as a driver of depression in chronic liver disease

Depression and chronic liver disease (CLD) are important causes of disability, morbidity and mortality worldwide and their prevalence continues to rise. The rate of depression in CLD is high compared to that of the general population and is comparable to the increased rates observed in other medical comorbidities and chronic inflammatory conditions. Notably, a comorbid diagnosis of depression has a detrimental effect on outcomes in cirrhosis. Systemic inflammation is pivotal in cirrhosis-associated immune dysfunction - a phenomenon present in advanced CLD (cirrhosis) and implicated in the development of complications, organ failure, disease progression, increased infection rates and poor outcome. The presence of systemic inflammation is also well-documented in a cohort of patients with depression; peripheral cytokine signals can result in neuroinflammation, behavioural change and depressive symptoms via neural mechanisms, cerebral endothelial cell and circumventricular organ signalling, and peripheral immune cell-to-brain signalling. Gut dysbiosis has been observed in both patients with cirrhosis and depression. It leads to intestinal barrier dysfunction resulting in increased bacterial translocation, in turn activating circulating immune cells, leading to cytokine production and systemic inflammation. A perturbed gut-liver-brain axis may therefore explain the high rates of depression in patients with cirrhosis. The underlying mechanisms explaining the critical relationship between depression and cirrhosis remain to be fully elucidated. Several other psychosocial and biological factors are likely to be involved, and therefore the cause is probably multifactorial. However, the role of the dysfunctional gut-liver-brain axis as a driver of gut-derived systemic inflammation requires further exploration and consideration as a target for the treatment of depression in patients with cirrhosis.

Cirrhosis-associated immune dysfunction

The term cirrhosis-associated immune dysfunction (CAID) comprises the distinctive spectrum of immune alterations associated with the course of end-stage liver disease. Systemic inflammation and immune deficiency are the key components of CAID. Their severity is highly dynamic and progressive, paralleling cirrhosis stage. CAID involves two different immune phenotypes: the low-grade systemic inflammatory phenotype and the high-grade systemic inflammatory phenotype. The low-grade systemic inflammatory phenotype can be found in patients with compensated disease or clinical decompensation with no organ failure. In this phenotype, there is an exaggerated immune activation but the effector response is not markedly compromised. The high-grade systemic inflammatory phenotype is present in patients with acute-on-chronic liver failure, a clinical situation characterized by decompensation, organ failure and high short-term mortality. Along with high-grade inflammation, this CAID phenotype includes intense immune paralysis that critically increases the risk of infections and worsens prognosis. The intensity of CAID has important consequences on cirrhosis progression and correlates with the severity of liver insufficiency, bacterial translocation and organ failure. Therapies targeting the modulation of the dysfunctional immune response are currently being evaluated in preclinical and clinical studies.

Immune Microenvironment Characteristics of Urachal Carcinoma and Its Implications for Prognosis and Immunotherapy

Urachal carcinoma (UrC) is an exceedingly rare tumor and lacks effective treatment. Herein, we characterized an immune microenvironment characteristic of UrC in detail and identified its implications for prognosis and immunotherapy. In total, 37 resections of UrC were stained for CD20, CD3, CD4, CD8, FOXP3, CD68, HLA-DR, CD163, PD1, and PD-L1, as well as mismatch repair protein including MSH2, MSH6, MLH1, and PMS2 by immunohistochemistry. Intratumoral and peritumoral immune cell densities or the proportion of PD1 and PD-L1 expression alongside MSH2, MSH6, MLH1, and PMS2 status were manually evaluated using the whole slide. UrC patients with the number of tertiary lymphoid structures (TLS) per slide tended to be higher in tumors with dMMR (p = 0.1919), and tumors with higher number of TLS tended to have longer OS (p = 0.0940) and DFS (p = 0.0700). High densities of CD3+ T, CD8+ T, and CD68+ cells were significantly associated with worse OS and DFS (both p<0.05). Increased intratumoral (p = 0.0111) and peritumoral (p = 0.0485) CD8+ T cell densities were significantly associated with PD-L1 expression or increasing proportion of PD-L1 expression on immune cells. Similarly, increased intratumoral (p = 0.0008) and peritumoral (p = 0.063) CD8+ T cell densities were significantly associated with increasing proportion of PD1 expression on immune cells. Tumors with PD-L1 positive expression on immune cells had a significantly increased proportion of PD1 expression (p = 0.0121). High peritumoral CD8+ T cell density (>73.7/mm²) was significantly associated with worse OS (p = 0.0120) and DFS (p = 0.00095). The number of TLS seems to be considered not only as histopathological characteristics in predicting MMR status of UrC, but also as a prognostic or therapeutic biomarker, and we also provide some important suggestions for targeting PD-1/PD-L1 checkpoint in UrC.

Current Perspectives on the Immunosuppressive Niche and Role of Fibrosis in Hepatocellular Carcinoma and the Development of Antitumor Immunity

Immune checkpoint inhibitors have become the mainstay of treatment for hepatocellular carcinoma (HCC). However, they are ineffective in some cases. Previous studies have reported that genetic alterations in oncogenic pathways such as Wnt/β-catenin are the important triggers in HCC for primary refractoriness. T-cell exhaustion has been reported in various tumors and is likely to play a prominent role in the emergence of HCC due to chronic inflammation and cirrhosis-associated immune dysfunction. Immunosuppressive cells including regulatory T-cells and tumor-associated macrophages infiltrating the tumor are associated with hyperprogressive disease in the early stages of immune checkpoint inhibitor treatment. In addition, stellate cells and tumor-associated fibroblasts create an abundant desmoplastic environment by producing extracellular matrix. This strongly contributes to epithelial to mesenchymal transition via signaling activities including transforming growth factor beta, Wnt/β-catenin, and Hippo pathway. The abundant desmoplastic environment has been demonstrated in pancreatic ductal adenocarcinoma and cholangiocarcinoma to suppress cytotoxic T-cell infiltration, PD-L1 expression, and neoantigen expression, resulting in a highly immunosuppressive niche. It is possible that a similar immunosuppressive environment is created in HCC with advanced fibrosis in the background liver. Although sufficient understanding is required for the establishment of immune therapies of HCC, further investigations are still required in this field.

Critical Update on the Diagnosis and Management of COVID-19 in Advanced Cirrhosis and Liver Transplant Recipients

The novel coronavirus disease 2019 (COVID-19) pandemic has impacted health care worldwide, with specific patient populations, such as those with diabetes, cardiovascular disease, and chronic lung disease, at higher risk of infection and others at higher risk of disease progression. Patients with decompensated cirrhosis fall into the latter category and are a unique group that require specific treatment and management decisions because they can develop acute-on-chronic liver failure. In liver transplant recipients, the atypical immunity profile due to immunosuppression protects against downstream inflammatory responses triggered by COVID-19. This exhaustive review discusses the outcomes associated with COVID-19 in patients with advanced cirrhosis and in liver transplant recipients. We focus on the immunopathogenesis of COVID-19, its correlation with the pathogenesis of advanced liver disease, and the effect of immunosuppression in liver transplant recipients to provide insight into the outcomes of this unique patient population.