Efficient presentation of exogenous antigen by liver endothelial cells to CD8+ T cells results in antigen-specific T-cell tolerance

Targeting the tumour vasculature: from vessel destruction to promotion

As angiogenesis was recognized as a core hallmark of cancer growth and survival, several strategies have been implemented to target the tumour vasculature. Yet to date, attempts have rarely been so diverse, ranging from vessel growth inhibition and destruction to vessel normalization, reprogramming and vessel growth promotion. Some of these strategies, combined with standard of care, have translated into improved cancer therapies, but their successes are constrained to certain cancer types. This Review provides an overview of these vascular targeting approaches and puts them into context based on our subsequent improved understanding of the tumour vasculature as an integral part of the tumour microenvironment with which it is functionally interlinked. This new knowledge has already led to dual targeting of the vascular and immune cell compartments and sets the scene for future investigations of possible alternative approaches that consider the vascular link with other tumour microenvironment components for improved cancer therapy.

Causal association between 731 immunocyte phenotypes and liver cirrhosis: A bidirectional two-sample mendelian randomization analysis

BACKGROUND

Liver cirrhosis is a progressive hepatic disease whose immunological basis has attracted increasing attention. However, it remains unclear whether a concrete causal association exists between immunocyte phenotypes and liver cirrhosis.

AIM

To explore the concrete causal relationships between immunocyte phenotypes and liver cirrhosis through a mendelian randomization (MR) study.

METHODS

Data on 731 immunocyte phenotypes were obtained from genome-wide association studies. Liver cirrhosis data were derived from the Finn Gen dataset, which included 214403 individuals of European ancestry. We used inverse variable weighting as the primary analysis method to assess the causal relationship. Sensitivity analyses were conducted to evaluate heterogeneity and horizontal pleiotropy.

RESULTS

The MR analysis demonstrated that 11 immune cell phenotypes have a positive association with liver cirrhosis [P < 0.05, odds ratio (OR) > 1] and that 9 immunocyte phenotypes were negatively correlated with liver cirrhosis (P < 0.05, OR < 1). Liver cirrhosis was positively linked to 9 immune cell phenotypes (P < 0.05, OR > 1) and negatively linked to 10 immune cell phenotypes (P < 0.05; OR < 1). None of these associations showed heterogeneity or horizontally pleiotropy (P > 0.05).

CONCLUSION

This bidirectional two-sample MR study demonstrated a concrete causal association between immunocyte phenotypes and liver cirrhosis. These findings offer new directions for the treatment of liver cirrhosis.

A liver immune rheostat regulates CD8 T cell immunity in chronic HBV infection

Chronic hepatitis B virus (HBV) infection affects 300 million patients worldwide1,2, in whom virus-specific CD8 T cells by still ill-defined mechanisms lose their function and cannot eliminate HBV-infected hepatocytes3-7. Here we demonstrate that a liver immune rheostat renders virus-specific CD8 T cells refractory to activation and leads to their loss of effector functions. In preclinical models of persistent infection with hepatotropic viruses such as HBV, dysfunctional virus-specific CXCR6+ CD8 T cells accumulated in the liver and, as a characteristic hallmark, showed enhanced transcriptional activity of cAMP-responsive element modulator (CREM) distinct from T cell exhaustion. In patients with chronic hepatitis B, circulating and intrahepatic HBV-specific CXCR6+ CD8 T cells with enhanced CREM expression and transcriptional activity were detected at a frequency of 12-22% of HBV-specific CD8 T cells. Knocking out the inhibitory CREM/ICER isoform in T cells, however, failed to rescue T cell immunity. This indicates that CREM activity was a consequence, rather than the cause, of loss in T cell function, further supported by the observation of enhanced phosphorylation of protein kinase A (PKA) which is upstream of CREM. Indeed, we found that enhanced cAMP-PKA-signalling from increased T cell adenylyl cyclase activity augmented CREM activity and curbed T cell activation and effector function in persistent hepatic infection. Mechanistically, CD8 T cells recognizing their antigen on hepatocytes established close and extensive contact with liver sinusoidal endothelial cells, thereby enhancing adenylyl cyclase-cAMP-PKA signalling in T cells. In these hepatic CD8 T cells, which recognize their antigen on hepatocytes, phosphorylation of key signalling kinases of the T cell receptor signalling pathway was impaired, which rendered them refractory to activation. Thus, close contact with liver sinusoidal endothelial cells curbs the activation and effector function of HBV-specific CD8 T cells that target hepatocytes expressing viral antigens by means of the adenylyl cyclase-cAMP-PKA axis in an immune rheostat-like fashion.

Anti-PD-1 alone or in combination with anti-CTLA-4 for advanced melanoma patients with liver metastases

BACKGROUND

The combination of anti-PD-1 and anti-CTLA-4 has been associated with improvement in response and survival over anti-PD-1 monotherapy in unselected patients with advanced melanoma. Whether patients with liver metastases also benefit from the combination of anti-PD-1 and anti-CTLA-4 over anti-PD-1, is unclear. In this study, we sought to assess whether the combination of anti-PD-1 and anti-CTLA-4 leads to better response, progression-free survival and overall survival, compared with anti-PD-1 monotherapy for patients with liver metastases.

METHODS

We have conducted an international multicentre retrospective study. Patients with advanced melanoma with liver metastases treated with 1st line anti-PD1 monotherapy or with anti-CTLA-4 were included. The endpoints of this study were: objective response rate, progression-free survival and overall survival.

RESULTS

With a median follow-up from commencement of anti-PD-1 monotherapy or in combination with anti-CTLA-4 of 47 months (95% CI, 42-51), objective response rate was higher with combination therapy (47%) versus anti-PD-1 monotherapy (35%) (p = 0.0027), while progression-free survival and overall survival were not statistically different between both treatment groups. However, on multivariable analysis with multiple imputation for missing values and adjusting for predefined variables, combination of anti-PD1 and anti-CTLA-4 was associated with higher objective response (OR 2.21, 1.46 - 3.36; p < 0.001), progression-free survival (HR 0.73, 0.57 - 0.92; p = 0.009) and overall survival (HR 0.71, 0.54 - 0.94; p = 0.018) compared to anti-PD1 monotherapy.

CONCLUSIONS

Findings from this study will help guide treatment selection for patients who present with liver metastases, suggesting that combination therapy should be considered for this group of patients.

Role of liver sinusoidal endothelial cell in metabolic dysfunction-associated fatty liver disease

Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells that represent the interface between blood cells on one side and hepatocytes on the other side. LSECs not only form a barrier within the hepatic sinus, but also play important physiological functions such as regulating hepatic vascular pressure, anti-inflammatory and anti-fibrotic. Pathologically, pathogenic factors can induce LSECs capillarization, that is, loss of fenestra and dysfunction, which are conducive to early steatosis, lay the foundation for the progression of metabolic dysfunction-associated fatty liver disease (MAFLD), and accelerate metabolic dysfunction-associated steatohepatitis (MASH) and liver fibrosis. The unique localization, phenotype, and function of LSECs make them potential candidates for reducing liver injury, inflammation, and preventing or reversing fibrosis in the future.

Τ cell-mediated adaptive immunity in the transition from metabolic dysfunction-associated steatohepatitis to hepatocellular carcinoma

Metabolic dysfunction-associated steatohepatitis (MASH) is the progressed version of metabolic dysfunction-associated steatotic liver disease (MASLD) characterized by inflammation and fibrosis, but also a pathophysiological "hub" that favors the emergence of liver malignancies. Current research efforts aim to identify risk factors, discover disease biomarkers, and aid patient stratification in the context of MASH-induced hepatocellular carcinoma (HCC), the most prevalent cancer among MASLD patients. To investigate the tumorigenic transition in MASH-induced HCC, researchers predominantly exploit preclinical animal-based MASH models and studies based on archived human biopsies and clinical trials. Recapitulating the immune response during tumor development and progression is vital to obtain mechanistic insights into MASH-induced HCC. Notably, the advanced complexity behind MASLD and MASH pathogenesis shifted the research focus towards innate immunity, a fundamental element of the hepatic immune niche that is usually altered robustly in the course of liver disease. During the last few years, however, there has been an increasing interest for deciphering the role of adaptive immunity in MASH-induced HCC, particularly regarding the functions of the various T cell populations. To effectively understand the specific role of T cells in MASH-induced HCC development, scientists should urgently fill the current knowledge gaps in this field. Pinpointing the metabolic signature, sketching the immune landscape, and characterizing the cellular interactions and dynamics of the specific T cells within the MASH-HCC liver are essential to unravel the mechanisms that adaptive immunity exploits to enable the emergence and progression of this cancer. To this end, our review aims to summarize the current state of research regarding the T cell functions linked to MASH-induced HCC.

Macrophages Orchestrate the Liver Tumor Microenvironment

Liver cancer is one of the leading causes of cancer-related mortality. Hepatocellular carcinoma and cholangiocarcinoma are the most common types, and despite numerous advances, therapeutic options still remain poor for these cancer patients. Tumor development and progression strictly depend on a supportive tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immune cells population within a tumorigenic liver; they sustain cancer cells' growth and invasiveness, and their presence is correlated with a poor prognosis. Furthermore, TAM cross-talk with cells and components of the TME promotes immunosuppression, a desmoplastic response, and angiogenesis. In this review, we summarize the latest advances in understanding TAM heterogeneity and function, with a particular focus on TAM modulation of the TME. We also discuss the potential of targeting macrophage subpopulations and how this is now being exploited in current clinical trials for the treatment of liver cancer.

Cellular strategies to induce immune tolerance after liver transplantation: Clinical perspectives

Liver transplantation (LT) has become the most efficient treatment for pediatric and adult end-stage liver disease and the survival time after transplantation is becoming longer due to the development of surgical techniques and perioperative management. However, long-term side-effects of immunosuppressants, like infection, metabolic disorders and malignant tumor are gaining more attention. Immune tolerance is the status in which LT recipients no longer need to take any immunosuppressants, but the liver function and intrahepatic histology maintain normal. The approaches to achieve immune tolerance after transplantation include spontaneous, operational and induced tolerance. The first two means require no specific intervention but withdrawing immunosuppressant gradually during follow-up. No clinical factors or biomarkers so far could accurately predict who are suitable for immunosuppressant withdraw after transplantation. With the understanding to the underlying mechanisms of immune tolerance, many strategies have been developed to induce tolerance in LT recipients. Cellular strategy is one of the most promising methods for immune tolerance induction, including chimerism induced by hematopoietic stem cells and adoptive transfer of regulatory immune cells. The safety and efficacy of various cell products have been evaluated by prospective preclinical and clinical trials, while obstacles still exist before translating into clinical practice. Here, we will summarize the latest perspectives and concerns on the clinical application of cellular strategies in LT recipients.

The "Domino effect" in MASLD: The inflammatory cascade of steatohepatitis

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an increasingly common complication of obesity, affecting over a quarter of the global adult population. A key event in the pathophysiology of MASLD is the development of metabolic-associated steatohepatitis (MASH), which greatly increases the chances of developing cirrhosis and hepatocellular carcinoma. The underlying cause of MASH is multifactorial, but accumulating evidence indicates that the inflammatory process in the hepatic microenvironment typically follows a pattern that can be roughly divided into three stages: (1) Detection of hepatocyte stress by tissue-resident immune cells including γδ T cells and CD4-CD8- double-negative T cells, followed by their secretion of pro-inflammatory mediators, most notably IL-17A. (2) Recruitment of pro-inflammatory cells, mostly of the myeloid lineage, and initiation of inflammation through secretion of effector-type cytokines such as TNF, TGF-β, and IL-1β. (3) Escalation of the inflammatory response by recruitment of lymphocytes including Th17, CD8 T, and B cells leading to chronic inflammation, hepatic stellate cell activation, and fibrosis. Here we will discuss these three stages and how they are consecutively linked like falling domino tiles to the pathophysiology of MASH. Moreover, we will highlight the clinical potential of inflammation as a biomarker and therapeutic target for the treatment of MASLD.

The double roles of T cell-mediated immune response in the progression of MASLD

Metabolic dysfunction-associated steatotic liver disease(MASLD), formerly known as non-alcoholic fatty liver disease(NAFLD), has become a major cause of chronic liver disease and a significant risk factor for hepatocellular carcinoma, which poses a huge burden on global public health and economy. MASLD includes steatotic liver disease, steatohepatitis, and cirrhosis, and the latter two cause great harm to human health and life, even complicated with liver cancer. Immunologic mechanism plays a major role in promoting its development into hepatitis and cirrhosis. Now more and more evidences show that T cells play an important role in the progression of MASLD. In this review, we discuss the double roles of T cells in MASLD from the perspective of T cell response pathways, as well as new evidences regarding the possible application of immunomodulatory therapy in MASH.

Immune tolerance promotion by LSEC-specific lentiviral vector-mediated expression of the transgene regulated by the stabilin-2 promoter

Liver sinusoidal endothelial cells (LSECs) are specialized endocytic cells that clear the body from blood-borne pathogens and waste macromolecules through scavenger receptors (SRs). Among the various SRs expressed by LSECs is stabilin-2 (STAB2), a class H SR that binds to several ligands, among which endogenous coagulation products. Given the well-established tolerogenic function of LSECs, we asked whether the STAB2 promoter (STAB2p) would enable us to achieve LSEC-specific lentiviral vector (LV)-mediated transgene expression, and whether the expression of this transgene would be maintained over the long term due to tolerance induction. Here, we show that STAB2p ensures LSEC-specific green fluorescent protein (GFP) expression by LV in the absence of a specific cytotoxic CD8+ T cell immune response, even in the presence of GFP-specific CD8+ T cells, confirming the robust tolerogenic function of LSECs. Finally, we show that our delivery system can partially and permanently restore FVIII activity in a mouse model of severe hemophilia A without the formation of anti-FVIII antibodies. Overall, our findings establish the suitability of STAB2p for long-term LSEC-restricted expression of therapeutic proteins, such as FVIII, or to achieve antigen-specific immune tolerance in auto-immune diseases.

Tolerogenic Nano-/Microparticle Vaccines for Immunotherapy

Autoimmune diseases, allergies, transplant rejections, generation of antidrug antibodies, and chronic inflammatory diseases have impacted a large group of people across the globe. Conventional treatments and therapies often use systemic or broad immunosuppression with serious efficacy and safety issues. Tolerogenic vaccines represent a concept that has been extended from their traditional immune-modulating function to induction of antigen-specific tolerance through the generation of regulatory T cells. Without impairing immune homeostasis, tolerogenic vaccines dampen inflammation and induce tolerogenic regulation. However, achieving the desired potency of tolerogenic vaccines as preventive and therapeutic modalities calls for precise manipulation of the immune microenvironment and control over the tolerogenic responses against the autoantigens, allergens, and/or alloantigens. Engineered nano-/microparticles possess desirable design features that can bolster targeted immune regulation and enhance the induction of antigen-specific tolerance. Thus, particle-based tolerogenic vaccines hold great promise in clinical translation for future treatment of aforementioned immune disorders. In this review, we highlight the main strategies to employ particles as exciting tolerogenic vaccines, with a focus on the particles' role in facilitating the induction of antigen-specific tolerance. We describe the particle design features that facilitate their usage and discuss the challenges and opportunities for designing next-generation particle-based tolerogenic vaccines with robust efficacy to promote antigen-specific tolerance for immunotherapy.

Progress of immune checkpoint inhibitors therapy for non-small cell lung cancer with liver metastases

Nearly one-fifth of patients with non-small cell Lung Cancer (NSCLC) will develop liver metastases (LMs), and the overall treatment strategy of LMs will directly affect the survival of patients. However, some retrospective studies have found that patients receiving chemotherapy or targeted therapy have a poorer prognosis once LMs develop. In recent years, multiple randomised controlled trials (RCTS) have shown significant improvements in outcomes for patients with advanced lung cancer following the introduction of immune checkpoint inhibitors (ICIs) compared to conventional chemotherapy. ICIs is safe and effective in patients with LMs, although patients with LMs are mostly underrepresented in randomised clinical trials. However, NSCLC patients with LMs have a significantly worse prognosis than those without LMs when treated with ICIs, and the mechanism by which LMs induce systemic anti-tumour immunity reduction is unknown, so the management of LMs in patients with NSCLC is a clinical challenge that requires more optimised therapies to achieve effective disease control. In this review, we summarised the mechanism of ICIs in the treatment of LMs, the clinical research and treatment progress of ICIs and their combination with other therapies in patients with LMs from NSCLC.

Lung single-cell RNA profiling reveals response of pulmonary capillary to sepsis-induced acute lung injury

Background

Sepsis-induced acute lung injury (ALI) poses a significant threat to human health. Endothelial cells, especially pulmonary capillaries, are the primary barriers against sepsis in the lungs. Therefore, investigating endothelial cell function is essential to understand the pathophysiological processes of sepsis-induced ALI.

Methods

We downloaded single-cell RNA-seq expression data from GEO with accession number GSE207651. The mice underwent cecal ligation and puncture (CLP) surgery, and lung tissue samples were collected at 0, 24, and 48 h. The cells were annotated using the CellMarker database and FindAllMarkers functions. GO enrichment analyses were performed using the Metascape software. Gene set enrichment Analysis (GSEA) and variation Analysis (GSVA) were performed to identify differential signaling pathways. Differential expression genes were collected with the "FindMarkers" function. The R package AUCell was used to score individual cells for pathway activities. The Cellchat package was used to explore intracellular communication.

Results

Granulocytes increased significantly as the duration of endotoxemia increased. However, the number of T cells, NK cells, and B cells declined. Pulmonary capillary cells were grouped into three sub-clusters. Capillary-3 cells were enriched in the sham group, but declined sharply in the CLP.24 group. Capillary-1 cells peaked in the CLP.24 group, while Capillary-2 cells were enriched in the CLP.48 group. Furthermore, we found that Cd74+ Capillary-3 cells mainly participated in immune interactions. Plat+ Capillary-1 and Clec1a+ Capillary-2 are involved in various physiological processes. Regarding cell-cell interactions, Plat+ Capillary-1 plays the most critical role in granulocyte adherence to capillaries during ALI. Cd74+ Capillary cells expressing high levels of major histocompatibility complex (MHC) and mainly interacted with Cd8a+ T cells in the sham group.

Conclusion

Plat+ capillaries are involved in the innate immune response through their interaction with neutrophils via ICAM-1 adhesion during endotoxemia, while Cd74+ capillaries epxressed high level of MHC proteins play a role in adaptive immune response through their interaction with T cells. However, it remains unclear whether the function of Cd74+ capillaries leans towards immunity or tolerance, and further studies are needed to confirm this.

Lipid metabolism in the immune niche of tumor-prone liver microenvironment

The liver is a common primary site not only for tumorigenesis, but also for cancer metastasis. Advanced cancer patients with liver metastases also show reduced response rates and survival benefits when treated with immune checkpoint inhibitors. Accumulating evidence has highlighted the importance of the liver immune microenvironment in determining tumorigenesis, metastasis-organotropism, and immunotherapy resistance. Various immune cells such as T cells, natural killer and natural killer T cells, macrophages and dendritic cells, and stromal cells including liver sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, and hepatocytes are implicated in contributing to the immune niche of tumor-prone liver microenvironment. In parallel, as the major organ for lipid metabolism, the increased abundance of lipids and their metabolites is linked to processes crucial for nonalcoholic fatty liver disease and related liver cancer development. Furthermore, the proliferation, differentiation, and functions of hepatic immune and stromal cells are also reported to be regulated by lipid metabolism. Therefore, targeting lipid metabolism may hold great potential to reprogram the immunosuppressive liver microenvironment and synergistically enhance the immunotherapy efficacy in the circumstance of liver metastasis. In this review, we describe how the hepatic microenvironment adapts to the lipid metabolic alterations in pathologic conditions like nonalcoholic fatty liver disease. We also illustrate how these immunometabolic alterations promote the development of liver cancers and immunotherapy resistance. Finally, we discuss the current therapeutic options and hypothetic combination immunotherapies for the treatment of advanced liver cancers.

Liver-Targeting Nanoplatforms for the Induction of Immune Tolerance

Liver-targeting nanoparticles have emerged as a promising platform for the induction of immune tolerance by taking advantage of the liver's unique tolerogenic properties and nanoparticles' physicochemical flexibility. Such an approach provides a versatile solution to the treatment of a diversity of immunologic diseases. In this review, we begin by assessing the design parameters integral to cell-specific targeting and the tolerogenic induction of nanoplatforms engineered to target the four critical immunogenic hepatic cells, including liver sinusoidal epithelial cells (LSECs), Kupffer cells (KCs), hepatic stellate cells (HSCs), and hepatocytes. We also include an overview of multiple therapeutic strategies in which nanoparticles are being studied to treat many allergies and autoimmune disorders. Finally, we explore the challenges of using nanoparticles in this field while highlighting future avenues to expand the therapeutic utility of liver-targeting nanoparticles in autoimmune processes.

Interorgan communication with the liver: novel mechanisms and therapeutic targets

The liver is a multifunctional organ that plays crucial roles in numerous physiological processes, such as production of bile and proteins for blood plasma, regulation of blood levels of amino acids, processing of hemoglobin, clearance of metabolic waste, maintenance of glucose, etc. Therefore, the liver is essential for the homeostasis of organisms. With the development of research on the liver, there is growing concern about its effect on immune cells of innate and adaptive immunity. For example, the liver regulates the proliferation, differentiation, and effector functions of immune cells through various secreted proteins (also known as "hepatokines"). As a result, the liver is identified as an important regulator of the immune system. Furthermore, many diseases resulting from immune disorders are thought to be related to the dysfunction of the liver, including systemic lupus erythematosus, multiple sclerosis, and heart failure. Thus, the liver plays a role in remote immune regulation and is intricately linked with systemic immunity. This review provides a comprehensive overview of the liver remote regulation of the body's innate and adaptive immunity regarding to main areas: immune-related molecules secreted by the liver and the liver-resident cells. Additionally, we assessed the influence of the liver on various facets of systemic immune-related diseases, offering insights into the clinical application of target therapies for liver immune regulation, as well as future developmental trends.

Role of the immune system in liver transplantation and its implications for therapeutic interventions

Liver transplantation (LT) stands as the gold standard for treating end-stage liver disease and hepatocellular carcinoma, yet postoperative complications continue to impact survival rates. The liver's unique immune system, governed by a microenvironment of diverse immune cells, is disrupted during processes like ischemia-reperfusion injury posttransplantation, leading to immune imbalance, inflammation, and subsequent complications. In the posttransplantation period, immune cells within the liver collaboratively foster a tolerant environment, crucial for immune tolerance and liver regeneration. While clinical trials exploring cell therapy for LT complications exist, a comprehensive summary is lacking. This review provides an insight into the intricacies of the liver's immune microenvironment, with a specific focus on macrophages and T cells as primary immune players. Delving into the immunological dynamics at different stages of LT, we explore the disruptions after LT and subsequent immune responses. Focusing on immune cell targeting for treating liver transplant complications, we provide a comprehensive summary of ongoing clinical trials in this domain, especially cell therapies. Furthermore, we offer innovative treatment strategies that leverage the opportunities and prospects identified in the therapeutic landscape. This review seeks to advance our understanding of LT immunology and steer the development of precise therapies for postoperative complications.

Deciphering the tumour immune microenvironment of hepatocellular carcinoma

Current treatments for hepatocellular carcinoma (HCC) are less effective and prone to recurrence after surgery, so it's needed to seek new ideas for its therapy. Tumour immune microenvironment (TME) is crucial for the pathogenesis, development and metastasis of HCC. Interactions between immune cells and tumour cells significantly impact responses to immunotherapies and patient prognosis. In recent years, immunotherapies for HCC have shown promising potential, but the response rate is still unsatisfactory. Understanding their cross-talks is helpful for selecting potential therapeutic targets, predicting immunotherapy responses, determining immunotherapy efficacy, identifying prognostic markers and selecting individualized treatment options. In this paper, we reviewed the research advances on the roles of immune cells and multi-omic research associated with HCC pathogenesis and therapy, and future perspectives on TME.

Unveiling the Role of Tumor-Infiltrating T Cells and Immunotherapy in Hepatocellular Carcinoma: A Comprehensive Review

Hepatocellular carcinoma (HCC) is a rapidly rising global health concern, ranking as the third-leading cause of cancer-related mortality. Despite medical advancements, the five-year survival rate remains a dismal 18%, with a daunting 70% recurrence rate within a five-year period. Current systematic treatments, including first-line sorafenib, yield an overall response rate (ORR) below 10%. In contrast, immunotherapies have shown promise by improving ORR to approximately 30%. The IMbravel150 clinical trial demonstrates that combining atezolizumab and bevacizumab surpasses sorafenib in terms of median progression-free survival (PFS) and overall survival (OS). However, the therapeutic efficacy for HCC patients remains unsatisfactory, highlighting the urgent need for a comprehensive understanding of antitumor responses and immune evasion mechanisms in HCC. In this context, understanding the immune landscape of HCC is of paramount importance. Tumor-infiltrating T cells, including cytotoxic T cells, regulatory T cells, and natural killer T cells, are key components in the antitumor immune response. This review aims to shed light on their intricate interactions within the immunosuppressive tumor microenvironment and explores potential strategies for revitalizing dysfunctional T cells. Additionally, current immune checkpoint inhibitor (ICI)-based trials, ICI-based combination therapies, and CAR-T- or TCR-T-cell therapies for HCC are summarized, which might further improve OS and transform the management of HCC in the future.

IFNγ and CTLA-4 Drive Hepatic CD4 T-Cell Tolerance and Protection From Autoimmunity in Mice

BACKGROUND & AIMS

The liver has a distinct capacity to induce immune tolerance to hepatic antigens. Although liver tolerance can be advantageous for preventing autoimmune and inflammatory diseases, it also can be detrimental by preventing immune surveillance of infected or malignant cells. Here, we investigated the immune mechanisms that establish hepatic tolerance.

METHODS

Tolerance was investigated in C-reactive protein (CRP)-myelin basic protein (MBP) mice expressing the neuroantigen MBP in hepatocytes, providing profound resistance to MBP-induced neuroinflammation. Tolerance induction was studied after transfer of MBP-specific CD4 T cells into CRP-MBP mice, and tolerance mechanisms were tested using depleting or blocking antibodies.

RESULTS

Although tolerant CRP-MBP mice display increased numbers of forkhead box P3+ regulatory T cells, we here found them not essential for the maintenance of hepatic tolerance. Instead, upon MBP recognition in the liver, MBP-specific T cells became activated to produce interferon (IFN)γ, which, in turn, induced local up-regulation of recruitment molecules, including Chemokine (C-X-C motif) ligand9 and its receptor C-X-C motif chemokine receptor3, facilitating endothelial translocation and redirection of MBP-specific T cells into the hepatic parenchyma. There, the translocated MBP-specific CD4 T cells partly converted into interleukin 10-producing type 1 regulatory T cells, and significantly up-regulated the expression of immune checkpoint molecules, notably cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Intriguingly, although liver tolerance was not affected by impairment of interleukin 10 signaling, concomitant blockade of IFNγ and CTLA-4 abrogated hepatic tolerance induction to MBP, resulting in neuroinflammatory autoimmune disease in these mice.

CONCLUSIONS

IFNγ-mediated redirection of autoreactive CD4 T cells into the liver and up-regulation of checkpoint molecules, including CTLA-4, were essential for tolerance induction in the liver, hence representing a potential treatment target for boosting or preventing liver tolerance.

Liver metastasis affects progression pattern during immune checkpoint inhibitors monotherapy in gastric cancer

Introduction

The efficacy of immune checkpoint inhibitors (ICIs) is heterogeneous at each metastatic site, and tumor progression pattern is associated with survival; however, it remains unclear in gastric cancer (GC). Therefore, we aimed to clarify the progression pattern in response to ICIs in patients with GC, and we analyzed its mechanism focusing on the intratumoral immune cells.

Methods

Patients who received ICIs were retrospectively classified into non-systemic and systemic progression groups based on their radiological assessments. Moreover, the best percentage change in target lesions from each organ was compared.

Results

Among 148 patients, the non-systemic progression group showed a significant improvement in overall survival (OS) compared with the systemic progression group (median, 5.6 months vs. 3.3 months; HR, 0.53; 95%CI, 0.32-0.89; p = 0.012). Poor performance status (HR, 1.73, 95%CI, 1.00-2.87) and systemic progression (HR, 3.09, 95%CI, 1.95-4.82) were associated with OS. Of all metastatic sites, the liver showed the poorest percentage change, and liver metastasis (OR, 2.99, 95%CI, 1.04-8.58) was associated with systemic progression. Hence, intratumoral CD8+ T-cell density was lower in patients with liver metastasis than in those without liver metastasis after ICIs, although the density of CD4+ T-cells (Th1, Th17, and Treg) and CD163+ cells (TAM) were not significantly different.

Conclusion

The new progression pattern was associated with OS in GC. Liver metastasis may be a predictive factor of systemic progression during ICIs by regulating intratumoral CD8+ T-cells.

Development and Validation of a Prognostic Risk Model for Patients with Advanced Melanoma Treated with Immune Checkpoint Inhibitors

BACKGROUND

Risk stratification tools for patients with advanced melanoma (AM) treated with immune checkpoint inhibitors (ICI) are lacking. We identified a new prognostic model associated with overall survival (OS).

PATIENTS AND METHODS

A total of 318 treatment naïve patients with AM receiving ICI were collected from a multi-centre retrospective cohort study. LASSO Cox regression identified independent prognostic factors associated with OS. Model validation was carried out on 500 iterations of bootstrapped samples. Harrel's C-index was calculated and internally validated to outline the model's discriminatory performance. External validation was carried out in 142 advanced melanoma patients receiving ICI in later lines.

RESULTS

High white blood cell count (WBC), high lactate dehydrogenase (LDH), low albumin, Eastern Cooperative Oncology Group (ECOG) performance status ≥1, and the presence of liver metastases were included in the model. Patients were parsed into 3 risk groups: favorable (0-1 factors) OS of 52.9 months, intermediate (2-3 factors) OS 13.0 months, and poor (≥4 factors) OS 2.7 months. The C-index of the model from the discovery cohort was 0.69. External validation in later-lines (N = 142) of therapy demonstrated a c-index of 0.65.

CONCLUSIONS

Liver metastases, low albumin, high LDH, high WBC, and ECOG≥1 can be combined into a prognostic model for AM patients treated with ICI.

Immune response to foreign materials in spinal fusion surgery

Spinal fusion surgery is a common procedure used to stabilize the spine and treat back pain. The procedure involves the use of foreign materials such as screws, rods, or cages, which can trigger a foreign body reaction, an immune response that involves the activation of immune cells such as macrophages and lymphocytes. The foreign body reaction can impact the success of spinal fusion, as it can interfere with bone growth and fusion. This review article provides an overview of the cellular and molecular events in the foreign body reaction, the impact of the immune response on spinal fusion, and strategies to minimize its impact. By carefully considering the use of foreign materials and optimizing surgical techniques, the impact of the foreign body reaction can be reduced, leading to better outcomes for patients.

The evolving role of liver sinusoidal endothelial cells in liver health and disease

LSECs are a unique population of endothelial cells within the liver and are recognized as key regulators of liver homeostasis. LSECs also play a key role in liver disease, as dysregulation of their quiescent phenotype promotes pathological processes within the liver including inflammation, microvascular thrombosis, fibrosis, and portal hypertension. Recent technical advances in single-cell analysis have characterized distinct subpopulations of the LSECs themselves with a high resolution and defined their gene expression profile and phenotype, broadening our understanding of their mechanistic role in liver biology. This article will review 4 broad advances in our understanding of LSEC biology in general: (1) LSEC heterogeneity, (2) LSEC aging and senescence, (3) LSEC role in liver regeneration, and (4) LSEC role in liver inflammation and will then review the role of LSECs in various liver pathologies including fibrosis, DILI, alcohol-associated liver disease, NASH, viral hepatitis, liver transplant rejection, and ischemia reperfusion injury. The review will conclude with a discussion of gaps in knowledge and areas for future research.

Insights gained from single-cell RNA analysis of murine endothelial cells in aging hearts

Aging is the strongest risk factor for cardiovascular disease, with progressive decline in the function of vascular endothelial cells (ECs) with age. Systematic analyses of the effects of aging on different cardiac EC types remain limited. Here, we constructed a scRNA atlas of EC transcriptomes in young and old mouse hearts. We identified 10 EC subclusters. The multidimensionally differential genes (DEGs) analysis across different EC clusters shows molecular changes with aging, showing the increase in the overall inflammatory microenvironment and the decrease in angiogenesis and cytoskeletal support capacity of aged ECs. And we performed an in-depth analysis of 3 special ECs, Immunology, Proliferating and Angiogenic. The Immunology EC seems highly associated with some immune regulatory functions, which decline with aging at different degrees. Analysis of two types of neovascular ECs, Proliferating, Angiogenic, implied that Angiogenic ECs can differentiate into multiple EC directions after initially originating from proliferating ECs. And aging leads to a decrease in the ability of vascular angiogenesis and differentiation. Finally, we summarized the effects of aging on cell signaling communication between different EC clusters. This cardiac EC atlas offers comprehensive insights into the molecular regulations of cardiovascular aging, and provides new directions for the prevention and treatment of age-related cardiovascular disease.

Gut Microbiota and the Microvasculature

The gut microbiota is increasingly recognized as an actuating variable shaping vascular development and endothelial cell function in the intestinal mucosa but also affecting the microvasculature of remote organs. In the small intestine, colonization with gut microbiota and subsequent activation of innate immune pathways promotes the development of intricate capillary networks and lacteals, influencing the integrity of the gut-vascular barrier as well as nutrient uptake. Since the liver yields most of its blood supply via the portal circulation, the hepatic microcirculation steadily encounters microbiota-derived patterns and active signaling metabolites that induce changes in the organization of the liver sinusoidal endothelium, influencing immune zonation of sinusoids and impacting on metabolic processes. In addition, microbiota-derived signals may affect the vasculature of distant organ systems such as the brain and the eye microvasculature. In recent years, this gut-resident microbial ecosystem was revealed to contribute to the development of several vascular disease phenotypes.

Transcriptome wide functional analysis of HBx expressing human hepatocytes stimulated with endothelial cell cross-talk

Identification of genes dysregulated during the hepatitis B virus (HBV)-host cell interaction adds to the understanding of underlying molecular mechanisms and aids in discovering effective therapies to improve prognosis in hepatitis B virus (HBV)-infected individuals. Through bioinformatics analyses of transcriptomics data, this study aimed to identify potential genes involved in the cross-talk of human hepatocytes expressing the HBV viral protein HBx with endothelial cells. Transient transfection of HBV viral gene X (HBx) was performed in THLE2 cells using pcDNA3 constructs. Through mRNA Sequencing (RNA Seq) analysis, differentially expressed genes (DEGs) were identified. THLE2 cells transfected with HBx (THLE2x) were further treated with conditioned medium from cultured human umbilical vein derived endothelial cells (HUVEC-CM). Gene Ontology (GO) enrichment analysis revealed that interferon and cytokine signaling pathways were primarily enriched for the downregulated DEGs in THLE2x cells treated with HUVEC-CM. One significant module was selected following protein-protein interaction (PPI) network generation, and thirteen hub genes were identified from the module. The prognostic values of the hub genes were evaluated using Kaplan-Meier (KM) plotter, and three genes (IRF7, IFIT1, and IFITM1) correlated with poor disease specific survival (DSS) in HCC patients with chronic hepatitis. A comparison of the DEGs identified in HUVEC-stimulated THLE2x cells with four publicly available HBV-related HCC microarray datasets revealed that PLAC8 was consistently downregulated in all four HCC datasets as well as in HUVEC-CM treated THLE2x cells. KM plots revealed that PLAC8 correlated with worse relapse free survival and progression free survival in HCC patients with hepatitis B virus infection. This study provided molecular insights which may help develop a deeper understanding of HBV-host stromal cell interaction and open avenues for future research.

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.

Maternal hepatic immunology during pregnancy

The liver plays pivotal roles in immunologic responses, and correct hepatic adaptations in maternal immunology are required during pregnancy. In this review, we focus on anatomical and immunological maternal hepatic adaptations during pregnancy, including our recent reports in this area. Moreover, we summarize maternal pregnancy-associated liver diseases, including hyperemesis gravidarum; intrahepatic cholestasis of pregnancy; preeclampsia, specifically hemolysis, elevated liver enzymes, and low platelet count syndrome; and acute fatty liver of pregnancy. In addition, the latest information about the factors that regulate hepatic immunology during pregnancy are reviewed for the first time, including human chorionic gonadotropin, estrogen, progesterone, growth hormone, insulin like growth factor 1, oxytocin, adrenocorticotropic hormone, adrenal hormone, prolactin, melatonin and prostaglandins. In summary, the latest progress on maternal hepatic anatomy and immunological adaptations, maternal pregnancy-associated diseases and the factors that regulate hepatic immunology during pregnancy are discussed, which may be used to prevent embryo loss and abortion, as well as pregnancy-associated liver diseases.

Microvascular Thrombosis and Liver Fibrosis Progression: Mechanisms and Clinical Applications

Fibrosis is an unavoidable consequence of chronic inflammation. Extracellular matrix deposition by fibroblasts, stimulated by multiple pathways, is the first step in the onset of chronic liver disease, and its propagation promotes liver dysfunction. At the same time, chronic liver disease is characterized by alterations in primary and secondary hemostasis but unlike previously thought, these changes are not associated with an increased risk of bleeding complications. In recent years, the role of coagulation imbalance has been postulated as one of the main mechanisms promoting hepatic fibrogenesis. In this review, we aim to investigate the function of microvascular thrombosis in the progression of liver disease and highlight the molecular and cellular networks linking hemostasis to fibrosis in this context. We analyze the predictive and prognostic role of coagulation products as biomarkers of liver decompensation (ascites, variceal hemorrhage, and hepatic encephalopathy) and liver-related mortality. Finally, we evaluate the current evidence on the application of antiplatelet and anticoagulant therapies for prophylaxis of hepatic decompensation or prevention of the progression of liver fibrosis.

Promises and challenges of mucosal COVID-19 vaccines

Coronavirus disease-2019 (COVID-19) is an ongoing pandemic caused by the newly emerged virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, COVID-19 vaccines are given intramuscularly and they have been shown to evoke systemic immune responses that are highly efficacious towards preventing severe disease and death. However, vaccine-induced immunity wanes within a short time, and booster doses are currently recommended. Furthermore, current vaccine formulations do not adequately restrict virus infection at the mucosal sites, such as in the nasopharyngeal tract and, therefore, have limited capacity to block virus transmission. With these challenges in mind, several mucosal vaccines are currently being developed with the aim of inducing long-lasting protective immune responses at the mucosal sites where SARS-COV-2 infection begins. Past successes in mucosal vaccinations underscore the potential of these developmental stage SARS-CoV-2 vaccines to reduce disease burden, if not eliminate it altogether. Here, we discuss immune responses that are triggered at the mucosal sites and recent advances in our understanding of mucosal responses induced by SARS-CoV-2 infection and current COVID-19 vaccines. We also highlight several mucosal SARS-COV-2 vaccine formulations that are currently being developed or tested for human use and discuss potential challenges to mucosal vaccination.

Cross-presentation by the others

The critical role of conventional dendritic cells in physiological cross-priming of immune responses to tumors and pathogens is widely documented and beyond doubt. However, there is ample evidence that a wide range of other cell types can also acquire the capacity to cross-present. These include not only other myeloid cells such as plasmacytoid dendritic cells, macrophages and neutrophils, but also lymphoid populations, endothelial and epithelial cells and stromal cells including fibroblasts. The aim of this review is to provide an overview of the relevant literature that analyzes each report cited for the antigens and readouts used, mechanistic insight and in vivo experimentation addressing physiological relevance. As this analysis shows, many reports rely on the exceptionally sensitive recognition of an ovalbumin peptide by a transgenic T cell receptor, with results that therefore cannot always be extrapolated to physiological settings. Mechanistic studies remain basic in most cases but reveal that the cytosolic pathway is dominant across many cell types, while vacuolar processing is most encountered in macrophages. Studies addressing physiological relevance rigorously remain exceptional but suggest that cross-presentation by non-dendritic cells may have significant impact in anti-tumor immunity and autoimmunity.

Remodeling the hepatic fibrotic microenvironment with emerging nanotherapeutics: a comprehensive review

Liver fibrosis could be the last hope for treating liver cancer and remodeling of the hepatic microenvironment has emerged as a strategy to promote the ablation of liver fibrosis. In recent years, especially with the rapid development of nanomedicine, hepatic microenvironment therapy has been widely researched in studies concerning liver cancer and fibrosis. In this comprehensive review, we summarized recent advances in nano therapy-based remodeling of the hepatic microenvironment. Firstly, we discussed novel strategies for regulatory immune suppression caused by capillarization of liver sinusoidal endothelial cells (LSECs) and macrophage polarization. Furthermore, metabolic reprogramming and extracellular matrix (ECM) deposition are caused by the activation of hepatic stellate cells (HSCs). In addition, recent advances in ROS, hypoxia, and impaired vascular remodeling in the hepatic fibrotic microenvironment due to ECM deposition have also been summarized. Finally, emerging nanotherapeutic approaches based on correlated signals were discussed in this review. We have proposed novel strategies such as engineered nanotherapeutics targeting antigen-presenting cells (APCs) or direct targeting T cells in liver fibrotic immunotherapy to be used in preventing liver fibrosis. In summary, this comprehensive review illustrated the opportunities in drug targeting and nanomedicine, and the current challenges to be addressed.

A key driver to promote HCC: Cellular crosstalk in tumor microenvironment

Liver cancer is the third greatest cause of cancer-related mortality, which of the major pathological type is hepatocellular carcinoma (HCC) accounting for more than 90%. HCC is characterized by high mortality and is predisposed to metastasis and relapse, leading to a low five-year survival rate and poor clinical prognosis. Numerous crosstalk among tumor parenchymal cells, anti-tumor cells, stroma cells, and immunosuppressive cells contributes to the immunosuppressive tumor microenvironment (TME), in which the function and frequency of anti-tumor cells are reduced with that of associated pro-tumor cells increasing, accordingly resulting in tumor malignant progression. Indeed, sorting out and understanding the signaling pathways and molecular mechanisms of cellular crosstalk in TME is crucial to discover more key targets and specific biomarkers, so that develop more efficient methods for early diagnosis and individualized treatment of liver cancer. This piece of writing offers insight into the recent advances in HCC-TME and reviews various mechanisms that promote HCC malignant progression from the perspective of mutual crosstalk among different types of cells in TME, aiming to assist in identifying the possible research directions and methods in the future for discovering new targets that could prevent HCC malignant progression.

Role of immune responses for development of NAFLD-associated liver cancer and prospects for therapeutic modulation

The liver is the central metabolic organ of the body regulating energy and lipid metabolism and at the same time has potent immunological functions. Overwhelming the metabolic capacity of the liver by obesity and sedentary lifestyle leads to hepatic lipid accumulation, chronic necro-inflammation, enhanced mitochondrial/ER-stress and development of non-alcoholic fatty liver disease (NAFLD), with its pathologic form nonalcoholic steatohepatitis (NASH). Based on knowledge on pathophysiological mechanisms, specifically targeting metabolic diseases to prevent or slow down progression of NAFLD to liver cancer will become possible. Genetic/environmental factors contribute to development of NASH and liver cancer progression. The complex pathophysiology of NAFLD-NASH is reflected by environmental factors, particularly the gut microbiome and its metabolic products. NAFLD-associated HCC occurs in most of the cases in the context of a chronically inflamed liver and cirrhosis. Recognition of environmental alarmins or metabolites derived from the gut microbiota and the metabolically injured liver create a strong inflammatory milieu supported by innate and adaptive immunity. Several recent studies indicate that the chronic hepatic microenvironment of steatosis induces auto-aggressive CD8+CXCR6+PD1+ T cells secreting TNF and upregulating FasL to eliminate parenchymal and non-parenchymal cells in an antigen independent manner. This promotes chronic liver damage and a pro-tumorigenic environment. CD8+CXCR6+PD1+ T cells possess an exhausted, hyperactivated, resident phenotype and trigger NASH to HCC transition, and might be responsible for a less efficient treatment response to immune-check-point inhibitors - in particular atezolizumab/bevacizumab. Here, we provide an overview of NASH-related inflammation/pathogenesis focusing on new discoveries on the role of T cells in NASH-immunopathology and therapy response. This review discusses preventive measures to halt disease progression to liver cancer and therapeutic strategies to manage NASH-HCC patients.

Immunotherapy and tumor mutational burden in cancer patients with liver metastases: A meta and real word cohort analysis

Background

The predictive effects of liver metastases for immune-checkpoint inhibitors (ICIs) and the relationship between tumor mutational burden (TMB) and liver metastases (LM) remain unclear.

Methods

A systematic review and meta-analysis were conducted to explore the heterogeneity of ICIs efficacy between patients with or without LM. A pan-cancer cohort of 1,661 patients who received ICIs was downloaded and analyzed to assess the association between TMB and LM.

Results

Of 21053 studies identified in our search, eight single-arm studies and 24 randomized controlled trials were included. Overall, 17957 patients with advanced or metastatic cancers (4805 patients (26.8%) with LM and 13151 patients (73.2%) without LM) were enrolled. The pooled objective response rate (ORR) was 8.5% (95% CI 4%-13%) in the LM group versus 21% (95% CI 16%-21%) in the non-LM group. The pooled hazard ratio (HR) for death was 0.85 (95% CI 0.80-0.90) in the LM group treated with ICIs compared with the standard of care. In patients without LM who were treated with ICIs, the pooled HR for death was 0.78 (95% CI 0.73-0.82) compared with the standard of care. The difference in efficacy between patients with or without LM treated with ICIs was significant (p=0.04). Pan-cancer analysis revealed that the TMB-high rate was 10.8% in liver metastatic lesions versus 21.4% in other metastatic lesions (p=0.004). In addition, TMB was also significantly associated with OS as a binary cutoff (p=0.05) and was an independent prognostic variable (HR=0.98, P=0.047) as a continuous variable in patients with LM.

Conclusions

In patients with LM, the efficacy of immunotherapy was attenuated, but TMB-high could predict better survival outcomes.

Baseline Radiomic Signature to Estimate Overall Survival in Patients With NSCLC

INTRODUCTION

We aimed to define a baseline radiomic signature associated with overall survival (OS) using baseline computed tomography (CT) images obtained from patients with NSCLC treated with nivolumab or chemotherapy.

METHODS

The radiomic signature was developed in patients with NSCLC treated with nivolumab in CheckMate-017, -026, and -063. Nivolumab-treated patients were pooled and randomized to training, calibration, or validation sets using a 2:1:1 ratio. From baseline CT images, volume of tumor lesions was semiautomatically segmented, and 38 radiomic variables depicting tumor phenotype were extracted. Association between the radiomic signature and OS was assessed in the nivolumab-treated (validation set) and chemotherapy-treated (test set) patients in these studies.

RESULTS

A baseline radiomic signature was identified using CT images obtained from 758 patients. The radiomic signature used a combination of imaging variables (spatial correlation, tumor volume in the liver, and tumor volume in the mediastinal lymph nodes) to output a continuous value, ranging from 0 to 1 (from most to least favorable estimated OS). Given a threshold of 0.55, the sensitivity and specificity of the radiomic signature for predicting 3-month OS were 86% and 77.8%, respectively. The signature was identified in the training set of patients treated with nivolumab and was significantly associated (p < 0.0001) with OS in patients treated with nivolumab or chemotherapy.

CONCLUSIONS

The radiomic signature provides an early readout of the anticipated OS in patients with NSCLC treated with nivolumab or chemotherapy. This could provide important prognostic information and may support risk stratification in clinical trials.

Immunotolerance in liver transplantation: a primer for the clinician

The use of immunosuppressive medications for solid organ transplantation is associated with cardiovascular, metabolic, and oncologic complications. On the other hand, the development of graft rejection is associated with increased mortality and graft dysfunction. Liver transplant recipients can withdraw from immunosuppression without developing graft injury while preserving an adequate antimicrobial response - a characteristic known as immunotolerance. Immunotolerance can be spontaneously or pharmacologically achieved. Contrary to the classic dogma, clinical studies have elucidated low rates of true spontaneous immunotolerance (no serologic or histological markers of immune injury) among liver transplant recipients. However, clinical, serologic, and tissue biomarkers can aid in selecting patients in whom immunosuppression can be safely withdrawn. For those who failed an immunosuppression withdrawal trial or are at high risk of rejection, pharmacological interventions for immunotolerance induction are under development. In this review, we provide an overview of the mechanisms of immunotolerance, the clinical studies investigating predictors and biomarkers of spontaneous immunotolerance, as well as the potential pharmacological interventions for inducing it.

The Tumor Microenvironment of Hepatocellular Carcinoma: Untying an Intricate Immunological Network

HCC, the most prevalent form of primary liver cancer, is prototypically an inflammation-driven cancer developing after years of inflammatory insults. Consequently, the hepatic microenvironment is a site of complex immunological activities. Moreover, the tolerogenic nature of the liver can act as a barrier to anti-tumor immunity, fostering cancer progression and resistance to immunotherapies based on immune checkpoint inhibitors (ICB). In addition to being a site of primary carcinogenesis, many cancer types have high tropism for the liver, and patients diagnosed with liver metastasis have a dismal prognosis. Therefore, understanding the immunological networks characterizing the tumor microenvironment (TME) of HCC will deepen our understanding of liver immunity, and it will underpin the dominant mechanisms controlling both spontaneous and therapy-induced anti-tumor immune responses. Herein, we discuss the contributions of the cellular and molecular components of the liver immune contexture during HCC onset and progression by underscoring how the balance between antagonistic immune responses can recast the properties of the TME and the response to ICB.

Splenectomy induces biochemical remission and regeneration in experimental murine autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic immune-mediated inflammatory liver disease. It is known that AIH originates not from the spleen but from the liver itself. Nonetheless, most details of the etiology and pathophysiology are unknown. We induced experimental murine AIH (emAIH) in NOD/Ltj mice by single administration of a replication-deficient adenovirus and performed splenectomy during late-stage disease. Biochemical disease remission occurred, which was characterized by improvement in transaminase levels. The causes of this remission included a shift in the transcriptomic signature of serum proteins toward regeneration. At the cellular level, there was a marked decrease in activated CD8⁺ T cells and an increase in intrahepatic regulatory T cells (Tregs). Here, intrahepatic Treg numbers correlated with biochemical remission. Notably, an imbalance in the T-cell/B-cell ratio was observed, with a disproportionate increase in total B cells. In summary, intrahepatic increases in Tregs, biochemical remission, and regeneration could be induced by splenectomy in the late stage of emAIH.

Role of endothelial cells in graft-versus-host disease

To date, the only curative treatment for high-risk or refractory hematologic malignancies non-responsive to standard chemotherapy is allogeneic hematopoietic transplantation (allo-HCT). Acute graft-versus-host disease (GVHD) is a donor T cell-mediated immunological disorder that is frequently fatal and the leading cause of non-relapse mortality (NRM) in patients post allo-HCT. The pathogenesis of acute GVHD involves recognition of minor and/or major HLA mismatched host antigens by donor T cells followed by expansion, migration and finally end-organ damage due to combination of inflammatory cytokine secretion and direct cytotoxic effects. The endothelium is a thin layer of endothelial cells (EC) that line the innermost portion of the blood vessels and a key regulator in vascular homeostasis and inflammatory responses. Endothelial cells are activated by a wide range of inflammatory mediators including bacterial products, contents released from dying/apoptotic cells and cytokines and respond by secreting cytokines/chemokines that facilitate the recruitment of innate and adaptive immune cells to the site of inflammation. Endothelial cells can also be damaged prior to transplant as well as by alloreactive donor T cells. Prolonged EC activation results in dysfunction that plays a role in multiple post-transplant complications including but not limited to veno-occlusive disease (VOD), transplant associated thrombotic microangiopathy (TA-TMA), and idiopathic pneumonia syndrome. In this mini review, we summarize the biology of endothelial cells, factors regulating EC activation and the role of ECs in inflammation and GVHD pathogenesis.

Liver-resident memory T cells: life in lockdown

A subset of memory T cells has been identified in the liver with a tissue-resident profile and the capacity for long-term 'lockdown'. Here we review how they are retained in, and adapted to, the hepatic microenvironment, including its unique anatomical features and metabolic challenges. We describe potential interactions with other local cell types and the need for a better understanding of this complex bidirectional crosstalk. Pathogen or tumour antigen-specific tissue-resident memory T cells (T_RM) can provide rapid frontline immune surveillance; we review the evidence for this in hepatotropic infections of major worldwide importance like hepatitis B and malaria and in liver cancers like hepatocellular carcinoma. Conversely, T_RM can be triggered by pro-inflammatory and metabolic signals to mediate bystander tissue damage, with an emerging role in a number of liver pathologies. We discuss the need for liver sampling to gain a window into these compartmentalised T cells, allowing more accurate disease monitoring and future locally targeted immunotherapies.

The influence of baseline characteristics on the efficacy of immune checkpoint inhibitors for advanced lung cancer: A systematic review and meta-analysis

Purpose: To investigate the impact of different baseline characteristics on the efficacy of immune checkpoint inhibitors (ICIs) for advanced lung cancer.

Methods: In order to identify eligible randomized controlled trials (RCTs), a systematic search was conducted in PubMed, Embase, Web of Science, and Scopus Cochrane Library databases. The primary outcomes were hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS). To explore the potential interaction during the administration of ICI, patients were stratified by baseline characteristics.

Results: The meta-analysis included 24 RCTs. ① Compared with non-ICI therapy, patients with lung cancer benefitted more from immunotherapy (HR, 0.78; p &lt; 0.0001). ② Patients without liver metastases could get more survival benefits than those with liver metastases (HR, 1.20; p = 0.0139). Similar outcomes were also observed in the following subgroups: small-cell lung cancer (HR, 1.20; p = 0.0433), subsequent line (HR, 1.40; p = 0.0147), and ICI monotherapy (HR, 1.40; p = 0.0147). ③ Subgroup analysis showed that tumor type affected the efficacy of immunotherapy in patients with brain metastases (HR, 0.72 vs. 1.41; interaction, p &lt; 0.01). Among patients with smoking history (HR, 0.87 vs. 1.23; interaction, p = 0.05) and brain metastases (HR, 0.69 vs. 1.21; interaction, p = 0.05), the type of therapy (i.e., monotherapy or combination therapy) had potential influences on the efficacy of immunotherapy.

Conclusion: Some critical baseline characteristics could indicate the efficacy of ICI therapy. Liver metastasis status could predict the efficacy of ICI therapy for lung cancer. Compared with small-cell lung cancer, patients with brain metastases might have durable OS in non-small-cell lung cancer. The smoking history or brain metastasis status of patients could indicate the potential clinical benefits of monotherapy or combination therapy.

The Efficacy of PD-1/PD-L1 Inhibitors in Patients with Liver Metastasis of Non-Small Cell Lung Cancer: A Real-World Study

BACKGROUND

A controversy exists regarding the efficacy of programmed death-1 (PD-1)/ programmed death ligand-1 (PD-L1) inhibitors for patients with non-small cell lung cancer (NSCLC) and liver metastases. Our study retrospectively evaluated the efficacy of PD-1/PD-L1 inhibitors in NSCLC patients with liver metastases.

METHODS

This retrospective study included 1627 lung cancer patients who received immunotherapy. Among 648 patients who had advanced NSCLC and received PD-1/PD-L1 inhibitors, 61 had liver metastases and 587 did not have. We analyzed patient characteristics, progression-free survival (PFS) and overall survival (OS). An exploratory analysis of biomarkers including CD4, CD8 and CD68 for efficacy in patients with liver metastases was also performed.

RESULTS

In liver metastasis patients receiving PD-1/PD-L1 inhibitors, the objective response rate (ORR) was 29.5%, the disease control rate (DCR) was 72.1%, PFS was 6.4 months and OS was 15.2 months, which were all worse than those of patients without liver metastases (ORR: 35.8%; DCR: 81.8%; PFS: 7.9 months, p = 0.001; OS: 20.6 months, p = 0.008). When compared to non-liver lesions, the ORR (26.2 vs. 39.3%) and DCR (75.4 vs. 88.5%) of liver lesions were lower. During the analysis of PD-L1 expression, 27 PD-L1-positive patients had a longer PFS than 21 patients in the negative group (p = 0.012). Being PD-L1 positive was the independent prognostic indicators for PFS (p = 0.006). Additionally, the PD-L1 and CD8 dual-positive group responded favorably to PD-1/PD-L1 inhibitors.

CONCLUSIONS

PD-1/PD-L1 inhibitors are effective in liver metastasis-NSCLC patients. However, the efficacy is inferior when compared to those of patients without liver metastases. In NSCLC patients with liver metastases, PD-L1 expression and CD8+ T cell infiltration can predict the response of PD-1/PD-L1-directed immunotherapy.

Research Progress on the Microenvironment and Immunotherapy of Advanced Non-Small Cell Lung Cancer With Liver Metastases

Lung cancer is a malignant tumor with the highest morbidity and mortality, and more than 75% of patients are diagnosed at an advanced stage. Liver metastases occur in 20% of non-small cell lung cancer patients, and their prognosis are poor. In recent years, immune checkpoint inhibitor monotherapy and combination therapy have made breakthrough progress in advanced Non-small cell lung cancer (NSCLC) patients. However, compared with the overall population, the liver metastases population was an independent prognostic factor for poor immunotherapy response. Whether and how immunotherapy can work in NSCLC patients with liver metastases is a major and unresolved challenge. Although more and more data have been disclosed, the research progress of NSCLC liver metastasis is still limited. How liver metastasis modulates systemic antitumor immunity and the drug resistance mechanisms of the liver immune microenvironment have not been elucidated. We systematically focused on non-small cell lung cancer patients with liver metastases, reviewed and summarized their pathophysiological mechanisms, immune microenvironment characteristics, and optimization of immunotherapy strategies.

Animal Models for Autoimmune Hepatitis: Are Current Models Good Enough?

Autoimmune liver diseases like autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, and IgG4-related cholangitis are chronic inflammatory diseases of the liver with an autoimmune background. The therapy of autoimmune hepatitis targets the autoreactive immune system and is largely dependent on the use of glucocorticoids and cytostatic drugs. In contrast, the treatment of cholestatic autoimmune liver diseases is restricted to the use of secondary or semi-synthetic bile acids, like ursodeoxycholic acid or obeticholic acid. Although the management of the disease using such drugs works well for the majority of patients, many individuals do not respond to standard therapy. In addition, chronic treatment with glucocorticoids results in well-known side effects. Further, the use of bile acids is a symptomatic therapy that has no direct immunomodulatory effect. Thus, there is still a lot of room for improvement. The use of animal models has facilitated to elucidate the pathogenesis of autoimmune liver diseases and many potential target structures for immunomodulatory therapies have been identified. In this review, we will focus on autoimmune hepatitis for which the first animal models have been established five decades ago, but still a precise treatment for autoimmune hepatitis, as obtainable for other autoimmune diseases such as rheumatoid arthritis or multiple sclerosis has yet to be introduced. Thus, the question arises if our animal models are too far from the patient reality and thus findings from the models cannot be reliably translated to the patient. Several factors might be involved in this discrepancy. There is first and foremost the genetic background and the inbred status of the animals that is different from human patients. Here the use of humanized animals, such as transgenic mice, might reduce some of the differences. However, there are other factors, such as housing conditions, nutrition, and the microbiome that might also play an important role. This review will predominantly focus on the current status of animal models for autoimmune hepatitis and the possible ways to overcome discrepancies between model and patient.

The Crosstalk Between Liver Sinusoidal Endothelial Cells and Hepatic Microenvironment in NASH Related Liver Fibrosis

Chronic liver injury can be caused by many factors, including virus infection, alcohol intake, cholestasis and abnormal fat accumulation. Nonalcoholic steatohepatitis (NASH) has become the main cause of liver fibrosis worldwide. Recently, more and more evidences show that hepatic microenvironment is involved in the pathophysiological process of liver fibrosis induced by NASH. Hepatic microenvironment consists of various types of cells and intercellular crosstalk among different cells in the liver sinusoids. Liver sinusoidal endothelial cells (LSECs), as the gatekeeper of liver microenvironment, play an irreplaceable role in the homeostasis and alterations of liver microenvironment. Many recent studies have reported that during the progression of NASH to liver fibrosis, LSECs are involved in various stages mediated by a series of mechanisms. Therefore, here we review the key role of crosstalk between LSECs and hepatic microenvironment in the progression of NASH to liver fibrosis (steatosis, inflammation, and fibrosis), as well as promising therapeutic strategies targeting LSECs.

Innate immune surveillance of the circulation: A review on the removal of circulating virions from the bloodstream

Many viruses utilize the lymphohematogenous route for dissemination; however, they may not freely use this highway unchecked. The reticuloendothelial system (RES) is an innate defense system that surveys circulating blood, recognizing and capturing viral particles. Examination of the literature shows that the bulk of viral clearance is mediated by the liver; however, the precise mechanism(s) mediating viral vascular clearance vary between viruses and, in many cases, remains poorly defined. Herein, we summarize what is known regarding the recognition and capture of virions from the circulation prior to the generation of a specific antibody response. We also discuss the consequences of viral capture on viral pathogenesis and the fate of the captor cell. Finally, this understudied topic has implications beyond viral pathogenesis, including effects on arbovirus ecology and the application of virus-vectored gene therapies.

Harnessing the liver to induce antigen-specific immune tolerance

Autoimmune diseases develop when the adaptive immune system attacks the body’s own antigens leading to tissue damage. At least 80 different conditions are believed to have an autoimmune aetiology, including rheumatoid arthritis, type I diabetes, multiple sclerosis or systemic lupus erythematosus. Collectively, autoimmune diseases are a leading cause of severe health impairment along with substantial socioeconomic costs. Current treatments are mostly symptomatic and non-specific, and it is typically not possible to cure these diseases. Thus, the development of more causative treatments that suppress only the pathogenic immune responses, but spare general immunity is of great biomedical interest. The liver offers considerable potential for development of such antigen-specific immunotherapies, as it has a distinct physiological capacity to induce immune tolerance. Indeed, the liver has been shown to specifically suppress autoimmune responses to organ allografts co-transplanted with the liver or to autoantigens that were transferred to the liver. Liver tolerance is established by a unique microenvironment that facilitates interactions between liver-resident antigen-presenting cells and lymphocytes passing by in the low blood flow within the hepatic sinusoids. Here, we summarise current concepts and mechanisms of liver immune tolerance, and review present approaches to harness liver tolerance for antigen-specific immunotherapy.