Liver Inflammation and Hepatobiliary Cancers.

Immune regulation has an important role in cancer development, particularly in organs with continuous exposure to environmental pathogens, such as the liver and gastrointestinal tract. Chronic liver inflammation can lead to the development of hepatobiliary cancers, namely hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), or combined HCC (cHCC)-CCA. In this review, we discuss the link between oxidative stress and the hepatic immune compartments, as well as how these factors trigger hepatocyte damage, proliferation, and eventually cancer initiation and its sustainment. We further give an overview of new anticancer therapies based on immunomodulation.

Natural Killer T Cells in Various Mouse Models of Hepatitis.

Natural killer T (NKT) cells are a key component of innate immunity. Importantly, a growing body of evidence indicates that NKT cells play an integral role in various acute and chronic liver injuries. NKT cells participate in the progression of an injury through the secretion of cytokines, which promote neutrophil infiltration and enhance Fas ligand (FasL) and granzyme-mediated NKT cytotoxic activity. Therefore, examining the role of NKT cells in hepatic disease is critical for a comprehensive understanding of disease pathogenesis and may provide insight into novel approaches for treatment. For more than a century, mouse models that imitate the physiopathological conditions of human disease have served as a critical tool in biological and medical basic research, including studies of liver disease. Here, we review the role of NKT cells in various mouse models of hepatitis.

Two Faces of Neutrophils in Liver Disease Development and Progression.

Neutrophils, the most abundant type of leukocyte in human blood, play a major role in host defense against invading pathogens and in sterile injury. Neutrophil infiltration is characteristic of inflammation because of its antimicrobial and cytotoxic activities. Neutrophils also actively participate in the resolution of inflammation and subsequent tissue repair by acting as a critical mediator between the inflammation and resolution phases of tissue damage. However, neutrophils that are consistently exposed to inflammatory conditions lose their self-resolving capabilities and maintain an inflammatory phenotype, further exacerbating tissue damage. The current review describes how neutrophils interact with tissue microenvironments and acquire disease-specific phenotypes under chronic inflammatory conditions. Here, we aim to provide a better understanding of neutrophil-mediated pathogenesis of various liver diseases.

Differences in autoimmune hepatitis based on inflammation localization.

Histopathology is essential for the diagnosis and evaluation of disease activity of autoimmune hepatitis (AIH). We aimed to elucidate the characteristics of AIH from the localization of inflammation. We re-evaluated a nationwide survey that was performed in Japan in 2018 of AIH patients diagnosed between 2014 and 2017. A total of 303 patients were enrolled, and the clinical and treatment characteristics were compared between the patients with predominantly portal inflammation (230 patients) or lobular inflammation (73 patients). AIH patients with lobular inflammation had a higher probability of being diagnosed with acute hepatitis than those with portal inflammation. Liver enzyme levels were higher in patients with lobular inflammation, whereas immunoglobulin G levels were higher in patients with portal inflammation. The prevalence of an alanine aminotransferase level < 30 U/L after 6 months of treatment was significantly higher in patients with lobular inflammation than in those with portal inflammation (81.7% vs. 67.3%, P = 0.046). The localization of inflammation may be useful for evaluating the onset of AIH.

Defining virus-specific CD8+ TCR repertoires for therapeutic regeneration of T cells against chronic hepatitis E.

BACKGROUND & AIMS: Immunosuppressed patients with chronic hepatitis E virus infection (cHEV), who are ineligible or have failed current treatment with off-label ribavirin, are a potential target population for T cell-based therapy. T cell responses are important for viral control. Herein, we aimed to identify human leukocyte antigen (HLA)-A2 restricted HEV-specific CD8+ T cell epitopes and T cell receptors (TCR) targeting these epitopes, as the basis for a redirected TCR treatment approach for patients with cHEV. METHODS: HEV genotype 3 overlapping peptide pools were used to screen HEV-specific CD8+ T cell immune responses in HLA-A2+ patients with acute HEV infection and healthy donors, by intracellular cytokine staining. CD8+ T cells targeting the identified epitopes were sorted for sequencing of the TCR repertoires by next generation sequencing. Messenger RNA encoding these TCRs were introduced into lymphocytes of healthy donors and patients with cHEV through TCR redirection. TCR-engineered lymphocytes were evaluated for Dextramer®-binding capacity, target sensitivity and cytotoxicity against peptide-loaded T2 cells. RESULTS: HEV-specific responses were observed across open reading frame (ORF)1 and ORF2 of the HEV genome in patients with acute resolving HEV infection. HLA-A2-restricted HEV-specific CD8+ T cell epitopes targeting the HEV RNA helicase and RNA-dependent RNA polymerase were selected for functional studies. Introduction of HEV-specific TCRs into lymphocytes of immunocompetent donors and patients with chronic hepatitis E enabled the lymphocytes to bind HEV Dextramers, secrete multiple cytokines and exert cytotoxicity in a target-specific manner. CONCLUSION: We identified TCRs that target HEV-specific CD8+ T cell epitopes, and characterized their immune properties, which may have clinical potential in future T cell-based therapy. LAY SUMMARY: Patients who are immunosuppressed are vulnerable to developing chronic liver disease following infection with hepatitis E virus (HEV). To-date, there is no approved therapy for chronic hepatitis E. Interferon-α and ribavirin are off-label treatment options, but their applications are limited by side effects. Thus, immunotherapy, more specifically T cell-based therapy, may be an alternative approach. We designed T cell receptor-engineered T cells that effectively conferred immune cells, taken from patients with chronic hepatitis E, with the ability to recognize virus-specific epitopes and mediate killing of target cells in vitro.

Effects of dual plasma molecular adsorption system on liver function, electrolytes, inflammation, and immunity in patients with chronic severe hepatitis.

BACKGROUND: To investigate the effects of dual plasma molecular adsorption system (DPMAS) on the liver function, electrolytes, inflammation, and immunity in patients with chronic severe hepatitis (CSH). METHODS: Total of 162 patients with CSH treated in our hospital from March 2016 to December 2018 were enrolled and equally randomly divided into control group (n = 81) and observation group (n = 81). The patients in control group were treated with plasma exchange, while those in observation group were additionally treated with DPMAS based on the treatment in control group. The liver function, electrolytes, inflammation, and immunity were evaluated and compared between the two groups. RESULTS: After treatment, the liver function indexes in observation group were significantly favorable compared with those in control group, with the reduction in TBIL, DBIL, ALT, and rise of CHE levels (P < 0.05). The levels of K+ , Na+ , Cl- , and Ca2+ in both groups were significantly improved after treatment (P < 0.05), although there were no significant differences between the two groups (P > 0.05). The levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in both groups declined after treatment compared with those before treatment, and those levels in observation group were higher than that in control group (P < 0.05). After treatment, the levels of cluster of differentiation 3+ (CD3+ ), CD4+ , and CD4+ /CD8+ were higher in observation group than those in control group, with decreasing level of CD8+ (P < 0.05). CONCLUSION: Dual plasma molecular adsorption system can effectively improve the liver function, effectively correct the electrolyte disorders, reduce the inflammatory response, and adjust the immunity in patients with CSH.

Chronic Hepatitis E is associated with cholangitis.

BACKGROUND AND AIMS: Sporadic hepatitis E is an emerging indigenous disease in Europe induced by genotype 3 of the virus. While the disease takes an acute self-limited course in immunocompetent individuals, under immunocompromised conditions chronic hepatitis E might develop. The histology of chronic hepatitis E has not been described in detail systematically. METHODS: Liver biopsies from 19 immunosuppressed patients with chronic hepatitis E were collected: 17 were organ transplant recipients, one had a CD4-deficiency and one had received steroid therapy because of ulcerative colitis. Biopsies were processed with standard stains. Evaluation of histologic activity and fibrosis was performed according to Ishak. Additionally, immunohistochemistry with antibodies directed against open reading frame 2 and 3 of the virus was performed and liver biopsies were tested for hepatitis E virus RNA. RESULTS: Biochemical data showed an increase in alanine transaminase, aspartate transaminase, gamma-glutamyl transferase and total bilirubin. Histopathology displayed typical features of chronic hepatitis with mild to moderate activity. The number of polymorphonuclear leucocytes was considerably increased and all patients had a florid cholangitis that presented as a destructive form in five of them. Hepatocytes and bile duct epithelia stained positive for hepatitis E virus by immunohistochemistry. CONCLUSIONS: Chronic hepatitis E in immunocompromised individuals runs a similar course as hepatitis B and C and shows similar histopathology. However, the presence of destructive cholangitis in some cases accompanied by an increased number of polymorphonuclear leucocytes is markedly different. Immunohistochemically the virus is present in bile duct epithelia, seemingly the cause for cholangitis.

Modeling the Chronification Tendency of Liver Infections as Evolutionary Advantage.

Here, we discuss how the tendency of a liver infection to chronify can be seen as an evolutionary advantage for infected individuals. For this purpose, we present a set of reaction-diffusion equations as a mathematical model of viral liver infections, which allows chronic and acute courses of the liver infection. We introduce a cumulative wealth function, and finally, we show that an immune response favoring the chronification is evolutionary advantageous at the same time.

Clinical features and determinants of chronicity in hepatitis E virus infection.

Hepatitis E virus (HEV) has traditionally been associated with an acute, self-limiting hepatitis and is not known to have any chronic sequelae. HEV genotypes 1 and 2, which are human pathogens, have been associated with this self-limiting presentation, in both sporadic and epidemic settings. HEV genotype 3, which is zoonotically transmitted, is increasingly being reported as a cause of chronic infection in immunocompromised patients. These include patients with solid organ transplants, patients receiving chemotherapy for haematologic malignancies and patients infected with HIV. Chronic infection is associated with rapidly progressing liver disease and extrahepatic manifestations including neurologic disorders. We review the clinical manifestations of chronic HEV infection and discuss factors determining persistence and chronicity of HEV.

Systemic inflammation and immune cell phenotypes are associated with neuro-psychiatric symptoms in patients with chronic inflammatory liver diseases.

BACKGROUND & AIMS: Chronic inflammatory liver diseases are frequently associated with neuropsychiatric and cognitive dysfunctions. We hypothesized that symptomatic patients may show altered levels of soluble inflammatory mediators (SIMs) as well as changes in immune cell phenotypes. METHODS: A comprehensive immune-phenotyping including investigation of 50 SIMs as well as ex-vivo phenotypes of NK-cells, CD3+, CD4+, CD8+ and regulatory T cells in 40 patients with viral and autoimmune chronic liver diseases was performed. The patients' cognitive functions were assessed using an extensive battery of neuropsychological testing. RESULTS AND CONCLUSION: Overall, our data indicate that while SIMs are significantly up-regulated, NK- and T-cells are less-activated in patients with neuropsychiatric symptoms accompanying chronic inflammatory liver diseases compared to patients without these symptoms. Moreover, HCV patients showed a unique pattern of immune alterations as compared to patients with HBV, autoimmune hepatitis and primary biliary cirrhosis. These findings hint towards potential mechanisms explaining these symptoms in patients with chronic liver diseases.

CTLA­4 interferes with the HBV­specific T cell immune response (Review).

Hepatitis B virus (HBV) infection is a major cause of hepatic inflammation. Successful HBV clearance in patients is associated with sustained viral control by effector T cells. Compared with acute hepatitis B, chronic HBV infection is associated with the depletion of T cells, resulting in weak or absent virus­specific T cells reactivity, which is described as 'exhaustion'. This exhaustion is characterized by impaired cytokine production and sustained expression of multiple coinhibitory molecules. Cytotoxic T lymphocyte­associated antigen­4 (CTLA­4) is one of many coinhibitory molecules that can attenuate T cell activation by inhibiting costimulation and transmitting inhibitory signals to T cells. Persistent HBV infection results in the upregulation of CTLA­4 on hepatic CD8+ T cells. This prompts CD8+ T cell apoptosis, and the activation of cytotoxic T lymphocytes is blocked. Similar to CD8+ T cells, CD4+ T helper (Th) cell proliferation is hindered following CTLA­4 upregulation. In addition, the differentiation of CD4+ Th is polarized toward the Th2/peripherally­inducible T regulatory cell types, increasing the levels of anti­inflammatory cytokines. Conversely, the activation of proinflammatory cells (Th1 and follicular helper T) is blocked, and the levels of proinflammatory cytokines decline. This review summarizes the current literature relevant to T cell exhaustion in patients with HBV­related chronic hepatitis, and discusses the roles of CTLA­4 in T cell exhaustion.

Immunotherapy of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most deadly and rapidly evolving cancers worldwide. The current systemic treatment strategies in advanced tumor stages remain limited despite promising preclinical and early-phase clinical results for some compounds, highlighting an unmet clinical need. Since the majority of HCCs evolve in the background of a chronic inflammatory liver damage, HCCs can be considered a paradigm for inflammation-induced cancers, which renders immunotherapeutic strategies particularly promising for this tumor entity. Consequently, an improved understanding of key oncogenic and immune response signaling pathways as well as increasing appreciation of the diseased microenvironment for HCC initiation and progression has led to the development of a diverse range of immune-oncological interventions during the last decade. Besides oncolytic viruses, vaccines, or immune cell infusions, first results from early-phase clinical trials particularly encourage the use of immune checkpoint inhibitors against PD-1/PD-L1 and CTLA-4 for HCC. In this review, we delineate the current clinical and preclinical landscape of immunotherapies in HCC, critically discuss recent findings from clinical trials and outline future perspectives in the field of liver cancer.

Biliary Tract Cancer: Implicated Immune-Mediated Pathways and Their Associated Potential Targets.

There is a well-established link between biliary tract cancers (BTC) and chronic inflammatory conditions such as primary sclerosing cholangitis, chronic cholecystitis, chronic cholelithiasis, liver fluke-associated infestations, and chronic viral hepatic infections. These associated risk factors highlight the potential for development of immune-modulatory agents in this poor-prognostic disease group with limited treatment options. Clinical trials have evaluated the role of immune cells, inflammatory biomarkers, vaccines, cytokines, adoptive cell therapy, and immune checkpoint inhibitors in patients with BTC. Although these have demonstrated the importance of the immune environment in BTC, currently none of the immune-based therapies have been approved for use in this disease group. The role of immunomodulatory agents is a developing field and has yet to find its way 'from bench to bedside' in BTC.

Role of relevant immune-modulators and cytokines in hepatocellular carcinoma and premalignant hepatic lesions.

AIM: To assess the levels of different immune modulators in patients with hepatocellular carcinoma (HCC), in relation to other hepatic diseases. METHODS: Eighty-eight patients were included in the current study and represented patients with HCC (20), liver cirrhosis (28) and chronic hepatitis (CH; 25), and normal controls (NC; 15). Peripheral blood was isolated for immunophenotyping of active myeloid dendritic cells (mDCs; CD1c and CD40), mature inactive myeloid cells (CD1c and HLA), active plasmacytoid cells (pDCs; CD303 and CD40), mature inactive pDCs (CD30 and HLA), active natural killer (NK) cells (CD56 and CD161), active NK cells (CD56 and CD314) and inactive NK cells (CD56 and CD158) was done by flow cytometry. Serum levels of interleukin (IL)-2, IL-10, IL-12, IL-1ß, interferon (IFN)-α, IFN-γ and tumor necrosis factor (TNF)-αR2 were assessed by ELISA. RESULTS: Active mDCs (CD1C+/CD40+) and inactive mDCs (CD1c+/HLA+) were significantly decreased in HCC patients in relation to NC (P < 0.001). CD40+ expression on active pDCs was decreased in HCC patients (P < 0.001), and its level was not significantly changed among other groups. Inactive pDCs (CD303+/HLA+), inactive NKs (CD56+/CD158+) and active NKs (CD56+/CD161+) were not statistically changed among the four groups studied; however, the latter was increased in CH (P < 0.05). NKG2D was statistically decreased in HCC, CH and cirrhosis (P < 0.001), and it was not expressed in 63% (12/20) of HCC patients. There was significant decrease of IL-2, IFN-α and IFN-γ (P < 0.001), and a significant increase in IL-10, IL-1ß, and TNF-αR2 (P <0.01, P < 0.001 and P < 0.001; respectively) in HCC patients. There was inverted correlation between IL-12 and IL-1ß in HCC (r = -0.565, P < 0.01), with a strong correlation between pDCs (CD303+/CD40+) and NKs (CD56+/CD161+; r = 0.512, P < 0.05) as well as inactive mDCs (CD1c+/HLA+) and inactive NK cells (CD56+/CD158+; r = 0.945, P < 0.001). CONCLUSION: NKG2D, CD40, IL-2 and IL-10 are important modulators in the development and progression of HCC.

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

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

Treating chronic hepatitis E: when is enough enough?

We present a 38-year-old white British man who was taking long-term immunosuppressive medication following kidney transplantation. On routine review, he was noted to have an isolated and asymptomatic rise in alanine aminotransferase. After thorough investigation, he was found to have positive IgM and IgG serology to hepatitis E virus-and given the duration of his transaminitis, he was determined to have chronic hepatitis E infection. Treatment options were complicated by the presence of his kidney transplant, by chronic anaemia and by his wish for concomitant fertility treatment. Ribavirin therapy was instituted with a dramatic and immediate drop in serum viral load, although stool viraemia persisted. No clear protocols guide duration of treatment in chronic hepatitis E infection, but protracted faecal virus shedding predicts viral recrudescence, and treatment should continue at least until the stool is clear of virus.

The signature of liver cancer in immune cells DNA methylation.

Background: The idea that changes to the host immune system are critical for cancer progression was proposed a century ago and recently regained experimental support. Results: Herein, the hypothesis that hepatocellular carcinoma (HCC) leaves a molecular signature in the host peripheral immune system was tested by profiling DNA methylation in peripheral blood mononuclear cells (PBMC) and T cells from a discovery cohort (n = 69) of healthy controls, chronic hepatitis, and HCC using Illumina 450K platform and was validated in two validation sets (n = 80 and n = 48) using pyrosequencing. Conclusions: The study reveals a broad signature of hepatocellular carcinoma in PBMC and T cells DNA methylation which discriminates early HCC stage from chronic hepatitis B and C and healthy controls, intensifies with progression of HCC, and is highly enriched in immune function-related genes such as PD-1, a current cancer immunotherapy target. These data also support the feasibility of using these profiles for early detection of HCC.