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Immune checkpoint molecules (ICM) are critical in maintaining immunologic homeostasis and participate in preventing or promoting autoimmune disease development. Exploring a large panel of intrahepatic inhibitory and stimulatory ICM is necessary for drawing a general picture of the immune alterations in autoimmune hepatitis (AIH). Here, we performed a multiparametric analysis of ICM, including PD-1, TIM3, LAG3, CTLA-4, OX40 and 4-1BB, and we determined their expression on intrahepatic lymphocyte subsets in untreated and in treated patients with AIH in comparison to normal liver tissue. AIH patient-derived liver tissue revealed the overexpression of ICM, mainly PD-1 and 4-1BB, as well as the strong correlation between PD-1 + CD8 + T-cell abundance and severity of AIH (alanine transaminase and aspartate transaminase levels). Our results show that the ICM play an important role in the loss of immune homeostasis in the liver, providing an attractive approach to investigate their role as targets for effective therapeutic interventions.

Background and aims: Chronic hepatitis B virus (HBV) infection is a major health burden potentially evolving toward cirrhosis and hepatocellular carcinoma. HBV physiopathology is strongly related to the host immunity, yet the mechanisms of viral evasion from immune-surveillance are still misunderstood. The immune response elicited at early stages of viral infection is believed to be important for subsequent disease outcome. Dendritic cells (DCs) are crucial immune sentinels which orchestrate antiviral immunity, which offer opportunity to pathogens to subvert them to escape immunity. Despite the pivotal role of DCs in orientating antiviral responses and determining the outcome of infection, their precise involvement in HBV pathogenesis is not fully explored. Methods: One hundred thirty chronically HBV infected patients and 85 healthy donors were enrolled in the study for blood collection, together with 29 chronically HBV infected patients and 33 non-viral infected patients that were included for liver biopsy collection. In a pioneer way, we investigated the phenotypic and functional features of both circulating and intrahepatic BDCA1+ cDC2, BDCA2+ pDCs, and BDCA3+ cDC1 simultaneously in patients with chronic HBV infection by designing a unique multi-parametric flow cytometry approach. Results: We showed modulations of the frequencies and basal activation status of blood and liver DCs associated with impaired expressions of specific immune checkpoints and TLR molecules on circulating DC subsets. Furthermore, we highlighted an impaired maturation of circulating and hepatic pDCs and cDCs following stimulation with specific TLR agonists in chronic HBV patients, associated with drastic dysfunctions in the capacity of circulating DC subsets to produce IL-12p70, TNFα, IFNα, IFNλ1, and IFNλ2 while intrahepatic DCs remained fully functional. Most of these modulations correlated with HBsAg and HBV DNA levels. Conclusion: We highlight potent alterations in the distribution, phenotype and function of all DC subsets in blood together with modulations of intrahepatic DCs, revealing that HBV may hijack the immune system by subverting DCs. Our findings provide innovative insights into the immuno-pathogenesis of HBV and the mechanisms of virus escape from immune control. Such understanding is promising for developing new therapeutic strategies restoring an efficient immune control of the virus.

We recently identified a histological subtype of hepatocellular carcinoma (HCC), designated as "macrotrabecular-massive" (MTM-HCC) and associated with specific molecular features. In order to assess the clinical relevance of this variant, we investigated its prognostic value in two large series of patients with HCC treated by either surgical resection or radiofrequency ablation (RFA). We retrospectively included 237 HCC surgical samples and 284 HCC liver biopsies from patients treated by surgical resection and RFA, respectively. Histological slides were reviewed by pathologists specialized in liver disease, and the MTM-HCC subtype was defined by the presence of a predominant (>50%) macrotrabecular architecture (more than six cells thick). The main clinical and biological features were recorded at baseline. Clinical endpoints were early and overall recurrence. The MTM-HCC subtype was identified in 12% of the whole cohort (16% of surgically resected samples, 8.5% of liver biopsy samples). It was associated at baseline with known poor prognostic factors (tumor size, alpha-fetoprotein level, satellite nodules, and vascular invasion). Multivariate analysis showed that MTM-HCC subtype was an independent predictor of early and overall recurrence (surgical series: hazard ratio, 3.03; 95% confidence interval, 1.38-6.65; P = 0.006; and 2.76; 1.63-4.67; P < 0.001; RFA series: 2.37; 1.36-4.13; P = 0.002; and 2.19; 1.35-3.54; P = 0.001, respectively). Its prognostic value was retained even after patient stratification according to common clinical, biological, and pathological features of aggressiveness. No other baseline parameter was independently associated with recurrence in the RFA series., Conclusion: The MTM-HCC subtype, reliably observed in 12% of patients eligible for curative treatment, represents an aggressive form of HCC that may require more specific therapeutic strategies. (Hepatology 2018;68:103-112)., (© 2017 by the American Association for the Study of Liver Diseases.)

At the moment of the diagnosis of hepatocellular carcinoma (HCC), 70% of patients have only access to palliative treatments, with very few therapeutic options. Liver immunology is very specific, and liver immunotolerance is particularly developed because of the constant and massive influx of antigens. Deregulation of hepatic immunotolerance is implicated in chronic liver diseases development and particularly in liver carcinogenesis. For these reasons, HCC may be an excellent candidate for anticancer immunotherapies such as immune checkpoint inhibitors targeting CTLA-4 and PD-L1/PD-1. Nonetheless, because of the specific immune environment of the liver and the frequent association of HCC with hepatocellular insufficiency, the safety and the efficacy of these new treatments have to be properly studied in this situation. Thus, multiple phase II and III studies are in progress studying immune checkpoint inhibitor monotherapies, combination of different immunotherapies or local strategies such as transarterial chemoembolization combined with immune checkpoint inhibitors. Currently, only the final results of the tremelimumab phase II and the Nivolumab phase I/II study (CheckMate-040) are available. The latter is promising but need to be confirmed by the ongoing phase III studies to confirm the place of immunotherapy in the treatment of HCC. With many new molecular targets and therapeutic combination, immunotherapy represents a new hope in treating HCC patients although serious evaluation is still needed to confirm its interest., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Major sex differences are observed in the prevalence, intensity, and severity of hepatitis B virus (HBV) infection. Here, we investigated degranulation activity of circulating and intrahepatic natural killer (NK) cells from HBV and HCV chronically infected patients before any treatment ( n = 125). The frequency of CD107 + NK cells in the female liver was significantly higher compared to that in males during chronic HBV infection ( p = 0.002) and correlated with the plasma levels of estradiol (correlation coefficient r = 0.634; p < 0.0001). Our results clearly show sex differences in degranulation activity of intrahepatic NK cells of HBV-infected patients. This probably contributes to the ability of females to better deal with HBV disease.

Background: Chronic liver inflammation and immune/inflammatory response promote hepatocellular carcinoma. The aim of this study was to characterize the immune status of HCV-related cirrhosis in patients with hepatocellular carcinoma (HCV-HCC) as compared to HCV patients without hepatocellular carcinoma., Method: Immune markers (CD3, CD4, CD8, CD20, CD56, TCRγδ, FoxP3) and gene expression profiles (CD8α, CD8β, FoxP3, IL-6, IFN-γ, perforin, RANTES) were analysed in a test cohort by immunohistochemistry and quantitative RT-PCR analysis on serial non-tumorous and tumorous tissues., Results: Immune micro-environment was more inflammatory in HCV-HCC than HCV cirrhotic livers. The number of CD3(+) , CD4(+) , CD8(+) and CD20(+) liver-infiltrating lymphocytes was significantly higher, whereas the number of CD56(+) cells was significantly lower in HCV-HCC compared to HCV cirrhotic parenchyma. These differences were restricted to fibrous septa for CD4(+) and CD20(+) cells and to nodular parenchyma for CD8(+) cells. Gene expressions of CD8α, FoxP3 and RANTES were also significantly higher in HCV-HCC than in HCV cirrhosis. Interestingly, in a large cohort of 63 HCV-HCC patients. The number of CD8(+) cells ≥100/field was associated with significant higher tumour recurrence (P = 0.003) and lower overall survival (P = 0.05) at 5 years., Conclusion: High densities of liver-infiltrating lymphocytes in HCV-HCC cirrhotic parenchyma prevail inflammatory conditions and could contribute to tumorigenesis and tumour recurrence. These results could contribute towards better clinical evaluation of patients susceptible for HCC recurrence after curative surgery., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: To determine if intra-voxel incoherent motion diffusion-weighted imaging (IVIM-DWI) parameters, including free molecular-based (D) and perfusion-related (D*, f) diffusion parameters, correlate with the degree of tumor necrosis and viable tumor in colo-rectal cancer (CRC) metastasis., Materials and Methods: Fifteen patients referred for resection of liver metastases from CRC were retrospectively included in this Institutional Review Board approved study. An IVIM-DWI sequence was performed on a 1.5 Tesla MR imaging system, with 10 b factors (0, 10, 20, 30, 50, 80, 100, 200, 400 and 800 s/mm(2) ). Mean D, D*, f and apparent diffusion coefficient (ADC) values were determined in metastases with a longest diameter above 10 mm. Correlations between the diffusion parameters and the degree of liver tumor necrosis and viable tissue were determined (Spearman)., Results: Correlation between diffusion parameters and histopathological findings was performed in 35 hepatic metastases with a diameter of more than 10 mm (mean size of 17.9 mm; range, 1-68 mm). Both D (r = 0.36; P = 0.035) and ADC (r = 0.4; P = 0.02) correlated with the degree of tumor necrosis but not with viable tumor., Conclusion: ADC variation observed in CRC metastases following systemic chemotherapy reflects a specific increase in free-molecular diffusion (D), in itself correlated to the degree of metastasis necrosis., (Copyright © 2013 Wiley Periodicals, Inc.)

Unlabelled: During hepatogenesis, after the liver has budded out of the endoderm, the hepatoblasts quickly expand and differentiate into either hepatocytes or biliary cells, the latter of which arise only within the ductal plate surrounding the portal vein. Because the Wnt/beta-catenin pathway is involved in liver homeostasis and regeneration and in liver carcinogenesis, we investigated here a role for Wnt/beta-catenin signaling in the embryonic liver. A cyclization recombination (Cre)/locus of X-over P1 (loxP) strategy was chosen to perform adenomatous polyposis coli (Apc) invalidation in order to activate ectopic beta-catenin signaling in hepatoblasts; an appropriate transgenic model expressing the Cre recombinase was used. Phenotypic and immunolocalization studies, together with messenger RNA analyses, by microarray and real-time quantitative polymerase chain reaction approaches were performed on this model during normal hepatogenesis. The loss of Apc allowed beta-catenin activation in the hepatoblasts after the formation of the liver bud and led to embryonic lethality. In this model, the liver became hypoplastic, and hepatocyte differentiation failed, whereas beta-catenin-activated ducts developed and gave rise to fully differentiated bile ducts when transplanted into adult recipient livers. Microarray analyses suggested that beta-catenin plays a role in repressing the hepatocyte genetic program and remodeling the ductal plate. According to these data, in normal embryonic livers, beta-catenin was transiently activated in the nascent bile ducts., Conclusion: We demonstrated a key role for the Wnt/beta-catenin pathway in liver embryonic growth and in controlling the fate of hepatoblasts, preventing them from differentiating toward the hepatocyte lineage, and guiding them to biliary ductal morphogenesis.

The molecular mechanisms by which liver genes are differentially expressed along a portocentral axis, allowing for metabolic zonation, are poorly understood. We provide here compelling evidence that the Wnt/beta-catenin pathway plays a key role in liver zonation. First, we show the complementary localization of activated beta-catenin in the perivenous area and the negative regulator Apc in periportal hepatocytes. We then analyzed the immediate consequences of either a liver-inducible Apc disruption or a blockade of Wnt signaling after infection with an adenovirus encoding Dkk1, and we show that Wnt/beta-catenin signaling inversely controls the perivenous and periportal genetic programs. Finally, we show that genes involved in the periportal urea cycle and the perivenous glutamine synthesis systems are critical targets of beta-catenin signaling, and that perturbations to ammonia metabolism are likely responsible for the death of mice with liver-targeted Apc loss. From our results, we propose that Apc is the liver "zonation-keeper" gene.