Immune Response and Immunolmodulation in Chronic Hepatiitis B Virus Infection

Despite the presence of an effective vaccine since 1982, chronic hepatitis B virus infection (CHB) still ranks among the highest causes of mortality from infectious diseases worldwide. The studies presented in this thesis were performed to get a better insight into the anti-viral immune response after hepatitis B virus (HBV) infection, and to identify factors in this immune response that contribute to persistent disease. Dendritic cells (DC) play an important role in the induction of anti- viral immune responses. In this thesis we show that two important blood precursor DC, myeloid DC and plasmacytoid DC, are functionally impaired in patients with chronic hepatitis B and this might be an important mechanism by which HBV evades an adequate immune response, leading to viral persistence and disease chronicity. Information about character and grade of the intrahepatic immune response in viral hepatitis is important for evaluation of disease stage and effect of therapy. Complications like haemorrhage provide a limitation to frequently performing standard tissue needle biopsies. The Fine-needle-aspiration-biopsy (FNAB) is an easy and atraumatic alternative and we show that flow cytometry of fine-needle-aspiration- biopsy of the liver allows reliable analysis of lymphocytes obtained from the intrahepatic compartment, in patients with viral hepatitis. Subsequently, the FNAB is used to show that there likely is an important role for intrahepatic HBV-specific CD8+ T-cells in clearing acute HBV infection. Furthermore, we have attempted to boost the impaired T-cell responses in patients with chronic HBV infection, using conventional anti-viral therapy. In in vivo immunization (IVI) of CHB patients, following rapid virus suppression by interferon-lamivudine combination therapy, lamivudine was withdrawn intermittently during continued interferon (IFNα) therapy. Although initially IVI was able to transiently suppress viral replication in two patients with CHB, in a subsequent pilot study the magnitude of the induced T-cell response was insufficient to cause a sustained virological effect in the majority of patients. It is unknown why treatment with IFNα leads to a response in only a minority of patients with chronic HBV. We show that in non-responders and not in responders there was a significant increase in the frequency of regulatory T cells (Treg) and IL-10 secreting cells during treatment with IFNα. Treg depletion resulted in increased proliferation capacity and increased frequencies of HBV-specific INFgamma-producing cells, but did not affect the frequency of IL-10 producing cells measured during the course of the treatment. This study indicates that there may be an important role for Treg in HBV- persistence during and after IFNα therapy

Factors associated with ethnical disparity in overall survival for patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an important cause of cancer-related death worldwide. Ethnical disparity in overall survival has been demonstrated for HCC patients in the United States (U.S.). We aimed to evaluate the contributors to this survival disparity. The SEER database was used to identify HCC patients from 2004 to 2012. Kaplan-Meier curves and Cox proportional hazard models were used to evaluate overall survival by ethnicity and the contributors to ethnical survival disparity. A total of 33 062 patients were included: 15 986 Non-Hispanic Whites, 6535 Hispanic Whites, 4842 African Americans, and 5699 Asians. Compared to Non-Hispanic Whites, African Americans had worse survival (HR, 1.18; 95%CI, 1.14-1.23), while Asians had a better survival (HR, 0.85; 95%CI, 0.82-0.89), and Hispanic Whites had a similar survival (HR, 1.01; 95%CI, 0.97-1.05). Multivariate Cox analysis identified that tumor presentation- and treatment-related factors significantly contributed to the ethnical survival disparity. Especially, tumor size was the most important contributor (HR, 1.11; 95%CI, 1.07-1.16). There is no ethnical survival disparity in patients undergoing liver transplantation and sub-analysis of patients within the Milan criteria for liver transplantation demonstrated no significant survival disparity between African Americans and non-Hispanic Whites in transplantation adjustment analysis (HR, 1.23; 95%CI, 1.11-1.35 in non-adjustment analysis to HR, 1.05; 95%CI, 0.95-1.15 after adjustment). Finally, no important contributor to the superior overall survival in Asians was identified. In conclusion, poor tumor presentation at diagnosis, limited benefit from resection and restricted utilization of liver transplantation are important contributors to poorer survival of African Americans with HCC

Blocking Wnt Secretion Reduces Growth of Hepatocellular Carcinoma Cell Lines Mostly Independent of β-Catenin Signaling

AbstractAberrant activation of Wnt/β-catenin signaling plays a key role in the onset and development of hepatocellular carcinomas (HCC), with about half of them acquiring mutations in either CTNNB1 or AXIN1. However, it remains unclear whether these mutations impose sufficient β-catenin signaling or require upstream Wnt ligand activation for sustaining optimal growth, as previously suggested for colorectal cancers. Using a panel of nine HCC cell lines, we show that siRNA-mediated knockdown of β-catenin impairs growth of all these lines. Blocking Wnt secretion, by either treatment with the IWP12 porcupine inhibitor or knockdown of WLS, reduces growth of most of the lines. Unexpectedly, interfering with Wnt secretion does not clearly affect the level of β-catenin signaling in the majority of lines, suggesting that other mechanisms underlie the growth-suppressive effect. However, IWP12 treatment did not induce autophagy or endoplasmic reticulum (ER) stress, which may have resulted from the accumulation of Wnt ligands within the ER. Similar results were observed for colorectal cancer cell lines used for comparison in various assays. These results suggest that most colorectal and liver cancers with mutations in components of the β-catenin degradation complex do not strongly rely on extracellular Wnt ligand exposure to support optimal growth. In addition, our results also suggest that blocking Wnt secretion may aid in tumor suppression through alternative routes currently unappreciated

Engaging stimulatory immune checkpoint interactions in the tumour immune microenvironment of primary liver cancers – how to push the gas after having released the brake

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the first and second most common primary liver cancer (PLC). For decades, systemic therapies consisting of tyrosine kinase inhibitors (TKIs) or chemotherapy have formed the cornerstone of treating advanced-stage HCC and CCA, respectively. More recently, immunotherapy using immune checkpoint inhibition (ICI) has shown anti-tumour reactivity in some patients. The combination regimen of anti-PD-L1 and anti-VEGF antibodies has been approved as new first-line treatment of advanced-stage HCC. Furthermore, gemcibatine plus cisplatin (GEMCIS) with an anti-PD-L1 antibody is awaiting global approval for the treatment of advanced-stage CCA. As effective anti-tumour reactivity using ICI is achieved in a minor subset of both HCC and CCA patients only, alternative immune strategies to sensitise the tumour microenvironment of PLC are waited for. Here we discuss immune checkpoint stimulation (ICS) as additional tool to enhance anti-tumour reactivity. Up-to-date information on the clinical application of ICS in onco-immunology is provided. This review provides a rationale of the application of next-generation ICS either alone or in combination regimen to potentially enhance anti-tumour reactivity in PLC patients

Rapid hepatic clearance of full length CCN-2/CTGF: a putative role for LRP1-mediated endocytosis

CCN-2 (connective tissue growth factor; CTGF) is a key factor in fibrosis. Plasma CCN-2 has biomarker potential in numerous fibrotic disorders, but it is unknown which pathophysiological factors determine plasma CCN-2 levels. The proteolytic amino-terminal fragment of CCN-2 is primarily eliminated by the kidney. Here, we investigated elimination and distribution profiles of full length CCN-2 by intravenous administration of recombinant CCN-2 to rodents. After bolus injection in mice, we observed a large initial distribution volume (454 mL/kg) and a fast initial clearance (120 mL/kg/min). Immunosorbent assay and immunostaining showed that CCN-2 distributed mainly to the liver and was taken up by hepatocytes. Steady state clearance in rats, determined by continuous infusion of CCN-2, was fast (45 mL/kg/min). Renal CCN-2 clearance, determined by arterial and renal vein sampling, accounted for only 12 % of total clearance. Co-infusion of CCN-2 with receptor-associated protein (RAP), an antagonist of LDL-receptor family proteins, showed that RAP prolonged CCN-2 half-life and completely prevented CCN-2 internalization by hepatocytes. This suggests that hepatic uptake of CCN-2 is mediated by a RAP-sensitive mechanism most likely involving LRP1, a member of the LDL-receptor family involved in hepatic clearance of various plasma proteins. Surface plasmon resonance binding studies confirmed that CCN-2 is an LRP1 ligand. Co-infusion of CCN-2 with an excess of the heparan sulphate-binding protamine lowered the large initial distribution volume of CCN-2 by 88 % and reduced interstitial staining of CCN-2, suggesting binding of CCN-2 to heparan sulphate proteoglycans (HSPGs). Protamine did not affect clearance rate, indicating that RAP-sensitive clearance of CCN-2 is HSPG independent. In conclusion, unlike its amino-terminal fragment which is cleared by the kidney, fu

The Yield of Routine Post-Operative Doppler Ultrasound to Detect Early Post-Liver Transplantation Vascular Complications

Early detection of liver transplantation (LT) vascular complications enables timely management. Our aim was to assess if routine Doppler ultrasound (rDUS) improves the detection of hepatic artery thrombosis (HAT), portal vein thrombosis (PVT) and hepatic venous outflow obstruction (HVOO). We retrospectively analysed timing and outcomes, number needed to diagnose one complication (NND) and positive predictive value (PPV) of rDUS on post-operative day (POD) 0,1 and 7 in 708 adult patients who underwent primary LT between 2010–2022. We showed that HAT developed in 7.1%, PVT in 8.2% and HVOO in 3.1% of patients. Most early complications were diagnosed on POD 0 (26.9%), 1 (17.3%) and 5 (17.3%). rDUS correctly detected 21 out of 26 vascular events during the protocol days. PPV of rDUS was 53.8%, detection rate 1.1% and NND was 90.5. Median time to diagnosis was 4 days for HAT and 47 days for PVT and 21 days for HVOO. After intervention, liver grafts were preserved in 57.1%. In conclusion, rDUS protocol helps to detect first week’s vascular events, but with low PPV and a high number of ultrasounds needed.</p