Inflammatory Phenotype of Intrahepatic Sulfatide-Reactive Type II NKT Cells in Humans With Autoimmune Hepatitis

Background: Natural Killer T (NKT) cells are CD1d-restricted innate-like T cells that can rapidly release stored cytokines upon recognition of lipid antigens. In mice, type I NKT cells seem to promote liver inflammation, whereas type II NKT cells seem to restrict hepatitis. Here, we aimed at characterizing the role of human type I and type II NKT in patients with autoimmune hepatitis (AIH).Methods: NKT cells were analyzed by flow cytometry in peripheral blood and liver of AIH patients and control groups. α-galactosylceramide-loaded or sulfatide-loaded tetramers were used to detect type I or II NKT cells, respectively. Hepatic CD1d was stained by in situ-hybridization of liver biopsies.Results and Conclusions: Type II NKT cells were more prevalent in human peripheral blood and liver than type I NKT cells. In AIH patients, the frequency of sulfatide-reactive type II NKT cells was significantly increased in peripheral blood (0.11% of peripheral blood leukocytes) and liver (3.78% of intrahepatic leukocytes) compared to healthy individuals (0.05% and 1.82%) and patients with drug-induced liver injury (0.06% and 2.03%; p < 0.05). Intrahepatic type II NKT cells of AIH patients had a different cytokine profile than healthy subjects with an increased frequency of TNFα (77.8% vs. 59.1%, p < 0.05), decreased IFNγ (32.7% vs. 63.0%, p < 0.05) and a complete lack of IL-4 expressing cells (0% vs. 2.1%, p < 0.05). T cells in portal tracts expressed significantly more CD1d-RNA in AIH livers compared to controls. This study supports that in contrast to their assumed protective role in mice, human intrahepatic, sulfatide-reactive type II NKT cells displayed a proinflammatory cytokine profile in patients with AIH. Infiltrating T cells in portal areas of AIH patients overexpressed CD1d and could thereby activate type II NKT cells

Inflammatory Mechanisms Underlying Nonalcoholic Steatohepatitis and the Transition to Hepatocellular Carcinoma

Nonalcoholic fatty liver disease (NAFLD) is a rising chronic liver disease and comprises a spectrum from simple steatosis to nonalcoholic steatohepatitis (NASH) to end-stage cirrhosis and risk of hepatocellular carcinoma (HCC). The pathogenesis of NAFLD is multifactorial, but inflammation is considered the key element of disease progression. The liver harbors an abundance of resident immune cells, that in concert with recruited immune cells, orchestrate steatohepatitis. While inflammatory processes drive fibrosis and disease progression in NASH, fueling the ground for HCC development, immunity also exerts antitumor activities. Furthermore, immunotherapy is a promising new treatment of HCC, warranting a more detailed understanding of inflammatory mechanisms underlying the progression of NASH and transition to HCC. Novel methodologies such as single-cell sequencing, genetic fate mapping, and intravital microscopy have unraveled complex mechanisms behind immune-mediated liver injury. In this review, we highlight some of the emerging paradigms, including macrophage heterogeneity, contributions of nonclassical immune cells, the role of the adaptive immune system, interorgan crosstalk with adipose tissue and gut microbiota. Furthermore, we summarize recent advances in preclinical and clinical studies aimed at modulating the inflammatory cascade and discuss how these novel therapeutic avenues may help in preventing or combating NAFLD-associated HCC

Nuclear Receptors Linking Metabolism, Inflammation, and Fibrosis in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) and its progressive form nonalcoholic steatohepatitis (NASH) comprise a spectrum of chronic liver diseases in the global population that can lead to end-stage liver disease and hepatocellular carcinoma (HCC). NAFLD is closely linked to the metabolic syndrome, and comorbidities such as type 2 diabetes, obesity and insulin resistance aggravate liver disease, while NAFLD promotes cardiovascular risk in affected patients. The pathomechanisms of NAFLD are multifaceted, combining hepatic factors including lipotoxicity, mechanisms of cell death and liver inflammation with extrahepatic factors including metabolic disturbance and dysbiosis. Nuclear receptors (NRs) are a family of ligand-controlled transcription factors that regulate glucose, fat and cholesterol homeostasis and modulate innate immune cell functions, including liver macrophages. In parallel with metabolic derangement in NAFLD, altered NR signaling is frequently observed and might be involved in the pathogenesis. Therapeutically, clinical data indicate that single drug targets thus far have been insufficient for reaching patient-relevant endpoints. Therefore, combinatorial treatment strategies with multiple drug targets or drugs with multiple mechanisms of actions could possibly bring advantages, by providing a more holistic therapeutic approach. In this context, peroxisome proliferator-activated receptors (PPARs) and other NRs are of great interest as they are involved in wide-ranging and multi-organ activities associated with NASH progression or regression. In this review, we summarize recent advances in understanding the pathogenesis of NAFLD, focusing on mechanisms of cell death, immunometabolism and the role of NRs. We outline novel therapeutic strategies and discuss remaining challenges

Transient elastography in autoimmune hepatitis: Timing determines the impact of inflammation and fibrosis

Background & Aims: There is an unmet need for the non-invasive monitoring of fibrosis progression in patients with autoimmune hepatitis (AIH). The aim of this study was to assess the diagnostic performance of transient elastography in patients with AIH and to investigate the impact of disease activity on its diagnostic accuracy. Methods: Optimal cut-offs were defined in a prospective pilot study (n = 34) and the diagnostic performance of transient elastography validated in an independent second cohort (n = 60). To explore the impact of disease activity on liver stiffness, patients were stratified according to biochemical response and the time interval between start of immunosuppression and transient elastography. Results: Liver stiffness strongly correlated with histological fibrosis stage (pilot study: rho = 0.611, p <0.001; validation cohort: rho = 0.777, p <0.0001). ROC curves defined an area under the receiver operating curve of 0.95 for diagnosing cirrhosis at the optimal cut-off of 16 kPa. The performance of transient elastography was impaired when patients were analysed in whom transient elastography was performed within 3 months from start of treatment. In this setting, liver stiffness correlated with histological grading (rho = 0.558, p = 0.001), but not with staging. In contrast, using the cut-off of 16 kPa, the accuracy for diagnosing cirrhosis was excellent in patients treated for 6 months or longer (area under the receiver operating curve 1.0). Conclusions: Liver inflammation has a major impact on liver stiffness in the first months of AIH treatment. However, transient elastography has an excellent diagnostic accuracy for separating severe from non-severe fibrosis after 6 months of immunosuppressive treatment. Lay summary: Transient elastography is a special ultrasound scan, which assesses liver stiffness as a surrogate marker for liver fibrosis/scarring. Transient elastography has been shown to be a reliable non-invasive method to assess liver fibrosis in various chronic liver diseases, it takes less than 5 min and has a high patient acceptance. The current study validated for the first time this technique in a large cohort of patients with autoimmune hepatitis (AIH) and demonstrates that it is a reliable tool to detect liver fibrosis in treated AIH. For the monitoring of potential disease progression under treatment, the validation of liver stiffness as non-invasive marker of liver fibrosis will greatly improve patient care in autoimmune hepatitis. (C) 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved

Risk of endoscopic biliary interventions in primary sclerosing cholangitis is similar between patients with and without cirrhosis.

BACKGROUND:Endoscopic retrograde cholangiography (ERC) is a mainstay of therapy in patients with primary sclerosing cholangitis (PSC) and obstructive cholestasis. Patients with liver cirrhosis have an increased risk of surgical complications and are more susceptible to infections. Since PSC often progresses to cirrhosis, we aimed to assess whether ERC is associated with increased risk of complications in patients with PSC and cirrhosis. METHODS:Out of 383 patients with PSC, 208 patients received endoscopic treatment between 2009-2017. Seventy patients had cirrhosis when ERC was performed and 138 patients had no signs of cirrhosis. Overall, 663 ERC procedures were analysed, with 250 ERC in patients with cirrhosis and 413 ERC in patients without cirrhosis. Data were analysed retrospectively from a prospectively acquired database using repeated measures logistic regression. RESULTS:Overall, 40 procedure-related complications were documented in 663 ERC interventions (6%). The rate of complications was similar between patients with and without cirrhosis (4.4% vs. 7.0%). First-time ERC was associated with a higher risk of complications (17.5% vs. 4.9%). Biliary sphincterotomy, stent placement and female sex, but not presence of liver cirrhosis, were identified as risk factors for overall complications in multivariate analysis. Patients without cirrhosis showed a significant decline of ALP and bilirubin levels after the first two interventions. In contrast, in patients with cirrhosis, ALP and bilirubin levels did not significantly decline after ERC. CONCLUSIONS:In patients with PSC, cirrhosis was not a risk factor for post-ERC complications. Therefore, cirrhosis should not preclude endoscopic intervention in patients with clear clinical indication