SUMMARYMHC class I-peptide tetrameric complexes ('tetramers') have revolutionized the study of antiviral CD8 + T cell responses. They allow accurate quantification of immune responses ex vivo independent of function, with high levels of sensitivity. They have revealed unexpectedly large frequencies of 'memory' T cell responses against viruses such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), and provided information about their phenotypic and functional variation. However, such studies have generally concentrated on limited numbers of individuals analysed in detail. To allow larger population-based studies, we devised a method for tetramer analysis using 50-100 microlitre blood volumes in a 96-well plate format. We adapted this method to study the effect of age on responses in a cohort of nearly 600 individuals to an immunodominant HLA-A2 restricted response to CMV pp65 (NLVPMVATV). We observed the phenomenon of steady 'memory inflation' with age, similar to recently observed longitudinal data from murine studies. These data show that tetramers can be used as population screening tools and could be used to study age-related, geographical or seasonal effects in a number of other viral infections.

Oxygen-derived free radicals and leukocytes have been implicated in the pathogenesis of ischemia-reperfusion injury. This study aimed at determining, by using biochemical and histochemical techniques, whether an accumulation of neutrophils occurs in the ischemic reperfused rat liver and whether superoxide free radicals play a role in mediating this neutrophil accumulation. Hepatic ischemia was induced by occluding blood supply to the left and median lobes, and reperfusion was reinstituted by releasing the occlusion. Myeloperoxidase activity of the liver was measured with a tetramethylbenzidine-H2O2 assay after removal of glutathione (by dialysis) and in the presence of 3-aminotriazole (catalase inhibitor). A modification of Graham and Karnovsky's method was used to stain neutrophils in liver frozen sections, and the number of neutrophils was counted. Results showed that ischemia-reperfusion of the liver produced a 4.4-fold increase in myeloperoxidase activity (from 0.073 +/- 0.009 to 0.320 +/- 0.017 units/mg liver, means +/- SE), which was proportional to the number of neutrophils (3.1-fold increase from 18 +/- 7 to 57 +/- 4 cells/mm2) in the liver tissue. Pretreatment with long-acting superoxide dismutase significantly attenuated the elevated myeloperoxidase activity and the number of neutrophils. These results indicate that reperfusion after a period of ischemia induces an accumulation of neutrophils in the liver, and superoxide anion free radicals are important mediators in the mechanism of this neutrophil accumulation.

The levels of HBV DNA in tear specimens from young children were high. Tears were confirmed to be infectious, using chimeric mice. Strict precautions should be taken against direct contact with body fluids from HBV carriers with high-level viremia.

ABSTRACT:The role of oxidative stress in the pathogenesis of liver disease in Wilson disease (WD), a genetic disorder characterized by excess hepatic deposition of copper that generates free radicals, remains unclear. This study investigates oxidative stress on the liver and hepatic antioxidant responses in WD using liver specimens from affected patients showing mild liver damage (group I, n ϭ 3), moderate or greater liver damage (group II, n ϭ 5), and fulminant hepatic failure (group III, n ϭ 5) and from asymptomatic carriers (n ϭ 2). Decreased ratios of reduced glutathione (GSH) to oxidized glutathione (GSSG) and increased thiobarbituric acid reactive substance (TBARS), a lipid peroxidation product, were found in every affected patient, especially in group II and III patients. Activities and protein expressions of Mn-dependent superoxide dismutase (Mn-SOD), CuZn-dependent superoxide dismutase (CuZn-SOD), and catalase were decreased in all patients, especially in group III patients. Glutathione peroxidase (GPx) activity was decreased only in group III patients. Asymptomatic carriers without any clinical manifestations showed normal TBARS level and GSH/GSSG ratio with increases in both GSH and GSSG levels. Their CuZn-SOD, Mn-SOD, and catalase activities were increased. These results suggest that excessive copper-derived oxidants contribute to development and progression of liver disease in WD.

All children carrying hepatitis B surface antigen should be observed carefully to monitor the possible development of hepatocellular carcinoma, especially in the antihepatitis B e-positive phase after spontaneous seroconversion or even after interferon treatment.

Although the introduction of hepatitis B vaccine has been contributing to the reduction in the prevalence of hepatitis B virus (HBV) carriers worldwide, the treatment of children with chronic HBV infection is a challenge to be addressed. HBeAg seroconversion, which induces low replication of HBV, is widely accepted as the first goal of antiviral treatment in children with chronic hepatitis B. However, spontaneous HBeAg seroconversion is highly expected in children with chronic HBV infection. Therefore, the identification of children who need antiviral treatment to induce HBeAg seroconversion is essential in the management of chronic HBV infection. Guidelines and experts' opinion show how to identify children who should be treated and how to treat them. If decompensated cirrhosis is absent, interferon-alpha is the first-line antiviral treatment. Nucleos(t)ide analogues (NAs), such as lamivudine, adefovir, entecavir and tenofovir, are also available for the treatment of children, although the approval age differs among them. If decompensated cirrhosis is present, NAs are the first-line antivirals. When the emergence of drug-resistant HBV variants is taken into consideration, entecavir (approved for age 2 years or older) and tenofovir (age 12 years or older), which have high genetic barriers, will play a central role in the treatment of HBV infection. However, the optimal duration of NA treatment and adverse events of long-term NA treatment remain unclear in children. In resource-constrained countries and regions, the financial burden of visiting hospitals, receiving routine blood examination and purchasing antiviral drugs is heavy. Moreover, there is no clear evidence that the induction of HBeAg seroconversion by antiviral treatment prevents the progression of liver disease to cirrhosis and hepatocellular carcinoma in children with chronic HBV infection. It is thus imperative to clarify the clinical impact of antiviral treatment in children with HBV infection.

Although the simplified AIH scoring system has low sensitivity for the diagnosis of AIH in children, the specificity of the simplified AIH scoring system is high. However, the simplified AIH scoring system could not differentiate between AIH and primary sclerosing cholangitis. Therefore, the simplified AIH scoring system does not seem to be a reliable diagnostic tool in children.

Congestive hepatopathy (CH) with chronic passive congestion is characterized by the progression of liver fibrosis without prominent inflammation and hepatocellular damage. Currently, the lack of reliable biomarkers for liver fibrosis in CH often precludes the clinical management of patients with CH. To explore fibrosis biomarkers, we performed proteome analysis on serum exosomes isolated from patients with CH after the Fontan procedure. Exosomal cluster of differentiation (CD)44 levels were increased in patients with CH compared to healthy volunteers and was accompanied by increases in serum levels of soluble CD44 and CD44 expression in the liver. To address the roles of CD44 in CH, we established a mouse model of chronic liver congestion by partial inferior vena cava ligation (pIVCL) that mimics CH by fibrosis progression with less inflammation and cellular damage. In the pIVCL mice, enhanced CD44 expression in hepatic stellate cells (HSCs) and deposition of its ligand hyaluronan were observed in the liver. Blood levels of soluble CD44 were correlated with liver fibrosis. The blockade of CD44 with specific antibody inhibited liver fibrosis in pIVCL mice and was accompanied by a reduction in S100 calcium-binding protein A4 expression following activation of HSCs. Conclusion: Chronic liver congestion promotes fibrosis through CD44. This identifies CD44 as a novel biomarker and therapeutic target of liver fibrosis in patients with CH. (Hepatology Communications 2021;0:1-11).