Hepatology : official journal of the American Association for the Study of Liver Diseases
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Comparative Study
Hepatitis B virus surface antigen levels: a guide to sustained response to peginterferon alfa-2a in HBeAg-negative chronic hepatitis B.
We investigated the relationship between hepatitis B virus surface antigen (HBsAg) serum level decline and posttreatment response in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B from a large multinational study of pegylated interferon alfa-2a (peginterferon alfa-2a), with or without lamivudine, versus lamivudine alone. Serum HBsAg was quantified using the Architect assay (Abbott Diagnostics) at pretreatment, end of treatment (week 48), and 6 months after the end of treatment (week 72) in sera from 386 of the 537 patients who participated in the multinational study (peginterferon alfa-2a, 127; peginterferon alfa-2a plus lamivudine, 137; lamivudine monotherapy, 122). Pretreatment HBsAg levels varied according to genotype, with the highest levels present in patients infected with genotypes A (median, 4.11 log(10) IU/mL) and D (median, 3.85 log(10) IU/mL). Significant on-treatment decline in HBsAg was observed during treatment with peginterferon alfa-2a (alone or combined with lamivudine; mean decline at week 48, -0.71 and -0.67 log(10) IU/mL, respectively, P < 0.001), but not during treatment with lamivudine alone (-0.02 log(10) IU/mL). Significantly more patients treated with peginterferon alfa-2a (21%) or peginterferon alfa-2a plus lamivudine (17%) achieved HBsAg levels <100 IU/mL at the end of treatment compared with lamivudine (1%) (both P < 0.001 versus lamivudine). End-of-treatment HBsAg level correlated strongly with HBV DNA suppression to
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Natural killer T (NKT) cells and regulatory T cells (Tregs) are both found within the liver and are known to exhibit immune regulatory functions. Hepatic NKT cells are activated early during inflammatory responses and release cytokines, including interferon gamma (IFN-gamma), which we speculated could regulate Treg recruitment to the liver. To examine this, we treated C57BL/6 mice with a specific NKT cell activating ligand alpha galactosyl-C18-ceramide (alphaGal-C18-Cer) and examined the hepatic recruitment of Tregs. We found a time-dependant increase in the hepatic recruitment of Tregs after NKT cell activation, which was absent in NKT cell-deficient mice. Most recruited Tregs expressed interleukin (IL) 10, and to a lesser extent transforming growth factor beta (TGF-beta). Because IFN-gamma induces the production of chemokine (C-X-C motif) ligand 10 (CXCL10), and Tregs can express the cognate receptor for CXCL10 (that is, CXCR3), we considered that CXCL10 might mediate the hepatic recruitment of Tregs after NKT cell activation. Hepatic CXCL10 levels were markedly increased after alphaGal-C18-Cer administration in wild-type but not in NKT cell-deficient mice. Moreover, approximately 50% of Tregs recruited to the liver after alphaGal-C18-Cer administration expressed CXCR3 and CXCR3+ Treg recruitment into the liver was significantly inhibited in IFN-gamma KO mice, and after CXCL10 neutralization. In addition, prevention of CXCR3+ Treg recruitment into the liver enhanced inflammatory effector cell recruitment into the liver after alphaGal-C18-Cer treatment. ⋯ These results show that activated NKT cells can induce the hepatic recruitment of Tregs through a cytokine-to-chemokine pathway, which could be relevant in the development of chemokine blocking or NKT cell activating strategies to treat liver diseases.
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Immune dysregulations in alcoholic liver diseases are still unclear, especially regarding alcoholic hepatitis inflammatory burst. Interleukin-17 (IL-17) is known to enhance neutrophil recruitment. We studied the IL-17 pathway in alcoholic cirrhosis and alcoholic hepatitis. Patients with alcoholic liver disease were compared with patients with chronic hepatitis C virus (HCV) infection or autoimmune liver disease and with healthy controls. IL-17 plasma levels and peripheral blood mononuclear cell secretion were assessed by enzyme-linked immunosorbent assay (ELISA) and T cell phenotype by flow cytometry. IL-17 staining and co-staining with CD3 and myeloperoxidase were performed on liver biopsy specimens. IL-17 receptor expression was studied on liver biopsies and in human hepatic stellate cells as well as their response to recombinant IL-17 by chemotaxis assays. IL-17 plasma levels were dramatically increased in alcoholic liver disease patients. Peripheral blood mononuclear cells of patients with alcoholic liver disease produced higher amounts of IL-17, and their CD4(+) T lymphocytes disclosed an IL-17-secreting phenotype. In the liver, IL-17-secreting cells contributed to inflammatory infiltrates in alcoholic cirrhosis, and alcoholic hepatitis foci disclosed many IL-17(+) cells, including T lymphocytes and neutrophils. In alcoholic liver disease, liver IL-17(+) cells infiltrates correlated to model for end-stage liver disease score, and in alcoholic hepatitis to modified discriminant function. IL-17 receptor was expressed in alcoholic liver disease by hepatic stellate cells, and these cells recruited neutrophils after IL-17 stimulation in a dose-dependent manner through IL-8 and growth related oncogen alpha (GRO-alpha) secretion in vitro. ⋯ Human alcoholic liver disease is characterized by the activation of the IL-17 pathway. In alcoholic hepatitis, liver infiltration with IL-17-secreting cell infiltrates is a key feature that might contribute to liver neutrophil recruitment. (Clinical trials number NCT00610597).
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Activation of c-Jun N-terminal kinase (JNK) has been implicated as a mechanism in the development of steatohepatitis. This finding, together with the reported role of JNK signaling in the development of obesity and insulin resistance, two components of the metabolic syndrome and predisposing factors for fatty liver disease, suggests that JNK may be a central mediator of the metabolic syndrome and an important therapeutic target in steatohepatitis. To define the isoform-specific functions of JNK in steatohepatitis associated with obesity and insulin resistance, the effects of JNK1 or JNK2 ablation were determined in developing and established steatohepatitis induced by a high-fat diet (HFD). HFD-fed jnk1 null mice failed to develop excessive weight gain, insulin resistance, or steatohepatitis. In contrast, jnk2(-/-) mice fed a HFD were obese and insulin-resistant, similar to wild-type mice, and had increased liver injury. In mice with established steatohepatitis, an antisense oligonucleotide knockdown of jnk1 decreased the amount of steatohepatitis in concert with a normalization of insulin sensitivity. Knockdown of jnk2 improved insulin sensitivity but had no effect on hepatic steatosis and markedly increased liver injury. A jnk2 knockdown increased hepatic expression of the proapoptotic Bcl-2 family members Bim and Bax and the increase in liver injury resulted in part from a Bim-dependent activation of the mitochondrial death pathway. ⋯ JNK1 and JNK2 both mediate insulin resistance in HFD-fed mice, but the JNK isoforms have distinct effects on steatohepatitis, with JNK1 promoting steatosis and hepatitis and JNK2 inhibiting hepatocyte cell death by blocking the mitochondrial death pathway.