Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The interaction of non-cythopatic, hepatotropic viruses of hepatitis B and C with the host's immune system plays a critical role in determining the viral clearance and it contributes to the liver damage. The initial line of defence is antigen non-specific and is mediated by natural killer cells and macrophages. Simultaneously, virus-specific immunity is induced by professional antigen presenting cells that process and present viral antigens to T and B lymphocytes in the regional lymph nodes. Thereafter, viral specific T helper cells are activated and these cells initiate the anti-viral immune responses of B and CTL lymphocytes. Early, multispecific T cell responses are associated with viral clearance, whereas the imbalance of viral specific Th1 and Th2 lymphocytes plays a crucial role in the viral persistence. The imbalance of viral specific Th1 and Th2 lymphocytes leads to inadequate activation of antigen specific CTL cells. After recognition of viral antigens, T helper lymphocytes are differentiated to Th1 and Th2 cells according to the type of secreted cytokines. Th1 cells produce cytokines: interleukin-2, IFN-gamma, TNF-alpha, which are responsible for effective activation of CTL cells. In contrast, interleukin-4, interleukin-5 and interleukin-10 are secreted by Th2 cells, which are involved in activation of B lymphocytes and in production of neutralizing antibodies. These finding suggests that the viral clearance is associated with the early development and adequate mounting of the anti-viral multispecific immune responses of T helper and cytotoxic T lymphocytes.
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PMID:[New views on immunopathology of viral hepatitis B and C]. 1463 21

Background: Experimental studies demonstrate that hepatitis B virus may induce nitric oxide (NO) production in infected hepatocytes. Its presence in acute hepatitis B patients has not been studied. Methods: Serum levels of nitric oxide and its regulatory pro-inflammatory cytokines were detected in 15 patients with uncomplicated acute hepatitis B, 19 blood donors and 15 chronic hepatitis B patients. Cytokines were determined with an immunoassay. Nitric oxide was measured as the serum metabolic products of nitrates and nitrites using a modification of the Griess reaction. Results: All detected cytokines were increased in acute hepatitis B patients compared to healthy controls (p<0.001 for TNF-alpha, p<0.05 for IL-6, p<0.001 for IL1-beta and p<0.001 for IFN-gamma). High serum levels of nitric oxide were found in acute hepatitis B patients (156.96+/-9.76 micromol/l) compared to healthy controls (51+/-6.2 micromol/l, p<0.001) and chronic hepatitis B patients (63.97+/-3.78 micromol/l, p<0.001). No significant correlations were found between NO, cytokine levels and transaminases. Conclusions: High levels of nitric oxide and its regulatory cytokines were found in a group of patients with uncomplicated acute hepatitis B. The exact role of NO in the disease pathogenesis and outcome needs to be studied further.
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PMID:Nitric oxide and pro-inflammatory cytokines in acute hepatitis B. 1506 46

The mechanisms that determine viral clearance or viral persistence in chronic viral hepatitis have yet to be identified. Recent advances in molecular genetics have permitted the detection of variations in immune response, often associated with polymorphism in the human genome. Differences in host susceptibility to infectious disease and disease severity cannot be attributed solely to the virulence of microbial agents. Several recent advances concerning the influence of human genes in chronic viral hepatitis B and C are discussed in this article: a) the associations between human leukocyte antigen polymorphism and viral hepatic disease susceptibility or resistance; b) protective alleles influencing hepatitis B virus (HBV) and hepatitis C virus (HCV) evolution; c) prejudicial alleles influencing HBV and HCV; d) candidate genes associated with HBV and HCV evolution; d) other genetic factors that may contribute to chronic hepatitis C evolution (genes influencing hepatic stellate cells, TGF-beta 1 and TNF-alpha production, hepatic iron deposits and angiotensin II production, among others). Recent discoveries regarding genetic associations with chronic viral hepatitis may provide clues to understanding the development of end-stage complications such as cirrhosis or hepatocellular carcinoma. In the near future, analysis of the human genome will allow the elucidation of both the natural course of viral hepatitis and its response to therapy.
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PMID:The influence of the human genome on chronic viral hepatitis outcome. 1528 11

Background: Rebound hepatitis is a potentially life-threatening complication of withdrawal from immunosuppressive therapy in patients with chronic Hepatitis B viral (HBV) infections. Objectives: To document the incidence of rebound hepatitis and determine whether the hepatitis is associated with serologic evidence of immunological rebound or the appearance of specific mutations in the HBV genome. Methods: Serum cytokines (IL-6, IL-10, TNF-alpha and INF-gamma) were documented by enzyme linked immunoassays and previously described HBV mutants (surface, core, pre-core and basal core promoter) by signal probe hybridization analysis in chronic HBV carriers treated with either 6 weeks of prednisone followed by 6 weeks of acyclovir (PR/AC, n = 20) or placebo/placebo (PL/PL, n = 20). Results: Rebound hepatitis (serum ALT > 2X baseline) occurred in 6/20 (30%) PR/AC patients versus 2/20 (10%) PL/PL recipients (P = 0.24). Serum cytokine levels were similar in those who developed rebound hepatitis compared to those who did not. HBV mutants were absent prior to and during treatment but developed in the follow-up period in three patients. All three patients were PR/AC recipients and in each case, the HBV mutation was in the basal core promoter gene. In two of the three patients, the mutant appeared just prior to the onset of rebound hepatitis while in the third, rebound hepatitis did not occur. Conclusions: The results of this study indicate an association exists between some cases of rebound hepatitis and the development of HBV mutants.
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PMID:Rebound hepatitis following withdrawal of immunosuppressive therapy in patients with chronic Hepatitis B viral infections. 1534 68

Activation of the cellular stress pathways (c-Jun N-terminal kinase [JNK] and p38 mitogen-activated protein [MAP] kinase) is linked to apoptosis. However, whether both pathways are required for apoptosis remains unresolved. Hepatitis B virus X protein (pX) activates p38 MAP kinase and JNK pathways and, in response to weak apoptotic signals, sensitizes hepatocytes to apoptosis. Employing hepatocyte cell lines expressing pX, which was regulated by tetracycline, we investigated the mechanism of apoptosis by p38 MAP kinase and JNK pathway activation. Inhibition of the p38 MAP kinase pathway rescues by 80% the initiation of pX-mediated apoptosis, whereas subsequent apoptotic events involve both pathways. pX-mediated activation of p38 MAP kinase and JNK pathways is sustained, inducing the transcription of the death receptor family genes encoding Fas/FasL and tumor necrosis factor receptor 1 (TNFR1)/TNF-alpha and the p53-regulated Bax and Noxa genes. The pX-dependent expression of Fas/FasL and TNFR1/TNF-alpha mediates caspase 8 activation, resulting in Bid cleavage. In turn, activated Bid, acting with pX-induced Bax and Noxa, mediates the mitochondrial release of cytochrome c, resulting in the activation of caspase 9 and apoptosis. Combined antibody neutralization of FasL and TNF-alpha reduces by 70% the initiation of pX-mediated apoptosis. These results support the importance of the pX-dependent activation of both the p38 MAP kinase and JNK pathways in pX-mediated apoptosis and suggest that this mechanism of apoptosis occurs in vivo in response to weak apoptotic signals.
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PMID:Sustained activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase pathways by hepatitis B virus X protein mediates apoptosis via induction of Fas/FasL and tumor necrosis factor (TNF) receptor 1/TNF-alpha expression. 1554 43

Glossogyne tenuifolia (Hsiang-Ju) is a traditional antipyretic and hepatoprotective herb used in Chinese medicine. The aim of this research is to investigate the pharmacological activities and potent components of the ethanol extract of Glossogyne tenuifolia (GT) in human primary cells and cell line. We found that GT (0.1 approximately 0.25 mg/ml) exerted dose-dependent inhibitions on the release of TNF-alpha and IL-6 in LPS-activated human whole blood and peripheral blood mononuclear cells (PBMC), and IFN-gamma in PHA-stimulated human whole blood. The lack of cytotoxicity indicated that the inhibitory effects of GT on cytokine production were not due to cell death. Luteolin, the deglycosylated derivative of one of the major compositions, luteolin-7-glucoside, exerted inhibitory effects on TNF-alpha, IL-6 and IFN-gamma production in activated human whole blood with estimated IC(50)s of 42.73 microM, 44.86 microM and 3.34 microM, respectively. Furthermore, GT had potent anti-hepatitis B virus (HBV) effects on the human hepatocellular carcinoma cell line, PLC/PRF/5. GT exhibited a dose-dependent inhibition on the release of hepatitis B surface antigen (HBsAg) by repressing the expression of HBsAg with IC(50) of 0.093 mg/ml. We concluded that GT exerted combinatorial anti-inflammatory and antiviral effects, and the multiple actions may underlie its traditional hepatoprotective function.
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PMID:Anti-inflammatory and antiviral effects of Glossogyne tenuifolia. 1562 May 77

A PCR restriction fragment length polymorphism assay was used to analyse single-nucleotide polymorphisms in the tumour necrosis factor (TNF)-alpha and TNF-beta genes of 56 patients with chronic severe hepatitis B virus (HBV) infection, 71 patients who either had chronic mild HBV infection or who were asymptomatic carriers, and 90 healthy controls. The serum TNF-alpha concentrations in patients with chronic severe HBV infection were compared to those of 30 healthy controls by radioimmunoassay. The frequencies of the TNF1/2 genotype and the TNF2 allele were greater in patients with chronic severe HBV infection than in healthy controls (25% vs. 11.1%, p 0.015; 12.5% vs. 5.6%, p 0.036, respectively) and patients with chronic mild HBV infection and asymptomatic carriers (25% vs. 8.8%, p 0.011; 12.5% vs. 4.2%, p 0.015, respectively). Heterozygotes carrying the TNF2 allele had higher levels of serum TNF-alpha than homozygotes for the wild-type allele among all patients with chronic severe HBV infection (p <0.01). The genotype distribution and allele frequency of TNF-beta were similar for patients with chronic severe HBV infection and healthy controls, but the frequency of the TNF-beta*2/2 genotype in patients with chronic mild HBV infection and asymptomatic controls was lower than for healthy controls (9.9% vs. 22.4%, p 0.043) or patients with chronic severe HBV infection (9.9% vs. 26.8%, p 0.043), although this was not significant after correction for multiple testing. It was concluded that TNF-alpha gene polymorphisms may play an important role as a host factor in the progression of HBV infection.
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PMID:Association between tumour necrosis factor gene polymorphisms and the clinical types of patients with chronic hepatitis B virus infection. 1564 4

COX-2 specific anti-inflammatory agents appear as able to induce a flare of inflammatory bowel disease as classical anti-inflammatory agents. The use of steroids, immunomodulators or infliximab prior to surgery does not appear to increase post-operative complication rates. Cases of hepatitis B reactivation have been described after infliximab therapy, suggesting that hepatitis B serological status should be verified prior to infliximab therapy. Adalimubab, a fully humanized antibody directed against TNF-alpha, is efficacious in patients that have lost response or did not tolerate infliximab. Approval of this agent is still awaited. Leucoapheresis is a promising tool in ulcerative colitis.
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PMID:[Inflammatory bowel diseases]. 1577 Aug 16

The hepatitis B virus (HBV) core Ag (HBcAg) serves as the structural subunit of the highly immunogenic capsid shell. HBcAg harbors a unique arginine-rich C terminus that was implicated in immune responses induced by the capsid. In this study, we examined the capacity of the HBV capsid to induce proinflammatory and regulatory cytokines in human THP-1 macrophages and the possible underlying mechanism. Full-length HBc capsids, but not HBc-144 capsids lacking the arginine-rich domain of HBcAg, efficiently bound differentiated THP-1 macrophages and strongly induced TNF-alpha, IL-6, and IL-12p40. Capsid binding to macrophages and cytokine induction were independent of the RNA associated with the arginine-rich domain. Soluble heparin and heparan sulfate but not chondroitin sulfates greatly diminished cytokine induction through inhibition of capsid binding to THP-1 macrophages. Furthermore, serine phosphorylation in the arginine-rich domain modulates capsid binding to macrophages and the cytokine response. Induction of cytokines by the capsid involved activation of NF-kappaB, ERK-1/2, and p38 MAPK and did not require endosomal acidification. Finally, NF-kappaB activation by the capsid in HEK 293 cells specifically required expression of TLR2 and was compromised by soluble heparin. Thus, cytokine induction by the HBV capsid in macrophages is facilitated by interaction of its arginine-rich domain with membrane heparan sulfate and involves signaling through TLR2.
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PMID:Cytokine induction by the hepatitis B virus capsid in macrophages is facilitated by membrane heparan sulfate and involves TLR2. 1627 74

It is well-documented that alcohol drinking together with hepatitis viral infection accelerates liver injury; however the underlying mechanisms remain unknown. In this paper, we demonstrated that primary hepatocytes from transgenic mice overexpressing hepatitis B virus X protein (HBX) were more susceptible to ethanol- and TNF-alpha-induced apoptotic killing. Compared to normal control mouse hepatocytes, ethanol and/or TNF-alpha treatment led to a significant increase in reactive oxygen species, mitochondrial permeability transition, cytochrome C release, caspase-3 activity, and poly (ADP-ribose) polymerase degradation in hepatocytes from HBX transgenic mice. Blocking caspase-3 activity antagonized ethanol- and TNF-alpha-induced apoptosis in primary hepatocytes from HBX transgenic mice. Taken together, our findings suggest that HBX sensitizes primary mouse hepatocytes to ethanol- and TNF-alpha-induced apoptosis by a caspase-3-dependent mechanism, which may partly explain the synergistic effects of alcohol consumption and hepatitis B virus infection on liver injury.
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PMID:Hepatitis B virus X protein sensitizes primary mouse hepatocytes to ethanol- and TNF-alpha-induced apoptosis by a caspase-3-dependent mechanism. 1621 10


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