Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acid sphingomyelinase (ASM) is reported to have an essential function in stress-induced apoptosis although the physiological function of ASM in receptor-triggered apoptosis is unknown. Here, we delineate a pivotal role for ASM in CD95-triggered apoptosis of peripheral lymphocytes or hepatocytes in vivo. We employed intravenous injection of anti-CD4 antibodies or phytohemagglutinin that was previously shown to result in apoptosis of peripheral blood lymphocytes or hepatocytes via the endogenous CD95/CD95 ligand system. Our results demonstrate a high susceptibility in normal mice whereas ASM knock-out mice fail to immunodeplete T cells or develop autoimmune-like hepatitis. Likewise, ASM-deficient mice or hepatocytes and splenocytes ex vivo manifest resistance to anti-CD95 treatment. These results provide in vivo evidence for an important physiological function of ASM in CD95-induced apoptosis.
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PMID:CD95-mediated apoptosis in vivo involves acid sphingomyelinase. 1086 1

A chronic demyelinating disease results from murine infection with the neurotropic strain JHM of mouse hepatitis virus (MHV-JHM). Demyelination is largely immune mediated. In this study, the individual roles of CD4 and CD8 T cells in MHV-induced demyelination were investigated using recombination-activating gene 1-/- (RAG1-/-) mice infected with an attenuated strain of MHV-JHM. These animals develop demyelination only after adoptive transfer of splenocytes from mice previously immunized to MHV. In this study, we show that, following adoptive transfer, virus-specific CD4 and CD8 T cells rapidly infiltrate the CNS of MHV-JHM-infected RAG1-/- mice. Adoptive transfer of CD4 T cell-enriched donors resulted in more severe clinical disease accompanied by less demyelination than was detected in the recipients of undepleted cells. Macrophage infiltration into the gray matter of CD4 T cell-enriched recipients was greater than that observed in mice receiving undepleted splenocytes. In contrast, CD8 T cell-enriched recipients developed delayed disease with extensive demyelination of the spinal cord. MHV-JHM-infected RAG1-/- mice receiving donors depleted of both CD4 and CD8 T cells did not develop demyelination. These results demonstrate that the development of demyelination following MHV infection may be initiated by either CD4 or CD8 T cells. Furthermore, they show that CD4 T cells contribute more prominently than CD8 T cells to the severity of clinical disease, and that this correlates with increased macrophage infiltration into the gray matter.
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PMID:CD4 and CD8 T cells have redundant but not identical roles in virus-induced demyelination. 1092 17

The continued presence of virus-specific CD8(+) T cells within the central nervous system (CNS) following resolution of acute viral encephalomyelitis implicates organ-specific retention. The role of viral persistence in locally maintaining T cells was investigated by infecting mice with either a demyelinating, paralytic (V-1) or nonpathogenic (V-2) variant of a neurotropic mouse hepatitis virus, which differ in the ability to persist within the CNS. Class I tetramer technology revealed more infiltrating virus-specific CD8(+) T cells during acute V-1 compared to V-2 infection. However, both total and virus-specific CD8(+) T cells accumulated at similar peak levels in spinal cords by day 10 postinfection (p.i.). Decreasing viral RNA levels in both brains and spinal cords following initial virus clearance coincided with an overall progressive loss of both total and virus-specific CD8(+) T cells. By 9 weeks p.i., T cells had largely disappeared from brains of both infected groups, consistent with the decline of viral RNA. T cells also completely disappeared from V-2-infected spinal cords coincident with the absence of viral RNA. By contrast, a significant number of CD8(+) T cells which contained detectable viral RNA were recovered from spinal cords of V-1-infected mice. The data indicate that residual virus from a primary CNS infection is a vital component in mediating local retention of both CD8(+) and CD4(+) T cells and that once minimal thresholds of stimuli are lost, T cells within the CNS cannot survive in an autonomous fashion.
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PMID:Role of viral persistence in retaining CD8(+) T cells within the central nervous system. 1093 98

Virus-specific CD4(+) T-cell response at the site of inflammation is believed to play a decisive role for the course of viral disease. In hepatitis C virus (HCV) infection, the majority of studies focused on the peripheral blood T-cell response. In this study we analyzed intrahepatic virus-specific CD4(+) T-cell response and compared this with that in the peripheral blood. Liver and blood-derived T-cell lines were studied in 36 patients (18 with chronic hepatitis C and 18 with HCV-associated cirrhosis). Virus-specific interferon gamma (IFN-gamma) production at a single cell level to various HCV-proteins (core, nonstructural [NS] 3/4, NS5) were determined by enzyme-linked immunospot (ELIspot). Phenotyping was done by fluorescent-activated cell sorter analysis. In approximately half (16 of 36 [44%]) of intrahepatic T-cell lines a significant number of IFN-gamma spots were observed, whereas this was the case in only 19% (7 of 36 T-cell lines) in the blood. In relative terms, core and nonstructural proteins were recognized with the same frequency in both compartments, but HCV-specificity was significantly more often detected in liver tissue compared with the blood. Hepatitis activity index, viral load, and alanine transaminase levels did not correlate with the detection of HCV-specific CD4(+) T cells. All T-cell lines were dominated by CD4(+) T cells. In conclusion, HCV-specific CD4(+) T cells are multispecific, compartmentalize to the liver, and produce IFN-gamma. We speculate that our data would support the concept of compartmentalization of specific T cells at the site of inflammation and that a low frequency of specific T cells is associated with failure to clear the virus and a chronic course of disease.
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PMID:Liver-derived hepatitis C virus (HCV)-specific CD4(+) T cells recognize multiple HCV epitopes and produce interferon gamma. 1096 Apr 55

Exposure to relatively high levels of trichloroethylene has recently been shown to accelerate the development of an autoimmune response in the autoimmune prone MRL+/+ mice. The trichloroethylene-induced autoimmune response was associated with an increase in activated CD4(+) T cells, producing Th(1)-like cytokines. The present study was conducted to determine whether lower, more occupationally relevant doses of trichloroethylene could also promote autoimmunity, in MRL+/+ mice, and if so, to investigate the mechanism of this accelerated autoimmune response. In addition, histological studies were performed to determine if trichloroethylene was capable of producing pathological markers consistent with an autoimmune disease. Trichloroethylene was administered to mice in the drinking water at 0, 0.1, 0.5, and 2.5 mg/ml for 4 and 32 weeks. There was a significant increase above controls in serum antinuclear antibody (ANA) levels following 4 weeks of both 0.1 and 0.5 mg/kg/day of trichloroethylene. After 32 weeks of treatment, ANA levels were elevated and equal in all groups. The kinetics of the ANA response indicated that trichloroethylene accelerated the innate autoimmune response in the MRL+/+ mice. There was a dose-related increase in the percentage of activated CD4(+) T cells in both the spleens and lymph nodes of mice treated for 32 weeks with trichloroethylene when compared to controls. CD4(+) T cells isolated from MRL+/+ mice after either 4 or 32 weeks of treatment with trichloroethylene secreted inflammatory or Th(1)-like cytokines. Following 32 weeks of trichloroethylene treatment, there was a significant increase in hepatic mononuclear infiltration localized to the portal region, a type of hepatic infiltration consistent with autoimmune hepatitis. Taken collectively, these data suggest that exposure to occupationally relevant concentrations of trichloroethylene can accelerate an autoimmune response and can lead to autoimmune disease. The mechanism of this autoimmunity appears to involve, at least in part, activated CD4(+) T cells that then produced inflammatory cytokines.
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PMID:CD4(+) T-cell activation and induction of autoimmune hepatitis following trichloroethylene treatment in MRL+/+ mice. 1100 64

Hepatitic C virus (HCV) viremia is universal after orthotopic liver transplantation (OLT) for HCV cirrhosis. 2. At 5 years post-OLT, approximately 20% of patients have cirrhosis caused by recurrent hepatitis C. 3. Progression of disease is related to immunosuppression, immune response (CD4(+) lymphocytes), HCV genotype, and HCV quasispecies homogeneity. 4. Whether a therapeutic strategy of pre-OLT or early (preemptive) antiviral therapy is better than treating a clinically important hepatitis and the duration of treatment are not known. 5. Monotherapy with recombinant interferon-alpha or ribavirin is not useful in the long term. 6. Combination therapy (interferon and ribavirin) has given better results, but long-term data are not available. 7. HCV recurrence will benefit from randomized studies.
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PMID:Posttransplantation prevention and treatment of recurrent hepatitis C. 1108 83

Treatment of hepatitis B virus carriers with the nucleoside analog lamivudine suppresses virus replication. However, rather than completely eliminating the virus, long-term treatment often ends in the outgrowth of drug-resistant variants. Using woodchucks chronically infected with woodchuck hepatitis virus (WHV), we investigated the consequences of combining lamivudine treatment with immunotherapy mediated by an adenovirus superinfection. Eight infected woodchucks were treated with lamivudine and four were infected with approximately 10(13) particles of an adenovirus type 5 vector expressing beta-galactosidase. Serum samples and liver biopsies collected following the combination therapy revealed a 10- to 20-fold reduction in DNA replication intermediates in three of four woodchucks at 2 weeks after adenovirus infection. At the same time, covalently closed circular DNA (cccDNA) and viral mRNA levels both declined about two- to threefold in those woodchucks, while mRNA levels for gamma interferon and tumor necrosis factor alpha as well as for the T-cell markers CD4 and CD8 were elevated about twofold. Recovery from adenovirus infection was marked by elevation of sorbitol dehydrogenase, a marker for hepatocyte necrosis, as well as an 8- to 10-fold increase in expression of proliferating cell nuclear antigen, a marker for DNA synthesis, indicating significant hepatocyte turnover. The fact that replicative DNA levels declined more than cccDNA and mRNA levels following adenovirus infection suggests that the former decline either was cytokine induced or reflects instability of replicative DNA in regenerating hepatocytes. Virus titers in all four woodchucks were only transiently suppressed, suggesting that the effect of combination therapy is transient and, at least under the conditions used, does not cure chronic WHV infections.
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PMID:Combination therapy with lamivudine and adenovirus causes transient suppression of chronic woodchuck hepatitis virus infections. 1109 Jan 75

The impact of dengue on liver function was studied on fifty serologically confirmed dengue cases admitted to Hospital Universiti Kebangsaan Malaysia (HUKM). Twenty-five of these patients had classic dengue fever (DF) and 25 had grade 1 or 2 dengue hemorrhagic fever (DHF). There were more (60%) DHF patients with hepatomegaly compared to DF (40%) but the difference was not statistically significant. Analysis of the liver profile showed that liver dysfunction was commoner in DHF compared to DF, indicating that the degree of liver impairment may be related to the severity of DHF. Hyperbilirubinemia was noted in 3 (12%) DHF and 2 (8%) DF patients. The mean (range) serum bilirubin was higher in DHF [14.2(5-50) micromol/l] compared to DF [10.9(5-30) micromol/l)] (p > 0.05). Elevated levels of serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were observed more frequently in DHF (20 and 12 patients respectively) compared to DF (16 and 8 patients respectively). Nine (36%) DHF and 6 (24%) DF patients had concomitant elevation of ALT and ALP levels. The mean (range) serum ALT levels were 109.3(23-325) U/l in DHF and 90.8(13-352) U/l in DF (p > 0.05). The mean (range) serum ALP levels were 102.2(15-319) U/l in DHF and 93.3(34-258) U/l in DF (p > 0.05). The ALT and ALP levels were significantly higher in DHF patients with spontaneous bleeding than those without bleeding (p < 0.05) None of the patients developed fulminant hepatitis. The immunoregulatory cells, which include the T (CD3), B (CD 19), CD4, CD8, CD5 and natural killer (NK) cells were significantly lower in DHF compared to DF patients (p < 0.05). However, the reduction in these cell counts did not correlate with the liver dysfunction seen in DHF patients. In conclusion, hepatomegaly and liver dysfunction were commoner in DHF compared to DF.
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PMID:A comparison of the pattern of liver involvement in dengue hemorrhagic fever with classic dengue fever. 1112 22

TNF-alpha has been clearly identified as central mediator of T cell activation-induced acute hepatic injury in mice, e.g., Con A hepatitis. In this model, liver injury depends on both TNFRs, i.e., the 55-kDa TNFR1 as well as the 75-kDa TNFR2. We show in this report that the hepatic TNFRs are not transcriptionally regulated, but are regulated by receptor shedding. TNF directly mediates hepatocellular death by activation of TNFR1 but also induces the expression of inflammatory proteins, such as cytokines and adhesion molecules. Here we provide evidence that resistance of TNFR1(-/-) and TNFR2(-/-) mice against Con A hepatitis is not due to an impaired production of the central mediators TNF and IFN-gamma. Con A injection results in a massive induction of ICAM-1, VCAM-1, and E-selectin in the liver. Lack of either one of both TNFRs did not change adhesion molecule expression in the livers of Con A-treated mice, presumably reflecting the fact that other endothelial cell-activating cytokines up-regulated adhesion molecule expression. However, treatment of TNFR1(-/-) and TNFR2(-/-) mice with murine rTNF revealed a predominant role for TNFR1 for the induction of hepatic adhesion molecule expression. Pretreatment with blocking Abs against E- and P-selectin or of ICAM(-/-) mice with anti-VCAM-1 Abs failed to prevent Con A hepatitis, although accumulation of the critical cell population, i.e., CD4(+) T cells was significantly inhibited. Hence, up-regulation of adhesion molecules during acute hepatitis unlikely contributes to organ injury but rather represents a defense mechanism.
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PMID:TNF-alpha-induced expression of adhesion molecules in the liver is under the control of TNFR1--relevance for concanavalin A-induced hepatitis. 1114 13

Induction of a Th1 immune response against viral infection of the CNS is important in contributing to viral clearance. The present studies demonstrate a role for the T cell chemoattractant chemokine Mig (monokine induced by IFN-gamma) in contributing to a Th1 response against mouse hepatitis virus infection of the CNS. Analysis of the kinetics of Mig expression revealed mRNA transcripts present at days 7 and 12 postinfection (p.i.) but not early (day 2) or late (day 35) in the infection. To determine functional significance, mouse hepatitis virus-infected mice were treated with anti-Mig antisera, and the severity of disease was evaluated. Such treatment resulted in a marked increase in mortality that correlated with a >3 log increase in viral burden within the brains as compared with control mice treated with normal rabbit serum. Anti-Mig-treated mice displayed a significant decrease (p < 0.005) in CD4(+) and CD8(+) T cell recruitment into the CNS as compared with normal rabbit serum-treated mice. In addition, anti-Mig treatment resulted in a significant decrease (p < 0.05) in levels of IFN-gamma and IFN-beta that coincided with increased (p < 0.02) expression of the anti-inflammatory Th2 cytokine IL-10 within the CNS. Collectively, these data indicate that Mig is important in contributing to host defense by promoting a protective Th1 response against viral infection of the CNS.
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PMID:Expression of Mig (monokine induced by interferon-gamma) is important in T lymphocyte recruitment and host defense following viral infection of the central nervous system. 1116 Feb 25


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