Tumour necrosis factor production in fulminant hepatic failure: relation to aetiology and superimposed microbial infection

Microcirculatory disturbance in acute liver injury is triggered by IFNγ-CD40 axis

BACKGROUND

Acute liver failure (ALF) is a life-threatening disorder that progresses from self-limiting acute liver injury (ALI). Microcirculatory disturbance characterized by sinusoidal hypercoagulation and subsequent massive hypoxic hepatocyte damage have been proposed to be the mechanism by which ALI deteriorates to ALF; however, the precise molecular pathway of the sinusoidal hypercoagulation remains unknown. Here, we analyzed ALI patients and mice models to uncover the pathogenesis of ALI with microcirculatory disturbance.

METHODS

We conducted a single-center retrospective study for ALI and blood samples and liver tissues were analyzed to evaluate the microcirculatory disturbance in ALI patients (n = 120). Single-cell RNA sequencing analysis (scRNA-seq) was applied to the liver from the concanavalin A (Con A)‑induced mouse model of ALI. Interferon-gamma (IFNγ) and tumor necrosis factor-alpha knockout mice, and primary human liver sinusoidal endothelial cells (LSECs) were used to assess the mechanism of microcirculatory disturbance.

RESULTS

The serum IFNγ concentrations were significantly higher in ALI patients with microcirculatory disturbance than in patients without microcirculatory disturbance, and the IFNγ was upregulated in the Con A mouse model which presented microcirculatory disturbance. Hepatic IFNγ expression was increased as early as 1 hour after Con A treatment prior to sinusoidal hypercoagulation and hypoxic liver damage. scRNA-seq revealed that IFNγ was upregulated in innate lymphoid cells and stimulated hepatic vascular endothelial cells at the early stage of liver injury. In IFNγ knockout mice treated with Con A, the sinusoidal hypercoagulation and liver damage were remarkably attenuated, concomitant with the complete inhibition of CD40 and tissue factor (TF) upregulation in vascular endothelial cells. By ligand-receptor analysis, CD40-CD40 ligand interaction was identified in vascular endothelial cells. In human LSECs, IFNγ upregulated CD40 expression and TF was further induced by increased CD40-CD40 ligand interaction. Consistent with these findings, hepatic CD40 expression was significantly elevated in human ALI patients with microcirculatory disturbance.

CONCLUSION

We identified the critical role of the IFNγ-CD40 axis as the molecular mechanism of microcirculatory disturbance in ALI. This finding may provide novel insights into the pathogenesis of ALI and potentially contribute to the emergence of new therapeutic strategies for ALI patients.

Cirrhosis and Trauma: A Deadly Duo

It has been previously reported that trauma patients with cirrhosis undergoing emergency abdominal operations exhibit a fourfold increase in mortality independent of their Child's classification. We undertook this review to assess the impact of cirrhosis on trauma patients. We reviewed the records of patients from 1993 to 2003 with documented hepatic cirrhosis and compared them to a 2:1 control population without hepatic cirrhosis and matched for age, sex, Injury Severity Score (ISS), and Glasgow Coma Score (GCS). Demographic, severity of injury, and outcome data were recorded. Student's t test and χ2 were used for statistical analysis and a P < 0.05 was significant. Sixty-one patients had documented cirrhosis and were compared to 156 matched controls. Comparing the two groups demonstrates there was no difference in age, ISS, or GCS. Intensive care stay, hospital length of stay, blood requirements in the first 24 hours postinjury, and mortality (33% vs 1%) was significantly greater in the trauma patients with cirrhosis. Fifty-five per cent of deaths in the cirrhosis group was due to sepsis, and, as the Child's class increases, so does the mortality (Child's A, 15%; B, 37%; and C, 63%). In 64 per cent of cirrhotics without an emergent abdominal operation, mortality was 21 per cent. In the 36 per cent of cirrhotics who had emergent abdominal operation, mortality was 55 per cent. Hepatic cirrhosis in trauma patients, regardless of severity of injury or the need for an abdominal intervention, is a poor prognostic indicator. The necessity of an abdominal operative intervention further amplifies this effect. Trauma and cirrhosis is, in fact, a deadly duo.

The use of aliskiren as an antifibrotic drug in experimental models: A systematic review

Aliskiren is an oral antihypertensive medication that acts by directly inhibiting renin. High levels of circulating renin and prorenin activate the pathological signaling pathway of fibrosis. This drug also reduces oxidative stress. Thus, the aim of this systematic review is to analyze experimental studies that show the actions of aliskiren on fibrosis. PubMed and LILACS databases were consulted using the keywords aliskiren and fibrosis within the period between 2005 and 2017. Fifty-three articles were analyzed. In the heart, aliskiren attenuated remodeling, hypertrophy, inflammatory cytokines, collagen deposition, and oxidative stress. In the kidneys, there was a reduction in interstitial fibrosis, the infiltration of inflammatory cells, apoptosis, proteinuria, and in the recruitment of macrophages. In diabetic models, an improvement in the albumin/creatinine relationship and in the insulin pathway in skeletal muscles was observed; aliskiren was beneficial to pancreatic function and glucose tolerance. In the liver, aliskiren reduced fibrosis, steatosis, inflammatory cytokines, and collagen deposition. In the lung and peritoneal tissues, there was a reduction in fibrosis. Many studies have reported on the beneficial effects of aliskiren on endothelial function and arterial rigidity. A reduction in fibrosis in different organs is cited by many authors, which complies with the results found in this review. However, studies diverge on the use of the drug in diabetic patients. Aliskiren has antifibrotic potential in several experimental models, interfering with the levels of fibrogenic cytokines and oxidative stress. Therefore, its use in diseases in which fibrosis plays an important pathophysiological role is suggested.

Receptor-Interacting Protein Kinase 3 (RIPK3) mRNA Levels Are Elevated in Blood Mononuclear Cells of Patients with Poor Prognosis of Acute-on-Chronic Hepatitis B Liver Failure

Necroptosis refers to a programmed form of necrosis, which involves the receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like protein (MLKL). In this study, to investigate the role of necroptosis in the pathogenesis of acute-on-chronic hepatitis B liver failure (ACHBLF), we retrospectively analyzed 122 patients with ACHBLF, 131 patients with chronic hepatitis B (CHB), and 35 healthy controls (HCs). Using quantitative real-time polymerase chain reaction (RT-qPCR), we measured RIPK3 mRNA levels in peripheral blood mononuclear cells (PBMCs). ELISA was performed to measure the serum levels of MLKL, TNF-α and caspase-8. We found that RIPK3 mRNA levels were significantly higher in patients with ACHBLF than those with CHB or HCs. RIPK3 mRNA levels in patients with ACHBLF were positively correlated with serum levels of TNF-α or MLKL and negatively correlated with caspase-8 levels. Univariate and multivariate analysis revealed that RIPK3 mRNA level was predictive of 3-month mortality of ACHBLF. The area under receiver operating characteristic curve (AUC) of RIPK3 mRNA levels was 0.810 (95% CI: 0.729-0.876), which was higher than that of MELD scores (0.766, 95% CI: 0.681-0.838). The optimal cut-off point of 8.81 was determined for RIPK3 mRNA levels, which showed a sensitivity of 80.7% and a negative predictive value of 80.4%. These results indicate that elevated RIPK3 mRNA levels in PBMCs are associated with poor prognosis of ACHBLF. We thus propose that necroptosis may play an important role in pathogenesis of ACHBLF.

Toll-like receptor-2 exacerbates murine acute viral hepatitis

Viral replication in the liver is generally detected by cellular endosomal Toll‐like receptors (TLRs) and cytosolic helicase sensors that trigger antiviral inflammatory responses. Recent evidence suggests that surface TLR2 may also contribute to viral detection through recognition of viral coat proteins but its role in the outcome of acute viral infection remains elusive. In this study, we examined in vivo the role of TLR2 in acute infections induced by the highly hepatotrophic mouse hepatitis virus (MHV) type 3 and weakly hepatotrophic MHV‐A59 serotype. To address this, C57BL/6 (wild‐type; WT) and TLR2 knockout (KO) groups of mice were intraperitoneally infected with MHV3 or MHV‐A59. MHV3 infection provoked a fulminant hepatitis in WT mice, characterized by early mortality and high alanine and aspartate transaminase levels, histopathological lesions and viral replication whereas infection of TLR2 KO mice was markedly less severe. MHV‐A59 provoked a comparable mild and subclinical hepatitis in WT and TLR2 KO mice. MHV3‐induced fulminant hepatitis in WT mice correlated with higher hepatic expression of interferon‐β, interleukin‐6, tumour necrosis factor‐α, CXCL1, CCL2, CXCL10 and alarmin (interleukin‐33) than in MHV‐A59‐infected WT mice and in MHV3‐infected TLR2 KO mice. Intrahepatic recruited neutrophils, natural killer cells, natural killer T cells or macrophages rapidly decreased in MHV3‐infected WT mice whereas they were sustained in MHV‐A59‐infected WT mice and MHV3‐infected TLR2 KO. MHV3 in vitro infection of macrophagic cells induced rapid and higher viral replication and/or interleukin‐6 induction in comparison to MHV‐A59, and depended on viral activation of TLR2 and p38 mitogen‐activated protein kinase. Taken together, these results support a new aggravating inflammatory role for TLR2 in MHV3‐induced acute fulminant hepatitis.

Prognostic significance of infections in critically ill adult patients with acute liver injury: a retrospective cohort study

BACKGROUND AND AIMS

Patients with acute liver failure have high rates of infections, likely from defects in immune function. Whether infections are independently associated with poor outcomes is unclear. We hypothesized that patients with acute liver injury who developed infections were at increased risk of adverse outcomes.

METHODS

We conducted a retrospective analysis of 150 critically ill adult patients admitted with acute liver dysfunction at a single academic institution between 2005 and 2011. We excluded patients with immunocompromised states, patients with chronic liver disease and patients who died or were discharged within 48 h of admission. Our primary endpoint was a 30-day event-free survival, with events defined as either death or liver transplantation. Our secondary endpoint was length of stay. Univariate and multivariate analyses were performed to determine associations between presence of infection and our primary and secondary endpoints.

RESULTS

Of our cohort of 150 patients, 62 (41%) were infected and 88 (59%) were not infected. Of the infected patients, 45% died or underwent transplantation, compared to 22% for the non-infected patients (P = 0.003). Univariate and multivariate analyses demonstrated that infections in patients with acute liver dysfunction were an independent predictor of poor outcome (i.e. death or transplantation). In addition, specific types of infection, including pneumonia, independently led to a 48% increase in length of stay (P = 0.002).

CONCLUSIONS

Infections in patients with acute liver dysfunction are associated with increased risk of death or transplant and increased hospital length of stay.

Promoter methylation status and expression of PPAR-γ gene are associated with prognosis of acute-on-chronic hepatitis B liver failure

Background

Peroxisome proliferator-activated receptor gamma (PPAR-γ) has been demonstrated to be involved in anti-inflammatory reactions, but its role in acute-on-chronic hepatitis B liver failure (ACHBLF) is unclear. Therefore, DNA methylation patterns and expression level of PPAR-γ gene were detected in peripheral blood mononuclear cells (PBMCs) from 81 patients with ACHBLF, 50 patients with chronic hepatitis B (CHB), and 30 healthy controls, and the possible role of PPAR-γ in ACHBLF was analyzed.

Results

We found that aberrant PPAR-γ promoter methylation was attenuated in ACHBLF patients compared with CHB patients and was responsible for the elevated PPAR-γ expression level, which was negatively correlated with total bilirubin and international normalized ratio. Plasma level of TNF-α and IL-6 in ACHBLF patients were higher than CHB patients and healthy controls and significantly reduced in unmethylated group. ACHBLF patients with PPAR-γ promoter methylation had poorer outcomes than those without. Correspondingly, PPAR-γ messenger RNA (mRNA) level was higher in survivors than non-survivors and gradually increased in survivors with time, while remained low level in non-survivors.

Conclusions

Aberrant promoter methylation decline and PPAR-γ expression rebound occurred in ACHBLF compared with CHB and could improve prognosis of ACHBLF by negatively regulating cytokines.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0149-2) contains supplementary material, which is available to authorized users.

Serum tumor necrosis factor-alpha level in hepatitis E virus-related acute viral hepatitis and fulminant hepatic failure in pregnant women

AIM

The host response in hepatitis E virus (HEV)-related liver disease of pregnant women is unclear. This study was carried out to evaluate the serum concentration of tumor necrosis factor (TNF)-α in HEV-related acute viral hepatitis (AVH) and fulminant hepatic failure (FHF) in pregnant women in relation to pregnancy outcome.

METHODS

The study included 262 pregnant and 158 non-pregnant women with jaundice. There were 160 healthy asymptomatic pregnant women and 124 healthy asymptomatic non-pregnant women as controls. The jaundiced patients were classified as AVH or FHF. Serum TNF-α level was assayed by commercially available enzyme-linked immunoassay kits.

RESULTS

A significantly higher level of TNF-α was observed in HEV-infected pregnant women than non-HEV pregnant women (P < 0.001). TNF-α level was significantly higher in AVH and FHF of HEV-infected pregnant women compared with AVH and FHF of HEV infected non-pregnant women (P = 0.036 and P = 0.010, respectively). The HEV-infected pregnant FHF expired group had significantly higher levels of TNF-α than the non-pregnant FHF expired group (P = 0.025). TNF-α levels were significantly higher in AVH of HEV-infected pregnant women than healthy pregnant controls (P < 0.001). Higher TNF-α levels were observed in HEV-infected women having preterm delivery and low birthweight newborns compared with non-HEV and healthy pregnant women.

CONCLUSION

Higher serum concentration of TNF-α observed in HEV infected AVH and FHF pregnant cases shows that pregnancy with HEV infection increases TNF-α secretion. TNF-α may be an important factor in the outcomes of pregnancy due to HEV infection.

Functional role of monocytes and macrophages for the inflammatory response in acute liver injury

Different etiologies such as drug toxicity, acute viral hepatitis B, or acetaminophen poisoning can cause acute liver injury or even acute liver failure (ALF). Excessive cell death of hepatocytes in the liver is known to result in a strong hepatic inflammation. Experimental murine models of liver injury highlighted the importance of hepatic macrophages, so-called Kupffer cells, for initiating and driving this inflammatory response by releasing proinflammatory cytokines and chemokines including tumor necrosis factor (TNF), interleukin-6 (IL-6), IL-1beta, or monocyte-chemoattractant protein-1 (MCP-1, CCL2) as well as activating other non-parenchymal liver cells, e.g., endothelial or hepatic stellate cells. Many of these proinflammatory mediators can trigger hepatocytic cell death pathways, e.g., via caspase activation, but also activate protective signaling pathways, e.g., via nuclear factor kappa B (NF-κB). Recent studies in mice demonstrated that these macrophage actions largely depend on the recruitment of monocytes into the liver, namely of the inflammatory Ly6c+ (Gr1+) monocyte subset as precursors of tissue macrophages. The chemokine receptor CCR2 and its ligand MCP-1/CCL2 promote monocyte subset infiltration upon liver injury. In contrast, the chemokine receptor CX3CR1 and its ligand fractalkine (CX3CL1) are important negative regulators of monocyte infiltration by controlling their survival and differentiation into functionally diverse macrophage subsets upon injury. The recently identified cellular and molecular pathways for monocyte subset recruitment, macrophage differentiation, and interactions with other hepatic cell types in the injured liver may therefore represent interesting novel targets for future therapeutic approaches in ALF.

Protective effects of Asiaticoside on acute liver injury induced by lipopolysaccharide/D-galactosamine in mice

Asiaticoside (AS), a triterpenoid product isolated from Centella asiatica, has been described to exhibit anti-in fl ammatory activities in several inflammatory models. However, the effects of AS on liver injury are poorly understood. The present study was undertaken to investigate whether AS is efficacious against Lipopolysaccharide (LPS) /D-galactosamine (D-GalN)-induced acute liver injury in mice and its potential mechanisms. AS (5, 10 and 20 mg/kg/d) was pretreated orally once daily for 3 days before LPS/D-GalN injected in mice. The mortality, hepatic tissue histology, plasma levels of Tumor necrosis factor-alpha (TNF-alpha) and alanine aminotransferase (ALT) and aspartate aminotransferase (AST), hepatic tissue TNF-alpha and caspase-3 activity were measured. Besides, western blotting analysis of phospho-p38 mitogen-activated protein kinase (phospho-p38 MAPK), phospho-c-jun N-terminal kinase (phospho-JNK) and phospho-extracellular signal regulated kinase (phospho-ERK) were determined. As a result, AS showed significant protection as evidenced by the decrease of elevated aminotransferases, hepatocytes apoptosis and caspase-3, alleviation of mortality and improvement of liver pathological injury in a dose-dependent manner. Further, we found that AS dose-dependently reduced the elevation of phospho-p38 MAPK, phospho-JNK, phospho-ERK protein and TNF-alpha mRNA expression in liver tissues and plasma TNF-alpha. These results suggest that AS has remarkable hepatoprotective effects on LPS/D-GalN-induced liver injury and the possible mechanism is related to inhibition of TNF-alpha and MAPKs.

Association of tumor necrosis factor-alpha gene promoter polymorphisms with acute viral hepatitis in the Indian population

The key elements that determine the host response to either the self-limited or a severe fulminant form of liver disease are unclear. We have investigated the potential association of single nucleotide polymorphisms (SNPs) in the promoter region of tumor necrosis factor-alpha (TNFalpha) in their susceptibility to acute viral hepatitis (AVH) and fulminant hepatic failure (FHF) patients exhibiting specific viral etiology. A total of 124 individuals including 64 cases comprising 27 FHF, 37 AVH, and 60 healthy controls were recruited. SNPs at -238 (G/A), -308 (G/A), -857 (C/T), and -863 (C/A) of TNFalpha were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and confirmed by direct sequencing. Serum levels of TNFalpha were determined at admission and death or recovery. Association between the TNFalpha genotype and susceptibility to FHF was not evident; however, carrier genotypes in relation to the -308 (GA/AA) and -857 (CT/TT) loci were found to be significantly (P < or = 0.05) associated with susceptibility to AVH in relation to controls. The mean TNFalpha serum levels at admission were significantly higher (P < 0.001) in FHF than AVH patients, but no marked difference was observed between FHF-E (expired; n = 17) and FHF-S (survivors; n = 10), though the former were comparatively higher. This study suggests that SNPs at -308 and -857 of the TNFalpha promoter may represent an increased risk for the development of AVH but not for FHF in the Indian population.

Tumour necrosis factor-alpha and soluble Fas ligand as biomarkers in non-acetaminophen-induced acute liver failure

OBJECTIVES

Cytokines as prognostic markers in acute liver failure (ALF) have not been evaluated in the Indian subcontinent with hepatitis E as the commonest aetiological agent. We investigated the clinical significance of proinflammatory/apoptotic cytokines soluble Fas ligand (sFasL) and tumour necrosis factor (TNF)-alpha in ALF of specific aetiology.

METHODS

A total of 82 cases, 37 ALF and 45 acute hepatitis (AH), and 60 healthy controls were recruited. Serum levels of sFasL and TNF-alpha were determined at admission and death/recovery.

RESULTS

Mean sFasL and TNF-alpha serum levels at admission were significantly higher (p < 0.001) in patients with ALF than AH, but no marked difference was observed between ALF-E (expired, n = 23) and ALF-S (survivors, n = 14), although the former had comparatively higher levels. ALF-E had higher than baseline TNF-alpha and sFasL concentrations at death, while in the ALF-S group the samples obtained from the patients as soon as they came out of encephalopathy, showed either lower or similar TNF-alpha and sFasL levels as found at admission.

CONCLUSION

The high levels of sFasL and TNF-alpha are associated with ALF. Following the trend of these cytokines can be useful in predicting death and timely referral to a transplant centre.

The importance of immune dysfunction in determining outcome in acute liver failure

Acute liver failure (ALF) shares striking similarities with septic shock with regard to the features of systemic inflammation, progression to multiple organ dysfunction and functional immunoparesis. While the existence of opposing systemic pro- and anti-inflammatory profiles resulting in organ failure and immune dysfunction are well recognised in septic shock, characterization of these processes in ALF has only recently been described. This review explores the evolution of the systemic inflammation in acute liver failure, its relation to disease progression, exacerbation of liver injury and development of innate immune dysfunction and extra-hepatic organ failure as sequelae. Defects in innate immunity are described in hepatic and extra-hepatic compartments. Clinical studies measuring levels of pro- and anti-inflammatory cytokines and expression of the antigen presentation molecule HLA-DR on monocytes, in combination with ex-vivo experiments, demonstrate that the persistence of a compensatory anti-inflammatory response syndrome, leading to functional monocyte deactivation, is a central event in the evolution of systemic immune dysfunction. Accurate immune profiling in ALF may permit the development of immunomodulatory strategies in order to improve outcome in this condition.

Selective suppression of NF-kBp65 in hepatitis virus-infected pregnant women manifesting severe liver damage and high mortality

Fulminant hepatitis in Asian pregnant women is generally caused by hepatitis E virus infection, and extremely high mortality is most common in them. Decreased cell-mediated immunity is considered a major cause of death in these cases, but what exactly influences decreased immunity and high mortality specifically during pregnancy is not known. We used electrophoretic mobility shift assays, immunoblotting, and immunohistochemical analysis to study the expression and DNA binding activity of NF-kB p50 and NF-kB p65 in pregnant fulminant hepatic failure (FHF) patients and compared them with their nonpregnant counterparts. In both PBMC and postmortem liver biopsy specimens the DNA-binding activity of NF-kB was very high in samples from pregnant FHF patients compared with those from nonpregnant women as well as pregnant women with acute viral hepatitis (AVH) without FHF. Further dissection of the NF-kB complex in supershift assays demonstrated complete absence of p65 in the NF-kB complex, which is formed by homodimerization of the p50 component in pregnant FHF patients. Western blotting and immunohistochemical analysis of the expression of p50 and p65 proteins both showed higher levels of p50 expression and a complete absence or a minimal expression of p65, indicating its nonparticipation in NF-kB-dependent transactivation in pregnant FHF patients. We suggest that the exclusion of p65 from the NF-kB transactivation complex seems to be a crucial step that may cause deregulated immunity and severe liver damage, leading to the death of the patient. Our findings provide a molecular basis, for developing novel therapeutic approaches.

Possible involvement of cytokine gene polymorphisms in fulminant hepatitis

BACKGROUND AND AIM

Host genetic factors have been reported as influencing the progress to fulminant hepatitis (FH). Our previous data showed the serum level of tumor necrosis factor (TNF)-alpha influenced by gene polymorphisms to be markedly increased. It was investigated whether polymorphisms in the IL-10 gene, in addition to TNF-alpha and -beta gene polymorphisms, might contribute to the pathogenesis of FH.

METHODS

We analyzed 42 patients with FH, 78 patients with acute hepatitis (AH), and 149 healthy subjects (control). IL-10 polymorphism sites at promoter regions -1028, -819, -592; TNF-alpha polymorphism sites at promoter regions -1031, -863, -857, -308, -238; and TNF-beta first intron Nco1 sites were studied. IL-10 gene polymorphisms were classified into three groups: low IL-10-producing haplotypes (ATA/ATA), intermediate haplotypes (ATA or CCA/CCA), and high haplotypes (ATA/ATG or CCG).

RESULTS

The allelic frequency of B2 in the TNF-beta gene was significantly higher in FH patients compared with the control group. The three groups showed no differences in polymorphisms of positions -1031, -863, -857, -308 and -238 in the TNF-alpha gene. The frequency of low IL-10-producing haplotypes tended to be higher in FH patients compared with control and that of high IL-10-producing haplotype tended to be lower in FH patients compared with control. The carrier rate with both the IL-10 haplotype and the TNF-beta gene B2/B2 was significantly higher than control.

CONCLUSION

Variations of cytokine polymorphisms including IL-10 and TNF-beta genes may be attributable to the pathogenesis of FH.

Unusual cardiac features in cholestatic hepatitis A in an adolescent: Improvement with corticosteroid treatment

Hepatitis A is one of the most frequent infectious liver diseases affecting children worldwide. Extra-hepatic manifestations of acute hepatitis A virus are rare in pediatric age group. We report a case of a 16-year-old, otherwise healthy adolescent who had viral hepatitis A with cardiac manifestations. The patient is the first pediatric case of hepatitis A with a combination of hypotension, persistent bradycardia and progressive cholestasis.

Variable Number of Tandem Repeats of TNF Receptor Type 2 Promoter as Genetic Biomarker of Susceptibility to Develop Invasive Pulmonary Aspergillosis

Tumor necrosis factor alpha (TNF-alpha) and lymphotoxin alpha (LT-alpha) are pivotal mediators of inflammatory responses in fungal infection diseases. We hypothesized that polymorphisms in genes of these cytokines or their receptors might increase the susceptibility of hematologic patients to develop invasive pulmonary aspergillosis (IPA). One hundred two hematologic patients and 124 age-matched controls were enrolled in the study, and the following standard single nucleotide polymorphisms were investigated: TNF-alpha -308 and +489, LT-alpha +252 and Tumor Necrosis Factor Receptor 2 (TNFR2) +676. Variable number of tandem repeats (VNTRs) at position -322 of the TNFR2 gene were also studied. Genotypic and allelic frequencies were similar between patients and controls. IPA was diagnosed in 54 of the 102 patients according to consensus criteria published by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group. TNF-alpha and LT-alpha polymorphisms were not associated with presence of IPA. Susceptibility to IPA was strongly associated with VNTR at position -322 in the promoter region of the TNR2 gene (p = 0.029) but was not associated with the presence of TNFR2 +676 polymorphism. A genetic difference in TNFR2 promoter VNTR may play a major role in susceptibility to IPA infection.

Reduced monocyte HLA-DR expression: a novel biomarker of disease severity and outcome in acetaminophen-induced acute liver failure

Acute liver failure (ALF) shares striking similarities with septic shock where a decrease in HLA-DR expression on monocytes is associated with disease severity and predicts outcome. We investigated monocyte HLA-DR expression in ALF in relation to inflammatory mediator levels and clinical outcome. Monocyte HLA-DR expression was determined in 50 patients with acetaminophen-induced ALF (AALF) and 20 non-acetaminophen-induced ALF (NAALF). AALF patients were divided into dead/transplanted (AALF-NS, n = 26) and spontaneous survivors (AALF-S, n = 24). Fifty patients with chronic liver disease (CLD) and 50 healthy volunteers served as controls. Monocyte HLA-DR expression was determined by double-color flow-cytometry with monoclonal antibodies detecting HLA-DR and monocyte specific CD14. Serum levels of interleukin (IL) -4, -6, -10, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma were concomitantly measured by ELISA. Compared to healthy volunteers (75%) and CLD (67%) monocyte HLA-DR percentage expression was lower in AALF (15%, P < .001) and NAALF (22 %, P < .001). Compared to AALF-S, AALF-NS had lower monocyte HLA-DR % (11% vs. 36%, P < .001) and higher levels of IL-4, IL-6, IL-10 and TNF-alpha (P < .001). HLA-DR percentage negatively correlated with INR, blood lactate, pH and levels of encephalopathy (r = -0.8 to -0.5, P < .01), IL-10 (r = -0.8, P < .0001), TNF-alpha (r = -0.4, P = .02). HLA-DR percentage level <or=15% has a 96% sensitivity and 100% specificity and 98% accuracy in predicting poor prognosis. In conclusion, the strong relationship of monocyte HLA-DR expression with indices of disease severity, mediators of inflammation and outcome indicates a key role for this molecule as a biomarker of disease severity and prognosis.

Pathogenesis of herpes simplex hepatitis in macrophage-depleted mice: possible involvement of tumor necrosis factor-alpha and inducible nitric oxide synthase in massive apoptosis

Massive liver cell death provoked in silica-treated mice subsequently infected with herpes simplex virus (HSV)-1 is very similar pathohistologically to the cell death observed in human fulminant hepatitis. Previously, we have shown this liver cell death to be extensive apoptosis. In the present study, we examined various factors related to liver damage patho- and immunologically, as well as by reverse transcription-polymerase chain reaction. Tumor necrosis factor (TNF)-alpha, inducible nitric oxide synthase (iNOS), interferon (IFN)-alpha, and interleukin-6 mRNAs were detected to a much greater extent in silica-treated mice compared with control mice after HSV-1 infection, and excessive expression of iNOS mRNA and cytokine mRNAs in the liver may be closely related to massive liver cell apoptosis. The apoptosis was less related to the fas ligand than to TNF-alpha. Silica blockage of macrophages makes the liver cell extremely vulnerable to HSV-1 infection, and it induced expression of E-selectin and neutrophil margination in the liver. Subsequent HSV-1 infection induced excessive production of iNOS and cytokines, particularly TNF-alpha, but administration of anti-TNF-alpha antibody or NG-monomethyl-L-arginine was not completely efficacious for the survival of the mice. Overproduction of free radicals in combination with cytokines, such as TNF-alpha, IL-6 and IFN-alpha, may result in hepatic cell apoptosis.

The role of histamine H1 receptor and H2 receptor in LPS-induced liver injury

To examine the role of histamine H1 and H2 receptors in the regulation of lipopolysaccharide (LPS)-induced liver injury, a combination of D-galactosamine and LPS (GalN/LPS) was administered to histamine H1 receptor knockout (H1-R KO) and H2 receptor knockout (H2-R KO) mice. The numbers of necrotic and apoptotic hepatocytes in the liver, as well as the levels of serum aspartate transaminase (AST) and alanine transaminase (ALT), were increased significantly by GalN/LPS treatment compared to the appropriate controls. Pretreatment with histamine ameliorated the GalN/LPS-induced necrotic and apoptotic changes in the hepatocytes and inhibited the elevation of serum AST and ALT levels. Histamine attenuated the GalN/LPS-induced increases in the levels of TNF-alpha, but augmented those of IL-10 both in the liver and serum. Histamine inhibited the GalN/LPS-induced caspase-3 activity in the liver. Furthermore, these effects of histamine were completely or partially attenuated in H2-R KO mice, but not in H1-R KO mice. Peritoneal macrophages from H2-R KO mice exhibited blunted changes in the effects of histamine on LPS-induced TNF-alpha and IL-10 production in vitro compared to the wild-type (WT) controls. In summary, the present findings suggest that the histamine H2-R-TNF-alpha and -IL-10 pathways play protective roles in endotoxin-induced hepatic injury.

Stem cell factor restores hepatocyte proliferation in IL-6 knockout mice following 70% hepatectomy

Stem cell factor (SCF) is a molecule with known proliferative effects on hematopoietic cells. More recent studies suggest that this molecule may also have effects on cellular differentiation and proliferation in other types of cells. The current investigations demonstrate that there is a large reservoir of SCF in the liver, that hepatic SCF levels change dramatically following partial hepatectomy in mice, and that SCF blockade, either by administration of anti-SCF antibodies or by using genetically altered, SCF-deficient mice, inhibits hepatocyte proliferation after partial hepatectomy; if SCF is replaced in the genetically SCF-deficient mice after partial hepatectomy, hepatocyte proliferation is restored to that seen in WT animals. Furthermore, SCF administration to IL-6 knockout mice also restores hepatocyte proliferation to normal. In vitro studies using primary mouse hepatocytes demonstrate that SCF causes hepatocyte proliferation and is induced by IL-6 and that treatment with anti-SCF antibodies inhibits IL-6-induced hepatocyte proliferation. Further in vivo studies in IL-6 knockout mice demonstrate that SCF administration to these animals increases p-stat3 levels, suggesting that the SCF-induced increase in hepatocyte proliferation in this system is stat3-mediated.

The beneficial effects of protein tyrosine kinase inhibition on the circulatory failure induced by endotoxin in the rat

Implication of enhanced activity of tyrosine kinases has been established in the pathophysiology of many diseases associated with local (e.g., atherosclerosis) or systemic (e.g., septic shock) inflammation. The main objective of this study was to elucidate whether tyrosine kinase and nitric oxide were involved in endotoxin-induced impairment of vascular responses to sympathetic nerve stimulation (SNS) in rat isolated mesenteric bed. Therefore, the effects of genistein, an inhibitor of protein tyrosine kinase, and L-NAME (N-nitro-L-arginine methyl ester), an inhibitor of nitric oxide synthase, on endotoxin-induced shock were investigated in the thiopental-anesthetized rats. We also studied the effects of endotoxin on the vasoconstrictor responses to SNS in the rat isolated perfused mesenteric bed. Endotoxin injection (10 mg kg(-1), i.p.) produced a marked hypotension and a reduction of the pressor responses elicited by phenylephrine (0.1, 0.3, and 3 microg kg(-1), i.v.). Pretreatment of the rats with either genistein (10 mg kg(-1) i.p., 2 h before endotoxin injection), L-NAME (0.1 mg kg(-1), i.p., 30 min before endotoxin injection), or a combination of both attenuated the hypotension caused by endotoxin. SNS in the rat isolated perfused mesenteric bed caused a frequency-dependent vasoconstrictor response, which was abolished by tetrodotoxin (10(-7) M), prazoscin (10(-7) M), and guanethidine (10(-7)M). In mesenteric vascular beds removed from rats injected with endotoxin, the vasoconstrictor responses to SNS were markedly impaired. Although genistein and L-NAME pretreatment attenuated the vascular hyporeactivity to phenylephrine, they did not improve the impaired SNS response of the isolated vascular bed of endotoxin-treated animals. These results indicate that genistein and L-NAME pretreatment prevent the hypotension and the delayed hyporeactivity to phenylephrine induced by endotoxin, but they failed to restore the vascular hyporeactivity to SNS.

The systemic inflammatory response syndrome in acute liver failure

The systemic inflammatory response syndrome (SIRS) in acute liver failure (ALF), in which infection is common, has not been studied. In this study, SIRS components were recorded on admission and during episodes of infection, in 887 ALF patients admitted to a single center during an 11-year period. Overall, 504 (56.8%) patients manifested a SIRS during their illness, with a maximum of 1, 2, and 3 concurrent SIRS components in 166, 238, and 100 patients, respectively. In 353 (39.8%) patients who did not become infected, a SIRS on admission was associated with a more critical illness, subsequent worsening of encephalopathy, and death. Infected patients more often developed a SIRS and one of greater magnitude. The magnitude of the SIRS in 273 patients with bacterial infection correlated with mortality, being 16.7%, 28.4%, 41.2%, and 64.7% in patients with 0, 1, 2, and 3 maximum concurrent SIRS components, respectively. Similar correlations with mortality were seen for SIRS associated with fungal infection, bacteremia, and bacterial chest infection. Fifty-nine percent of patients with severe sepsis died, as did 98% of those with septic shock. A significant association was found between progressive encephalopathy and infection. Infected patients with progressive encephalopathy manifested more SIRS components than other infected patients. For patients with a SIRS, the proportions of infected and noninfected patients manifesting worsening encephalopathy were similar. In ALF, the SIRS, whether or not precipitated by infection, appears to be implicated in the progression of encephalopathy, reducing the chances of transplantation and conferring a poorer prognosis.

Significance of soluble TNF receptor-I in acute-type fulminant hepatitis

OBJECTIVE

Fulminant hepatitis is associated with apoptosis of hepatocytes, which is mediated via Fas and tumor necrosis factor (TNF) receptors. The clinical significance of apoptotic factors and these receptors was investigated in fulminant hepatitis.

METHODS

Serum levels of TNF-alpha, soluble TNF receptor-I and -II, soluble Fas antigen, and Fas ligand were measured. Then, the relationships between these parameters and the severity or prognosis of fulminant hepatitis were studied.

RESULTS

Serum levels of TNF-alpha, soluble TNF receptor-I, and soluble TNF receptor-II were increased in acute-type fulminant hepatitis. In particular, soluble TNF receptor-I was significantly higher than in patients with subacute-type fulminant hepatitis, severe acute hepatitis, acute hepatitis, or healthy controls. The soluble TNF receptor-I level continued to increase or remained high in patients who died of acute-type fulminant hepatitis, and eight of nine patients had a level >10 ng/ml. In contrast, the soluble TNF receptor-I level remained <10 ng/ml in survivors. Soluble Fas and soluble Fas ligand levels tended to increase in all types of acute liver disease and were not specific to fulminant hepatitis.

CONCLUSION

Our findings suggested that monitoring the soluble TNF receptor-I level may help to assess the prognosis of acute-type fulminant hepatitis and that TNF might be associated with massive hepatic necrosis.

Plasma cytokine levels and coagulation and complement activation during use of the extracorporeal liver assist device in acute liver failure

Multiple organ failure frequently occurs in patients with acute liver failure, and this has been associated with increased cytokine production. Treatment by hemoperfusion with an extracorporeal liver assist device (ELAD) containing human liver-derived cells was performed in 12 patients with acute liver failure. Over the first 6 h, there were significant increases in plasma tumor necrosis factor alpha (TNFalpha; from 114+/-54 pg/ml [mean+/-SEM] to 236+/-161 pg/ml, p < 0.05) and interleukin (IL)-6 (260+/-121 pg/ml to 445+/-149 pg/ml, p < 0.05) but not in interferon gamma (IFNgamma). A similar pattern with a small peak increase was observed for complement C5b-9 complex. Plasma C-reactive protein (CRP) and thrombin antithrombin (TAT) III complex showed small peaks after 24 h of ELAD hemoperfusion. No such changes were seen in 12 control patients with acute liver failure who were treated with intensive care alone. These transitory effects, without changes in blood pressure, are likely to be due to the contact of the blood with the dialyzer membrane. There was no evidence of the clearance of cytokines by the ELAD.

Mechanism of action and value of N-acetylcysteine in the treatment of early and late acetaminophen poisoning: a critical review

INTRODUCTION

The mechanism of action of N-acetylcysteine in early acetaminophen poisoning is well understood, but much remains to be learned of the mechanism of its possible benefit in acetaminophen poisoning presenting beyond 15 hours.

METHODS

Selective review of medical literature. N-acetylcysteine should be used in all cases of early acetaminophen poisoning where the plasma acetaminophen concentration lies "above the line;" which line is chosen depends on individual preference and whether enzyme induction is suspected. Particular care should be taken with the use of the nomogram for patients with chronic excess ingestion of acetaminophen or for those who have taken slow-release formulations.

CONCLUSIONS

While there is a trend suggesting a beneficial effect of N-acetylcysteine in some patients presenting beyond 15 hours, further research is necessary to establish just how effective N-acetylcysteine is, particularly in patients presenting with fulminant hepatic failure. Candidate mechanisms for a beneficial effect in-clude improvement of liver blood flow, glutathione replenishment, modification of cytokine production, and free radical or oxygen scavenging. Hemody-namic and oxygen delivery and utilization parameters must be monitored carefully during delayed N-acetylcysteine treatment of patients with fulminant hepatic failure, as unwanted vasodilation may be deleterious to the maintenance of mean arterial blood pressure.

Tumor necrosis factor genomic polymorphism and outcome of acetaminophen (paracetamol)-induced acute liver failure

BACKGROUND/AIMS

High levels of tumor necrosis factor-alpha are associated with an increased risk of severe encephalopathy in acute liver failure, and experimental studies suggest that tumor necrosis factor-alpha plays a role in the development of acetaminophen (paracetamol)-induced liver injury and associated multiple organ failure. Inter-individual variations in the production of tumor necrosis factor-alpha have been linked to genomic polymorphisms within the tumor necrosis factor-alpha locus. This study examined whether specific tumor necrosis factor polymorphisms are associated with variations in the severity of clinical features in acetaminophen-induced acute liver failure.

METHODS

Genotypes at the -308 tumor necrosis factor A and tumor necrosis factor B Nco1 polymorphic sites were determined in 97 patients with severe acetaminophen-induced hepatotoxicity and 109 controls, using polymerase chain reaction and restriction fragment length polymorphism. The relationship between liver injury, multiple organ failure and encephalopathy, determined retrospectively from clinical notes and genotype, was examined.

RESULTS

No significant association was found between either tumor necrosis factor A or B genotype and parameters for multiple organ failure or liver injury. The tumor necrosis factor B1B1 genotype was significantly under-represented in those patients developing severe encephalopathy (p=0.03) and a multivariate logistic regression analysis confirmed the influence of tumor necrosis factor B genotype (p<0.01). The association was independent of the HLA class II allele DRB1*03, which is closely linked to the TNFB locus.

CONCLUSIONS

The development of acute liver failure is unlikely to be primarily sepsis driven. However, the apparent protective effect of the tumor necrosis factor B1B1 genotype on the development of severe encephalopathy may be related to the effects of this genotype on tumor necrosis factor-alpha production in sepsis.

Effects of tyrphostins and genistein on the circulatory failure and organ dysfunction caused by endotoxin in the rat: a possible role for protein tyrosine kinase

1 Here we compared the effects of various inhibitors of the activity of protein tyrosine kinase on (i) the expression of the activity of the inducible isoform of nitric oxide (NO) synthase (iNOS) caused by endotoxin (lipopolysaccharide, LPS) in cultured macrophages, (ii) the induction of iNOS and cyclooxygenase 2 (COX-2) protein and activity in rats with endotoxaemia, and (iii) the circulatory failure and organ dysfunction caused by LPS in the anesthetized rat. 2 Activation of murine cultured macrophages with LPS (1 microgram ml-1) resulted, within 24 h, in a significant increase in nitrite (an indicator of the formation of NO) in the cell supernatant. This increase in nitrate was attenuated by the tyrphostins AG126, AG556, AG490 or AG1641 or by genistein in a dose-dependent fashion (IC50: approximately 15 microM). In contrast, tyrphostin A1 (an analogue of tyrphostin AG126) or daidzein (an analogue of genistein) had no effect on the rise in nitrite caused by LPS. 3 Administration of LPS (E. coli, 10 mg kg-1, i.v.) caused hypotension and a reduction of the pressor responses elicited by noradrenaline (NA, 1 microgram kg-1, i.v.). Pretreatment of rats with the tyrphostins AG126, AG490, AG556, AG1641 or A1 attenuated the circulatory failure caused by LPS. Although genistein attenuated the vascular hyporeactivity to NA, it did not affect the hypotension caused by LPS. Daidzein did not affect the circulatory failure caused by LPS. 4 Endotoxaemia for 360 min resulted in rises in the serum levels of (i) urea and creatinine (indicators of renal failure), (ii) alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin and gamma-glutamyl transferase (gamma GT) (indicators of liver injury/dysfunction), lipase (an indicator of pancreatic injury) as well as lactate (an indicator of tissue hypoxia). None of the tyrosine kinase inhibitors tested had a significant effect on the rise i the serum levels of urea, but the tyrphostins AG126, AG556 or A1 significantly attenuated the rises in the serum level of creatinine caused by LPS. In addition, all tyrphostins and genistein attenuated the liver injury/failure, the pancreatic injury, the hypoglycaemia and the lactic acidosis caused by LPS. In contrast, daidzein did not reduce the organ injury/dysfunction or the lactic acidosis caused by LPS. 5 Injection of LPS resulted (within 90 min) in a substantial increase in the serum level of tumor necrosis factor alpha (TNF alpha), which was attenuated by pretreatment of LPS-rats with any of the tyrphostins used. Genistein, but not daidzein, also reduced the rise in the serum levels of TNF alpha caused by LPS. Endotoxaemia for 6 h also resulted in a substantial increase in the expression of iNOS and COX-2 protein and activity in the lung, which was attenuated by pretreatment of LPS-rats with the tyrphostins AG126, AG556 or genistein, but not by daidzein. 6 Thus, tyrphostins (AG126, AG556, AG1641 or A1) and genistein, but not daidzein (inactive analogue of genistein), prevent the (i) circulatory failure, (ii) the multiple organ dysfunction (liver and pancreatic dysfunction/injury lactacidosis, hypoglycaemia), as well as (iii) the induction of iNOS and COX-2 protein and activity in rats with endotoxic shock.

Effect of calpain inhibitor I, an inhibitor of the proteolysis of I kappa B, on the circulatory failure and multiple organ dysfunction caused by endotoxin in the rat

1. We compared the effects of calpain inhibitor I (inhibitor of the proteolysis of I kappa B and, hence, of the activation of nuclear factor kappa B (NF kappa B) and dexamethasone on (i) the circulatory failure, (ii) multiple organ dysfunction and (iii) induction of the inducible isoforms of nitric oxide (NO) synthase (iNOS) and cyclo-oxygenase (COX-2) in anaesthetized rats with endotoxic shock. 2. Injection of lipopolysaccharide (LPS, E. coli, 10 mg kg-1, i.v.) resulted in hypotension and a reduction of the pressor responses elicited by noradrenaline. This circulatory dysfunction was attenuated by pretreatment of LPS-rats with calpain inhibitor I (10 mg kg-1, i.v., 2 h before LPS) or dexamethasone (1 mg kg-1, i.v.). 3. Endotoxaemia also caused rises in the serum levels of (i) urea and creatinine (renal dysfunction), (ii) alanine aminotransferase (ALT), aspartate aminotransferase (AST) (hepatocellular injury), bilirubin and gamma-glutamyl transferase (gamma GT) (liver dysfunction), (iii) lipase (pancreatic injury) and (iv) lactate. Calpain inhibitor I and dexamethasone attenuated the liver injury, the pancreatic injury, the lactic acidosis as well as the hypoglycaemia caused by LPS. Dexamethasone, but not calpain inhibitor I, reduced the renal dysfunction caused by LPS. 4. Endotoxaemia for 6 h resulted in a substantial increase in iNOS and COX-2 protein and activity in lung and liver, which was attenuated in LPS-rats pretreated with calpain inhibitor I or dexamethasone. 5. Thus, calpain inhibitor I and dexamethasone attenuate (i) the circulatory failure, (ii) the multiple organ dysfunction (liver and pancreatic dysfunction/injury, lactic acidosis, hypoglycaemia), as well as (iii) the induction of iNOS and COX-2 protein and activity in rats with endotoxic shock. We propose that prevention of the activation of NF-kappa B in vivo may be useful in the therapy of circulatory shock or of disorders associated with local or systemic inflammation.

Tumor necrosis factor alpha gene expression and the response to interferon in chronic hepatitis C

Tumor necrosis factor alpha (TNF-alpha) is a cytokine with pleiotropic properties that is induced in a variety of pathological situations including viral infections. In this work, we analyzed the expression of TNF-alpha gene in patients with chronic hepatitis C. Serum TNF-alpha levels were found to be elevated in all chronic hepatitis C patients including those cases presenting sustained biochemical remission of the disease after interferon therapy. Untreated patients with chronic hepatitis C showed increased TNF-alpha messenger RNA (mRNA) levels in the liver and mononuclear cells as compared with healthy controls. After completion of treatment with interferon, patients experiencing sustained complete response showed values of TNF-alpha mRNA, both in the liver and in peripheral mononuclear cells, within the normal range, significantly lower than patients who did not respond to interferon and than those with complete response who relapsed after interferon withdrawal. Pretreatment values of TNF-alpha mRNA were lower in long-term responders to interferon than in cases who failed to respond to the treatment. Values of TNF-alpha mRNA in the liver or in mononuclear cells were higher in specimens with positive hepatitis C virus (HCV) RNA than in those samples where the virus was undetectable. Neither the intensity of the liver damage nor the amount of HCV RNA in serum or in cells showed correlation with the levels of TNF-alpha transcripts in peripheral mononuclear cells but it was found that high TNF-alpha values were associated with genotype 1b. In conclusion, there is an enhanced expression of TNF-alpha in HCV infection. High levels of this cytokine may play a role in the resistance to interferon therapy.

Prevention of endotoxin-induced acute lethality in Propionibacterium acnes-primed rabbits by an antibody to leukocyte integrin beta 2 with concomitant reduction of cytokine production

Acute lethality was induced in rabbits by the sequential injection of Propionibacterium acnes and lipopolysaccharide (LPS). P. acnes induced the infiltration of inflammatory cells into the liver lobules during the early phase, and LPS in the late phase caused death in association with pathological changes mimicking hepatocellular necrosis or degeneration around infiltrated mononuclear cells and fibrin deposition in the liver, lung, and kidney, suggestive of a systemic Schwartzman-like reaction. These pathological changes were accompanied by the elevation of plasma tumor necrosis factor (TNF) and interleukin-8 (IL-8) levels. A neutralizing antibody to a leukocyte adhesion molecule, integrin beta 2 (CD18), administered at the time of LPS challenge, prevented reduced the elevation of plasma TNF and IL-8 levels. An anti-TNF alpha antibody but not an anti-IL-8 mediator in this model. These results indicate that CD18 is critically involved in vivo in activating leukocytes to produce cytokines in response to LPS.

Tumor necrosis factor receptors in patients with chronic hepatitis B virus infection

BACKGROUND/AIMS

Patients with chronic hepatitis B infection have elevated plasma tumor necrosis factor (TNF) alpha levels. Two TNF-alpha receptors have been identified, each responsible for distinct TNF-alpha activities. The aim of this study was to evaluate the biological function of the elevated TNF-alpha in chronic hepatitis B virus infection by examining the two TNF signaling pathways in the evolution of hepatitis B-related liver injury.

METHODS

The hepatic expression of the two TNF receptors and the corresponding serum levels of the soluble forms of both TNF receptors were determined and correlated with hepatic inflammation and virus replication in 98 chronic hepatitis B surface antigen carriers. Forty hepatitis B e antigen-positive patients were also studied prospectively, while on interferon alfa treatment, to examine the TNF receptor response during viral clearance.

RESULTS

In chronic hepatitis B virus infection, the hepatic expression and serum levels of TNF receptors, in particular 75-kilodalton TNF receptor subtype (TNF-R p75), are significantly enhanced in association with hepatic inflammation and hepatocytolysis but not with hepatitis B virus replication. During interferon alfa treatment, a significant increase of soluble TNF-R p75 always precedes the hepatitis B e antigen antibody against hepatitis B e antigen seroconversion in responders to treatment.

CONCLUSIONS

In chronic active hepatitis B infection, there is an up-regulation of the TNF receptor system, preferentially the TNF-R p75 signaling pathway, which suggests that the TNF-alpha/TNF receptor system has an important role in the pathogenesis of liver damage and viral clearance.

Enhanced tumor necrosis factor alpha in coronavirus but not in paracetamol-induced acute hepatic necrosis in mice

Previous reports have demonstrated that tumor necrosis factor alpha (TNF-alpha) plays an important role in the pathogenesis of fulminant hepatic necrosis. The purpose of this experimental study was to measure TNF-alpha blood activity in paracetamol-induced liver necrosis and in coronavirus (MHV3)-induced fulminant hepatitis in mice. No elevation of TNF-alpha activity was found in hepatic failure complicating paracetamol poisoning. In contrast, TNF-alpha activity significantly increased in response to MHV3, reaching 16.3 +/- 5.5 U/ml from 24 h post infection (P less than 0.01). This augmentation was observed even though the virus was not detectable in the liver. Serum alanine aminotransferase levels were low and no histological lesion was observed. In conclusion, our study further supports the implication of TNF-alpha in virus-induced hepatitis failure and confirms that paracetamol poisoning does not cause increased TNF-alpha activity in the circulation.