Genetic heterogeneity of the envelope 2 gene and eradication of hepatitis C virus after a second course of interferon-alpha

The heterogeneity of the envelope 2 (E2) gene of the hepatitis C virus (HCV) was involved in the sensitivity of HCV to interferon-alpha (IFN-alpha). To assess the factors leading to virus eradication by IFN-alpha, patients whose first treatment by IFN-alpha failed and who had virus eradication after a second treatment were studied. These patients were paired with subjects in whom both treatments failed. The phosphorylation homology domain of the E2 gene (E2-PHD) had no sequence variation between the two stages in both groups of patients. Therefore, this region has no clinical predictive value within a specific genotype. The hypervariable region 1 (HVR1) was analyzed by cloning and sequencing 20 clones per sample. Comparison of samples showed that the change in quasispecies induced by the first IFN-alpha therapy could be associated with virus elimination obtained after a second treatment. The greater proportion of nonsynonymous mutations that was noted before the second treatment in responders suggest that pretherapeutic immune response is a major factor determining virus elimination and that the immune status of these patients changed between the first and the second treatment.

Infection of HepG2 cells with recombinant adenovirus encoding the HCV core protein induces p21(WAF1) down-regulation -- effect of transforming growth factor beta

BACKGROUND/AIMS

Chronic infection with hepatitis C virus leads to liver cirrhosis and hepatocellular carcinoma. Hepatocellular carcinoma is sometimes associated with p53 dysfunction and decreased p21(WAF1) expression. The p21(WAF1) gene is a major target of p53, and p21(WAF1) protein regulates the activities of cyclin/CDK complexes involved in cell cycle control and tumor formation. Because core protein has oncogenic properties, we investigated the expression of p21(WAF1) following core expression.

METHODS

We analyzed by Western blot, Northern blot and transfection the expression of p21(WAF1) in HepG2 cell line under transient expression of Hepatitis C core protein by recombinant-adenoviral infection.

RESULTS AND DISCUSSION

Infection of HepG2 with core-encoding viruses induced the down-regulation of p21(WAF1) expression. This effect is due to a decrease in the p21(WAF1) gene transcription and of the p21(WAF1) protein half-life. These results support a role for Hepatitis C virus core protein in cell transformation. We also found also that the transforming growth factor beta can counteract the core-induced p21(WAF1) down-regulation. The antagonist effect of TGF beta, or of other molecules, on p21(WAF1) expression may be of particular interest for the treatment of HCV-positive hepatocellular carcinoma.

Histological features and HLA class II alleles in hepatitis C virus chronically infected patients with persistently normal alanine aminotransferase levels

OBJECTIVE

A significant proportion of individuals with chronic hepatitis C virus (HCV) infection have persistently normal alanine aminotransferase (ALT) levels. Although data are controversial, such patients usually have weaker histological damage and a lower progression rate of fibrosis. The aims of this study were: (1) to compare demographic, virological, and histological parameters of HCV patients with normal ALT values with those of HCV patients with elevated ALT levels; and (2) to determine whether HLA class II alleles contribute to the persistence of normal ALT levels in HCV patients.

PATIENTS AND METHODS

Eighty three patients with chronic HCV infection and persistently normal ALT values (group 1) and 233 patients with chronic HCV infection and elevated ALT levels (group 2) were studied. Histological features were expressed using Knodell and Metavir scores. HLA DRB1* and DQB1* genotyping was performed using hybridisation with sequence specific oligonucleotides after genomic amplification. The kappa2 and Fisher's exact tests were used to compare discrete variables and phenotype frequencies between the two groups, and Wilcoxon's test was used for continuous variables. A multivariate logistic regression model was used to determine which variables predicted normal ALT values.

RESULTS

ALT levels were correlated with the severity of liver damage. In group 1, 93% of patients had an F0 or F1 Metavir index of fibrosis compared with 47% of patients in group 2 (p<0.001). A longer duration of infection (p<0.001) and increased DRB1*11 phenotype frequency (pc=0.03) were observed among patients with normal ALT. The two groups did not differ with regard to the mode of contamination or viral genotype. After logistic regression, young age (p=0.0008), female sex (p=0.01), long duration of infection (p=0.0001), and HLA DRB1*11 (p=0.050) were more strongly associated with persistence of normal ALT.

CONCLUSIONS

Our study confirms that patients with chronic hepatitis C and normal ALT levels have less severe liver disease than those with elevated ALT levels. This particular biochemical outcome may be explained, at least in part, by host immunogenetic factors such as the presence of HLA-DRB1*11.

[Hepatitis C and pregnancy]

PURPOSE

Today, the natural course of hepatitis C virus (HCV) infection during pregnancy and the prevalence of mother-to-child transmission are better known.

CURRENT KNOWLEDGE AND KEY POINTS

Antenatal screening for HCV infection needs to be proposed to women with risk factors. Viral replication needs to be confirmed by PCR in pregnant women with antibodies against HCV. To date, the clinical course of pregnancy and the mode of delivery have not been changed by HCV infection. Rates of vertical transmission of HCV are about 6% in women with HCV alone and 15% in women co-infected with HIV. A screening for HCV markers is required 18 months after delivery for infants born to HCV mothers. Because of the relatively low rate of HCV vertical transmission, pregnancy can be allowed in infected women. However, taking into account the efficacy of new antiviral strategies, treatment of HCV infection could be proposed before pregnancy.

FUTURE PROSPECTS AND PROJECTS

In case of HCV infection, a careful follow-up of both mother and newborns is required. Long-term follow-up of infected infants is needed to assess the consequences of perinatal HCV infection.

Cryoglobulinemia vasculitis

Cryoglobulins are immunogloblulins that persist in the serum, precipitate with cold temperature, and resolubilize when rewarmed. Mixed cryoglobulins, composed of different immunoglobulins, with a monoclonal component in type II and only polyclonal immunoglobulins in type III, are associated with connective tissue, malignant hematologic, or obvious infectious diseases. The syndrome of mixed cryoglobulinemia represents the consequence of an immune complex-type vasculitis. It is characterized by the clinical triad of purpura, arthralgia, and asthenia, and may involve numerous organs, particularly the peripheral nervous system and the kidneys. Mixed cryoglobulinemia frequently is associated with clinical and biologic evidence of liver disease. It seems fairly clear that mixed cryoglobulinemia is often a manifestation of underlying chronic active or persistent hepatitis. In the last 10 years, many studies have demonstrated that infection with hepatitis C virus is involved in the pathogenesis of most mixed cryoglobulinemia vasculitis. This review analyzes the main published data of hepatitis C virus-mixed cryoglobulinemia, the role of liver alterations, the predictive factors associated with mixed cryoglobulin production in hepatitis C virus patients and whether its character is symptomatic, and the different types of vasculitis associated with hepatitis C virus chronic infection and their treatments.

Maintenance therapy with gradual reduction of the interferon dose over one year improves histological response in patients with chronic hepatitis C with biochemical response: results of a randomized trial

BACKGROUND/AIMS

Our aim was to assess whether histological response was improved by continuing interferon-alpha (IFN) treatment in patients with chronic hepatitis C (HCV) with a biochemical response and no viral clearance after a usual IFN treatment.

METHODS

Fifty-seven patients with normal alanine aminotransferase (ALAT) levels and positive HCV RNA at the end of a 1 year IFN treatment were randomly assigned to either group 1 (n = 28) where IFN was stopped, or group 2 (n = 29) where IFN was continued for 1 more year with gradual reduction of the dose to keep serum ALAT activity below the upper limit of normal. Liver biopsies were obtained before, and then 6 months after the end of treatment.

RESULTS

Knodell's index improved between paired biopsies in group 2 (8.2+/-2.4 vs. 5.5+/-2.1), but not in group 1 (8+/-2.3 vs. 6.5+/-2). In post-treatment biopsies, the METAVIR activity score was significantly lower in group 2 than in group 1 (0.7+/-0.2 vs. 1.1+/-0.3, P < 0.05). In group 2, an improvement of the METAVIR fibrosis score was observed (1.3+/-0.4 vs. 1.1+/-0.2), whereas fibrosis progressed in group 1 (1.3+/-0.4 vs. 1.6+/-0.4).

CONCLUSIONS

Maintenance therapy by the minimal dose of IFN able to maintain biochemical response prevents histological progression in the sub-group of patients without virological response.

Nonstructural 3 protein of hepatitis C virus triggers an oxidative burst in human monocytes via activation of NADPH oxidase

It has been shown that oxidative stress occurs in chronic hepatitis C. Release of reactive oxygen species (ROS) from sequestered phagocytes and activated resident macrophages represents the predominant component of oxidative stress in the liver. However, little is known about the ability of the monocyte to produce ROS in response to protein of hepatitis C virus. In this study, we investigated the ROS production in human monocytes stimulated by several viral proteins of hepatitis C virus. Human monocytes from healthy blood donors were incubated with recombinant viral protein: Core, NS3, NS4, and NS5. ROS production was measured by chemiluminescence. Only NS3 triggered ROS production in human monocytes. Generated ROS were mainly the anion superoxide. NS3 also induced a rapid and transient increase in intracellular calcium concentration measured by a video digital microscopy technique. By using different metabolic inhibitors, we showed that ROS production requires calcium influx, tyrosine kinases, and the stress-activated protein kinase, p38. The study of p47(PHOX) phosphorylation and translocation showed that NADPH oxidase was activated and involved in ROS production induced by NS3. In a second experiment, NS3 inhibited the oxidative burst induced by phorbol 12-myristate 13-acetate. These results indicate that NS3 activates NADPH oxidase and modulates ROS production, which may be involved in the natural history of hepatitis C infection.

[Association of disseminated lupus erythematosus and Crohn's disease]

INTRODUCTION

Association of Crohn's disease and systemic lupus erythematosus is infrequent. We report an observation of Crohn's disease that appeared in an 18-year-old woman followed-up for systemic lupus erythematosus for four years.

EXEGESIS

The patient had all the clinical, biological and histological criteria of Crohn's disease and systemic lupus erythematosus was diagnosed according to the American Rheumatism Association criteria. On the base of this observation, we discuss the digestive manifestation of systemic lupus erythematosus and extradigestive manifestations of Crohn's disease.

CONCLUSION

The immunological background of both diseases was proposed to explain the mechanism of this rare association.

Reactive oxygen intermediates and eicosanoid production by kupffer cells and infiltrated macrophages in acute and chronic liver injury induced in rats by CCl4

OBJECTIVE AND DESIGN

The aim of the present study was to characterize during acute and chronic liver injury induced by CCl4, macrophage phenotypes and whether a change in reactive oxygen intermediates (ROI) and eicosanoids production by Kupffer cells (KC) was observed.

MATERIAL AND METHODS

Liver steato-necrosis and cirrhosis were induced in rats after 3 weeks and 9 weeks of CCl4 intoxication, respectively. Monocytes and tissue macrophages were identified by immunohistochemical study using monoclonal antibodies ED-1 and tissue macrophages using the antibody ED-2. The release of ROI and eicosanoids in response to the phorbol ester TPA (protein kinase activator) and to the calcium ionophore A23187 was assessed in cultivated cells.

RESULTS

As compared to healthy controls, livers of rats with steato-necrosis or cirrhosis exhibited a significant increase of ED-1 and ED-2 positive cells. Only KC from rats with liver steato-necrosis were found to have higher A23187, TPA + A23187 or opsonized zymosan induced ROI production than healthy controls (p < 0.01). After TPA + A23187 or opsonized zymosan stimulation, KC from both rats with steato-necrosis or cirrhosis produced more TxB2 and leukotrienes and less PGE2 as compared to healthy controls (p <0.05).

CONCLUSIONS

These results suggest an influx of monocytes into the liver during acute and chronic injury induced by CCl4. Functional changes of this inflammatory infiltrate have been demonstrated with an increase of ROI production only in the early stage of liver injury whereas a rise in KC leukotriene production and an imbalance between cytoprotective and cytotoxic prostanoids were observed at all stages of liver disease.

Study of host- and virus-related factors associated with spontaneous hepatitis C virus clearance

Epidemiologic parameters, virologic characteristics and frequency of HLA class II DR and DQ antigens were compared between 63 subjects with spontaneous hepatitis C virus clearance (group 1) and 282 patients with chronic active hepatitis C virus infection (group 2). DRB1*1101 and moreover DQB1*0301 alleles were more frequent in group 1 than in group 2 (33.8% vs. 14.7% and 64.4% vs. 28.6%; P=0.012 and P=0.003, respectively). The frequency of DQB1*02 was lower in group 1 than in group 2 (25.4% vs. 49%; P=0.04). No difference was observed in viral genotype distribution between group 1 and group 2. Univariate analysis showed that female sex and contamination by intravenous drug use were associated with self limited infection. However, by multivariate analysis, the only independent factor associated with hepatitis C virus RNA clearance was female sex (P=0.004). In conclusion, spontaneous hepatitis C virus RNA clearance is determined by class II antigens (mainly DQB1*0301) and female sex, while viral genotype plays no role.

[Association between polymyositis and hepatitis C infection. Treatment-related difficulties]

INTRODUCTION

Chronic hepatitis C virus infection is often associated with various auto-immune disorders. We report four cases of an association between polymyositis and hepatitis C virus infection. The course and the difficulties of therapy are discussed.

EXEGESIS

Among 510 consecutive patients infected by viral hepatitis C, we report four cases of polymyositis. Corticosteroids increased serum alanine aminotransferase levels in two cases, leading to severe liver injury in one patient. Worsening of polymyositis under interferon-alpha therapy was observed in one case. Clinical and biological stability were reported in another case. Aggravation of polymyositis with severe muscle weakness and dyspnea occurred in two patients after disruption of interferon-alpha treatment. Intravenous gamma globulins subsequently improved their condition, without biological worsening of viral hepatitis.

CONCLUSION

These observations suggest an association between hepatitis C virus infection and polymyositis. Because corticosteroids can induce adverse effects in the liver, intravenous gamma globulins could be used for the treatment of this particular form of polymyositis.

Genetic heterogeneity of hypervariable region 1 of the hepatitis C virus (HCV) genome and sensitivity of HCV to alpha interferon therapy

Hepatitis C virus (HCV) populations persist in vivo as a mixture of heterogeneous viruses called quasispecies. The relationship between the genetic heterogeneity of these variants and their responses to antiviral treatment remains to be elucidated. We have studied 26 virus strains to determine the influence of hypervariable region 1 (HVR-1) of the HCV genome on the effectiveness of alpha interferon (IFN-alpha) therapy. Following PCR amplification, we cloned and sequenced HVR-1. Pretreatment serum samples from 13 individuals with chronic hepatitis C whose virus was subsequently eradicated by treatment were compared with samples from 13 nonresponders matched according to the major factors known to influence the response, i.e., sex, genotype, and pretreatment serum HCV RNA concentration. The degree of virus variation was assessed by analyzing 20 clones per sample and by calculating nucleotide sequence entropy (complexity) and genetic distances (diversity). Types of mutational changes were also determined by calculating nonsynonymous substitutions per nonsynonymous site (K(a)) and synonymous substitutions per synonymous site (K(s)). The paired-comparison analysis of the nucleotide sequence entropy and genetic distance showed no statistical differences between responders and nonresponders. By contrast, nonsynonymous substitutions were more frequent than synonymous substitutions (P </= 0.05) in responders, but there was no significant difference in nonresponders. Nonsynonymous substitutions tended to be more frequent than synonymous substitutions in women (P = 0.06) but not in men. Nucleotide entropy and genetic distances were significantly related to serum RNA concentration (P </= 0.01). Our findings suggest that after controlling for the major determinants of interferon response, neither complexity nor diversity of the HVR-1 region is associated per se with virus eradication. Because a higher proportion of nonsynonymous substitutions than synonymous substitutions was found only in responders, host anti-HCV-specific immune response rather than viral factors may be playing an important role in the interferon response.

Expression of TNF-alpha and immunohistochemical distribution of hepatic macrophage surface markers in carbon tetrachloride-induced chronic liver injury in rats

In liver injury induced by carbon tetrachloride, secondary hepatic injury occurs from inflammatory processes originating from products released by activated Kupffer cells, which play a central role in hepatic inflammation. The purpose of our study was to demonstrate, in rats, the relationships between a function of the hepatic macrophages, TNF-alpha production and the state of activation of these cells, characterized by their phenotype, in the different phases of the process and development of fibrosis in a carbon tetrachloride-induced cirrhosis model. The immunohistochemical localization of proinflammatory cytokine TNF-alpha and surface surface makers (ED1 and ED2) was studied in hepatitis and cirrhosis in response to 3 and 9 weeks ingestion of carbon tetrachloride. After carbon tetrachloride ingestion, accompanying the increased necrosis, immunohistochemical analysis of liver tissue sections demonstrated the significantly increased number of cells expressing ED1, ED2 and TNF-alpha, compared to normal. The number of cells expressing the surface phenotypic markers of liver macrophages increased and this change was concomitantly associated with an increased cellular expression of TNF-alpha. Local macrophage proliferation and influx of newly recruited blood monocytes resulted in an increase of the macrophage population. The populational changes involved difference in functional activity and enhanced TNF-alpha expression. This cytokine expressed in the carbon tetrachloride-induced inflammatory process is associated with the development of fibrosis and may contribute to disease severity.

Study of the association between major histocompatibility complex class II genes and the response to interferon alpha in patients with chronic hepatitis C infection

OBJECTIVE

The aim of the study was to determine the influence of HLA class II genes on the response to interferon-alpha (IFN-alpha) in patients with chronic hepatitis C.

METHODS

The distribution of HLA DRB1 and DQB1 alleles was assessed in 170 caucasoïd patients treated with IFN-alpha for chronic hepatitis C. 50 patients had a long term sustained response to treatment whereas 120 patients were nonresponders.

RESULTS

Female sex, non-1 HCV genotype particularly genotype 2 and pretreatment low serum HCV RNA level were associated with long-term sustained response to IFN-alpha. A trend towards a higher prevalence of DRB1*07 allele in non responders than in patients with sustained response (45% vs. 28%, odds ratio 2.1; P < 0.05) on the one hand and of DQB1*06 allele in HCV genotype 1 patients with sustained response than in HCV genotype 1 nonresponders (75% vs 27.3%, odds ration 7.9; P < 0.02) on the other hand, were observed. However, none of these two differences remained significant after Bonferroni's correction.

CONCLUSION

Accordingly, we conclude that the response to IFN-alpha therapy is more tightly related to virus factors than to host's HLA class II genes.