Clinical implications of GBV-C/HGV infection in patients with "HCV-related" chronic hepatitis

Intra-host diversity and emergence of unique GBV-C viral lineages in HIV infected subjects in central China

GB virus C (GBV-C), which is highly prevalent among HIV/AIDS, seemed to slow the HIV disease progression. The HIV/GBV-C co-infected individuals may represent an interesting model for the investigation of the role played by HIV infection and/or the immune system in driving the evolution of the GBV-C viral populations. The present study investigated the prevalence and population dynamics of GB virus C in HIV infected individuals representing 13 geographic regions of Hubei Province of China. Approximately 37% of HIV-1 infected individuals were infected with GBV-C and genotype 3 is appeared to be predominant. Utilizing the 196 complete E2 nucleotide sequence data from 10 HIV/GBV-C infected individuals and employing coalescence based phylogenetic approaches; the present study has investigated the intra-host dynamics of GBV-C. The results revealed patient-specific unique GBV-C viral lineages and each viral lineage showed the evidence of rapid population expansion in respective HIV-1 infected patients, thus suggesting HIV-1 was unlikely to have been inhibiting effect on the GBV-C viral replication. GBV-C in all patients has experienced intense purifying selection, suggesting the GBV-C viral invasion and subsequent expansion within the HIV-1 infected hosts without any modification of the functional epitopes at their membrane protein. The finding of within host GBV-C recombinant sequences indicated recombination was one of the significant forces in the evolution and divergence of GBV-C.

Functionality of the immune system in patients with chronic hepatitis C: trial by superinfections and vaccinations

Viral infections, specifically chronic, markedly influence the host response to subsequent infections and vaccinations. Does this apply to chronic hepatitis C (CHC)? The review considers this question with implications for the immune status and functionality of the immune system of a chronically HCV-infected host. The data collected here indicate that CHC may increase the risk of viral superinfections and modify their course by immunocompromising the host. Patients with CHC do not lose the 'memory' of previous infections and vaccinations but, apparently, have problems with building such immunity anew, as illustrated by their impaired response to hepatitis A and B vaccinations. This underlines the necessity of extra protection of CHC patients against blood-borne diseases, hepatitis A, possibly also varicella, influenza, tetanus, and diphtheria - immunity to which, in the Western population, appears to falter. Such immune protection has to be adapted to selective impairments of immune response characteristic to CHC. Some approaches to this are reviewed here and more need to be elaborated. Special attention has to be given to CHC patients who do not respond to common vaccines; further studies in this field are of great interest.

[Is GB virus C alias "hepatitis" G virus involved in human pathology?]

GB virus-C alias "hepatitis" virus G was discovered in 1995 as a putative causative virus of non A-E hepatitis. It is a very common virus found in 1 to 5% of eligible blood donors in developed countries. Numerous studies over seven years led to the exclusion of its role as a significant etiological agent of hepatitis. Its in vivo replication site is still unknown. Its direct involvement in the induction of significant hepatic or extra-hepatic diseases could not be demonstrated. However, coinfections with other viruses may contribute to changes in the evolution of both liver disease (negatively) and HIV/AIDS (favourably). Today, no country has decided to screen GBV-C in blood donors. However, more studies are necessary before the absence of influence of GBV-C infection on human health in the context of other viral infections could be confirmed definitely. This article is a review of the literature on a possible involvement of GBV-C in pathologies whether associated or not to other infections.

GB virus C/hepatitis G virus infection in patients investigated for chronic liver disease and in the general population in southern Sweden

Serum samples from patients referred for liver biopsy for investigation of suspected chronic liver disease (n = 286) and from healthy middle-aged volunteers (n = 445) were analyzed for markers of exposure to GB virus C/hepatitis G virus (GBV-C/HGV), hepatitis B virus and hepatitis C virus. GBV-C/HGV analyses included GBV-C/HGV PCR for detection of viremia and GBV-C/HGV enzyme-linked immunosorbent assay for anti-GBV-C/HGV E2 antibodies. Liver biopsies were re-evaluated by a hepatopathologist. GBV-C/HGV markers were detected in 97/286 (34%) patients (GBV-C/HGV RNA = 26; anti-GBV-C/HGV E2 antibodies = 74) compared to 86/445 (19%; p < 0.0001) controls (GBV-C/HGV RNA = 7, anti-GBB-C/HGV E2 antibodies = 79). A significantly higher proportion of GBV-C/HGV-exposed subjects in the patient group were viremic compared to controls (27% vs. 8.1%; p = 0.0015). GBV-C/HGV markers were more commonly found in patients with chronic hepatitis B and C. In patients with GBV-C/HGV viremia, a higher occurrence of bile duct degeneration was detected than in non-viremic patients. Markers of GBV-C/HGV infection were over-represented among patients investigated for chronic liver disease, and ongoing GBV-C/HGV viremia was more common in this group than in controls. Apart from a higher prevalence of bile duct degeneration in viremic patients, infection with GBV-C/HGV did not confer any specific histological characteristics.

Are hepatitis G virus and TT virus involved in cryptogenic chronic liver disease?

BACKGROUND

Hepatitis G virus can cause chronic infection in man but the role of this agent in chronic liver disease is poorly understood. Little is known about the relation of another newly discovered agent, the TT virus, with chronic liver disease.

AIM

To investigate the rate of infection with hepatitis G virus and TT virus in patients with cryptogenic chronic liver disease.

PATIENTS

A total of 23 subjects with chronically raised alanine transaminase and a liver biopsy in whom all known causes of liver disease had been excluded, and 40 subjects with hepatitis C virus-related chronic liver disease.

METHODS

Evaluation of anti-hepatitis G virus by enzyme immunoassay. Hepatitis G virus-RNA by polymerase chain reaction with primers from the 5' NC and NS5a regions. TT virus-DNA by nested polymerase chain reaction with primers from the ORF1 region. Results. Hepatitis G virus-RNA was detected in 4 out of 23 patients with cryptogenic chronic hepatitis and in 6 out of 40 with hepatitis C virus chronic hepatitis (17.4% vs 15% p=ns). At least one marker of hepatitis G virus infection (hepatitis G virus-RNA and/or anti-hepatitis G virus, mostly mutually exclusive) was present in 6 out of 23 patients with cryptogenic hepatitis and 16 out of 40 with hepatitis C virus liver disease (26. 1% vs 40% p=ns). T virus-DNA was present in serum in 3 subjects, 1 with cryptogenic and 2 with hepatitis C virus-related chronic liver disease. Demographic and clinical features, including stage and grade of liver histology, were comparable between hepatitis G virus-infected and uninfected subjects. Severe liver damage [chronic hepatitis with fibrosis or cirrhosis) were significantly more frequent in subjects with hepatitis C virus liver disease.

CONCLUSIONS

In Southern Italy, hepatitis G virus infection is widespread among patients with chronic hepatitis, independently of parenteral risk factors. Its frequency in subjects with cryptogenic liver disease parallels that observed in hepatitis C virus chronic liver disease, thus ruling out an aetiologic role of hepatitis G virus. TT virus infection is uncommon in patients with cryptogenic or hepatitis C virus-related liver disease who do not have a history of parenteral exposure.

Liver inflammatory cells, apoptosis, regeneration and stellate cell activation in non-alcoholic steatohepatitis

BACKGROUND

The pathogenesis of non-alcoholic steatohepatitis remains unclear from several points of view. Minimal diagnostic criteria are still not defined.

AIM

To gather information useful for diagnosis and to improve the understanding of pathogenic mechanisms.

PATIENTS

A series of 14 patients with non-alcoholic steatohepatitis, identified among liver outpatients, were paired for age, sex and alanine amino transferase values with 14 patients with hepatitis C virus infection without steatosis.

METHODS

Clinical, biochemical and immunohistological examination, including characterisation of inflammatory cell population, evaluation of type III collagen and tenascin deposition, activation of stellate cells, hepatocellular apoptosis and proliferation.

RESULTS

Patients with non-alcoholic steatohepatitis were more frequently obese, had higher triglyceride concentrations and lower gamma-globulins. T lymphocytes outnumbered polymorphonuclear cells, both in hepatitis C and in steatohepatitis, with a larger number of CD8 lymphocytes in patients with viral hepatitis but a comparable number of granulocytes. This resulted in a higher granulocytes to T cells ratio in steatohepatitis, possibly making these cells more easily detectable in spite of similar absolute numbers. Portal fibrosis and piecemeal necrosis were prevalent in hepatitis C virus infection, pericentral fibrosis was similar Hepatocellular apoptosis and proliferation as well as stellate cell activation were less relevant in steatohepatitis than in hepatitis C virus infection in spite of similar alanine amino transferase levels.

CONCLUSIONS

These data provide a possible explanation for the relatively low tendency to progression of non-alcoholic steatohepatitis in most patients despite increased alanine amino transferase and suggest that non-death-related release of alanine amino transferase might occur in non-alcoholic steatohepatitis. This makes liver biopsy an essential part of the clinical setting supporting diagnosis, evaluation of severity and possibly definition of the evolutionary trend.

High frequencies of HGV and TTV infections in blood donors in Hangzhou

AIM: To determine the frequencies of HGV and TTV infections in blood donors in Hangzhou.

METHODS: RT-nested PCR for HGV RNA detection and semi-nested PCR for TTV DNA detection in the sera from 203 blood donors, and nucleotide sequence analysis were performed.

RESULTS: Thirty-two (15.8%) and 30 (14.8%) of the 203 serum samples were positive for HGV RNA and TTV DNA, respectively. And 5 (2.5%) of the 203 serum samples were detectable for both HGV RNA and TTV DNA. Homology of the nucleotide sequences of HGV RT-nested PCR products and TTV semi-nested PCR products from 3 serum samples compared with the reported HGV and TTV sequences was 89.36%, 87.94%, 88.65% and 63.51%, 65.77% and 67.12%, respectively.

CONCLUSION: The infection rates of HGV and/or TTV in blood donors are relatively high, and to establish HGV and TTV examinations to screen blood donors is needed for transfusion security. The genomic heterogeneity of TTV or HGV is present in the isolates from different areas.

GB virus C/hepatitis G virus (GBV-C/HGV): still looking for a disease

GB Virus C and Hepatitis G Virus (GBV-C/HGV) are positive, single-stranded flaviviruses. GBV-C and HGV are independent isolates of the same virus. Transmission via the blood-borne route is the commonest mode, although vertical and sexual transmission is well documented. GBV-C/HGV is distributed globally; its prevalence in the general population is 10 fold higher in African countries than in non-African countries. High prevalences of GBV-C/HGV have been found in subjects with frequent parenteral exposure and in groups at high risk of exposure to blood and blood products. The clinical significance of human infection with GBV-C/HGV is currently unclear. The virus can establish both acute and chronic infection and appears to be sensitive to interferon. Only some 12-15% of chronic Non-A, B, C hepatitis cases are infected with GBV-C/HGV. A direct association with liver pathology is still lacking and it is not yet clear as to whether GBV-C/HGV is indeed a hepatotropic virus. Current evidence suggests that the spectrum of association of GBV-C/HGV infection with extrahepatic diseases ranges from haematalogical diseases, aplastic anaemia, human immunodeficiency virus (HIV)-positive idiopathic thrombocytopenia and thalassemia, through to common variable immune deficiency and cryoglobunemia.

A high frequency of GBV-C/HGV coinfection in hepatitis C patients in Germany

AIM: To detect infection rate of GBV-C/HGV in hepatitis C patients, to determine the methods of higher sensitivity and the primers of higher efficiency for GBV-C/HGV RNA detection and to study the dominant subtype and mutation of GBV-C/HGV.

METHODS: Quantitative RT-PCR for detection pf HCV RNA concentration in serum samples, RT-nested PCR with two sets of primers for detection of GBV-CRNA, RT-PCR ELISA with two sets of primers for detection of HGV RNA, nucleotide sequence and putative amino acid sequence analysis.

RESULTS: The positive rates of GBV-C RNA at the 5’-NCR and NS3 region in 211 serums amples from the patients with HCV infection were 31.8% and 22.8% respectively. The positive rates of HGV RNA at the 5’-NCR and NS5 region in the same samples were 47.9% and 31.8% respectively. The total positive rate of GBV-C/HGV RNA was as high as 55.5%. HCV copy numbers in the patients without GBV-C/HGV coinfection were statistically higher than that in the patients with GBV-C/HGV coinfection (P < 0.01). Frequent mutation of nucleotide residue was present in the amplification products. Frameshift mutation was found in two samples with GBV-C NS3 region nucleotide sequences. All nucleotide sequences from amplification products showed higher homology to HGV genome than to GBV-C genome even though part of the sequences were amplified with GBV-C primers.

CONCLUSION: A high frequency of GBV-C/HGV coinfection existed in the hepatitis C patients. RT-PCR ELISA was more sensitive than RT-nested PCR for detection of GBV-C/HGV RNA. The primers derived from the 5’-NCR was more efficient than those derived from the NS3 and NS5 regions. A reverse relationship was found to exist between HCV RNA concentration and GBV-C/HGV infection frequency. HGV was the dominant subtype of the virus in the local area. The major mutations of GBV-C/HGV genomes were random mutation of nucleotide residue.

Leptin has no role in determining severity of steatosis and fibrosis in patients with chronic hepatitis C

OBJECTIVE

The presence of steatosis is a common histological finding in patients with chronic hepatitis C (CHC). The causes of the severity of this condition are not yet clear, although both metabolic and viral factors supposedly are involved. In this study our aim was to examine the possible influence that leptin levels, hepatitis C virus (HCV) RNA levels, and hepatitis G virus (HGV) infection have on the severity of steatosis and on the presence and degree of fibrosis in patients with CHC.

METHODS

One hundred eighty-two CHC patients with histological findings of steatosis were chosen from among a cohort of patients referred to our center for staging of liver disease. Among them 48 CHC patients were accurately selected so as to rule out possible confounding factors for the presence of steatosis (diabetes mellitus, hyperlipemia, obesity, alcohol). Leptin levels, HCV RNA levels, and HCV genotype, and the presence of HGV RNA were assessed in these patients and related to histological findings.

RESULTS

We found that leptin levels in CHC patients were similar to those in healthy subjects. No relationship was found between leptin levels and severity of steatosis. HCV RNA levels, HCV genotype, and the presence of HGV infection were no different among CHC patients with various degrees of steatosis. Leptin was not related to different degrees of fibrosis, whereas higher viral load was the only parameter associated to higher fibrosis scores.

CONCLUSIONS

These findings suggest that the degree of steatosis in patients with CHC does not seem to depend on serum leptin levels or on viral factors, at least as far as HCV viremia and genotype and HGV infection are concerned. The severity of fibrosis does not seem to be influenced by leptin levels, whereas HCV viral load does seem to play some role.

GB virus C/hepatitis G virus replicates in human haematopoietic cells and vascular endothelial cells

A novel flavivirus, GB virus C (GBV-C)/hepatitis G virus (HGV), has been detected in chronic liver disease patients. It is known that the viral RNA can be detected in ∼5% of American blood donors. However, the implications for liver disease and the sites of virus replication remain unknown. Possible sites of virus replication were studied by using cell lines and/or primary cells derived from human lymphoid cells, myeloid cells, hepatocytes and endothelial cells. RNA was detected by virus strand-specific RT–PCR and GBV-C/HGV antigen was detected with a rabbit polyclonal anti-E2 (envelope 2) antibody by Western blot analysis. Negative-strand RNA, representative of replicating virus, was detected in lymphoid and megakaryocytoid cell lines and primary vascular endothelial cells. In addition, an increase in virus titre over time was demonstrated and viral antigen was detected, and virus could be passaged to infect fresh cells. However, viral RNA or antigen could not be detected in any of the hepatocyte lines tested. These results indicate that the replication site of GBV-C/HGV is not primarily in hepatocytes and that detection of replicating virus in hepatic tissue may reflect virus replication in haematopoietic cells and/or vascular endothelial cells present in the liver.

GB virus C/hepatitis G virus (GBV-C/HGV): still looking for a disease

GB Virus C and Hepatitis G Virus (GBV-C/HGV) are positive, single-stranded flaviviruses. GBV-C and HGV are independent isolates of the same virus. Transmission via the blood-borne route is the commonest mode, although vertical and sexual transmission is well documented. GBV-C/HGV is distributed globally; its prevalence in the general population is 10 fold higher in African countries than in non-African countries. High prevalences of GBV-C/HGV have been found in subjects with frequent parenteral exposure and in groups at high risk of exposure to blood and blood products. The clinical significance of human infection with GBV-C/HGV is currently unclear. The virus can establish both acute and chronic infection and appears to be sensitive to interferon. Only some 12-15% of chronic Non-A, B, C hepatitis cases are infected with GBV-C/HGV. A direct association with liver pathology is still lacking and it is not yet clear as to whether GBV-C/HGV is indeed a hepatotropic virus. Current evidence suggests that the spectrum of association of GBV-C/HGV infection with extrahepatic diseases ranges from haematalogical diseases, aplastic anaemia, human immunodeficiency virus (HIV)-positive idiopathic thrombocytopenia and thalassemia, through to common variable immune deficiency and cryoglobunemia.

Hepatocyte steatosis is a cytopathic effect of hepatitis C virus genotype 3

BACKGROUND/AIMS

Patients infected with the hepatitis C virus (HCV) often have liver steatosis, suggesting the possibility of a viral cytopathic effect. The aim of this study was to correlate the occurrence and severity of liver steatosis with HCV RNA type, level and sequence of the core-encoding region.

METHODS

We scored the liver steatosis in 101 HCV-infected individuals carefully selected to exclude other risk factors of a fatty liver. Results were compared with HCV RNA genotype and level in serum and liver. In selected patients, we assessed the effect of antiviral therapy on steatosis and the relationship between nucleocapsid sequence heterogeneity and fat infiltration.

RESULTS

Steatosis was found in 41 (40.6%) patients, irrespective of sex, age or route of infection. HCV genotype 3 was associated with higher steatosis scores than other genotypes. A significant correlation between steatosis score and titer of intrahepatic HCV RNA was found in patients infected with genotype 3, but not in those infected with genotype 1. In selected patients, response to alpha-interferon was associated with the disappearance of steatosis. Analysis of the nucleocapsid of 14 HCV isolates failed to identify a sequence specifically associated with the development of steatosis.

CONCLUSIONS

We provide virological and clinical evidence that the steatosis of the liver is the morphological expression of a viral cytopathic effect in patients infected with HCV genotype 3. At variance with published evidence from experimental models, the HCV nucleocapsid protein does not seem to fully explain the lipid accumulation in these patients.

Mother-to-infant transmission of GB virus type C/HGV

BACKGROUND

The potentially hepatotropic flavivirus-like virus, GB virus type C (GBV-C)/HGV, has been detected in a few patients with acute and chronic hepatitis and in a certain proportion of blood donors and recipients of blood or blood components.

STUDY DESIGN AND METHODS

Sera from 2979 pregnant Japanese women were examined for the presence of GBV-C/HGV RNA by nested RT-PCR. Mothers who were positive for viral RNA and their 34 infants were followed and tested for infection.

RESULTS

Of the 2979 women, 32 (1.1%) were positive for GBV-C/HGV RNA. Twenty-six (76.5%) of 34 babies born to these women were positive for the virus when first tested. A significantly higher titer of viral RNA was observed in mothers whose infants were infected than in those whose infants were uninfected (mean +/- SD, 10(6.3 +/- 0.9) vs. 10(4.6 +/- 0.9)/mL; p<0.001). Twenty-three (96%) of 24 babies born to mothers whose serum viral titers were 10(6) mL or more were infected with the virus. Infants delivered by elective caesarean section had a lower risk (OR, 0.13; 95% CI, 0.02-0.82) than those delivered vaginally or by emergency caesarean section. No other risk factors for mother-to-infant transmission were confirmed.

CONCLUSIONS

GBV-C/HGV is frequently transmitted from mothers to infants in the general population. The most critical factor is the titer of viral RNA in the maternal serum. By the use of elective caesarean section in women with high titers of viral RNA, vertical transmission of the virus may be lessened.

[Coinfection with hepatitis G virus in chronic hepatitis C. Response to treatment with interferon alpha]

BACKGROUND

It is thought that the cytopathic effect of HGV is not important. Nevertheless, the cytopathic effect on liver is less known in the cases of co-infection with HCV. The aim was to study the prevalence of co-infection in patients with chronic hepatitis C (CHC) and to analyse the clinical-epidemiological and histological data and the interferon (IFN) response.

PATIENTS AND METHODS

We included 180 patients with CHC and the HGV-RNA was determined.

RESULTS

The prevalence of co-infection was 12.2% (n = 22). No statistical differences were observed between the non co-infected and co-infected groups with regard to the age, sex, mechanism of transmission and alcohol abuse. Also, there were no differences in the hepatic biochemical, no organ-specific antibodies, histological lesions and Knodell index. The HCV biochemical response (BR) and virological response (VR) after 6 months post-IFN were the same in both groups (HGV negative: BR = 29%, VR = 12%; HGV positive: BR = 22%, VR = 18%). HGV was determined after 6 months posttreatment in the co-infected group (first cycle of IFN, n = 22; second cycle of IFN, n = 9): 12 (55%) were HGV-RNA negative and 5 (23%) HCV-RNA negative, (p = 0.021). When we compared the BR vs VR in this group, there were 12 HGV-RNA negative but only two had BR (NS). On the contrary, the BR was related to HCV-RNA negative (p = 0.023).

CONCLUSION

The prevalence of HGV co-infection is important in our area (12.8%). The HGV does not increase the pathogenicity of HCV and does not change the IFN response, although the HGV is more IFN sensible than HCV. The determination of HGV is not necessary in patients with HCV.

Sequence diversity in the 5'-UTR region of GB virus C/hepatitis G virus assessed using sequencing, heteroduplex mobility analysis and single-strand conformation polymorphism

GB virus C/hepatitis G virus (GBV-C/HGV) is a positive-sense RNA virus belonging to the Flaviviridae family identified recently. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect GBV-C/HGV RNA using nested primers designed to amplify 245 bp of the 5'-untranslated region (UTR). GBV-C/HGV RNA was detected in 20.7% of 101 HCV-RNA positive and 6.8% of 44 HCV-RNA negative specimens. Sequencing of the PCR products demonstrated they had between 84.3 and 100% nucleotide identity. Most of the diversity corresponded to two variable regions identified within the 5'-UTR. Phylogenetic analysis indicated that GBV-C/HGV subtypes present in Australia belonged to group 2 and were closest in evolutionary terms to isolates from the USA and Europe. All isolates were analysed using single-strand conformation polymorphism (SSCP) and heteroduplex mobility analysis (HMA) on 8% non-denaturing polyacrylamide gels. SSCP of the isolates identified a number of distinct conformation polymorphisms that corresponded with sequence-determined genetic diversity. HMA was developed to assess the amount of genetic diversity between isolates without the need for sequencing. The average difference between the predicted divergence of two isolates calculated from the mobility of the heteroduplex and the actual value (based on nucleotide sequence) was 2.3% in this sample of isolates, where the mean sequence divergence was 8.52%.

Hepatitis G virus: molecular organization, methods of detection, prevalence, and disease association

This article reviews data on hepatitis G virus (HGV) prevalence and possible disease associations in various groups of patients. An important fraction of acute or chronic hepatitis cases probably have a viral etiology and are not attributable to known hepatitis viruses. Therefore, researchers continually are looking for new hepatitis viruses. Among the agents found are members of GB hepatitis viruses, including GB-C virus, or HGV. This review presents the history of the discovery of HGV, its molecular biology and some methods of detection; results of clinical and molecular studies of HGV infection also are discussed.

Influence of transfusion-transmitted virus infection on the clinical features and response to interferon therapy in Japanese patients with chronic hepatitis C

Recently, the genome of a novel DNA virus, transfusion-transmitted virus (TTV), was cloned from the plasma of a blood donor who had an elevated aminotransferase level but no serological markers of known hepatitis viruses. In this study, we investigated the influence of TTV infection on the clinical features and response to interferon (IFN) therapy in patients with chronic hepatitis C. We studied 247 patients who had received a 16- or a 24-week course of IFN-alpha therapy. The serum of these patients was analysed for TTV DNA using a hemi-nested polymerase chain reaction and TTV was detected in 114 patients (46%). No significant differences were found with respect to clinical features (gender, age, liver-related biochemical tests, hepatitis C virus (HCV) genotype and serum HCV RNA levels) between the patients who were positive for TTV DNA and those who were negative for TTV DNA. The fibrosis score was higher in TTV-positive patients (2.1 +/- 1.1) than in TTV-negative patients (1.7 +/- 1.1, P = 0.023). The biochemical sustained-response rate was 25% in TTV-positive patients and 25% in TTV-negative patients (not significant). A sustained HCV clearance rate was achieved in 26% of TTV-positive patients and in 22% of TTV-negative patients (not significant). TTV DNA clearance after IFN therapy was observed in 36 of 69 patients (52%) for whom stored serum samples were available. The disappearance of TTV DNA had no effect on the biochemical response to IFN therapy. In conclusion, TTV co-infection is frequently observed in Japanese patients with chronic hepatitis C. In chronic hepatitis C, TTV does not modify the clinical features or the response to IFN.

Prevalence of GBV-C/HGV-RNA, virus genotypes, and anti-E2 antibodies in autoimmune hepatitis

OBJECTIVE

We investigated the prevalence of hepatitis G-RNA (GBV-C/HGV-RNA), a recently cloned new flavivirus, and of antibodies to the envelope 2 antigen (anti-E2), a marker of past infection, in patients with autoimmune hepatitis, and compared it with the prevalence in patients with chronic viral hepatitis and healthy control individuals.

METHODS

Sera of 63 patients with autoimmune hepatitis were studied for the presence of GBV-C/HGV-RNA by reverse-transcription polymerase chain reaction and for anti-E2 by enzyme-linked immunosorbent assay. GBV-C/HGV genotypes were determined by genome sequencing.

RESULTS

Patients with autoimmune hepatitis had a similar high prevalence of GBV-C/HGV-RNA and anti-E2 antibodies as patients with chronic viral hepatitis B or C. GBV-C/HGV-RNA was found significantly more often in patients with autoimmune hepatitis (11%, p = 0.045), hepatitis B (16%, p = 0.004), or hepatitis C (21%, p = 0.001) than in healthy controls (2%). The prevalence of anti-E2 antibodies in patients with autoimmune hepatitis was not different from healthy controls (17% vs 13%, NS). The various subtypes of autoimmune hepatitis had similar prevalence rates of GBV-C/HGV-RNA as patients with liver-kidney microsomal antibody-positive hepatitis C. All of our anti-E2+ (GBV-C/HGV-RNA-) patients were positive for anti-smooth-muscle antibody, whereas only 29% of GBV-C/HGV-RNA+ (anti-E2-) patients were positive (p = 0.025). All seven of the GBV-C/HGV-RNA+ patients with autoimmune hepatitis had genotype 2a, which is also the most prevalent genotype in our region.

CONCLUSION

The prevalence of GBV-C/HGV-RNA is significantly increased in patients with autoimmune hepatitis, compared with healthy controls, and is similar to the increased prevalence seen in chronic hepatitis B or C patients. Anti-E2 positivity was associated with antibodies against smooth-muscle antigen in all cases. All GBV-C/HGV+ autoimmune hepatitis patients were infected with genotype 2a.

Pathogenicity of GBV-C/HGV infection

Extensive studies of GBV-C/HGV in acute and chronic hepatitis non-A-non-E have failed to provide hard evidence for a major role in this disease. Persistent GBV-C/HGV viraemia is in most cases associated with normal ALT levels, and only in a minority of patients are mild elevations of aminotransferases found. Its disease-inducing capacity is questionable and the findings accumulated so far are best explained by looking at GBV-C/HGV as a well-adapted, predominantly parenterally transmitted, persistent virus; it might be transmitted concomitantly with another, still unidentified hepatitis non-A-non-E virus. This does not exclude the possibility that GBV-C/HGV might, in some rare cases and under certain circumstances, induce a hepatitis-like illness as seen with other viruses such as EBV or CMV. GBV-C/HGV definitely plays a minor role only, if any, in post-transfusion and community-acquired hepatitis non-A-non-E.

The hepatic flaviviridae: summary

Hepatitis C envelope proteins (E1, E2) induce protective neutralizing antibodies. The extent of sequence diversity reflects the host's ability to control viral populations and the response to antiviral therapy. Attempts to prepare effective vaccines against HCV are foiled by lack of prolonged protective immunity. Plasmid vaccines and the use of uninfectious virus-like particles are being developed. HCV induces a cellular humoral immune response, but this is inadequate to clear the virus and the disease becomes chronic. In any patient, the natural history of HCV infection depends on the age when infected, and the presence of other diseases. The transfusion-related disease has a worse prognosis than that transmitted by syringes and needles. The outlook in 'healthy blood donors' is uncertain. Interferon therapy for 3 or preferably 6 months results in a sustained response in about 30% of patients. Negative serum HCV RNA and normal AST values after 3 months of therapy indicates that there may be a sustained response. Whether or not to stop treatment at that time if HCV is still positive remains a matter of debate. The role of interferon treatment in preventing progression to cirrhosis and hepatocellular cancer is still uncertain. Ribavirin therapy alone reduces transaminases and hepatic histology improves. Improved results follow the combination of ribavirin with interferon. Ribavirin may have immuno-modularity and anti-inflammatory actions. Hepatitis G virus (HGV) is unlikely to play a significant role in liver disease in man.

The clinical significance of simultaneous infection with hepatitis G virus in patients with chronic hepatitis C

OBJECTIVES

Hepatitis G virus (HGV) is a recently discovered member of the flavivirus family that has been associated with acute and chronic hepatitis. HGV infection has been reported to coexist in 10-20% of patients with chronic hepatitis C. The significance of simultaneous infection with HGV and hepatitis C virus (HCV) remains to be clarified, as do the effects on HGV of therapeutic interventions such as interferon treatment or liver transplantation.

THE AIMS OF OUR STUDY WERE

1) to examine the frequency of HGV infection in the settings of liver transplantation and interferon therapy for hepatitis C; and 2) to compare HGV RNA levels before and after liver transplantation or interferon treatment.

METHODS

Pre-treatment sera were available in 65 patients with chronic hepatitis C treated with interferon; pretransplant sera were available in 49 patients transplanted for end stage liver disease associated with chronic hepatitis C. Information collected included age, sex, risk factors for hepatitis, concurrent liver disease, patient and allograft survival, biochemical response to interferon, histological activity index, and degree of fibrosis/cirrhosis. HCV genotyping was performed by sequencing the NS-5 region. HGV quantitation was performed using a research-based branched DNA (bDNA) assay with a set of probes directed at the 5' untranslated region.

RESULTS

HGV was detected in 10 of 49 patients (20%) before transplant and in 13 of 65 patients (20%) treated with interferon. There was a female predominance among HGV-positive compared with HGV-negative transplant patients (80% vs 20%; p < 0.01), but such a difference was not observed in the interferon-treated group. Hepatic iron concentration was lower in hepatic explants from patients who were HGV-positive than in those who were HGV-negative (318 +/- 145 microg/g dry weight vs 1497 +/- 2202 microg/g dry weight; p = 0.02). HCV exposure after 1980 was more common in the HGV-positive patients than in those who were HGV-negative for the entire study population (10 of 20 [50%] vs 16 of 66 [24%]; p = 0.03), as well as for the nontransplant subgroup (8 of 12 [67%] vs 12 of 39 [31%]; p = 0.03). HGV RNA levels declined at 1 yr after transplant in seven of eight patients. Among nine patients tested during or after interferon treatment, HGV RNA levels declined from pretreatment levels in all and disappeared in three.

CONCLUSIONS

Among patients with chronic hepatitis C treated with either interferon or liver transplantation, the frequency of coinfection with HGV is about 20%. HGV may be a more recent virus in the US than HCV. Coinfection with HGV does not appear to affect the likelihood of response to interferon in patients with hepatitis C. Finally, HGV RNA levels appear to decline after both liver transplantation and interferon therapy, suggesting possible suppression by increased HCV replication in the former case, and a possible drug treatment effect in the latter.

Hepatitis G virus infection in a high-risk subgroup of hospitalized dental patients

OBJECTIVE

The prevalence of hepatitis G virus infection was evaluated in dental patients whose clinical laboratory test results were positive for hepatitis C virus antibody, hepatitis B virus surface antigen, or elevated serum alanine transaminase concentrations.

STUDY DESIGN

Frozen serum samples from patients with hepatitis C virus antibody (n = 63), hepatitis B virus surface antigen (n = 20), or alanine transaminase concentrations greater than 100 IU (n = 14) were assessed for GB virus C (GBV-C)/hepatitis G virus RNA by a reverse transcriptase-polymerase chain reaction.

RESULTS

Six of 63 patients with hepatitis C virus antibodies had serum hepatitis G virus RNA (9.5%), and 2 of 20 subjects with hepatitis B virus surface antigen had hepatitis G virus RNA (10.0%). None of 14 patients whose alanine transaminase concentration was greater than 100 IU/L had hepatitis G virus RNA. Of 4 subjects with both hepatitis C virus antibody and hepatitis B virus surface antigen, 2 had hepatitis G virus RNA (50%). In the total study population (N = 92), 6 subjects (6.5%) had hepatitis G virus RNA. All hepatitis G virus-infected patients also had hepatitis C virus antibody. Neither serum alanine transaminase nor aspartate transaminase concentrations were different between subjects with and subjects without hepatitis G virus RNA. The lack of a relationship between hepatitis G virus infection and elevation of alanine transaminase and aspartate transaminase might suggest that this virus is not truly a hepatitis virus.

CONCLUSIONS

Hospitalized dental patients are infected with hepatitis G virus at a prevalence similar to or slightly higher than that seen in the general population. Dentists should pay close attention to infection control with respect to the potential new hepatitis virus known as hepatitis G virus.

Correlation of interferon treatment response with GBV-C/HGV genomic RNA and anti-envelope 2 protein antibody

The clinical significance of GB virus C/hepatitis G virus (GBV-C/HGV) co-infection was studied retrospectively in 100 consecutive patients with hepatitis C virus (HCV) infection. All 100 patients had been treated with interferon-alpha (IFN-alpha). Co-infection with GBV-C/HGV and HCV was detected in 10 of the 100 patients (10%) and anti-envelope 2 region (anti-E2) antibody was detected in 25 patients. None of the patients with GBV-C/HGV RNA had anti-E2 antibody. Co-infected patients were younger (P < .005) and their serum transaminase levels were lower than HCV-only infected patients (P< .01). In 7 of the 10 co-infected patients, HCV RNA was eradicated from serum after IFN-alpha treatment and normal alanine transaminase (ALT) levels continued in 6 of these 7 patients. In one patient who was negative for HCV RNA but positive for GBV-C/HGV RNA, the ALT level relapsed transiently. The rate of clearance of HCV and normalization of the ALT level was significantly higher in co-infected patients than in HCV-only infected patients (P < .05). GBV-C/HGV RNA disappeared from 6 of the 10 co-infected patients (60%) upon cessation of IFN-alpha treatment. However, continuous clearance of GBV-C/HGV was observed in only two patients and anti-E2 antibody could not be detected in the serum of these patients. These results indicate that co-infected patients tend to be younger and more sensitive to IFN-alpha treatment. However, long-term clearance of GBV-C/HGV after IFN-alpha treatment may be difficult. Moreover, anti-E2 antibody may act to neutralize GBV-C/ HGV.

Prevalence, implication, and viral nucleotide sequence analysis of GB virus-C/hepatitis G virus infection in acute fulminant and nonfulminant hepatitis

The clinical impact of GB virus-C (GBV-C)/hepatitis G virus (HGV) infection on various causes of acute hepatitis and fulminant hepatitis is controversial. In this study, serum samples from 164 patients with acute hepatitis of various causes, 34 asymptomatic hepatitis B virus (HBV) carriers, and 34 healthy adults were tested for GBV-C/HGV RNA by reverse transcription-nested polymerase chain reaction using primers based on the 5'-untranslated region. Nucleotide sequences of GBV-C/HGV RNA from various groups were compared. The prevalence of GBV-C/HGV RNA was significantly higher in patients with acute hepatitis D virus (HDV) superinfection than in HBV carriers or healthy controls (10/37 vs. 2/34, P < 0.02; 10/37 vs. 1/34, P < 0.005). GBV-C/HGV RNA was detected in 11.1% of acute hepatitis A patients, 9.5% of acute hepatitis B patients, 15.8% of acute hepatitis C patients, 12.5% of acute hepatitis E patients, 11.8% of chronic hepatitis B patients with acute exacerbation, and 11.1% in patients with non-A to -E hepatitis; each was not significantly higher than that in HBV carriers or healthy adults. There were no significant differences in gender, age, serum albumin, bilirubin, and alanine aminotransferase levels nor in the occurrence of fulminant hepatitis (6/28 vs. 36/136) between patients with or without GBV-C/HGV RNA. All six patients with fulminant hepatitis who had GBV-C/HGV RNA were complicated by infection with hepatitis B, C, or D. The GBV-C/HGV clones from 21 patients with or without fulminant hepatitis belonged to group 3. No particular strain of GBV-C/HGV was associated with fulminant hepatitis.

Transfusion virology: progress and challenges

Discoveries of new human viruses and new technologies for their detection have made, and will continue to make, major contributions to the safety of blood transfusion. This article discusses the practical issues involved in the implementation of additional serological screening tests for viruses such as human T-lymphotropic virus, and reviews current information on the prevalence and pathogenicity of more recently discovered viruses, such as hepatitis G virus (HGV) or GB virus-C (GBV-C) and human herpes virus 8, a potential aetiological agent of Kaposi's sarcoma. Progress in the technology behind nucleic acid amplification techniques, such as the polymerase chain reaction (PCR), makes direct detection of viruses such as human immunodeficiency virus and hepatitis C virus possible. The use of such methods for screening will allow the earlier detection of acutely-infected individuals and the elimination of transmission from 'window' period donations before seroconversion for antibody. Establishing a framework for PCR-based screening would also enable the testing for others such as hepatitis A virus, parvovirus B19 and GBV-C/HGV for which serological detection methods cannot be or have not been developed.

HGV/GBV-C in liver tissue and in sera from patients with chronic hepatitis C

Forty-eight persons (M = 45, F = 3; age range = 20-53, mean = 32.2) affected with chronic hepatitis C were tested for HGV/GBV-C RNA and HCV-RNA by nested PCR and DEIA in serum and in liver specimens to evaluate the prevalence and the impact of HGV/GBV-C coinfection in patients with chronic HCV-related hepatitis. Sera were also assayed for antibodies to HGV/GBV-C E2 protein. Serum HGV/GBV-RNA could be detected in nine (19%) patients, and anti-E2 antibodies in 22 (46%) patients. The presence of HGV/GBV-C RNA or anti-E2 antibodies was mutually exclusive. The cumulative prevalence of HGV/GBV-C infection was 65% (31/48); the majority of these patients (26/31, 84%) were intravenous drug users (IVDUs). In eight of nine patients viraemic for HGV/GBV-C, RNA positivity could be revealed even in liver specimens; these eight patients were also positive for HCV-RNA both in serum and the liver and did not exhibit any specific association with HCV genotype. HGV/GBV-C RNA negative strand RT-PCR testing was negative in all of the eight liver specimens, providing little support to the hypothesis that liver represents the primary site of HGV/GBV-C replication. Moreover, patients with HGV/GBV-C and HCV coinfection were comparable to those with HCV infection alone in terms of biochemistry and liver histology.

HGV: the identification, biology and prevalence of an orphan virus

Hepatitis G virus (HGV) and GB virus C (GBV-C) (both hereinafter referred to as HGV) were independently identified in patients with hepatitis of unknown aetiology. HGV is a positive-sense RNA virus of the family Flaviviridae. The virus can establish both acute and chronic infection and appears to be sensitive to interferon. Horizontal transmission is mainly parenteral, although other routes such as vertical have been well documented. High risk groups include intravenous drug users (i.v.DUs), the multiply transfused, haemodialysis patients and haemophiliacs. Up to 90% of i.v.DUs are positive for either HGV-RNA or antibodies to HGV envelope-2 protein (anti-E2). HGV is frequently detected in patients with HBV and HCV infection. Its link to hepatitis has now become less certain. Only around 3-6% of non-A E hepatitis cases are HGV viraemic, clearly showing that HGV is not the major cause of idiopathic hepatitis as originally hoped. Around 1-5% of volunteer blood donors in developed countries are HGV viraemic, but the prevalence is 10-20% in the general population in some developing countries. At present, it is not known whether HGV is associated with other diseases in humans, is a passenger virus, or only becomes virulent under certain conditions.

The effect of treatment with alpha-interferon on hepatitis G/GBV-C viraemia. The CONSTRUCT Group

BACKGROUND

Hepatitis G virus (HGV) or GBV-C is frequently detected in patients co-infected with hepatitis C virus (HCV). This study investigated host and virologic factors influencing the response to HGV/GBV-C to alpha-interferon treatment.

METHODS

HGV/GBV-C was detected and quantified by nested polymerase chain reaction. The influence of variables such as liver biopsy appearance, liver function abnormalities, and response of HCV to interferon treatment was monitored.

RESULTS

Fourteen of the 25 HGV/GBV-C-infected patients treated with interferon (3-6 MIU three times a week for 6 months) became non-viraemic during treatment, although all relapsed after treatment withdrawal at 6 months, with no net change in virus load between 0 and 12 months.

CONCLUSIONS

Predictive factors for clearance of HGV/GBV-C viraemia by interferon were pre-treatment severity of liver disease (median Knodell score of 4, compared with 7 for non-responders; P = 0.030) and alanine aminotransferase levels (median, 114, 182 for non-responders; P = 0.039). Clearance was associated with the treatment response of HCV. Nine of 13 who cleared HGV/GBV-C also cleared HCV, compared with 3 of 11 HGV/GBV-C non-responders; P = 0.05). The shared susceptibility of HGV/GBV-C and HCV to interferon treatment suggests a link between the mechanism of clearance of the two viruses.

Influence of GB virus C viraemia on the clinical, virological and histological features of early hepatitis C-related hepatic disease

BACKGROUND/AIMS

GB virus C is a newly described RNA virus. The aims of this study were to determine the prevalence of GB virus C infection in patients with chronic type C hepatitis and to examine the clinical, virological and histological features in hepatitis C and GB virus C co-infected patients.

METHODS/RESULTS

One hundred and sixty patients with hepatitis C infection were studied. GBV-C RNA was detected in 33/160 (20.6%) patients; co-infected patients with hepatitis C and GB virus C infection were significantly younger (p=0.04). No difference was found between the two groups according to gender and biochemical parameters. Seventy-two of the 160 patients, for whom a liver tissue specimen taken simultaneously with the serum was available and who had compensated liver disease, were studied separately. The source of infection, duration of infection, HCV genotype and HCV RNA concentrations did not differ between 15/72 patients with dual infection and 57/72 with hepatitis C infection alone. Patients with co-infection had significantly higher degrees of portal and periportal inflammation (p=0.0006 and 0.01, respectively). No difference was observed in parenchymal activity score or extent of fibrosis.

CONCLUSIONS

These results indicate a relatively high prevalence of GB virus C infection in younger patients with chronic hepatitis C, suggesting a common route of transmission. Although GB virus C co-infection does not alter the biochemical and virological profile of patients with HCV hepatitis, there is an association between GB virus C and hepatitis C viraemia and portal and periportal inflammation.