Influence of hepatitis G virus infection on the severity of liver disease and response to interferon-alpha in patients with chronic hepatitis C

Human Pegivirus Type 1: A Common Human Virus That Is Beneficial in Immune-Mediated Disease?

Two groups identified a novel human flavivirus in the mid-1990s. One group named the virus hepatitis G virus (HGV) and the other named it GB Virus type C (GBV-C). Sequence analyses found these two isolates to be the same virus, and subsequent studies found that the virus does not cause hepatitis despite sharing genome organization with hepatitis C virus. Although HGV/GBV-C infection is common and may cause persistent infection in humans, the virus does not appear to directly cause any other known disease state. Thus, the virus was renamed “human pegivirus 1” (HPgV-1) for “persistent G” virus. HPgV-1 is found primarily in lymphocytes and not hepatocytes, and several studies found HPgV-1 infection associated with prolonged survival in people living with HIV. Co-infection of human lymphocytes with HPgV-1 and HIV inhibits HIV replication. Although three viral proteins directly inhibit HIV replication in vitro, the major effects of HPgV-1 leading to reduced HIV-related mortality appear to result from a global reduction in immune activation. HPgV-1 specifically interferes with T cell receptor signaling (TCR) by reducing proximal activation of the lymphocyte specific Src kinase LCK. Although TCR signaling is reduced, T cell activation is not abolished and with sufficient stimulus, T cell functions are enabled. Consequently, HPgV-1 is not associated with immune suppression. The HPgV-1 immunomodulatory effects are associated with beneficial outcomes in other diseases including Ebola virus infection and possibly graft-versus-host-disease following stem cell transplantation. Better understanding of HPgV-1 immune escape and mechanisms of inflammation may identify novel therapies for immune-based diseases.

Long-term maintenance of sustained virological response in liver transplant recipients treated for recurrent hepatitis C

BACKGROUND

The recurrence of hepatitis C viral infection is common after liver transplant, and achieving a sustained virological response to antiviral treatment is desirable for reducing the risk of graft loss and improving patients' survival.

AIM

To investigate the long-term maintenance of sustained virological response in liver transplant recipients with hepatitis C recurrence.

METHODS

436 Liver transplant recipients (74.1% genotype 1) who underwent combined antiviral therapy for hepatitis C recurrence were retrospectively evaluated.

RESULTS

The overall sustained virological response rate was 40% (173/436 patients), and the mean follow-up after liver transplantation was 11±3.5 years (range, 5-24). Patients with a sustained virological response demonstrated a 5-year survival rate of 97% and a 10-year survival rate of 93%; all but 6 (3%) patients remained hepatitis C virus RNA-negative during follow-up. Genotype non-1 (p=0.007), treatment duration >80% of the scheduled period (p=0.027), and early virological response (p=0.002), were associated with the maintenance of sustained virological response as indicated by univariate analysis. Early virological response was the only independent predictor of sustained virological response maintenance (p=0.008).

CONCLUSIONS

Sustained virological response achieved after combined antiviral treatment is maintained in liver transplant patients with recurrent hepatitis C and is associated with an excellent 5-year survival.

HGV-HCV/HBV co-infection in India: A pilot study

Background:

Hepatitis G virus (HGV) is newly identified virus, transmitted by infected blood and blood products. Effect of HGV infection on liver diseases is not well known.

Aims:

Co-infection of HGV with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection has been reported however; very limited data is available from India. Therefore, we have performed a pilot study for the presence of co-infection of HGV in chronic liver disease patients.

Setting and Design:

The study was performed in research laboratory at P.D. Hinduja National hospital and Medical research center, Mahim, Mumbai. Prospective study was designed.

Methods and Materials:

Forty HBV, HCV related chronic liver disease patients were studied. Forty randomly selected voluntary healthy blood donors visiting our blood bank were included as controls. Serum bilirubin, alanine aminotransferase (ALT), Aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were estimated. HGV infection was detected by using reverse transcriptase molony murine leukemia virus (M-MLV) with the help of HGV 340/625IC kit (Sacace, Italy).

Results and Conclusion:

One HCV positive patient had infection with HGV among 40 HBV/HCV chronic liver disease patients.

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

Profile of hepatitis A infection with atypical manifestations in children

We assessed the clinical course and biochemical profile of symptomatic children with viral hepatitis A who had atypical manifestations. Of 229 children with hepatitis A, atypical manifestations were found in 32 (14%) subjects. Prolonged cholestasis (n = 14), acute liver failure (9), relapse (9), ascites (8), and hematological problems (8) were the common presentations. Liver histology was suggestive of chronic liver disease in six children with protracted jaundice. Patients with atypical presentations were older (7.7 [1.6] years vs. 6.5 [2.6] years; p=0.012) and had higher total serum bilirubin (13.7 [8.1] mg/dL vs. 7.2 [4.0] mg/dL; p=<0.001) than those with typical presentation. Approximately 15% of children with acute hepatitis A infection have atypical presentation which is associated with increase in morbidity.

Hepatitis G virus infection in Egyptian children with chronic renal failure (single centre study)

BACKGROUND

Hepatitis G virus (HGV) is an RNA virus. It is mainly transmitted through exposure to contaminated blood although other routes may also exist. Patients with chronic renal failure (CRF) are at high risk of acquiring HGV because they require frequent blood transfusions. Ongoing HGV infection can be only diagnosed by demonstrating viremia in patient sample by reverse transcriptase (RT) PCR. Antibodies to the envelop protein E2 (anti E2) of HGV is an indicator of virus clearance and testify past HGV contact. This cross sectional study was done to assess the frequency of HGV exposure (ongoing and past infection) in Egyptian children with CRF and to study the possible risk factors of infection.

METHODS

This study included 100 children with CRF [34 on regular haemodialysis (HD) and 66 before the start of dialysis (predialysis)]. All patients sera were tested for HGV RNA by RT-PCR, anti E2, hepatitis C virus (HCV) antibody, hepatitis B surface antigen (HBsAg), and hepatitis B core antibody (HBcAB). Twenty five healthy children of matched age & sex were used as controls.

RESULTS

HGV RNA was positive in 9 (26.5%) of HD and 9 (13.6%) of predialysis children. Anti E2 was positive in 14 (41.2%) of HD and 19 (28.8%) of predialysis children.In comparison to controls; CRF (n = 100); HD and predialysis children had significantly higher prevalence of anti E2 [4% VS 33% for all CRF cases; (p = 0.002)& 41.2% (p = 0.002) and 28.8% (p = 0.01); for HD and predialysis groups; respectively]. HGV RNA was significantly more prevalent only in HD children in comparison to controls (p = 0.03). HD and predialysis children did not have significant difference in the prevalence of HGV RNA (p = 0.16) or anti E2 (p = 0.26).HGV exposure was not correlated with positivity of anti HCV (p = 0.32), HCV RNA (0.09), HBsAg/HBcAB (p = 1), age (p = 0.06), or gender (p = 0.83). It was significantly correlated with duration of the disease (p < 0.001). Ongoing HGV infection was significantly more prevalent with frequent blood transfusion (p < 0.001). There were no significant differences in serum levels of ALT (p = 0.09), total bilirubin (p = 0.1) and albumin (p = 0.06) in children with ongoing infection in comparison to healthy controls.

CONCLUSIONS

The frequency of HGV exposure in Egyptian children with CRF appears to be high and is mainly related to frequent blood transfusions and longer disease duration. HGV infection in these children is not associated with significant changes in hepatic biochemical parameters.

Hepatitis G virus infection in multitransfused Egyptian children

The purpose of this study was to identify the magnitude of the hepatitis G virus infection in 33 multitransfused cases and 20 matched controls. All were tested for liver biochemical profile, HBsAg, HCV-antibody, HGV-RNA, and antibody to envelop protein E(2). HGV was detected alone in 61% of the multitransfused cases and 15% of the controls. Hepatitis markers were negative in 21% of cases versus 70% of controls. HGV envelope antibody was detected in 12% of cases, and none of controls. Mean values of transaminases in HGV positives and negatives showed no significant differences. HGV infection is highly prevalent in Egyptian children with no impact in infected cases.

Hepatitis G virus exposure in dialysis staff

Hepatitis G virus (HGV) is a blood-borne virus. Some present data demonstrate an occupational risk of HGV infection in medical staff of dialysis units. The aim of this investigation was to assess the prevalence of HGV exposure in dialysis staff. This study was performed in a main dialysis unit in Iran. In 27 dialysis staff, HGV exposure was detected serologically by the presence of anti HGV envelope protein E2 (anti-E2) by an enzyme-linked immunosorbent assay, and compared with 77 hemodialysis (HD) and 13 continuous ambulatory peritoneal dialysis (CAPD) patients. All of them were also screened for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis C antibody (anti-HCV). A low prevalence of HGV exposure was found in the dialysis staff (0%), which nearly corresponded to the prevalence of the dialysis patients (HD 3.89%, CAPD 0%). The prevalence of anti-HCV and anti-HBs in staff was 37.03% and 33.33%, respectively, which was higher than HGV anti-E2. The prevalence of HGV exposure was low in dialysis staff in our study, and was near to the prevalence of HGV exposure in dialysis patients. Therefore, it can be concluded that the occupational risk for HGV exposure in our investigation was minimal.

Hepatitis G virus exposure in dialysis patients

BACKGROUND

Hepatitis G virus (HGV) is a blood-borne virus. The predominant route of its transmission is parenteral. The aim of this study was to assess the frequency of HGV exposure in haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients in Iran.

METHODS

This study was performed in a major dialysis centre in Tehran, Iran. The study cohort consisted of 77 patients on HD and 13 patients on CAPD. The presence of anti-HGV envelope protein E2 (anti-E2) in the blood serum, as determined by means of an ELISA assay, indicated HGV exposure. All patients were also screened for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs) and hepatitis C antibody (anti-HCV). In patients who tested positive for anti-E2, HGV RNA was detected by RT-PCR using primers derived from the NS5A region of the viral genome.

RESULTS

In total, 3.89% of the HD patients and none of the CAPD patients tested positive for anti-E2. None of the patients tested positive for HGV RNA. The mean age of the anti-E2-positive patients was 53.3 +/- 26.5 years, with 66.66% having previously received blood transfusion. The mean duration of dialysis of the anti-E2-positive patients was 68 +/- 64 months. Co-infection with HCV or HBV was not observed in the anti-E2 positive patients.

CONCLUSION

The rate of exposure to HGV was low among the dialysis patients in our study. The appearance of anti-E2 was accompanied by clearance of serum HGV-RNA. No relationship was noted between HGV exposure and age, sex, history of blood transfusion, time on dialysis and HCV or HBV markers.

[Hepatitis G virus and labile blood products: role of transfusional transmission]

The GBV-C/HGV (HGV) virus was discovered a few years ago. This virus is known to be parenterally as well as sexually transmitted. However, no study has found some pathogenic roles for HGV so far. In the present study, we aimed to investigate the transmission of HGV by blood components transfused to 284 patients hospitalized in surgery unit in 1995. We tested two parameters of infection in blood components transfused to infected recipients: viral RNA by PCR and anti-E2 antibodies by ELISA. We tried to suspect some potent hepatocyte impacts by assessing the levels of two enzymes in serums: alanine aminotransferase (ALT) and alpha-glutathion S-transferase (alpha-GST). We found that HGV-RNA was detectable in 3.6% of recipients prior to transfusion and 7.5% post-transfusion. For each infected recipient, we retrospectively did a search for HGV-RNA in each transfused blood component, and we found at least one blood component as HGV-RNA-positive for each transfusional infected recipient. Anti-E2 antibody prevalence standing for a former and cured infection was 39.6% in all the recipients. In viremic recipients, ALT levels were mostly normal, while alpha-GST levels were found more commonly elevated than in non-viremic recipients although non-significantly (20% vs. 6.3%; P = 0.07). The present study underlines that HGV transmission is mostly transfusional in surgery units, and that infectiosity of blood components can be anticipated by detection of the viral RNA by PCR. Furthermore, the possible relationship between the serum activity of alpha-GST and the hepatotropism of HGV, although non-admitted as pathogenic, should be investigated.

Evidence for probable sexual transmission of the hepatitis g virus

A cross-sectional epidemiology study evaluated the role of sexual activity and sexually transmitted diseases (STDs) in the transmission of hepatitis G virus (HGV/GBV-C) and other hepatitis virus infections in 944 subjects. There was a statistically significant higher prevalence of HGV/GBV-C, hepatitis B virus, and hepatitis C virus exposure in the STD clinic group (i.e., subjects who were currently seeking treatment for an STD) compared with the group who never had received treatment for an STD. In a comparison of the subjects with an STD versus those without an STD, the prevalence of HGV/GBV-C was 11.3% versus 4.9%, on the basis of polymerase chain reaction (PCR) results alone, and 36.6% versus 8.8%, when results of PCR and enzyme-linked immunosorbent assay were combined. Sexual activity and, possibly, the presence of an STD increases the risk of HGB/GBV-C transmission.

GB virus C/hepatitis G virus

GB virus C (GBV-C), or hepatitis G virus (HGV), is a recently discovered enveloped RNA virus belonging to the Flaviviridae family. GBV-C/HGV is transmitted by contaminated blood and/or blood products, intravenous drug use, from mother to child, sexually, and possibly through close social contacts. Several reports indicate a high prevalence of GBV-C/HGV viremia (1-4%) within healthy populations in Europe and North America, and an even higher prevalence (10-33%) among residents in South America and Africa. GBV-C/HGV has been suggested to be a causative agent for non-A-non-E hepatitis. However, several contradictory observations suggest that its ability to cause hepatitis is questionable. Taken together most data suggest that GBV-C/HGV is not a major cause of liver disease despite recent data indicating that it may infect and replicate in hepatocytes.

GB virus C/hepatitis G virus infection in chronic hepatitis C patients with and without interferon-alpha therapy

GB virus C/hepatitis G virus (GBV-C/HGV) RNA, detected by polymerase chain reaction, and antibodies to the GBV-C/HGV envelope protein (anti-E2), detected by an enzyme-linked immunosorbent assay, were used to evaluate both the impact of GBV-C/HGV on the coexistent hepatitis C virus (HCV) infection and the course of GBV-C/HGV infection in chronic hepatitis C patients with and without interferon-alpha (IFN-alpha) treatment. Of the 162 chronic hepatitis C patients treated with INF-alpha, 17.9% were GBV-C/HGV RNA-positive and 18.5% anti-E2-positive (total exposure, 35.2%). Neither present nor past GBV-C/HGV infection had impact on the clinical features, HCV virological characteristics and response to IFN-alpha treatment in chronic hepatitis C patients. Among patients with ongoing HCV/GBV-C/HGV coinfection, 20.7% (6/29) in IFN-alpha-treated patients lost GBV-C/HGV RNA concomitant with anti-E2 seropositivity, which was significantly higher than 4.8% (2/42) in patients without INF-alpha treatment (P<0.05). Based on multivariate analyses, the significant factors associated with clearance of GBV-C/HGV viremia combined with anti-E2 seropositivity were baseline anti-E2 seropositivity and IFN-alpha treatment. In summary, GBV-C/HGV did not alter the course of coexistent HCV. IFN-alpha treatment was effective in some patients against GBV-C/HGV and might facilitate anti-E2 seroconversion in chronic hepatitis C patients with GBV-C/HGV viremia.

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.

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.

GB virus type C/HGV markers in HCV RNA-positive French blood donors: correlation with HCV genotypes and risk factors

BACKGROUND

Exposure to GB virus type C/HGV (GBV-C/HGV) could be determined by detection either of RNA by RT-PCR or of antibodies of the envelope protein E2.

STUDY DESIGN AND METHODS

The aim of the study was to determine the proportion of the GBV-C/HGV markers of infection in a blood donor population infected with HCV and to identify GBV-C/HGV routes of transmission that are associated with HCV genotypes and risk factors.

RESULTS

Among 306 HCV RNA-positive blood donors, the proportion of GBV-C/HGV RNA-positive donors and anti-E2-positive donors was 19.3 percent (95% CI = 15.0-24.2%) and 42.1 percent (95% CI = 36.6-47.9%), respectively. Exposure to GBV-C/HGV (RNA or anti-E2) was significantly associated with the risk factor of IV drug use. There was a trend toward association with HCV subtypes 1a and 3a, probably because these HCV subtypes are the most frequent in IV drug users. No correlation was observed between ALT elevation and the presence of GBV-C/HGV RNA.

CONCLUSION

In persons with HCV infection, IV drug use seems to be a major route of GBV-C/HGV transmission. Precautions taken to avoid HCV infection will probably also decrease GBV-C/HGV transmission.

Insignificant role of hepatitis G virus infection in patients with liver enzyme elevations of unknown etiology

Hepatitis G virus (HGV) may cause acute and chronic infection in humans but its role in parenchymal liver injury and chronic hepatitis is obscure. In this study, the importance of HGV was investigated in patients with elevated aminotransferases alanine transaminase/aspartate transaminase (ALT/AST) levels of unknown etiology. We included 56 patients with elevated ALT/ AST levels of unknown etiology and 81 healthy controls in the study. HGV RNA was investigated by the reverse transcription polymerase chain reaction. The other possible causes of transaminase elevation were excluded with detailed biochemical and serologic tests. Liver biopsy was performed on 47 patients for histologic examination. HGV RNA was detected in only two patients (3.3%) and in one control (1.2%). There was no statistical difference between the groups. Liver biopsy revealed minimal inflammatory changes and steatosis in HGV RNA-positive patients. These observations indicated that HGV prevalence is not different from that of the general population in patients with liver transaminases elevation of unknown etiology. The role of this novel virus in the pathogenesis of chronic liver injury of unknown etiology appears insignificant in our geographic area.

[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.

Prevalence of hepatitis G virus in healthy children in liver disease, and human immunodeficiency virus-1 infection: response to interferon

BACKGROUND

A new virus of the Flaviviridae family, the hepatitis G virus (HGV/HGBV-C), has been identified recently. The purpose of this study was to determine the prevalence of HGV infection in healthy children, in patients with liver disease, and in human immunodeficiency virus (HIV)-1-infected patients. The role of HGV in the clinical course of chronic HCV, the response to interferon-alpha2b, and the possible implications of intravenous gamma-globulin in the transmission of the virus were also evaluated.

METHODS

Fifty healthy children, 66 patients with a variety of liver diseases, 19 patients with acquired immune deficiency syndrome (AIDS), and various batches of commercial intravenous immunoglobulins were investigated. Viral HGV RNA (5'NCR-NS5) and anti-HGV envelope protein E2 were assayed.

RESULTS

The prevalence of HGV infection was 6% in the healthy children and 42% in the liver disease group. Viremia and anti-E2 were found in 11% and 79% of patients with AIDS. Four (27%) of 15 patients with chronic HCV, receiving treatment with interferon, were coinfected by HGV and became HGV-RNA negative during therapy. One year after the end of interferon therapy, three of them were again HGV RNA positive.

CONCLUSIONS

The prevalence of HGV infection is high in healthy children higher in children affected with liver disease, but its potential pathologic implication is questionable, and further studies are warranted. Hepatitis G virus is sensitive to interferon therapy, although the infection often recurs after discontinuation of treatment.

Hepatitis C virus infection in special groups

Hepatitis C virus (HCV) infection is associated with a wide spectrum of clinical manifestations which may influence the choice of diagnostic assays, especially in haemodialysis patients, the clinical course of infection with possible multiple and sequential episodes of hepatitis in multiple transfused patients, and the severity of liver disease, especially in patients with HBV-HCV co-infection. The consequences of HCV infection in patients with organ graft are not completely understood due to the complexity of the clinical situations and the unavailability of long-term follow-up. Furthermore, current antiviral therapy is not very effective in these populations. Thus, it is especially important to protect patients at risk for HCV infection, using universal precautionary procedures.

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.

Hepatitis G virus: relevance to oral health care

OBJECTIVE

To review the current literature on the hepatitis G virus (HGV) infection, with particular attention to the aspects of interest for the dental staff.

MATERIAL AND METHODS

The authors searched for original research and review articles on specific aspects of the HGV infection including virology, epidemiology, transmission, natural history, and dental zaspects of HGV infection. The relevant articles were evaluated and reviewed.

RESULTS

HGV is a parenterally transmitted RNA virus that may cause acute, chronic, and fulminant liver disease; however, the real pathogenic potential of this virus and its possible effect on other hepatitic infections is still to be clarified. Preliminary studies have failed to demonstrate strong relationships between HGV infection and any oral disease. At present, data on the prevalence of HGV infection among health care workers are scarce. Nevertheless, in view of the potential transmission rates of HGV and the lack of effective immunization, HGV should be regarded as a potential occupational hazard for medical and dental staff.

CONCLUSION

Many virological, medical, and oral aspects of HGV infection need to be further investigated; nevertheless, until related data are available, HGV should be considered to be an infection that may be transmitted during dental care.

GBV-C/hepatitis G virus (HGV) RNA load in immunodeficient individuals and in immunocompetent individuals

The aim of this study was to establish the mean plasma GBV-C/hepatitis G virus (HGV) RNA load in groups of GBV-C/HGV-infected individuals with varied immune status and to determine the most frequent patterns of evolution of the plasma GBV-C/HGV RNA load over time during the natural history of infection. The mean plasma GBV-C/HGV RNA load observed was, from the lowest to the highest: 5.21 log in immunodepressed multiply-transfused patients, 6.45 log in HIV-positive individuals, 6.66 log in immunocompetent multiply-transfused patients, and 6.71 log in blood donors. The difference was significant between the four groups (P < 0.0001). The most frequent pattern of evolution of the plasma GBV-C/HGV RNA load was as follows: after the primary GBV-C/HGV infection, the viral load was elevated from the onset; then, a high, persistent and relatively steady viral RNA level was the rule; and when it occurred, the loss of viremia was not preceded by a decrease before recovery from GBV-C/HGV infection.

GB virus-C/hepatitis G virus infection in Taiwan: a virus that fails to cause a disease?

Recently, an RNA virus designated GB virus-C or hepatitis G virus (GBV-C/HGV) was identified; however, its clinical significance remains uncertain. This discovery prompted us to investigate the virological, epidemiological and clinical implications of GBV-C/HGV infection in Taiwan where chronic liver diseases and liver cancer are endemic. Our results showed that genetic heterogeneity of GBV-C/HGV isolates exists, and primers from the highly conserved 5' untranslated region of viral genome can efficiently detect GBV-C/HGV RNA. Epidemiological surveys showed that GBV-C/HGV infection is common in high-risk groups in Taiwan, and its coinfection does not aggravate the course of chronic hepatitis B or C. A prospective study of transfusion-transmitted GBV-C/HGV infection also showed GBV-C/HGV does not cause classic hepatitis in most patients. In addition, GBV-C/HGV plays a minimal role in causing fulminant hepatitis. Like hepatitis C virus, sexual transmission of GBV-C/HGV exists. The risk increases with prolonged duration of exposure. In addition, high-titered maternal viremia and mode of delivery are associated with the mother-to-infant transmission of GBV-C/HGV. Interestingly, we found that GBV-C/HGV exerts no suppression on levels of chronic hepatitis B or hepatitis C viremia, and GBV-C/HGV responds to interferon; however, ribavirin plus interferon does not induce a higher sustained response. As to the replication sites of GBV-C/HGV, our preliminary results showed liver and peripheral blood mononuclear cells are not the major sites for GBV-C/HGV replication, and thus GBV-C/HGV is not a primary hepatotropic virus. In conclusion, transfusion and exchange of body fluids indeed can transmit GBV-C/HGV; however, current lines of evidence suggest that GBV-C/HGV fails to cause a disease.

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.

Possible association between serum GB virus C RNA level and disease activity in fulminant hepatitis type G

BACKGROUND/AIMS

Whether GB virus C causes serious liver diseases remains controversial. The aim of the present study was to determine whether there is an etiological relationship between GB virus C and fulminant hepatitis.

METHODS

The level of GB virus C RNA in the sera of three patients with fulminant hepatitis was quantitatively determined using the newly developed real-time detection polymerase chain reaction method, which is based on Taq Man chemistry. The NS 3 region of the viral genome isolated from the sera was sequenced at several time points to confirm whether the same virus was responsible for fulminant hepatitis during the patients' clinical courses.

RESULTS

The sensitivity of the PCR was comparable to that of nested PCR and a linear relationship between RNA copy number and threshold cycle was observed for 10(1) and 10(6) RNA copies/ml (r = 0.99). The serum level of GB virus C RNA closely paralleled that of ALT in all patients. Sequence analysis of the NS3 region isolated from the patients' sera revealed that the same GB virus C strain infected the patients during their entire clinical courses, despite plasma exchange therapy.

CONCLUSIONS

These observations suggest that GB virus C may be etiologically associated with fulminant hepatic failure, and is not merely an inactive bystander introduced by therapeutic plasma exchange.

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.

Branched DNA signal amplification for direct quantitation of nucleic acid sequences in clinical specimens

In this chapter I have reviewed the development of bDNA as a method for quantitation of nucleic acid targets and the application of this technology to the study of infectious diseases and cell biology. The ability to quantify viral nucleic acids in clinical specimens has led to a better understanding of the pathogenesis of chronic viral infections such as HIV-1, HCV, and HBV. The information provided by these methods can also be important in the management of patients with these infections. The prognostic value of a single baseline HIV-1 RNA level rivals that surgical staging procedures for cancer, which are among the most powerfully predictive tests in medicine (Mellors et al., 1996). These methods have been used to assess rapidly the effects of antiviral therapy, which has both expedited the development of antiviral drugs and improved the management of patients with HIV-1 and HCV infections. bDNA has several characteristics that distinguish it from the quantitative target amplification systems, including better tolerance of target sequence variability, more direct measurement of target, simpler sample preparation, and less sample-to-sample variation. However, the first- and second-generation bDNA assays lacked sensitivity compared with the target amplifications systems. The changes incorporated into the third-generation assays have effectively increased the signal-to-noise ratio to such a high level that the analytical sensitivity of system 8 bDNA approaches that of PCR. In theory, bDNA can be made even more sensitive by increasing both the sample volume and the signal-to-noise ratio. Nonspecific hybridization can be further reduced by finding more effective blockers for the solid phase or by redesigning the amplifier molecule or the solid phase itself. The increased sensitivity may create new applications for the technology in filter and in situ hybridization assays.

Prevalence of GB virus-C/hepatitis G virus infection in patients with cryptogenic chronic liver disease and in patients with primary biliary cirrhosis or Wilson's disease

OBJECTIVE

To assess the role of hepatitis G virus (HGV) in cryptogenic chronic liver disease (CLD), we investigated the prevalence of HGV RNA among patients with cryptogenic CLD, patients with nonviral CLD (primary biliary cirrhosis [PBC] and Wilson's disease [WD]) and subjects without clinically evident liver disease (controls).

METHODS

Ninety patients with cryptogenic CLD (43 with chronic hepatitis, 20 with cirrhosis, and 27 with hepatocellular carcinoma [HCC]), 143 patients with PBC, 22 patients with WD, and 134 controls were recruited. HGV RNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) and antibodies against HGV E2 protein (anti-E2) by an immunoassay test.

RESULTS

HGV RNA was detected in 7.8% of patients with cryptogenic CLD (chronic hepatitis, 9.3%; cirrhosis, 5.0%; HCC, 7.4%), in 2.4% of patients with PBC or WD, and in 2.2% of controls. As a consequence, a positive association of HGV infection with cryptogenic CLD was found (odds ratio, 3.1; 95% confidence interval [CI], 1.0-9.7; p = 0.05). No difference was observed between HGV RNA-positive and -negative patients by age, sex, histology, or liver function tests. Anti-E2 prevalence did not differ between patients with cryptogenic CLD (26.5%), patients with PBC (28.1%), and controls (22.1%). Transfusion history was associated with HGV RNA but not with anti-E2 seropositivity.

CONCLUSIONS

Although an association was found between cryptogenic CLD and HGV infection, the role of the virus seems far from important, the proportion of cryptogenic CLD attributable to it being only 5.2%.

Dynamics of GB virus C viremia early after orthotopic liver transplantation indicates extrahepatic tissues as the predominant site of GB virus C replication

The principal site of GB virus C (GBV-C) replication is unknown. To determine whether hepatic GBV-C replication is important for the maintenance of a measurable viremia level in GBV-C infection, the influence of hepatectomy followed by liver transplantation on GBV-C viremia was investigated. GBV-C RNA levels were determined by a quantitative TaqMan polymerase chain reaction (PCR) in 12 patients with pretransplantation GBV-C infection before and daily after orthotopic liver transplantation (OLT) for 25 to 28 days. Compared with the pretransplantation values (mean, 12.4 +/- 3.9 x 10(7) copies/mL), mean GBV-C RNA levels declined significantly by 1 log by day 1 after OLT (mean, 3.5 +/- 1.6 x 10(7) copies/mL), but subsequently remained relatively stable on this high level for the entire observation period, indicating ongoing high-level virus replication (mean GBV-C RNA levels on days 7 and 28 were: 1.7 +/- 0. 5 x 10(7) and 2.8 +/- 0.7 x 10(7) copies/mL; P = ns). Thus, at the end of the follow-up, mean GBV-C RNA levels were not significantly different from that of the 1st and 7th postoperative day and remained significantly lower compared with the pretransplantation values. However, in 2 of the 12 patients, different kinetics were observed. Both already had low-level viremia pre-OLT (0.02 and 0.002 x 10(7) copies/mL) and became persistently GBV-C RNA-negative 2 days after OLT. In 5 patients, liver tissues were collected 6 to 9 days after OLT and investigated for GBV-C RNA. All but 1 were GBV-C RNA-negative in the liver, although 2 of them had rather high serum GBV-C RNA levels at this time. The kinetics of GBV-C viremia observed in our study were neither influenced by the immunosuppressive therapy nor by the number of blood and blood product transfusions given after OLT. In addition, they were quite different from those observed in patients with chronic hepatitis C in whom early reinfection of the graft could be demonstrated by a steady increase in HCV RNA levels starting 3 days after OLT and exceeding preoperative levels by day 8. From our data, one can conclude that the liver is certainly not the major site of GBV-C replication in most patients. However, one cannot exclude that host or viral factors exist that predispose GBV-C replication predominantly in the liver.

High prevalence of GB virus C/hepatitis G virus RNA in patients infected with human immunodeficiency virus

Prevalence of GBV-C/HGV was determined in a cohort of HIV-infected patients, via a reverse transcription-polymerase chain reaction detection of RNA in serum, amplifying the NS5 region of GBV-C/HGV genome. GBV-C/HGV RNA was detected in 143 (37.7%) of 379 patients, with similar results in the different HIV risk groups: 25/56 (44.6%) in intravenous drug users, 66/161 (41%) in homo- and bisexual men, 35/108 (32.4%) in heterosexual patients, 6/20 (30%) in transfusion recipients (P=0.41). There was no difference according to the presence or absence of hepatitis C virus infection. In univariate analysis, GBV-C/HGV genome prevalence was lower in patients over 50 years old (18.2%), compared to other age groups (20-29 years: 34.2%; 30-39 years: 44.3%; 40-49 years: 36.7%, P=0.03), as well as in patients with normal CD4 cell count (29.2% vs. 45.4% between 200-500/mm3, and 35.3% below 200 CD4/mm3, P=0.012) and individuals with a chronic hepatitis B. However, in the multivariate analysis, the only prognostic factor of GBV-C/HGV RNA positivity was the presence of a chronic hepatitis B, compared to the absence of any HBV marker, or a previous exposition to HBV (presence of anti-HBc and/or anti-HBs, absence of HBsAg), or the presence of anti-HBs alone.

High prevalence of GB-C/hepatitis G virus in a Brazilian population with helminth infection

A study of GB-C virus/Hepatitis G virus (GBV-C/ HGV) infection was carried out in a rural population of Northeastern Brazil, in which the prevalence of schistosomiasis is 80-90%. Despite the absence of parenteral risk exposure, the prevalence of GBV-C/HGV markers of infection was found to be unusually increased: viremia, 16.4%; specific antibody, 18.3%. It is therefore suspected that helminth infection influenced the immune response to GBV-C/HGV infection by shifting the balance of cytokine responses from Th1 to Th2, resulting in a delayed viral clearance. Phylogenetic analysis of viral isolates did not provide evidence for high rates of sexual or mother-to-infant viral transmission. The study revealed that viral strains belonged to types 1 and 2 only (predominant in Africa and Europe, respectively), suggesting that GBV-C/HGV was introduced into the New World by white conquerors and black slaves since the 16th century.

Influence of GB virus-C/hepatitis G virus infection on the long-term course of chronic hepatitis B

AIMS/BACKGROUND

The clinical significance of GB virus-C/hepatitis G virus (GBV-C/HGV) infection in chronic hepatitis B is not well known and its role in the outcome of liver disease was investigated.

METHODS

HGV-RNA and antibody to HGV (anti-E2) were studied in 125 patients with chronic hepatitis B (41 with multiple hepatitis virus exposure), 82 asymptomatic HBsAg carriers and 103 healthy adults.

RESULTS

In chronic hepatitis B, HGV-RNA was more frequent in patients with HDV infection and/or anti-HCV positivity than in those without (29% vs 6%, p<0.0001), mainly in drug addicts (38%). At diagnosis the overall prevalence of any marker (HGV-RNA plus anti-E2) was similar in chronic hepatitis due to HBV alone (17%), in HBsAg carriers (16%) and in healthy adults (17%) and increased to 58% in those exposed to HDV and/or HCV. During 1-11 years of follow-up, HGV infection persisted in 70% of patients with chronic hepatitis B. About 400% of HGV persistently coinfected patients underwent sustained biochemical remission, whereas continuing disease activity was observed in 80% of patients who cleared HGV-RNA.

CONCLUSIONS

In chronic HBV infection the rate of exposure to HGV is similar to that in healthy adults, except for high risk patients. Long lasting HGV coinfection or anti-E2 seroconversion did not modify the course of chronic hepatitis B.

Hepatitis G Virus RNA and Hepatitis G Virus-E2 Antibodies in Dutch Hemophilia Patients in Relation to Transfusion History

The prevalence of hepatitis G virus (HGV)-RNA and HGV-E2 antibodies was studied in a cohort of Dutch hemophilia patients in relation to clotting products used, age, and coinfection with hepatitis C. Between 1991 and 1995, blood samples were taken from 294 patients with hemophilia A, B, or von Willebrand disease. From each patient one fresh frozen sample was tested for HGV cDNA polymerase chain reaction (PCR) and HCV cDNA PCR. Alanine aminotransferase (ALT) tests were performed on plasma samples of all patients. The presence of HGV-E2 antibodies was tested on plasma samples from a subset of 169 patients representing all age groups. Based on the origin and viral safety of the products used, three subgroups of patients were distinguished. Group A: patients who used viral noninactivated factors derived from small and large donor pools; group B: patients who used factors prepared with inadequate viral inactivation techniques derived from small and large donor pools; and group C: patients treated only with optimally viral inactivated large pool clotting factor or recombinant clotting factor concentrate. The prevalence of HGV-RNA was 18%. In group A patients the prevalence was 71%, in group B 50%, and in group C 6%. When related to age, the highest prevalence of HGV-RNA (35%) was seen in patients born between 1980 and 1989. The prevalence of HGV-E2 antibodies increased with age. Of HGV-RNA–negative patients born before 1950, 96% tested positive. HGV viremia did not affect ALT levels, neither in HCV-RNA positive nor in HCV-RNA negative patients. HGV infection is frequently seen in patients with hemophilia. In older age groups a lower rate of HGV-RNA positivity is seen coinciding with a higher rate of antienvelope antibodies.

© 1998 by The American Society of Hematology.

Hepatitis G Virus RNA and Hepatitis G Virus-E2 Antibodies in Dutch Hemophilia Patients in Relation to Transfusion History

The prevalence of hepatitis G virus (HGV)-RNA and HGV-E2 antibodies was studied in a cohort of Dutch hemophilia patients in relation to clotting products used, age, and coinfection with hepatitis C. Between 1991 and 1995, blood samples were taken from 294 patients with hemophilia A, B, or von Willebrand disease. From each patient one fresh frozen sample was tested for HGV cDNA polymerase chain reaction (PCR) and HCV cDNA PCR. Alanine aminotransferase (ALT) tests were performed on plasma samples of all patients. The presence of HGV-E2 antibodies was tested on plasma samples from a subset of 169 patients representing all age groups. Based on the origin and viral safety of the products used, three subgroups of patients were distinguished. Group A: patients who used viral noninactivated factors derived from small and large donor pools; group B: patients who used factors prepared with inadequate viral inactivation techniques derived from small and large donor pools; and group C: patients treated only with optimally viral inactivated large pool clotting factor or recombinant clotting factor concentrate. The prevalence of HGV-RNA was 18%. In group A patients the prevalence was 71%, in group B 50%, and in group C 6%. When related to age, the highest prevalence of HGV-RNA (35%) was seen in patients born between 1980 and 1989. The prevalence of HGV-E2 antibodies increased with age. Of HGV-RNA–negative patients born before 1950, 96% tested positive. HGV viremia did not affect ALT levels, neither in HCV-RNA positive nor in HCV-RNA negative patients. HGV infection is frequently seen in patients with hemophilia. In older age groups a lower rate of HGV-RNA positivity is seen coinciding with a higher rate of antienvelope antibodies.

© 1998 by The American Society of Hematology.

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.

Evolution of hepatitis G virus infection and antibody response to envelope protein in patients with transfusion-associated non-A, non-B hepatitis

The clinical significance and course of acute hepatitis G virus (HGV) infection were studied by measuring HGV RNA and antibody to HGV envelope protein E2 (HGV-E2 antibody). A total of 59 patients with transfusion-associated non-A, non-B hepatitis, who were followed-up for more than 1 year, were selected retrospectively. HGV RNA was measured by reverse transcriptase (RT) and nested polymerase chain reaction (PCR) was performed, using primer sets, in the 5'-non-coding region of the HGV genome. HGV-E2 antibody was measured by enzyme-linked immunosorbent assay (ELISA) using recombinant E2 protein. Of the 59 patients, 51 (86%) were infected with hepatitis C virus (HCV) and 12 (20%) were infected with HGV; 11 of the 12 with HGV infection were also infected with HCV. HGV viraemia was cleared during the follow-up period in seven of the 12 patients with HGV infection. All these seven patients seroconverted for HGV-E2 antibody just before or just after the clearance of HGV viraemia. In contrast, all five patients without clearance of HGV viraemia were negative for HGV-E2 antibody (P = 0.0013). Of seven patients with continuous HGV viraemia at 1 year from the onset of acute hepatitis, four with HCV RNA showed chronic elevation of alanine aminotransferase (ALT) but three without HCV RNA did not. The severity of acute hepatitis was similar between patients with both HGV and HCV infections and in those with HCV infection alone. The majority of patients with HGV infection cleared the virus during long-term follow-up. Appearance of HGV-E2 antibody was associated with the clearance of HGV viraemia. An abnormal ALT level was noted to depend on HCV infection but not on HGV infection in both the acute and chronic phases of transfusion-associated hepatitis.

Epidemiology of hepatitis C and G in sporadic and familial porphyria cutanea tarda

From 1995 to 1997, we prospectively evaluated the prevalence of hepatitis C virus (HCV) RNA in 124 patients with porphyria cutanea tarda (PCT) from Northern France (83 sporadic and 41 familial PCT). Serum samples were analyzed for ferritin, transaminases, HCV antibodies, and HCV RNA. In addition, genotyping of HCV and searches for HCV infection risk factors (blood transfusion, iv drug abuse, and surgical intervention) were performed. Twenty-six of 124 patients (21%; 95% CI: 13.9-28) were positive for serum HCV antibodies. All of them were also positive for HCV RNA. The prevalence of HCV infection was higher in the sporadic PCT group (26.5%, 22 out of 83) than in the familial PCT group (9.7%, 4 out of 41). Risk factors for hepatitis C infection were found to be significantly increased in the HCV-positive group when compared with the HCV-negative PCT group. In all HCV-positive patients with a risk factor, the suspected date of exposure to the virus always preceded the clinical onset of PCT. The HCV genotype pattern in PCT patients was similar to that observed in nonporphyric HCV patients in western European countries. Serum ferritin level was increased in both HCV-positive and HCV-negative porphyric patients. Transaminase levels were significantly higher in HCV-infected PCT patients. Sixty-seven out of 124 patients were retrospectively studied for hepatitis G virus (HGV) infection. Six of these 67 patients (8.9%; 95% CI: 2.1-15.8) were positive for HGV RNA. None of the six HGV-infected patients were positive for HCV RNA. The HGV-infected patients did not differ statistically from those without HGV infection with regard to age, ferritin, transaminase levels, and PCT treatment. These results support the view that sporadic cases of HGV infection may occur frequently. This study of a large cohort of HCV and PCT patients further documents an increasing gradient in HCV prevalence from northern to southern Europe, and shows that HCV infection acts as a triggering factor of PCT. Finally, the HGV prevalence found in the PCT patients was comparable with that found in French blood donors, suggesting that HGV is not a PCT triggering factor.

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.

Acute hepatitis induced by alpha-interferon, associated with viral clearance, in chronic hepatitis C

We describe the cases of two patients with chronic hepatitis C who developed acute hepatitis with marked amino-transferase elevations and jaundice 3 and 5 months after initiation of interferon treatment. Hepatitis resolved rapidly after cessation of interferon. No autoantibodies were detected. Hepatitis was followed by viral clearance, demonstrated by clearance of hepatitis C viraemia. We propose that hepatitis may be due to an immune lysis of hepatocytes and suggest that this immune response may contribute to viral clearance.