Replicative efficiency and pathogenicity of hepatitis B virus e-minus precore variant

Abstract To study the replicative efficiency and pathogenicity of hepatitis B virus precore variant (A1896), anti-hepatitis B virus e antigen (HBe) titre was studied in naturally occurring wild-type virus infection, A1896 variant infection and dual infection. Higher titre of anti-HBe was found in patients with no virus replication and in patients coinfected with the wild-type virus and A1896 variant, which suggest that anti-HBe may either act as an inhibitor of virus replication or as selective pressure for the A1896 variant. Three site-directed mutants were constructed in the duck hepatitis B virus (DHBV) precore region. A frame shift in the encapsidation signal region abolished replication of DHBV; mutation in the initiation codon of the precore and mutation to generate a termination codon at the distal region of the precore resulted in decreased replication in the duck model. More significant pathological changes were found in the liver tissues of ducks infected with the mutant which mimicked the HBV A1896 variant.     

庚型肝炎病毒感染对急性肝炎致病性的探讨

目的 探讨急性肝炎患者肝组织中庚型肝炎病毒（ＨＧＶ）的感染状况及其致病性。方法 采用免疫组织化学方法对３７例血清学肝炎病毒标记甲￣戊型均阴性的急性肝炎患者肝穿肝组织中的ＨＧＶ ＮＳ５抗原等进行检测,并对ＨＧＶ感染的致病性进行研究。结果 ＨＧＶ ＮＳ５抗原的检出率为３７．８％（１４／３７）,其中ＨＧＶ ＮＳ５单项阳性４例（急性庚型肝炎组）。结果 ＨＧＶ ＮＳ５抗原的检出率为３７．８％（１４／３７）,     

High prevalence, low pathogenicity in hepatitis G virus in kidney transplant recipients

BACKGROUND: Prevalence and pathogenicity of hepatitis G virus infection in long-term renal transplant recipients, are not fully known. AIM: To evaluate long-term impact of HGV infection on liver disease of renal transplanted patients. PATIENTS AND METHODS: A total of 155 hepatitis B surface antigen negative kidney transplant recipients, followed for a mean of 11 years after renal transplantation, were studied. Of these 48 (31%) patients had persistently elevated serum aminotransferase values. Frozen serum samples were tested for HGV-RNA and HCV-RNA by nested reverse transcribed polymerase chain reaction, and for anti-hepatitis G virus and anti-hepatitis C virus by enzyme-linked immunosorbent assay Hepatitis C virus-RNA was typed by a line probe assay and quantified by a branched DNA signal amplification assay RESULTS: Hepatitis G virus-RNA was detected in 37 (24%) patients and anti-hepatitis G virus in another 26 (17%). Seventy (45%) patients had serum anti-hepatitis C virus and 63 of these (90%) had serum hepatitis C virus-RNA. Hepatitis G virus-RNA positive and negative patients were similar in terms of age, sex, duration of dialysis, rate of transfusion, chronic liver disease, rate of hepatitis C virus infection and immunosuppressive therapy. Fifteen (41%) hepatitis G virus-RNA seropositive patients were hepatitis C virus co-infected. Hepatitis C virus-RNA levels were significantly lower in the 15 hepatitis C virus/hepatitis G virus co-infected patients than in the 48 patients with hepatitis C virus infection only (2.2 vs 10.8 MEq/ml, p = 0.02). Only 3 hepatitis G virus carriers had persistently elevated alanine aminotransferase compared to 29 hepatitis C virus carriers (14% vs 60%, p < 0.001), 10 patients co-infected with both hepatitis G virus and hepatitis C virus, and in 6 patients with neither infection (67% vs 8%, p < 0.001). CONCLUSIONS: Hepatitis G virus infection is common among kidney transplant patients, it carries a low risk of chronic liver disease even in long-term follow-up. Low levels of hepatitis C virus-RNA found in hepatitis G virus carriers suggest an interaction between these two viruses in immunosuppressed patients.     

Expression and characterization of the hepatitis G virus helicase

The hepatitis G virus (HGV) is a new member of the Flaviviridae family and has a genomic organization similar to that of hepatitis C virus (HCV). Protein sequence motifs are present suggesting that HGV encodes a serine proteinase, an RNA-dependent RNA polymerase and a helicase. We have cloned and expressed the putative helicase of HGV and have shown that it contains a poly (U)-stimulated NTPase activity and is able to function as a DNA helicase. Preliminary characterization of the HGV helicase activity reveals similarities with other members of the Flaviviridae, but especially with HCV, raising the possibility that HGV could be used as a surrogate virus for the development of therapies against HCV.     

Clinical significance of hepatitis G virus infection in patients on long-term haemodialysis

Infection with the newly discovered hepatitis G virus (HGV) was analysed in 163 patients on long-term haemodialysis to clarify its prevalence and clinical significance. Hepatitis G virus RNA in serum was measured by polymerase chain reaction with primers corresponding to the putative non-structural 5’ region. Of the 163 patients, three (1.8%) were positive for hepatitis B surface antigen, 40 (24.5%) were positive for hepatitis C virus (HCV)-RNA and 16 (9.8%) were positive for HGV-RNA. Five of the 16 patients with HGV-RNA were also positive for HCV-RNA. Patients with HCV and HGV coinfection had undergone a longer duration of haemodialysis (P=0.001) and had higher units of transfusion (P=0.031) compared with those without hepatitis virus infection. Transfusion history was significantly higher (P=0.039) in patients with only HGV infection than in those without hepatitis virus infection. Hepatitis C virus RNA concentration was higher (P=0.032) in patients with HCV and HGV coinfection than in those with HCV infection only, but alanine aminotransferase (ALT) levels were similar between these two groups. In conclusion, about 10% of patients on haemodialysis were infected with HGV and the infection was closely associated with transfusion history.     

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.     

重庆地区HGV感染的分子流行病学

目的 探讨重庆地区HGV感染和基因型特征,了解致病性和传播途径。方法 用RT-PCR和ELlSA方法检测685例献血员和76例血液透析患者HGV感染状况,比较肝功能和重叠感染情况并进行部分病例随访;进行HGV 5-NCR测序。结果 本地存在HGV感染．血液透析患者HGV RNA阳性率(36％)明显高于献血员抗-HGV阳性率(3％),约半数透析患者HGV合并HCV和HBV感染;基因分型表明属于第3组3b亚型。结论 HGV主要经血传播,感染HGV透析患者未发现有明显致病性;基因分型有助于深入探讨病毒致病性和变异。     

Effects of HAART on hepatitis C, hepatitis G, and TT virus in multiply coinfected HIV-positive patients with haemophilia

In multiply coinfected human immunodeficiency virus (HIV)-positive patients, we investigated the effects of high-activity antiretroviral therapy (HAART) using HIV protease inhibitors on three other viruses: hepatitis C virus (HCV), hepatitis G virus (HGV), and TT virus (TTV). Viral concentrations were measured serially by polymerase chain reaction methods in five patients with quadruple infection (HIV, HCV, HGV, and TTV) and in two patients with triple infection (HIV, HCV, and HGV) before and during HAART. In addition, CD4+ cell counts and serum alanine aminotransferase (ALT) levels were measured serially. Generally we observed no difference in serum HCV RNA, HGV RNA, or TTV DNA concentrations between samples obtained before and after initiation of HAART, whereas HIV RNA concentration decreased and CD4 counts increased in most patients. However, two patients had markedly decreased concentrations of HCV RNA and HGV RNA, respectively, more than 12 months after beginning HAART. Normalization of serum ALT levels was observed in a patient with decline of HCV RNA concentrations. No interactions were observed among these four viruses. HAART had no apparent direct effects on HCV, HGV, or TTV. Further studies will be required to elucidate whether the restoration of immune status through suppression of HIV replication by HAART may affect HCV or HGV RNA concentrations.     

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

Abstract: 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 40% 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.     

Prevalence and clinical significance of GB virus type C/hepatitis G virus coinfection in patients with chronic hepatitis C undergoing antiviral therapy

Summary. Coinfection with GBV‐C/HGV in patients with chronic hepatitis C (CHC) may influence clinical course and response rates of antiviral therapy. Aim of the study was to investigate the prevalence of GBV‐C/HGV/HCV coinfection and its influence on outcome of interferon/ribavirin combination therapy. Three hundred and four patients with CHC [m/f = 211/93, age: 42 (18–65)] were investigated. HGV RNA detection was performed by polymerase chain reaction prior to and 6 months after the end of antiviral therapy. HGV/HCV coinfection could be identified in 37/304 (12.2%) patients with intravenous drug abuse as the most common source of infection (N = 21, (56.8%)). The predominant HCV genotype in coinfected individuals was HCV‐3a (HCV‐3a: 51.4%, HCV‐1: 37.8%, HCV‐4: 10.8%). HGV coinfection was more prevalent in patients infected with HCV‐3 compared to HCV‐1 or HCV‐4 [19/45 (42.2%) vs 14/185 (7.6%) vs 4/52 (7.7%), P < 0.01]. Patients with HGV/HCV coinfection were younger [35 (18–56) vs 43 (19–65), years; P < 0.01], and advanced fibrosis (F3‐F4) was less frequent (22.2%vs 42.9%, P < 0.05). A sustained virological response was achieved more frequently in HGV/HCV coinfected patients [26/37 (70.3%)] than in monoinfected patients [120/267 (44.9%), P < 0.01]. HGV RNA was undetectable in 65.7% of the coinfected patients at the end of follow‐up. Intravenous drug abuse seems to be a major risk factor for HGV coinfection in patients with chronic hepatitis C. Coinfection with HGV does not worsen the clinical course of chronic hepatitis C or diminish response of HCV to antiviral therapy. Interferon/ribavirin combination therapy also clears HGV infection in a high proportion of cases.     

Hepatitis G virus RNA and its relation to hepatitis C infection in adult haemophilic patients

The prevalence of hepatitis C virus (HCV) infection and hepatitis G virus (HGV) RNA were studied in 50 adult haemophilic patients who had received commercial clotting factors prior to 1980. HGV RNA was detectable in 6/50 patients (12%); 49/50 (98%) had antibody to HCV and 40/49 (82%) of these were viraemic with detectable HCV RNA; 5/6 patients with detectable HGV RNA had co-existing HCV infection and viraemia. The HGV PCR products from all six patients were directly sequenced and all were shown to be similar to that of HGV but more diverse from that of GB virus C. One patient who had persistent abnormal liver function tests had detectable HGV RNA but no evidence of hepatitis B or C. The presence of HGV RNA in the absence of hepatitis B and C infection indicates that this virus is capable of independent transmission. Independent response to interferon was demonstrated in one patient with co-infection who lost HGV but not HCV after interferon therapy.     

Biochemical and histological features of hepatitis G virus infection

To assess the biochemical and histological characteristics of hepatitis G virus (HGV) infection, we examined four patients who were infected with HGV only (HGV group), and compared them with 16 patients infected with both HGV and hepatitis C virus (HCV; HGV + HCV group) and 18 patients infected with HCV only (HCV group). Biochemical examination showed a significantly low level of serum alanine aminotransferase (ALT) in the HGV group, and that the gamma-glutamyl transpeptidase (γ-GTP)/ALT ratio in the same group was significantly higher than in the other two groups. Although all three patient groups had a similar degree of liver fibrosis, both the degree of periportal inflammation and total histological activity index were significantly lower in the HGV group than in the other two groups. Fibrous enlargement of the portal tract without lymphoid infiltration and thin fibrous septa was characteristically observed in the HGV group. No significant difference was found between the HGV + HCV group and HCV group. Our results suggest that biochemical and histological changes in HGV infection are very mild and quite different from those of HCV infection.     

Prevalence of hepatitis G virus RNA in a monocentric population of French haemophiliacs

Hepatitis G virus (HGV) and hepatitis GB virus (GBV-C) have been reported as possible causes of non-A–E transfusional hepatitis. To assess the prevalence of hepatitis G virus infection in haemophiliacs we retrospectively investigated the presence of viral RNA in 92 patients with and without HCV infection. HGV/GBV-C RNA was reverse transcribed and amplified with primers from the 5' non-coding region of the genome. RNA was detected in 16/92 patients (17.4%). Restriction enzyme analysis revealed that the 16 patients belonged to the HGV-like genotype. Serology with E2-specific antibodies demonstrated that HGV viraemia underestimates previous infection by HGV. 33 patients were positive for HGV; all but two have cleared HGV RNA. 47/92 patients had a marker of prior infection by HGV.
No difference between HGV RNA positive and negative patients was observed concerning age, diagnosis, HIV and HCV status. Previous HBV infection correlated with the frequency of HGV infection. There was no difference in alanine aminotransferase levels between HGV positive and negative patients. All 18 patients exposed to only virally inactivated plasma-derived concentrates were negative for both HGV RNA and anti E2 antibodies.
Prior exposure to untreated concentrates correlated with HGV viraemia ( P =0.03), HGV seropositivity ( P =0.0002), and markers of HGV infection ( P <0.0001).
In haemophiliacs with a past exposure to non-inactivated concentrates, persistence of HCV RNA (53/74 patients) was more frequent than HGV RNA persistence (16/74 patients) although HGV viraemia is more frequent than HCV viraemia in blood donors. This may be related to a greater ability of individuals to clear HGV infection and suggests that hepatitis G virus infection in multi-transfused patients has a better outcome than infection with other blood-borne viruses.     

Interferon treatment of two patients with quadruple infection with hepatitis C virus (HCV), human immunodeficiency virus (HIV), hepatitis G virus (HGV), and TT virus (TTV)

Abstract: We administered interferon (IFN) to two patients who had quadruple infection with hepatitis C virus (HCV), human immunodeficiency virus (HIV), hepatitis G virus (HGV), and TT virus (TTV), a recently isolated novel DNA virus. Nine mega-units of natural alpha-IFN were administered daily during the first two weeks and thrice weekly during the following 22 weeks (total dose, 720 mega-units). In both cases, serum alanine aminotransferase (ALT) levels decreased during IFN administration but increased thereafter. The concentrations of HCV, HIV, HGV, and TTV declined with the administration of IFN. However, the concentrations of these 4 viruses increased after the cessation of IFN with the except of TTV in patient 2 which disappeared during treatment and did not subsequently reappear. IFN reduced the concentrations of 4 viruses, in an apparently independent manner.     

Two patients with acute hepatitis B with suspected sexual transmission of hepatitis G virus

Two patients with acute hepatitis B with suggested sexual transmission of hepatitis G virus (HGV) are reported. A total of 18 patients with community acquired acute hepatitis B were analyzed in this study. Two of the 18 patients (patients 1 and 2) were positive for serum HGV RNA at the initial consultation. Both patients had had sexual contact with prostitutes several weeks before the onset of acute hepatitis, and hepatitis B virus (HBV) was suggested to be infected through the sexual contacts. These patients showed no other history of exposure to possible transmission routes for blood-borne hepatitis viruses. Patient 1 was diagnosed as with acute HGV infection because the antibody to HGV envelope-2 protein seroconverted to positive during the course of acute hepatitis. HGV RNA was negative in a serum sample collected from patient 2 before the onset of acute hepatitis, also suggesting acute HGV infection. These results indicate that in patients 1 and 2 HGV was infected along with HBV through sexual contact. The clinical manifestations of acute hepatitis in the two patients with HGV co-infection did not differ from those in the 16 patients with HBV infection alone. (Received Aug. 6, 1997; accepted Oct. 30, 1997)