Infection with GB virus C in leprous patients in Japan

Viral co-infections in leprosy: a scoping review

CONTEXT

The most reported viral co-infections in leprosy are human immunodeficiency virus (HIV), human T-cell lymphotropic virus (HTLV), hepatitis B virus (HBV), hepatitis C virus (HCV), and SARS-CoV-2. In co-infections, the burden of an agent can be increased or decreased by the presence of others. To address this issue, we need to fully understand their prevalence, risk factors, immunology, clinical manifestations, and treatment. The purpose of this scoping review is to describe the clinical and epidemiological characteristics of the most reported viral co-infections in leprosy to inform clinicians and guide future research.

METHODS

The authors conducted a literature search of five databases for articles on each of the aforementioned co-infections published prior to October 2022. Two independent reviewers conducted the selection process and identified 53 papers meeting the study inclusion criteria. The data extraction process and evidence synthesis were conducted by one reviewer and double-checked by a second one, consistent with best practice recommendations for scoping reviews.

RESULTS

For all assessed viruses, most studies reported prevalence rates in leprosy patients higher than the general population. Studies found that HTLV, HBV, and HCV chronic infections were highest in multibacillary leprosy, whereas HIV was mostly found in paucibacillary leprosy, and SARS-Cov-2 affected leprosy subtypes equally. Overall, co-infections were also associated with higher rates of leprosy reactions, except for COVID-19. Forty-six percent of the studies discussed issues related to treatment, which led to favorable outcomes for the most part.

CONCLUSIONS

This review summarizes the existing literature on viral co-infections in leprosy patients, generating valuable insights and recommending areas for future research.

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.

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.

High prevalence of GB virus C in Brazil and molecular evidence for intrafamilial transmission

The prevalence of GB virus C (GBV-C) in candidate Brazilian blood donors with normal and elevated alanine aminotransferase levels was found to be 5.2% (5 of 95) and 6.5% (5 of 76), respectively. Among Brazilian patients, GBV-C was found in 9.5% (13 of 137) of cases of hepatitis not caused by hepatitis A virus (HAV), HBV, HCV, HDV, or HEV (non-A-E hepatitis) and in 18.2% (8 of 44) of individuals infected with HCV. Molecular characterization of GBV-C by partial sequencing of the NS3 region showed clustering between members of a single family, implying intrafamilial transmission. In conclusion, these results together suggest that contagion mechanisms which facilitate intrafamilial transmission of GBV-C may partially explain the high prevalence of viremic carriers worldwide.

GB virus C prevalence in blood donors and high risk groups for parenterally transmitted agents from Gauteng, South Africa

The prevalence of GBV-C infection in voluntary blood donors and in groups at high risk for parenteral exposure to infectious agents was studied. The high risk groups included chronic renal failure patients on haemodialysis, renal transplant patients and haemophiliacs from Gauteng. The presence of GBV-C RNA in these populations was determined using reverse transcription polymerase chain reaction (RT-PCR) in the 5' non-coding region (NCR) of the virus. Of the blood donors, 11.1% (95% CI 7.6, 15.8) were positive, whereas 23.8% (95% CI 12.6, 40.2) of haemodialysis patients and 23.5% (95% CI 15.9, 33.3) of the haemophiliacs were infected with GBV-C. The highest proportion of infection was in the renal transplant patients, where 41.2% (95% CI 35.1, 47.7) were found to have circulating GBV-C RNA. Serological markers for hepatitis B (HBV) and hepatitis C viruses (HCV) were also measured as indicators of other hepatitis viruses with important parenteral transmission routes. Of the GBV-C positive blood donors, 3.6% were also HBsAg positive and none were positive for HCV. The GBV-C positive patients on haemodialysis were not positive for either HBsAg or antibodies to HCV, but had evidence of past infection with HBV since 40% were anti-HBc positive. The greatest proportion of HCV positives was in the haemophiliac group, 91.3%, none of these were HBsAg positive but 39.1% had anti-HBc. In the GBV-C positive renal transplant patients, 4% had HBsAg, 13.3% had anti-HBc and 2.1% had antibodies to HCV. This is the first report describing the prevalence of GBV-C in South African populations.

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.

Detection of hepatitis G virus RNA in persons with and without known risk factors for blood-borne viral infections in Sweden and Honduras

We analyzed 224 and 163 serum samples from individuals in Sweden and Honduras, respectively, for the presence of the hepatitis G virus (HGV or GB virus-C) RNA. HGV infection in both Sweden and Honduras was related to common risk factors for blood-borne infections, despite a surprisingly high frequency in groups without known risk factors.

Current status of hepatitis G virus (GBV-C) in transfusion: is it relevant?

A new flavivirus, provisionally designated hepatitis G virus or GBV-C has recently been described. The virus is parenterally transmitted by exposure to blood through transfusion, intravenous drug use and haemodialysis. Heat- or chemically-treated blood products are associated with reduced risk of infection. The virus may also be transmitted from mother to infant and by the sexual route. Although hepatitis G virus has been detected in patients with acute and chronic hepatitis, a causative role of the virus in such cases has not been established. The majority of long term carriers of the virus appear to have no liver, biochemical or histological abnormalities.

GB virus-C RNA in Japanese patients with hepatocellular carcinoma and cirrhosis

BACKGROUND/AIMS

The involvement of non-B, non-C virus in the incidence of hepatocellular carcinoma (HCC) is not yet known. We have therefore examined the occurrence of GBV-C RNA in such patients.

METHODS

One hundred and eleven patients diagnosed as having HCC and 67 patients with cirrhosis without HCC were examined for the prevalence of GBV-C RNA by nested reverse transcription polymerase chain reaction with primers located at the helicase region. Sera were obtained and kept at -20 degrees C until analysis.

RESULTS

GBV-C RNA was positive in 11/111 (9.9%) cases with HCC, in 10/74 (13.5%) anti-HCV positive cases, in 1/25 (4%) HBsAg positive cases, and in 0/8 (0%) anti-HCV and HBsAg negative cases. GBV-C RNA was also positive in 7/67 (10.4%) cases with cirrhosis, in only 1/18 (5.6%) anti-HCV and HBsAg negative cases, in 4/33 (12.1%) anti-HCV positive, and in 2/14 (14.3%) HBsAg positive cases. The clinical background of patients with anti-HCV positive HCC who were also positive for GBV-C RNA did not differ from the background of those negative for GBV-C RNA.

CONCLUSIONS

GBV-C is unlikely to be a major etiologic agent of non-B, non-C chronic liver diseases and HCC in Japan.

Infection with GB virus C/hepatitis G virus in Brazilian hemodialysis and hepatitis patients and asymptomatic individuals

Recently, sequences from a novel human flavivirus, termed GB virus C (GBV-C) or hepatitis G virus (HGV), have been identified in serum from patients with cryptogenic hepatitis and others. Sera from 116 patients with different clinical backgrounds were tested for the presence of GBV-C/HGV RNA by a reverse transcription-polymerase chain reaction with primers from the nonstructural (NS) 5 region. Ten (15%) patients on maintenance hemodialysis and 5 (19%) non A-C hepatitis patients were GBV-C/HGV RNA positive, along with one patient with chronic hepatitis B, one patient with chronic hepatitis C, and two asymptomatic individuals. Sequence comparison within 354 base pairs in the NS5 region showed homology rates varying from 87% to 97% among five Brazilian isolates, and from 86% to 93% between Brazilian strains and GBV-C/HGV isolates from other countries previously sequenced. Homology rates were higher at the amino acid level since most substitutions occurred at the third nucleotide position of codons without changing the codon meaning.

Infection with GB virus C and hepatitis C virus in hemodialysis patients and blood donors in Beijing

RNAs of GB virus C (GBV-C) and hepatitis C virus (HCV) were sought by reverse-transcription polymerase chain reaction with nested primers deduced from the 5' untranslated region: 79 patients on maintenance hemodialysis, 205 commercial blood donors, and 205 voluntary donors in Beijing were studied. GBV-C RNA was detected in 43 (54%) patients and 17 (8%) commercial donors, and HCV RNA in 43 (54%) patients and 13 (6%) commercial donors, respectively. By contrast, GBV-C RNA was detected only in 2 (1%) and HCV RNA in none among 205 volunteer blood donors serving as controls. Thus both patients and commercial blood donors were at higher risk for infection with GBV-C (P < 0.001) than controls. HCV RNA was detected more often in patients with GBV-C RNA than without (29/43 or 67%, vs. 14/36 or 39%, P < 0.05) as well as in commercial donors with GBV-C RNA than without (5/17 or 29% vs. 8/188 or 4%, P < 0.01). A phylogenetic tree constructed on a sequence of 100 base pairs in the helicase region indicated that GBV-C isolates from Beijing are more similar to Japanese isolates than to isolates from the United States and Africa. Sequences from certain hemodialysis patients and those from some commercial donors were similar, suggesting nosocomial infection and spread among restricted groups.

Hepatitis G virus infection in chronic hepatitis C: frequency, features and response to interferon therapy

BACKGROUND/AIMS

The pathogenic relevance of the hepatitis G virus (HGV) and its sensitivity to interferon are currently under investigation. This study aimed to investigate the prevalence of HGV infection in patients with chronic hepatitis C and to elucidate if HGV co-infection modifies the clinical course and the response to interferon therapy in this disease.

METHODS

HGV-RNA was investigated by reverse transcription-polymerase chain reaction in serum from 143 consecutive patients who received interferon alpha-2b (3 MU t.i.w.) for 24 weeks. Baseline features and response to therapy in HGV-infected and non-infected patients were compared. To assess the antiviral effect of interferon, serial quantitative measurement of HCV-RNA and HGV-RNA in serum was performed in patients co-infected with HCV and HGV.

RESULTS

Eight patients (5.6%) presented HGV-RNA sequences in serum. No significant differences were found between HGV-infected and non-infected patients in relation to age, sex, source of infection, liver function tests, liver histology and HCV genotype, nor in the biochemical response to interferon, which was sustained in 12% and 15%, transient in 37% and 30% and absent in 50% and 55% of HGV-infected and non-infected patients, respectively. HGV-RNA became negative in all treated patients, but sustained viral inhibition was observed only in those with low viral load.

CONCLUSIONS

The prevalence of HGV infection in HCV-infected patients is relatively low in our geographical area. HGV co-infection does not appear to modify the clinical presentation nor the response to interferon in chronic hepatitis C. HGV is sensitive to interferon, particularly if pre-treatment viral load is low.

GBV-C/HGV: a new human hepatitis-related virus

Two novel potentially hepatotropic flavi-like viruses were recently identified in patients with acute or chronic hepatitis and were provisionally called GBV-C and hepatitis G virus (HGV). The sequence identity analysis of these two viruses clearly indicated that GBV-C and HGV are two isolates of the same virus. In addition, the phylogenic analysis of the aligned viral polyprotein sequences showed that the GBV-C and HGV isolates are closely related to two Flaviviruses (GBV-A and GBV-B) that cause hepatitis in tamarins, and are distantly related to hepatitis C virus (HCV). Taken together, these results demonstrate that GBV-C/HGV belongs to the Flaviviridae family. GBV-C/HGV genomic RNA is detectable in both acute and chronic non-A, nonE hepatitis as well as in a minor proportion of patients with fulminant hepatic failure, hepatocellular carcinoma and in blood donors with or without abnormal alanine aminotransferase. However, the majority of patients with prospectively followed HGV infections have no evidence of liver damage. The high frequency of GBV-C/HGV infections in patients who are coinfected with HBV and/or HCV suggests that these viruses can share a common mode of transmission.

Transmission of GB virus C by blood transfusions during heart surgery

BACKGROUND AND OBJECTIVES

Hepatitis-causing viral agents other than those designated A to E are being reported. Their epidemiology, modes of transmission, and infectivity are not yet clear, although they may be transmitted by transfusion.

MATERIALS AND METHODS

Thirty five patients underwent open-heart surgery, receiving an average of 10.2 +/- 10.8 (range 1 to 35) units of blood. The patients were investigated postoperatively for the RNA of the putative non-A-to-E hepatitis virus designated as GB virus C (GBV-C).

RESULTS

Four patients (12%) acquired GBV-C RNA in the serum within 2 to 4 weeks after the operation. GBV-C RNA was detected in at least one of the blood units received by three patients, all of whose units were available for testing, with a sequence in the nonstructural 3 region identical to that from the corresponding patient. Three patients developed elevated alanine aminotransferase levels which persisted for two weeks or longer in two of them.

CONCLUSIONS

GBV-C is transmissible by transfusion and can induce elevated transaminase levels.

Association between fulminant hepatic failure and a strain of GBV virus C

BACKGROUND

The GB virus C (GBV-C) and the hepatitis G virus (HGV) have been detected in patients with acute indeterminant hepatitis and post-transfusion hepatitis. However, the role of the new hepatitis viruses in the aetiology of fulminant hepatitis is little understood. We investigated the presence of GBV-C/HGV in patients with fulminant hepatic failure.

METHODS

Serum samples from 22 German patients with fulminant hepatic failure and 106 symptom-free blood donors (controls) were studied for presence of GBV-C RNA by seminested reverse transcriptase PCR. Primer sequences were derived from the published gene sequences of the conserved NS3 region of the GBV-C prototype and the published isolates. Nucleotide and amino acid sequences of GBV-C-positive isolates, the control RNA, and the published HGV and GBV-C prototype sequences were compared by multiple sequence alignment. We also compared the GBV-C sequences of virus-positive patients who had fulminant hepatic failure with those of 19 patients with chronic hepatitis from our centre. In addition, we searched databases and published papers for further GBV-C helicase sequences in patients with non-fulminant hepatitis.

FINDINGS

GBV-C RNA was detected in 11 (50%) of the 22 patients with fulminant hepatic failure and in five (4.7%) of 106 control-group blood donors. Among the patients with fulminant hepatic failure, six of seven with fulminant hepatitis B and five of ten with fulminant non-A-E hepatitis were positive for GBV-C RNA. Analysis of nucleic acid sequences showed six mutations at defined positions in all 11 patients with fulminant hepatic failure who were positive for GBV-C. None of these mutations were found in the five GBV-C-positive control-group blood donors. Of the six nucleotide changes, four caused no amino acid changes, whereas two mutations at position 100 (G to T) and 102 (T to C) led to an alanine to serine change in the predicted translation product. However, comparison with GBV-C sequences of patients with non-fulminant hepatitis showed that this amino acid mutation was not specific for fulminant hepatic failure. The sequence-motif containing the six nucleotide mutations detected in all patients with fulminant hepatic failure was found in only two of 19 German patients with chronic hepatitis from our centre, and in only one of 88 GBV-C sequences from non-fulminant patients reported by others.

INTERPRETATION

The frequency of GBV-C RNA is higher in fulminant hepatic failure than in any other group of patients with hepatitis, particularly in patients with fulminant hepatitis B or fulminant non-A-E hepatitis. A specific strain of GBV-C may occur in serum of German patients with fulminant hepatic failure.

GB virus C/hepatitis G virus and other putative hepatitis non A-E viruses

The identification of the major agents causing human hepatitis (Hepatitis A, B, C, D and E Viruses) was achieved during the last 30 years. These viruses are responsible for the vast majority of human viral hepatitis cases, but there are still some cases epidemiologically related to infectious agents without any evidence of infection with known virus, designated as hepatitis non A-E. Those cases are considered to be associated with at least three different viruses: 1--Hepatitis B Virus mutants expressing its surface antigen (HBsAg) with altered epitopes or in low quantities; 2--Another virus probably associated with enteral transmitted non A-E hepatitis, called Hepatitis F Virus. Still more studies are necessary to better characterize this agent; 3--Hepatitis G Virus or GB virus C, recently identified throughout the world (including Brazil) as a Flavivirus responsible for about 10% of parenteral transmitted hepatitis non A-E. Probably still other unknown viruses are responsible for human hepatitis cases without evidence of infection by any of these viruses, that could be called as non A-G hepatitis.