TT virus and hepatitis G virus infections in Korean blood donors and patients with chronic liver disease

Review of human pegivirus: Prevalence, transmission, pathogenesis, and clinical implication

Human pegivirus (HPgV-1), previously known as GB virus C (GBV-C) or hepatitis G virus (HGV), is a single-stranded positive RNA virus belonging to the genus Pegivirus of the Flaviviridae family. It is transmitted by percutaneous injuries (PIs), contaminated blood and/or blood products, sexual contact, and vertical mother-to-child transmission. It is widely prevalent in general population, especially in high-risk groups. HPgV-1 viremia is typically cleared within the first 1–2 years of infection in most healthy individuals, but may persist for longer periods of time in immunocompromised individuals and/or those co-infected by other viruses. A large body of evidences indicate that HPgV-1 persistent infection has a beneficial clinical effect on many infectious diseases, such as acquired immunodeficiency syndrome (AIDS) and hepatitis C. The beneficial effects seem to be related to a significant reduction of immune activation, and/or the inhabitation of co-infected viruses (e.g. HIV-1). HPgV-1 has a broad cellular tropism for lymphoid and myeloid cells, and preferentially replicates in bone marrow and spleen without cytopathic effect, implying a therapeutic potential. The paper aims to summarize the natural history, prevalence and distribution characteristics, and pathogenesis of HPgV-1, and discuss its association with other human viral diseases, and potential use in therapy as a biovaccine or viral vector.

Human pegivirus type 1 infection in Asia-A review of the literature

The human pegivirus type 1 (HPgV-1)-as known as hepatitis G virus and GB virus C-is a common single-stranded RNA flavivirus. Because few studies have demonstrated an association between HPgV-1 infection and disease, screening for HPgV-1 is not performed routinely. Nonetheless, a beneficial impact of HPgV-1 infection on HIV disease progression has been reported in multiple studies. Given the burden of HIV in Asia and the complex interactions between viral co-infections and the host, we provide a comprehensive overview of the existing data from Asia on HPgV-1 infection, including the prevalence and circulating genotypes in all Asian countries with data reported. This review highlights the research conducted thus far and emphasizes the need for additional studies on HPgV-1 across the Asian continent.

Global prevalence of human pegivirus-1 in healthy volunteer blood donors: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

The local prevalence of HPgV-1 has been reported from different countries worldwide, but the global prevalence of HPgV-1 remains unknown. The aim of this systematic review and meta-analysis was to gather data from the literature to estimate the prevalence of HPgV-1 in healthy volunteer blood donors in the world.

MATERIALS AND METHODS

We searched PubMed, EMBASE, Scopus and Google Scholar databases for records up to January 2019 and included studies reporting HPgV-1 virus prevalence amongst healthy volunteer blood donors based on the detection of HPgV-1 RNA.

RESULTS

In all, we included 79 studies for the systematic review and 63 for the meta-analysis. Based on the random effect meta-analysis of 35 468 volunteer blood donors, we found the global prevalence of HPgV-1 to be 3·1% (95% CI, 2·4-4·1). The pooled prevalences of HPgV-1 were 1·7% (95% CI, 1·1-2·6) in North America, 9·1% (95% CI, 6·4-12·7) in South America, 2·3% (95% CI, 2%, 2·8) in Europe and 2·4% (95% CI, 1·4-4) in Asia. Subgroup analyses based on age, gender or risk factors were not possible.

CONCLUSION

Approximately 3 in 100 blood donations worldwide are positive for HPgV-1 increasing the risk of infection from transfusion of their components to subsequent recipients. Further research on virus pathogenicity is required before recommending routine screening of HPgV-1 for healthy volunteer blood donors.

Metagenomics analysis of red blood cell and fresh-frozen plasma units

BACKGROUND

Although the risk of transmitting infectious agents by blood transfusion is dramatically reduced after donor selection, leukoreduction, and laboratory testing, some could still be present in donor's blood. A description of metagenomes in blood products eligible for transfusion represents relevant information to evaluate the risk of pathogen transmission by transfusion.

STUDY DESIGN AND METHODS

Detection of viruses, bacteria, and fungi genomes was made by high-throughput sequencing (HTS) of 600 manufactured blood products eligible for transfusion: 300 red blood cell (RBC) and 300 fresh-frozen plasma (FFP) units.

RESULTS

Anelloviruses and human pegivirus, frequent in the blood of healthy individuals, were found. Human papillomavirus type 27 and Merkel cell polyomavirus, present on the skin, were also detected. Unexpectedly, astrovirus MLB2 was identified and characterized in a FFP unit. The presence of astrovirus MLB2 was confirmed in donor's blood and corresponded to an asymptomatic acute viremia. Sequences of bacteria and fungi were also detected; they are likely the result of environmental contamination.

CONCLUSION

This study demonstrates that HTS is a promising tool for detecting common and less frequent infectious pathogens in blood products.

Association between Hepatitis G and Unknown Chronic Hepatitis

Background:

Hepatitis G virus (HGV) is a hepatotrope virus with unknown importance. The genome of the virus has been detected in patients with acute or chronic non-A-E hepatitis, cirrhosis, and hepatocellular carcinoma. The aim of this study was to determine the association between hepatitis G and unknown chronic hepatitis.

Methods:

This case-control study was performed in Ebne-Sina military hospital in Hamadan, Iran. The cases were 35 military staff with unknown chronic hepatitis. The control group consisted of 59 healthy subjects who had normal levels of serum alanine aminoteransferase (ALT). The data were analyzed by SPSS, version18, using Fisher’s exact test, the Student’s t-test, and multivariate logistic regression analysis.

Results:

Only one patient in the case group (2.9%) tested positive for HGV antibodies, and no one was infected in the control group. There was no association between HGV infection and unknown chronic hepatitis in our study (P=0.37). A significant association was found between the male gender and unknown chronic hepatitis (OR=14.9, P=0.01).

Conclusion:

No association between HGV infection and unknown chronic hepatitis was found in our study, so it was not necessary to evaluate these patients for HGV infection.

Hepatitis viruses (other than hepatitis B and C viruses) as causes of hepatocellular carcinoma: an update

Chronic hepatitis B and C virus infections are universally accepted as causes of hepatocellular carcinoma in humans. Hepatitis A and E viruses cause only acute self-limiting infections of the liver. Of the remaining hepatitis viruses - Delta hepatitis, hepatitis G (GB-C), TT and SEN - all have at some time been incriminated as causes of hepatocellular carcinoma. Delta hepatitis virus requires helper functions from hepatitis B virus to become invasive. Chronic Delta/hepatitis B viral co-infection runs a more severe course than that resulting from chronic hepatitis B virus infection alone, with progression to cirrhosis being more likely and more rapid. A substantial majority of the early studies did not find an increased incidence of hepatocellular carcinoma in co-infected individuals. But more recently, an increased incidence of the tumour has been recorded more often than no increase. Further studies are needed to draw a firm conclusion with regard to the hepatocarcinogenic effect of dual Delta/hepatitis B virus co-infection. With one exception, no published study (of 13) has incriminated chronic infection with hepatitis G virus as a cause of hepatocellular carcinoma. The dissenting study, published in 1999, was the only one performed in the United States. Fewer studies of the hepatocarcinogenic effect of TT virus have been performed. Apart from one study, published in 1999, no convincing evidence is available that supports a causal role for TT virus in hepatocarcinogenesis. The exception was in Japanese patients with high hepatitis C viral loads but independent of chronic hepatitis C virus infection. No evidence has been produced to indicate that SEN virus causes hepatocellular carcinoma.

Detection of TT virus in HIV-1 exposed but uninfected individuals and in HIV-1 infected patients and its influence on CD4+ lymphocytes and viral load

The TT virus (TTV) was detected for the first time in the serum of a patient with post-transfusion hepatitis of unknown origin. TTV was subsequently, also found in the serum of blood donors with no history of blood transfusion. In the present study, the percentage of TTV carriers among HIV-infected and noninfected patients was determined. The study was conducted to evaluate CD4 count and HIV viral load in 100 asymptomatic patients infected with HIV-1, 100 symptomatic patients with AIDS, 100 HIV-1 exposed but uninfected individuals and 100 normal healthy blood donors. In this work, the presence of TTV was investigated by nested-PCR. TTV was detected in 6% of normal donors, 12.5% of HIV-infected individuals and 21% of exposed individuals. The presence of TTV was statistically significant in the HIV-exposed individuals (21/100) compared with blood donors (6/100). Odds ratio=4.16 (95%CI 1.60-10.83). No inter-group relations were found for CD4 and CD8 counts or HIV viral load. In the symptomatic group, patients with TTV presented minor viral load. This work demonstrated that TTV was detected in HIV-exposed individuals and no relation was verified for CD4, CD8 and viral load in the asymptomatic and symptomatic HIV patients.

Transfusion-transmitted infections

Although the risk of transfusion-transmitted infections today is lower than ever, the supply of safe blood products remains subject to contamination with known and yet to be identified human pathogens. Only continuous improvement and implementation of donor selection, sensitive screening tests and effective inactivation procedures can ensure the elimination, or at least reduction, of the risk of acquiring transfusion transmitted infections. In addition, ongoing education and up-to-date information regarding infectious agents that are potentially transmitted via blood components is necessary to promote the reporting of adverse events, an important component of transfusion transmitted disease surveillance. Thus, the collaboration of all parties involved in transfusion medicine, including national haemovigilance systems, is crucial for protecting a secure blood product supply from known and emerging blood-borne pathogens.

Current status of hepatitis C virus infection in Korea

Chronic liver disease, including liver cirrhosis and hepatocellular carcinoma (HCC), has been a major cause of mortality in Korea. The prevalence rates of hepatitis C virus (HCV) and hepatitis B virus (HBV) infections in the general population of Korea are approximately 1 and 5%, respectively. The most common genotypes of HCV in Korea are 1b and 2a. The sustained virological response rates after antiviral therapies, including combined interferon-alpha and ribavirin, have been reported to be 38-59%. The annual incidence of HCC among HCV-related liver cirrhosis has been estimated at 5%, and approximately 12% of HCC is attributable to HCV and 68% to HBV in Korea. The mean age of patients with HCV-related HCC at the time of diagnosis was consistently 10 years older than that of patients with HBV-related HCC. Moreover, HCV-related HCC was accompanied by more advanced liver cirrhosis than HBV-related HCC. Coinfection with HBV seemed to increase the risk of developing HCC in chronic HCV infection. After the successful program of hepatitis B vaccination, HCV infection is now emerging as an important etiology of chronic liver disease in Korea, which warrants more detailed and large-scale studies.

Hepatitis G Virus: Prevalence in Blood Donors in Armed Forces

BACKGROUND

A new RNA virus designated hepatitis G virus (HGV) was recently identified. Because HGV has less than 25% sequence or amino acid homology with hepatitis C virus (HCV) and other established Flaviviridae, it is considered to be a new genus in this growing family of hapatotropic viruses. Hepatitis G virus has been associated with hepatitis and is transmitted through parenteral and sexual route.

MATERIAL AND METHODS

A study comprising 500 healthy voluntary blood donors (service personnel) was under taken to find out prevalence of HGV. HGV RNA was detected by reverse transcriptase - polymerase chain reaction (RT-PCR). Hepatitis B surface antigen (HbsAg) and antibody to HCV were detected by Enzyme Linked Immunosorbent Assay (ELISA).

RESULTS

Thirteen donors (2.6%) were positive for HGV RNA. 17 donors (3.4%) were positive for antibody to hepatitis C virus (HCV) by ELISA. Co-infection of HGV with hepatitis B virus (HBV) was seen in 5 donors and with HCV infection in 2 donors. Co-infection of HGV, HBV and HCV was not seen in any donor.

CONCLUSION

So far there is no conclusive evidence that HGV produces hepatitis. But presence of HGV in hepatitis cases casts a doubt on this finding. Prevalence rate in blood donors may be helpful in future studies when the exact role of HGV is known.

Effect of HBeAg on the hepatitis B virus vertical transmission in neonates

AIM: To investigate the effect of HBeAg on the hepatitis B virus vertical transmission in neonates.

METHODS: HBsAg positive pregnant women were enrolled,and ELISA or Abbott was employed to detect the HBeAg and HBsAg in the peripheral blood of neonates and their mothers.

RESULTS: Fifty-seven HBsAg positive pregnant women were reconfirmed as HBsAg positive. Fifteen of them were detected as HBeAg positive. Eleven of 16 neonates born to 15 HBeAg positive mother were detected as HBeAg positive. Three neonates diagnosed as HBsAg positive by ELISA or Abbott reagents were detected as HBeAg positive. Statistic analysis indicated that HBeAg in newborns was an important risk factor.

CONCLUSION: HBeAg in neonates played an important role during HBV vertical transmission.

Expression of PCNA and CD44mRNA in colorectal cancer with venous invasion and its relationship to liver metastasis

AIM: To investigate the expression of proliferating cell nuclear antigen (PCNA) and CD44mRNA in colorectal cancer with venous invasion and its relationship with liver metastasis.

METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression of PCNA and CD44mRNA in 31 cases of colorectal cancer with venous invasion.

RESULTS: Positive expression rates of PCNA and CD44mRNA in colorectal cancer were higher than those without liver metastasis (P < 0.05 and P < 0.01). In case of colorectal cancer with liver metastasis, strongly positive rates of PCNA and CD44mRNA were 94.1% and 70.6%, respectively, significantly higher than those without liver metastasis. There was a positive relationship between the expressions of PCNA and CD44mRNA (r = 0.67, P < 0.05).

CONCLUSION: Detection of PCNA and CD44mRNA expression in colorectal cancer may be useful for evaluating liver metastasis of cancer cells.