Correction to: Occult HBV infection in the oncohematological setting.

The original version of this article unfortunately contained a mistake.

Effect of hepatitis B virus on steatosis in hepatitis C virus co-infected subjects: A multi-centre study and systematic review.

It remains unclear whether hepatitis B virus (HBV) infection may modify the severity of viral steatosis in patients coinfected with chronic hepatitis C virus (HCV). We examined the influence of coinfection with HBV on prevalence of steatosis in chronic hepatitis C in a multi-centre cohort of HBV-HCV subjects, and by performing a systematic review and meta-analysis of the literature. We centrally and blindly assessed steatosis prevalence and severity in a cohort of HBV-HCV coinfected subjects compared to HCV and HBV monoinfected controls and we performed a systematic review of studies addressing the prevalence of steatosis in HBV-HCV subjects compared to HCV controls. In the clinical cohort, we included 85 HBV-HCV, 69 HBV and 112 HCV subjects from 16 international centres. There was no significant difference in steatosis prevalence between the HBV-HCV and the HCV groups (33% vs 45%, P = .11). In subgroup analysis, lean HBV-HCV subjects with detectable HBV DNA had less steatosis than lean HCV subjects matched for HCV viremia (15% vs 45%, P = .02). Our literature search identified 5 additional studies included in a systematic review. Overall, prevalence of steatosis > 5% was similar in HBV-HCV infection compared to HCV (pooled odds ratio [OR] 0.91, 95% CI 0.53-1.6) although there was significant heterogeneity (I2 69%, P = .007). In conclusion, although the prevalence of steatosis is similar in HBV-HCV compared to HCV subjects, our analysis suggests that there may be an inhibitory effect of HCV-induced steatogenesis by HBV in certain subgroups of patients.

Occult HBV infection in the oncohematological setting.

INTRODUCTION: Occult hepatitis B infection (OBI), a virological condition characterized by a low release of Hepatitis B Virus (HBV) from liver cells and low HBV-DNA levels in serum and/or liver tissue of HBsAg-negative subjects, may reactivate in oncohematological patients undergoing immunosuppression by aggressive chemotherapy or hematopoietic stem cell transplantation. The entity of OBI reactivation varies from an increase in HBV replication without liver damage to an active HBV replication followed by liver cell necrosis, frequently severe and in some cases life threatening. Because of a possible severe outcome associated with OBI reactivation (hepatic failure or death due to the discontinuation of chemotherapy), prophylaxis with anti-HBV nucleot(s)ide analogues is recommended in relation to the foreseeable degree of immunosuppression. MATERIALS AND METHODS: This review article focuses on the clinical impact of OBI in the oncohematological setting and is addressed to all health care workers having in care oncohematological patients or involved in the treatment of HBV infection and OBI prophylaxis. CONCLUSION: International guidelines have indicated lamivudine prophylaxis in hematopoietic stem cell transplantation and when high-dose corticosteroids or anti-CD20 or anti-CD52 monoclonal antibodies are used. Entecavir or tenofovir should replace lamivudine for patients with advanced liver diseases for whom reactivation of OBI may be life threatening. When anti-CD20 or anti-CD52 sparing schedules or other non-aggressive chemotherapies are used, monitoring may be indicated, but very early treatment with highly effective antiviral drugs (entecavir or tenofovir) should be administered once a reactivation of OBI has occurred.

Efficacy and safety of tenofovir, entecavir, and telbivudine for chronic hepatitis B in heart transplant recipients.

BACKGROUND: Treatment of chronic hepatitis B (CHB) with polymerase inhibitors is key to prevent disease flares and progression toward advanced liver disease. Efficacy and tolerability of newer agents has been reported anecdotally in transplant recipients. METHODS: In this prospective, observational study, we assessed outcomes of therapy with tenofovir (TDF), entecavir (ETV), and telbivudine (LdT) in 13 heart transplant recipients (HTR) with CHB. RESULTS: Most patients were hepatitis B e antigen negative, had low baseline hepatitis B virus (HBV) DNA, and normal aminotransferases. Liver biopsy showed a median fibrosis score of 1.5 (range 0-4). Glomerular filtration rate (GFR) was <50 mL/min in 7 patients (54%). Two patients were started on de novo ETV before transplant. Eleven previously treated patients were switched to TDF (n = 9) or LdT (n = 2). Median treatment duration was 33 months (range 1-71). HBV DNA remained suppressed in 6 patients and became undetectable in 5. Aminotransferases went down to the normal range in all patients, with a single flare in 1 patient. One patient lost hepatitis B surface antigen. No cases occurred of hepatic decompensation, hepatocellular carcinoma, or liver-related death. The GFR remained largely stable, and no cases of TDF-related hyper-phosphaturia were observed. CONCLUSIONS: This study indicates that newer antivirals are effective and safe in HTR with CHB.

Role of interleukin 28-B in the spontaneous and treatment-related clearance of HCV infection in patients with chronic HBV/HCV dual infection.

The purpose of this investigation was to evaluate the role of IL28-B polymorphism in the clearance of hepatitis C virus (HCV) in chronic hepatitis B virus (HBV)/HCV coinfection during a long-term follow-up. Thirty-four consecutive patients with HBV surface antigen (HBsAg)-positive/anti-HCV-positive chronic hepatitis were retrospectively enrolled at their first liver biopsy (LB). For all patients, a documented clinical, serological and virological follow-up of at least 3 years (range 3-16 years) after LB and a sample of whole blood for genetic evaluation were available. Of the 24 patients with detectable serum HBV-DNA and HCV-RNA at their first observation, three cleared both HBV-DNA and HCV-RNA, 12 HCV-RNA and five HBV-DNA. Of the seven HBV DNA-positive/HCV RNA-negative patients at enrolment, three cleared HBV-DNA and one remained HBV DNA-positive and became HCV RNA-positive. All three HBV DNA-negative/HCV RNA-positive patients remained unchanged. Compared with the 12 patients with HCV persistence, the 15 patients who cleared HCV were younger, had lower serum alanine aminotransferase (ALT), HCV load, and histological activity index (HAI) and fibrosis score, more frequently had IL28-B CC variant, had been receiving an interferon-based treatment and less frequently cleared serum HBV-DNA. To investigate the relationship between the IL28-B variants and clearance of HCV, excluding the confounding effect of interferon-based treatment, the Mantel-Haenszel test was used, which indicated an association between HCV clearance and IL28-B variants (p = 0.009). In chronic HBV/HCV coinfection, a long-term follow-up showed a frequent spontaneous or treatment-related clearance of active replication of one or both viruses and identified the IL28-B CC genotype as an independent predictor of HCV clearance.

Abdominal fat interacts with PNPLA3 I148M, but not with the APOC3 variant in the pathogenesis of liver steatosis in chronic hepatitis C.

The patatin-like phospholipase domain-containing 3 gene (PNPLA3) and the apolipoprotein C3 gene (APOC3) have been studied in relation to liver steatosis and liver disease outcome. The aim of this study was to evaluate the influence of PNPLA3 p.I148M and APOC3 rs2854116 and rs2854117 polymorphisms on the clinical and histological presentation of chronic hepatitis C in an Italian population and their relationship with viral and anthropometric parameters. Patients with hepatitis C (n = 166) entered the study receiving a clinical, histological, virological and biochemical evaluation. APOC3 (rs2854116 and rs2854117) and PNPLA3 (p.I148M) variants were genotyped. PNPLA3 polymorphisms were associated with liver steatosis, which was significantly higher in patients with p.148I/M (P = 0.034) and p.148M/M (P = 0.004) variants than those homozygous for the PNPLA3 wild type. Excluding patients with HCV genotype 3, the association with liver steatosis and PNPLA3 variants was more marked (p.148I/I genotype vs p.148I/M, P = 0.02, and vs p.148M/M, P = 0.005). The APOC3 polymorphism was not associated with any of the evaluated parameters. Among the interacting factors, BMI and waist circumference correlated with liver steatosis (P = 0.008 and 0.004, respectively). Relationship between waist circumference and liver steatosis was analysed for the different PNPLA3 genotypes. Homozygous 148M patients showed a stronger correlation between waist circumference and steatosis than those carrying the other genotypes (P = 0.0047). In our hepatitis C-infected population, the PNPLA3 polymorphism influenced the development of liver steatosis, but not fibrosis progression. APOC3 polymorphisms had no effect on the development of steatosis and no influence on the PNPLA3 polymorphism. The amount of abdominal fat can increase the association of PNPLA3 p.I148M with liver steatosis.

Steatosis is the predictor of relapse in HCV genotype 3- but not 2-infected patients treated with 12 weeks of pegylated interferon-α-2a plus ribavirin and RVR.

HCV genotypes 2- or 3-infected patients with a rapid virological response (RVR) to therapy with pegylated interferon and ribavirins who have a low viral load, noncirrhotic and nonobese may be considered for a shorter course of treatment. However, no studies have assessed host-viral factors associated with relapse in genotype 2 and 3 separately. Accordingly, we assessed whether 12 weeks of pegylated interferon and ribavirin was an optimized regimen for treatment of HCV genotype 2 and 3 with positive predictors of response. Power and sample size were a priori calculated and 96 consecutive chronic hepatitis C patients (53, genotype 2 and 43, genotype 3) without cirrhosis who were not obese and who achieved a RVR to therapy with peg-IFN-α-2a and ribavirin were enrolled. Fibrosis, steatosis, homeostatic model assessment-insulin resistance and HCV RNA were predefined variables to be evaluated in relapse. An intention-to-treat analysis was performed. SVR rates were 98% and 84% for genotype 2 and 3, respectively. Analysis of genotype 3 patients who had relapse showed a negative correlation with steatosis (P < 0.0001) and HCV RNA (P < 0.015). Multivariate analysis showed that steatosis was the independent predictor of relapse (OR, 0.988; 95% CI, 0.981-0.993; P < 0.001). Genotype 3 patients with steatosis had a relapse rate of 36.4% and 15.8% in those with high and low viral load, respectively, whereas there was no relapse in those without steatosis. In conclusion, a 12-week course of therapy is sufficient for patients without cirrhosis, not obese and infected with HCV genotype 2 achieve a RVR. This is not the case for genotype 3. Steatosis is the independent predictor of relapse. New therapeutic strategies are necessary for this subgroup of HCV genotype 3.

Drugs and liver injury: a not to be overlooked binomial in COVID-19.

SARS-CoV-2 infection (COVID-19) results predominantly in pulmonary involvement but a direct, virus-induced liver damage may also occur, whose mechanisms are being actively investigated. Accordingly, it appears of utmost importance to monitor liver function and carefully evaluate hepatic safety of the various drugs administered during COVID-19. In this respect, many drugs, biological agents and novel molecules, whose efficacy in COVID-19 is under scrutiny, have also been shown to potentially cause or worsen liver damage. In this article, we review safety data of established as well as promising agents for COVID-19.

Immunocompromised patients with HBsAg a determinant mutants: comparison of HBsAg diagnostic assays.

Hepatitis B surface antigen (HBsAg) is considered the best marker for the diagnosis of hepatitis B virus (HBV) infection. Mutations of the s gene involving amino acid substitutions within the a determinant could affect the sensitivity of diagnostic tests. In the present study, HBsAg mutants were detected in 3 immunocompromised patients, previously found to be HBsAg negative and anti-HBs positive. All patients had high levels of HBV-DNA, whereas HBsAg tests gave discordant results. Immunosuppression can cause viral reactivation of occult HBV infection in these patients and favour the selection of HBsAg a determinant mutants.

Management of carbapenem-resistant Enterobacteriaceae infections.

BACKGROUND: Carbapenem resistance is defined as in vitro non-susceptibility to any carbapenem and/or documented production of a carbapenemase. This feature has rapidly spread worldwide among clinical isolates of Enterobacteriaceae, mostly Klebsiella spp., and is associated with diverse molecular mechanisms. Carbapenem resistance is often associated with resistance to all traditional ß-lactams and other classes of antibiotics, denoting a typical example of an extensively drug-resistant phenotype. OBJECTIVES: To summarize and interpret in a balanced manner the most clinically relevant data in terms of carbapenem-resistant Enterobacteriaceae (CRE) infection management. SOURCES: Data were extracted by PubMed and clinicaltrials.gov search and manual scrutiny among references of analysed articles. CONTENT: Features of newer and older, rediscovered antimicrobial options for CRE are described. Observational studies and randomized clinical trials (RCT) of CRE treatment are summarized, with a specific focus on the effects of monotherapy compared with combination treatment. IMPLICATIONS: The available evidence on the current management of CRE mostly comes from observational, non-comparative, retrospective, small studies, with a high risk of selection bias. Very little evidence comes from RCT. Conflicting results of RCT and observational studies call for caution before combination therapies are deemed superior to monotherapy. Data on newer agents have spurred enthusiasm but remain limited as concerns severe CRE infections. A balanced approach should guide the clinician in the choice of old or new drugs, and of monotherapies or combination regimens. Efforts should be made to perform adequately sized clinical trials answering well-defined research questions.

Microsomal triglyceride transfer protein (MTP) -493G/T gene polymorphism contributes to fat liver accumulation in HCV genotype 3 infected patients.

SUMMARY: (A) A reduced activity of microsomal triglyceride transfer protein (MTP), a key enzyme of assembly/secretion of lipoproteins, is related to HCV steatosis. Host genetic background may influence development of steatosis. The aim of the study was to investigate the association between MTP-493 G/T gene polymorphism, fat liver accumulation and fibrosis progression in HCV infected patients. A total of 102 naïve patients with liver biopsy proven chronic hepatitis C were evaluated for MTP-493 G/T gene polymorphism, HCV RNA, HCV genotype, HOMA-IR, serum adiponectin, TNF-alpha and serum lipid levels. HCV genotype 3 infected patients carrying the T allele of the MTP gene polymorphism showed higher degree of steatosis than those carrying GG genotype (3.45 +/- 0.37 vs 1.30 +/- 0.45, respectively; P < 0.001). MTP'T' allele carriers also had higher HCV RNA serum levels (P < 0.01) and hepatic fibrosis (P < 0.001). Irrespective of MTP genotype, patients with HCV genotype 3 had lower levels of cholesterol, ApoB, HDL and LDL. In HCV genotype non-3 infected patients no parameters were associated with MTP gene polymorphism. In conclusion the presence of T allele of MTP-493G/T gene polymorphism predisposes patients infested with HCV genotype 3 to develop higher degree of fatty liver accumulation.

Hepatic steatosis and insulin resistance are associated with serum imbalance of adiponectin/tumour necrosis factor-alpha in chronic hepatitis C patients.

BACKGROUND: Steatosis and insulin resistance (IR) have a pathogenic role in chronic hepatitis C (HCV). Adipocytokines balance modulates hepatic lipid content and IR. AIM: To evaluate serum adipocytokines and relationship with virological, histological and metabolic parameters in chronic HCV. METHODS: Adiponectin and tumour necrosis factor-alpha (TNF-alpha) levels, HCV genotypes, HCV-RNA, IR (HOMA-IR), body mass index and liver steatosis and fibrosis were assessed in 161 non-diabetic chronic HCV patients. RESULTS: Chronic HCV patients with steatosis showed lower serum adiponectin levels and higher levels of TNF-alpha, HOMA, alanine aminotransferase, gamma-glutamiltransferase and Histological Activity Index (HAI) and fibrosis scores. Low adiponectin levels were independently associated with grades of steatosis and HOMA-IR. Higher tumour necrosis factor-alpha levels were observed in patients with low adiponectin levels. The extension of steatosis was inversely correlated with adiponectin levels. A correlation between grade of steatosis with HOMA-IR and fibrosis was observed. HCV genotype 3-infected patients showed lower adiponectin levels than those with other genotypes. An independent predictor of low adiponectin levels in genotype 3 infection was the extension of steatosis. Liver fibrosis score was associated with steatosis, HAI and age. CONCLUSIONS: Chronic HCV patients with steatosis showed a serum adiponectin/TNF-alpha imbalance that is associated with IR. Reduced adiponectin levels may be involved in the pathogenesis of steatosis, which in turn accelerates progression of fibrosis in chronic HCV.

Review article: hepatitis C virus-associated steatosis--pathogenic mechanisms and clinical implications.

Steatosis is a common feature of chronic hepatitis C, and may be caused directly by the virus, as in genotype 3 infection, or be associated with host metabolic factors. The interaction of hepatitis C virus core protein with the lipoprotein secretion pathways causes the characteristic alterations of lipid metabolism observed in hepatitis C virus-related steatosis. Several pathogenic mechanisms are likely involved into the pathogenesis of hepatitis C virus-related steatosis, including hyper-homocysteinaemia, hypoadiponectinaemia and insulin resistance. Steatosis is a major determinant of the liver damage progression in chronic hepatitis C (CHC), and negatively affects the response rate to the interferon (IFN)-based anti-viral treatment. Moreover, recent evidence suggests that steatosis may contribute to liver carcinogenesis. Chronic hepatitis C is a recognized risk factor for type 2 diabetes and it could be implicated into the pathogenesis of atherosclerosis. The role of hepatitis C virus (HCV)-related steatosis in these epidemiological associations remains to be determined.

Clinical reactivation during lamivudine treatment correlates with mutations in the precore/core promoter and polymerase regions of hepatitis B virus in patients with anti-hepatitis B e-positive chronic hepatitis.

BACKGROUND: Drug-resistant mutants may emerge in patients with chronic hepatitis B receiving lamivudine therapy. AIM: To evaluate whether different viral mutational patterns may be associated with clinical reactivation during lamivudine treatment in patients with chronic B hepatitis. METHODS: Eight anti-hepatitis B e-positive patients with (group A) and 14 patients without clinical exacerbation (five anti-hepatitis B e-positive, group B1; nine hepatitis B e antigen-positive, group B2) during lamivudine treatment were investigated. RESULTS: 'Polymerase region': M204V/I variants were found in all group A patients, but in none of group B1 (P=0.0007) and in four of nine of group B2 (44%; P=0.02) patients. The L180M substitution was detected in four of eight (50%) of group A and in none of groups B1 and B2. 'Core promoter': the double basic core promoter (A1762T/G1764A) variant was detected in seven of eight (87%) of group A and in one of five (20%; P=0.03) of group B1 and one of nine (11%; P=0.002) of group B2 patients. 'Precore': the G1896A stop codon mutation was present in seven of eight (87%) of group A and in zero of five (P=0.004) of group B1 and one of nine (11%; P=0.002) of group B2. CONCLUSIONS: Different mutational patterns were observed in the lamivudine-treated patients with and without exacerbation. There was an association of the basic core promoter and stop codon mutations with lamivudine resistance in patients with disease exacerbation.

The impact of the CB2-63 polymorphism on the histological presentation of chronic hepatitis B.

The impact of the cannabinoid receptor 2 (CB2) rs35761398 polymorphism on chronic hepatitis B (CHB) was evaluated in 106 consecutive biopsy-proven CHB patients naive for antiviral therapy. A histological activity index (HAI) > 8 (Ishak scoring) was more frequent in patients with CB2-63 RR than in those with CB2-63 QR or QQ (37% vs. 16.7%, p < 0.05). The logistic regression analysis identified CB2-63 RR (p < 0.05) and a fibrosis score >3 (p < 0.005) as independently associated with an HAI >8. The observation that the CB2-63 RR variant is an independent predictor of extensive necroinflammation opens up new prospects in the study of CHB.

Effects of long-term course of alpha-interferon in patients with chronic hepatitis C associated to mixed cryoglobulinaemia.

OBJECTIVE: To evaluate the efficacy of a long-term course of alpha-interferon (alpha-IFN) in the treatment of HCV-related mixed cryoglobulinaemia and to determine the impact of cryoglobulinaemia on therapeutic response to IFN in chronic hepatitis C (CHC) patients. DESIGN: Prospective controlled study. SETTING: University Medical Centre. PARTICIPANTS: Ninety consecutive CHC patients, 50 with cryoglobulinaemia (25 symptomatic and 25 asymptomatic; median cryocrit, 8%; chronic persistent hepatitis (CPH) 7, chronic active hepatitis (CAH) 27, cirrhosis 16) and 40 without cryoglobulinaemia (CPH 6, CAH 20, cirrhosis 14). HCV genotypes in the cryoglobulinaemic and non-cryoglobulinaemic groups were: 1b 40% and 45%; 2a 40% and 30%; others 20% and 25%, respectively. INTERVENTIONS: Twelve-month course of alpha-IFN 2a, 3 MU, three times weekly. MAIN OUTCOME MEASURES: Disappearance of cryoglobulinaemia and related syndrome, clearance of serum HCV RNA and normalization serum transaminase levels at the end of treatment (response) and after 12 months follow-up (sustained response). RESULTS: Overall, cryoglobulinaemic patients showed a similar response to IFN to those without cryoglobulinaemia (44% vs. 42.5%, respectively). In the cryoglobulinaemic group, symptomatic patients showed a lower response rate than asymptomatic patients (28% vs. 60%, respectively; P<0.05). HCV genotype 2a/c, absence of cirrhosis and a low cryocrit (<9%) were predictive factors of high response rate to IFN. Sustained response in non-cryoglobulinaemic patients (22.5%) tended to be higher than in patients with symptomatic cryoglobulinaemia (4%), as well as among patients carrying genotype 2a/c (67% vs. 10%, respectively; P<0.02). IFN was effective in controlling purpura (80%) but was moderately effective on severe haematuria/proteinuria, renal insufficiency and neuropathy. CONCLUSIONS: A 12-month course of alpha-IFN is effective treatment for HCV-related cryoglobulinaemia. However, patients with CHC associated to symptomatic cryoglobulinaemia have a lower response rate to IFN.

[Role of hepatitis C virus in mixed cryoglobulinemia in patients with chronic hepatitis]. / Ruolo del virus dell'epatite C nella crioglobulinemia mista in pazienti con epatite cronica.

To evaluate the role played by hepatitis C virus (HCV) in mixed cryoglobulinemia in subjects with chronic hepatitis, we studied 72 consecutive patients: 43 had HCV-related chronic hepatitis, 19 HBV-related chronic hepatitis, and 10 chronic hepatitis of other etiology. We used second generation ELISA and RIBA to test for mixed cryoglobulinemia and anti-HCV antibodies in both serum and cryoprecipitates; HCV RNA were evaluated by "nested" PCR. Serum levels of rheumatoid factor and complement were also determined. The immunoglobulins in the cryoimmunoprecipitate were characterized by immunofixation electrophoresis. Cryoglobulinemia was present in 47% of the patients with chronic hepatitis C but in none of the sera of patients with HBV-related chronic hepatitis nor in those with chronic hepatitis of non-viral etiology. Type II mixed cryoglobulinemia was observed in 45% of the cases, and type III in 55%. HCV RNA and anti-HCV antibodies were present in all the cryoimmunoprecipitates. Ninety-five percent of the cryoglobulinemic patients had serum rheumatoid factor and 80% of them had low serum levels of C4. Our data indicate that mixed cryoglobulinemia is frequently associated with HCV-related chronic hepatitis, and that HCV and anti-HCV antibodies play an essential role in the development of mixed cryoglobulinemia.

Three-phase sequential combined treatment with lamivudine and interferon in young patients with chronic hepatitis B.

Alpha-interferon (IFN) or lamivudine monotherapy are ineffective in treating chronic HBeAg positive patients with high viral load and low alanine aminotransferase (ALT) levels. We investigated whether priming lamivudine treatment might enhance the antiviral and immunostimulant action of lamivudine/IFN combination in young tolerant patients. Eleven chronic HBeAg positive patients received: 100 mg/day lamivudine for 3 months followed by IFN 5 MU/m2/tiw with lamivudine 100 mg/day for 6 months and then lamivudine alone 100 mg/day for 9 months. Quantitative hepatitis B virus (HBV)-DNA was evaluated during treatment and core-promoter, precore and polymerase HBV mutants were detected by direct sequencing at the end of therapy. Serum HBV-DNA levels dropped during lamivudine monotherapy and in combination with IFN. After IFN withdrawal, viraemia transiently increased to high levels in five of 11 (45%) patients who showed rt M204V/I lamivudine mutant resistant. Two patients cleared HBeAg without anti-HBe seroconversion. One patient presented core-promoter (A1762T/G1764A) and precore stop codon mutations. Hence, three-phase sequential combined lamivudine/IFN treatment reduced HBV-DNA serum level, but did not lead to HBeAg and HBV-DNA clearance in these highly viraemic, normal ALT patients. Lamivudine/IFN combination did not prevent the emergence of YMDD lamivudine resistance. New schedules of antiviral treatments must be evaluated in this population at risk of disease progression.

Natural history and molecular biology of hepatitis G virus/GB virus C.

BACKGROUND: The hepatitis G virus (HGV) or GB virus C (GBV-C) is a new member of the Flaviviridae family. The virus is transmitted by transfusion of blood, infusion of some blood products, and by parenteral exposure to blood during intravenous drug use (IVDU) and haemodialysis. Transmission from mother to infant and by sexual contact has also been documented. Although the virus has been found in patients with acute and chronic hepatitis, evidence of disease association has not been forthcoming. The majority of patients carry the virus in the absence of liver enzyme abnormalities. OBJECTIVES: To review what is currently known about HGV/GBV-C in order to evaluate its similarity with other members of the Flaviviridae and the association of the virus with disease. RESULTS: The genomic organisation of the virus is typical for Flaviviridae, with long 5' and 3' untranslated regions (UTR). However, a clearly identifiable nucleocapsid encoding region is lacking. Polyprotein synthesis is mediated through an internal ribosome entry site (IRES) contained within the 5' UTR. Phylogenetic tree analysis of sequences derived from this region has demonstrated the existence of at least three genotypes. Apart from serum, HGV-RNA has been detected in lymphocytes also, but the quasispecies present in the two compartments appear to be different. The envelope glycoprotein E2 lacks a hypervariable region and is potentially the target of a neutralising antibody response. CONCLUSION: Molecular analysis of HGV reveals close similarity of the virus with HCV. However, an association of the virus with liver disease remains unresolved and no association of the virus with hepatocellular carcinoma has been reported.