Significance of extrahepatic replication of hepatitis B virus

Self-limited HBV infection of the recipient does not reactivate after liver transplantation: Observations from a 30-year liver transplant program

BACKGROUND

A self-limited hepatitis B infection can reactivate in patients under immunosuppression or chemotherapy (reappearance of hepatitis B surface antigen (HBsAg) or HBV-DNA). Exact circumstances of HBV reactivation in patients undergoing liver transplantation (LT) for end-stage liver diseases (ESLD) unrelated to HBV are unknown, and recommendations on HBV prophylaxis remain unclear.

PATIENTS AND METHODS

Among 1273 liver transplants, 168 patients with a self-limited HBV hepatitis B infection prior to LT were identified from our prospective liver transplant database. Patients with underlying chronic HBV infection and recipients of an anti-HBc-positive liver were not included in the analysis. Demographic, laboratory, serological, and virological data were analyzed retrospectively. Appearance of HBsAg or HBV-DNA was defined as reactivation.

RESULTS

The median follow-up after LT was 12.0 years (0.6-30.7 years). The rate of HBV reactivation was 0% independent of antiviral prophylaxis (n = 7; 4.2%), the etiology of ESLD, hepatitis C treatment, or the anti-HBs concentration. The overall patient survival with a history of a self-limited HBV infection before LT did not significantly differ from the rest of the cohort.

CONCLUSION

Antiviral treatment with nucleos(t)ide analogues post-liver transplantation in order to prevent HBV reactivation in patients with a resolved self-limited hepatitis B infection prior to LT seems to be omittable since the main viral reservoir is removed by the hepatectomy. These findings may clarify the current uncertainty in the recommendations regarding the risk of HBV reactivation in patients with self-limited hepatitis B prior to LT.

Role of nucleoside/nucleotide analogues and low-dose hepatitis B immune globülin in prophylaxis of hepatitis B recurrence among cadaveric liver transplant recipients

BACKGROUND/AIMS

Hepatitis B core antibody (HBcAb) positivity of the donor or the recipient may pose a risk of hepatitis B virus (HBV) reactivation following liver transplantation (LT). We retrospectively investigated patient survival and reactivation among recipients who were given low-dose Hepatitis B Immune Globulin (HBIG) plus antiviral agent (AV) versus AV only.

MATERIALS AND METHODS

Records of cadaveric LT recipients, between 2013 and 2016, with positive Hepatitis B surface Antigen (HBsAg) and/or HBcAb and recipients who had received LT from HBcAb-positive donors were reviewed. Patient characteristics and clinical data were extracted. Donor variables were retrieved from the United Network of Organ Sharing (UNOS) database. HBIG (1560 IU/mL) Intravenous (IV) was intraoperatively administered with three daily doses. Entecavir 1 mg daily was also given. STATA was used for statistical analysis.

RESULTS

There were 53 recipients; 39 (73.6%) were male with a median age of 59 y. HCV was the major indication in 30 (55.6%) patients. There were 28 recipients (52.8%) who received HBIG plus AV and 25 (47.2%) received AV only. The Model of End Stage Liver Disease (MELD) score between the groups were similar. Survival rates at 6, 12, and 24 months were 100% (n=53), 93.2% (n=44), and 100.0% (n=26), respectively. There was no reactivation; two recipients in the AV group and one in the HBIG plus AV group died within 12 months.

CONCLUSION

This study supports the use of low-dose HBIG and AV for post-LT prophylaxis to be as effective as conventionally used high-dose HBIG (9600 IU) plus AV. Future prospective larger studies are warranted to examine the potential benefits of using AV alone without HBIG.

Prophylaxis of hepatitis B infection in solid organ transplant recipients

Rates of transmission of hepatitis B virus (HBV) infection from organ donors with HBV markers to recipients along with reactivation of HBV during immunosuppression following transplantation have fallen significantly with the advent of hepatitis B immune globulin (HBIg) and effective antiviral therapy. Although the availability of potent antiviral agents and HBIg has highly impacted the survival rate of HBV-infected patients after transplantation, the high cost associated with this practice represents a major financial burden. The availability of potent antivirals with high genetic barrier to resistance and minimal side effects have made it possible to recommend an HBIg-free prophylactic regimen in selected patients with low viral burden prior to transplant. Significant developments over the last two decades in the understanding and treatment of HBV infection necessitate a re-appraisal of the guidelines for prophylaxis of HBV infection in solid organ transplant recipients.

Hepatitis B recurrence after liver transplantation: a single center experiences and review the literature

BACKGROUND

Despite the advances in the treatment of chronic hepatitis B virus (HBV) infection, liver transplantation (LT) remains the only hope for many patients with end-stage liver diseases resulting from HBV.

OBJECTIVES

The aim of this study was to investigate the rate of HBV recurrence in cases that had undergone LT due to the HBV related liver cirrhosis.

PATIENTS AND METHODS

Forty-nine patients who underwent LT due to HBV related cirrhosis since 2001 to 2009 in Shiraz Organ Transplantation Center were enrolled in the present study. They were asked to complete the planned questionnaire and also to sign the informed consent in order to take part in this study. Post-transplant prophylaxis protocol against HBV recurrence was based on a hundred milligrams of lamivudine daily plus intramuscular injections of hepatitis B immune globulin (HBIG) with appropriate dosage to keep anti-HBs antibody titer above 300 IU/L and 100 IU/L in the first six months and afterwards, respectively. Blood samples were obtained and checked for HBsAg, HBeAg, and the titers of Anti -HBsAb as well as Anti- HBeAb with ELISA. A quantitative HBV DNA assay was also done on all samples (GENE-RAD® Real-time PCR).

RESULTS

There were 91.8% males and 8.2% females enrolled in the study. The duration of post-transplant prophylaxis ranged from 3 months to 8 years (mean 18.9 ± 19.3 months). HBsAg and HBeAg were positive in 24.5% and 2% of cases, respectively. Real-time PCR for HBV DNA were zero copies/mL in 91.8% of patients, none of which represented a positive value for HBV recurrence (Positive > 10,000 copies/mL). The mean Anti-HBs Ab titer was 231.7 ± 135.9 IU/L; it was above 100 IU/L in 71.4% of patients. Thirty-seven (75.5%) of the patients were taking tacrolimus plus mycophenolate mofetil, 6 (12.2%) were on cyclosporine plus mycophenolate mofetil, and 6 (12.2%) were taking sirolimus plus mycophenolate mofetil. HBsAg was detectable in seven patients taking tacrolimus plus mycophenolate mofetil (18.9%), in four patients taking cyclosporine plus mycophenolate mofetil (66.7%), and in one patient among the six who were taking sirolimus plus mycophenolate mofetil (16.7%). There was no significant statistical correlation between the presence of a positive value for HBsAg and the immunosuppression regimen or Anti HBsAb titer (P ˃ 0.05). Presence of a positive value for HBsAg was not predictive of a positive HBV DNA or its level in blood (P ˃ 0.05).

CONCLUSIONS

Post-transplant HBV prophylaxis with lamivudine and intramuscular HBIG with appropriate dosage to keep anti-HBs antibody titer above 300 IU/L in the first six months and above 100 IU/L afterwards is effective for prevention of HBV recurrence after LT.

Hepatitis B immunoglobulin in preventing reinfection following liver transplantation

Before the availability of hepatitis B immunoglobulin (HBIG) in hepatitis B-positive transplant recipients, the acute mortality was very high, in many centers up to 50% within 60 days post-transplant. The overall reinfection rate was approximately 60% within the initial 6 months, increasing to 80-90% within the initial 12 months and, in many cases, leading to allograft loss and death or retransplantation. These recurrent infections were often more severe and more rapidly progressing than the initial infection, probably due to high-dose immunosuppressive regimens. The poor prognosis before introduction of HBIG made hepatitis B liver disease an absolute contraindication for liver transplantation, leaving these patients with very limited treatment options. This changed in the late 1980s with the introduction of HBIG, which reduced the incidence of hepatitis B in the transplanted liver to approximately 15-50%, with concomitant improvement in graft and overall survival. The prognosis was further improved by a combination of long-term HBIG and antiviral therapy, in particular lamivudine, which reduced the reinfection rate, in most cases to between 0 and 5%. Owing to the cost and relative inconvenience of HBIG, some transplant centers have experimented with early discontinuation of HBIG and replacement with antiviral monotherapy. A number of studies, however, have found significantly higher recurrence rates associated with lamivudine monotherapy (40-50%) compared with combination therapy and, hence, lamivudine monotherapy is not recommended.

Successful Lamivudine Monotherapy in an Elderly Patient Suffering from HBV-Related Decompensated Cirrhosis Associated with Widespread Leukocytoclastic Vasculitis

Hepatitis B virus (HBV) infection is known to be responsible for both hepatic and extrahepatic manifestations including dermatitis, polyarthralgias and arthritis, pulmonary disease, aplastic anemia, glomerulonephritis and vasculitis. The mechanism of these extrahepatic disorders is thought to be linked to immune complex disease, but their pathogenesis is poorly clarified. Immunosuppressive treatment could promote viral load and impair hepatic disease, also worsening the vasculitis by enhancing viral antigenemia. Lamivudine is a nucleoside analogue approved for treating chronic hepatitis B, that decreases the amount of viral antigens by suppressing HBV replication. Several reports have suggested lamivudine in the treatment of vasculitis associated with HBV infection, but, although significant inhibition of HBV is achieved in the short term, resistance develops in 15–32% annual risk rating. We report an elderly patient whose chronic hepatitis B decompensated cirrhosis with associated refractory hepatic hydrothorax and extensive leukocytoclastic vasculitis was successfully treated with ongoing long-term lamivudine monotherapy.

Detection of hepatitis B surface antigen, hepatitis B core antigen, and hepatitis B virus DNA in parotid tissues

OBJECTIVE

To examine the presence of hepatitis B surface antigen (HBsAg), hepatitis B core antigen (HBcAg), and hepatitis B virus (HBV) DNA in parotid tissues from patients with positive serum HBV markers.

METHODS

HBsAg and HBcAg were examined in parotid biopsy tissues from patients with suspected parotid tumor and positive serum HBV markers by immunocytochemistry, and HBV DNA was detected in parotid tissues by PCR.

RESULTS

Among the 22 patients with a parotid tumor, only one was pathologically confirmed as a neoplasm; all others were benign. HBsAg and HBcAg were present in parotid cells with positive rates of 45.5% (10/22) and 40.9% (9/22), respectively, with an overall positive rate of 54.5% (12/22). Of the 22 cases with serum markers of HBV infection, seven (31.8%) had both HBsAg and HBcAg in the parotid cells. HBV DNA was present in seven of the 12 samples in which hepatitis B antigen was detected (58.3%).

CONCLUSIONS

HBV in saliva might originate from the infected salivary glands and the infectious saliva could transmit HBV.

Prevention of hepatitis B virus recurrence after liver transplantation

Liver transplantation for hepatitis B virus (HBV)-related liver disease has changed from a contraindication to outcomes comparable with non-HBV-related liver transplantations during the last two decades. Mainly the implementation of immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and the use of nucleoside analogs such as lamivudine and adefovir account for this dramatic change. The standard of care in most centers today consists of lamivudine treatment in replicating hepatitis B pre-orthotopic liver transplantation (OLT) and a combination regimen of lamivudine and HBIG post-OLT. With adefovir, a potent antiviral drug became available in recent years that allows for the treatment of patients with lamivudine-resistant tyrosine-methionine-aspartate-aspartate (YMDD)-mutant HBV. In the transplantation setting, first studies indicate that a triple prophylactic therapy consisting of lamivudine, adefovir, and HBIG will become the standard of care for YMDD-mutant-related hepatitis B. With new drugs emerging for the treatment of chronic HBV, there is optimism for new options also in the transplant setting.

Is Hepatitis B Immunoglobulin Prophylaxis Needed for Liver Transplantation in the Era of New Antivirals?

Chronic infection with hepatitis B virus (HBV) is one of the most common causes of cirrhosis of the liver and hepatocellular carcinoma worldwide, frequently requiring liver transplantation. Other nonliver organ transplants get infected de novo or through reactivation from previous active or inactive infections. With significant improvements in the surgical techniques and immunosuppressive regimens over the last 20 years, organ transplantation has become the most effective and lifesaving therapy for patients with chronic renal failure, cirrhosis, hepatocarcinoma, and heart failure. Until recently chronic HBV infection was considered a formal contraindication for liver transplantation, since recurrence of infection without prophylaxis occurs in 75% to 90% of the patients, with significant morbidity and mortality and few therapeutic alternatives. However, the introduction of hepatitis B immunoglobulin (HBIG) a decade ago to reduce the risk of reinfection of liver grafts, and more recently the availability of nucleoside analogues with few side effects and easy administration, have led to a dramatic improvement in patient outcomes with a risk of long-term HBV reinfection of less than 10% with combined HBIG and lamivudine prophylaxis. Chronic HBV infection in kidney, heart, and other organs has become a serious long-term problem and one of the most frequent and important comorbidities affecting graft and patient survival. Fortunately the introduction of nucleoside analogues allows significant control of viral replication and prevents progression of liver disease and other organ damage. In the present article we discuss the current indications for HBV prophylaxis and treatment prior to and after organ transplantation, as well as the most cost-effective way to apply different regimens to reduce side effects and improve survival and quality of life after transplantation.

Hepatitis B virus replication in damaged endothelial tissues of patients with extrahepatic disease

Hepatitis B virus (HBV) infection may be complicated by extrahepatic manifestations such as polyarteritis nodosa (PAN), glomerulonephritis, polymyositis, and dermatitis, but the etiology of these processes is not yet clear. HBV replication has been demonstrated in a variety of extrahepatic tissues and cell types, but the possible pathogenetic role of extrahepatic HBV replication has not been fully explored in patients with extrahepatic manifestations of HBV infection. In this case series, immunohistochemistry and in situ hybridization studies were performed on extrahepatic tissues from one HBsAg-positive patient with PAN and another HBsAg-positive patient with polymyositis, using HBsAg-seronegative control subjects with the same vasculitic disorders as controls. Tissue samples from the two study patients had detectable HBV RNA, replicative intermediates of HBV DNA, as well as HBsAg and HBcAg localized to vascular endothelium. In contrast, HBsAg-negative control patients had no tissue reactivity. Our results suggest that patients with HBV-related extrahepatic disease have evidence of viral replication in damaged extrahepatic endothelial tissues. While further studies would be required to support a hypothesis of causality, these findings suggest a role for both immune complex deposition and viral replication within diseased endothelial tissue in the pathogenesis of these poorly understood extrahepatic disorders.

Natural history of hepatitis B and outcomes after liver transplantation

HBV infection is the single most common cause of cirrhosis globally although the prevalence rate is influenced by geographic region. The natural course of HBV infection and the clinical outcome is dependent on the interplay between host, virus, and environmental factors. Understanding the natural history of HBV infection is important in determining treatment strategies. OLT is the ultimate cure for patients with HBV-related liver failure or HCC. The use of HBIG and new antiviral agents has resulted in significant decrease in HBV re-infection rate and survival of patients transplanted for hepatitis B in recent years is comparable to that of patients transplanted for other liver disease.

Levels of HBV-DNA and HBsAg after acute liver allograft rejection treatment by corticoids and OKT3

The aim of this work was to analyze whether the treatment of acute rejection of orthotopic liver transplants (OLT), either with corticoids or OKT3, has any effect on the levels of hepatitis B virus (HBV)-DNA and HBsAg in individuals which were originally affected by cirrhosis or fulminant hepatic failure as a result of B virus. We have found that HBV-DNA is present in macrophages, B cells and both CD4+ and CD8+ T cells after OLT in all cases studied. Interestingly, the levels of HBV-DNA and HBsAg in the serum analyzed were increased extremely rapidly in the patients treated with OKT3 in an acute rejection episode. However, the serum levels of HBV-DNA and HBsAg found were lower when the patients were treated with steroids, and were not found in non-treated patients. As the serum levels of HBV-DNA increase, the process of liver reinfection could be accelerated; therefore, these results may help to understand how OKT3 and corticoids immunosuppressive therapy may accelerate the reinfection of OLT by HBV. In conclusion, our results suggest that special care must be taken in the use of OKT3 in the treatment of acute liver rejection episodes in chronic or fulminant HBV transplanted patients.

Hepatitis B virus transgenic mouse model of chronic liver disease

A model for hepatitis B virus-associated chronic liver disease has been made using cloned hepatitis B virus DNA as a transgene in a severe combined immunodeficient host. These mice consistently support virus gene expression and replication. After adoptive transfer of unprimed, syngeneic splenocytes, these mice cleared virus from liver and serum, and developed chronic liver disease. This model will permit identification of the host and virus contributions to chronic liver disease in the absence of tolerance.

HBV viral load within subpopulations of peripheral blood mononuclear cells in HBV infection using limiting dilution PCR

Extrahepatic viral load in peripheral blood mononuclear cells (PBMCs) of patients with hepatitis B virus (HBV) is still under debate. In this study, HBV infection rates and viral titers were examined within all PBMC subpopulations using limiting dilution-PCR (LD-PCR). PBMCs of patients with acute or chronic hepatitis B were separated by magnetic beads in monocytes, B-cells, CD4+ T-cells, CD8+ T-cells, and NK cells. Using two-round nested PCR, HBV-DNA sequences were detected in all patients examined within each PBMC subpopulation. The frequencies of HBV-positive cells and viral loads were calculated by Poisson analysis of HBV PCR results from serial dilutions of cells and cell lysates. Highest infection rates were found in monocytes and B-cells followed by CD8 + T-cells, NK cells, and CD4+ T-cells. Concerning all subsets, frequencies of HBV-positive cells were 50- to 500-fold higher in chronic than in acute hepatitis B. Viral loads were mostly estimated at about one HBV genome per HBV-positive cell. Moreover, slightly elevated HBV titers were seen in B-cells, CD4+ T-cells, and NK cells in both acute and chronic hepatitis B. It was demonstrated that beside a generally more latent HBV infection in PBMCs, elevated HBV titers point to replication or selective viral uptake within particular PBMC subsets. Therefore, the data suggest that HBV-infected PBMCs may participate in persistence of HBV.

Liver transplantation in virus-induced chronic liver disease

The current status of liver transplantation (OLTx) for chronic viral hepatitis is reviewed. The major issues addressed include the rate of recurrence of disease, its severity and natural history, and the potential for therapy. These issues vary markedly for each type of viral hepatitis. The development of new antiviral agents for clinical use may change the current restriction on liver transplantation for hepatitis B virus (HBV)-related liver disease such that it begins to challenge hepatitis C virus (HCV) as the principal indication for OLTx world-wide.

Hepatitis B and C viruses and primary liver cancer

The data presented indicate that viral agents (namely, HBV and HCV) are major environmental aetiological factors for human primary liver cancer. It is important to elucidate the molecular mechanisms further because HCC is one of the few examples of virus-related human cancers. In addition, the available evidence points to the possibility of at least partial prevention of the tumour by large-scale vaccination.

Fatal necrotizing pancreatitis caused by hepatitis B virus infection in a liver transplant recipient

A 32-year-old man who had undergone liver transplantation for fulminant hepatitis due to HBV infection developed fatal acute necrotizing pancreatitis on the 60th post-transplant day, while showing signs of intense viral replication. Immunohistochemistry and in situ hybridization of the pancreas following autopsy showed the presence of HBsAG and HBV-DNA in the cytoplasm of acinar cells, together with the picture of necrotizing pancreatitis. Clinical and histological features seem to indicate that pancreatitis was directly caused by HBV infection.

Distribution of hepatitis B virus DNA sequences in different peripheral blood mononuclear cell subsets in HBs antigen-positive and negative patients

Hepatitis B virus (HBV) DNA sequences have been detected in leucocytes from HBV-infected individuals. The aim of this study was to assess the specificity of HBV for a special leucocyte subset in nine healthy chronic HBV carriers, nine HBs antigen-positive patients with chronic active hepatitis, 16 HBs antigen-negative haemophiliacs with HBc and/or HBs antibodies, and 10 patients with HBV-related systemic necrotizing vasculitis. HBV-DNA sequences were found by Southern blot hybridization in the leucocytes of 15 out of the 44 (34%) patients. The prevalence was not significantly different between the four groups. HBV-DNA was found in the CD4+ cells (9/11) as well as in the CD8+ cells (4/11), B cells (4/12) and monocytes (2/12). In conclusion, leucocytes, and particularly CD4+ lymphocytes, are frequently infected by HBV in patients with HBV serum markers.

Alterations in intrahepatic expression of duck hepatitis B viral markers with ganciclovir chemotherapy

Ducks congenitally infected with duck hepatitis B virus (DHBV) were treated with the guanosine analogue, ganciclovir, and the effect on serum and intrahepatic expression of DHBV DNA and viral proteins was examined. After 21 days of ganciclovir treatment, a substantial reduction in viraemia occurred; in contrast, the level of circulating DHBV surface antigen was unchanged. Ganciclovir therapy also substantially reduced the level of DHBV DNA replicative intermediates and the expression of viral core and surface antigen in hepatocytes. However, despite the antiviral treatment some liver cells, including the bile duct epithelial cells and putative oval cells, maintained their intense staining for the viral proteins. Furthermore, DHBV-infected cells in extrahepatic sites such as the pancreas, kidney and spleen were also unaffected by ganciclovir treatment. These results suggest that monotherapy with nucleoside analogues is unlikely to eliminate chronic hepadnaviral infection, and antiviral programs should be designed to target all cell populations infected by the virus.

Hepatitis B virus (HBV) binding factor in human serum: candidate for a soluble form of hepatocyte HBV receptor

A hepatitis B virus (HBV) binding factor (HBV-BF) was identified in normal human serum interacting with the pre-S1 and pre-S2 epitopes of the viral envelope located within the protein domains involved in recognition of hepatocyte receptor(s). This molecule was characterized as a 50-kDa glycoprotein showing an isoelectric point of 7.13 with a biological activity depending on its native molecular conformation and on intact sulfhydryl bonds. Monoclonal antibodies to HBV-BF recognized a membrane component of the normal human liver whereas they were unreactive with hepatocyte membranes of other species and with those of the HepG2 cell line. These results suggest that the HBV-BF represents a soluble fragment of the membrane component and can be related to the HBV receptor mediating attachment of HBV to human liver cells.

Types, causes, and therapies of hepatitis occurring in liver transplant recipients

Liver transplantation (OLTx) has become a common life-saving procedure for individuals with chronic advanced liver disease. It is also used in the clinical treatment of patients with fulminant hepatic failure and those with primary neoplastic disease of the liver. Despite its overall success in restoring meaningful life to those who undergo the procedure, the posttransplant life of a liver allograft recipient is not without hazard. A common problem following liver transplantation is the finding of abnormal liver injury tests reflecting a "hepatitis" that can not be ascribed to allograft rejection. The majority of such cases are a consequence of either a technically flawed operation, drug-induced liver injury, or one or another form of viral hepatitis. Each of these problems is discussed in the following clinical review.

Hepatitis C virus associated primary hepatocellular carcinoma in a noncirrhotic liver

The case of a 71-year-old man with a primary hepatocellular carcinoma in a non-cirrhotic liver is reported. There were no risk factors of hepatocellular carcinoma (HCC)-like liver cirrhosis, alcohol drinking, tobacco smoking, exposure to vinyl chloride, thorotrast, aflatoxin or alpha 1-antitrypsin deficiency. Serologically, the patient was positive for antibodies to the hepatitis B virus (anti-HBc, anti-HBs) and for anti-hepatitis C virus (HCV) antibodies. Virologically, positive and negative strands of HCV RNA could be detected in the patient's serum and tumorous liver tissue by reverse transcription polymerase chain reaction as a sign of persistent HCV replication. Histologically, the HCC was completely surrounded by liver tissue which showed the signs of nodular regenerative hyperplasia. Indeed, the mechanism of hepatocarcinogenesis remains to be clarified. However, this case supports the observation that HCC may also develop in patients with HCV infection without preexisting liver cirrhosis.

Detection of the minus strand of hepatitis C virus RNA by reverse transcription and polymerase chain reaction: implications for hepatitis C virus replication in infected tissue

The combination of reverse transcription and polymerase chain reaction is a very powerful tool for the detection of hepatitis C virus RNA in sera of patients with hepatitis C virus infection. However, when studying the presence of this virus in tissue using polymerase chain reaction, it may be difficult to distinguish between blood viral particles adhering to the tissue and viral RNA contained within the tissue. Because hepatitis C virus has a single-stranded RNA of positive polarity, a minus-strand RNA is expected to be found in hepatitis C virus-replicating tissues as a template for the synthesis of genomic RNA. To see whether the detection of the minus strand of hepatitis C virus RNA by polymerase chain reaction can be used for the determination of hepatitis C virus-replicating tissues, we examined the presence of the minus strand of hepatitis C virus RNA in the plasma, peripheral blood mononuclear cells and liver specimens of patients with hepatitis C virus infection. The plus-strand RNA was detected in the plasma, peripheral blood mononuclear cells and the liver specimens, but the minus-strand RNA was only detected in the liver. These results suggest that hepatitis C virus replicates in the liver but not in peripheral blood mononuclear cells. This detection method for the minus strand of hepatitis C virus RNA should be useful for determining hepatitis C virus replication in tissues other than liver tissue.

Hepatitis B virus. New and evolving issues

Recent developments in molecular biology have advanced our understanding of the pathogenesis of HBV-induced disease. New data derived from the molecular analysis of clinical material have begun to bridge the gap between bench research and the clinical arena. In this review, we consider topics that have relevance to clinical management and that have not been summarized in the recent literature. The recent advances that have been made in the areas of HBV variants, in vitro cell culture systems, and extrahepatic infection are discussed in greater detail.