Acute flares in chronic hepatitis B: the natural and unnatural history of an immunologically mediated liver disease

A treatment algorithm for the management of chronic hepatitis B virus infection in the United States

BACKGROUND AND AIMS

Chronic hepatitis B is an important public health problem worldwide and in the United States. A treatment algorithm for chronic hepatitis B virus (HBV) infection was developed by a panel of US hepatologists based on new developments in the understanding of the virology of HBV, availability of more sensitive molecular diagnostic testing, and advantages and disadvantages of currently approved therapies.

METHODS

This algorithm is based on available evidence, but where data are lacking, the panel relied on clinical experience and consensus expert opinion.

RESULTS

Serum HBV DNA can be detected at levels as low as 100-1000 copies/mL by using molecular assays and should be determined to establish a baseline level before treatment, monitor response to antiviral therapy, and survey for the development of drug resistance. The primary aim of antiviral therapy is durable suppression of serum HBV DNA to the lowest level possible. The threshold level of HBV DNA for determination of candidacy for therapy is >/=10(5) copies/mL for patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B. A lower serum HBV DNA threshold is appropriate for patients with HBeAg-negative chronic hepatitis B and those with decompensated cirrhosis, and the panel recommends thresholds of 10(4) copies/mL and 10(3) copies/mL, respectively.

CONCLUSIONS

Interferon alfa-2b, lamivudine, and adefovir dipivoxil are all approved as initial therapy for chronic hepatitis B and have certain advantages and disadvantages. Issues for consideration include efficacy, safety, incidence of resistance, method of administration, and cost. Studies are under way to explore the safety and efficacy of combination therapy, which may prove to be more effective than monotherapy in suppressing viral replication and may decrease or delay the incidence of drug resistance.

Gemcitabine and reactivation of hepatitis B

Patients with chronic hepatitis B are at risk of reactivation of viral hepatitis during chemotherapy. We report a case of hepatitis B reactivation occurring in association with single-agent gemcitabine chemotherapy in the absence of significant myelosuppression. Gemcitabine is a nucleoside analog that can affect cell-mediated immunity, and this may contribute to an increased risk of reactivation of hepatitis B. We advise caution when administering chemotherapy to patients who are hepatitis B surface antigen positive, even when using relatively nontoxic palliative single-agent cytotoxic drugs. Monitoring of liver function tests will identify hepatitis, and measurement of hepatitis B DNA levels may help distinguish chemotherapy-induced hepatitis from hepatitis B virus reactivation.

Early is superior to deferred preemptive lamivudine therapy for hepatitis B patients undergoing chemotherapy

BACKGROUND & AIMS

Hepatitis B virus reactivation is a serious cause of morbidity and mortality in hepatitis B surface antigen-positive patients treated with chemotherapy. We compared the efficacy of early and deferred preemptive lamivudine therapy in reducing the incidence of hepatitis due to hepatitis B virus reactivation in hepatitis B surface antigen-positive lymphoma patients treated with chemotherapy.

METHODS

Thirty consecutive hepatitis B surface antigen-positive lymphoma patients undergoing intensive chemotherapy were randomized (1:1) to receive lamivudine 100 mg daily 1 week before chemotherapy (group 1) or to have this treatment deferred until there was serological evidence of hepatitis B virus reactivation on the basis of serial 2-week-interval serum hepatitis B virus DNA monitoring by a Digene Hybrid Capture II assay (group 2).

RESULTS

Eight (53%) patients in group 2 and none in group 1 had hepatitis B virus virological reactivation after chemotherapy (P = 0.002). Seven patients in group 2 still had hepatitis (5 anicteric hepatitis, 1 icteric hepatitis, and 1 hepatic failure). Survival free from hepatitis due to hepatitis B virus reactivation in group 1 patients was significantly longer than that in group 2 (P = 0.002 on the log-rank test). The median onset of hepatitis B virus reactivation in these patients was 16 weeks (range, 4-36 weeks) after the initiation of chemotherapy. Three (13%) of the 23 patients treated with lamivudine had hepatitis B virus-related hepatitis after lamivudine withdrawal.

CONCLUSIONS

Lamivudine should be considered preemptively before or at the initiation of chemotherapy for all hepatitis B surface antigen-positive lymphoma patients undergoing intense chemotherapy.

Prevalence and characterization of lamivudine-resistant hepatitis B virus mutations in HIV-HBV co-infected individuals

OBJECTIVE

To determine the prevalence of hepatitis B virus (HBV) genotypic resistance to lamivudine, identify risk factors associated with lamivudine resistance, and characterize the pattern of HBV polymerase mutations in patients co-infected with HIV.

DESIGN

Retrospective cross-sectional study.

METHODS

Thirty-three chronic HBV-infected patients were identified from a cohort of 1719 HIV-infected individuals. Patient information was collected from case records, HBV DNA was measured on stored serum by polymerase chain reaction, and positive samples underwent sequencing of HBV polymerase, basal core promoter and precore regions.

RESULTS

Three groups of patients were identified: group 1 were viraemic in the absence of lamivudine-resistance mutations, group 2 were viraemic in association with lamivudine-resistance mutations, and group 3 were not viraemic. Group 2 patients with lamivudine-resistant mutations had significantly higher HBV-DNA viral loads but did not differ in duration of lamivudine therapy, HBV genotype, HIV viral load or CD4 cell count compared with patients with wild-type HBV. Group 2 individuals also demonstrated significantly higher serum alanine aminotransferase (ALT) levels than group 1, who were higher than group 3. Unique mutations were detected in HBV polymerase, including rtV173L plus rtL180M plus rtM204V, which occurred in three patients. This virus has the in-vitro characteristics of a 'vaccine escape' mutant of HBV.

CONCLUSION

Genotypic HBV lamivudine resistance was found in 39% of HIV-HBV co-infected individuals treated with lamivudine as part of highly active antiretroviral therapy. These patients exhibited significantly elevated HBV viral loads and serum ALT, and three were infected with a lamivudine-resistant HBV strain that was potentially transmissible to HBV-vaccinated individuals.

Steroid-free chemotherapy decreases risk of hepatitis B virus (HBV) reactivation in HBV-carriers with lymphoma

Reactivation of hepatitis is one of the most serious complications of chemotherapy in lymphoma patients who are carriers of the hepatitis B virus (HBV). Glucocorticoids are linked to increased risk of HBV reactivation. This study seeks to clarify whether removal of glucocorticoids from chemotherapy regimens may decrease the risk of HBV reactivation. Eligible patients were seropositive for hepatitis B surface antigen (HBsAg) and had histologically proven non-Hodgkin's lymphomas for which intensive chemotherapy was indicated. Patients were randomized to receive either ACE (epirubicin, cyclophosphamide, and etoposide) or PACE (prednisolone + ACE). A total of 50 patients were enrolled, 25 each for the ACE and PACE arms. The cumulative incidence of HBV reactivation at 9 months after starting chemotherapy was 38% and 73% for ACE and PACE arm, respectively (P =.03). The degree of clinical hepatitis was significantly more severe in the PACE arm: 11 patients (44%) in the PACE and 3 patients (13%) in the ACE arm had ALT elevation more than 10-fold of normal (P =.025), and 7 patients (28%) in the PACE and 1 patient (4%) in the ACE arm had icteric hepatitis (P =.049). Complete remission of tumors occurred in 11 (46%) patients in the PACE and 8 (35%) patients in the ACE arm (P =.556). The estimated overall survival rate at 46 months was 68% in the PACE arm and 36% in the ACE arm, respectively (P =.18). In conclusion, steroid-free chemotherapy decreases the incidence and severity of HBV reactivation in HBsAg-positive lymphoma patients. However, further research is needed to evaluate whether steroid-free chemotherapy may confer a less satisfactory control of lymphoma.

HBcAg-specific CD8 T cells play an important role in virus suppression, and acute flare-up is associated with the expansion of activated memory T cells

We analyzed the prevalence and longitudinal fluctuation of hepatitis B virus (HBV)-specific CD8 T cells in chronic HBV infection using an HLA-A2-HBc18-27 tetramer. Thirty-five HLA-A2-positive patients with chronic HBV infection were divided into 17 HBe antigen (HBeAg)-positive and 18 anti-HBe antibody (anti-HBe)-positive patients. Five HLA-A2-positive normal subjects, five HLA-A2-negative patients with chronic HBV infection, and two HLA-A2-positive patients with acute HBV infection were included as controls. HBc18-27-specific CD8 T cells (c18-27-CD8Ts) were detected at a significantly higher prevalence in patients with anti-HBe (6/18) than in those with HBeAg (1/17), and their frequency reached 0.28% of the total CD8 T cells. The prevalence was significantly higher in patients with HBV DNA below 4.0 log genome equivalents (LGE)/ml (5/12) than in those with HBV DNA above 4.0 LGE/ml (2/23). The frequency of c18-27-CD8Ts was consistently higher in liver-infiltrating lymphocytes, ranging from 0.18 to 1.28%, than in autologous peripheral blood lymphocytes. Longitudinal analysis of patients with acute flare-up demonstrated that the elevation of alanine aminotransferase (ALT) was intimately associated with the expansion of c18-27-CD8Ts. Phenotypic analysis revealed that most c18-27-CD8Ts during acute flare-up expressed HLA-DR and CCR5, while those during low-ALT periods showed low expression. Furthermore, most liver-infiltrating c18-27-CD8Ts were positive for HLA-DR and CCR5, suggesting selective recruitment of activated c18-27-CD8Ts into the liver. In conclusion. HBV-specific CD8 T cells play an important role in the suppression of virus replication, and acute flare-up is associated with the expansion and activation of HBV-specific memory cells.

Hepatitis B virus reactivation after kidney transplantation and new onset lymphoma

A case of hepatitis B virus (HBV) reactivation after kidney transplantation is reported. The presence of antibodies against hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) before transplantation indicated previous infection with HBV. Eight years after transplantation, a diffuse, large B-cell lymphoma occurred, and the patient was positive for HBsAg and hepatitis B e antigen, in association with normal activity of serum aminotransferases. Postmortem liver histology did not show any sign of portal tract or lobular inflammation despite the presence at immunostaining of extensive intranuclear and cytoplasmic positivity for HBcAg, indicating active viral replication. Natural immunity to HBV may not protect against reactivation in patients with a suppressed immune system. In this setting, periodic follow-up of HBV serology in patients at highest risk for HBV reactivation to allow for early diagnosis and prompt treatment with lamivudine is highly recommended.

Hepatitis flares and hepatitis B e antigen seroconversion: implication in anti-hepatitis B virus therapy

Hepatitis flares or acute exacerbations, defined as an abrupt elevation of serum alanine aminotransferase (ALT) over fivefold the upper limit of normal (ULN), of chronic hepatitis B virus (HBV) infection are the results of HLA-I restricted, cytotoxic T lymphocyte (CTL)-mediated immune response against HBV and its downstream mechanisms. Higher ALT levels reflect a more vigorous immune response and a more extensive hepatolysis that, in the extreme situation, may lead to decompensation and failure. In contrast, higher ALT also reflects a more robust immune clearance of HBV and, therefore, a higher chance of HBV-DNA loss and hepatitis B e antigen (HBeAg) seroconversion, both in the setting of natural course and drug therapy. Alanine aminotransferase of fivefold the ULN appears to be a significant cut-off level to categorize the patients in terms of endogenous immune response against HBV. Patients with ALT levels less than fivefold the ULN or those with a less vigorous immune response require immunomodulation to induce robust immune response to enhance HBV clearance. In contrast, those with a more vigorous immune response or those with ALT flare over fivefold the ULN should be monitored closely for spontaneous HBV clearance/HBeAg seroconversion or to start direct antiviral therapy in time to prevent the occurrence or deterioration of hepatic decompensation. In conclusion, a better understanding of the pathogenetic mechanisms and natural course of hepatitis flares, wiser selection of patients and the timing of drug therapy are crucial to achieve better treatment results.

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Clinical and virological aspects of hepatitis B co-infection in individuals infected with human immunodeficiency virus type-1

The improved prognosis of HIV-infection that has occurred since the introduction of highly active antiretroviral therapy (HAART) has resulted in renewed emphasis being placed on co-morbidities associated with HIV-infection, and chronic viral hepatitis in particular. Hepatitis B virus (HBV) infection is an important infection in HIV-1 infected individuals because of the influence of HIV-1 co-infection on the natural history of HBV infection. Antiviral therapies with activity against both viruses have enabled targeted therapy in co-infected individuals, however, optimism regarding improved prognosis has been tempered by the development of antiviral resistant HBV. Emerging new classes of HBV therapies herald the possibility of combination HBV therapy.

A prospective study characterizing full-length hepatitis B virus genomes during acute exacerbation

BACKGROUND & AIMS

Hepatitis B virus (HBV) evolves rapidly in patients with chronic hepatitis B, and HBV variation may trigger acute exacerbation. To study this relationship, we investigated full-length viral sequences before, during, and after exacerbation.

METHODS

We prospectively studied 14 patients with exacerbation of hepatitis B, either spontaneously (n = 4) or after receiving various medical interventions (n = 10), and measured their serum alanine aminotransferase (ALT) and HBV DNA levels monthly. Full-length HBV genomes at baseline, at the peak of serum viral load, at ALT peak, and after ALT peak were obtained by polymerase chain reaction, sequenced, and compared. Replication activities of serial HBV variants were assayed by in vitro transfection.

RESULTS

Serum viral load was increased in all exacerbations. Viral peak preceded ALT peak in 13 (93%) of the 14 patients. At virologic peak, 12 patients (86%) harbored viral genome identical to the corresponding baseline genome. At and after ALT peak, 9 (64%) and 7 (50%) of the viral genomes remained identical to baseline, respectively. Mean nucleotide change per genome was 0.2 at virologic peak but increased to 4.4 and 8.1 at and after ALT peak, respectively. The replication potential of the viral variant that emerged during or after exacerbation was equivalent to that at baseline.

CONCLUSIONS

Most exacerbations were preceded by an upsurge of serum HBV identical to the preexisting HBV strain. After exacerbation, about half of the patients were repopulated by a different viral variant, which was likely a result of immune selection.

Activation of Th1 immunity is a common immune mechanism for the successful treatment of hepatitis B and C: tetramer assay and therapeutic implications

Both chronic hepatitis B and C virus (HBV and HCV) infections respond ineffectively to current antiviral therapies. Recent studies have suggested that treatment outcomes may depend on the development of type 1 T helper (Th1) and Th2 cell responses. Specifically, activation of Th1 immunity may play a major role in successfully treating hepatitis B and C. This model was revisited herein by evaluating immune responses in 36 HBV and 40 HCV patients with or without treatment, in an attempt to find a common immune mechanism for successful treatment. The immune responses in all examined cases were studied by peripheral blood mononuclear cell (PBMC) proliferation and cytokine responses to viral antigens, cytotoxic T lymphocyte (CTL) responses, enzyme-linked immunospot (ELISPOT) assay, and tetramer staining of virus-specific CD8+ T cells. The overall results revealed that all responders among both HBV- and HCV-infected cases displayed significantly higher PBMC proliferation to viral antigens with a predominant Th1 cytokine profile. Furthermore, the Th1-dominant responses were associated with significant enhancement of CTL activities and were correlated with ELISPOT data, while non-responders responded more weakly. During therapy, the numbers of tetramer-staining, virus-specific CD8+ T cells showed greater increases in responders than in non-responders (p = 0.001). The frequencies determined by the tetramer assay were approximately 200-fold higher than data estimated by limiting-dilution analysis. In conclusion, activation of Th1 immunity accompanied by enhancement of CTL activity during therapy is a common immune mechanism for successfully treating hepatitis B and C, and therefore may have important therapeutic implications.

Efficacy of lamivudine therapy for advanced liver disease in patients with precore mutant hepatitis B virus infection awaiting liver transplantation

BACKGROUND

Orthotopic liver transplantation (OLT) for end-stage liver disease resulting from hepatitis B virus (HBV) infection is associated with a high rate of recurrence and reduced survival. Lamivudine is effective in inhibiting HBV replication in patients with chronic hepatitis. This study evaluated the impact of lamivudine on viral suppression, liver function, and disease severity in patients awaiting OLT with HBV e-minus strain infection.

METHODS

Twenty-five patients received lamivudine (100 mg per day) from the day of listing for OLT. All patients were positive for serum HBV-DNA by polymerase chain reaction and all had a Child-Pugh score of 7 or higher.

RESULTS

Patients were followed for 12+/-9 months (mean +/- SD). Eleven underwent OLT within 13 months of treatment initiation, one died after 10 months, and one dropped out after 3 months. After 3, 6, and 9 months, HBV-DNA by polymerase chain reaction was undetectable in 14 of 25, 14 of 20, and 13 of 15 patients, respectively. Two patients developed lamivudine resistance after 9 and 18 months of treatment, respectively, without liver decompensation. Comparing baseline to last visit data, a significant improvement in prothrombin activity (43+/-15% vs. 52+/-19%; P=0.0014), serum bilirubin (3.4+/-1.9 vs. 2.5+/-2.2 mg/dL; P=0.0007), serum albumin (3.3+/-0.3 vs. 3.6+/-0.5 g/dL; P=0.0278), presence of ascites (15/25 vs. 7/25; P=0.0047), and Child-Pugh score (9 vs. 8; P=0.0003) was observed. Because of liver function improvement, four patients were placed on low priority status for OLT (United Network of Organ Sharing 3) and 9 on inactive status (United Network of Organ Sharing 7). The overall probability of survival at 6 and 12 months was 100% and 90.9%, respectively.

CONCLUSIONS

Lamivudine has an important role in patients with end-stage liver disease caused by HBV precore mutant strain. Not only does HBV-DNA suppression allow patients to be eligible for OLT, but the improvement of the patients' clinical status may delay the need for OLT in an era of organ shortage.

Preemptive use of lamivudine reduces hepatitis B exacerbation after allogeneic hematopoietic cell transplantation

Exacerbation of hepatitis B virus (HBV) is a serious cause of morbidity and mortality in hepatitis B surface antigen (HBsAg)-positive patients undergoing transplantation. Our aim was to evaluate the effectiveness of lamivudine to prevent hepatitis due to exacerbation of HBV in HBsAg-positive patients treated with allogeneic hematopoietic cell transplantation. We studied 20 consecutive HBsAg-positive recipients of allogeneic hematopoietic cell transplantation who received lamivudine 100 mg daily starting one week before transplantation until week 52 after transplantation (group 1). Serial serum alanine aminotransferase and HBV DNA levels were measured before and after transplantation at 4- to 8-week intervals for the first year and then 4- to 12-week intervals. Their virologic and clinical outcomes were compared with 20 case-matched recipients who did not receive any antiviral therapy to HBV (anti-HBV) before and after hematopoietic cell transplantation (group 2). After transplantation, 9 patients (45%) in group 2 and one patient (5%) in group 1 had hepatitis due to exacerbation of HBV (P <.008), with 3 hepatic failures in group 2 and none in group 1. The one-year actuarial probability of survival without hepatitis due to exacerbation of HBV was higher in group 1 than group 2 (94.1% vs. 54.3%, P =.002). By multivariate Cox analysis, preemptive use of lamivudine effectively reduced hepatitis due to exacerbation of HBV (adjusted hazards ratio, 0.09; P =.021). In conclusion, preemptive lamivudine reduced HBV exacerbation. The use of lamivudine with other immunosuppressive regimens to prevent exacerbation of HBV should be further explored.

Global control of hepatitis B virus infection

Worldwide about 350 million people are chronic carriers of the hepatitis B virus (HBV). The infection can cause acute and chronic liver disease including cirrhosis and hepatocellular carcinoma (HCC). Hepatocellular injuries of HBV infection are predominantly immune-mediated, and the natural history of chronic infection can be divided into three phases based on virus-host interactions-namely, immune tolerance, immune clearance, and viral integration phases. Four serotypes (adw, ayw, adr, and ayr) and seven genotypes (A to G) of HBV have been identified, and they show some distinct geographic distributions. The HBV genotypes may have clinical relevance and are currently under investigation. On the basis of disease burden and the availability of safe and effective vaccines, the WHO recommended that by the end of the 20th century hepatitis B vaccine be incorporated into routine infant and childhood immunisation programmes for all countries. The efficacy of universal immunisation has been shown in different countries, with striking reductions of the prevalence of HBV carriage in children. Most important, hepatitis B vaccination can protect children against HCC and fulminant hepatitis, as has been shown in Taiwan. Nevertheless, the implementation of worldwide vaccination against HBV requires greater effort to overcome the social and economic hurdles. Safe and effective antiviral treatments are available but are still far from ideal, a situation that, hopefully, will be improved soon. With hepatitis B immunisation, the global control of HBV infection is possible by the end of the first half of 21st century.

Hepatitis B viral genotypes: clinical relevance and molecular characteristics

Hepatitis B virus (HBV) infection is a global health problem and the clinical outcome of chronic HBV infection depends on the frequency and severity of hepatitis flares in the immune clearance phase. Currently, four subtypes and seven genotypes of HBV are identified and most have specific geographic distributions. The impact of HBV genotypes on the clinical outcome of chronic HBV infection has been partially clarified. In Taiwan, genotype C is associated with more severe liver disease and genotype B is associated with the development of hepatocellular carcinoma (HCC) in young non-cirrhotic patients. In contrast, genotype B has a relatively good prognosis in Japan and China and is rarely associated with the development of HCC. Similarly, genotype D is associated with more severe liver disease than genotype A in India and may predict occurrence of HCC in young patients. Although superinfection of HBV on top of hepatitis B carriers occurs in Taiwan, it is rarely associated with acute exacerbations. As to the response to antiviral treatment, genotypes C and D are associated with a lower response rate to interferon therapy compared with genotypes B and A. In addition, the subtype adw is reported to be associated with a higher risk of lamivudine resistance than ayw. In HBV subtype adw-infected HCC patients, genotype B responds better to embolization therapy and has a lower rate of HCC recurrence than genotype C. In summary, pathogenic and therapeutic differences do exist among HBV genotypes and determining the genotype in patients with chronic HBV infection would help gain further information for etiologic, clinical, virologic and anthropologic investigations. Further studies to clarify the molecular virological factors that contribute to these differences are awaited.

Prevalence and interaction of hepatitis B and latent tuberculosis in Vietnamese immigrants to the United States

OBJECTIVES

Southeast Asian immigrants, with a high prevalence of both hepatitis B and latent tuberculosis, constitute a large proportion of immigrants to the United States. Isoniazid hepatotoxicity may be associated with hepatitis B. This study was conducted to document the prevalence and interaction of hepatitis B, latent tuberculosis, and isoniazid toxicity.

METHODS

Hepatitis B surface antigen (HBsAg) and tuberculin skin testing was done on 743 Vietnamese immigrants to the Midwest between January, 1991 and December, 1999. HBsAg positive cases were tested for hepatitis B e antigen (HBeAg). All tuberculin skin test-positive patients were treated with isoniazid, unless contraindicated. Complications of isoniazid treatment and compliance with hepatitis B virus immunization recommendations were evaluated.

RESULTS

One hundred three subjects (13.86%) had HBsAg, and 43 (5.7%) HBeAg. Prevalences of latent tuberculosis were similar in HBsAg positive (53%) and HBsAg negative (45%) subjects. Sixty-two percent of HBeAg positive versus 19% of HBeAg negative subjects had hepatotoxic side effects requiring discontinuation of treatment (relative risk [RR] = 11.38, CI = 5.49 < RR < 23.59, p < 0.001). Three cases of severe isoniazid hepatitis occurred in 21 HBeAg positive subjects, versus no cases in 121 HBeAg negative cases treated with isoniazid (RR = 7.72, CI = 5.02 < RR < 11.88, p < 0.001). Only 58% of subjects at risk of developing hepatitis B virus infection were appropriately immunized.

CONCLUSIONS

Vietnamese immigrants have a high prevalence of hepatitis B and latent tuberculosis. HBeAg positive cases have a 7.7-fold increased risk of serious isoniazid toxicity and an 11.3-fold increased risk of isoniazid side effects requiring discontinuation of treatment. HBeAg represents an important risk factor for severe isoniazid hepatitis.

Genotypes and clinical phenotypes of hepatitis B virus in patients with chronic hepatitis B virus infection

Genotype C of hepatitis B virus (HBV) has been shown to be associated with a poor clinical outcome, compared to genotype B. To explore the clinical phenotypes, with special reference to the seroconversion of hepatitis B e antigen (HBeAg) and frequency of acute exacerbation between patients infected with HBV genotypes B and C, a cohort of 272 Taiwanese patients with chronic HBV infection was analyzed. According to the status of HBeAg at enrollment and frequency of acute exacerbation during the follow-up period, five groups of patients with distinct clinical phenotypes were categorized. Of the 272 HBV carriers, 185 (68%) were infected with HBV genotype B and the remaining 87 (32%) were infected with genotype C. Among them, 150 (55%) were positive for HBeAg and patients with genotype C infection tended to have a higher positive rate of HBeAg than those with genotype B infection (63 versus 51%). Genotype B was more prevalent than genotype C in different groups of HBV carriers. However, the prevalence of genotype C in patients with multiple episodes of acute exacerbation who failed to have HBeAg seroconversion was significantly higher than in all 272 patients (50 versus 32%, P = 0.025), in those with HBeAg seroconversion after only one episode of acute exacerbation (50 versus 12%, P = 0.01), or in those negative for HBeAg at enrollment and without acute exacerbations (50 versus 23%, P = 0.002). In conclusion, patients with genotype C infection have a more aggressive clinical phenotype than do those with genotype B infection, which contributes to the former group's progressive liver disease and poor clinical outcomes.

Serum hepatitis B virus DNA levels and liver histology in inactive HBsAg carriers

BACKGROUND/AIMS

A recent NIH research workshop on hepatitis B virus (HBV) revisited the definition of healthy HBsAg carriers. The new definition inactive surface antigen (HBsAg) carriers includes an estimated serum HBV DNA level below 105 copies/ml. However, this cut-off value needs to be confirmed.

METHODS

Eighty-five consecutive patients, HBsAg-positive/HBeAg-negative with persistently normal alanine aminotransferase (ALT) and undetectable serum HBV DNA with standard assay (Versant HBV DNA Assay (bDNA), Bayer) were prospectively followed for 3.2+/-2.6 (range 0.5-11) years; 58 underwent a liver biopsy. Serum HBV DNA was quantified with a sensitive polymerase chain reaction assay (Cobas Amplicor HBV Monitor, Roche) (sensitivity 200 copies/ml), and liver histology was assessed using the Ishak scoring system.

RESULTS

The median serum HBV DNA level was 1300 copies/ml (<200-179 x 10(3) copies/ml), 16% of the subjects had no detectable serum HBV DNA and 98% had levels below 10(5) copies/ml. Histologic lesions were mild (total score <7) in all cases. Loss of HBsAg was observed in three patients, three patients experienced a transient increase in ALT (<2 x upper limit of normal), and serum HBV DNA levels remained stable (1-6 years) in 97% of the 38 patients retested.

CONCLUSIONS

In our study of inactive HBsAg carriers, the median serum HBV DNA level was 1300 copies/ml, the serum HBV DNA level was below 10(5) copies/ml in 98% of the patients, and remained stable; histological lesions were mild in all cases.

How will we use the new antiviral agents for hepatitis B?

There are two licensed drugs for chronic hepatitis B virus (HBV), interferon alfa and lamivudine, with similar efficacy rates. Lamivudine is less expensive and better tolerated than interferon alfa and is the drug of choice for patients with decompensated cirrhosis and recurrent HBV infection after liver transplantation. The major problem with lamivudine monotherapy has been the emergence of drug-resistant HBV polymerase (YMDD) mutants. Thus, long-term use of lamivudine in other settings remains somewhat controversial. Alternative nucleoside analogues that are active against both wild-type and YMDD-mutant HBV are currently being tested. It is hoped that a combination of one or more of these agents with lamivudine will not only prove more effective than lamivudine alone but also decrease the rate of lamivudine resistance. Preliminary studies suggest that the combination of interferon and lamivudine is associated with an enhanced rate of virologic response when compared with either agent alone. From a theoretical perspective, the combination of interferon with one or more nucleoside analogues may be the most effective way to treat HBV infection in many clinical situations.

Hepatoimmunology: a perspective

Premises for the subspecialty of hepatoimmunology include the recognition that the liver is a lymphoid organ with unique immunological properties. These properties ensure efficient innate defence against intestinal microbes and toxins, confer a particular capacity for induction of tolerance, and provide for apoptotic disposal of redundant lymphocytes. Pathological responses within the liver are elicited when: (i) hepatotropic viruses (hepatitis virus B and C) escape immune elimination and reside in hepatocytes; (ii) the liver becomes the site of autoimmune responses directed against either hepatocytes (autoimmune hepatitis) or biliary ductules (primary biliary cirrhosis); or (iii) the liver in the course of disposal of drugs generates neoantigens that provoke adverse allergic responses. Recent advances in the understanding of the immunopathogenesis of these entities are reviewed.