Hepatitis B: global importance and need for control

Natural history of patients with recurrent chronic hepatitis C virus and occult hepatitis B co-infection after liver transplantation

It is uncertain whether occult hepatitis B virus co-infection will hasten progressive liver disease in chronic hepatitis C patients after liver transplantation. This study evaluated fibrosis progression and severe fibrosis in 118 consecutive hepatitis B surface antigen-negative patients with virological and histological evidence of recurrent chronic hepatitis C infection co-infected with occult hepatitis B virus after liver transplantation. HBV DNA was detected from serum at the time of recurrent chronic hepatitis C infection by polymerase chain reaction. Each subject underwent a repeat liver biopsy 5 years post-liver transplantation. Occult hepatitis B virus co-infection was present in 41 of the 118 (34.7%) patients. At 5 years post-liver transplantation, 13 of the 41 occult hepatitis B virus co-infected patients compared with 16 of the 77 patients without occult hepatitis B virus co-infection developed fibrosis progression (31.7% vs. 20.8%, respectively, p = 0.39). Eight of 41 the occult hepatitis B virus co-infected patients compared with 13 of the 77 patients without occult hepatitis B virus co-infection had severe fibrosis (19.5% vs. 16.9%, respectively, p = 0.97). In conclusion, occult hepatitis B virus co-infection in patients with recurrent chronic hepatitis C infection was not associated with accelerated fibrosis progression or severe fibrosis after liver transplantation.

Early detection and quantification of lamivudine-resistant hepatitis B virus mutants by fluorescent biprobe hybridization assay in lamivudine-treated patients

BACKGROUND

Long-term lamivudine treatment induces the emergence of lamivudine-resistant hepatitis B virus (HBV). The objective of this study was to develop a fluorescent biprobe hybridization (FBH) assay for the detection and quantification of HBV mutants in the clinical course of lamivudine-treated patients and to evaluate its clinical usefulness.

METHODS

We developed an FBH assay to detect mutations in the HBV DNA polymerase gene. The assay's detection sensitivity was determined using a dilution series of wild-type/mutant plasmid DNA. Blood samples obtained from 27 lamivudine-treated patients were analyzed.

RESULTS

Mutant DNA levels as low as 10% of total HBV DNA were detected (sensitivity = 100%, specificity = 80%). HBV mutants were detected in five of the 27 patients during an average follow-up of 20 months after lamivudine administration. In one of the five patients, the YIDD mutant was detected at the initiation of lamivudine treatment, while the remaining four patients were identified as having YIDD mutants within 3 months after beginning lamivudine administration. Of the five patients with an HBV mutant, four developed breakthrough hepatitis more than 10 months after the detection of HBV mutants, following the reappearance or a re-increase of HBV DNA, characterized by a predominance of the mutant. The YIDD mutant was detected in one patient, even when the titer of the serum HBV DNA was below the detection limit of commercially available quantitative polymerase chain reaction.

CONCLUSIONS

The FBH assay is an efficient method for detecting and quantifying HBV mutants, as early as 3 months after lamivudine administration.

Chronic hepatitis B: current testing strategies

The worldwide burden of hepatitis B mandates accurate and timely diagnosis of patients infected with the hepatitis B virus (HBV) and the use of treatment strategies derived from evidence-based guidelines. HBV is a DNA virus that produces a series of viral protein products circulating HBV DNA. Serologic and nucleic acid testing are critical to disease prevention and treatment objectives. Information from such testing helps determine patients' infectivity and immune status, appropriate monitoring strategies, and the efficacy of treatment, as well as providing data that contributes to a better understanding of the natural history and epidemiology of the disease. This article reviews the clinical use of state-of-the-art serologic and nucleic acid tests, including the relevance of hepatitis B e antigen and antibody and HBV DNA measurements as markers of disease activity. Viral load can be used to distinguish between active and inactive disease, define response to therapy, and detect the development of antiviral resistance. Some recent reports have suggested that high viral load is associated with poorer patient outcomes (eg, more rapid progression to cirrhosis and a higher incidence of hepatocellular carcinoma). Durable suppression of HBV DNA is evolving to become the primary goal of therapy, although all currently licensed medications have used histology as the primary end point of therapy. Suggested frequencies for HBV DNA monitoring are presented.

Reactivation of hepatitis and lamivudine therapy in 11 HBsAg-positive renal allograft recipients: a single centre experience

BACKGROUND

In hepatitis B virus (HBV) surface antigen (HBsAg) (+) renal allograft recipients, the mortality associated with liver disease reaches 37-78%. An antiviral agent, lamivudine, has recently been reported to be safe and effective for preventing hepatic damage in these patients, although either resurgence of HBV-DNA levels after discontinuation or emerging resistant HBV mutants caused by long-term administration are still unsettled.

METHODS

Between July 1976 and December 2003, 555 renal transplantations were performed in our centre. Of these, 11 patients who were HBsAg (+) at the time of transplantation (2.0%) were selected for this study. We investigated the incidence of hepatitis reactivation for three yr after transplantation and their clinical courses, including the efficacy of lamivudine therapy in seven of the 11 patients.

RESULTS

Six episodes of hepatitis reactivation developed in five of the 11 patients (45.5%) within three yr after transplantation. Five episodes of six occurred within four months after transplantation. The patient who underwent the most severe reactivation needed intensive care including lamivudine administration and plasma exchange. Lamivudine caused no severe adverse effects and HBV-DNA levels dropped to under measurable levels within four months after lamivudine administration in all patients. Resistant HBV mutant emerged in only one patient, who had the longest lamivudine administration of 49 months.

CONCLUSIONS

For HBsAg (+) renal allograft recipients, careful monitoring of HBV-DNA levels and timely administration of lamivudine could prevent hepatic damage caused by reactivation of hepatitis.

Changing patterns of hepatitis B infection in Italy and NAT testing for improving the safety of blood supply

In Italy, as in most industrialized countries, the burden of hepatitis B has progressively declined in recent decades as a consequence of general improvements in hygiene and standard of living, the introduction of several public health measures, refinement in blood screening and the implementation of specific vaccination programmes. Universal hepatitis B vaccination for all infants and adolescents as well as individuals at increased risk has resulted in considerable progress towards prevention and control of HBV infection. The residual risk of transmitting blood-borne viruses through transfusion is currently very low. Nucleic acid testing can shorten the window period and, consequently, further reduce the risk of viral transmission. Blood donor screening for HCV by NAT was initiated in Italy in 2001 and became mandatory in June 2002. NAT for HIV is currently mandatory in four regions, not mandatory but almost universally performed in another thirteen regions, and not yet introduced in the remaining four regions. NAT for HBV is currently mandatory in four regions and under evaluation in the remaining. NAT for HBV may be a useful tool in detecting acute viral infections in the window phase as well as the occult infections. Its efficacy in improving the safety of blood supply is expected to be higher in countries with intermediate/high endemicity, where anti-HBc antibody screening cannot be routinely performed. There is agreement that, at present, the implementation of HBV DNA testing will not allow for discontinuation of screening for HBsAg.

Genotype, phylogenetic analysis, and transmission pattern of occult hepatitis B virus (HBV) infection in families of asymptomatic HBsAg carriers

Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in the serum in absence of hepatitis B surface antigen (HBsAg). Studies were conducted to screen for occult HBV infection among family members of HBV carriers, incidentally detected positive for HBV infection with a view to assess the pattern of virus transmission among them. Nested PCR assay, employing independent sets of primers to surface and core genes, was used for detection of HBV DNA in serum samples from 28 index cases with asymptomatic HBV infection, and in serum samples from 72 HBsAg negative/anti-HBc positive family members. HBV DNA was detected in 15 HBsAg negative family members of 10 HBsAg positive index patients and was studied in detail. Direct sequencing of S gene region of 25 isolates (10 index cases and 15 contacts) and phylogenetic analysis with data base sequences revealed that genotypes A, C, and D and subtype adw2, adr, and ayw3 were present among them. Evidence of transmission from outside family sources was found in addition to intrafamilial transmission among individuals with occult infection. Mutations in the major hydrophilic loop (MHL) of the S gene region were also detected, including the 'vaccine escape' mutation G145R in three cases. Although majority of the occult infection was associated with low viral load, 3/15 (20%) cases were with higher viral load and potential infectivity. These cases are especially notable in diagnostic, blood banking, and transplantation services.

[Coinfection between hepatitis B virus and malaria: clinical, serologic and immunologic aspects]

The Amazon region is known for a high prevalence of hepatitis B infection, and accounts for more than 90% of malaria cases in Brazil. It has been suggested that the occurrence of coinfections may be important, and may influence the natural history of both diseases. This study evaluated 545 patients with acute malaria, in Coari, Western Brazilian Amazon. 333 (61.1%) presented Plasmodium vivax malaria, 193 (35.4%) Plasmodium falciparum and 19 (3.5%) mixed infections. The HBsAg prevalence was 4.2% and total anti-HBc 49.7%. Patients with HBV serological markers presented no clinical differences than those with malaria only, nor showed any association with classic signs of hepatic disorder. Although showing no statistical significance, HBsAg reactive subjects presented lower parasitic load and higher antibody titers, suggesting the possibility that the immune response in a coinfected individual is differentiated and leads to a variation in the parasite load and antibody production.

Rapid and accurate genotyping of YMDD motif variants in the hepatitis B virus genome by an improved reverse dot blot method

By using the "flow-through hybridization" principle, we developed a new, rapid and accurate reverse dot blot (RDB) method to detect lamivudine resistance-associated YMDD motif variants in hepatitis B virus (HBV) genome. The improved RDB method was very fast at simultaneously detecting HBV YMDD wild-type and mutant motifs. In a blind analysis, 100 samples previously genotyped by DNA clonal sequencing analysis were used to evaluate the sensitivity and specificity of this assay. Conventional restriction fragment length polymorphism (RFLP) data were also used to test our method. In blind experiments, our improved RDB method had an accuracy and specificity of 100%, which was much higher than RFLP, which had an accuracy and specificity of only 83.0%. In clinical detection practice, 49 patients highly suspected of lamivudine resistance were successfully diagnosed by this method. Our improved RDB assay is a simple, rapid, cheap, semiautomatic, accurate, sensitive, and contamination-proof method of detecting lamivudine resistance-associated mutants in the human hepatitis B virus genome.

Current treatment and future directions in the management of chronic hepatitis B viral infection

The World Health Organization places hepatitis B virus (HBV) in the top 10 causes of death worldwide. It is estimated that there are over 400 million carriers of HBV as well. At least 20% to 30% of hepatitis B surface antigen (HBsAg) carriers will die of complications of chronic liver disease, including cirrhosis and liver cancer. The serious consequences of end-stage liver disease and liver cancer occur in 30% of chronic carriers and confront patients and physicians throughout the world. Vaccination is the major form of treatment (prevention) that may eventually eliminate HBV worldwide. This article discusses the currently available treatments as well as evolving treatments for chronic HBV infection.

Vaccines for preventing hepatitis B in health-care workers

BACKGROUND

Hepatitis B virus (HBV) causes acute and chronic liver diseases. Hepatitis B vaccination is recommended for health-care workers.

OBJECTIVES

To assess the beneficial and harmful effects of hepatitis B vaccination in health-care workers.

SEARCH STRATEGY

We searched the trial registers of The Cochrane Hepato-Biliary Group, The Cochrane Library, MEDLINE, and EMBASE to February 2003.

SELECTION CRITERIA

Randomised trials comparing any dose, injection route, injection site, or schedule of hepatitis B plasma-derived vaccines (PDV) or recombinant vaccines (RV) versus placebo, no intervention, or another hepatitis B vaccine in health-care workers.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted the data independently. The reviewers assessed the methodological quality of the trials regarding generation of the allocation sequence, allocation concealment, double blinding, and follow-up. The results were presented as relative risk (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We identified 21 randomised trials, all with one or more methodological weaknesses. Four trials demonstrated that PDV versus placebo significantly decreased hepatitis B events at maximum follow-up (RR 0.51, 95% CI 0.35 to 0.73). RV did not differ significantly from PDV in eliciting a protective hepatitis B surface antibody (anti-HBs) level in two trials. Both vaccines were well tolerated. Low-dose vaccine (1 or 2 microg) by the intradermal route resulted in significantly more participants without protective anti-HBs level compared with high-dose (10 or 20 microg) by the intramuscular route (RR 1.41, 95% CI 1.13 to 1.76). The intradermal route caused significantly more local adverse events, while the intramuscular route caused significantly more systemic adverse events. The gluteal injection produced significantly more participants without protective anti-HBs level than the deltoid injection. The prevalence of anti-HBs seroconversion by rapid vaccination (0, 1, and 2 months) was significantly lower than that by standard vaccination (0, 1, and 6 months). Booster vaccinations with different RV doses (2.5, 5, 10, 20, or 40 microg) produced similar prevalence of anti-HBs seroconversion in three trials assessing participants who did not respond to previous HBV vaccination.

AUTHORS' CONCLUSIONS

PDV significantly prevents hepatitis B events. RV seems to be able to elicit similar protective anti-HBs levels. The intramuscular route with 20 microg RV was significantly more effective compared with the intradermal route with 2 microg RV as was the standard schedule compared with a rapid schedule and deltoid intramuscular injection compared with the gluteal intramuscular injection. It is unclear if booster vaccination of non-responders offers higher anti-HBs seroconversion and hepatitis B vaccine prevents the infection of hepatitis B mutants in health-care workers.

High rates of early HBeAg seroconversion and relapse in Indian patients of chronic hepatitis B treated with Lamivudine: results of an open labeled trial

Background

The use of Lamivudine in chronic hepatitis B (CHB) is well known, however the reported rate of HBeAg sero-conversion and its durability post-treatment have varied considerably. We undertook the present study to study the effect of Lamivudine on HBeAg loss and seroconversion rates in Indian patients of CHB in relation to frequency, predictors and durability.

Methods

We treated 60 patients of e antigen positive CHB (with active viral replication and ongoing necro-inflammatory activity) with Lamivudine. They were followed up by monthly aminotransferases, and 3 monthly HBeAg and anti-HBe. Those who attained HBeAg sero-conversion were advised to discontinue Lamivudine after 6 months and followed up every 3 months thereafter, to see for relapse. Treatment was given for maximum of 3 years if not sero-converted.

Results

The annual incremental loss of HBeAg in patients receiving Lamivudine was 25 (41.6%) at end of 1^st year, 33 (55%) at 2^nd year and 35 (58.3%) at 3^rd year. The corresponding rates for full sero-conversion were 17/60 (28.6%), 22/60 (36.6%) and 24/60 (40%) in the 3 years. HBeAg loss correlated with increased pre-therapy ALT levels (p = 0.002) and decreased pretreatment HBV-DNA levels (p = 0.004). The presence of cirrhosis had no influence on the rate of HBeAg loss. Relapse occurred in 35% (7/20) post-treatment at median time of 6 months.

Conclusion

Indian patients showed a higher rate of HBeAg sero-conversion in the first year of Lamivudine treatment. This correlated with baseline ALT and inversely with HBV-DNA levels. Relapse rate after treatment was high and occurred soon after stopping treatment.

Genotyping of hepatitis B virus isolated from chronic hepatitis B patients in the south of Turkey by DNA cycle-sequencing method

The 8 genotypes of hepatitis B virus (HBV A-H) show a distinct geographic distribution and influence the course of disease and the prognosis of treatment. In this study, we have genotyped 50 HBV isolates circulating in the south of Turkey by DNA cycle sequencing, based on their compatibility with reference sequences of a part of S gene. In our cases, all 50 (100%) HBV sequences from the patients demonstrated full compatibility with the sequences of ayw subtype viruses in genotype D. However, we have found some nucleotide sequence variations within genotype D, 47 (94%) of which were related to HBVGEN1 (Z35716 genotype D) and 3 (6%) were related to HBVDNA (X68292, genotype D).

Hepatocytes targeting of cationic liposomes modified with soybean sterylglucoside and polyethylene glycol

AIM

In this study, a hepatocyte-specific targeting technology was developed by modifying cationic liposomes with soybean sterylglucoside (SG) and polyethylene glycol (PEG) (C/SG/PEG-liposomes).

METHODS

The liposomal transfection efficiencies in HepG(2) 2.2.15 cells were estimated with the use of fluorescein sodium (FS) as a model drug, by flow cytometry. The antisense activity of C/SG/PEG-liposomes entrapped antisense oligonucleotides (ODN) was determined as HBsAg and HBeAg in HepG(2) 2.2.15 cells by ELISA. The liposome uptake by liver and liver cells in mice was carried out after intravenous injection of (3)H-labeled liposomes.

RESULTS

C/SG-liposomes entrapped FS were effectively transfected into HepG(2) 2.2.15 cells in vitro. C/SG/PEG-liposomes entrapped ODN, reduced the secretion of both HBsAg and HBeAg in HepG(2) 2.2.15 cells when compared to free ODN. After in vivo injection of (3)H-labeled C/SG/PEG-liposomes, higher radiation accumulation was observed in the hepatocytes than non-parenchymal cells of the liver.

CONCLUSION

C/SG/PEG-liposomes mediated gene transfer to the liver is an effective gene-delivery method for hepatocytes-specific targeting, which appears to have a potential for gene therapy of HBV infections.

N/A

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[Hepatitis B and D virus infection within Amerindians ethnic groups in the Brazilian Amazon: epidemiological aspects]

Several studies describe very high prevalence rates of infection and disease of hepatitis B and D within Native American population. This is a review of what has been described among Amerindians of Brazilian Amazon. Some groups show low prevalence rates of HBsAg, whereas, others of the same region reveal high endemic pattern, even among individuals less then 10 years of age. HDV is only found in groups of Amazonas province. Transmission may occur by interfamilial dissemination or sexual contact among young adults. Socio-cultural, genetic, and ecological factors are described as determinants of this unique pattern. Nevertheless, the origin of these two viruses is yet to be disclosed. Amerindians population and their genetic memory are a live experiment, which demands a broad investigation, weighting with modern tools, as molecular biology, the influence of historical, genetic, medical and anthropological factors.

Effects of indomethacin on viral replication markers in asymptomatic carriers of hepatitis B: a randomized, placebo-controlled trial

OBJECTIVES

Previous studies have suggested some benefits of nonsteroidal antiinflammatory drugs (NSAIDs) use in patients with chronic viral hepatitis. We evaluated potential effects of indomethacin in asymptomatic carriers of hepatitis B surface antigen (HBsAg).

DESIGN

Randomized, placebo-controlled, double-masked clinical trial.

METHODS

One hundred and twelve patients who were confirmed to be HBsAg carriers for at least 6 months and had normal liver function tests, normal abdominal sonography, and no sign of cirrhosis were randomly assigned into two groups. One group (56 participants, mean age (+/-SD) 31.7 (+/-9.6) yr, 29 male, mean serum alanine aminotransferase (ALT) (+/-SD) 24.9 (+/-9.2)) received indomethacin capsules (25 mg) three times daily and the other group (56 participants, mean age (+/-SD) 33.8 (+/-10.2) yr, 33 male, mean serum ALT (+/-SD) 24.5 (+/-8.7)) took placebo capsules with identical package and appearance. All participants were under treatment for 6 months and were followed 3 months thereafter. Statistical analyses were performed both by intention-to-treat and on-treatment methods.

RESULTS

Nine participants in the indomethacin group (16%) and 8 in the placebo group (14%) did not complete the trial. HBsAg seroconversion did not differ by treatment group (2 subjects in each group became seronegative). Hepatitis B virus DNA (HBV-DNA) became negative in sera of 7 participants in the indomethacin group but only in 1 in the placebo group (intention-to-treat p= 0.06; on-treatment p= 0.03). Seroconversion of HBeAg to anti-HBe occurred only in 5 participants in the indomethacin group (intention-to-treat p= 0.06; on-treatment p= 0.03). Adverse events included one case of hepatotoxicity and two cases of gastritis in the indomethacin group and one suspected gastritis in the placebo group.

CONCLUSIONS

We suggest use of indomethacin only in the subgroup of asymptomatic HBsAg carriers who have detectable HBV-DNA or HBeAg in their sera.

A long-term follow-up study on hepatitis B surface antigen-positive patients undergoing allogeneic hematopoietic stem cell transplantation

The long-term hepatic complications after allogeneic hematopoietic stem cell transplantation (HSCT) in hepatitis B virus (HBV) endemic area are unknown. We examined the serological and liver-related outcome of 803 consecutive patients who received allogeneic HSCTs, with a median follow-up period of 83 months (range, 0.5-155 months). Late HBV-related hepatitis occurred in 2 of the 721 hepatitis B surface antigen-negative (HBsAg-) recipients compared with 16 of the 82 HBsAg+ recipients after HSCT (0.3% vs 19.5%; P < .001 by log-rank). Liver cirrhosis developed in 8 of the 82 HBsAg+ recipients compared with none of the 721 HBsAg- recipients (9.8% vs 0%; P < .001 by log-rank). Twenty of the 31 (64.5%) HBsAg+ recipients of hematopoietic stem cells from donors with natural immunity to HBV had sustained serologic clearance of HBsAg after HSCT. Eight of the 62 recipients without sustained HBsAg clearance compared with none of the 20 recipients with sustained HBsAg clearance developed liver cirrhosis (12.9% vs 0%; P = .02 by log-rank). Our study showed that long-term hepatic complications occur in a significant proportion of HBsAg+ patients after HSCT and the incidence of liver cirrhosis is reduced in those with sustained serologic clearance of HBsAg after HSCT.

Patients with and without loss of hepatitis B virus DNA after hepatitis B e antigen seroconversion have different virological characteristics

The characteristic differences between patients with and without loss of hepatitis B virus (HBV) DNA after achieving hepatitis B e antigen seroconversion were analyzed by comparing changes in HBV DNA and HBV core-related antigen levels during a period from 3 years before to 3 years after the seroconversion. Of the 24 seroconverters, 6 (inactive replication group) showed continuous loss of HBV DNA in serum after the seroconversion and the remaining 18 did not lose HBV DNA (active replication group). The HBV DNA level was similar between the two groups, while the HBV core-related antigen level was significantly lower in the active replication group than in the inactive replication group before the seroconversion. The levels of both HBV DNA and HBV core-related antigen decreased remarkably around the time of seroconversion in the inactive replication group, while these levels did not change or decreased slightly in the active replication group. After the seroconversion, the HBV DNA level was significantly higher in the active replication group than in the inactive replication group, while the HBV core-related antigen level was similarly low between the two groups. Because the serum level of HBV core-related antigen mainly reflects that of HBe antigen, the low level of HBV core-related antigen seen after seroconversion in both groups might have contributed to the occurrence of seroconversion. The precore and core promoter mutations which cause diminished excretion of hepatitis B e antigen were significantly more frequent in the active replication group than in the inactive replication group. It was therefore considered that the seroconversion was caused mainly by a decrease in viral replication in the inactive replication group, and mainly by a decrease in HBe antigen production in the active replication group.

Nucleotide mutations associated with hepatitis B e antigen negativity

One hundred and forty four patients with chronic hepatitis B were tested to identify new mutations associated with hepatitis B e antigen (HBeAg) negativity, using a full genome sequence analysis. All the patients were Chinese and had hepatitis B virus infection of genotype C. Patients with none of the pre-core or core promoter mutations were significantly (P < 0.001) less common in the group with anti-HBe (13%) than in the group with HBeAg (56%). The complete nucleotide sequence was determined in four anti-HBe-positive patients who had neither pre-core nor core promoter mutations and in five HBeAg-positive patients who also had neither of these mutations (the groups were matched for age and sex). Six mutations were found to be significantly more common in the former group than in the latter: G529A (3/4 vs. 0/5), C934A (4/4 vs. 1/5), A1053G (4/4 vs. 1/5), G1915T/A (4/4 vs. 0/5), T2005C/A (4/4 vs. 0/5), and C3026T (3/4 vs. 0/5). Three of the six mutations were significantly more common in the four anti-HBe-positive patients who had neither pre-core nor core promoter mutations, compared to 11 HBeAg-positive patients who had pre-core and core promoter mutations, and also compared to 15 anti-HBe-positive patients who had pre-core and core promoter mutations, suggesting further the specificity of these mutations. Of the six mutations, two resulted in amino acid substitution in the polymerase protein, and one is located near the enhancer I region. The results suggest that the six newly discovered mutations are associated with HBeAg negativity.

Four years of lamivudine treatment in Chinese patients with chronic hepatitis B

BACKGROUND AND AIMS

This study assessed the efficacy and safety of up to 4 years of lamivudine treatment and the clinical relevance of the emergence of YMDD-variant hepatitis B virus (HBV).

METHODS

Fifty-eight Chinese adult patients with chronic hepatitis B (CHB) were randomized to lamivudine 100 mg/day for up to 5 years and were monitored for YMDD-variant HBV, hepatitis B e antigen (HBeAg) seroconversion (loss of HBeAg and detectable antibody to HBeAg) and serum alanine aminotransferase (ALT) concentrations. Four-year data are reported here.

RESULTS

The rate of HBeAg seroconversion increased with extended therapy and also with higher baseline ALT concentrations. YMDD-variant HBV was detected in 67% (39/58) of patients at some point during treatment. After 4 years, a total of 47% (27/58) of patients achieved HBeAg seroconversion. Thirty-three per cent (13/39) of patients with YMDD-variant HBV achieved HBeAg seroconversion; this increased to 57% (8/14) in patients with moderately elevated (>2-5 x upper limit of normal) pre-treatment ALT concentrations. The proportion of patients that achieved normal serum ALT increased from 29% (17/58) at baseline to 69% (31/45) following 4 years of treatment. That included 68% (23/34) of patients with YMDD-variant HBV and 73% (8/11) of those without the variant. All patients receiving lamivudine had reduced serum concentrations of HBV-DNA compared with baseline, despite the emergence of YMDD-variant HBV in 39 patients. Lamivudine was generally well tolerated; there was little change in the number or type of drug-related adverse events in the fourth year of the study.

CONCLUSIONS

Despite the emergence of YMDD-variant HBV, Chinese patients showed increased HBeAg seroconversion and improvement in ALT levels with an increased duration of treatment with lamivudine.

Beneficial effects of 'lamivudine pulse' therapy in HBeAg-positive patients with normal ALT*

Currently no therapy is given to patients with chronic hepatitis B virus (HBV) infection who are HBeAg positive with normal alanine aminotransferase (ALT) levels. Steroid priming has been shown to enhance T-helper-1 (Th-1) cell response. Lamivudine may restore immunologic competence against HBV by causing a sudden decline in the level of the virus. We examined the efficacy of lamivudine pulse therapy on the seroconversion from HBeAg to anti-HBe. This was a prospective single-blinded trial including 27 patients with chronic hepatitis B, HBeAg positive with ALT < or =1.5 times upper limit of normal (ULN). Lamivudine was administered initially for 4 weeks, then stopped for 2 weeks and later restarted and continued till 3 months after seroconversion or completion of 2 years of therapy. Twenty-six patients completed the study. Lamivudine withdrawal led to a rise in ALT levels above the ULN in 11 (42.3%) patients at 6 weeks; seven of them (63.6%) lost HBeAg compared with only two of the 15 patients (13.3%), in whom ALT levels did not rise (P = 0.011). As one patient showed a relapse, a total of eight (31%) patients responded to lamivudine pulse therapy over a mean period of 17.3 +/- 4.5 months. Responders had a higher serum albumin (P < 0.05), a lower fibrosis score (P < 0.05), and a relatively high baseline serum ALT levels (P = 0.024) than the nonresponders. YMDD mutations developed in three patients and none responded. No patient developed hepatic decompensation. Hence lamivudine pulse therapy has potential in converting HBeAg-positive, 'not-treat-worthy' (ALT < 1.5 ULN) patients to treat-worthy (ALT > 1.5 ULN) in 42%, with sustained HBeAg and HBV DNA loss in 31% patients. The effects are possibly because of a combination of antiviral and immunomodulating activities of lamivudine.

Efficacy and safety of lamivudine treatment for chronic hepatitis B in pregnancy

AIM: To evaluate the efficacy and safety of lamivudine treatment of chronic hepatitis B disease in pregnancy.

METHODS: The study group was comprised of 38 chronic HBV patients who were diagnosed pregnant during lamivudine treatment and voluntary to continue the same therapy. The control group was from documented patient data in the literatures. We compared the following parameters with those of a control group: anti-HBV efficacy, complications of pregnancy (abortion, preterm birth, neonatal asphyxia, fetal death, and congenital anomaly), incidence of HBV-positive babies and developmental anomalies in pregnant women treated with lamivudine.

RESULTS: The blocking rate of lamivudine treatment was significantly higher than that of active vaccine immunization for babies with double-positive (HBsAg/HBeAg) mothers with 30-30-10 µg doses of vaccine (74.07%) and with 30-20-10 µg (64.87%). The natural vertical HBV transmission from mother to infant of “double-positive” mothers was 100% (10/10). No pregnancy complication was noted during the observation period, but in the control group the incidences of pregnancy complication were 16.67% (abortion), 43.02%(preterm), 15.62% (neonatal asphyxia), and 4.49% (fetal death), 10.0% (congenital anomaly). No HBV-positive newborn was detected and no developmental anomaly was found in the study group.

CONCLUSION: Lamivudine is helpful to prevent maternal-infant HBV transmission and may reduce the complications of HBV-infected pregnant patients.

Serological detection of hepatitis B viral infection by a panel of solid-phase enzyme-linked immunosorbent assays (ELISA)

Immunoassays for the detection of hepatitis B virus (HBV) in biological samples were developed. Using recombinant HBV antigens (Ags) and HBV-specific antibodies (Abs), we designed and evaluated a panel of enzyme-linked immunosorbent assays (ELISAs) detecting the main hepatitis B-related viral markers, namely HBV surface Ag (HBsAg), HBV e Ag (HBeAg), Abs to HBsAg (anti-HBs), Abs to HBV core Ag (anti-HBc) and Abs to HBeAg (anti-HBe), in blood serum. The ELISAs were validated using a panel of prescreened, by commercial tests, serum samples. In principle, HBV Ags or anti-HBV monoclonal antibodies (mAbs) were immobilised on microplate wells. Horseradish peroxidase (HRP) or biotin were used to prepare labeled Abs. Specifically for the determination of HBsAg and HBeAg, two-site sandwich immunoenzymometric assays were developed. The useful range was estimated at 20-500 ng/ml and human serum samples assayed were diluted 10- and 4-fold for HBsAg and HBeAg, respectively, with phosphate buffered saline (PBS) containing Tween 20 and gelatin. For the detection of Abs to HBs an indirect ELISA was formulated. Sera were similarly 4-fold diluted in the same buffer. Finally, competitive ELISAs were used for detecting anti-HBc and anti-HBe and sera tested were diluted 20- and 5-fold, respectively. All selected dilutions resulted in the accurate and reliable determination of HBV Ags and anti-HBV Abs. Taken altogether, these ELISAs are highly specific and equally sensitive to the circulating tests. However, their design could be very useful for research and/or preclinical studies of selected HBV-infected individuals.

Results of lamivudine trials in Asia

In summary, 100 mg daily lamivudine therapy is safe and effective in Asian patients in terms of HBV suppression, ALT normalization and improvement in histology. The complete response rate after 1 year of lamivudine therapy is only around 15% but increases with increasing duration of treatment and increasing pretherapy ALT levels. Similar results were observed in patients with HBeAg-negative chronic hepatitis but published data are limited. YMDD mutations may emerge after 6-9 months of lamivudine therapy and its incidence also increases with increasing duration of therapy. The emergence of YMDD mutations is associated with viral and biochemical breakthrough. Hepatitis flares, sometimes associated with hepatic decompensation, may develop after stopping lamivudine therapy and in patients with YMDD mutations during continuing lamivudine therapy. The benefit of long-term lamivudine therapy therefore must be weighed carefully against the concern about YMDD mutations and the durability of therapeutic response. The development of new strategies, including selection of patient and timing of therapy, and new drugs are needed to further improve the therapeutic efficacy.

Living donor liver transplantation: Eastern experiences

The techniques of living donor liver transplantation (LDLT) developed rapidly in the 1990s to compensate for a severe deficiency in the availability of liver grafts from cadaveric donors for the treatment of patients with end-stage liver disease. This tendency was particularly prominent in East Asia, as brain-death donors have remained largely unavailable for a variety of reasons. Thanks to refinements in surgical technique and postoperative management for LDLT, the cumulative total of LDLTs in East Asian countries has exceeded 2000 and, importantly, donor mortality has yet to be encountered. Moreover, indications for LDLT have been successfully expanded from paediatric to adult cases, following the introduction of right lobe graft. The significance of LDLT under conditions of limited opportunities for cadaveric liver transplantation, as experienced in these countries, differs significantly from that seen with the numerous opportunities for cadaveric donors in Europe and the USA. This review describes not only the experiences of East Asia, but also the specific differences from Western countries, such as indications, graft size issues and ABO blood type combinations, to shed light on the future of liver transplantation.

High prevalence of occult hepatitis B in Baltimore injection drug users

Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in a serum or liver in the absence of hepatitis B surface antigen (HBsAg). The prevalence and clinical correlates of occult hepatitis B remain incompletely defined. A cross-sectional study was performed to determine the prevalence of occult hepatitis B in a high-risk cohort composed of 188 injection drug users in Baltimore, Maryland. All individuals had chronic hepatitis C viral infections confirmed by RNA detection and liver biopsy. Serologic assays for HBsAg and core antibody (HBcAb) were performed. Serum HBV DNA was detected using the COBAS HBV AMPLICOR monitor assay (lower limit of detection, 200 HBV copies per milliliter) and a semi-nested polymerase chain reaction (PCR) assay (lower limit of detection, 15 HBV copies per milliliter). Although almost all individuals (96%) were anti-HBC positive, only 8 of 188 (4%) were HBsAg positive. Occult hepatitis B was not identified using the COBAS assay, but was found in 81 of 180 (45%) of individuals using semi-nested PCR. Of the 8 HBsAg positive individuals, HBV DNA was found in 1/8 using the COBAS assay and 6/8 using the nested PCR assay. Overall, liver disease was mild, with a median serum alanine aminotransferase (ALT) of 38 IU/L, median activity grade of 3/18, and median fibrosis stage of 1/6. No association was found between the serum AST (aspartate aminotransferase), activity grade, or stage of liver disease and the presence of occult hepatitis B. Serum ALT levels were slightly higher in patients without occult hepatitis B (46 vs. 35 IU/L), and the median years since first injection drug use was somewhat longer in those without occult hepatitis B (24 vs. 20 years). In conclusion, although further research is needed to assess its clinical significance, there is a high prevalence of occult HBV infection in this cohort of HCV-infected injection drug users.

Review article: current management of chronic hepatitis B

Chronic hepatitis B can be diagnosed in patients with increased aminotransferases, hepatitis B virus viraemia and necroinflammation with fibrosis on liver biopsy. Although, ideally, all patients with chronic hepatitis B should be treated, therapeutic intervention is currently recommended for cases with a relatively satisfactory likelihood of response and/or advanced disease. A realistic therapeutic approach aims to sustain hepatitis B e antigen (HBeAg) loss and hepatitis B e antibody (anti-HBe) seroconversion in HBeAg-positive chronic hepatitis B and to sustain biochemical and virological remission in HBeAg-negative chronic hepatitis B. Currently, three drugs are licensed for chronic hepatitis B: interferon-alpha, lamivudine and adefovir dipivoxil. In patients with HBeAg-positive chronic hepatitis B, all of these drugs achieve HBeAg loss (24-33%) and anti-HBe seroconversion (12-30%) rates significantly superior to those observed in untreated placebo controls. In patients with HBeAg-negative chronic hepatitis B, the sustained off-therapy response rate is 20-25% after a > or =12-month course of interferon-alpha and minimal (<10%), if any, after a 12-month course of lamivudine or adefovir. Long-term lamivudine induces an initial response in 70-90% of patients, but only 30-40% of patients remain in remission after the third year due to progressively increasing viral resistance. Long-term adefovir achieves a response in approximately 70% of patients at 12 months, which is maintained at 24 months with rare (<2%) drug resistance. Adefovir is also effective against lamivudine-resistant strains. Many other anti-viral agents, immunomodulatory approaches and combination therapies are currently being evaluated in chronic hepatitis B.

[Prevalence of hepatitis B virus markers within household contacts in the State of Amazonas]

The aim of our investigation was to evaluate, with a prevalence study, the modes of transmission of Hepatitis B virus (HBV), within infected subjects and their household contacts in the State of Amazon, western Brazilian Amazon. We studied 97 index cases and 258 household contacts. Out of the 258 household contacts of HBV, 51.6% had serological markers of a past infection, 12.0% signs of active infection, suggesting that the virus circulates within household members. The high prevalence among siblings (23.6%) demonstrates the importance of personal contact in the transmission of this virus. Another indirect indicator of intra-familial transmission was the high prevalence of HBV markers within contacts of a fulminant hepatitis. The vertical transmission of HBV in our region may or may not occur, but if it does it as a rare event. Our results demonstrate the importance of the presence of HBV, and demand other investigations to clarify the inter-familial transmission of these viruses in our region.

Use of prophylactic lamivudine and mycophenolate mofetil in renal transplant recipients with chronic hepatitis B infection

Chronic HBsAg carriers are known to have a higher risk of hepatitis-related mortality and morbidity when undergoing kidney transplantation. Immunosuppressants might flare up the infection that could be fulminating. Lamivudine and mycophenolate mofetil (MMF) have been shown to be effective in inhibiting replication of hepatitis B virus (HBV). With these two drugs, hepatitis related adverse outcome might be preventable when these patients are being transplanted. Four Chinese adolescents with chronic HBV infection were transplanted in our Department from 1999 to 2001. Immunosuppresants included prednisolone, cyclosporin A and MMF; azathioprine was not used for its potentially liver toxic effect. Prophylactic lamivudine 3 mg/kg and maximum 100 mg daily was given just before transplantation and was continued afterwards. HBV status and liver enzymes were monitored serially. Patients were followed up for 26.0 +/- 10.3 (11-34) months post-transplant and no mortality was reported. All grafts were functioning and no rejection was noted. MMF and lamivudine were well tolerated. Alanine transaminase was only transiently elevated in the first 2 months post-transplant in all patients and became normal afterwards. The patients were clinically well and liver function was normal at the last follow-up. However, HBV DNA became positive in three patients after the transplantation. YMDD mutant HBV was negative in one patient and undeterminable in the other three due to low virus load. In summary, with prophylactic lamivudine and MMF, short-term follow-up showed that renal transplant might be feasible and safe in chronic HBV carriers.

Hepatitis B virus vaccination of recipients and donors of allogeneic peripheral blood stem cell transplantation

BACKGROUND

The aim of this study was to determine the role of hepatitis B virus (HBV) vaccination as defined by the seroconversion to hepatitis B surface antibody (anti-HBs) positivity in peripheral blood stem cell transplants.

METHODS

A total of 65 recipients and their donors were enrolled in this study. Recipients were divided into four distinct groups. Group 1 consisted of individuals who were vaccinated, group 2 consisted of individuals who were naturally immunized, group 3 consisted of individuals who were HBs-Ag positive, and group 4 consisted of individuals who were HBV naïve and not vaccinated.

RESULTS

Eighty-eight percent of the HBV-vaccinated recipients (14 of 16), who had vaccinated-donors, seroconverted to anti-HBs positivity. Eighty-three percent of HBV-naïve recipients (five of six), who received stem cells from HBV-immune donors, seroconverted to anti-HBs positivity. Two of the four HBs-Ag positive recipients with HBV-immune donors seroconverted to anti-HBs positivity after transplantation. Fifty-seven percent of previously vaccinated-recipients (eight of 14) lost detectable anti-HBs antibody following transplantation. Finally, 31% of HBV-naïve recipients with HBV-naïve donors acquired a de novo HBV infection.

CONCLUSIONS

(i) Hepatitis B virus immunization of recipients of allogeneic hematopoietic cell transplantation results in an effective antibody response. (ii) The HBV-immune status of the donor plays an important role in post-transplantation HBs-Ab on seroconversion. (iii) Systematic re-immunization of recipients will be necessary to maintain HBV immunity in long-term serving recipients.

Safety and outcome of hepatitis B core antibody-positive donors in right-lobe living donor liver transplantation

We studied the safety of right-lobe donor hepatectomy in living donors with a positive serological test result for antibody against hepatitis B core antigen (anti-HBc). Of 54 right-lobe living liver donors, serum anti-HBc was positive in 29 donors (54%) and negative in 25 donors (46%). None had a history of hepatitis and all had normal liver biochemistry test results before surgery. Surgical data, postoperative liver function, and outcome of donors were compared according to anti-HBc status. Donors positive for anti-HBc were significantly older (median age, 42 v 31 years; P <.001), but there was no difference in other demographics and liver size. Median blood loss was greater in anti-HBc-positive donors (600 v 350 mL; P =.007). Histological examination showed no difference in degree of portal fibrosis or fatty change in liver grafts. There was no significant difference in postoperative serum transaminase levels or prothrombin times; however, anti-HBc-positive donors had greater serum bilirubin levels day 6 (26 v 21 micromol/L; P =.01) and day 7 (22 v 15 micromol/L; P =.004) after surgery. Postoperative complications developed in 10 anti-HBc-positive and 6 anti-HBc-negative donors (P =.4). All donors who developed cholestasis were positive for anti-HBc, aged 45 years or older, and had mild fatty changes of the liver. Hospital stays were similar. All donors had completely normal liver function at a median follow-up of 31 months (range, 21 to 76 months). A positive serological test result for anti-HBc should not be regarded as a contraindication for right-lobe liver donation.

Clinical evaluation of a new enzyme immunoassay for hepatitis B virus core-related antigen; a marker distinct from viral DNA for monitoring lamivudine treatment

We aimed to assess the clinical performance of a newly developed chemiluminescence enzyme immunoassay (CLEIA) for the detection of hepatitis B virus (HBV) core-related antigen (HBcrAg) in patients with chronic HBV infection. A total of 82 patients with chronic HBV infection and 167 HBV-negative controls were studied. HBcrAg was measured by CLEIA with monoclonal antibodies to hepatitis B e antigen (HBeAg) and hepatitis B core antigen (HBcAg), and HBV DNA was measured by transcription-mediated amplification assay (TMA) and in-house real-time detection polymerase chain reaction (RTD-PCR). The HBcrAg assay detected viremia in 189 of 216 samples (88%) collected from 72 patients whilst the TMA assay detected viremia in 178 of the 216 samples (82%) (P = 0.019). The HBcrAg concentration correlated linearly with the HBV DNA concentration (P < 0.001) over a range which varied 100 000-fold. The accuracy in the measurement of the patients' HBV load obtained using the HBcrAg assay was not affected by the absence of hepatitis B e antigen from the serum or the presence of precore mutations in the HBV genome. In patients without anti-viral drugs, changes in their serum HBcrAg concentration over time corresponded to their HBV DNA concentration. In six additional patients who were later treated with lamivudine, HBV DNA concentration declined more rapidly than their HBcrAg concentration. Three months after treatment commenced, the ratio of HBcrAg: HBV DNA had increased in all six patients (P = 0.031). The HBcrAg assay is a sensitive and useful test for the assessment of a patient's HBV load. When monitoring the anti-viral effect of lamivudine, HBcrAg provides a viral marker which is independent of HBV DNA.

Long-term alpha interferon and lamivudine combination therapy in non-responder patients with anti-HBe-positive chronic hepatitis B: results of an open, controlled trial

AIM

To investigate the safety and efficacy of long-term combination therapy with alpha interferon and lamivudine in non-responsive patients with anti-HBe-positive chronic hepatitis B.

METHODS

34 patients received combination treatment (1 month lamivudine, 12 month lamivudine+interferon, 6 month lamivudine), 24 received lamivudine (12 months), 24 received interferon (12 months). Interferon was administered at 6 MU tiw and lamivudine at 100 mg orally once daily. Patients were followed up for 6 months after treatment.

RESULTS

At the end of treatment, HBV DNA negativity rates were 88 % with lamivudine+interferon, 99 % with lamivudine and 55 % with interferon, (P=0.004, combination therapy vs. interferon, and P=0.001 lamivudine vs. interferon), and serum transaminase normalization rates were 84 %, 91 % and 53 % (P=0.01 combination therapy vs. interferon, and P=0.012 lamivudine vs. interferon). Six months later, HBV DNA negativity rates were 44 % with lamivudine+interferon, 33 % with lamivudine and 25 % with interferon, and serum transaminase normalization rates were 61 %, 42 % and 45 %, respectively, without statistical significance. No YMDD variants were observed with lamivudine+interferon (vs. 12 % with lamivudine). The combination therapy appeared to be safe.

CONCLUSION

Although viral clearance and transaminase normalization are slower with long-term lamivudine+interferon than that with lamivudine alone, the combination regimen seems to provide more lasting benefits and to protect against the appearance of YMDD variants. Studies with other regimens regarding sequence and duration are needed.

Generation of stable cell lines expressing Lamivudine-resistant hepatitis B virus for antiviral-compound screening

Lamivudine [beta-L-(-)-2',3'-dideoxy-3'-thiacytidine] is a potent inhibitor of hepadnavirus replication and is used both to treat chronic hepatitis B virus (HBV) infections and to prevent reinfection of transplanted livers. Unfortunately, lamivudine-resistant HBV variants do arise during prolonged therapy, indicating a need for additional antiviral drugs. Replication-competent HBV constructs containing the reverse transcriptase domain L180M/M204V and M204I (rtL180M/M204V and rtM204I) mutations associated with lamivudine resistance were used to produce stable cell lines that express the resistant virus. These cell lines contain stable integrations of HBV sequences and produce both intracellular and extracellular virus. HBV produced by these cell lines was shown to have a marked decrease in sensitivity to lamivudine, with 450- and 3,000-fold shifts in the 50% inhibitory concentrations for the rtM204I and rtL180M/M204V viruses, respectively, compared to that for the wild-type virus. Drug assays indicated that the lamivudine-resistant virus exhibited reduced sensitivity to penciclovir [9-(4-hydroxy-3-hydroxymethyl-but-1-yl) guanine] but was still inhibited by the nucleoside analogues CDG (carbocyclic 2'-deoxyguanosine) and abacavir ([1S,4R]-4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclopentene-1-methanol). Screening for antiviral compounds active against the lamivudine-resistant HBV can now be done with relative ease.

Prophylaxis and treatment of recurrent hepatitis B after liver transplantation

Chronic hepatitis B virus (HBV) infection is the leading cause of end-stage liver disease in Asia. The results of liver transplantation in these patients have significantly improved to a level comparable to those of other recipients as a result of the rapid evolution in the strategies of prevention and treatment of recurrent hepatitis B over the past decade. Hepatitis B immune globulin (HBIG) and lamivudine, either alone or in combination, are effective in preventing reinfection, but the most cost-effective dosing regimen with optimum efficacy without the prohibitive cost remains to be determined, an issue that is particularly relevant to liver transplant centers with serious financial constraints in Asia. The idea of active immunization is attractive, but the results have been conflicting to date. The newer nucleoside analogs appear most promising, and a combination of two or more antiviral agents is likely to represent the future strategy of choice in the prophylaxis and treatment of recurrent hepatitis B after liver transplantation.

Detection of hepatitis B virus in seropositive and seronegative patients with chronic liver disease using DNA amplification by PCR

BACKGROUND

The aim of this study was to detect DNA of hepatitis B virus (HBV) for reliable diagnosis of HBV infection in sera by means of a validated polymerase chain reaction (PCR) using a 5' oligonucleotide (primer) previously described and a 3' primer designed by our investigation group.

METHODS

Sera samples collected from patients with chronic liver disease (CLD) related to HBV infection and negative to hepatitis C virus (HCV) infection were analyzed. Patients were both positive and negative to HBV by serum markers detected by ELISA immunoassay. A 146-base pair (bp) fragment was amplified from highly conserved precore-core region. This procedure enabled us to search for DNA HBV-positive cases.

RESULTS

Viral replicative state in negative hepatitis B e antigen (HBeAg) (15.7%) cases was verified by PCR technique. This detected infection by HBV in 100% of immunoassay-positive samples. Additionally, sequences of expected size in patients bearing atypical markers in their sera (7.1%) and those with negative serology (4.8%) for HBV markers were detected.

CONCLUSIONS

In this study we have improved a PCR technique successfully applied in hepatitis B prevalence studies in northeastern Mexico. Prevalence of hepatitis B in this region of Mexico is intermediate compared to countries of the northern hemisphere where prevalence is lower, and to countries of Southeast Asia and the Mediterranean region where it is highly endemic.

Long-term lamivudine therapy for chronic hepatitis B in patients with and without cirrhosis

STUDY OBJECTIVE

To evaluate the effects and safety of 52-week lamivudine therapy in Korean patients with chronic hepatitis B virus (HBV), with and without cirrhosis.

DESIGN

Long-term retrospective study.

SETTING

Ajoo University Medical Center, Soowon, Korea.

PATIENTS

Twenty-seven men and two women who had received oral lamivudine 100 mg/day for 52 weeks for treatment of biopsy-proven chronic HBV; 11 patients had cirrhosis, 18 did not.

MEASUREMENTS AND MAIN RESULTS

All 29 patients were positive for HBV DNA and hepatitis B surface antigen (HBsAg) before treatment began; 25 (86%) patients were positive for hepatitis B e antigen (HBeAg). Lamivudine therapy suppressed serum HBV DNA to undetectable levels in 26 (90%) patients within a median of 4 weeks. Serum HBV DNA of 28 patients (97%) fell significantly to undetectable levels within 12 weeks and remained undetectable in 24 (83%) patients after 52 weeks, and HBeAg had converted to negative in 10 (40%) of the 25 patients who were positive. Mean serum alanine aminotransferase (ALT) levels of the 29 patients decreased to within the normal range by 12 weeks and remained at 33-48 IU/L thereafter. Differences in responses of HBV DNA and ALT to lamivudine therapy in HBeAg-positive and -negative patients were negligible (p = 0.786 and p = 0.225, respectively). Pretreatment HBV DNA and ALT levels had no effect on the efficacy of lamivudine (p = 0.9116). Furthermore, differences in responses of HBV DNA (p = 0.641), HBeAg seroconversion (p = 0.386), and ALT (p = 0.689) and in development of drug resistance (p = 0.617) between patients with and without cirrhosis were negligible. No serious adverse effects were reported.

CONCLUSION

Lamivudine is an effective and well-tolerated therapeutic agent for treating chronic HBV in patients with and without cirrhosis.

Evolving experience of hepatitis B virus prophylaxis in liver transplantation

Passive immunoprophylaxis with hepatitis B immunoglobulin (HBIG) is important to prevent recurrence of hepatitis B virus (HBV) after orthotopic liver transplantation (OLT) for chronic HBV cirrhosis. With availability of lamivudine (3TC), the use of combination prophylaxis with long-term HBIG/3TC has been shown to prevent short-term HBV recurrence. This report compares HBV recurrence rates between groups receiving no/short-term HBIG, long-term HBIG alone, or HBIG/3TC prophylaxis, and describes HBIG requirements during the first 6 and 12 months in the latter two groups. This study involved patients undergoing OLT at the University of Tennessee-Memphis between May 1990 and July 2001. During this period, 388 liver transplants were performed at our center. All hepatitis B surface antigen (HBsAg)-positive recipients (n = 27) were included in this retrospective analysis. The groups were similar with regard to pre-transplant demographic characteristics such as age, gender, weight, and pre-transplant diagnosis. Owing to the retrospective study design, median follow-up was longer for the no-prophylaxis (5.6 years) and the HBIG-alone (6.0 years) groups compared to the HBIG/3TC group (4.2 years). Patient survival was 50% in the no-prophylaxis and 71% in the HBIG-alone groups compared to 100% in the HBIG/3TC group (P = 0.09). When censored for death with a functioning graft, graft survival was 50% in the no-prophylaxis and 86% in the HBIG-alone group compared to 100% in the HBIG/3TC group (P = 0.07). The overall incidence of HBV recurrence in the no-prophylaxis era was 100% and 21% in the HBIG-alone era compared to 0% in the HBIG/3TC era (P < 0.001), despite similar mean and median HBIG trough titers in the HBIG-alone and HBIG/3TC groups. The incidence of HBV recurrence in HBV DNA-positive recipients was 100% in the no-prophylaxis era, 30% in the HBIG-alone era, and 0% in the HBIG/3TC era (P < 0.001). Recipients in the HBIG-alone group had a nearly two-fold increase in HBIG requirement at 6 and 12 months in order to maintain similar HBIG trough titers post-transplant compared to recipients in the HBIG/3TC group despite similar pre-transplant HBV serology. This increased HBIG requirement in the HBIG-alone group resulted in a marked increase in the mean overall cost of HBV prophylaxis in this group ($47,367 US dollars at 6 months; $84,280 US dollars at 12 months) compared to the HBIG/3TC group ($25,931 US dollars at 6 months; $49,599 US dollars at 12 months). These data demonstrate an improvement in patient and graft survival rates in the group receiving combination HBIG/3TC prophylaxis compared to the HBIG-alone and no-prophylaxis groups. There was a significant reduction in HBV recurrence in the group receiving combination HBIG/3TC when compared to the groups receiving HBIG alone or no prophylaxis. Furthermore, we demonstrated that the addition of 3TC to the long-term HBIG regimen led to elimination of the disparity previously described in HBV recurrence rates between HBV DNA-positive and HBV DNA-negative recipients. Importantly, our data demonstrates a complete lack of HBV recurrence in the HBIG/3TC group at a median follow-up of 4.2 years. Additionally, the data show that the addition of 3TC to the post-operative prophylaxis regimen resulted in a reduction in the requirement of HBIG at 6 and 12 months, which markedly reduced the overall cost of post-transplant HBV prophylaxis.

Occult hepatitis B

Worldwide, chronic hepatitis B virus (HBV) infection is the primary cause of cirrhosis and hepatocellular carcinoma and is one of the ten leading causes of death. Traditionally, people with chronic HBV infection have been identified with blood tests for HBV antigens and antibodies. Recently, another group of patients with chronic HBV infection has been identified by sensitive, molecular testing for HBV DNA. Members of this group are often referred to as having occult hepatitis B because they are HBV-DNA positive, but hepatitis B surface antigen negative. Occult hepatitis B occurs in a number of clinical settings. In this review, we examine occult hepatitis B in people co-infected with hepatitis C, in whom occult hepatitis B has been associated with advanced fibrosis and diminished response to interferon alpha. Although much more research is needed, existing reports justify a heightened awareness of the medical importance and means of testing for occult hepatitis B.

Nucleoside analogues for chronic hepatitis B: antiviral efficacy and viral resistance

Nucleoside analogues have been recently introduced in the management of chronic hepatitis B virus (HBV) infection. They mainly act by inhibition of HBV polymerase activity resulting in decrease of viral replication. They are administered orally, and most of them have an excellent tolerance and safety profile. Lamivudine is the only nucleoside analogue licensed for chronic hepatitis B. It has potent activity against HBV, and a 12-month course achieves clearance of hepatitis B e antigen (HBeAg) in 20-30% of HBeAg-positive patients and both biochemical and virological remission in more than 65-70% of HBeAg-negative chronic hepatitis B patients. Famciclovir and ganciclovir are less effective, whereas other nucleoside or nucleotide analogues, such as adefovir, entecavir, and emtricitabine, are currently under evaluation. Prolonged effective antiviral therapy is required for eradication of chronic HBV infection, but long-term treatment with nucleoside analogues has been found to be associated with progressively increasing rates of viral resistance because of emergence of resistant HBV mutant strains. Virological breakthroughs usually develop after the first 6 months of lamivudine monotherapy, and their rate ranges between 15% and 30% at 12 months and exceeds 50% after 3 yr of therapy. Resistant HBV mutant strains harbor point mutations in the HBV polymerase gene and predominantly in the well-conserved YMDD motif. Although resistant HBV strains may have impaired replication capacity compared with the wild HBV, their clinical significance has not been completely clarified yet. No significant biochemical or clinical event may develop in some cases, whereas severe biochemical breakthroughs with or without deterioration of liver function may develop in others. To date, there is no proven effective therapy for the resistant HBV mutant strains, although adefovir and entecavir seem to be interesting candidates.

Occult hepatitis B virus infection and its clinical implications

Occult hepatitis B virus (HBV) infection is characterized by presence of HBV infection with undetectable hepatitis B surface antigen (HBsAg). Serum HBV level is usually less than 104 copies/mL in these patients. Diagnosis of occult HBV infection requires sensitive HBV-DNA PCR assay. Several possibilities have been hypothesized as the mechanisms of occult HBV infection. These include: (i) mutations of HBV-DNA sequence; (ii) integration of HBV-DNA into host's chromosomes; (iii) infection of peripheral blood mononuclear cells by HBV; (iv) formation of HBV-containing immune complex; (v) altered host immune response; and (vi) interference of HBV by other viruses. The precise prevalence of occult HBV infection remains to be defined. The clinical implications of occult HBV infection involve different clinical aspects. First of all, occult HBV infection harbours potential risk of HBV transmission through blood transfusion, haemodialysis, and organ transplantation. Second, it may serve as the cause of cryptogenic liver disease, contribute to acute exacerbation of chronic hepatitis B, or even fulminant hepatitis. Third, it is associated with development of hepatocellular carcinoma. Fourth, it may affect disease progression and treatment response of chronic hepatitis C. Most of the previous studies utilized retrospective observation without control groups, and lacked direct association of occult HBV infection with specific pathological changes and disease progression. Highly sensitive, quantitative, and functional molecular analyses of HBV, combined with a well-designed prospective clinical assessment will provide the best approach for the future study of occult HBV infection.

Hepatitis B virus infection among Chinese residents in the United Kingdom

OBJECTIVE

To determine prevalence of hepatitis B virus (HBV) serological markers in Chinese residents in the United Kingdom.

METHOD

Retrospective case-controlled study between January 1997 and June 2000 in two genitourinary medicine (GUM) clinics.

RESULTS

117 Chinese and 234 non-Chinese controls were studied. Baseline characteristics except marital status showed no difference. Overall prevalence of HBV serological markers was 35.8% in Chinese, controls 5.5% (p<0.001). Hepatitis B surface antigen (HBsAg) positive carrier rate was 12.8% in Chinese, controls 0.4% (p<0.001); 1.7% of Chinese patients were also hepatitis B e antigen (HBeAg) positive, none in controls. Natural immunity was acquired in 23.0% of Chinese, controls 5.1% (p<0.001). Prevalence of HBV serological markers in UK born Chinese was 6.7%, non-UK born Chinese 40.1% (p<0.011). Only 7.6% of Chinese had a history of previous HBV vaccination.

CONCLUSIONS

Prevalence of HBV serological markers among Chinese patients attending two GUM clinics in London was high and only a minority of Chinese had immunisation against HBV. Although the prevalence of HBV markers in UK born Chinese was lower than non-UK born Chinese, they may be at continuous risk of HBV infection. Non-UK born Chinese patients attending GUM services in the United Kingdom should be targeted for screening and vaccination to reduce HBV transmission.

Pharmacology of beta-L-thymidine and beta-L-2'-deoxycytidine in HepG2 cells and primary human hepatocytes: relevance to chemotherapeutic efficacy against hepatitis B virus

beta-L-Thymidine (L-dT) and beta-L-2'-deoxycytidine (L-dC) are potent and highly specific inhibitors of hepatitis B virus (HBV) replication both in vivo and in vitro (50% effective concentrations, 0.19 to 0.24 microM in 2.2.15 cells). The intracellular metabolisms of L-dT and L-dC were investigated in HepG2 cells and primary cultured human hepatocytes. L-dT and L-dC were extensively phosphorylated in both cell types, with the 5'-triphosphate derivative being the predominant metabolite. In HepG2 cells, the 5'-triphosphate levels were 27.7 +/- 12.1 and 72.4 +/- 1.8 pmol/10(6) cells for L-dT and L-dC, respectively. In primary human hepatocytes, the 5'-triphosphate levels were 16.5 +/- 9.8 and 90.1 +/- 36.4 pmol/10(6) cells for L-dT and L-dC, respectively. Furthermore, a choline derivative of L-dCDP was detected at concentrations of 15.8 +/- 1.8 and 25.6 +/- 0.1 pmol/10(6) cells in human hepatocytes and HepG2 cells, respectively. In HepG2 cells exposed to L-dC, the 5'-monophosphate and 5'-triphosphate derivatives of beta-L-2'-deoxyuridine (L-dUMP and L-dUTP, respectively) were also observed, reaching intracellular concentrations of 6.7 +/- 0.4 and 18.2 +/- 1.0 pmol/10(6) cells, respectively. In human hepatocytes, L-dUMP and L-dUTP were detected at concentrations of 5.7 +/- 2.4 and 43.5 +/- 26.8 pmol/10(6) cells, respectively. It is likely that deamination of L-dCMP by deoxycytidylate deaminase leads to the formation of L-dUMP, as the parent compound, L-dC, was not a substrate for deoxycytidine deaminase. The intracellular half-lives of L-dTTP, L-dCTP, and L-dUTP were at least 15 h, with intracellular concentrations of each metabolite remaining above their respective 50% inhibitory concentrations for the woodchuck hepatitis virus DNA polymerase for as long as 24 h after removal of the drug from cell cultures. Exposure of HepG2 cells to L-dT in combination with L-dC led to concentrations of the activated metabolites similar to those achieved with either agent alone. These results suggest that the potent anti-HBV activities of L-dT and L-dC are associated with their extensive phosphorylation.

Survival and prognostic indicators in patients with hepatitis B virus-related cirrhosis after onset of hepatic decompensation

GOALS

To determine the 2-year survival and prognostic indicators of hepatitis B virus-related cirrhosis after the onset of hepatic decompensation.

BACKGROUND

Chronic hepatitis B (CHB) patients with cirrhosis and resultant hepatic decompensation have reduced survival. However, the natural history of these patients has not been well characterized in previous studies. Better understanding of survival and prognostic indicators is essential in management of these patients, especially in determining who should be candidates for orthotopic liver transplantation.

STUDY

This is a retrospective longitudinal study of 96 patients with CHB-related cirrhosis after the onset of hepatic decompensation. The overall survival was ascertained, and clinical and laboratory variables were analyzed. Significant prognostic indicators for survival at 2 years were determined using univariate and multivariate analyses with Cox regression model.

RESULTS

The overall survival was 80% at 2 years after onset of decompensation. With univariate and multivariate analyses, hepatic encephalopathy and hypoalbuminemia less than 2.8 g/dL were significant prognostic indicators of poor survival probability. The hazard ratios were 5.22 (95% confidence interval, 1.67-16.3) and 8.57 (95% confidence interval, 1.94-37.8), respectively. Patients with hypoalbuminemia less than 2.8 g/dL had a 2-year survival of only 62%.

CONCLUSIONS

Our study showed that of CHB patients who developed the first episode of hepatic decompensation, those with hepatic encephalopathy or significant hypoalbuminemia or both have worse prognoses. They should be considered potential candidates for liver transplantation.

Chronic hepatitis B infection in Canada

Recent developments in the treatment and prevention of hepatitis B virus (HBV) infections warrant revisiting important epidemiological questions, such as how prevalent is chronic HBV infection in Canada, in which Canadian subpopulations are HBV prevalence rates the highest, in what percentage of infected individuals is the virus actively replicating, and how many infected Canadians are candidates for antiviral therapy? Currently available data suggest the overall prevalence of HBV-infected individuals in the general population is approximately 2%, with 5% to 10% having serological evidence of previous HBV infection. In high risk groups, such as street-connected individuals, Aboriginals and immigrants from endemic areas, these rates of viral prevalence and serological evidence of previous HBV infection are approximately two to 10 and five to 10 times higher, respectively, than in the general population. Candidates for antiviral therapy range from less than 1% of infected Aboriginals to 15% to 30% of Asians with chronic HBV. From these data, it is clear that chronic HBV remains an important public health problem in this country. Hence, resources must be identified to enhance Canadians' awareness of HBV infection, maintain, if not expand, efforts to identify and implement safe and effective antiviral therapy for HBV-infected individuals, and continue programs for universal vaccination to prevent new HBV infections.

Diagnosis and management of pre-core mutant chronic hepatitis B

Chronic hepatitis due to pre-core hepatitis B virus (HBV) mutants presents as hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB). HBeAg-negative CHB represents a late phase in the natural course of chronic HBV infection that develops after HBeAg loss and seroconversion to anti-HBe. It is usually associated with pre-core stop codon mutation at nucleotide 1896 (mainly selected in non-A HBV genotypes), but also with other pre-core changes or with mutations in the basic core promoter region (mainly in HBV genotype A). In chronic HBV infections, pre-core mutants can be detected both in patients with HBeAg-negative CHB and in inactive hepatitis B surface antigen (HBsAg) carriers. The diagnosis of HBeAg-negative CHB is based on HBsAg positivity, HBeAg negativity, and mainly on increased alanine aminotransferase (ALT) and serum HBV-DNA levels and exclusion of other causes of liver disease. The differential diagnosis between patients with CHB and inactive HBsAg carriers can be made only by close follow-up of aminotransferase activity and viraemia levels, although the cut-off level of serum HBV DNA has not been definitely determined. IgM anti-HBc levels have also been suggested as an index that increases the diagnostic accuracy for transient hepatitis flares, while liver biopsy confirms the diagnosis and evaluates the severity of the liver disease. Interferon-alpha (IFN-alpha) and lamivudine are the two drugs that have been tried, mainly in the management of HBeAg-negative CHB. A 12-month course of IFN-alpha achieves sustained biochemical remission in about 20% of patients, which has been associated with improvement in the long-term outcome of this subset. A 12-month course of lamivudine is rather ineffective, maintaining remission in less than 15% of patients after cessation of therapy. Long-term lamivudine is associated with progressively increasing rate of virological and subsequent biochemical breakthroughs due to YMDD mutants, with approximately 30% of patients remaining in remission in the third year of therapy. Several other antiviral agents are currently being evaluated in this setting with combined regimens being the most reasonable step for the near future.