Changes of serum hepatitis B virus DNA and aminotransferase levels during the course of chronic hepatitis B virus infection in children

Spontaneous loss of chronic HBV infection markers in treatment-naïve children: a systematic review and pooled meta-analyses

Objectives: Chronicity could be a serious threat to hepatitis B virus (HBV)-infected children. The necessity of antiviral treatment to HBV-infected children has caused much controversy. The authors aimed to conduct a systematic review and meta-analysis of synthesized evidence regarding the spontaneous loss of chronic HBV infection markers in treatment-naïve children for exploring their long-term management.Methods: Observational cohort studies and non-treatment arms of randomized controlled trials were searched that reported the spontaneous loss of chronic HBV infection markers in untreated children (characterized by the presence of HBsAg ≥6-month), via the rates of hepatitis B surface antigen (HBsAg) loss, hepatitis B e antigen (HBeAg) seroconversion, and HBV DNA suppression with random-effects model.Results: Of 7,427 studies screened, 20 were included in meta-analysis. With cumulative 23,153 person-years of follow-up, the pooled annual incidences of HBsAg and HBeAg loss, HBV DNA suppression were 1, 6, 7%, respectively. Rates within HBeAg loss and HBV DNA suppression did differ by the transmission modes and ALT levels, not in HBsAg.Conclusion: Spontaneous HBsAg loss (function cure) occurs infrequently in treatment-naïve children with chronic HBV infection. Design of practically applicable programs aiming at therapeutics of children may be necessary to support the goal of eliminating HBV infection worldwide.

[Natural History and Treatment Indications of Chronic Hepatitis B]

HBV is the most common etiology of both liver cirrhosis and hepatocellular carcinoma in Korea. Despite much progress made, the currently available antiviral therapies cannot eradicate or eliminate this virus. Hence, the benefits and risks of antiviral therapy should be carefully evaluated on an individual basis and within the context of the clinical situation. The ultimate goals of treatment are to decrease the mortality from liver disease. The benefits of antiviral therapy come from prevention of progression of liver disease. Understanding the natural history of chronic HBV infection is a key step in the decision making process to treat patients with chronic HBV infection. Generally, chronic hepatitis B patients in the immune tolerant phase and immune inactive phase are not recommended to undergo antiviral treatment, except for those patients in special conditions (e.g., immunosuppression or anticancer chemotherapy). Chronic hepatitis B patients in the immune active phase are recommended for antiviral therapy. For patients with liver cirrhosis, treatment should be considered when serum HBV DNA is detectable regardless of the serum level of ALT.

Current role of transient elastography in the management of chronic hepatitis B patients

Liver fibrosis is an important prognostic factor for chronic hepatitis B (CHB), and accurate evaluation of the stage of liver fibrosis is crucial in establishing management strategies. While liver biopsy is still considered the gold standard for staging liver fibrosis or cirrhosis, transient elastography (TE), a noninvasive means of assessing liver fibrosis, has come to play an increasing role in this process. After extensive validation, TE is now regarded as a reliable surrogate maker for grading the severity of liver fibrosis in CHB patients. It can detect the extent of fibrosis in a patient and can also be used to evaluate longitudinal changes in liver fibrosis over time with or without interventional management, such as antiviral therapy. However, several confounders hinder the effective assessment of liver fibrosis using TE, such as extensive liver necroinflammation, hepatic congestion, and cholestasis. TE has limited use in obese patients or patients with ascites. Although TE has several limitations, due to its accessibility and safety, it is a valuable tool for the initial evaluation and follow-up in patients with CHB.

Challenges in the management of chronic HBV infection in West Africa: The clinician's perspective

BACKGROUND

Hepatitis B infection has become a public health issue in recent years. Approximately 350 million of the world's population are chronically infected reaching endemic proportions in West Africa. Guidelines for treatment are continuously improving but are becoming more complex.

AIM

To determine the challenges hepatologists experience in the management of patients with chronic hepatitis B.

METHODS

This was a cross-sectional descriptive study conducted among hepatologists in West Africa during a regional hepatitis conference in 2013.

RESULTS

Forty-six hepatologists completed the questionnaire. When evaluating a patient for chronic hepatitis B, the preferred investigations were: LFT (100%); abdominal ultrasound (93.5%); HBeAg (93.5%); HBV DNA (78%); HBsAg measure (22%); HBV genotype (15.2%); and liver biopsy (34.8%). Most had their patients on nucleoside/nucleotide analogue but follow-up visits after 1 year were problematic.

CONCLUSION

The majority of hepatologists had good intentions regarding the evaluation of their patients, but only a small percentage of patients are properly investigated.

KASL Clinical Practice Guidelines: Management of chronic hepatitis B

The guideline on the management of chronic hepatitis B (CHB) was first developed in 2004 and revised in 2007 by the Korean Association for the Study of the Liver (KASL). Since then there have been many developments, including the introduction of new antiviral agents and the publications of many novel research results from both Korea and other countries. In particular, a large amount of knowledge on antiviral resistance--which is a serious issue in Korea--has accumulated, which has led to new strategies being suggested. This prompted the new guideline discussed herein to be developed based on recent evidence and expert opinion.

TARGET POPULATION

The main targets of this guideline comprise patients who are newly diagnosed with CHB and those who are followed or treated for known CHB. This guideline is also intended to provide guidance for the management of patients under the following special circumstances: malignancy, transplantation, dialysis, coinfection with other viruses, pregnancy, and children.

TGF-β1 down-regulation of NKG2D/DAP10 and 2B4/SAP expression on human NK cells contributes to HBV persistence

The mechanism underlying persistent hepatitis B virus (HBV) infection remains unclear. We investigated the role of innate immune responses to persistent HBV infection in 154 HBV-infected patients and 95 healthy controls. The expression of NKG2D- and 2B4-activating receptors on NK cells was significantly decreased, and moreover, the expression of DAP10 and SAP, the intracellular adaptor proteins of NKG2D and 2B4 (respectively), were lower, which then impaired NK cell-mediated cytotoxic capacity and interferon-γ production. Higher concentrations of transforming growth factor-beta 1 (TGF-β1) were found in sera from persistently infected HBV patients. TGF-β1 down-regulated the expression of NKG2D and 2B4 on NK cells in our in vitro study, leading to an impairment of their effector functions. Anti-TGF-β1 antibodies could restore the expression of NKG2D and 2B4 on NK cells in vitro. Furthermore, TGF-β1 induced cell-cycle arrest in NK cells by up-regulating the expression of p15 and p21 in NK cells from immunotolerant (IT) patients. We conclude that TGF-β1 may reduce the expression of NKG2D/DAP10 and 2B4/SAP, and those IT patients who are deficient in these double-activating signals have impaired NK cell function, which is correlated with persistent HBV infection.

NK cells have been viewed as the most important effectors of the initial antiviral innate immune response. Their activation depends on the integration of signals from “co-activation” receptors, and the cytotoxic effects of NK cells on target cells are tempered by a need for combined signals from multiple activating receptors, such as NKG2D and 2B4. In this study, we showed that NKG2D and 2B4 expression levels were decreased on NK cells from patients in the IT phase of HBV infection. We further demonstrated that lower levels of intracellular adaptor proteins (DAP10 and SAP) were associated with lower surface expression of NKG2D and 2B4. As a result, the synergistically co-activated signalling pathway initiated by NKG2D and 2B4 did not operate properly in IT-phase patients. We demonstrated that high levels of soluble TGF-β1 were associated with the reduction of NKG2D and 2B4 in patients. In addition, we showed that TGF-β1 causes the cell-cycle arrest of NK cells by up-regulating the levels of p15 and p21 in NK cells from IT patients. Collectively, these findings may contribute to our understanding of the immune tolerance mechanism and aid in the development of novel therapeutic methods to clear HBV infection during the initial phase.

Management of chronic hepatitis B in children

Hepatitis B virus (HBV) infection is a worldwide problem and can cause acute liver failure, acute hepatitis, chronic hepatitis, liver cirrhosis, and liver cancer. In areas of high prevalence such as in Asia, Africa, southern Europe, and Latin America, the hepatitis B surface antigen positive rate ranges from 2% to 20%.In endemic areas, HBV infection occurs mainly during infancy and early childhood. Mother-to-infant transmission accounts for approximately half of the chronic HBV infections. In contrast to infection in adults, HBV infection during early childhood results in a much higher rate of persistent infection and long-term serious complications such as liver cirrhosis and HCC.Three phases of chronic hepatitis B have been identified: the immune-tolerant phase, the immune-active phase, and the inactive hepatitis B phase. These phases of infection are characterized by variations in viral replication, hepatic inflammation, spontaneous clearance, and response to antiviral therapy.The optimal goal of antiviral therapy for chronic HBV infection is to eradicate HBV and to prevent its related liver complications. However, due to the limited effect of available therapies in viral eradication, the goal of treatment is to reduce viral replication, to minimize liver injury, and to reduce infectivity. In this review the current recommendations for monitoring and treating chronic HBV infection in children are reviewed.

Viremia profiles in children with chronic hepatitis B virus infection and spontaneous e antigen seroconversion

BACKGROUND & AIMS

This study investigated the viremia profiles in children with chronic hepatitis B virus (HBV) infection and spontaneous hepatitis B e antigen (HBeAg) seroconversion.

METHODS

Fifty-eight children with chronic HBV infection met the following criteria: normal alanine aminotransferase (ALT) level at enrollment, followed up for more than 10 years, no antiviral treatment, and having undergone spontaneous HBeAg seroconversion during follow-up evaluation. They were grouped according to the post-HBeAg seroconversion HBV-DNA levels: (1) low viremia: transient or never 10(4) copies/mL or greater (n=35) (2) fluctuating high viremia: 10(4) copies/mL or greater at least twice at intervals more than 1 year apart (n=23). Abdominal sonography, ALT, and HBV-DNA levels were assessed annually. Another 14 nonseroconverted children served as controls. The precore mutant (nt1896) and genotypes were examined.

RESULTS

The initial HBV-DNA level of the 58 seroconverters was 10(8.4+/-1.0) copies/mL and decreased to 10(2.9+/-2.0) copies/mL at the end of follow-up period. Their mean ages at enrollment, at peak HBV-DNA, at peak ALT, at HBeAg seroconversion, and at final follow-up were 7.0 +/- 3.7, 13.4 +/- 5.8, 16.3 +/- 6.0, 17.2 +/- 5.8, and 23.7 +/- 4.1 years, respectively. The precore mutant appeared more often in the fluctuating-high-viremia group than in the low-viremia group (60.9% vs 22.9%, P=.004). HBV genotypes had no effect on the viremia profiles. After HBeAg seroconversion, none had persistent abnormal ALT levels.

CONCLUSIONS

Generally, these young seroconverters had decreased viral loads, normal ALT levels, and uneventful courses after HBeAg seroconversion. A longer follow-up period is necessary to elucidate the significance of HBeAg seroconversion occurring in childhood and young adulthood.

Chronic hepatitis B virus carriers in the immunotolerant phase of infection: histologic findings and outcome

BACKGROUND & AIMS

The indication for histologic evaluation of the liver is controversial for patients in the immunotolerant phase of chronic hepatitis B virus (HBV) infection.

METHODS

Results of liver biopsy examination and follow-up evaluation were assessed retrospectively in 40 patients who satisfied the following criteria: presence of hepatitis B surface antigen and hepatitis B e antigen, HBV DNA level greater than 10(7) cp/mL, normal alanine aminotransferase level, absence of co-infection with other viruses, and absence of antiviral or immunosuppressive treatment.

RESULTS

On liver biopsy examination, according to the Metavir scoring system, fibrosis was absent in 20 patients, and mild (F1) in 20 patients. During a median follow-up period of 37.7 months in 31 patients, loss of tolerance was observed at a median age of 30.7 years in 12 (38%): 6 had transition to inactive disease, 3 developed chronic hepatitis, and 3 had a transient increase of alanine aminotransferase levels. Among baseline characteristics, only alanine aminotransferase levels were significantly higher in patients with subsequent loss of tolerance.

CONCLUSIONS

In patients in the immunotolerant phase of chronic HBV infection, liver biopsy examination shows only minimal changes and probably is unnecessary. Loss of tolerance, occurring at a median age of 30.7 years, is characterized by a rapid transition to an inactive carrier state in two thirds of patients, and to chronic hepatitis in one third of patients.

Relationship between viral load and genotypes of hepatitis B virus in children with chronic hepatitis B

OBJECTIVE

We evaluated the prevalence and clinical significance of hepatitis B virus (HBV) genotypes in children with chronic hepatitis B.

METHODS

Hepatitis B virus genomes of 249 hepatitis Be antigen-positive chronic hepatitis B surface antigen carriers were genotyped based on restriction fragment length polymorphism. Genotypes were correlated with corresponding values for alanine aminotransferase levels, quantitative HBV DNA and histological findings.

RESULTS

One hundred and sixty-two boys and 87 girls (mean age, 7.2 years) were studied. Ninety-six percent were attributed to HBV genotypes A (32.5%) or D (63.5%). The remaining were classified as genotypes B, C, E and F. There was no significant difference in both alanine aminotransferase levels and histological findings among different genotypes. However, there was a clear association between very high HBV DNA levels and individuals with genotype D (P = 0.006). Mean time follow-up of 3.6 years showed later anti-HBe seroconversion in patients with genotype D than in those with genotype A (58% vs 37%).

CONCLUSIONS

Compared with children with genotype A, children with genotype D showed a significantly higher viral load. Inasmuch as a relationship exists between viral load and response to treatment in children infected through vertical transmission, children with genotype D have to be carefully monitored. Long-term studies are needed to determine whether these patients are at risk of a poorer outcome.

Impact of hepatitis B vaccination on hepatitis B disease and nucleic acid testing in high-prevalence populations

Hepatitis B virus (HBV) infection is highly prevalent in Asia, Africa, southern Europe and Latin America, HBV vaccination has effectively reduced the acute and chronic infection rates as well as related complications in the vaccinated children. The incidence of hepatocellular carcinoma in children has been reduced to approximately 25% of the incidence before the vaccination program, and fulminant hepatitis in children has also been reduced after universal hepatitis B vaccination. HBV DNA sero-positive rate was 98-100% in HBsAg positive vaccinated children, while the positive rate was only 11-20% in those vaccinees with a negative HBsAg but positive anti-HBc reaction. Hepatitis B surface gene mutants in HBV DNA positive children increased gradually from 7.8% before the vaccination program, to 19.6%, 28.1% and 23.1% at 5, 10 and 15 years after the vaccination program. Long-term follow-up of vaccinated children has confirmed that universal HBV vaccination in infancy has produced adequate protection up to 14 years of age. The annual decay rate of hepatitis B surface antibody (anti-HBs) was 10.2% in children who did not receive a booster dose. The new HBV infection rate was not different between those who did and those who did not receive a booster dose of HBV vaccine. During a follow-up period of seven years for 1200 vaccinated 7-year-old children in Taiwan, the mean annual hepatitis B core antibody sero-conversion rate was 0.2%. All were negative for HBV DNA. No new chronic HBV infections developed. A booster dose of HBV vaccine is not recommended in children under 15 years of age. Systematic HBV DNA screening of a large population such as blood donors may be instrumental in following the long-term effect of the universal vaccination program on the incidence of silent HBV infection and vaccine escape mutants.

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.

Lamivudine treatment in maternally transmitted chronic hepatitis B virus infection patients

BACKGROUND

Lamivudine treatment in chronic carriers who acquired hepatitis B virus through maternal transmission were investigated.

METHODS

A total of 29 subjects (Male:Female, 24:5; mean age, 14.7 +/- 5.6 years) who were hepatitis B e antigen (HBeAg) seropositive for >6 months, alanine aminotransferase (ALT) was >1.3 times of upper limit of normal value, and receiving a 52 week-long treatment, received open-label lamivudine (3 mg/kg per day, maximum 100 mg/day). Another 29 subjects matched for gender, age, liver function, and HBeAg status followed up before the introduction of lamivudine served as the control group. The control group did not receive any treatment and were evaluated at week 52 after the onset of abnormal ALT. Mothers of all study subjects were hepatitis B surface antigen (HBsAg) carriers. A successful treatment response at week 52 was defined as: (i) undetectable hepatitis B virus DNA by real time polymerase chain reaction; (ii) normal ALT; and (iii) HBeAg/anti-HBe seroconversion. Lamivudine-resistant YMDD mutants were checked at week 52.

RESULTS

The lamivudine group did not reach a better successful treatment response rate than the control group (17 vs 10%, P = 0.44), except in patients with a baseline ALT >5 times of the upper limit of normal value. YMDD mutants developed in 34% of patients in the lamivudine group.

CONCLUSION

Lamivudine treatment is effective for maternally transmitted subjects with high ALT.

Clinical relevance of hepatitis B virus genotype in children with chronic infection and hepatocellular carcinoma

BACKGROUND & AIMS

The aim of this study was to investigate the influence of hepatitis B virus (HBV) genotypes on the clinical outcome of chronic childhood HBV infection and hepatocellular carcinoma (HCC).

METHODS

A total of 460 HBV carrier children were followed-up for 15 years and 26 children with HBV-related HCC were recruited. HBV genotyping was examined at enrollment and the latest follow-up of these carrier children and at diagnosis in HCC children. Viral load was checked at enrollment for the carrier children. These carriers were grouped based on their initial hepatitis B e antigen (HBeAg) and antibody to hepatitis B e antigen (anti-HBe) status. The HBeAg positive (+) group was divided further into an HBeAg(+/+) group and HBeAg(+/-) group, depending on whether spontaneous HBeAg seroconversion occurred during the follow-up period.

RESULTS

Genotype B constituted 73%, 86%, and 76% in the HBeAg(+/+), HBeAg(+/-), and anti-HBe(+) groups, respectively. Genotype C was found in 27%, 8%, and 6% in the HBeAg(+/+), HBeAg(+/-), and anti-HBe(+) group, respectively. Genotype C carriers were more prevalent in the HBeAg(+/+) group than the other 2 groups (P = .01), and had a delayed HBeAg seroconversion compared with the genotype B carriers (P < .001). Changes of genotype during the follow-up period were rare (2.8%). In those with HCC, genotype B was also the major type (74%). There was no difference in the baseline viral load between genotypes B and C.

CONCLUSIONS

Although HBV genotype B dominates in children with chronic HBV infection and HCC in Taiwan, genotype C delays HBeAg seroconversion in pediatric chronic HBV infection.

Longitudinal study on mutation profiles of core promoter and precore regions of the hepatitis B virus genome in children

Precore nucleotide 1896 and core promoter mutations may account for hepatitis B e antigen (HBeAg) seroconversion in chronic hepatitis B virus (HBV) infection, yet the mutational profiles of the core promoter are largely unknown in children. An age-matched, case-control study enrolled 110 chronic HBV-infected children, including 55 HBeAg seroconverters and 55 nonseroconverters. Precore and core promoter genes of HBV were sequenced and the serum viral genomes were genotyped from three serial serum samples of the seroconverters and from one serum sample of the nonseroconverters. Higher frequency of A1775G and G1799C mutation rates and lower frequency of A1752G mutation rate were found in the seroconverters. Precore 1896 mutation appeared more in seroconverters than in nonseroconverters (45.5% versus 10.9%; p < 0.001). 1762 + 1764 mutation rates were not different between the seroconverters (9.1%) and the nonseroconverters (5.5%). Genotype B was the major type. Genotype C was associated with core promoter 1762 + 1764 mutations in the seroconverter group (p = 0.023). The conclusions of this study include the following: 1) mutations of core promoter at nucleotide position 1752, 1775, and 1799 have significant correlations with HBeAg seroconversion; 2) core promoter 1762 + 1764 mutations play a minimal role in HBeAg seroconversion; 3) precore 1896 mutant accounted for half of childhood HBeAg seroconversion; 4) genotype C is associated with 1762 + 1764 mutations during the process of HBeAg seroconversion.

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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.

Response to lamivudine treatment in children with chronic hepatitis B virus infection

Despite the recent approval of lamivudine for the treatment of children with chronic hepatitis B virus (HBV) infection, there is insufficient information on the kinetics of HBV clearance and the factors that predict a favorable treatment response to lamivudine in this population. In a small retrospective study of 16 HBV-infected children treated with lamivudine, we examined changes in virus load and other factors associated with hepatitis B e antigen (HBeAg) clearance. High pretherapy alanine aminotransferase level, low serum HBV DNA load, and age at the start of treatment were independently associated with HBeAg clearance. HBeAg clearance was also associated with the achievement of specific levels of virus suppression, and failure to achieve those levels was associated with the development of lamivudine resistance. Additional studies are necessary to provide better indications and guidelines for the treatment of children with chronic HBV infection.

Histologic activity of childhood chronic hepatitis B related to viremia levels, genotypes, mutations, and epidemiologic factors

BACKGROUND

Despite high viral load, children with chronic hepatitis B virus (HBV) infection may lack significant biochemical signs of liver dysfunction. Failure to develop abnormal liver chemistriesis is probably due to immunologic hyporeactivity. Despite the absence of biochemical abnormalities in these patients, there is still a risk for long-term complications. The pathogenic importance of viral load and genetic variability is less well studied in children than in adults.

METHODS

We evaluated viremia levels, genotypes, and mutations related to histologic evidence of liver damage in 71 HBV carriers, aged 2 to 18 years, all of non-Swedish origin.

RESULTS

None of the of 22 children who were hepatitis B e antigen (HBeAg) negative had severe liver disease or had HBV DNA levels greater than 10 copies/mL (mean 10 ); 3 (14%) of them had increased alanine aminotransferase (ALT). The 49 HBeAg-positive children had a mean HBV DNA level of 10 copies/mL, and increased ALT was seen in 28 (55%). Core promoter mutations (at nt 1764) or precore mutations (at codon 1, 2, or 28) were rare; they were seen in four and one HBeAg-positive children, and in four and nine HBeAg-negative children, respectively, without association to liver damage. C-1858 was associated with more liver inflammation. Genotype did not significantly influence liver damage. Children with horizontal transmission had a faster rate of seroconversion and more inflammation of the liver.

CONCLUSIONS

Severe HBeAg-negative hepatitis with high HBV DNA levels and mutations in the core promoter or precore regions seems to be less common in children than in adults. C-1858 strains may be more pathogenic, but this requires further study. Epidemiologic factors influence the course of infection.

Structural and functional heterogeneity of naturally occurring hepatitis B virus variants

Most organisms have developed sophisticated machineries to preserve their genomic integrity. On the contrary hepatitis B virus (HBV), like a lot of other viruses can undergo rapid and drastic sequence changes, especially if the virus has to cope with natural or therapy induced antiviral mechanisms in the host. Here, we try to summarize possible implications for the molecular pathogenesis of HBV based on the extensive research on the genetic variants of HBV.

Efficacy of a mass hepatitis B immunization program after switching to recombinant hepatitis B vaccine: a population-based study in Taiwan

To study the efficacy of immunization against hepatitis B after plasma-derived vaccine was replaced by recombinant vaccine, 2-year-old Taiwanese children were recruited by stratification random sampling and tested for hepatitis B markers. They were grouped according to maternal infectivity and children's immunization status. Of 2010 children, 2.5% had hepatitis B surface antigen (HBsAg), 94.1% had its antibody (anti-HBs), 6.8% had core antibody, and 3.3% were seronegative. Children of highly infectious mothers immunized with hepatitis B immunoglobulin and vaccine on schedule had a lower HBsAg-positive rate and a higher anti-HBs-positive rate than those with vaccine only and off-schedule. The efficacy of the Taiwanese mass hepatitis B immunization was maintained after switching to recombinant hepatitis B vaccine.

Natural history of hepatitis B virus infection in children

Hepatitis B virus (HBV) infection during childhood can cause acute, fulminant or chronic hepatitis, liver cirrhosis, and liver cancer. Approximately 90% of the infants of hepatitis B e antigen (HBeAg) seropositive mothers become hepatitis B surface antigen (HBsAg) carriers. Children chronically infected are mostly asymptomatic. Although liver damage is usually mild during childhood, severe liver disease, including cirrhosis and hepatocellular carcinoma, may develop insidiously for 2-7 years. Spontaneous HBeAg seroconversion occurs gradually as the age of the child increases. Viral replication is reduced during this process, which is usually preceded by an elevation of aminotransferases. In a long-term follow-up study, the annual HBeAg seroconversion rate was 4-5% in children older than 3 years of age and less than 2% in children under 3 years. The annual seroconversion rate of HBsAg was very low (0.56%). Age at infection, maternal HBsAg and HBeAg status, host immune status, and possibly the HBV strain are the main factors determining the course of HBV infection in children.

Cytokine release of peripheral blood mononuclear cells in children with chronic hepatitis B virus infection

BACKGROUND

Immune response to hepatitis B virus (HBV) antigens or mitogens in Asian children with chronic HBV infection who are mainly perinatally infected has not been studied in connection with the production of various cytokines, although these patients are considered to be less responsive to antiviral therapy.

METHODS

The production of the cytokines interferon (IFN)-gamma, lymphotoxin, interleukin (IL)-4, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta by peripheral blood mononuclear cells (PBMCs) was studied in 17 hepatitis B surface antigen (HBsAg) carrier children with raised alanine transferase levels (group 1), 17 HBsAg carrier children with normal alanine transferase levels (group 2), and 20 healthy noncarrier control subjects (group 3).

RESULTS

Hepatitis B core antigen (HBcAg)-stimulated IFN-gamma production was significantly higher in group 1 than in groups 2 and 3, serum HBeAg cleared within 1 year in five of eight children in group 1 with stimulation indexes higher than 3, and HBcAg-induced IL-4 secretion was minimal in all groups. Interferon-gamma produced by PBMCs stimulated by purified HBsAg did not differ among the three groups. Higher lymphotoxin production by PBMCs stimulated by HBcAg was also noted in groups 1 and 2 than in group 3. Lipopolysaccharide (LPS)-stimulated TNF-alpha production by PBMCs was significantly higher in group 1 than in group 2. There was no association between HBeAg-anti-HBe status and production of various cytokines. No differences were seen in the profile of cytokines induced by HBV antigens or LPS in children of carrier mothers compared with children of HBsAg-negative mothers.

CONCLUSION

Increased IFN-gamma production resulting from HBcAg-specific T-helper lymphocyte type 1 response, and increased TNF-alpha production may contribute to cell-mediated antiviral immune response in children with chronic hepatitis B. In HBV carrier children, the ability to produce the studied cytokines is related to whether an endogenous immune attempt to eliminate HBV infection emerges in the patients but is not related to the different modes of acquisition of HBV infection.

Clinical and histological outcome after hepatitis B e antigen to antibody seroconversion in children with chronic hepatitis B

Data regarding the outcome of children with chronic hepatitis B after seroconversion are scarce. We describe the long-term evolution of these patients. One hundred and three children with antibody against hepatitis B e antigen and normal alanine aminotransferase (ALT) levels were followed for 0.6 to 12.5 years (mean, 6.3 years). Paired liver biopsies (before and after seroconversion) were available in 83 cases. Final biopsies were obtained 0.5 to 12.5 years (mean, 4.5 years) after seroconversion. ALT levels remained normal in most of the children (79%) throughout the follow-up. All children, except five who lost hepatitis B surface antigen, had serum viral DNA detected by polymerase chain reaction. When comparing baseline and final liver biopsies, a significant improvement (P <.001) was found in the histological activity index and in the necrosis, cytolysis, inflammation, and fibrosis scores. The histological diagnosis improvement in the final biopsy was significantly related (P <.001) to the time from seroconversion to the biopsy performance. All children had viral DNA on their final liver biopsy. In summary, seroconversion and ALT normalization are quite stable findings in children, and no differences in the long-term outcome between treated and untreated children were found. In light of the histological outcome, it seems unnecessary to perform a follow-up liver biopsy in these cases.

Chronic hepatitis virus infection in children

Hepatitis B and C viruses (HBV and HCV) are the two main hepatitis viruses causing chronic liver diseases in children. In hyperendemic areas, nearly half of the primary infection in chronic HBV carriers occurs during the perinatal period through the transmission from hepatitis B e antigen (HBeAg)-positive mothers. The other half are from horizontal transmission mainly through intrafamilial spread or injection using unsterilized needles. During the natural course of chronic HBV infection, spontaneous HBeAg/anti-HBe seroconversion occurs very rarely (2% annually) before 3 years of age. After 3 years of age, the HBeAg seroconversion rate increases gradually to 5% per year. Those with mothers who are hepatitis B carriers tend to clear HBeAg slower than those whose mothers are non-carriers. Transplacental HBeAg may cause T cell tolerance in infected children. Universal HBV immunization programmes have been effective in reducing the hepatitis B carrier rate more than 10-fold, and the incidence of hepatocellular carcinoma in children has also been decreased significantly. Hepatitis C virus infection occurs mainly in high-risk children, such as those who received blood products (blood diseases, malignancies, post-open heart surgery etc.), children of HCV-infected mothers, and in hyperendemic areas, from injection using unsterile needles. Mother-to-infant transmission occurs on average in 5% of infants of viraemic mothers. The maternal HCV-RNA titre is the most important factor determining the infectivity. Chronicity developed in 60-80% of HCV-infected children. Although transient or persistent elevation of aminotransferases occurs frequently in chronically HCV-infected children, liver histology showed minimal or mild changes only. The most prevalent genotype of HCV in children is Ib. Screening of the blood products for HCV antibody has markedly reduced the rate of HCV infection in children at risk. However, vaccine development is needed to prevent mother-to-infant transmission and other routes of infections.

Hepatitis B vaccination in preterm infants

AIM

To investigate the immunogenicity and safety of existing recommendations for hepatitis B vaccination in preterm infants.

METHODS

Recombinant hepatitis B vaccine (H-B-VAX II, 5 micrograms per dose) was given to 85 preterm infants divided into two groups, using two different schedules. Forty four group A infants with birthweights of < 2000 g received three doses at 1, 2, and 7 months of age. Forty one group B infants with birthweights of > or = 2000 g received three doses at 0, 1, and 6 months of age.

RESULTS

After vaccination, 42 infants from group A (95%) and 37 infants from group B (90%) developed protective levels of antibody. The final seropositive rate and the geometric mean concentration of hepatitis B surface antibody between the two groups were not significantly different. The immune response of preterm infants to hepatitis B vaccines was similar to that of term infants in a previous study.

CONCLUSIONS

Preterm infants can be given hepatitis B vaccines using one of the above two different schedules, at a cutoff birthweight of 2000 g.

A follow-up study of combined vaccination with plasma-derived and recombinant hepatitis B vaccines in infants

This study was aimed to evaluate the efficacy and immunogenicity of combined hepatitis B vaccination with plasma-derived vaccine (PDV) and recombinant vaccine (RV). A total of 329 infants was recruited, including 224 high-risk infants born to hepatitis B e antigen-positive mothers and 105 low-risk infants born to hepatitis B e antigen-negative mothers. The high-risk infants received four doses of hepatitis B vaccine at 0, 1, 2 and 12 months of age with five different schedules. Group A1 and A2 infants were vaccinated with PDV as the first dose and RV (SB vaccine for group A1, MSD vaccine for group A2) as the remaining three doses. Group B1 and group B2 infants were vaccinated with PDV as the first two doses and RV (SB vaccine for group B1, MSD vaccine for group B2) as the remaining two doses. Group C infants received four doses of PDV. Low-risk infants were vaccinated with PDV at birth, and RV at 1 and 6 months of age (group D1, using SB vaccine; group D2, using MSD vaccine). At completion of vaccination schedules, 20 of 224 high-risk infants (9%) were positive for hepatitis B surface antigen. The overall protective efficacy was 90%. Hepatitis B surface antibody (anti-HBs)-positive rate ranged between 94 and 100% among the remaining infants. The protective efficacy and immunogenicity were similar among groups except that the mean level of anti-HBs in group C, D1 and D2 infants tended to be lower than that of the other four groups. To ensure an optimal immune response, four doses of vaccine are recommended in high-risk infants when two types of vaccine are to be used in combination.

Chronic viral hepatitis

Among hepatitis A to E viruses, hepatitis B, C, and D viruses can cause chronic hepatitis, in both children and adults. Hepatitis B virus (HBV) infection is the most prevalent and important one. Perinatal transmission accounts for about 40-45% of chronic HBV infection in hyperendemic areas. Horizontal transmission through intramuscular injection using non-sterile needles and intrafamilial spread accounts for the other half of carriers. During the natural course of HBV infection, the host gradually clears HBV and hepatitis B e antigen (HBeAg), liver damage and elevation of aminotransferases occur during the process of HBV clearance. The most effective way to eliminate HBV infection is immunoprophylaxis starting since birth. It can prevent both HBV and hepatitis D virus (HDV) infections. Hepatitis C virus (HCV) infection in children occurs mainly in high risk children, such as those who received blood product or injection using non-sterile needles, or infants of HCV viremic mothers, etc. Screening of blood product reduced markedly the prevalence of post-transfusion HCV infection, but the prevention of sporadic cases requires HCV vaccination which is still under investigation.

Long-term efficacy of recombinant hepatitis B vaccine and risk of natural infection in infants born to mothers with hepatitis B e antigen

To evaluate the long-term protection afforded by the vaccine, recombinant hepatitis B (HB) vaccine was given to 171 infants born to hepatitis B e antigen-positive carrier mothers. Group A (53 infants) and group B (57 infants) received four doses of HB vaccine at birth and at 1, 2, and 12 months of age, with a dose of 20 micrograms in group A and 10 micrograms in group B. Group C (61 infants) received three 20 micrograms doses of HB vaccine at birth and at 1 and 6 months of age. These children were followed up annually up to 5 years of age. Six children (4%) became HB carriers before 1 year of age, and the carrier state persisted to the end of follow-up. The overall seropositive rate of HB surface antibody (anti-HBs) dropped from 99% at 1 year of age to 83% at 5 years of age. Among 548 serum pairs taken at 1-year intervals from children negative for HB surface antigen (HBsAg), a fourfold rise of anti-HBs titer was noted in 58 (11%) and a 10-fold rise of anti-HBs was noted in 17 (3%). Maternal HB core antibody disappeared in most children (151/152, 99%) before 2 years of age. Natural infections, as judged by persistence or reappearance of HB core antibody, occurred in 19 of 163 (12%) HBsAg-negative children. None of these episodes was associated with HBsAg positivity. We conclude that the long-term protection afforded by recombinant HB vaccine is satisfactory and that a further booster dose before 5 years of age is not necessary.

Long-term follow-up of hepatitis B virus carrier infants

One hundred twenty-two hepatitis B surface antigen (HBsAg) carrier infants were followed-up for 8-10 years. One hundred eleven had antibody to hepatitis B core antigen (anti-HBc; 83 had been vaccinated) and the remaining 11 were without anti-HBc (7 had been vaccinated). During the follow-up period, 29 (26.1%) carrier infants with anti-HBc had one or more episodes of alanine aminotransferase (ALT) elevation and up to 32.8% (21/64) of the carriers in this group lost their hepatitis B e antigen (HBeAg) before the age of 10. In addition, 2 (1.8%) carriers lost their HBsAg at the age of 3 and 8, respectively. No significant symptom or sign was noted during HBeAg seroconversion. In contrast, all the carrier infants without anti-HBc were still positive for both HBeAg and hepatitis B virus (HBV) DNA and none displayed abnormal ALT levels or any symptom related to liver disease. One became anti-HBc positive at the age of 9, and 5 other carriers had inconsistent borderline or weakly positive titers of anti-HBc. The episodes of ALT elevation and the prevalence of HBeAg seroconversion were not significantly different between immunized carrier infants. In conclusion, HBeAg seroconversion may occur in about one third of the anti-HBc-positive carrier infants during the first decade. On the other hand, the anti-HBc-negative HBsAg carrier infants' immune incompetence to the HBV antigens could persist for more than 10 years. Hepatitis B immunization did not have significant effect on the clinical course in carriers.

Coinfection study of precore mutant and wild-type hepatitis B-like virus in ducklings

The precore mutant hepatitis B virus often emerges from a mixed infection with combined wild-type and precore mutant viruses. Nevertheless, the precore mutant does not seem to be an evolutionarily favored strain. To investigate the interaction between wild-type and precore mutant hepadnaviruses in an animal model of perinatal transmission, we used an e antigen-defective mutant duck hepatitis B virus with mutations inside the stem-loop structure of precore messenger RNA for this coinfection study. Thirty 1-day-old ducklings were infected with wild-type duck hepatitis B virus, precore mutant virus or both viruses. The amounts of viremia and the distribution of viruses were analyzed by spot hybridization, polymerase chain reaction, restriction fragment length polymorphism, cloning and sequencing. We found that all the ducklings became chronic carriers of duck hepatitis B virus. The precore mutant replicate was less active than wild-type duck hepatitis B virus, and it could be overgrown by wild-type virus during the course of coinfection. These results demonstrated that wild-type duck hepatitis B virus might become the predominant species in a situation similar to the perinatal cotransmission in human beings. This might at least in part explain why the prototype virus could prevail for years.

Natural history of chronic hepatitis B virus infection: new light on an old story

Chronic hepatitis B virus (HBV) infection is one of the most common persistent virus infection in man. It causes significant morbidity and mortality, and therefore is important. Extensive studies on clinicopathologic studies and long-term follow up on hepatitis B surface antigen (HBsAg) carriers have largely disclosed the natural history of chronic HBV infection. The infection easily becomes chronic when contracted in early infancy. As high as 90% of babies born to HBV carrier mothers will also become HBsAg carriers. Once chronic infection is established, it is refractory, and HBsAg carriage usually persists for life. However, the chronic infection is not monotonous, it actually evolves from an HBV replicative phase to a non-replicative phase. The host responds differently and with more complexity in different phases. The virus-host interactions, divided into three phases, virus tolerance, virus clearance and residual HBV integrated phases, result in a heterogeneous variety of hepatic lesions. The first two phases occur when HBV is actively replicating, and the last corresponds to the non-replicative phase. The high HBV level (and hence HBV gene products) renders the host's immune system tolerant to the virus, and the infected host does not exert an effort to get rid of the virus. At this stage, the liver is nearly normal, and the host is asymptomatic. However, later in the replicative phase, the HBV replication begins to wane, and the immune tolerance is no longer maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical significance of low or negative titer of antibody to hepatitis B core antigen during the course of chronic hepatitis B virus infection in adolescents

Antibody to hepatitis B core antigen (anti-HBc) was measured by radioimmunoassay in 127 asymptomatic hepatitis B surface antigen (HBsAg) carriers (ASC; mean age 19) who had normal serum alanine aminotransferase (ALT) levels and 16 patients with chronic hepatitis B (CH; 19). All 16 CH patients, who were positive for hepatitis B e antigen (HBeAg) and 5 ASC cases who were negative for both HBeAg and its antibody (anti-HBe), had high anti-HBc titers. Anti-HBc titers in 27 (56.3%) of the 48 HBeAg-positive ASC and 18 (24.3%) of the 74 anti-HBe-positive ASC were relatively low. Two of the ASC were HBeAg-positive/anti-HBc-negative. In a follow-up study of the 19 HBeAg-positive ASC with low or negative anti-HBc titers, 5 had abnormal serum ALT levels and increased anti-HBc titers. In contrast, in the other 14 of these subjects, serum ALT levels remained normal and the low anti-HBc titers remained unchanged and/or decreased. The serological profile of HBsAg-positive/low or negative anti-HBc titer and increased anti-HBc titer with abnormal serum ALT levels are not necessarily exceptional in HBeAg-positive adolescent ASC. It is suggested that anti-HBc is associated with the liver damage that occurs before adolescence in chronic hepatitis B virus infection.

Absence or delayed appearance of hepatitis B core antibody in chronic hepatitis B surface antigen carrier children

An absence of the hepatitis B core antibody (anti-HBc) in hepatitis B surface antigen (HBsAg) carrier children has been reported before, but whether anti-HBc will ultimately appear is unknown. In a group of 420 HBsAg carrier children who were followed longitudinally, 10 (2.4%) had an absence or delayed appearance of serum anti-HBc. These 10 children were persistently seropositive for HBsAg, hepatitis B e-antigen, and hepatitis B virus DNA (HBV-DNA). Anti-HBc never appeared in 4, one of whom was a case of hepatitis B vaccine failure and became an HBsAg carrier. Three of the 4 were born to HBsAg carrier mothers. Liver biopsy in one revealed non-specific reactive hepatitis (NSRH). All 4 were asymptomatic during follow-up. Mothers of the other 6 children who had delayed appearance of anti-HBc were also HBsAg carriers. The children seroconverted to anti-HBc positivity between 2 and 8 years of age, and the titer of serum anti-HBc at the first appearance varied. There were no significant changes in liver function tests, HBV-DNA levels, or associated symptoms and signs before and after seroconversion. Liver biopsies were performed before anti-HBc seroconversion in 2 children and showed NSRH. All 10 children had a moderate to high replication of HBV as shown by the high titer of HBsAg and HBV-DNA. The absence of anti-HBc occurred almost exclusively in children who were infected perinatally.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon alfa-2b therapy in children with chronic hepatitis B

Twenty nine children (mean age 8.3 years, 18 boys, 11 girls) who had biopsy proved chronic hepatitis B virus infection (HBV) with active viral replication were given a 16 week course of interferon alfa-2b treatment (9 million units (MU)/m2, thrice weekly). Fourteen children (48%) showed persistent loss of HBV-DNA 8 months after the end of treatment; 11 (38%) lost hepatitis B e antigen (HBeAg), and two (7%) hepatitis B surface antigen (HBsAg). Alanine aminotransferase activities returned to normal in 12 children. Those who responded had significantly higher initial transaminase activities than those who did not (p < 0.01) but similar serum HBV-DNA. Results were compared with the natural evolution of the disease in a group of 25 children (mean age 8.3 years) with identical initial mean serum HBV-DNA values, followed up during the same period. Two of these (8%) lost HBeAg and one (4%) HBsAg. The 23 remaining control subjects had no decrease in serum HBV-DNA or in transaminase activities compared with values 1 year earlier. It is concluded that treatment with interferon alfa-2b in children may lead to inhibition of HBV replication similar to that described in adults, and may thus shorten disease evolution. Further studies are necessary to establish the best protocols and to identify those patients who are the most likely to respond to treatment.

Spontaneous loss of HBsAg in children with chronic hepatitis B virus infection

Spontaneous loss of HBsAg is infrequent in adult HBV carriers. Little is known about this serological change in children. In a prospective study of 420 hepatitis B virus-carrier children who were observed for 1 to 12 yr (mean = 4.3 yr), spontaneous loss of HBsAg occurred in 10 patients, with an average incidence of 0.6%/yr. The HBsAg clearance rate was significantly higher in children who had anti-HBe; children who were at an older age on entry; children whose mothers were HBsAg-; or children with severe liver histological changes detected while they were HBeAg+. Children who seroconverted from HBeAg to anti-HBe before the age of 6 or who had a peak serum ALT level above 100 IU/L were more likely to clear HBsAg. In all 10 patients who became HBsAg-, serum hepatitis B virus DNA became undetectable by both spot hybridization and the polymerase chain reaction, suggesting a complete clearance of the virus from serum. After the loss of HBsAg, the anti-HBs levels were higher in the children born to carrier mothers than in those born to noncarrier mothers. These findings suggest that chronic hepatitis B virus-carrier children rarely lose HBsAg, especially if they have been infected during the perinatal period and have mild histological changes. The poor humoral immune response to HBsAg may be a contributing factor in the establishment of carrier status during horizontal infection but may not be primarily involved in the establishment of carrier status during perinatal infection.

Acute exacerbations of chronic type B hepatitis are accompanied by increased T cell responses to hepatitis B core and e antigens. Implications for hepatitis B e antigen seroconversion

T cell proliferative responses to hepatitis B virus-encoded envelope antigen (S + preS2 + preS1), recombinant core antigen (HBcAg), and natural hepatitis B e antigen (HBeAg) were examined in 22 HBeAg-positive patients with chronic type B hepatitis and 17 healthy hepatitis B surface antigen (HBsAg) carriers. The results showed that HBeAg-positive patients had (a) higher levels of T cell responses to HBcAg/HBeAg than those of healthy HBsAg carriers (P less than 0.001 and P less than 0.01, respectively); (b) a further increase in these T cell responses during acute exacerbations (P less than 0.05 and P less than 0.05, respectively); (c) subsidence in the T cell responses to HBcAg/HBeAg after recovery from acute exacerbations and HBeAg seroconversion, whereas the responses would persist at high levels if the patients did not enter a clinical remission; and (d) low levels of T cell responses to S + preS2 + preS1 either before or after HBeAg seroconversion. The appearance of increasing T cell responses to HBcAg/HBeAg usually occurred in the early phase of acute exacerbations. These findings imply that HBcAg/HBeAg-specific T cells play an important role in the exacerbations of chronic hepatitis B and in HBeAg seroconversion. HBcAg/HBeAg-specific precursor T cell frequencies were serially studied in selected cases by limiting dilution assay. Elevation (two- to fourfold) of HBcAg/HBeAg-specific precursor T cell frequencies contributed to the increase of HBcAg/HBeAg-specific T cell proliferation during acute exacerbations.