Analysis of hepatitis B precore region in serum and liver of chronic hepatitis B virus carriers

Treatment options for chronic hepatitis B and C infection in children

There has been a dramatic increase in treatment options for both chronic hepatitis B (CHB) and chronic hepatitis C (CHC) infection in adults over the past 5-10 years, resulting in standardized regimes for initial treatment, relapsers and even infection in the setting of recurrence post-liver transplantation. These regimes have resulted in the halting of the disease progression, reduction in the risk of hepatocellular carcinoma and removal of these infections as a contraindication for liver transplantation. However, treatment in children must be considered carefully in the context of the natural history of these infections and host factors, particularly the immunological mileu, which may affect response to therapy. The as yet unknown long-term effects of medications must also be balanced with the probability of significant life-long morbidity or mortality from chronic hepatitis and its complications. Furthermore, the development of drug resistance, particularly in the case of CHB, has significant implications for the pediatric patient who may exhaust effective therapeutic options at a relatively young age. For these reasons, initiation of therapy must be based on sound criteria. Based on the current data, we recommend that therapy should be offered to children with CHB who have an elevation in alanine aminotransferase (>2-3 x upper limit of normal) for more than 6 months. Therapy with interferon-alpha should be offered in the majority of cases with the aim of immune clearance as measured by early antigen seroconversion. By contrast, treatment indication for CHC in children remains controversial. If used, combination therapy with pegylated interferon and ribavirin is likely to produce the highest rates of sustained viral response.

Hepatitis B virus genotypes and precore/core-promoter mutations in Tunisian patients with chronic hepatitis B virus infection

OBJECTIVE

The aim of this study was to determine the frequency of genotype and precore/core-promoter mutations in chronic hepatitis B virus (HBV) infected individuals in Tunisia.

METHODS

We studied 164 Tunisian patients (38 HBeAg-positive and 126 HBeAg-negative) with chronic HBV infection. Genotypes and precore/core-promoter mutations were studied using Inno-LiPA and Multiplex-PCR and PCR-RFLP methodology.

RESULTS

Alanine aminotransferase (ALT) levels were higher in HBeAg-positive compared with HBeAg-negative patients (p<0.05). Patients with HBeAg-positive chronic hepatitis B were younger than HBeAg-negative chronic hepatitis B patients. The 164 genotypes were distributed as follows: 1 genotype A (0.6%), 1 genotype B (0.6%), 3 genotype C (1.82%), 139 genotype D (84.75%), and 20 mixed genotypes (12.2%). In the precore region (41.5%) of the patients had exclusively PC mutant and (50.9%) had a mixture of wild-type and variant sequences. PC variant was more commonly found in HBeAg-negative patients than in HBeAg-positive patients (94.5% vs. 87.8%), respectively. The mutations in the core promoter were more common in HBeAg-negative patients (65.4%) than in HbeAg-positive patients (18.2%). These results indicate that genotype D is predominant in Tunisia. Precore mutation occurred invariably among HBeAg-positive and HBeAg-negative patients, whereas core-promoter mutations were more frequently found in HBeAg-negative patients.

CONCLUSION

Analysis of these mutants may prove useful for clinical evaluation and choice of therapy.

Hepatitis B: epidemiological, immunological, and serological considerations emphasizing mutation

The global prevalence of hepatitis B virus is estimated to be 350 million chronic carriers, varying widely from low (<2%, as in Western Europe, North America, New Zealand, Australia, and Japan) to high (>8% as in Africa, Southeast Asia, and China). The overall prevalence in Brazil is about 8%. There are currently 7 genotypic variations, from A to G, and also 4 main surface antigen subtypes: adw, ayw, adr, and ayr. There has been great interest in identifying the geographic distribution and prognosis associated with the various genotypes and subtypes. Although the serologic test is highly sensitive and specific, it does not detect cases of mutant hepatitis B, which is increasingly common worldwide due to resistance and vaccine escape, antiviral therapy, and immunosuppression, among other causes. Alterations in surface, polymerase, X region, core, and precore genes have been described. The main mutations occur in surface and in core/precore genes, also known as occult hepatitis, since its serologic markers of active infection (HBsAg) and viral replication (HBeAg) can be negative. Thus, mutation should be suspected when serologic tests to hepatitis B show control of immunity or replication coincident with worsened clinical status and exclusion of other causes of hepatitis.

World-wide epidemiology of HBeAg-negative chronic hepatitis B and associated precore and core promoter variants

Hepatitis B is a serious disease that is endemic in many parts of the world. A significant proportion of patients with chronic hepatitis B (CHB) are infected with a variant form of the hepatitis B virus (HBV) which decreases or abolishes the production of hepatitis B e-antigen (HBeAg). The purpose of this literature review is to describe the epidemiology of HBeAg-negative CHB (e-CHB) worldwide. A literature search was conducted to identify studies pertaining to e-CHB and underlying variants (precore and core promoter). Fifty studies were included in our analysis. The median prevalence of e-CHB among patients with chronic HBV infection was 33% in the Mediterranean, 15% in Asia Pacific, and 14% in the USA and Northern Europe. The pre core stop codon variant was detected in a median of 60% (range 0-100%) of HBeAg-negative patients overall, 92% in the Mediterranean, 50% in Asia Pacific and 24% in the USA and Northern Europe. There were very few data on the prevalence of core promoter variants outside Asia where the median prevalence among HBeAg-negative patients was 77%. This literature review revealed that e-CHB is more common than previously suspected and that it is present worldwide with marked variations in the prevalence of associated HBV variants across different geographical regions. Additional research using population based samples of adequate size based on a consensus definition of e-CHB and using standardized HBV DNA assays is needed to better estimate the true prevalence of e-CHB and its associated HBV variants.

TT virus detection in oral lichen planus lesions

Epidemiological studies have demonstrated a correlation between oral lichen planus and different liver diseases. The new virus termed TT virus (TTV) is highly prevalent in patients with chronic hepatitis of different etiology and it may be speculated that TT virus may be involved in the pathogenesis of oral lichen planus. This study examined the presence of TT virus DNA in serum by PCR and in oral mucosa biopsies by in situ hybridization from 20 patients with oral lichen planus (13 with chronic hepatitis and seven without liver disease). Serum and oral mucosa biopsies from six patients all with chronic hepatitis with leukoplakia were also studied as controls. TT virus DNA was positive in the serum of 17/20 (85%) of the patients with oral lichen planus and in all the controls. TT virus DNA hybridization signals were detected in mucosa biopsies from all the patients with TT virus DNA in serum but in none of the three cases without this marker. The percentage of positive cells ranged from 1.6-80%. No differences were found in the percentage of positive cells between TT virus positive patients with and without oral lichen planus and there was no relationship between the number of positive cells and the intensity of the inflammatory infiltrate. In conclusion, TT virus infects oral epithelial cells but the results do not support a role for TT virus in causing oral lichen planus.

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.

Hepatitis B virus precore mutants in serum and liver of Southern African Blacks with hepatocellular carcinoma

BACKGROUND/AIM

The aim of this study was to sequence the precore region of HBV isolated from serum and tumorous and non-tumorous liver tissue from patients with hepatocellular carcinoma to identify mutations that might play a role in malignant transformation.

METHODS

HBV DNA was extracted from 62 sera, 14 tumorous and 12 non-tumorous liver tissue samples of patients with hepatocellular carcinoma, amplified by the polymerase chain reaction and sequenced directly.

RESULTS

Thirty-nine patients were HBeAg-negative and 23 HBeAg-positive. Missense mutations were present predominantly in HBeAg-negative sera. The most common missense mutation, a guanine to thymine transversion, occurred at nucleotide 1862 in the bulge of the encapsidation signal; it was more prevalent in HBeAg-negative (10/39) than in HBeAg-positive patients (1/23) (p = 0.03). Mutations known to prevent HBeAg synthesis were detected in seven sera; five with an 1896 stop-codon mutation, one with an 1817 nonsense mutation, and one with a frameshift mutation caused by an insertion between 1838 and 1839. Missense mutations and deletions were present more often in tumorous tissue derived from HBsAg-negative patients. In the tumours missense mutations occurred at position 1862 and 1899, and the deletions affected direct repeat 1 and/or the encapsidation signal and included the x gene stop-codon.

CONCLUSIONS

The 1862 mutation, and other missense mutations and deletions detected in the precore gene, may disrupt HBV DNA replication and/or signal peptide cleavage leading to HBeAg-negativity. Disruption of viral replication may promote integration of unencapsidated replicative intermediates and hence contribute to hepatocarcinogenesis.

Decreased nitric oxide production in chronic viral hepatitis B and C

Nitric oxide is a free radical gas molecule which may be implicated in antiviral defense. However, there is no information about its possible role in chronic viral hepatitis B and C. In this study we have analyzed the serum levels of NO2- (as an index of nitric oxide generation) from patients with chronic viral hepatitis B and C and relationship of same with the response to interferon therapy. Serum samples were analysed from 61 patients with chronic hepatitis B, 60 patients with chronic hepatitis C, 11 with chronic liver disease of nonviral origin, and 23 healthy controls. Levels of NO2- were statistically higher in healthy controls (P < 0.001) than in patients with chronic liver disease. No relation was found between NO2- and viremia or response to interferon therapy in patients with chronic hepatitis B. In contrast in chronic hepatitis C, responder patients had significantly higher NO2- than nonresponders (P < 0.01). With respect to the relation between NO2- levels and liver damage, patients with cirrhosis had lower NO2- levels than the rest of the patients (P < 0.001). In conclusion, patients with chronic viral hepatitis have low serum NO2- levels.

Efficacy of prolonged interferon-alpha treatment in chronic hepatitis B patients with HBeAb: comparison between 6 and 12 months of therapy

We compared the response and the relapse rates of HBeAb-positive patients treated with interferon-alpha for 6 or 12 months. Thirty-eight HBeAb-positive patients which chronic hepatitis B were randomly allocated into two groups: Group I (19 patients receiving 10 MU of recombinant interferon-alpha 2b three times a week for 2 months, followed by 5 MU three times a week for 2 months and then 3 MU three times a week for 2 months); Group II (19 patients receiving 10 MU of recombinant interferon-alpha 2b three times a week for 2 months, followed by 5 MU three times a week for 2 months and then 3 MU three times a week for 8 months). At the end of treatment, alanine aminotransferase normalization was higher but not more significant in Group I than in II (53% vs 26%), while hepatitis B virus DNA clearance was similar in both groups (21% in Group I vs 26% in Group II). However, at 12 months of follow-up, biochemical relapses occurred only in Group I (60% vs 0% in Groups I and II, respectively). Five complete responders cleared hepatitis B surface antigen at that time. In conclusion, prolonged treatment of HBeAb patients is efficient in reducing the biochemical relapse.

Distribution of the predominant hepatitis B virus precore variants in hepatitis B e antigen-positive children and their effect on treatment response

Little is known about the distribution of precore hepatitis B virus mutants and their influence on the outcome of interferon therapy in children with chronic hepatitis B. In this study, serum samples were analyzed from 60 children with chronic hepatitis B e antigen+ (HBeAg+) hepatitis. Fifty-two of these children underwent different interferon trials, and a second serum sample was taken from 25 of them at the end of therapy. Fifty-six of the original 60 children were simultaneously infected by wild-type and precore mutant hepatitis B virus variants. The remaining four children were infected by the wild type alone. In 50/56 of children with a mixed viral population, the wild-type variant comprised more than 50% of the total viremia. With respect to the influence of precore variants on the outcome of interferon treatment, the prevalence of mixed viral population was similar in responders and nonresponders (96 versus 88%, respectively). However, precore mutant variants were prevalent (> 50% of the viral population) in 21% of the nonresponders, but in none of the responder children (p < 0.05). Viremia levels were significantly higher in nonresponder than in responder children (p < 0.05). No substantial changes in the prevalence of mutants were observed throughout the interferon therapy. In conclusion, mixed viral infection is found in a high percentage of children with chronic B HBeAg+ hepatitis. Response to interferon therapy does not seem to be related to the presence of hepatitis B virus precore mutants, but rather to the levels of viremia.

Analysis of hepatitis B virus precore variants in hepatitis B e antibody-positive patients treated with prednisone plus interferon

To assess the effects of prednisone and interferon on the distribution of hepatitis B virus (HBV) precore mutants, nine hepatitis B e antibody (HBeAb)-positive patients with HBV chronic infection were studied. Patients were treated with prednisone (30 mg day-1 for 4 weeks, followed by 20 mg day-1 for 2 weeks and by 10 mg day-1 for 1 week), followed by recombinant interferon-alpha (15 MU thrice per week) for 6 months, without a clearance period. The HBV precore region was amplified by polymerase chain reaction (PCR) and distribution of the precore mutants was determined by hybridization of PCR products. Moreover, the glucocorticoid-responsive element (GRE) was sequenced to determine whether changes in the sequence were produced at the end of prednisone treatment. During prednisone treatment, changes in alanine transaminase (ALT) were observed in only two patients, in who ALT decreased to nearly normal values. In three patients ALT normalized at the end of interferon treatment. At baseline, wild-type HBV alone was detected in one patient, while seven patients were infected by a mixture of wild-type and precore mutants, predominantly wild type. At the end of prednisone treatment, two patients were infected by only wild-type HBV. The proportion of precore mutants decreased in three cases, while no changes were observed in three. At the end of interferon treatment, the precore mutant proportion decreased in the three responders, while tending to increase or remain unchanged in the rest. No significant changes in GRE sequence were found as a result of prednisone treatment. Our results would appear to confirm the role of the immune system in the selection of precore mutants.

The structure of hepatitis B envelope and molecular variants of hepatitis B virus

Accumulated evidence in recent years has shown that the variation of hepatitis B virus (HBV) genomes may have profound implications for our understanding of hepatitis B pathogenesis and prevention. Attention has focused on areas of the outer envelope coded by the S gene which are involved in the induction of a protective neutralising antibody response, and mutations which directly affect the production of C gene products, one of which is considered as a target for immune T cells involved in virus clearance. This review highlights recent experimental data which emphasizes the role of such mutations in the establishment and maintenance of chronic HBV infections and focuses attention on the significance of HBV variants with respect to the expanding use of HBV vaccines for mass immunization.