Relationship between the serum alanine aminotransferase level at the end of interferon treatment and histologic changes in wild-type and precore mutant hepatitis B virus infections

Summary Unravelling the role of interferon (IFN) in the treatment of chronic hepatitis B is complicated by many factors. Several mutant forms of hepatitis B virus (HBV) have recently been discovered; the most common of these is the precore mutant, characterized by hepatitis Be antigen (HBeAg) negativity and hepatitis Be antibody (HBeAb) positivity in an individual with an active HBV infection. The aim of this study was to compare the response rate to IFN therapy in patients with wild-type HBV infection and in individuals infected with the precore mutant. A second aim was to evaluate the role of an increased serum ferritin in terms of the IFN response rate in these two different types of HBV infection.
Therapy ministered at a dose of 5 MU subcutaneously three times weekly for 6 months to 41 individuals with a chronic wild-type hepatitis B infection and 16 individuals with a precore mutant chronic HBV infection. An IFN response was defined as normalization of the serum alanine aminotransferase (ALT) level and an HBeAg to HBeAb seroconversion (in wild-type hepatitis infection), and a normalization of the serum ALT in individuals infected with a precore mutant infection.
Ntrywo groups were matched for age, gender, serum ALT, serum iron, total iron binding capacity (TIBC), serum ferritin and liver histology. Forty-six per cent of the subjects with wild-type disease responded to IFN therapy. By contrast, only four of the 16 cases (25%) of the precore mutant cases responded ( P < 0.05). Ferritin levels correlated well with the type of IFN response; as the serum ferritin level increased, the response rate to IFN declined. Hapatic infection caused by a precore HBV mutant is more resistant to IFN therapy than wild-type infection. The serum ferritin level appears to influence the type of IFN response achieved. Individuals with a serum ferritin level greater than 300 ng ml^-1 failed to respond to IFN in 93% of the cases studied.     

Hepatitis B virus precore mutants in HBeAg carriers with chronic hepatitis treated with interferon

Summary. Precore mutants of hepatitis B virus (HBV) were looked for in 18 hepatitis B e antigen (HBeAg) carriers who were treated with recombinant interferon-a (rIFN) and the results were compared with those obtained in 12 untreated carriers who underwent spontaneous HBeAb seroconversion. Molecular analysis of the HBV precore region was carried out by polymerase chain reaction (PCR) amplification and direct sequencing. Precore mutants with a stop codon at codon 28 were detectable at baseline in 19/30 carriers. However, wild-type strains predominated in the baseline sera of both treated ( n = 16) and untreated ( n = 10) patients. Sera from the remaining four patients contained predominantly or exclusively mutant virions. Following IFN treatment, there was a shift from the wild-type pattern to the mutant pattern in all patients, with the precore pattern prevailing in long-term responders (six out of nine) compared with the non-responders (none of nine). The wild-type pattern predominated among the non-responders (eight vs three), suggesting that the long-term response to IFN was associated with take-over of precore mutants. There were no relationships between any pre-treatment precore molecular pattern and disease severity or outcome of treatment. Precore mutants also took over in 10 of the 12 untreated patients (83%), who underwent spontaneous HBeAb seroconversion. Thus, a shift from wild-type to precore mutant pattern occurs in most Italian patients undergoing IFN-induced or spontaneous HBeAb seroconversion.     

Appropriate use of interferon for treatment of chronic hepatitis B

Hepatitis B is not only a preventable but now treatable disease. Five drugs have been approved for the treatment of chronic hepatitis B virus (HBV) infection: standard interferon-α (IFN), pegylated IFN, lamivudine, adefovir dipivoxil and entecavir. Among these agents, the responses to interferon therapy are invariably influenced by both host and viral factors. Therefore, understanding these factors is important for practicing hepatologists, and it may help design individualized medicine for the treatment of chronic hepatitis B. HBV genotypes affect the disease progression and outcomes of HBV-related chronic liver disease, as well as the response to antiviral treatments. Existing data indicate a better sustained response to standard IFN-α in HBeAg positive genotype B patients than genotype C patients, and in genotype A patients than genotype D patients. Nevertheless, conflicting results exist regarding the response to pegylated IFN, and more studies are needed. As to HBV genetic polymorphisms, a recent study showed that an IFN sensitivity-determiningregion may not exist within the whole genome of HBV subgenotype Ba, and host factors as well as virus–host interactions may be more important than viral factors alone in determining the treatment outcomes with IFN. Regarding host genetic polymorphisms, single nucleotide polymorphisms within eukaryotic translation initiation factor 2 and MxA promoter regions may be associated with the responsiveness to standard IFN-α treatment in patients with HBeAg positive chronic hepatitis B. In the foreseeable future, individualized chronic hepatitis B treatment algorithms should be tailored to host (immune status, ALT level and genomic polymorphisms), virus (HBeAg status, HBV DNA level, genotype, precore/basal core promoter mutants and pre-S deletion mutant) as well as liver disease status (hepatitis activity and fibrosis stage).     

A novel primer-extension assay for the detection of a G to A mutation in the distal precore region of hepatitis B virus DNA

The roles of genetic heterogeneity of the hepatitis B virus (HBV) precore gene in the pathogenesis of HBV infection are unclear. Various methods have been used to detect nucleotide (nt) 1896 precore mutants. We established a new primer-extension assay to facilitate the detection of these mutants. This assay is based upon the fact that there is no adenine in the distal precore region of wild-type HBV. Polymerase chain reaction (PCR)-amplified template DNA was denatured and annealed to the [γ-³²P]-labelled primer. During primer extension in the presence of DNA polymerase and dCTP, dGTP, dTTP and ddATP, the reaction terminates if there is a nucleotide A. When mixtures of different ratios of wild-type and nt 1896 precore mutants were analysed in the primer-extension assay, correlation between the percentage known amounts and the percentage measured amounts of nt 1896 precore mutants was excellent (r²=0.9669). When the primer-extension assay and direct sequencing were compared in hepatitis B e antigen (HBeAg)-positive and -negative chronic active hepatitis B patients, the primer-extension assay detected a greater number of nt 1896 precore mutants than direct sequencing and thus most HBV infections were found to be mixed infections. In conclusion, the primer-extension assay is a reliable and sensitive method for the detection of nt 1896 precore mutants.     

Precore and X region mutants in hepatitis B virus infections among renal dialysis patients

SUMMARY. Hepatitis B virus (HBV) variants containing mutations within the X and the precore regions of the viral genome were demonstrated by polymerase chain reaction (PCR) amplification and DNA sequencing in renal dialysis patients with different serological patterns of HBV infection. Among carriers, X region deletion mutants predominated in patients who lost hepatitis B e antigen (HBeAg), or developed anti-HBe, but not in persistently HBeAg-positive patients. The precore region remained wild type in all carriers whether or not they seroconverted from HBeAg to anti-HBe. The frequency of precore and X region mutants was greatest among non-carrier patients with viral antibodies as the only indication of infection and among patients with non-A, non-B hepatitis (NANBH), suggesting an inverse relationship between the presence of wild type HBV markers and the presence of HBV mutants. Furthermore, the detection of one but not the other mutation in many serum samples suggests that these mutations are independently selected for during infection. Finally, the absence of HBV DNA in 21 'uninfected' dialysis patients with normal transaminases and no viral serology, suggests that replication of these mutants is associated with hepatitis. These results have important implications for HBV screening and treatment, as well as for the pathogenesis of chronic infection.     

Hepatitis B virus precore mutations and HBeAg negative reactivation of chronic hepatitis B after interferon therapy

The objective of this study was to look for HBV precore mutations in three patients with chronic active hepatitis B who developed HBV-DNA-positive/HBeAg-negative reactivation after HBe seroconversion induced by interferon therapy. Direct sequencing of polymerase chain reaction products was performed on serum collected before and after HBe seroconversion. In two patients precore sequence showed only wild-type HBV before and after interferon therapy. In one patient, precore sequence showed only wild-type HBV before interferon therapy and a mixed infection by wild-type HBV and precore mutant viruses (1858 and 1896 nucleotide mutations) after treatment. The presence of HBeAg/anti-HBe immune complexes was found after HBe seroconversion in all cases. Our results suggest that: 1) precore mutations are not always found in patients with chronic hepatitis B who develop HBV DNA-positive/HBeAg-negative reactivation; and 2) HBeAg negativity, despite the presence of wild-type HBV, might be due to HBeAg/anti-HBe immune complexes. We speculate that the production of these immune complexes may be favored by interferon therapy.     

Relationship of clinical and virological factors with hepatitis activity in hepatitis B e antigen-negative chronic hepatitis B virus-infected patients

To investigate the factors associated with active disease among hepatitis B surface antigen (HBsAg) positive/hepatitis B e antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infection we studied chronic HBV infected patients who had undetectable HBeAg at the first visit. HBV DNA was determined by the cross-linking assay (NAXCOR) and polymerase chain reaction (PCR). Mutations in the core promoter and precore regions and viral genotypes were studied. Clinical outcome of these patients were followed and categorized as: (i) relapse (ALT > 200 IU/L or three times the previous levels); (ii) active hepatitis (elevated ALT < 200 IU/L with concomitant detectable HBV DNA); or (iii) remission. A total of eighty-five patients were followed up for 5.5 ± 1.0 years. At first visit, 31 (36.5%) patients had elevated ALT levels, 12 (14.1%) had measurable HBV DNA by the cross-linking assay and 26 (30.6%) by PCR. Sixteen (18.8%) patients had hepatitis relapse, 13 (15.3%) had active hepatitis, and 56 (65.9%) remained in remission. Core promoter and precore stop codon mutants were found in 27 and 12 patients, respectively. Eleven and 20 had genotype B and C HBV, respectively. Initial elevated ALT and detectable HBV DNA were associated with active liver disease. Patient demographics, viral mutants or genotypes failed to predict disease activity. Hence, serum ALT and HBV DNA levels offer the best prediction of natural course of HBeAg-negative chronic HBV infection.     

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

Summary. 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-α (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 whom 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.     

Hepatitis B e antigen negative chronic active hepatitis: hepatitis B virus core mutations occur predominantly in known antigenic determinants

Summary. In chronic hepatitis B virus (HBV) infection seroconversion from hepatitis B e antigen (HBeAg) to hepatitis B e antibody (HBeAb) may be followed either by remission of the disease with low-level viraemia, or by continuing inflammation with high-level viraemia. In both situations the virus may acquire a mutation in the precore sequence which prevents it from encoding HBeAg. We now show that the number of amino acid substitutions in the HBV core is low in viral sequences from patients with HBeAg positive chronic liver disease and HBeAg negative HBeAb positive patients in remission, but the frequency of substitutions is high in HBeAg, negative HBeAb positive patients with active liver disease. Furthermore we show that these substitutions cluster in the promiscuous CD4⁺ T-helper-cell epitope and in HBV core/e antibody binding determinants, but are not found in regions recognized by major histocompatability complex (MHC) restricted cytotoxic T lymphocytes. Sequential viral sequences from patients before and after HBeAg/HbeAb seroconversion shows that core mutations arise either at the same time or after the precore stop mutation which prevents the virus from encoding HBeAg. These results are consistent with the hypothesis that after clearance of HBeAg, mutations in regions of the virus recognized by CD4⁺ helper T cells and B cells allow persistence of the HBe negative virus in HBeAb positive patients with viraemia and active hepatitis.     

Three-phase sequential combined treatment with lamivudine and interferon in young patients with chronic hepatitis B

Alpha-interferon (IFN) or lamivudine monotherapy are ineffective in treating chronic HBeAg positive patients with high viral load and low alanine aminotransferase (ALT) levels. We investigated whether priming lamivudine treatment might enhance the antiviral and immunostimulant action of lamivudine/IFN combination in young tolerant patients. Eleven chronic HBeAg positive patients received: 100 mg/day lamivudine for 3 months followed by IFN 5 MU/m2/tiw with lamivudine 100 mg/day for 6 months and then lamivudine alone 100 mg/day for 9 months. Quantitative hepatitis B virus (HBV)-DNA was evaluated during treatment and core-promoter, precore and polymerase HBV mutants were detected by direct sequencing at the end of therapy. Serum HBV-DNA levels dropped during lamivudine monotherapy and in combination with IFN. After IFN withdrawal, viraemia transiently increased to high levels in five of 11 (45%) patients who showed rt M204V/I lamivudine mutant resistant. Two patients cleared HBeAg without anti-HBe seroconversion. One patient presented core-promoter (A1762T/G1764A) and precore stop codon mutations. Hence, three-phase sequential combined lamivudine/IFN treatment reduced HBV-DNA serum level, but did not lead to HBeAg and HBV-DNA clearance in these highly viraemic, normal ALT patients. Lamivudine/IFN combination did not prevent the emergence of YMDD lamivudine resistance. New schedules of antiviral treatments must be evaluated in this population at risk of disease progression.     

Long-term effects of interferon-α in five HIV-positive patients with chronic hepatitis B

Summary. Chronic hepatitis B viral infection is common in human immunodeficiency virus (HIV) carriers, but the effectiveness of interferon therapy is still unknown. We report the results of a long-term pilot study of five patients, who were infected with HIV and chronic hepatitis B, treated by interferon. Five males co-infected with HIV and hepatitis B virus (HBV) (mean age 2 7 years) were given a 6-month course of interferon (IFN)-α2b 5 million units (MU) three times weekly. On initiating the treatment, their CD4 lymphocyte count was 340–553 mm^-3, their CDC stage was IIa-III; all had histologically proven chronic hepatitis, with Knodell's score ranging from 6–10, and active HBV replication (HBV DNA and hepatitis B e antigen (HBeAg) were detectable). There was no associated hepatitis δ virus (HδV) or hepatitis C virus (HCV) infection. Follow-up was for 53 months on average (24–74 months). After the treatment, hepatitis B e antibody (HBeAb) and hepatitis B s antibody (HBsAb) sero-conversion was observed in one patient, HBeAb seroconversion alone in two patients, HBV DNA was absent from serum in three patients, and HBV DNA significantly decreased in one patient. The serum alanine aminotransferase (ALT) activity was normal in four patients. Histological improvement was obtained in four patients. The HIV stage remained unchanged in all patients during the whole follow-up. These preliminary results suggest that interferon can be successfully used in immunocompetent HIV carriers with chronic hepatitis B as well as in HIV-negative patients.     

Long-term interferon-α treatment of children with chronic hepatitis delta: a multicentre study

Summary We assessed the efficacy of prolonged interferon-α (IFN) therapy in children with chronic hepatitis caused by hepatitis delta virus (HDV) by treating 26 paediatric cases with IFN-α2b(5 MU m^-2, then 3 MU m^-2 three times weekly for 12 (medium-term group, MTG) or 24 months (long-term group, LTG). Compliance and tolerability were acceptable. At the end of therapy a complete biochemical response [normalization of alanine aminotransferase (ALT)] occurred in 12 children (5/13 in MTG and 7/13 in LTG). A relapse occurred after stopping IFN in 10 cases (five in MTG and five in LTG). Two patients from the LTG had normal liver function tests during 12 months of follow-up. Six of the eight hepatitis Be antigen (HBeAg) positive children lost HBeAg, while all six hepatitis B virus (HBV) DNA positive patients lost HBV DNA during treatment. HBeAg reappeared later in two children. HDV RNA, present in 10/10 cases of MTG before treatment, persisted after 12 months IFN therapy in 3/10. One year after stopping therapy, 8/10 patients were again HDV RNA positive. Two children cleared hepatitis delta antigen (HDVAg) from the liver. No significant improvements in liver histology were seen in both groups. Our experience suggests that IFN-α treatment in children with chronic type D hepatitis has a transient effect, and long-term treatment does not appear to induce a greater therapeutic benefit in terms of biochemical and virological response.     

Difference in T helper responses during hepatitis flares in hepatitis B e antigen (HBeAg)-positive patients with genotypes B and C: implication for early HBeAg seroconversion

The underlying mechanisms for earlier hepatitis B e antigen (HBeAg) seroconversion in patients with chronic hepatitis B virus (HBV) genotype B when compared with genotype C are unknown. We aimed to determine whether there were any differences in the T helper (Th) responses during hepatitis flares in HBeAg-positive patients with genotypes B and C. Proliferative response measured by (3)H-thymidine uptake and Th responses measured by Enzyme-Linked Immunosorbent Spot assays for interleukin (IL)-2, interferon-gamma (IFN-gamma), IL-4, IL-5 and IL-10 were performed in 10 patients with genotype B and 10 with genotype C with hepatitis flares. HBV genotypes, core promoter, precore mutations, sequence of HBV core region and HBV DNA levels were determined. There was no difference in the HBV DNA levels during hepatitis flares between patients with genotypes B and C. Patients with genotype B had a significantly higher number of IFN-gamma producing cells [with hepatitis B core antigen (HBcAg) stimulation] and lower number of IL-10 producing cells (with HBcAg and HBeAg stimulation) compared with patients with genotype C (P = 0.011, =0.043, <0.001 respectively). There was a trend (P = 0.058) that patients with genotype B had a higher cumulative rate of HBeAg seroconversion. Patients with precore mutants also had a significantly higher number of IFN-gamma producing cells (with HBcAg stimulation) and lower number of IL-10 producing cells (with HBeAg stimulation) compared to patients without precore mutant (P = 0.038, =0.016 respectively). HBV genotype B induces a greater Th1 and lesser Th2 response than genotype C. This provides immunologic evidence for the higher chance of HBeAg seroconversion in patients with genotype B.     

乙型肝炎患者血清Pre-S-2抗原的意义

目的研究ＰｒｅＳ２抗原与乙型肝炎患者ＨＢＶ标记的关系．方法血清ＨＢｓＡｇ（＋），ＨＢｅＡｇ（＋），ＨＢｃＡｂ（＋）的乙型肝炎患者２６例，血清ＨＢｓＡｇ（＋），ＨＢｅＡｂ（＋），ＨＢｃＡｂ（＋）的乙型肝炎患者４７例及健康献血者２０例，血清用ＲＩＡ法检测ＰｒｅＳ２抗原及用ＰＣＲ法检测ＨＢＶＤＮＡ．结果血清ＨＢｓＡｇ（＋），ＨＢｅＡｇ（＋），ＨＢｃＡｂ（＋）的乙型肝炎患者２６例，ＰｒｅＳ２抗原与ＨＢＶＤＮＡ均阳性（１００％）；血清ＨＢｓＡｇ（＋），ＨＢｅＡｂ（＋），ＨＢｃＡｂ（＋）的乙型肝炎患者４７例，ＰｒｅＳ２抗原３０例阳性（６３８％），１７例阴性（３６２％），ＨＢＶＤＮＡ３２例阳性（６８１％），１５例阴性（３１９％），ＰｒｅＳ２抗原与ＨＢＶＤＮＡ均阳性２８例（５９６％），均阴性１４例（３００％）．健康献血者２０例，ＰｒｅＳ２抗原阳性１例（５０％），阴性１９例（９５０％），ＨＢＶＤＮＡ阳性２例（１００％），阴性１８例（８００％），ＰｒｅＳ２抗原及ＨＢＶＤＮＡ均阳性０例（０％），均阴性１８例（８００％）．结论ＰｒｅＳ２抗原可作为预测慢性乙型肝炎患者病情活动与传染的标志．     

Clinical characteristics and distribution of hepatitis B virus genotypes in Guangxi Zhuang population

AIM: To investigate the distribution of HBV genotypes and their YMDD mutations in Guangxi Zhuang population, China, and to study the relationship between HBV genotypes and clinical types of HB, ALT, HBV DNA, HBe system as well as the curative effect of Lamivudine (LAM) on hepatitis B. METHODS: A total of 156 cases were randomly chosen as study subjects from 317 patients with chronic hepatitis B (CHB). HBV genotypes were determined by PCR-microcosmic nucleic acid cross-ELISA. YMDD mutations were detected by microcosmic nucleic acid cross-nucleic acid quantitative determination. HBV DNA was detected by fluorescence ratio PCR analysis. LAM was given to 81 cases and its curative effect was observed by measuring ALT, HBV DNA load, HBeAg, and HBeAg/HBeAb conversion rate. RESULTS: HBV genotypes B, C, D, and non-classified genotypes were found in Guangxi Zhuang population, accounting for 25.6%, 47.4%, 58.3%, and 16.0%, respectively. Seventy-four cases were CD-, CB-, BD-mixed genotypes (47.7%). Forty-six (29.5%) cases had YMDD mutations. Genotype B was mostly found in mild and moderate CHB patients. Genotypes C, D and mixed genotype mostly occurred in severe CHB cases. Genotypes D and CD HBV-infected patients had higher ALT and HBV DNA than patients with other types of HBV infection. There was no significant difference among the genotypes in YMDD mutations, clinical types, ALT and HBV DNA level. Non-classified types geno had a significantly lower positive rate of HBeAg than other genotypes (X2=12.841,P<0.05). There was no significant difference in ALT recovery rate, HBV DNA load, HBeAg, and HBeAg/HBeAb conversion rate, 48 wk after LAM treatment between groups of genotypes D, CD, and non-classified type. CONCLUSION: Genotypes B, C, and D, non-classified and mixed genotype of HBV are identified in the Guangxi Zhuang population. Variations in genotypes are associated with clinical severity and serum ALT levels, but not with YMDD mutation or HBV DNA load. Therapeutic effects of LAM on clinical parameters are not influenced by differences in genotypes. Further studies are needed to gain an in-depth understanding of the relationship between HBV genotypes and serum HBeAb and HBeAg.     

Frequent integration of precore/core mutants of hepatitis B virus in human hepatocellular carcinoma tissues

The development of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) frequently follows persistent HBV infection and may arise in individuals who are hepatitis B e antigen (HBeAg) negative, indicating the possible presence of precore/core mutants. It is unclear whether precore/core mutants are associated with tumour development or are selected for after chromosomal integration of the wild-type viral DNA. We studied the status and sequence variation of the precore/core region of HBV in 56 patients with HBV-associated HCC and in various corresponding non-tumour tissues by Southern blot analysis, polymerase chain reaction and direct sequencing. Southern blot showed that integrated HBV DNA existed in 43 of 56 HCC tissues. Sequence analysis revealed mutations in 65% of the HCC (26/40) and 45% (14/31) of the corresponding non-tumour tissues. The mutation at nucleotide (nt) 1896, known to prevent HBeAg synthesis, was detected in 40% (16/40) of the tumours and in 35.4% (11/31) of the non-tumour tissues. Other mutations were found at nt 1899 (eight of 40 in HCC; three of 31 in non-tumour tissues), nt 1898 (seven of 40 in HCC; two of 31 in non-tumour tissues), nt 1912 (seven of 40 in HCC; none of 31 in non-tumour tissues) and nt 1886 (three of 40 in HCC; none of 31 in non-tumour tissues). To determine whether this finding merely reflected the prevalence of such mutants in this geographical region, HBV DNA from the sera of patients (also in this region) with acute and chronic hepatitis were sequenced. The nt 1896 mutant was found in 5.6% (one of 18) of patients with acute hepatitis B and in 22.8% (nine of 35) of patients with chronic hepatitis B. However, the nt 1898 mutation was not found in any of these sera. The precore/core mutant was observed with increasing frequency from acute hepatitis to chronic hepatitis, non-tumour and HCC, and this difference in frequency was significant between HCC and acute hepatitis B groups (P < 0.01), suggesting that the precore/core mutant or hepatocytes harbouring this mutant may be under immune selection and that such mutations may facilitate integration and subsequent tumour development.     

Incidence and clinical significance of hepatitis B virus precore gene translation initiation mutations in e antigen-negative patients

Hepatitis Be antigen (HBeAg)-negative chronic hepatitis B (CHB) is associated with hepatitis B virus (HBV) variants harbouring changes in the precore region. Most commonly, a G to A point mutation at nucleotide 1896 (m1896) creates a novel translation stop codon that prevents HBeAg production. In the Mediterranean region the m1896 mutation prevails in greater than 98% of HBeAg-negative CHB patients. In this study the prevalence of additional mutations in the precore region was investigated among patients with chronic HBV infection. Precore sequences were determined by sequencing serum HBV DNA amplified by polymerase chain reaction (PCR) with primers flanking the precore/core region. Thirty-one HBeAg-negative and five HBeAg-positive individuals were studied. All HBeAg-negative patients (100%) harboured the m1896 mutation and 20 (64.5%) also had a G to A mutation at nucleotide 1899 (m1899). Additional mutations affecting the translation initiation of the precore gene were found in seven (22.5%) patients, all with active liver disease, five of whom had episodes of HBV reactivation. HBeAg-positive patients had no mutations in these positions and neither did any of the five HBeAg-negative patients with normal levels of liver enzymes, representing the healthy carrier state of HBV infection. Serial sample analysis from one patient revealed that the initiation codon mutation developed following HBeAg seroconversion and the appearance of m1896. During periods of high HBV replication, the ratio of mutant to wild-type ATG was found to increase in parallel with HBV DNA levels. These data show that a significant proportion of HBeAg-negative patients who already harbour the 1896 stop codon mutation may subsequently develop precore translation initiation mutations, which appear to be associated with enhanced HBV replication and severe liver disease.     

Analysis of the precore DNA sequence and detection of precore antigen in liver specimens from patients with anti-hepatitis B e-positive chronic hepatitis

A number of naturally occurring hepatitis B virus (HBV) mutants unable to synthesize the hepatitis B e antigen (HBeAg) have been identified in patients characterized by HBV DNA and anti-HBe in their serum. Because the analysis of the HBV-associated DNA and antigens in the liver tissue is still not complete, we investigated the precore sequence of HBV DNA and its encoded proteins in the liver tissue of 32 patients positive for HBV DNA and anti-HBe in their serum. Three different groups of patients were identified. Group I (n = 14) was characterized by viral DNA sequences with a G-A transition in the distal precore gene region, thus creating a termination codon (TAG). Liver tissue from this group was negative for HBeAg but positive for hepatitis B core antigen (HBcAg) and a peptide containing the last 10 aminoacids of the precore and the first four aminoacids of the c region. Group II (n = 6) showed variable mutations in base sequences further upstream and negative for HBeAg and the precore peptide. Group III (n = 12) contained wild-type HBV DNA sequences in the tissue and positivity for precore- and core-encoded proteins. We conclude from our study that the group of patients with HBV DNA and anti-HBe in the serum is rather heterogeneous, including HBV DNA mutations in the precore region as well as infection with the wild-type virus being negative for HBeAg in the serum. The precore peptide is produced and expressed in the tissue even when the formation of a stop codon at base 1896 prevents the complete translation of the entire HBe protein.     

乙型肝炎患者血清中HBcAg与HBV复制指标的关系

目的探讨乙型肝炎患者血清ＨＢｃＡｇ与ＨＢＶ复制指标的关系及临床意义．方法对３１１例乙型肝炎患者进行了ＨＢｃＡｇ检测，并同时进行酶联法乙肝五项、地高辛法ＨＢＶＤＮＡ检测，其中２３７例进行乙肝ＤＮＡ聚合酶（ＤＮＡＰ）检测．结果ＨＢｃＡｇ阳性组的ＨＢＶＤＮＡ检出率（７７６％），明显高于ＨＢｃＡｇ阴性组（３５５％，Ｐ＜００１）；在ＨＢｃＡｇ阴性组中，抗ＨＢｅ阳性者仍能检出２９９％（４４／１４７）ＨＢＶＤＮＡ者阳性；ＨＢｅＡｇ，ＨＢｃＡｇ均阳性者其ＨＢＶＤＮＡ和ＤＮＡＰ的检出率高达８５９％；其他依次为ＨＢｅＡｇ、抗ＨＢｅ和ＨＢｃＡｇ均阳性者７１４％，抗ＨＢｅ，ＨＢｃＡｇ阳性者６９２％，ＨＢｅＡｇ阳性，ＨＢｃＡｇ阴性者６８４％，抗ＨＢｅ阳性，ＨＢｃＡｇ阴性者２７６％．结论血清ＨＢＶＤＮＡ，ＤＮＡＰ，ＨＢｅＡｇ和ＨＢｃＡｇ均是反映乙肝病毒复制的敏感指标，抗ＨＢｅ的出现并不表示病毒复制停止，应参考其他病毒复制指标情况．各种指标的不同组合可以清楚地反映出患者体内病毒复制状况．