Natural YMDD Motif Mutations of HBV Polymerase in the Chronic Hepatitis B Virus Infected Patients / 대한간학회지

BACKGROUND/AIMS: Lamivudine, a nucleoside analogue has been widely used as an effective antiviral agent for the treatment of patients with chronic hepatitis B infection. However, the YMDD motif mutation of HBV polymerase resistant to lamivudine very frequently occurs after long-term use of lamivudine. It is well known that the mutation is selected by the lamivudine. We hypothesized that a few mutant strains of YMDD motif are present as quasispacies before the lamivudine treatment, are selected by the treatment, and breakthrough during treatment. We investigated the prevalence of the YMDD motif mutants in patients with chronic hepatitis B infection who had not been treated by antiviral agents before. METHODS: The study included the serums of 40 patients with chronic heptitis B infection, which stored at -70 degrees C. Thirty-four patients had chronic hepatitis and 6 patients had cirrhosis. Thirty-one patients were diagnosed by liver biopsy. The average age and range were 29 years and 13-57 years respectively. None had taken any antiviral agents before. To detect YMDD mutants, YVDD (M552V), and YIDD (M552I), we used direct sequencing and the restriction fragment length polymorphism (RFLP) method. RESULTS: The YMDD mutant was detected by RFLP method in 7.5% (3/40) of the patients with chronic hepatitis B infection, in two patients with chronic hepatitis and one with cirrhosis. All were YMDD+ YIDD mutants. CONCLUSIONS: The YMDD motif mutation occurs spontaneously without antiviral therapy in patients with chronic hepatitis B infection.

Efficacy of Lamivudine in Patients with Hepatitis B e Antigen-Negative Chronic Liver Diseases / 대한간학회지

BACKGROUND/AIMS: Lamivudine therapy is effective in inhibiting HBV replications in patients with HBeAg-negative chronic liver disease. However, the sustained response rate appears to be particularly poor, because the vast majority of patients relapse soon after cessation of therapy. The aim of this study was to evaluate the efficacy of lamivudine, the breakthrough rate, and the relapse rate of discontinuing therapy after response in patients with HBeAg-negative chronic liver disease. METHODS: Fifty-nine patients with HBeAg-negative chronic liver disease who have received lamivudine for at least 6 months, were studied. The mean duration of treatment was 14 months. Complete response was defined as undetectable serum HBV DNA by bDNA and normalization of ALT levels. Once HBV DNA disappearance and ALT normalization were observed, lamivudine therapy was continued for at least two additional months. The mean follow-up after cessation of treatment was 6 (1-22) months. RESULTS: Fifty-six patients were undetectable HBV DNA. The cumulative HBV DNA loss rates at 3 months and 5 months were 90% and 95%, respectively. The ALT normalization was observed in 52 patients. The cumulative ALT normalization rates at 6 months and 10 months were 78% and 86%, respectively. The complete response was observed in 52 patients. The cumulative rates of complete response at 10 months and 18 months were 80% and 88%, respectively. A predictive factor for complete response was only the duration of lamivudine treatment. Virological breakthrough was observed in 5 (8.5%). Thirty-four patients stopped taking lamivudine after 7.7 (2-15) months of the additional therapy. Seventeen of those patients (50%) experienced relapse. The cumulative relapse rates at 3 months, 6 months and 10 months were 24%, 47%, and 66%, respectively. The only predictive factor for relapse was the duration of additional lamivudine treatment after response. CONCLUSIONS: Lamivudine was an effective treatment of HBeAg negative chronic liver disease. Relapse, however, was usually observed after cessation of lamivudine. Our results showed that long-term lamivudine therapy is required in order to decrease the high relapse rates in patients with HBeAg-negative chronic liver disease.

Chemokine Receptor Expression of Hepatitis B Virus-Specific CD8+ Lymphocyte in Chronic B Viral Infection / 대한간학회지

BACKGROUND/AIMS: The protective role of HBV-specific CD8+ cells is dependent on their ability to efficiently migrate to the infected liver, where they may exert an effector function. The migratory behavior of CD8+ cells is influenced by their expression of different chemokine receptors. This study was intended to analyse the pattern of chemokine receptor expression of HBV specific CD 8+ cells in chronic B viral infection. METHODS: We analysed the CCR5 and CCR3 profile of HBV-specific CD8+ cells isolated from the blood and liver of patients with different patterns of HBV infection. Purified T cells were stained directly ex vivo, or after antigen-specific stimulation, using HBV peptide-specific HLA tetramers and monoclonal antibodies to CD8, CCR5 and CCR3, with analysis by flow cytometry. RESULTS: In patients with chronic hepatitis B characterised by low levels of virus (serum HBV DNA <0.5pg/mL) and minimal liver inflammation, analysis of circulating and intrahepatic CD8+ cells demonstrated that liver infiltrating Tc18-27-specific cells were preferentially CCR5+ (up to 80% of HBV-specific CD8+ cells), in contrast to cells of the same specificity within the circulating compartment (up to 35% of HBV-specific CD8+ cells). Furthermore, CCR3 was expressed by about 10% of Tc18-27+ cells infiltrating the liver, but was absent from circulating cells. Following HBV-specific stimulation in vitro the CCR5 expression of circulating Tc18-27-specific cells was up-regulated, to levels found in liver infiltrating cells, whereas CCR3 expression was unchanged. CONCLUSIONS: The chemokine receptor profile of HBV-specific CD8+ cells is influenced by the anatomical site of these cells, and the clinical pattern of disease. The ability of circulating HBV-specific CD8+ cells of patients with low replicating virus to upregulate CCR5 suggests that these cells may respond to increases in virus replication by efficiently migrating into the infected liver.

Relationship Between Core Gene Mutations of Hepatitis B Virus and Response to Alpha Interferon Therapy in Chronic Hepatitis B / 대한간학회지

BACKGROUND/AIMS: Treatment of chronic hepatitis B with interferon results in a sustained loss of hepatitis B virus DNA and hepatitis B e antigen (HBeAg) and remission of liver disease only in a proportion of cases. Recently, mutations of hepatitis B virus (HBV) core gene have been reported as being related to the failure of interferon treatment in chronic hepatitis B. This study investigated whether core gene mutations of HBV are related to non-response to interferon therapy and whether the recurrence of HBeAg and HBV DNA in initial responders to interferon therapy is associated with the emergence of HBV core gene mutants. METHODS: The precore/core gene sequence was determined by polymerase chain reaction (PCR) and direct sequencing of PCR product in serum samples obtained before interferon treatment from 10 responders and 10 non-responders to interferon therapy. In addition, precore/core gene sequence was determined in serum samples obtained before interferon treatment and after recurrence from 10 patients who showed recurrence of HBeAg and HBV DNA after initial response to interferon therapy. RESULTS: In samples from 10 responders, there were 7 missense mutations and 71 silent mutations. However, there were 43 missense mutations and 109 silent mutations in samples from 10 non-responders. In samples obtained before interferon treatment from the 10 patients who showed recurrence after initial response, 8 missense mutations and 74 silents mutations were found. The nucleotide sequences from the samples obtained after the recurrence showed 6 silent nucleotide substitutions compared with the sequences from the samples obtained before interferon treatment. CONCLUSIONS: Mutations in the core protein of HBV occur more frequently in non-responders than responders to interferon therapy of chronic hepatitis B and may be a factor responsible for the failure of interferon treatment. The recurrence of HBeAg and HBV-DNA in initial responders to interferon therapy is not associated with the emergence of the HBV core gene mutants.

Clinical Outcome in Cases of Viral Breakthrough During Lamivudine Therapy in Chronic Hepatitis B Patients / 대한간학회지

BACKGROUND/AIMS: Long-term lamivudine therapy can induce the emergence of lamivudine resistant hepatitis B virus (HBV) mutants. Clinically emergence of the mutant is expressed by the reappearance of disappeared HBV DNA in serum. Continued lamivudine treatment has been usually recommended in cases of viral breakthrough. However, the clinical outcome in patients with viral breakthrough is not clear. The aim of this study was to investigate the clinical course of chronic hepatitis B patients after viral breakthrough during lamivudine therapy. METHODS: A total of 74 patients with chronic hepatitis B who showed viral breakthrough after at least 6 months of lamivudine treatment were included in this study. They had positive HBeAg and HBV DNA before treatment. The median follow-up duration after breakthrough was 13 months. RESULTS: After viral breakthrough, only 8 patients (11%) maintained normal ALT levels and 66 patients (89%) showed elevation of ALT. 30 patients (41%) showed acute exacerbation of hepatitis (ALT increase over five-times upper normal limit). These acute exacerbations occurred within three months after breakthrough in 19 patients (63%). In the cases of acute exacerbation, 6 patients showed decompensated progression such as elevation of serum total bilirubin. One of them died of hepatic failure. A predictive factor for acute exacerbation was not found. HBeAg seroconversion occurred in 8 patients after viral breakthrough but their clinical course was highly variable. CONCLUSIONS: Chronic hepatitis B patients who had viral breakthrough during lamivudine therapy should be followed carefully and regularly in mind of potential clinical deterioration. New strategies are needed to manage the cases of acute exacerbation after viral breakthrough.

Viral Breakthrough in HBeAg-Negative Chronic Hepatitis B Patients Receiving Lamivudine Therapy / 대한간학회지

BACKGROUND/AIMS: Long-term efficacy and the rate of viral breakthrough in patients with HBeAg- negative chronic hepatitis B receiving lamivudine therapy is uncertain. This study was conducted to determine the rate of viral breakthrough according to the HBeAg status and the relation of viral breakthrough with YMDD mutants. METHODS: Two hundred and five patients with HBeAg-positive and 49 patients with HBeAg-negative chronic hepatitis B, who had received lamivudine for at least 9 months, were included. The mean durations of the lamivudine treatment were 176 months and 155 months in HBeAg-positive and negative patients, respectively. Analysis of HBV genome for YMDD mutations was performed by restriction-fragment-length polymorphism assay and direct sequencing. RESULTS: While the cumulative rates of viral breakthrough at 12th and 24th months of the lamivudine therapy were 0% and 7% in the HBeAg-negative group, they were 12% and 39% in the HBeAg-positive group. The cumulative rate of viral breakthrough in the HBeAg-negative group was significantly lower than in the HBeAg-positive group (p<0.01). In multivariate analysis, the only significant factor related to viral breakthrough was the HBeAg status (p<0.05). The YMDD mutants were detected in all patients with viral breakthrough irrespective of HBeAg status. However, in patients without viral breakthrough, the rate of YMDD mutants was significantly higher in the HBeAg-negative group than in the HBeAg-positive group (13.3% vs 5.1%; p<0.01). CONCLUSIONS: Lamivudine is expected to be more persistently effective in HBeAg-negative chronic hepatitis B because of a lower viral breakthrough rate than in HBeAg-positive chronic hepatitis B in spite of the emergence of YMDD mutants.

Clinical and Virologic Characteristics of Lamivudine Resistance in HBV-associated Chronic Liver Disease / 대한간학회지

BACKGROUND/AIMS: Lamivudine therapy in chronic hepatitis B has been shown to be effective in inhibiting HBV replication. However, lamivudine resistance has been developed with prolonged use. We studied to determine the prevalence, predictive factors, and clinical outcomes of lamivudine resistance. Mutations in YMDD motif of HBV polymerase, which have been associated with lamivudine resistance, were also assessed. METHODS: 170 patients with HBV-associated chronic liver disease who have received lamivudine for at least one year, were studied. The clinical, biochemical, and virologic characteristics were analyzed and compared according to presence (resistance group) or absence (non-resistance group) of DNA breakthrough. Their clinical outcomes were regularly followed. Stored sera before treatment and after DNA breakthrough were examined for detection of HBV polymerase mutation by direct sequencing and/or RFLP. RESULTS: Cumulative rates of lamivudine resistance after one and two years of treatment were 11% and 34%, respectively. In the resistance group, as compared to the non-resistance group, age, the presence of HBeAg before treatment, and disappearance of HBeAg during treatment, were significantly different. The predictive factors associated with lamivudine resistance were not found. ALT and HBV-DNA level after lamivudine resistance was variable, but jaundice or hepatic failure was absent. Mutation in YMDD motif was detected in 73% and other variable mutations were detected before treatment and after DNA breakthrough. CONCLUSIONS: Lamivudine resistance increases the longer the duration of treatment and clinical outcomes are variable. The mutation in YMDD motif was found in about 2/3 of cases. Other causes for lamivudine resistance may be considered.

Efficacy of 1-Year Lamivudine Treatment in the Patient of Chronic B Hepatitis and Liver Cirrhosis / 대한간학회지

BACKGROUND/AIMS: Lamivudine is highly effective in suppressing hepatitis B virus replication and hepatitis B induced necroinflammatory activity. The objective of this study was to evaluate the virological and biochemical responses to lamivudine by patients with HBV associated chronic liver disease. In particular we stressed the importance of lamivudine therapy by patients with decompensated liver cirrhosis. METHODS: We conducted a one-year trial of lamivudine in 80 patients with HBV associated chronic liver disease (chronic hepatitis 44, cirrhosis 36). We classified these patients according to the severity of hepatic dysfunction as chronic B hepatitis (Group A) or liver cirrhosis (Group B). These patients were treated for 12 months with 100 mg daily doses of lamivudine. RESULTS: The seroconversion rate of HBeAg was 23.5% in group A patients and 26.7% in group B patients. The negative conversion of HBV-DNA was sustained for one year in 79.5% of patients in group A and 86.1% in group B. The normalization rates of serum ALT were 90.9% in group A and 88.9% in group B patients. No serious side effect after discontinuance of the treatment was found. There were 12 ALT breakthrough cases and all of them showed mutation of YMDD motif. However, they did not deteriorate clinically in spite of ALT elevation and HBV-DNA reappearance. The Child-Pugh scores improved even in patients with decompensated liver cirrhosis. CONCLUSION: One-year lamivudine treatment resulted in excellent virological and biochemical improvements and was well tolerated in the patients with HBV associated chronic liver disease, even in decompensated cirrhosis. We conclude that lamivudine is relatively safe in chronic hepatitis B and liver cirrhosis treatment.

Prevalence of HBV Genotypes in Korean Patients with Chronic Hepatitis B / 대한간학회지

BACKGROUND/AIMS: Hepatitis B virus (HBV) genotypes have distinct geographic distributions. The possibility of pathogenic differences among HBV genotypes has been suggested. We investigated the prevalence of HBV genotypes in Korea and the association between distinct genotypes and clinical outcomes. METHODS: Using a PCR-RFLP and sequencing, HBV genotypes were determined in 136 patients with chronic type B hepatitis. RESULTS: The genotype C was detected in 131 patients (96.3%), and other 5 patients (3.7%) had genotype B. There were no significant differences in sex, age, disease duration, ALT level, HBeAg/anti-HBe status, or HBeAg loss between genotype B and C patients. CONCLUSIONS: These results suggest that almost all patients with chronic hepatitis B are infected with genotype C. Genotypes do not influence the outcome of chronic hepatitis B patients in Korea.