Identification of a hepatitis B virus S gene mutant in lamivudine-treated patients experiencing HBsAg seroclearance

BACKGROUND & AIMS: Seroclearance of hepatitis B virus (HBV) surface antigen (HBsAg) is a rare event in chronic hepatitis B patients receiving lamivudine therapy. It is generally believed to be a benevolent sign, implicating clearance of viremia. The aim of this study is to examine the authenticity of this dogma. METHODS: In a 5-year period, 11 patients treated with lamivudine experienced seroclearance of HBsAg. The clinical data were examined. The HBV S gene sequences derived from the patient's serum samples before and after seroclearance of HBsAg were analyzed. RESULTS: Serum HBV-DNA could be detected by nested polymerase chain reaction (PCR) in all 11 patients, by 1-step PCR in 8, and by Cobas Amplicor HBV-DNA test (>200 copies/mL) in 5. A mutation hot spot, P120A in the S gene, was identified in 6 of the 11 patients. Site-directed mutagenesis experiments indicated that the Ausria-II RIA test failed to detect this mutant. Decreased sensitivity of detection was also observed when other monoclonal antibodies were applied. CONCLUSIONS: Seroclearance of HBsAg during lamivudine therapy may not indicate viral clearance. Specifically, it may be caused by a point mutation in the S gene, which results in detection failure. In such patients, further verification and follow-up using a sensitive HBV-DNA test are advised.     

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.     

Sequence variation upstream of precore translation initiation codon reduces hepatitis B virus e antigen production

BACKGROUND & AIMS: Most South African hepatitis B virus strains harbor point mutations immediately upstream of the precore AUG codon. The aim of this study was to determine their effect on hepatitis B e antigen expression. METHODS: The hepatitis B virus DNA sequence around the precore region was determined from sera of 45 black South Africans. The South African mutations were introduced into hepatitis B virus dimers of the same genotype, and hepatitis B e antigen was quantified from culture medium of transfected HepG2 or Huh7 cells. RESULTS: The South African sequence changes were easily detectable in the acute, hepatitis B e antigen-positive phase of infection, suggesting that they were stable traits and were not selected by immune pressure. Triple mutations at the -5, -3, and -2 positions of the AUG codon severely impaired hepatitis B e antigen expression (P < 0.001). The frequent double mutation at the -5 and -2 positions moderately reduced hepatitis B e antigen levels (P < 0.001) to an extent comparable to that of the common core promoter mutations (1762(T)1764(A)). The presence of both South African and core promoter mutations diminished hepatitis B e antigen expression in an additive manner. It is interesting to note that the triple South African mutations enabled core protein translation from precore messenger RNA, which could rescue the replication defect of a hepatitis B virus genome with an ablated core gene. CONCLUSIONS: We have identified a novel class of hepatitis B e antigen variants with reduced hepatitis B e antigen translation by a ribosomal leaky scanning mechanism. Reduction in hepatitis B e antigen expression may contribute to accelerated seroconversion from hepatitis B e antigen to its antibody in black South Africans infected with hepatitis B virus very early in life.     

Kinetics and risk of de novo hepatitis B infection in HBsAg-negative patients undergoing cytotoxic chemotherapy

BACKGROUND & AIMS: De novo hepatitis B virus (HBV)-related hepatitis after chemotherapy results in high morbidity and mortality. We evaluate the clinical course of de novo HBV-related hepatitis after chemotherapy. METHODS: Two hundred forty-four consecutive hepatitis B surface antigen (HBsAg)-negative lymphoma patients treated with chemotherapy were followed up for a median of 12.4 (range, 0.1-65.0) months. Serially collected serum samples were analyzed for hepatitis, serum HBV DNA, and HBsAg seroreversion. RESULTS: Eight of the 244 patients (3.3%) developed de novo HBV-related hepatitis. A 100-fold increase in serum HBV DNA preceded de novo HBV-related hepatitis by a median of 18.5 (range, 12-28) weeks. All 8 patients had normal serum alanine aminotransaminase level when the 100-fold increase in serum HBV DNA occurred. Patients with de novo HBV-related hepatitis were more likely to have occult HBV infection before chemotherapy. Direct sequencing results showed that these 8 patients had de novo HBV-related hepatitis from reactivation of occult HBV infection. Three of the 8 patients with de novo HBV-related hepatitis compared with 6 of the 236 patients without de novo HBV-related hepatitis developed fulminant hepatic failure (37.5% vs 2.5%, respectively, P < .001). On multivariate Cox analysis, de novo HBV-related hepatitis was independently associated with a higher risk of fulminant hepatic failure (relative risk, 29.854; 95% confidence interval: 4.844-183.980; P < .001). CONCLUSIONS: Close surveillance for a 100-fold increase in HBV DNA is recommended for HBsAg-negative patients treated with chemotherapy so that early commencement of antiviral therapy can be initiated before the occurrence of de novo HBV-related hepatitis.     

Long-term therapy with adefovir dipivoxil for HBeAg-negative chronic hepatitis B for up to 5 years

BACKGROUND & AIMS: Treatment with adefovir dipivoxil for 48 weeks resulted in clinical improvement in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B that was lost when treatment was discontinued. We investigated the efficacy, safety, and resistance profile of adefovir dipivoxil treatment for up to 240 weeks. METHODS: HBeAg-negative patients were treated double blind with placebo or adefovir dipivoxil 10 mg once daily for 48 weeks, followed by adefovir dipivoxil from week 49 to 96. At week 97, 125 patients enrolled in a 144-week, open-label phase. Patients received adefovir dipivoxil for up to 192 or 240 weeks. RESULTS: Serum hepatitis B virus (HBV) DNA levels were less than 1000 copies per milliliter in 67% of patients, and alanine aminotransferase (ALT) levels normalized in 69% after 240 weeks. After 192 or 240 weeks of treatment, over 83% of patients had improvement in necroinflammation, and over 73% had improvement in fibrosis. Ishak fibrosis scores improved compared with baseline in 35%, 55%, and 71% of patients after 48, 192, and 240 weeks of adefovir dipivoxil, respectively. After 240 weeks, the cumulative probability of HBV polymerase mutations was 29%, but the cumulative probability of mutations with virologic resistance was 20% and of mutations, virologic resistance, and ALT elevations was 11%. Slight elevations in creatinine were confirmed in 4 (3%) patients. CONCLUSIONS: Treatment with adefovir dipivoxil for up to 240 weeks was well tolerated and produced significant, increasing improvement in hepatic fibrosis, durable suppression of HBV replication, normalization of liver enzymes, and delayed development of resistance.     

Long-term safety of lamivudine treatment in patients with chronic hepatitis B

BACKGROUND & AIMS: Data on the long-term safety of lamivudine are limited. The aim of this analysis was to determine the incidence of hepatitis flares, hepatic decompensation, and liver-disease-related (LDR) serious adverse events (SAE) during long-term lamivudine treatment. METHODS: We reviewed data on 998 patients with HBeAg-positive compensated chronic hepatitis B who received lamivudine for up to 6 years (median, 4 years) and 200 patients who received placebo for 1 year. RESULTS: Hepatitis flares occurred in 10% of the lamivudine-treated patients in year 1 and in 18%-21% in years 2-5. A temporal association between hepatitis flares and lamivudine-resistant mutations increased from 43% in year 1 to >80% in year 3. Ten hepatic decompensation events occurred in 8 (<1%) lamivudine-treated patients. Fifty-three (5%) lamivudine-treated patients experienced a total of 60 LDR SAEs. Four patients died, 2 from liver-related causes. The proportion of patients with a documented lamivudine-resistant mutation increased from 23% in year 1 to 65% in year 5. During each year of the study, patients with lamivudine-resistant mutations experienced significantly more hepatitis flares than patients without lamivudine-resistant mutations (P < 0.005). The occurrence of hepatic decompensation (0%-2%) and LDR SAEs (1%-10%) among patients with lamivudine resistance remained stable during the first 4 years with mutations and increased afterward to 6% (P = 0.03) and 20% (P = 0.009), respectively. CONCLUSIONS: This study demonstrated that lamivudine treatment for up to 6 years has an excellent safety profile in patients with HBeAg-positive compensated liver disease, but patients with long-standing lamivudine-resistant mutations may experience worsening liver disease.     

Clinical utility of a simple quantitative determination of hepatitis B e antigen

The titre of serum hepatitis B e antigen (HBeAg) was determined by using a simple quantitative system which is a slight modification of a commercially available enzyme immunoassay, and the relationship of serum HBeAg titre, hepatitis B virus (HBV)-associated DNA polymerase activity and HBV DNA level was evaluated. The HBeAg titre was found to have a significant correlation with DNA polymerase activity (r= 0.8153) and HBV DNA level (r= 0.8001). In 12 acute exacerbations of hepatitis in 10 patients with chronic type B hepatitis, these three parameters were found to be elevated either prior to or concurrent with the elevation of serum alanine aminotransferase, and the HBeAg titre peaked either simultaneously with or 1–4 weeks after the peaks of DNA polymerase activity and HBV DNA level, with average time lags of 1.00 weeks (s.d. = 1.29) and 1.08 weeks (s.d. = 1.25), respectively. Quantified HBeAg can be considered as a serum marker indicative of HBV replication, as is the case with DNA polymerase and HBV DNA. Furthermore, the HBeAg assay has the advantages of simplicity and low cost and it does not require special equipment. Therefore, quantification of HBeAg should be employed widely in clinical practice.     

Switching to peginterferon for chronic hepatitis B patients with hepatitis B e antigen seroconversion on entecavir – A prospective study

Nucleos(t)ide analogues (NA) are effective in suppressing hepatitis B virus (HBV) replication, but most patients require long‐term treatment. This study aimed to investigate switching to peginterferon as a strategy to stop NA. Hepatitis B e antigen (HBeAg)‐positive chronic hepatitis B patients who developed HBeAg seroconversion during NA treatment were studied. All patients received open‐label peginterferon alfa‐2a 180 μg/wk for 48 weeks, and NA was stopped at week 4 of peginterferon treatment. The primary endpoint was sustained response, which was defined as negative HBeAg, positive anti‐HBe and HBV DNA <2000 IU/mL at week 72. Other secondary endpoints including HBsAg loss at week 72 were also studied. Forty‐one patients treated with entecavir for 56 ± 23 months were recruited. Sustained response was achieved in 30 patients (73%, 95% confidence interval 58%‐84%). At week 72, 31 (76%) patients had HBeAg seroconversion, 56 (23%) patients had undetectable HBV DNA, 31 (76%) patients had normal ALT, and 6 patients (15%) had HBsAg loss. Baseline HBsAg level was the best predictor for both sustained response and HBsAg loss; the best HBsAg cut‐off for sustained response was <1500 IU/mL and that for HBsAg loss was <500 IU/mL by receiver operating characteristic curve analysis. Twenty‐two of 25 (88%) patients with baseline HBsAg <1500 IU/mL had sustained response. Five of 10 (50%) patients with baseline HBsAg <500 IU/mL developed HBsAg loss. Switching to peginterferon can be considered as a treatment option in NA‐treated patients with HBeAg seroconversion, particularly among those with lower HBsAg levels.     

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.