A paucity of liver disease in Canadian Inuit with chronic hepatitis B virus,subgenotype B6 infection

Clinical observations suggest that chronic hepatitis B virus (HBV) infections in the Canadian Inuit are less often associated with serious adverse outcomes than has been described in other HBV‐infected patient populations. The aim of this study was to document the clinical and biochemical features, liver‐related morbidity and all‐cause mortality in Canadian Inuit with chronic HBV infections. Administrative databases were reviewed for individuals identified as hepatitis B surface antigen (HBsAg) positive during a 1983–85 seroepidemiological survey of viral hepatitis in Baffin Island, Canada. An equal number of age‐ and gender‐matched HBsAg‐negative individuals from the same communities served as controls. Baseline HBV viral loads, genotypes and specific mutations were compared in HBsAg‐positive survivors and nonsurvivors. A subset of surviving HBsAg‐positive carriers were reassessed 25–30 years following their initial diagnosis for evidence of advanced liver disease and changes to their serological/virological findings. One hundred and forty four HBsAg‐positive individuals were identified. All were Canadian Inuit. The mean age at diagnosis was 38 ± 17 years and 69 (61%) were male. Median follow‐up was 23 years (range: 2–28 years). Viral quantitation from stored sera could be performed in 70 infected individuals. The median viral load was 4.3 log 10 IU/ml (range: 2.3–8.8 log 10 IU/ml), and all were genotype B, subgenotype B6. Liver biochemistry, morbidity and all‐cause mortality rates were similar in HBsAg‐positive carriers and controls. Following multivariate analyses, only age at diagnosis predicted mortality in HBsAg carriers. In a subset of 30 HBsAg‐positive survivors who underwent follow‐up assessments, clinical, biochemical and radiological examinations of the liver were essentially normal. 23/30 (77%) remained HBsAg positive and 17/19 (90%) HBV‐DNA positive. The genotype and prevalence of genomic mutations in this cohort remained largely unchanged, but quantifiable viral loads were significantly lower (P < 0.003). The results of this study suggest that chronic HBV infections in the Canadian Inuit are infrequently associated with serious adverse outcomes. Whether this finding reflects unique features of the host, presence or absence of external factors that influence the course of HBV and/or intrinsic properties of the HBV B6 subgenotype remains to be determined.     

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.     

Chronic hepatitis B virus (HBV) infection in children: 25 years' experience

Whereas e‐seroconversion represents the loss of hepatitis B e‐antigen (HBeAg) followed by gain of antibody to HBeAg (anti‐HBe), ‘inactive chronic infection’ extends this concept to include e‐seroconversion with decreased serum viral load and biochemical remission. These events must be well‐characterized before treatment outcomes can be evaluated. We examined the rates of e‐seroconversion and achievement of inactive chronic infection among children with chronic HBV infection. Children who were HBsAg positive >6 months were identified retrospectively between 1983 and 2008 from the Hospital for Sick Children Liver Clinic. Inactive chronic infection was defined as loss of HBeAg, serum ALT ≤40 IU/mL, and HBV DNA <10⁶ IU/mL. Both e‐seroconversion and achievement of inactive chronic infection were characterized using survival analysis. The effect of transmission route, treatment, age at diagnosis, ethnicity, gender and baseline ALT on these rates was evaluated with univariate and multiple regression. Of 252 HBeAg‐positive cases, 59.9% had HBV‐infected mothers, 77% were Asian, and 33 received interferon‐α. Untreated children were younger at last follow‐up (mean 14.5 vs 17.6 years), had lower ALT (median 60 vs 116 IU/mL) and had shorter follow‐up (6.6 vs 9.1 years, all P < 0.002) compared to treated children. Crude e‐seroconversion rate was 41.7% over 0.5–19.1 years of follow‐up, and this was not affected by transmission route (P = 0.93), gender (P = 0.62) nor treatment (P = 0.08). 49% achieved inactive chronic infection by age 19 years. Being non‐Asian, age at diagnosis<3 years, and ALT ≥40 IU/mL were associated with a higher rate of e‐seroconversion and achieving inactive chronic infection (P < 0.0001). Almost 50% of children achieved inactive chronic infection by early adulthood.     

The natural history of chronic hepatitis B

Summary.  The natural history of chronic hepatitis B is dependent on the age of acquiring the hepatitis B infection. Those who are infected at adolescence or adulthood (including most of the Caucasians) tend to have stable disease after hepatitis B e antigen seroconversion with normal serum alanine aminotransaminase (ALT) and hepatitis B virus (HBV) DNA levels <10⁵ copies/mL (20 000 IU/mL). In contrast, those who are infected at birth or early childhood (including the majority of the world's hepatitis B carriers, i.e. Asians) have a prolonged immune tolerance phase followed by a prolonged immune clearance phase. A proportion of these patients have progressive disease after HBeAg seroconversion with HBV DNA <10⁴ copies/mL (<2000 IU/mL) and ALT between 0.5 and 2× upper limit of normal. Core promoter mutations may play a part in the development of cirrhosis-related complications. However, continuing viral replication, even at a relatively low level of <10⁴ copies/mL (<2000 IU/mL), is probably the most important factor for the development of complications.     

Different mutation rates in the basal core promoter and precore regions between hepatitis B virus subgenotype F1b clusters

Hepatitis B virus (HBV) is the main etiological agent of hepatocellular carcinoma (HCC) worldwide. It has been classified into nine genotypes and several subgenotypes, with uneven global distribution. There is growing evidence that the viral genotype influences the course and outcome of chronic hepatitis B infection. Two evolutionarily different clusters of the subgenotype F1b, called basal and cosmopolitan, have been described. The two clusters have constrained geographical distribution, with the particular feature that the basal cluster is present in regions of high HCC incidence, while the Cosmopolitan cluster is found in regions of low HCC incidence. The BCP/pC region was sequenced in 68 cases chronically infected with the F1b subgenotype to determine if there was a differential pattern of pathogenic-associated mutations between both clusters. Twenty-two of the 68 cases belonged to the subgenotype F1b basal cluster and 46 to the cosmopolitan cluster. Among the HBeAg-negative patients the A1762T/G1764A and G1896A mutations were more frequently found in the basal samples (85.7 and 92.9%) compared to the cosmopolitan ones (50 and 18.2%). Interestingly, no HBeAg loss-associated mutations were observed in 7.1 and 36.4% of the basal and cosmopolitan cases, respectively. The different rate of mutations associated with a more severe course of chronic hepatitis in the basal cluster would support the difference in the HCC incidence rate in the geographical regions where the basal cluster is restricted.     

Hepatitis B virus subgenotype A1 predominates in liver disease patients from Kerala,India

AIM:To molecularly characterize hepatitis B virus(HBV)isolates from Kerala and to relate them to the clinical manifestation of infection.METHODS:Sera and clinical data were collected from91 patients diagnosed with chronic HBV infection and HBV-related hepatocellular carcinoma(HCC).HBV from44 HCC,22 cirrhotic and 25 chronic hepatitis patients were genotyped by sequencing of the complete S region or by restriction fragment length polymorphism assays.The basic core promoter/precore region was sequenced.The complete surface DNA sequences were assembled and aligned manually,and then compared with the sequences of HBV of genotypes(A-J)from GenBank.The evolutionary history was inferred using the Neighbor-Joining method and the evolutionary distances computed using the Kimura 2-parameter method.Bootstrapping was performed using 1000 replicates.The TaqMan BS-1 probe was used to quantify HBV DNA at a lower detection limit of approximately20 IU/mL.Continuous variables were compared using an independent Student’s t test.Theχ2test or Fisher’s exact test was used to compare categorical variables.The differences were considered statistically significant at P<0.05.RESULTS:Irrespective of disease status,the predominant genotype was A(72%);95%belonging to subgenotype A1,followed by genotypes D(27%)and C(1%).HCC patients infected with subgenotype A1were significantly younger than those infected with D.Mutation A1762T/G1764A was significantly associated with HCC in both genotypes A and D.Mutation G1862T was more frequent in subgenotype A1(P<0.0001),and in combination with A1762T/G1764A,it was significantly associated with HBV from HCC patients.Mutation C1766T/T1768A was significantly associated with genotype A(P=0.05)and HCC(P=0.03).The preS2start codon M1T/I mutation was unique to genotype A strains(15.6%)from all disease groups and occurred at a higher frequency in isolates from HCC patients(P=0.076).A higher frequency of preS deletion mutants(33.3%)was observed in genotype A from HCC compared with non-HCC patients,but     

血清乙型肝炎病毒前S1抗原对判定HBV DNA复制的临床价值

目的通过分析HBV Pre-S1抗原与HBeAg和HBV DNA的相关性,以探讨其在诊断HBV复制的临床价值。方法采用ELISA法、荧光定量PCR法检测450例HBsAg阳性及50例健康对照血清标本的HBV Pre-S1抗原、血清HBV标志物、HBV DNA及肝功能。结果在450例HBsAg阳性血清中,HBeAg、Pre-S1抗原和HBV DNA阳性率分别为40.0%、57.3%和61.6%;Pre-S1抗原、HBV DNA阳性率在HBeAg阴性与阳性组间差异有统计学意义（x2=84.2,x2=110.7,P〈0.01）;PreS1抗原与HBeAg和HBV DNA均存在相关性（x2=86.5x,2=272.1,P〈0.01）;Pre-S1抗原阳性组AST、ALT、TBl、γ-GT均高于阴性组（P〈0.01）;当HBV DNA拷贝数的对数值〉2.7lgcopies/ml时,Pre-S1抗原诊断HBV复制的敏感度为87.7%,特异度为91.3%,准确性为89.1%,阳性预测值为94.2%,阳性似然比为10.1,优势比为75.3,而HbeAg则分别为59.2%、90.8%、71.3%、91.1%、6.43和14.2。结论 HBV Pre-S1抗原与HBeAg和HBV DNA均有较好的相关性,可作为一项新的病毒复制的指标。     

e抗原阴性患者抗病毒治疗中乙型肝炎前S1抗原的变化

目的 通过对乙型肝炎患者前S1抗原(Pre-S1抗原)检测,了解乙肝病毒(HBV)的复制情况,并用于指导e抗原(HBeAg)阴性的患者进行抗病毒治疗.方法 在我院2004年4月～2006年5月门诊及住院慢性乙肝患者中,采用外周血进行肝功能、Pre-S1抗原、乙肝五项等检查,其Pre-S1抗原阳性、HBeAg阴性的29例患者,采用α-干扰素抗病毒治疗6月,分析Pre-S1抗原在抗病毒治疗前的血清学变化.结果 经α-干扰素抗病毒治疗6月后,患者临床症状基本消失,Pre-S1抗原阴转26例,肝功能基本恢复正常,ALT 52±17 U/L.结论 HBeAg阴性而Pre-S1抗原阳性的患者,在体内存在病毒复制,同时存在肝功能的损害,仍需要抗病毒治疗.     

Molecular mechanisms of hepatocarcinogenesis in chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is a major cause of hepatocellular carcinoma (HCC) and chronic liver disease worldwide. Recent developments and advances in HCV replication systems in vitro and in vivo, transgenic animal models, and gene expression profiling approaches have provided novel insights into the mechanisms of HCV replication. They have also helped elucidate host cellular responses, including activated/inactivated signaling pathways, and the relationship between innate immune responses by HCV infection and host genetic traits. However, the mechanisms of hepatocyte malignant transformation induced by HCV infection are still largely unclear, most likely due to the heterogeneity of molecular paths leading to HCC development in each individual. In this review, we summarize recent advances in knowledge about the mechanisms of hepatocarcinogenesis induced by HCV infection.     

Assessment of chronic hepatitis B: the importance of hepatitis B virus DNA testing

Background: Chronic hepatitis B (CHB) has an estimated prevalence of 90 000 to 160 000 in Australia. Cirrhosis and hepatocellular carcinoma are important complications of CHB and appropriate evaluation of hepatitis B surface antigen (HBsAg)‐positive individuals is vital to identify treatment candidates. Methods: A review of the database of a tertiary hospital was performed and 348 HBsAg‐positive individuals with baseline demographic, virological, serological and biochemical variables were identified and evaluated cross‐sectionally. A small subgroup of hepatitis B e antigen (HBeAg)‐negative patients with normal alanine aminotransferase (ALT) at baseline were identified and followed longitudinally. Results: 175/348 (50%) of patients were in the HBeAg‐negative, chronic hepatitis phase of disease, 22% in the HBeAg‐positive immune clearance and 6% in the immune tolerant phases. HBeAg‐negative patients were older and more likely to be male than HBeAg‐positive patients. The correlation between hepatitis B virus (HBV) DNA and ALT levels was examined. ALT and HBV DNA levels showed no correlation in HBeAg‐positive CHB and only a weak correlation in HBeAg‐negative patients. Furthermore, 35% of HBeAg‐negative patients with detectable HBV DNA had a normal ALT. Conversely 38% of HBeAg‐negative patients with no detectable HBV DNA had an elevated ALT. A persistently normal ALT over 24 months was seen in five of nine HBeAg‐negative patients with normal initial ALT and detectable HBV DNA. Conclusion: Appropriate evaluation of HBeAg‐negative CHB must include HBV DNA because the ALT is not a reliable guide to underlying viral replication.     

慢性HBV携带者发展为肝细胞癌1例报告

正1病例资料患者男性,40岁,于1998年体检发现HBs Ag阳性,无乙型肝炎家族史,不饮酒,无其他疾病史,未行保肝及抗病毒治疗。2004年8月来本院门诊首次就诊,查血常规、凝血常规、肝功能均正常;HBs Ag、HBe Ag、抗-HBc阳性,HBV DNA定量6.3×105IU/ml,甲胎蛋白(AFP)3.65 ng/ml,腹部超声提示肝血管瘤可能性大,胆囊     

A pediatric case of hepatitis B virus subgenotype A2 in Japan

Hepatitis B virus (HBV) has been classified into 10 major genotypes, and HBV genotypes C and B are found in the majority of Japanese patients. However, the prevalence of genotype A has been increasing in patients with chronic or acute hepatitis. Here we report a pediatric case of HBV subgenotype A2. A 2-year-old girl was referred to our hospital for liver damage caused by HBV infection. During the pregnancy, her father had developed acute sporadic hepatitis B. The child was born without any complications. She did not receive HBV vaccination at birth because her mother was negative for HBs antigen at the pre-delivery screening; however, her mother developed acute hepatitis B 2 months after delivery. At that time, HBs antigen was detected in the current patient. Phylogenetic full-length sequence analysis revealed HBV subgenotype A2. HBV sequencing was not performed for her parents; therefore, the intrafamilial transmission routes in these cases are unclear, although the authors speculate that, for the current patient, mother-to-child transmission may have occurred. This report illustrates the pitfalls of the selective vaccination strategy in Japan for preventing HBV infection. Universal vaccination to prevent HBV infection might be useful in Japan.     

A novel hepatitis B virus subgenotype D10 circulating in Ethiopia

Hepatitis B virus (HBV) is genetically highly divergent and classified in ten genotypes and forty subgenotypes in distinct ethno‐geographic populations worldwide. Ethiopia is a country with high HBV prevalence; however, little is known about the genetic variability of HBV strains that circulate. Here, we characterize the complete genome of 29 HBV strains originating from five Ethiopian regions, by 454 deep sequencing and Sanger sequencing. Phylogenetically, ten strains were classified as genotype A1 and nineteen as genotype D. Fifteen genotype D strains, provisionally named subgenotype D10, showed a novel distinct cluster supported by high bootstrap value and >4% nucleotide divergence from other known subgenotypes. In addition, the novel D10 strains harboured nine unique amino acid signatures in the surface, polymerase and X genes. Seventy‐two per cent of the genotype D strains had the precore premature stop codon G1896A. In addition, 63% genotype A and 33% genotype D strains had the basal core promoter mutations, A1762T/G1764A. Furthermore, four pre‐S deletion variants and two recombinants were identified in this study. In conclusion, we identified a novel HBV subgenotype D10 circulating in Ethiopia, underlining the high genetic variability of HBV strains in Africa.     

阿德福韦酯治疗HBeAg阳性慢性乙型肝炎101例临床观察

目的观察阿德福韦酯治疗HBeAg阳性慢性乙型肝炎和拉米夫定治疗无效的慢性乙型肝炎患者,单药连续144周治疗,停药后监测96周疗效和药物安全性。方法初始治疗69例,拉米夫定治疗无效再治疗32例共101例,采用单药阿德福韦酯(ADV)10mg,每日1次口服,连续治疗144周,疗程结束继续监测到240周。结果阿德福韦酯初治组和复治组经144周连续治疗和停药后监测至240周血清ALT累积复常率分别为91.3%和90.6%,血清HBV DNA转阴率分别为88.4%和84.3%,HBeAg转阴率分别为34.7%和28.1%,HBeAg/HB-eAb血清转换率分别为55.0%和53.1%,HBsAg/HBsAb血清学转换均在停药后不同时间段发生,初治组为7.2%,复治组为6.3%。经144周连续治疗和停药后随访期间血、尿常规和肾功能,均无与治疗相关的异常发现。结论阿德福韦酯单药10mg每日1次口服治疗HBeAg阳性慢性乙型肝炎患者,有显著抑制HBV DNA复制,对拉米夫定治疗无效患者,可获得同样疗效,长期服药无明显耐药性,安全性好。     

Activation of fibronectin gene expression by hepatitis B virus x antigen

The development of fibrosis and cirrhosis during chronic hepatitis B virus (HBV) infection correlates with the persistent expression of HBV x antigen (HBxAg), which acts in part, by stimulating selected signal transduction pathways, including nuclear factor kappa B (NF-kappa B). To identify NF-kappa B responsive genes that are differentially expressed in HBxAg-positive cells, HepG2 cells were stably transfected with HBxAg, and then with pZeoSV2 or pZeoSV2-I kappa B alpha. When RNAs from each culture were compared by PCR-select cDNA subtraction, fibronectin (FN) mRNA was shown to be strongly down-regulated by I kappa B alpha. Up-regulated expression of FN and co-expression between FN and HBxAg were observed in liver sections from HBV carriers that were stained for HBxAg and analysed for FN mRNA by in situ hybridization (ISH). In liver cell cultures, HBxAg increased the levels of FN mRNA and protein. This was because of the HBxAg-mediated trans-activation of the FN promoter, which was NF-kappa B-dependent. HBxAg also antagonized the repression of the FN promoter by the tumour suppressor, p53. Hence, the FN gene may be a natural target for HBxAg trans-activation, perhaps through activation of NF-kappa B and inactivation of p53, thereby contributing to the accumulation of FN in the liver over the course of chronic HBV infection.