Significance of the minor i and t determinants of hepatitis B virus in hepatocellular carcinoma

Stored sera from asymptomatic hepatitis B virus (HBV) carriers and hepatitis B virus surface antigen-positive hepatocellular carcinoma (HCC) patients were tested for HBV subtypes, such as subtype determinants d, y, w, r and also antigenic determinants isoleucine (i) and threonine (t) by direct S gene nucleotide sequencing. Significant changes in minor i and t determinants in hepatocellular carcinoma patients with adr hepatitis B carriers were seen. The adr subtype with t determinant was present in 14/25 (56%) of HCC patients compared with only two of 28 (7%) in asymptomatic hepatitis B carriers ( P < 0.001). However, the adr subtype with i determinant was present in nine of 25 (36%) of the HCC patients and also present in 24/28 (86%) of asymptomatic carriers ( P < 0.001). No significant changes were seen with the adw subtypes. These results show that i and t minor determinant changes are more common with adr subtypes associated with HCC than with the adw subtype. Whether these subtle changes are pathologically relevant or only a polymorphism of hepatitis B genotypes will depend on subsequent follow-up studies.     

Molecular epidemiological study of hepatitis B virus in Thailand based on the analysis of pre-S and S genes.

Aims: This study was undertaken to determine the prevalence and characteristics of hepatitis B virus (HBV) genotypes, antigen subtypes, "a" determinant variants and pre-S gene mutations circulating on a large scale in Thailand. Methods: The sequences of the Pre-S1, Pre-S2 and S regions were determined in serum samples of 147 HBsAg and HBV DNA-positive subjects who had been enrolled from the nationwide seroepidemiological survey conducted on 6213 individuals in 2004. Results: The results showed that genotypes C, B and A accounted for 87.1%, 11.6% and 1.3%, respectively. The distribution of the HBV antigen subtypes was: adr (84.4%), adw (14.2%) and ayw (1.4%). Regarding the "a" determinant, 2/43 (4.65%) and 2/104 (1.92%) samples of vaccinated and non-vaccinated subjects, respectively, displayed mutations, all ofwhich were Thr126Asn. Sequencing analysis showed the pre-S mutations in 14 (9.5%) samples, with pre-S2 deletion as the most common mutant (4.1%) followed by pre-S2 start codon mutation (2.9%), both pre-S2 deletion and start codon mutation (2.0%), and pre-S1 deletion (0.7%). The pre-S mutations were associated with older age and higher mean serum HBsAg level. Conclusion: This study demonstrated that HBV genotype/subtype C/adr and B/adw were the predominant strains circulating in Thailand. The "a" determinant variants seemed to be uncommon, and might not be attributed to vaccine-induced mutation.     

Molecular epidemiology of hepatitis B virus in Indonesia

The S-gene sequences of hepatitis B virus (HBV) from 22 carriers in several islands of Indonesia were amplified by polymerase chain reaction, and XbaI-SpeI fragments corresponding to nucleotides 93-529 (437 base pairs) in the S gene were sequenced. The 22 sequences, along with the 5 reported sequences from Indonesia, were compared with each other, and with the corresponding sequences of 20 clones from other countries including China, France, Great Britain, Japan, Kenya, Papua New Guinea, Philippines, USA and USSR. When the 27 HBV DNA clones of various subtypes from Indonesia were classified by the homology in the nucleotide sequence into the five genotypes, twelve belonged to genotype B (subtype adw 7 and ayw 5), 13 to genotype C (adw 1, adr 10, ayr 1 and ar 1), and 2 to genotype D (ayw); none belonged to genotype A or E. Different subtypes of clones in the same genotype indicated that point mutations inducing d-to-y or w-to-r phenotypic changes would be common among Indonesian carriers. Comparison of the translation products of XbaI-SpeI fragments, now available for 47 HBV DNA clones of different genotypes (A 4; B 14; C 21; D 7; E 1), identified several amino acids characteristic to or influenced by the five genotypes as well as those highly conserved by clones of different genotypes.     

Hepatitis B viral genotypes: clinical relevance and molecular characteristics

Hepatitis B virus (HBV) infection is a global health problem and the clinical outcome of chronic HBV infection depends on the frequency and severity of hepatitis flares in the immune clearance phase. Currently, four subtypes and seven genotypes of HBV are identified and most have specific geographic distributions. The impact of HBV genotypes on the clinical outcome of chronic HBV infection has been partially clarified. In Taiwan, genotype C is associated with more severe liver disease and genotype B is associated with the development of hepatocellular carcinoma (HCC) in young non-cirrhotic patients. In contrast, genotype B has a relatively good prognosis in Japan and China and is rarely associated with the development of HCC. Similarly, genotype D is associated with more severe liver disease than genotype A in India and may predict occurrence of HCC in young patients. Although superinfection of HBV on top of hepatitis B carriers occurs in Taiwan, it is rarely associated with acute exacerbations. As to the response to antiviral treatment, genotypes C and D are associated with a lower response rate to interferon therapy compared with genotypes B and A. In addition, the subtype adw is reported to be associated with a higher risk of lamivudine resistance than ayw. In HBV subtype adw-infected HCC patients, genotype B responds better to embolization therapy and has a lower rate of HCC recurrence than genotype C. In summary, pathogenic and therapeutic differences do exist among HBV genotypes and determining the genotype in patients with chronic HBV infection would help gain further information for etiologic, clinical, virologic and anthropologic investigations. Further studies to clarify the molecular virological factors that contribute to these differences are awaited.     

泉州地区慢性乙型肝炎患者HBV基因型、基因亚型及血清型分布调查

目的调查泉州地区慢性乙型肝炎患者HBV基因型、基因亚型及血清型的分布。方法采用巢式PCR法对48例样本S基因扩增后进行测序,应用Neighbor Joining构建系统进化树并分析其基因型和基因亚型,应用Magnius和Norder法进行血清型分析。结果48例慢性乙型肝炎患者中,检测出B基因型35例（68.8%）,C型13例（31.2%）;B基因型中Ba亚型占97.0%,adw2血清型占93.9%;C基因型中C2亚型占93.3%,adrq+血清型占80.0%。结论泉州地区慢性乙型肝炎患者以B基因型为主,其次是C基因型;B基因型样本中,以Ba亚型和adw2血清型为主,C基因型样本中,以C2亚型和adrq+血清型为主。     

Subtypes of HBsAg in Eastern and South-Eastern Europe

Abstract. A total of 481 serum samples was collected from asymptomatic carriers of H B,Ag as well as some patients with acute and chronic hepatitis, type B. The sera were obtained mainly from blood banks in the following countries: Poland, Hungary, Romania, Bulgaria, Yugoslavia, and the European part of the Soviet Union. Asymptomatic carriers of HB_sAg from Poland and Hungary showed a preponderance of adw subtype over uyw subtype (Poland -80.7% adw , Hungary -72.2% adw). Carriers from the remaining countries showed the reverse situation: Bulgaria -71.5% ayw , Yugoslavia -79.0% ayw , Romania -82.8% ayw , Soviet Union -87.5% ayw. No individuals were found among these indigenous populations to have the adr or ayr subtypes but two carriers appeared to have the unusual subtype adyw.     

表面抗原和抗体双阳性慢性乙型肝炎病毒感染者病毒S基因的变异分析

目的 了解HBsAg和抗-HBs双阳性慢性HBV感染者的S基因变异情况.方法 分别对8例HBsAg和抗-HBs双阳性(实验组)及9例HBsAg阳性、抗-HBs阴性慢性HBV感染者(对照组)的S基因进行PCR扩增并测序,将测序结果进行对比分析.基因型和血清型分布比较、主要亲水区变异位点数比较采用Fisher'S精确检验,核苷酸和氨基酸序列的同源性比较采用t检验.结果 感染HBV的基因型分布:实验组为B型2例、C型6例,对照组为B型6例、C型3例,两组间差异无统计学意义(P>0.05);血清型分布:实验组为adw 2例、adr 5例、ayr 1例,对照组为adw 6例、adr 3例,两组间差异无统计学意义(P>0.05).实验组和对照组HBV前S1区的核苷酸替换率(2.29%比1.8%)和氨基酸替换率(2.66%比1.59%)差异无统计学意义(t值分别为1.56和1.39,P值均>0.05),前S2区的核苷酸替换率(1.74%比0.91%)差异有统计学意义(t=4.68,P<0.01),氨基酸替换率(3.18%比2.05%)差异无统计学意义(t=1.85,P>0.05);S区的核苷酸替换率(2.13%比0.81%)和氨基酸替换率(4.37%比1.52%)差异有统计学意义(t值分别为6.00和5.32,P值均<0.01).主要亲水区内外均存在氨基酸的替换,"a"决定簇变异相对较高(P<0.05).结论 HBsAg和抗-HBs双阳性慢性HBV感染者的S基因变异率相对较高.     

Distribution of hepatitis B virus genotypes among patients with chronic infection.

Hepatitis B virus (HBV) can be classified into at least eight genotypes, A-H. We evaluated the distribution HBV genotypes among patients with chronic infection. METHODS: We consecutively evaluated adult patients with chronic HBV infection from Salvador, Brazil. Patients were classified according to HBV infection chronic phases based on HBV-DNA levels and presence of serum HBV markers. HBV-DNA was qualitatively and quantitatively detected in serum by polymerised chain reaction (PCR). Isolates were genotyped by comparison of amino acid mutations and phylogenetic analysis. RESULTS: One-hundred and fourteen patients were evaluated. HBV-DNA was positive in 96 samples. HBV genotype was done in 76. Mean age was 36 +/- 11.3. In 61 of 76 cases subjects were classified as inactive HBsAg carriers. Their mean HBV serum level was 1760 copies/ml and 53 of 61 were infected with HBV genotype A, seven with HBV genotype F and one with genotype B. Twelve of the 76 patients had detectable hepatitis B e-antigen (HBeAg) in serum. Ten were infected with HBV genotype A and two with genotype F; most had increased alanine aminotransferase and high HBV-DNA levels. Three patients were in the immunotolerant phase, two were infected with HBV genotype A and one with genotype F. HBV subtyping showed subtypes adw2 and adw4. CONCLUSIONS: HBV genotype A adw2 and genotype F adw4 were the most prevalent isolates found. We could not find differences in genotype distribution according to HBV clinical phases and DNA levels. We did not detect HBV genotype D in contrast to a previous study in our center with acute hepatitis B. All inactive HBsAg carriers had low HBV-DNA levels.     

New Hepatitis B Surface Antigen Subtypes inside the ad Category

In addition to the 10 HBs Ag subtypes already described, 2 new subtypes were defined by using the q determinant. Exceptions to the rule generally accepted were found in that the q determinant was only lacking in HBs Ag/adw4. These exceptions occurred in adw and adr categories. These 2 new subtypes are adw q positive and adr q negative. Out of 98 HBs Ag/adw4 from silent carries and patients from different parts of the world, mainly from France (79), 6 were found q positive. 3 out of these 6 cases came from Montpellier (South of France) and another 3 from Germany. The 92 other cases were found q negative. Further studies will be necessary to better know the location of this new subtype adw4 q positive, but it seems to be present only in certain parts of Europe. Out of 86 HBs Ag/adr from silent carriers from Asia (58), Oceania (17), France (10, most of them contaminated in Asia) and Réunion (1), 10 were found q negative. All these 10 cases were detected in Oceania, 2 out of 2 in carriers from New Caledonia and 8 out of 13 from French Polynesia. The new subtype adr q negative seems localized in Melanesia and Polynesia and absent from Asia. These 2 new markers of hepatitis B virus will allow better epidemiological and geographical studies.     

Neutralization epitope responsible for the hepatitis B virus subtype-specific protection in chimpanzees

Neutralizing monoclonal antibody (BX-182) directed against the d determinant of hepatitis B virus (HBV) surface antigen protected chimpanzees from infection by HBV subtype adw but not by subtype ayw, as demonstrated by intravenously inoculating a mixture of the antibody with the respective subtype of the virus. To elucidate the mechanism underlying the subtype-specific protection, a combinatorial approach of screening random peptide phage libraries, bioinformatics, and structure analysis was used in this study to identify the neutralization epitope responsible for the observed protection. The epitope was mapped at the N terminus of the pre-S1 region of the hepatitis B surface antigen between residues 17 and 21, of which the residues Val-18/Pro-19 were critical for antibody binding. Alignment of amino acid sequences derived from diverse genetic variants of HBV revealed that the epitope was present in ad subtypes and in their corresponding genotypes A, B, C, F, and H. By contrast, this epitope was not found in a majority of ay subtypes or in genotypes D, E, and G, where the antigenic residues Val-18/Pro-19 within the epitope were replaced by Thr/Ser, Thr/Thr, or Ala/Ser, respectively, resulting in a drastic conformational change of the epitope. These data indicate that, by binding discriminately to the subtype "d" epitope in the pre-S1 region, neutralizing antibody BX-182 protects chimpanzees from HBV infection in a subtype-specific manner, suggesting a potential escape mechanism for HBV genetic variants.     

武汉地区儿童乙型肝炎患者病毒S基因"a"决定簇变异的研究

目的研究武汉地区儿童乙型肝炎患者中乙型肝炎病毒（HBV）S基因变异株的分子流行病学特征。方法通过流行病学调查筛选出30例经乙型肝炎疫苗免疫的儿童乙型肝炎患者及30例未免疫儿童乙型肝炎患者，利用聚合酶链反应（PCR）扩增HBV S基因片段，直接将PCR产物进行DNA序列测定。结果在60例儿童乙型肝炎患者中检测出55例adw血清亚型，其中8例HBV S基因发生氨基酸置换；直接测序检测的已免疫和未免疫儿童乙型肝炎患者S基因氨基酸置换频率分别为20．0％和6．7％，感染基因变异株的患儿发病年龄明显偏大，其疫苗免疫年限均较长。结论本地区流行的乙型肝炎病毒毒株主要为adw血清亚型；乙型肝炎疫苗具有免疫选择表面抗原基因变异株的作用；基因变异株病毒感染有随疫苗免疫年限延长而明显增加的趋势。     

adw亚型HBV突变体与ayw亚型辅助质粒之间相互包装的研究

目的探讨adw亚型HBV突变体与ayw亚型辅助质粒之间相互包装。方法构建C基因截短adw亚型HBV表达载体pHBV-ΔC。重组载体与ayw亚型辅助质粒pHBV3142共转染HepG2细胞。以与PGEm共转染为对照。用PCR检测细胞核内重组HBV载体cccDNA生成和培养上清中rcDNA的形成,用Native westernblot和Soutern blot检测重组HBV载体在辅助质粒pHBV3142辅助下的包装。结果在实验组细胞核内可检测到cccDNA、培养上清中可检测到rcDNA,对照组中无此结果。实验组Soutern blot见阳性信号而对照组无阳性信号。结论重组adw亚型HBV载体在辅助质粒ayw亚型pHBV3142辅助下能进行有效复制且有效完成病毒包装。     

135例乙型肝炎病毒感染者基因分型及其临床分布

目的研究乙型肝炎病毒（HBV）感染者中HBV基因分型及其临床分布情况。方法应用基因型和亚型特异性引物聚合酶链反应（PCR）法，对鲁西地区135例HBV感染者血清进行HBV基因型及亚型分型。结果未分型11例，已分型124例。其中C型111例（C2基因亚型87例、非C1／C2亚型24例）；B型11例，其中Ba型8例、Bj型3例；B／C混合型2例均为BaC2亚型混和感染。在肝硬化和重度慢性乙型肝炎中C型所占比例较高，分别为100％、88％；无症状携带者中B型所占比例较高为8．51％；HBV基因型分型与性别无关。结论鲁西地区HBV感染者以C基因型为主，其中C2亚型占优势。     

Genotype A2/adw2 Strain of Hepatitis B Virus in Turkey

Background and Aims

Previous studies have demonstrated the dominance of genotype D subtype ayw in patients with hepatitis B virus infection in Turkey. The aim of the present study is to report, for the first time, genotype A2 subtype adw2 of hepatitis B virus in a patient who is an inactive hepatitis B carrier in Turkey.

Materials and Methods

Hepatitis B virus DNA isolated from the serum sample was amplified by polymerase chain reaction. The polymerase gene segment of the hepatitis B virus was directly sequenced. A distance matrix/UPGMA comparison was used for phylogenetic analysis, and the genotype of the virus was identified accordingly. The subgenotype and subtype of hepatitis B virus were also detected.

Results

The genotyping of the patient revealed that the isolated hepatitis B virus was genotype A2/adw2.

Discussion

The subtype is inconsistent with the previous data from Turkey; specifically, the identification of the A2/adw2 subtype of the hepatitis B virus in an inactive carrier is the first such case in Turkey. This finding suggests that the transmission of another genotype besides genotype D subtype ayw of the hepatitis B virus is possible in Turkey.     

苏南地区乙型肝炎病毒S基因序列的多态性研究

目的:探讨乙型肝炎病毒(HBV)S基因序列的多态性,为研究HBV-S基因变异提供参照指导。方法:采用聚合酶链反应技术对81例乙型肝炎表面抗原阳性的HBV感染者的S基因进行扩增,再对扩增产物进行DNA测序,将结果与标准序列进行比较分析。结果:81价标本中,测得adr型38例,adw型43例,未发现有ayr及ayw型。38例adr型中氨基酸第121～125位点(AA121～125)、AA127～130、AA132、AA135～160高度保守,而AA126为异亮氨酸(Ile),也可为苏氨酸(Thr)或丝氨酸(Ser);AA131多为Thr,少数为天冬酰胺(Asn),1例为脯氨酸(Pro),AA133多为蛋氨酸,少数为Thr;AA134为苯丙氨酸,仅1例为精氨酸。43例adw型中,AA131均为Thr,而非Asn;AA126为Thr,也可为丙氨酸(Ala),少数为Ser;AA127多为Pro,少数为Thr;AA123为Thr,少数为Ala或Ile;AA141多为赖氨酸,少数为谷氨酸;AA133、AA140分别为Thr、Ile各1例。其他位点则高度保守。结论:HBV亚型分布具有地域性,苏南地区多以adw和adr型为主。HBV-S基因(“a”决定簇)序列存在多态性,其中adw亚型略为明显。     

Nucleotide sequence of a hepatitis B virus genome of subtype adw isolated from a Philippine: Comparison with the reported three genomes of the same subtype

The complete nucleotide sequence was determined for a hepatitis B virus genome of subtype adw (pFDW294) isolated and cloned from the plasma sample of a Philippino. The genome was 3221 base-pair long with a point mutation at the 1376th nucleotide that affected the coding capacity of the P and X genes. There was a wide range of sequence divergence among pFDW294 and the reported three genomes of the same subtype (1.1–9.9%), occurring more often in the pre-S region and the S gene than in the pre-C region and the C gene.     

Genotypic subtyping of the HIV-1 polymerase gene in 30 naåve patients from Thailand

To investigate the subtype classification of the circulating virus strains among infected Thai patients with human immunodeficiency virus type 1 (HIV-1). A random population of patients who were HIV-1 antibody positive after two independent screening assays was selected. HIV RNA from plasma samples was reverse-transcribed and amplified with specific primers that annealed to conserve regions of the HIV-1 pol gene. Amplified products were sequenced directly by using an automated sequencer. The sequencing products represent about 1.2 kb of the pol gene from each patient and they were phylogenetically analyzed and compared to the corresponding pol sequences of the published HIV-1 sequences of known genotypes. Genotype E was found in 25 of 30 patients (83.3%), and 5 patients (16.7%) were HIV-1 genotype B. The result confirmed that HIV-1 subtype E is still predominant in Thailand. Genotype B is found frequently, but there have been no examples of genotype A. In concordance with the serotypic assay, which was previously reported using the V3-peptide enzyme immunoassay (V3-PEIA), the genotypic assay of subtype E was high, at 80% and 83.3% in serotyping and genotyping, respectively. These findings of two subtypes with low heterogeneity indicate that Thailand may be a desirable site for evaluating candidate HIV-1 antiretroviral drugs and vaccines. The mixture of subtype E and B' strains also offers the opportunity to study phenotypic differences between the two subtypes.     

Prevalence and genotype distribution of hepatitis B virus among migrant workers in Lombok Island,Indonesia

Objective: To examine the potential risk of hepatitis B virus(HBV) spread in Indonesia by migrant workers, based on the molecular characteristics of HBV strains.Methods: Sera collected from migrant workers traveling to their destination countries(pre-migrant workers) and those returning to Indonesia(post-migrant workers) were screened for HBsAg by ELISA, followed by HBV DNA detection by PCR and(sub)genotype/subtype determination according to surface region and whole genome sequencing. Results: Of 87 pre-migrant workers, 15(17.24%) were HBsAgpositive, whereas 15(12.10%) of 124 post-migrant workers were HBs Ag seropositive. HBV genotype analysis based on the S region showed that HBV-B3/adw2 was predominant(96.15%, 25/26) whereas 3.85%(1/26) of isolates were HBV-C3/adrq+. Whole genome sequencing of selected strains and phylogenetic tree analysis identified subgenotype B7 in three samples previously categorized as subgenotype B3 based on S region analysis, supporting a recent argument that subgenotypes B5/B7/B8/B9 could be considered as a quasi-subgenotype of B3. Conclusions: A high prevalence of HBsAg carriers was detected among migrant workers from Lombok Island, with no significant difference in prevalence between before and after returning to Indonesia. All strains were classified into genotypes common in Indonesia, and the results suggested that migrant workers are not a risk factor for HBV transmission into Indonesia.     

Clustering of Different Subtypes of Hepatitis B Surface Antigen in Families of Patients with Chronic Liver Diseases

Clustering of hepatitis B surface antigen (HBsAg) with both subtypes adr and adw in three families of patients with chronic liver diseases or hepatocellular carcinoma was demonstrated in Taiwan where adw is the main subtype. The subtype in the children was similar to that in their mothers, suggesting maternal transmission. In all the family units clustered with different subtypes, the same pattern occurred, invariably with fathers carrying HBsAg/adr and the children carrying HBsAg/adw. The subtype difference clearly rules out the transmission of hepatitis B virus (HBV) from father. Horizontal infection with the locally dominant adw-subtyped HBV in the children of fathers carrying HBsAg/adr explains the discrepancy of the subtypes in these families. Clustering of two HBsAg-positive brothers with hepatocellular carcinoma in one of the families was found. That both adr-subtyped and adw-subtyped HBV are capable of inducing chronic active hepatitis in another family suggests that host factors are probably more important in determining the clinical course of HBV infection.     

Polymorphisms and resistance mutations of hepatitis C virus on sequences in the European hepatitis C virus database

AIM To evaluate the occurrence of resistant mutations in treatment-na?ve hepatitis C virus(HCV) sequences deposited in the European hepatitis C virus database(euH CVdb). METHODS The sequences were downloaded from the eu HCVdb(https://euhcvdb.ibcp.fr/eu HCVdb/). The search was performed for full-length NS3 protease, NS5 A and NS5 B polymerase sequences of HCV, separated by genotypes 1a, 1b, 2a, 2b and 3a, and resulted in 798 NS3, 708 NS5 A and 535 NS5 B sequences from HCV genotypes1a, 1b, 2a, 2b and 3a, after the exclusion of sequences containing errors and/or gaps or incomplete sequences, and sequences from patients previously treated with direct antiviral agents(DAA). The sequence alignment was performed with MEGA 6.06 MAC and the resulting protein sequences were then analyzed using the BioE dit 7.2.5. for mutations associated with resistance. Only positions that have been described as being associated with failure in treatment in in vivo studies, and/or as conferring a more than 2-fold change in replication in comparison to the wildtype reference strain in in vitro phenotypic assays were included in the analysis.RESULTS The Q80 K variant in the NS3 gene was the most prevalent mutation, being found in 44.66% of subtype 1a and 0.25% of subtype 1b. Other frequent mutations observed in more than 2% of the NS3 sequences were: I170V(3.21%) in genotype 1a, and Y56F(15.93%), V132I(23.28%) and I170V(65.20%) in genotype 1b. For the NS5 A, 2.21% of the genotype 1a sequences have the P58 S mutation, 5.95% of genotype 1b sequences have the R30 Q mutation, 15.79% of subtypes 2a sequences have the Q30 R mutation, 23.08% of subtype 2b sequences have a L31 M mutation, and in subtype 3a sequences, 23.08% have the M31 L resistant variants. For the NS5 B, the V321 L RAV was identified in 0.60% of genotype 1a and in 0.32% of genotype 1b sequences, and the N142 T variant was observed in 0.32% of subtype 1b sequences. The C316 Y, S556 G, D559 N RAV were identified in 0.33%, 7.82% and 0.32% of genotype 1b sequences, respectively, and were not observed in other genotypes.CONCLUSION HCV mutants resistant to DAAs are found in low frequency, nevertheless they could be selected and therapy could fail due resistance substitutions in HCV genome.