乙型肝炎病毒在丁型肝炎病毒包装中的作用机理研究

用含ＨＢＶ全基因和ＨＢＶ大、中、小分子表面蛋白基因的真核细胞表达质粒（ＣＭＶ－ＨＢＶ、ＣＭＶ－ＬＳ、ＣＭＶ－ＭＳ、ＣＭＶ－Ｓ）分别与含ＨＤＶ ｃＤＮＡ三聚体的重组质粒共转染ＣＨＯ细胞。转染后３天在上述４种转染细胞内及培养上清中均检出了ＨＤＶ ＲＮＡ和ＨＤＡｇ表明上述４种转染细胞的培养上清中均有ＨＤＶ病毒颗粒的包装和分泌。提示：ＨＤＶ病毒的包装可能仅需ＨＢＶ Ｓ 基因及其小分子表面蛋白的辅助。     

Co-expression of markers for hepatitis delta and hepatitis B viruses in human liver

Delta hepatitis (HDV) infection can only occur in the presence of hepatitis B (HBV) infection, as HDV requires a coat of HBV surface antigen (HBsAg) for assembly of complete virus. A number of studies have examined the variation of HBV markers in serum and liver during establishment of HDV infection, but none has systematically examined the relationship between the two viruses in individual hepatocytes. Liver biopsies from five patients with HDV/HBV infection were stained for HBsAg, HBV core antigen (HBcAg) and hepatitis D (delta) antigen (HDAg). Double immunostaining was performed with a combination of indirect immunoperoxidase and alkaline phosphatase/antialkaline phosphatase techniques. HDV and HBV antigens were expressed in all five liver biopsies. Co-localization of HBsAg was seen in up to 39% of HDAg positive cells, and HBcAg in up to 8% of HDAg positive cells. HBcAg was detectable in approximately 9% of HBsAg positive cells, and HBsAg in approximately 12% of HBcAg positive cells. HDV can replicate without HBV but ultimately requires HBV to produce complete virus and subsequently infect other cells. In this study the majority of HDV positive cells did not appear to contain HBV markers. This might suggest delta virus replication without assembly, or possibly sequential production/assembly of the virus.     

Prevalence of hepatitis B, C, and delta virus infections among children in Mongolia: progress in childhood immunization

Mongolia is highly endemic for hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) infections among apparently healthy adults. However, the age-specific prevalence of ongoing HBV, HCV, and HDV infections among children in Mongolia remains unknown. Therefore, samples obtained from a total of 655 apparently healthy children of 0.3-15 years of age (307 boys and 348 girls; age, mean +/- standard deviation [SD], 8.4 +/- 4.2 years) living in Mongolia, between October 2005 and January 2006, were tested for serological and molecular markers of HBV, HCV, and HDV infections. Although 88.7% of the 655 children studied were immunized against hepatitis B, 64 (9.8%) tested positive for hepatitis B surface antigen (HBsAg) and/or HBV DNA and 13 (2.0%) for HDV RNA. Twenty-seven children (4.1%) had detectable HCV RNA. Collectively, 82 (12.5%) were viremic for one or more of these viruses, including eight children with dual viremia of HBV/HCV and one child with triple HBV/HCV/HDV viremia. When children without anti-HBc, anti-HCV and anti-HDV IgG (n = 510) served as a control, a history of hospitalization was significantly associated with HBV viremia (P < 0.0001), anti-HBc positivity (P < 0.0001), and HCV viremia (P = 0.0001). HBsAg mutation was found in 18 (31.6%) of the 57 children with viremia, including those at amino acid position 126, 127, 129, 131, 134, 143 or 144. There were no significant differences in the frequency of HBsAg mutation in relation to age, sex, and hepatitis B vaccination status of the children, suggesting that HBsAg mutation plays a limited role in failure of vaccination in Mongolia.     

Hepatitis D virus

The hepatitis D virus (HDV) relies on the helper hepatitis B virus (HBV) for the provision of its envelope, which consists of hepatitis B surface antigen (HBsAg). The RNA genome of HDV is a circular rod-like structure due to its extensive intramolecular base-pairing. HDV-RNA has ribozyme activity which includes autocatalytic cleavage and self-ligation properties, essential in virus replication via the rolling circle mechanism. Replication of the RNA is thought to be effected by cellular RNA polymerase II. Hepatitis D antigen (HDAg) is the only protein encoded by HDV-RNA and its long and short forms have a regulatory role in the replication and morphogenesis of the virus. Superinfected HBV carriers who become chronically infected with HDV are at increased risk of developing cirrhosis. Attempts to treat such carriers with interferon have not been particularly successful. In recent years the epidemiology of HDV has changed primarily due to the impact of HBV vaccination in preventing an increase in the pool of susceptible individuals. © 1998 John Wiley & Sons, Ltd.     

High prevalence of hepatitis B,C and delta virus infections among blood donors in Mongolia

Summary. Serum samples obtained from 289 first-time and 114 repeat donors at the Blood Center of Mongolia (MBC) were tested for serological and molecular markers of hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) infections. Among the 403 blood donors, 33 (8.2%), 21 (5.2%), and 27 (6.7%) tested positive for hepatitis B surface antigen (HBsAg) and/or HBV DNA, HCV RNA, and HDV RNA, respectively. Collectively, 55 donors were viremic for one or more of these viruses, and included 54 first-time donors (18.7%) and 1 repeat donor (0.9%) (P < 0.0001). One discrepant case with HBsAg detectable only at MBC was negative for HBsAg, HBV DNA and anti-HBc in this study. Four donors who were HCV-viremic in this study were negative for anti-HCV by the MBC method. Further efforts to increase the sensitivity and specificity of the currently-used tests are urgently required in Mongolia. Three donors who were positive for anti-HBc and anti-HDV but negative for HBsAg, had both HBV DNA and HDV RNA. This suggests that introduction of a new anti-HDV serological test is useful for not only HDV screening but also HBV screening of anti-HBc-positive, HBsAg negative donors, considering a possibility of viral interference by coexisting HDV.     

Elimination of hepatitis delta virus infection after loss of hepatitis B surface antigen in patients with chronic delta hepatitis

The aim of this study was to evaluate whether patients with chronic hepatitis delta virus (HDV) infection treated with alpha interferon and subsequent loss of hepatitis B surface antigen (HBsAg) eliminate HDV. HDV RNA was detected in 26 of 28 patients with chronic delta hepatitis using the polymerase chain reaction. Seventeen patients in whom HDV RNA was detected were treated with alpha interferon; in 65%, HDV RNA remained detectable during treatment or reappeared after stopping therapy whereas in three patients HDV RNA remained absent (17.5%). HDV RNA became and remained undetectable in serum and liver of two of these three patients who lost HBsAg from serum and in one patient who was intermittently HBsAg negative during therapy. After loss of HBsAg, hepatitis B virus (HBV) DNA was still detectable in the liver, but not HBV RNA, indicating absent or very low HBV replication. Three patients were lost to follow up (17.5%). Two nontreated patients with chronic HDV infection also lost HBsAg during follow up; HDV RNA also became undetectable in their serum. Thus, HDV replication does not persist after the loss of HBsAg. Clearance of HBsAg may be a useful guide to when therapy can be stopped. © 1994 Wiley-Liss, Inc.     

Hepatitis B virus concentrations in serum determined by sensitive quantitative assays in patients with established chronic hepatitis delta virus infection.

To clarify the correlation between hepatitis B virus (HBV) DNA levels and serum alanine aminotransferase (ALT) levels in patients with established chronic hepatitis delta virus (HDV) infection, sensitive HBV quantitative assays were used for the study. Thirty-four consecutive patients with chronic liver disease who were positive for both hepatitis B surface antigen (HBsAg) and antibody to HDV (anti-HDV), including 19 patients with chronic hepatitis, 8 patients with liver cirrhosis and 7 patients with hepatocellular carcinoma. All were negative for hepatitis Be antigen (HBeAg) and positive for antibody to HBeAg. HBV DNA was detected in 25 (73.5%) of the 34 patients using real-time detection PCR, and the HBV DNA levels of these patients were significantly lower compared with HBeAg status and ALT level-matched patients with chronic liver disease positive for HBsAg but negative for anti-HDV. There was no correlation between serum HBV DNA and ALT levels among the 34 patients with chronic liver disease positive for anti-HDV. Whereas serum ALT levels in anti-HDV-positive HBsAg carriers with HDV RNA were significantly higher than those without HDV RNA. Liver damage in patients with established chronic HDV infection may be caused mainly by ongoing HDV infection not by HBV replication.     

Prevalence and clinical significance of hepatitis D virus co-infection in patients with chronic hepatitis B in Korea

Hepatitis D virus (HDV) infection can cause severe acute and chronic liver disease in patients infected with hepatitis B virus (HBV). Despite the significant decline in the global HDV infection, it remains a major health concern in some countries. This study aimed to investigate the prevalence and clinical features of HDV co-infection in patients with chronic HBV infection in Korea, where HBV infection is endemic. Nine hundred forty patients [median age, 48 (18-94) years; men, 64.5%] infected chronically with HBV were enrolled consecutively. All patients who were positive for hepatitis B surface antigen (HBsAg) for at least 6 months and were tested for anti-HDV. A portion of the HDV delta antigen was amplified, sequenced, and subjected to molecular and phylogenetic analysis using sera from the patients who were anti-HDV positive. Clinical features and virologic markers were evaluated. Inactive HBsAg carriers, chronic hepatitis B, cirrhosis and hepatocellular carcinoma accounted for 29.5%, 44.7%, 17.9%, and 8.0%, respectively. Only three patients were positive for anti-HDV, corresponding to a 0.32% positive rate. All patients who were positive for anti-HDV were inactive HBsAg carriers. HDV RNA could be amplified by PCR from the sera of two patients. Phylogenetic analysis showed that both carried HDV genotype 1. In conclusion, the prevalence of HDV infection is very low (0.32%) in Korea. All HDVs were genotype 1 and detected in inactive HBsAg carriers. Therefore, HDV co-infection may not have a significant clinical impact in Korean patients with chronic HBV infection.     

Prevalence of hepatitis B and hepatitis D coinfection in asymptomatic blood donors in Iran

Hepatitis delta virus (HDV) is a satellite virus that needs hepatitis B virus (HBV) surface antigen for amplification and transition. HDV appears in HBsAg carriers as acute coinfection and superinfection in patients with chronic hepatitis B. This coinfection leads to chronic hepatitis, cirrhosis, and liver carcinoma. The aim of this study was to detect the prevalence of coinfection and superinfection of HBVs and HDVs in blood donor individuals in Iran. Sera from 854 asymptomatic blood donors from the Bank of positive samples storage at the National Blood Transfusion Organization of Iran that were positive for hepatitis B surface antigen were analysed. The presence of antibody against HDV in blood donors was detected using ELISA followed by conventional PCR, seminested PCR and real‐time PCR to determine coinfection and/or superinfection. Restriction fragment length polymorphism was used for HDV genotyping. All 854 samples were HBsAg and anti‐HBc positive whereas only 18 (2%) of them were positive for anti‐HDV. Of the 854 samples, 154 (18%) were HBV‐DNA positive. HDV‐RNA was detected in 0.6% of the total samples by seminested PCR and real‐time PCR and the two PCR methods produced similar results. Moreover, 16.6% and 83.4% of anti‐HDV‐positive samples exhibited coinfection and superinfection with HBV, respectively. Genotype I of HDV was determined in positive samples.     

Acute and chronic hepatitis delta virus infection: Direct or indirect effect on hepatitis B virus replication?

In a large population of patients, chronic hepatitis delta virus (HDV) infection was usually associated with absence of hepatitis B virus (HBV) replication. However, acute HDV superinfection progressing to chronic HDV infection in two hepatitis B e antigen (HBeAg)-positive HBV carriers and coinfection in two other patients who progressed to chronic HBV (HBeAg-positive) and HDV infection was associated with continuing high-level HBV replication for several years. Thus HDV infection does not always inhibit HBV replication. The hypothesis that the different effects of HDV coinfection and superinfection on HBV replication may stem from variability in the capacity of the host to produce and respond to interferon is discussed.     

Molecular epidemiological and clinical aspects of hepatitis D virus in a unique triple hepatitis viruses (B,C, D) endemic community in Taiwan

The molecular epidemiological and clinical aspects of hepatitis D virus (HDV) in a unique HBV, HCV, and HDV triple virus endemic community in southern Taiwan were investigated. A total of 2,909 residents aged 45 or older were screened for hepatitis B surface antigen (HBsAg), anti-HCV antibody, and anti-HDV antibody (specifically for HBsAg-positive carriers). Factors that might be associated with HDV infection, viral nucleic acid detection, and genotyping of HBV, HCV, and HDV were investigated. The prevalence of HBsAg and anti-HCV were 12.6% (366/2,909) and 41.6% (1,227/2,909), respectively. For HBsAg carriers, 15.3% (56/366) were positive for anti-HDV assay. Living in a higher endemic district of HCV infection (odds ratio [OR] = 3.2; 95% confidence interval [CI] = 1.7-6.3), male gender (OR = 1.9; 95% CI = 1.1-3.6) and co-infection with HCV (OR = 1.8; 95% CI = 1.0-3.3) were significantly independent factors associated with HDV infection. The detection rate of HDV RNA among anti-HDV-positive patients was only 12.7% (7/55). The mean HBV titer of triple infection group was significantly lower than in the HBV/HDV co-infection group (2.23 vs 3.05 in log(10), copies/ml, P = 0.046). HCV RNA detection among the triple infection group showed 47.4% (9/19) viremia rate and viral loads of 579,121 IU/ml in median (16,803-1,551,190 IU/ml). The prevalent genotype of HBV was type B (23/25); HCV was 1b (7/9) and HDV was IIa/IIb (4/4). Only the presence of HCV RNA predicted the presence of elevated ALT significantly (OR = 25.0; 95% CI = 3.39-184.6). In conclusion, the geographical aggregation of HDV infection paralleled that of HCV infection in this community. HCV suppressed the replication of HBV among triple vital infection patients. HBV and HDV lapsed into a remission or nonreplicative phase in most cases, and HCV acted as a dominant factor in triple viral-infected individuals. Only the presence of HCV RNA was associated with elevated ALT values, but not HBV or HDV.     

Three heads are better than two: Hepatitis B core-related antigen as a new predictor of hepatitis B virus-related hepatocellular carcinoma

Patients with chronic hepatitis B virus (HBV) infection are at risk of developing hepatocellular carcinoma (HCC), and serum markers reflecting viral replication are potential predictors for HCC development. Besides the levels of serum HBV DNA and hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg) quantification is an emerging serological marker for viral replication. Unlike HBV DNA and HBsAg, HBcrAg is a covalently closed circular DNA-derived protein marker, consisting of hepatitis B e antigen (HBeAg), p22cr, and hepatitis B core antigen. In treatment-naïve HBV patients, higher HBcrAg levels are shown to be associated with an increased risk of HCC in several studies. More importantly, HBcrAg may complement HBV DNA level to predict HCC development. For example, an Asian treatment-naïve cohort study’s data showed that HBcrAg level of 4 log U/mL was effective to stratify HCC risk in HBeAg-negative patients with intermediate viral loads, who may not need antiviral therapy because of the low to moderate risk of HCC. In patients receiving prolonged nucleos(t)ide analogue with profound viral suppression, most data indicated that HBV DNA and HBsAg levels no longer serve as HCC predictors. However, several studies suggested on-treatment HBcrAg levels may remain as an HCC predictor. In summary, HBcrAg level can be a useful biomarker for treatment-naïve patients, but its value in on-treatment patients needs validation. The next challenge is how to combine HBcrAg with the other viral markers to construct a better HCC prediction model, optimizing the management of HBV patients.     

我国九个地区丁型肝炎病毒感染状况及其与乙型肝炎病毒复制指标关系的研究

对１５４５例各类乙型肝炎病毒表面抗原（ＨＢｓＡｇ）阳性肝病和无症状ＨＢｓＡｇ携带者的血清进行了乙型肝炎病毒（ＨＢＶ）与丁型肝炎病毒（ＨＤＶ）感染标记物的测定。结果表明，ＨＤＶ感染率为１３．０１％，其中ＨＤＡｇ和抗－ＨＤ阳性率分别为２．９１％和１０．０９％。而且在全国九个地区均有ＨＤＶ感染者存在，说明其分布是较为广泛的。同时还表现出，男性高于女性，慢性肝炎、重型肝炎及原发性肝癌高于急性肝炎和无症状ＨＢｓＡｇ携带者。提示ＨＢＶ与ＨＤＶ合并感染或重叠感染可能导致病情加重和感染的慢性化。本项研究结果还揭示，在ＨＢＶ与ＨＤＶ合并或重叠感染时，可能对ＨＢＶ的复制指标（ＨＢｅＡｇ·ＨＢＶＤＮＡ）有一定的抑制现象。     

Prevalence of Hepatitis D virus antibodies in Hepatitis B patients treated at tertiary care unit at Jabalpur Central India

Hepatitis Delta virus (HDV) infection amongst Hepatitis B virus (HBV) infected patients increases morbidity and mortality. The prevalence varies temporally and spatially. The present study aimed to evaluate the HDV prevalence in central India. Samples received from January 2018 to December 2019 were tested for viral hepatitis markers. Randomly picked 372 HBsAg positive samples were tested for the presence of HDV total antibodies using ELISA, of these 8 were found positive. This study for the first-time documents presence of HDV with 2.1% prevalence from central India. We recommend screening for better patient management and bringing down the disease burden.     

原位杂交法检测肝组织中丁型和乙型肝炎病毒核酸

利用国外引进的重组质粒获得纯化基因片段，分别以随机引物法和ＰＣＲ法制备地高辛素标记的ＨＢＶＤＮＡ探针和ＨＤＶｃＤＮＡ探针。用原位杂交法检测了石蜡包埋的肝组织切片ＢＶＤＮＡ和ＨＤＶＲＮＡ。４９例感染肝组织分为两组：丁肝组２３例；单纯乙肝组２６例，ＨＢＶＤＮＡ的检出率丁肝组（７８．２６％）与乙肝组（７６．９２％）无统计学差异；而ＨＤＶＮＡ的检出率丁肝组（６０．８７％）明显高于乙肝组（１５．３８％）。ＨＢＶＤＮＡ可见于受染肝细胞的胞核或胞浆内，而ＨＤＶＲＮＡ绝大部分见于肝细胞胞核。两种病毒核酸阳性细胞在肝组织中的分布特点大致相同：弥漫或散在地分布于肝小叶或假小叶内，或局灶性分布于小叶周边。ＨＤＶＲＮＡ阳性的肝组织都或多或少地同时存在ＨＢＶＤＮＡ。同一例肝组织中，ＨＢＶＤＮＡ阳性细胞从数量和颗粒密度上似略高于ＨＤＶＲＮＡ。将乙肝组和丁肝组两组病人肝内ＨＢ－ｓＡｇ、ＨＢｃＡｇ和ＨＢＶＤＮＡ及血清ＨＢｅＡｇ作了比较，各指标阳性率虽有差异，但均无统计学意义。因此，未发现ＨＤＶ感染对ＨＢＶ的复制有明显抑制作用。此结果对以往用血清学或免疫组化方法对ＨＤＶ的研究有所补充和深入，亦可为研究其它类型病毒性肝炎之间的重叠感染所借鉴。     

Hepatitis delta virus: A fascinating and neglected pathogen

Hepatitis delta virus(HDV) is the etiologic agent of the most severe form of virus hepatitis in humans. Sharing some structural and functional properties with plant viroids, the HDV RNA contains a single open reading frame coding for the only virus protein, the Delta antigen. A number of unique features, including ribozyme activity, RNA editing, rolling-circle RNA replication, and redirection for a RNA template of host DNA-dependent RNA polymerase Ⅱ, make this small pathogen an excellent model to study virus-cell interactions and RNA biology. Treatment options for chronic hepatitis Delta are scarce and ineffective. The disease burden is perhaps largely underestimated making the search for new, specific drugs, targets, and treatment strategies an important public health challenge. In this review we address the main features of virus structure, replication, and interaction with the host. Virus pathogenicity and current treatment options are discussed in the light of recent developments.     

Hepatitis delta virus

Hepatitis delta virus (HDV) is a sub-viral agent that is dependent for its life cycle on hepatitis B virus (HBV). The help it obtains from HBV is limited to the sharing of envelope proteins. These proteins are needed to facilitate the assembly of the HDV genome into new virus particles, and in turn, to allow the attachment and entry of HDV into new host cells. In other respects, the replication of the small single-stranded circular RNA genome of HDV is independent of HBV. HDV genome replication produces two forms of a RNA-binding protein known as the long and small delta antigens (Ag). All other proteins needed for HDV genome replication, especially the RNA-directed RNA polymerase activity, are provided by the host cell. This mini-review article is a mixture of personal perspective and speculations about the future of HDV research. It starts with a brief overview of HDV and its replication, notes some of the major unresolved questions, and directs the interested reader to more detailed reviews.