Acute Delta Hepatitis: Serological Diagnosis with Particular Reference to Hepatitis Delta Virus RNA

To evaluate serologic diagnosis of hepatitis delta virus, we tested HDV RNA in stored sera from 48 patients with acute delta hepatitis who were identified with anti-HD antibodies. Initial sera were positive for HDV RNA in 27 of 48 (56%) patients. In comparison, isolated IgM anti-HD was present in 18 (38%) patients, although IgM and IgG anti-HD were present concurrently in 16 (33%) additional patients. Overall, either HDV RNA or IgM anti-HD was present in 69% of the initial sera. The HDV infection was self-limiting in all except two patients who died of fulminant hepatitis and nine others in whom chronic delta hepatitis ensued. Patterns of HDV seropositivity during progression to chronicity induced variable persistence, disappearance or recrudescence of either HDV RNA or IgM and IgG anti-HD. Results of HDV RNA and IgM anti-HD tests were concordant in only 40-50% of instances. Our results indicate that serological testing for HDV RNA is direct and will demonstrate HDV replication in a large number of cases with acute delta hepatitis. Testing for IgM anti-HD could provide supplemental evidence for HDV infection. Sequential testing for these markers will facilitate assessment of the outcome of acute HDV infection.     

Treatment Options for Hepatitis Delta Virus Infection

The hepatitis D virus (HDV), the smallest virus known to infect man, causes the most severe form of chronic viral hepatitis, hepatitis delta. It is estimated that about 15 to 20 million people are suffering from chronic HDV infection. HDV is a defective satellite virus depending on the hepatitis B surface antigen (HBsAg) for transmission. Chronic hepatitis delta is associated with a rapid progression of liver fibrosis and a high prevalence of liver cirrhosis, even in younger patients. Immunization against hepatitis B virus (HBV) protects from HDV infection, but there is no specific vaccine against HDV available for HBsAg-positive individuals. Treatment options for hepatitis delta patients are limited. So far, only interferon-alpha has shown an antiviral efficacy against HDV. Recent trials showed sustained virological response rates concerning HDV in 25 %–30 % of patients treated with pegylated interferons. HDV is dominant over HBV in the majority of cases, but HBV DNA-positive subjects should be treated with HBV polymerase inhibitors. Combination therapy of pegylated interferon-alpha and adefovir showed a more pronounced HBsAg decline, but the exact role of combination therapies in hepatitis delta requires further investigation. Alternative future treatment strategies may include prenylation inhibitors and HBV entry inhibitors, which are in early clinical development.     

Perspectives for a Vaccine against Hepatitis Delta Virus

Hepatitis delta virus (HDV) causes severe hepatitis in carriers of hepatitis B virus (HBV). In ~90% of patients, HDV persists together with HBV and causes early development of cirrhosis and liver carcinoma. Worldwide ~15 million people are coinfected with HBV-HDV. Specific defects in the immune response causing persistence of the virus have not been identified. Several approaches to develop a vaccine to prevent superinfection in the preclinical model of the woodchuck have failed. Recent findings show that a DNA prime and viral vectors boost immunization regimen can induce a HDV specific CD8 T cell response and can prevent HDV infection in simultaneous infection of woodchuck hepatitis virus-HDV. The vaccine-induced specific CD8 T cell response is effective in preventing HDV replication and spread in the liver. However, the perspectives for a HDV vaccine against genotype-1 to prevent superinfection are much less promising. The T-cell response induced by the current DNA prime and viral vector boost immunization in the preclinical woodchuck model seems insufficient to prevent the spread of HDV in chronic HBV carriers. A more potent vaccine and repeated vaccinations are necessary to induce a HDV-specific T-cell response, which may prevent superinfection in HBsAg carriers.     

Delta Hepatitis: Forgotten,but Not Gone

Following the discovery of the hepatitis D virus (HDV) in the late 1970s and the development of assays to diagnose its infection, epidemiologic studies indicated that hepatitis D was endemic worldwide, with its prevalence varying in different countries. In most patients, chronic hepatitis D ran a severe and progressive course; the clinical profile of the disease was characterized by the presence of hepatitis B surface antigen (HBsAg) in blood, elevated alanine transaminase (ALT), an aggressive hepatitis on histology, and markers of HDV replication with absent markers of HBV replication in serum. With reduction of adult-acquired HBV infection in the past 20 years, the prevalence of HDV has also declined significantly in Europe and the industrialized world, because of reduction in the number of HBsAg-carriers necessary to HDV to persist. This has led to the less frequent diagnosis of hepatitis D. However, HDV infection has not disappeared. Europe still has a reservoir of the virus, sustained by two different pools of HDV-infected patients: the residual aging domestic pool that survived the brunt of the hepatitis D epidemic in the 1970s and 1980s, and the population of young patients with recent HDV infections migrating to Europe from areas where HDV remains endemic. The predominant clinical pattern is advanced cirrhosis in most domestic patients with long-standing disease, and a florid disease resembling the prototype pattern of HDV disease described in the 1980s, in the emigrants.     

丁型肝炎病毒载体携带核酶在小鼠体内抑制乙型肝炎病毒复制

目的:研究用丁型肝炎病毒(HDV)作为载体携带乙型肝炎病毒(HBV)特异性的锤头状核酶所构建的重组体,在细胞体系及转染动物模型中对HBV基因表达和复制的影响.方法:将HDV-核酶重组体和HBV的共表达质粒转染Huh-7细胞以分析HDV-核酶重组体对HBV基因表达的影响;用小鼠尾静脉快速注射法将共表达质粒转染到小鼠体内,检测重组体在动物体内对HBV基因表达和复制的抑制作用.结果:转染细胞中,重组体对HBsAg的抑制与HDV重组位点和核酶靶位都有关;水压法注射的质粒在小鼠肝内得到表达,与对照相比重组HDV-核酶可有效抑制在肝和血清中HBV的基因表达以及复制,与细胞中的结果一致.结论:此项体内实验为进一步构建治疗性重组HDV病毒,发现靶向性抗病毒基因治疗手段奠定基础.     

Current Concept in the Pathophysiology of Hepatitis Delta Infection

Hepatitis delta virus (HDV) is a unique human virus, showing similarities with plant viroids. Although impressive knowledge on virus structure and replication has been achieved, several questions like HBV/HDV interaction and post translational modifications of HD antigens remain to be answered. Potential targets for therapeutic strategies are now emerging. To date, eight major genotypes of the HDV have been identified. The HDV-1 is the prevailing genotype in Europe, but migration phenomena may change this profile. Immune response is likely to play an important role in the pathogenesis of HDV-induced liver disease; few data are available on T cells response either during infection and therapy. HDV usually suppresses HBV replication; recent studies show as viral dominances may change over time. Delta infection leads to severe liver disease, with different patterns of progression to liver fibrosis and decompensation. Beside the association between HDV/HBV and HCC is demonstrated a risk specifically related to HDV remains controversial.     

Clearance of Chronic HCV Infection During Acute Delta Hepatitis

Abstract   The course of chronic hepatitis C in acute HDV/HBV superinfection is unknown. Here, we report a patient with chronic hepatitis C who cleared HCV during acute self-limited hepatitis B/D superinfection. Recovery from HCV was associated with the appearance of a strong and multispecific HDV-specific memory CD4+ and CD8+ T cell response – but only weak HCV-specific CD4+ T cell responses. These data suggest that HCV can be cleared by bystander mechanisms during acute infections with other pathogens which may be considered in the development of immunotherapies for hepatitis C. *KD and SVP contributed equally.     

Interferon Alpha-2b Therapy in Chronic Hepatitis Delta

Background:

Approximately 5% of hepatitis B virus (HBV) carriers are coinfected with hepatitis D virus (HDV). HBV/HDV coinfection is a major cause of cirrhosis and end stage liver disease in chronic HBsAg carriers. The only approved therapy for chronic hepatitis delta is interferon alpha (IFN α) in either pegylated or conventional forms. Although higher doses and longer durations of IFN α therapy in HBV/HDV coinfected patients are currently applied, yet treatment response is low.

Objectives:

We aimed to determine the efficacy of IFN α-2b therapy in patients with HBV/HDV coinfection.

Patients and Methods:

In this cross sectional study, 20 HBsAg carriers with positive Anti-HDVAb and RT-PCR for HDV RNA were recruited and treated for three year duration with 5 million units (MU) of IFN α-2b, three times weekly or one year with 5 MU of IFN α-2b daily. Sustained virological response (SVR) was defined as a negative qualitative HDV RT-PCR, 6 months after treatment cessation.

Results:

Overall, 3 (15%) subjects achieved SVR, 10 cases (50%) relapsed after treatment cessation and 7 (35%) patients did not clear HDV during the treatment.

Conclusions:

HDV coinfection with HBV had very low response rate to high doses and long durations of IFN α-2b therapy.     

福建省部分地区丁型肝炎的研究

本研究应用酶联免疫(EIA)及核酸斑点杂交法对我省部分地区227例乙型肝炎患者检测了HDAg、抗-HD及HDVRNA。结果4例抗-HD阳性,1例HDAg与HDVRNA均为阳性,HDVM检出率为2.2％(5/227)。证实了丁型肝炎在福建省的存在,但感染率低,呈散在分布。各临床型乙肝患者HDVM检出率分别为:急性肝炎1.5％(1/67);慢性肝炎3％(4/135);HBsAg无症状携带者0(0/25)。慢性肝炎患者HDVM检出率明显高于HBsAg携带者,提示HDV感染与HBsAg阳性的慢性肝病密切相关。并发现本研究5例HDV感染者临床表现均为重叠感染,绝大多数患者HBV复制指标受到抑制。     

Prevalence of Hepatitis Delta Virus (HDV) Infection in Chronic Hepatitis B Patients with Unusual Clinical Pictures

Background

Probably 5% of the HBV carriers have HDV super infection. The risk of fulminant hepatitis, cirrhosis and hepatocellular carcinoma is higher in superinfection than the settings when HBV is alone.

Objectives

The aim of this study was to evaluate the prevalence of HDV in Iranian HBV isolates and to compare their clinical and virological pictures as well as their HDV genetic variations with other worldwide isolates.

Patients and Methods

81 carriers with positive results for HBsAg with upper limit ranges of ALT and low or undetectable levels of HBV viral load who did not respond to HBV therapy were selected. After RT amplification of HDV Delta antigen, direct sequencing and phylogenetic study were performed to explore the genotype(s) and nucleotide/amino acid variations.

Results

12 (14.8%) patients had positive results for both HDV RNA and anti-HDV. The mean ALT level was higher in HDV positive patients (75.9 U/ML) than HBV-mono-infected individuals; however, the mean HBV viral load was lower in coinfected patients than HBV-mono-infected patients. Phylogenetically, genotype I was the only detected genotype, and the most closely related isolates were of Turkish, Italian and Mongolian origin. Within the delta Ag, there were 326 nucleotide mutations, of which 111 and 215 were silent and missense, respectively. The total number of amino acid substitution was 148; most were located in known functional/epitopic domains. There was no correlation between the numbers of amino acid mutations, with clinical, virological status of the patients.

Conclusions

HDV should be suspected in HBV carriers with unusual clinical and virological pictures. Relatedness of Iranian HDV isolates to Italian and Turkish sequences proposed a common Caucasian origin for the distribution of HDV genotype I in this ethnic group.     

The Delta Agent in Acute and Chronic Hepatitis B Infection in Sweden

The occurrence of the delta (δ) agent was analyzed in 89 patients with acute hepatitis B infection during 1976-1979 in Gothenburg, Sweden, and in 46 patients (16 drug addicts) with chronic HBsAg-positive liver disease. Four of the patients with acute hepatitis B had transiently detectable anti-δ antibodies in serum. At least three of these four cases were associated with intravenous drug abuse. Eleven of the HBsAg carriers (24%) were anti-δ-positive, and all of them were drug addicts. One of the drug addicts transmitted hepatitis B infection without detectable anti-δ in serum to two other non-addicts via parenteral routes. Apparently, in Sweden today δ-infection is mostly restricted to drug addicts and seldom found in other groups of hepatitis B patients.     

A Rapid Point-of-Care Test for the Serodiagnosis of Hepatitis Delta Virus Infection

Hepatitis Delta virus (HDV) is a satellite of the Hepatitis B virus (HBV) and causes severe liver disease. The estimated prevalence of 15–20 million infected people worldwide may be underestimated as international diagnostic guidelines are not routinely followed. Possible reasons for this include the limited awareness among healthcare providers, the requirement for costly equipment and specialized training, and a lack of access to reliable tests in regions with poor medical infrastructure. In this study, we developed an HDV rapid test for the detection of antibodies against the hepatitis delta antigen (anti-HDV) in serum and plasma. The test is based on a novel recombinant large hepatitis delta antigen that can detect anti-HDV in a concentration-dependent manner with pan-genotypic activity across all known HDV genotypes. We evaluated the performance of this test on a cohort of 474 patient samples and found that it has a sensitivity of 94.6% (314/332) and a specificity of 100% (142/142) when compared to a diagnostic gold-standard ELISA. It also works robustly for a broad range of anti-HDV titers. We anticipate this novel HDV rapid test to be an important tool for epidemiological studies and clinical diagnostics, especially in regions that currently lack access to reliable HDV testing.     

Identification of Key Genes for Hepatitis Delta Virus-Related Hepatocellular Carcinoma by Bioinformatics Analysis

Background: It has been proposed that hepatitis delta virus (HDV) induces hepatic carcinogenesis by distinct molecular events compared with hepatocellular carcinoma (HCC) that is commonly induced by other hepatitis viruses. This study aimed to explore the underlying mechanism by identifying the key genes for HDV-HCC using bioinformatics analysis.Methods: The {"type":"entrez-geo","attrs":{"text":"GSE107170","term_id":"107170"}}GSE107170 dataset was downloaded and the differentially expressed genes (DEGs) were obtained by the online tool GEO2R. Gene otology (GO) functional analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using R packages. The protein-protein interaction (PPI) network was constructed by Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). Hub genes were selected by Cytoscape software according to degree algorithm. The hub genes were further validated in terms of expression and survival analysis based on public databases.Results: A total of 93 commonly upregulated genes and 36 commonly downregulated genes were found. The top 5 upregulated hub genes were TFRC, ACTR2, ARPC1A, ARPC3, and ARPC2. The top 5 downregulated hub genes were CTNNB1, CCND1, CDKN1B, CDK4, and CDKN1A. In the validation analysis, the expressions of ARPC1A, ARPC3, and CDK4 were promoted in general liver cancer samples. Higher expressions of ARPC2 and CDK4 and lower expressions of CDKN1A, CCND1, and CDKN1B were associated with worse prognosis in general HCC patients.Conclusion: The present study identifies a series of key genes that may be involved in the carcinogenesis of HDV-HCC and used as prognostic factors.     

Inspecting the Ribozyme Region of Hepatitis Delta Virus Genotype 1: Conservation and Variability

The hepatitis delta virus (HDV) genome has an autocatalytic region called the ribozyme, which is essential for viral replication. The aim of this study was to use next-generation sequencing (NGS) to analyze the ribozyme quasispecies (QS) in order to study its evolution and identify highly conserved regions potentially suitable for a gene-silencing strategy. HDV RNA was extracted from 2 longitudinal samples of chronic HDV patients and the ribozyme (nucleotide, nt 688–771) was analyzed using NGS. QS conservation, variability and genetic distance were analyzed. Mutations were identified by aligning sequences with their specific genotype consensus. The main relevant mutations were tested in vitro. The ribozyme was conserved overall, with a hyper-conserved region between nt 715–745. No difference in QS was observed over time. The most variable region was between nt 739–769. Thirteen mutations were observed, with three showing a higher frequency: T23C, T69C and C64 deletion. This last strongly reduced HDV replication by more than 1 log in vitro. HDV Ribozyme QS was generally highly conserved and was maintained during follow-up. The most conserved portion may be a valuable target for a gene-silencing strategy. The presence of the C64 deletion may strongly impair viral replication, as it is a potential mechanism of viral persistence.     

Determination of Hepatitis Delta Virus (HDV)-RNA in Asymptomatic Cases of HDV Infection

Objectives: To assess the frequency of hepatitis delta virus (HDV) viremia in asymptomatic cases of HDV infection and the clinical significance of the HDV viremia, we conducted a cross-sectional community-based study. Methods : Of 2207 examinees, 210 (9.5%) were found to be positive for hepatitis B surface antigen (HBsAg). Antibody to HDV was detected in 47 (22.4%) of the 210 examinees, and 43 of the 47 were further evaluated for serum HDV-RNA by polymerase chain reaction. Results : Twenty-one (48.8%) of the 43 had detectable levels of HDV-RNA in serum, and 22 (51.2%) were negative for serum HDV-RNA. The majority (61.9%) of the HDV-RNA-positive HBsAg carriers had high levels of serum ALT. In contrast, the frequency of an abnormally high level of serum ALT was only 9.1% in the HBsAg carriers positive for HDV antibody but negative for HDV-RNA and the frequency did not differ from that seen in the HBsAg-negative individuals. The semi-quantified HDV-RNA levels did not correlate with the serum ALT levels. Conclusion : Seropositivity of HDV-RNA was strongly associated with liver cell damage, even in asymptomatic cases. The absence of a detectable level of serum HDV-RNA might be related to previous HDV infection.