Hepatitis B virus DNA sequences in lymphoid cells from patients with AIDS and AIDS-related complex

The role of the hepatitis B virus genome and its integration in the hepatocellular carcinoma

The integration of Hepatitis B Virus (HBV) is now known to be closely associated with the occurrence of liver cancer and can impact the functionality of liver cells through multiple dimensions. However, despite the detailed understanding of the characteristics of HBV integration and the mechanisms involved, the subsequent effects on cellular function are still poorly understood in current research. This study first systematically discusses the relationship between HBV integration and the occurrence of liver cancer, and then analyzes the status of the viral genome produced by HBV replication, highlighting the close relationship and structure between double-stranded linear (DSL)-HBV DNA and the occurrence of viral integration. The integration of DSL-HBV DNA leads to a certain preference for HBV integration itself. Additionally, exploration of HBV integration hotspots reveals obvious hotspot areas of HBV integration on the human genome. Virus integration in these hotspot areas is often associated with the occurrence and development of liver cancer, and it has been determined that HBV integration can promote the occurrence of cancer by inducing genome instability and other aspects. Furthermore, a comprehensive study of viral integration explored the mechanisms of viral integration and the internal integration mode, discovering that HBV integration may form extrachromosomal DNA (ecDNA), which exists outside the chromosome and can integrate into the chromosome under certain conditions. The prospect of HBV integration as a biomarker was also probed, with the expectation that combining HBV integration research with CRISPR technology will vigorously promote the progress of HBV integration research in the future. In summary, exploring the characteristics and mechanisms in HBV integration holds significant importance for an in-depth comprehension of viral integration.

New insights into hepatitis B virus lymphotropism: Implications for HBV-related lymphomagenesis

HBV is one of the most widespread hepatitis viruses worldwide, and a correlation between chronic infection and liver cancer has been clearly reported. The carcinogenic capacity of HBV has been reported for other solid tumors, but the largest number of studies focus on its possible lymphomagenic role. To update the correlation between HBV infection and the occurrence of lymphatic or hematologic malignancies, the most recent evidence from epidemiological and in vitro studies has been reported. In the context of hematological malignancies, the strongest epidemiological correlations are with the emergence of lymphomas, in particular non-Hodgkin's lymphoma (NHL) (HR 2.10 [95% CI 1.34-3.31], p=0.001) and, more specifically, all NHL B subtypes (HR 2.14 [95% CI 1.61-2.07], p<0.001). Questionable and unconfirmed associations are reported between HBV and NHL T subtypes (HR 1.11 [95% CI 0.88-1.40], p=0.40) and leukemia. The presence of HBV DNA in peripheral blood mononuclear cells has been reported by numerous studies, and its integration in the exonic regions of some genes is considered a possible source of carcinogenesis. Some in vitro studies have shown the ability of HBV to infect, albeit not productively, both lymphomonocytes and bone marrow stem cells, whose differentiation is halted by the virus. As demonstrated in animal models, HBV infection of blood cells and the persistence of HBV DNA in peripheral lymphomonocytes and bone marrow stem cells suggests that these cellular compartments may act as HBV reservoirs, allowing replication to resume later in the immunocompromised patients (such as liver transplant recipients) or in subjects discontinuing effective antiviral therapy. The pathogenetic mechanisms at the basis of HBV carcinogenic potential are not known, and more in-depth studies are needed, considering that a clear correlation between chronic HBV infection and hematological malignancies could benefit both antiviral drugs and vaccines.

Hepatitis B virus DNA integration as a novel biomarker of hepatitis B virus-mediated pathogenetic properties and a barrier to the current strategies for hepatitis B virus cure

Chronic infection with Hepatitis B Virus (HBV) is a major cause of liver-related morbidity and mortality worldwide. HBV-DNA integration into the human genome is recognized as a frequent event occurring during the early phases of HBV infection and characterizing the entire course of HBV natural history. The development of refined molecular biology technologies sheds new light on the functional implications of HBV-DNA integration into the human genome, including its role in the progression of HBV-related pathogenesis and in triggering the establishment of pro-oncogenic mechanisms, promoting the development of hepatocellular carcinoma. The present review provides an updated and comprehensive overview of the current body of knowledge on HBV-DNA integration, focusing on the molecular mechanisms underlying HBV-DNA integration and its occurrence throughout the different phases characterizing the natural history of HBV infection. Furthermore, here we discuss the main clinical implications of HBV integration as a biomarker of HBV-related pathogenesis, particularly in reference to hepatocarcinogenesis, and how integration may act as a barrier to the achievement of HBV cure with current and novel antiviral therapies. Overall, a more refined insight into the mechanisms and functionality of HBV integration is paramount, since it can potentially inform the design of ad hoc diagnostic tools with the ability to reveal HBV integration events perturbating relevant intracellular pathways and for identifying novel therapeutic strategies targeting alterations directly related to HBV integration.

Hepadnaviral Lymphotropism and Its Relevance to HBV Persistence and Pathogenesis

Since the discovery of hepatitis B virus (HBV) over five decades ago, there have been many independent studies showing presence of HBV genomes in cells of the immune system. However, the nature of HBV lymphotropism and its significance with respect to HBV biology, persistence and the pathogenesis of liver and extrahepatic disorders remains underappreciated. This is in contrast to studies of other viral pathogens in which the capability to infect immune cells is an area of active investigation. Indeed, in some viral infections, lymphotropism may be essential, and even a primary mechanism of viral persistence, and a major contributor to disease pathogenesis. Nevertheless, there are advances in understanding of HBV lymphotropism in recent years due to cumulative evidence showing that: (i) lymphoid cells are a reservoir of replicating HBV, (ii) are a site of HBV-host DNA integration and (iii) virus genomic diversification leading to pathogenic variants, and (iv) they play a role in HBV resistance to antiviral therapy and (v) likely contribute to reactivation of hepatitis B. Further support for HBV lymphotropic nature is provided by studies in a model infection with the closely related woodchuck hepatitis virus (WHV) naturally infecting susceptible marmots. This animal model faithfully reproduces many aspects of HBV biology, including its replication scheme, tissue tropism, and induction of both symptomatic and silent infections, immunological processes accompanying infection, and progressing liver disease culminating in hepatocellular carcinoma. The most robust evidence came from the ability of WHV to establish persistent infection of the immune system that may not engage the liver when small quantities of virus are experimentally administered or naturally transmitted into virus-naïve animals. Although the concept of HBV lymphotropism is not new, it remains controversial and not accepted by conventional HBV researchers. This review summarizes research advances on HBV and hepadnaviral lymphotropism including the role of immune cells infection in viral persistence and the pathogenesis of HBV-induced liver and extrahepatic diseases. Finally, we discuss the role of immune cells in HBV diagnosis and assessment of antiviral therapy efficacy.

Compartmental HBV evolution and replication in liver and extrahepatic sites after nucleos/tide analogue therapy in chronic hepatitis B carriers

BACKGROUND

Hepatitis B virus (HBV) variants are associated with nucleos/tide analogue (NA) response and liver disease but it is unknown whether NA influences extrahepatic HBV persistence.

OBJECTIVES

To investigate HBV replication and genetic evolution in hepatic and extrahepatic sites of chronic hepatitis B (CHB) before and after NA therapy.

STUDY DESIGN

A total of 13 paired plasma, peripheral blood mononuclear cells (PBMC), were collected from chronic HBV carriers at baseline and after a median 53 weeks NA therapy as well as liver biopsy (N=7 baseline, N=5 follow-up). HBV covalently closed circular DNA (cccDNA) and messenger (m) RNA in liver and PBMC were analyzed. HBV polymerase (P)/surface (S), basal core promoter (BCP)/pre-core (PC)/C gene clonal sequencing was done in plasma, peripheral blood mononuclear cells (PBMC), and liver.

RESULTS

Compare to baseline, at ∼53 weeks follow-up, there was no significant change in HBV cccDNA levels in liver (0.2-0.08 copies/hepatocyte, p>0.05) or in PBMC 0.003-0.02 copies/PBMC, p>0.05), and HBV mRNA remained detectable in both sites. At baseline, BCP variants were higher in PBMC vs. liver and plasma. After therapy, drug resistant (DR) and immune escape (IE) variants increased in liver but IE and PC variants were more frequent in PBMC. HBV P/S diversity was significantly higher in PBMC compared to plasma.

CONCLUSION

Continuous HBV replication occurs in liver and PBMC and shows compartmentalized evolution under selective pressure of potent NA therapy.

HBV infection in untreated HIV-infected adults in Maputo, Mozambique

Background

HIV/ HBV coinfected patients are at high risk of developing chronic HBV infection, liver cirrhosis and hepatocellular carcinoma. In Mozambique, where HIV prevalence is one of the highest in the world, HIV-infected patients are scarcely characterized in terms of HBV coinfection and 3TC-resistance mutations profile.

Methods

To characterize ART-naïve HIV-infected adults, with and without HBV coinfection, a cross-sectional study was conducted between May and November 2012 in two health centers from Maputo city, Mozambique. Subjects were consecutively enrolled in the study and, then, tested for hepatitis B surface antigen (HBsAg). Moreover, CD4⁺ T cells count, HBV DNA in plasma, HBV genotyping and 3TC-resistance mutations profile of HBV were assessed in HIV/HBV coinfected patients.

Results

In total, 518 patients were enrolled in the study. The median age was 33 years old and 66.8% were women. The median CD4⁺ T cells count was 361 cells/mm³ and 47 (9.1%) were coinfected with HBV. Out of 46 coinfected patients, 24 (55.2%) had HBV DNA ≥ 20 - < 20 000 and 12 (26.1%) had HBV-DNA ≥20 000. APRI > 2.0 was reported in 4.3% of coinfected and 1.7% of monoinfected patients (p = 0.228), while FIB-4 > 3.25 was reported in 4.4% of coinfected and 1.3% of monoinfected patients (p = 0.112). Genotype A was the most frequent, identified in 25/27 (92.6%) patients, whereas genotype E was present in 2/27 (7.4%) patients. No patient had 3TC-resistance mutations.

Conclusions

This study showed that HBV coinfection was prevalent among ART-naïve HIV-infected adults in Mozambique. Overall, these data highlight the importance of screening HBV coinfection as an integrated measure of HIV routine care to improve health conditions and treatment of HIV/HBV coinfected patients.

Detection of Hepatitis B Virus (HBV) Genomes and HBV Drug Resistant Variants by Deep Sequencing Analysis of HBV Genomes in Immune Cell Subsets of HBV Mono-Infected and/or Human Immunodeficiency Virus Type-1 (HIV-1) and HBV Co-Infected Individuals

The hepatitis B virus (HBV) and the human immunodeficiency virus type 1 (HIV-1) can infect cells of the lymphatic system. It is unknown whether HIV-1 co-infection impacts infection of peripheral blood mononuclear cell (PBMC) subsets by the HBV. Aims To compare the detection of HBV genomes and HBV sequences in unsorted PBMCs and subsets (i.e., CD4+ T, CD8+ T, CD14+ monocytes, CD19+ B, CD56+ NK cells) in HBV mono-infected vs. HBV/HIV-1 co-infected individuals. Methods Total PBMC and subsets isolated from 14 HBV mono-infected (4/14 before and after anti-HBV therapy) and 6 HBV/HIV-1 co-infected individuals (5/6 consistently on dual active anti-HBV/HIV therapy) were tested for HBV genomes, including replication indicative HBV covalently closed circular (ccc)-DNA, by nested PCR/nucleic hybridization and/or quantitative PCR. In CD4+, and/or CD56+ subsets from two HBV monoinfected cases, the HBV polymerase/overlapping surface region was analyzed by next generation sequencing. Results All analyzed whole PBMC from HBV monoinfected and HBV/HIV coinfected individuals were HBV genome positive. Similarly, HBV DNA was detected in all target PBMC subsets regardless of antiviral therapy, but was absent from the CD4+ T cell subset from all HBV/HIV-1 positive cases (P<0.04). In the CD4+ and CD56+ subset of 2 HBV monoinfected cases on tenofovir therapy, mutations at residues associated with drug resistance and/or immune escape (i.e., G145R) were detected in a minor percentage of the population. Summary HBV genomes and drug resistant variants were detectable in PBMC subsets from HBV mono-infected individuals. The HBV replicates in PBMC subsets of HBV/HIV-1 patients except the CD4+ T cell subpopulation.

Compartmentalization of hepatitis B virus: Looking beyond the liver

Hepatitis B virus (HBV) is classically considered to be hepatotropic, but accumulating evidences strongly support its extra-hepatotropic nature too. HBV nucleic acids and proteins have long been reported in a variety of extra-hepatic tissues. Of these, HBV has been studied in details in the peripheral blood mononuclear cells (PBMCs), due to its accessibility. From these studies, it is now well established that PBMCs are permissive to HBV infection, replication, transcription and production of infective virions. Furthermore, molecular evolutionary studies have provided definite evidences towards evolution of HBV genome in PBMCs, which is independent of evolution occurring in the liver, leading to the emergence and selection of compartment specific escape variants or drug resistant strains. These variants/resistant strains of HBV remain restricted within the PBMCs and are rarely detected in the serum/plasma. In addition, HBV infected PBMCs have been reported to be directly transmitted through intrauterine modes, and this infection does not correlate significantly with serum HBV surface antigen or HBV DNA markers. This editorial briefly reviews the current knowledge on this topic, emphasizes and delineates the gaps that are required to be filled to properly understand the biological and clinical relevance of extrahepatic tropism of HBV.

Substance abuse, HIV-1 and hepatitis

During the course of human immunodeficiency virus type 1 (HIV-1) disease, the virus has been shown to effectively escape the immune response with the subsequent establishment of latent viral reservoirs in specific cell populations within the peripheral blood (PB) and associated lymphoid tissues, bone marrow (BM), brain, and potentially other end organs. HIV-1, along with hepatitis B and C viruses (HBV and HCV), are known to share similar routes of transmission, including intravenous drug use, blood transfusions, sexual intercourse, and perinatal exposure. Substance abuse, including the use of opioids and cocaine, is a significant risk factor for exposure to HIV-1 and the development of acquired immune deficiency syndrome, as well as HBV and HCV exposure, infection, and disease. Thus, coinfection with HIV-1 and HBV or HCV is common and may be impacted by chronic substance abuse during the course of disease. HIV- 1 impacts the natural course of HBV and HCV infection by accelerating the progression of HBV/HCV-associated liver disease toward end-stage cirrhosis and quantitative depletion of the CD4+ T-cell compartment. HBV or HCV coinfection with HIV-1 is also associated with increased mortality when compared to either infection alone. This review focuses on the impact of substance abuse and coinfection with HBV and HCV in the PB, BM, and brain on the HIV-1 pathogenic process as it relates to viral pathogenesis, disease progression, and the associated immune response during the course of this complex interplay. The impact of HIV-1 and substance abuse on hepatitis virus-induced disease is also a focal point.

Frequent hepatitis B virus rebound among HIV-hepatitis B virus-coinfected patients following antiretroviral therapy interruption

BACKGROUND

The impact of antiretroviral therapy (ART) interruption in HIV-hepatitis B virus (HBV)-coinfected patients was examined in the Strategic Management of AntiRetroviral Therapy (SMART) study.

METHODS

Plasma HBV DNA was measured in all hepatitis B surface antigen-positive (HBV-positive) participants at baseline, and at months 1, 2, 4, 6, 8, 10, and 12.

RESULTS

Among HBV-positive participants in the ART interruption (drug conservation) (n = 72) and ART continuation (virological suppression) (n = 62) arms, HBV DNA rebound of more than 1 log from baseline at months 1-4 was seen in 31-33% (P = 0.003) and 3-4% (P = 0.017), respectively. Thirteen HBV-positive participants had HBV DNA rebound of more than 3 log, including 12 in the drug conservation arm, of which eight were on tenofovir-containing regimens. Factors independently associated with a HBV DNA rebound were drug conservation arm (P = 0.0002), nondetectable HBV DNA at baseline (P = 0.007), and black race (P = 0.03). Time to ART reinitiation was shorter (7.5, 15.6, and 17.8 months; P < 0.0001) and proportion reinitiating greater (62.5, 46.5, and 39.7%; P = 0.0002) among HBV-positive participants as compared with hepatitis C virus-positive and non-HBV/hepatitis C virus participants in the drug conservation arm. No hepatic decompensation events occurred among HBV-positive participants in either arm.

CONCLUSION

HBV DNA rebound following ART interruption is common and may be associated with accelerated immune deficiency in HIV-HBV-coinfected patients.

Occult hepatitis B in Mexican patients with HIV, an analysis using nested polymerase chain reaction

Hepatitis B virus infection (HBV) with undetectable levels of HBsAg, has been named occult HBV infection and observed in immunosuppressed patients. The aim of this study was to determine the frequency of occult HBV infection in patients with HIV from the West of México, using a combination of serological markers and nPCR. Thirty eight HIV/AIDS patients, 32 men (84.2%) and 6 (5.8%) women, without liver damage related symptoms were studied. HBV coinfection was observed in 10 (26.3%) patients; while only 3 (7.9%) of them were positive to HBsAg. Thus, 7 (18.4%) occult HBV infected patients could be assessed in this population. One (10%) patient with occult HBV infection was positive to anti-HBs, in spite of the reinfection protection attributed to this serological marker. Anti-HBc was detected only in 2 (20%) patients with occult HBV infection. No significant association could be established between occult HBV infection and CD+4 cell count, biochemical, clinical parameters, AIDS stage, or any other risk factor. This study suggest that determination of HBV DNA utilizing highly sensitive techniques, as nPCR, should be performed to detect occult HBV infection, even in the absence of anti-HBc in HIV/ AIDS patients, in order to have a reliable diagnosis, prevent HBV dissemination and acute exacerbation of chronic hepatitis B or even fulminant hepatitis. To our knowledge this is the first study of occult HBV infection in Mexican patients with HIV. However, further studies are necessary in order to determine HBV genotypes and its relationship with evolution and clinical manifestation of the disease.

Hepatitis B and HIV: prevalence, AIDS progression, response to highly active antiretroviral therapy and increased mortality in the EuroSIDA cohort

BACKGROUND

Whether hepatitis B (HBV) coinfection affects outcome in HIV-1-infected patients remains unclear.

OBJECTIVE

To assess the prevalence of HBV (assessed as HBsAg) coinfection and its possible impact on progression to AIDS, all-cause deaths, liver-related deaths and response to highly active antiretroviral therapy (HAART) in the EuroSIDA cohort.

METHODS

Data on 9802 patients in 72 European HIV centres were analysed. Incidence rates of AIDS, global mortality and liver-related mortality, time to 25% CD4 cell count increase and time to viral load < 400 copies/ml after starting HAART were calculated and compared between HBsAg-positive and HBsAg-negative patients.

RESULTS

HBsAg was found in 498 (8.7%) patients. The incidence of new AIDS diagnosis was similar in HBsAg-positive and HBsAg-negative patients (3.3 and 3.4/100 person-years, respectively) even after adjustment for potential confounders: the incidence rate ratio (IRR) was 0.94 [95% confidence interval (CI), 0.74-1.19; P = 0.61]. The incidences of all-cause and liver-related mortalities were significantly higher in HBsAg-positive subjects (3.7 and 0.7/100 person-years, respectively) compared with HBsAg-negative subjects (2.6 and 0.2/100 person-years, respectively). The adjusted IRR values were 1.53 for global (95% CI, 1.23-1.90; P = 0.0001) and 3.58 for liver-related (95% CI, 2.09-6.16; P < 0.0001) mortality. HBsAg status did not influence viral or immunological responses among the 1679 patients starting HAART.

CONCLUSIONS

The prevalence of HBV coinfection was 9% in the EuroSIDA cohort. Chronic HBV infection significantly increased liver-related mortality in HIV-1-infected patients but did not impact on progression to AIDS or on viral and immunological responses to HAART.

Transcriptional Activation of Gammaherpesviral Oncogene Promoters by the Hepatitis B Viral X Protein (HBx)

The latent membrane protein-1 (LMP1) of Epstein-Barr Virus (EBV), saimiri transformation protein (STP) of Herpesvirus saimiri (HVS), and K1 protein of Kaposi's sarcoma-associated herpesvirus (KSHV) are potent gammaherpesvirus oncogenes. To study the possible effects of double viral infection, we investigated the effects of oncogenic early proteins of DNA viruses E1A and E1B (adenovirus-5), E6 and E7 (human papillomavirus-16), HBx (hepatitis B virus), Tag (SV40), and gammaherpesviral oncogene during co-infection in human B-lymphoma (Ramos) and human T-cell leukemia (Jurkat) cell lines. HBx transactivated the promoters of LMP1, STP, and K1 the most, by about six-, three-, and twofold, respectively. Analyses of site-directed mutation and the heterologous promoter system showed that HBx activated the promoter activity of these genes via the NF-kappaB site. These results suggest that HBV (HBx) infection of cells previously infected by gammaherpesviruses transactivates their oncogenes, resulting in possible virus-related disease pathogenesis.

Treatment of chronic hepatitis B in the human immunodeficiency virus-infected patient: present and future

The management of chronic hepatitis B poses specific problems in the presence of human immunodeficiency virus (HIV) coinfection, because therapeutic approaches have to address both hepatitis B virus (HBV) and HIV infections. Response to interferon (IFN-alpha) is lower in HBV-HIV-coinfected than in HIV-negative subjects, especially in patients in advanced stages of immunosuppression. Thus far, there are no data on the performance of the new pegylated forms of IFN-alpha in HBV- and HIV-coinfected persons. After prolonged use of lamivudine, resistance develops in the majority of HBV-HIV-coinfected patients treated with the drug. The more recently approved tenofovir has shown excellent short-term results, and data from longer follow-up studies are eagerly awaited. Several drugs with combined anti-HIV and anti-HBV activity have recently been approved (emtricitabine) or are currently under development. Preliminary results with some of them are quite promising and probably will widen the therapeutic armamentarium against hepatitis B in patients with HIV infection.

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The hepatitis B virus X protein binds to and activates the NH(2)-terminal trans-activation domain of nuclear factor of activated T cells-1

We have previously reported that the hepatitis B virus X protein (HBx) activates nuclear factor of activated T cells (NF-AT), a key regulator of the immune system, by a calcium/calcineurin-dependent pathway, involving dephosphorylation and nuclear translocation of this transcription factor. In addition, we showed that HBx synergizes with potent calcium-mobilizing stimuli to activate NF-AT-dependent transcription, suggesting that additional mechanisms might also be operative in the activation of NF-AT by HBx. Here we demonstrate that HBx activates the NH(2)-terminal transcription activation domain (TAD) of NF-AT1 by a mechanism involving protein-protein interaction. Targeting of HBx to the nucleus did not affect its ability to induce the transcriptional activity of NF-AT1. In contrast, mutations of HBx affecting its functional interaction with general transcription factors abrogated the HBx-induced activity of NF-AT1. Together these results indicate that HBx may exert its function by acting as a nuclear coactivator of NF-AT1.

The hepatitis B virus X protein induces HIV-1 replication and transcription in synergy with T-cell activation signals: functional roles of NF-kappaB/NF-AT and SP1-binding sites in the HIV-1 long terminal repeat promoter

Co-infection with hepatitis B virus (HBV) and human immunodeficiency virus type-1 (HIV-1) is relatively common. However, the impact of this co-infection on the clinical outcome of HIV infection has not been elucidated. We herein demonstrate that the HBV X protein (HBx) superinduces ongoing HIV-1 replication and HIV-1 long terminal repeat (LTR) transcription by synergizing with Tat protein and with T-cell activation signals. Although HBx cooperated with mitogenic stimuli in the induction of reporter plasmids harboring the HIV-1 kappaB enhancer, in both a NF-kappaB-dependent manner and a NF-AT-dependent manner, deletion of this element from the LTR did not affect the HBx-mediated up-regulation in the presence of Tat and/or mitogens. In contrast, mutation of the proximal LTR Sp1-binding sites abolished the HBx-mediated synergistic activation, but only when it was accompanied by deletion of the kappaB enhancer. When HBx was targeted to the nucleus, its ability to synergize with cellular activation stimuli was maintained. Furthermore, mutations of HBx affecting its interaction with the basal transcription machinery abrogated the synergistic activation by HBx, suggesting that this protein exerts its function by acting as a nuclear co-activator. These results indicate that HBx could contribute to a faster progression to AIDS in HBV-HIV co-infected individuals.

Molecular bases for the development of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) is the most common histological form of primary liver cancer; the tumor cells having retained features of hepatocytic differentiation. It is important to emphasize the heterogeneity of the histological background on which the tumor develops. Most HCCs complicate the evolution of an active or inactive cirrhosis. However, some tumors occur on livers with minimal histological changes; the prevalence of such cases varies from one geographical region to the other; being much higher in the southern half of Africa (around 40% of HCCs) than in Asia, America and Europe, where at least 90% of HCCs are associated in the cirrhosis. This heterogeneity is probably a reflection of different environmental and genetic factors. A large number of epidemiological and molecular studies have indeed clearly demonstrated the prime importance of environmental factors to the development of primary liver cancers in humans. Chronic hepatitis B (HBV) and C (HCV) infections are major risk factors. This review will mainly analyse the impact of chronic HBV infection but it is important to emphasize the potential synergistic effects between HBV and HCV, as well as between viral infections and other environmental factors, such as alcohol, chemical carcinogens (see review by Dr Wogan) and other, still poorly defined, hormonal factors which may account for the higher incidence of the tumor in man. Finally the review by Dr Buendia highlights the emerging issue of liver-cancer genetics.

Detection and sequence analysis of hepatitis B virus integration in peripheral blood mononuclear cells

A PCR-based technique was used to detect hepatitis B virus (HBV) integration in peripheral blood mononuclear cells from patients with chronic hepatitis B. Integrated HBV DNA sequences, with virus-cell junctions located in the cohesive region between direct repeat 1 (DR1) and DR2, were found in 2 of 10 studied patients.

Coinfection and superinfection of hepatitis B virus in patients infected with human immunodeficiency virus: no evidence of faster progression to AIDS

The influence of hepatitis B virus (HBV) on the natural history of human immunodeficiency virus (HIV) infection was evaluated in a prospective study of 347 HIV-positive, AIDS-free individuals infected through injecting drug use and sex and with known seroconversion dates. End points were CD4+ cell count < 200 x 10(6) cell/L and AIDS diagnosis. At entry, 229 had seromarkers to HBV; during the study, 107 had a CD4+ cell count < 200 x 10(6) cells/L and 66 developed AIDS. HBsAg chronic carriers, HBV infection-free subjects and those with baseline evidence of prior HBV infection did not differ in rates of progression to end points. Sexual transmission of HIV was significant predictor of CD4+ cell decline to < 200 x 10(6) cells/l [Hazard ratio (HZ): 1.56, 95% confidence interval (CI): 1.06-2.29, p = 0.0232] and progression to AIDS (HZ: 1.91, CI: 1.17-3.11, p = 0.0091). 15 HIV-positive and HBV infection-free patients had HBV seroconversion. They did not differ from those who remained HBV infection-free in rates of progression to end points, but 40% of them became HBsAg chronic carriers. These results suggest that HBV has no influence on progression of HIV disease, but that patients who have HIV before their HBV infection are more likely to become HBsAg chronic carriers than those who are infected with HBV before HIV.

Spontaneous hepatitis B surface antigen clearance in a long-term follow-up study of patients with chronic type B hepatitis. Lack of correlation with hepatitis C and D virus superinfection

We investigated the frequency of HBsAg clearance and the possible role of viral superinfection in a long-term follow-up of 184 patients with chronic hepatitis B (CHB). Our subjects were 184 patients with chronic hepatitis B and the follow-up was 12-216 months (mean 66.2 +/- 53.7 months). The investigative methods used were: immunoenzymatic assays for HBV, HCV, HDV, and HIV markers; polymerase chain reaction (PCR) for HBV DNA; and liver biopsy and immunoperoxidase. During the follow-up, 20 of the 184 patients cleared serum HBsAg. A comparison of patients with persistent HBsAg(group I) and of those who cleared this marker (group II) showed a significant difference in mortality (P = 0.002) between the two groups and a tendency to a more severe exacerbation (flare) in group II (P = 0.07). Antibodies to hepatitis C and D virus as well as antibodies to HIV were equally distributed in both groups. Thirteen patients (7.9%) from group I, but none from group II, subsequently developed hepatocellular carcinoma. These results suggest that the frequency of spontaneous clearance of HBsAg during chronic HBV infection is low. No determinant factor for the clearance was found, including the presence of liver cirrhosis. Serum HBV DNA was undetectable by PCR after clearance in 16 out of 17 patients.

Association between HIV and other DNA viruses in vitro

To investigate the association of human immunodeficiency virus (HIV) with various DNA viruses, including hepatitis B virus (HBV), cytomegalovirus (CMV) and Epstein-Barr virus, (EBV), simultaneous detection of HIV p24 antigen, HBV surface antigen and DNA, CMV-DNA and EBV-DNA expression was performed in phytohemagglutinin-stimulated peripheral blood mononuclear (PBMC) culture supernatants obtained from 54 individuals at risk for HIV infection. HIV expression in PBMC culture supernatants never occurred alone; expression of other viruses was always detected in the 24 samples expressing HIV antigen in vitro. Furthermore, in 16 patients expression of other viruses was detected without HIV expression, and in 14 patients none of the tested viruses were detected. These results indicate a strong association between the presence of HIV antibody and expression of DNA viruses in vitro (p = 0.0001). The coexpression of these viruses could be related to the evolution of HIV infection and AIDS.

Lymphotropism of hepatitis B and C viruses: an update and a newcomer

The mechanisms of viral persistence are complex and include infection of the lymphoid cells. In the case of hepatitis B virus, early observations have suggested that HBV may infect peripheral blood mononuclear cells (PBMC). In animal models studies in chronic hepatitis B patients have further confirmed that viral DNA replicative intermediates, as well as viral transcripts and proteins, can be detected in PBMC under certain conditions. The consequences of this lymphotropism are not fully understood, but it seems likely that PBMC represent an extrahepatic reservoir of virus. The ability of hepatitis C virus to infect PBMC has been demonstrated in vivo and in vitro. The link between HCV lymphotropism and both the natural history of the viral infection and the immunological disorders frequently observed in HCV infections still needs to be established. In both cases, the infection of PBMC by HBV or HCV may represent the source of infection of the liver graft in patients transplanted for end-stage liver disease associated with HBV or HCV.

Distribution of hepatitis B virus DNA sequences in different peripheral blood mononuclear cell subsets in HBs antigen-positive and negative patients

Hepatitis B virus (HBV) DNA sequences have been detected in leucocytes from HBV-infected individuals. The aim of this study was to assess the specificity of HBV for a special leucocyte subset in nine healthy chronic HBV carriers, nine HBs antigen-positive patients with chronic active hepatitis, 16 HBs antigen-negative haemophiliacs with HBc and/or HBs antibodies, and 10 patients with HBV-related systemic necrotizing vasculitis. HBV-DNA sequences were found by Southern blot hybridization in the leucocytes of 15 out of the 44 (34%) patients. The prevalence was not significantly different between the four groups. HBV-DNA was found in the CD4+ cells (9/11) as well as in the CD8+ cells (4/11), B cells (4/12) and monocytes (2/12). In conclusion, leucocytes, and particularly CD4+ lymphocytes, are frequently infected by HBV in patients with HBV serum markers.

Southern hybridisation analysis of HBV DNA in peripheral blood leucocytes and of different cell types: changes during the natural history and with interferon-alpha therapy in patients with hepatitis B virus infection

Hepatitis B virus (HBV) DNA was evaluated in peripheral blood mononuclear cells (PBMC) from 50 individuals utilising Southern hybridisation analysis. HBV DNA sequences were detected in PBMC from 16/29 (55 percent) of chronic hepatitis B virus (HBV) carriers with serum HBeAg and HBV DNA, compared with 1/8 (13%) of carriers with anti-HBe and HBV DNA negative (P = NS). Two of 7 patients with previous HBV infection and chronic liver disease had detectable HBV DNA in PBMC. Of the 19 patients with HBV DNA in PBMC, 18 had high molecular weight species. In addition, five of these had free, monomeric HBV DNA and six patients had low molecular weight bands. For nine of the above patients, total peripheral blood leucocytes were separated into PBMC and polymorphonuclear cells. Four had HBV DNA in PBMC only, two only in polymorphonuclear cells and three in both types of cell. Eleven patients with chronic HBV infection were studied at monthly intervals for 6 months. Six were untreated and five received IFN-alpha. Three patients who responded to IFN-alpha had HBV DNA present in PBMC before therapy, and two became negative. Two of 3 untreated patients had intermittent HBV DNA in PBMC and the other remained persistently negative. Of the patients positive on more than one occasion, the pattern of HBV DNA was similar. Peripheral blood leucocytes often contain multimers of free HBV DNA, more commonly in patients with serum HBeAg and HBV DNA and may occur even in the absence of serum HBsAg. These findings have implications for recurrence of disease after hepatic transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of hepatitis B virus DNA and determination of surface antigen expression in peripheral blood mononuclear cells from patients with AIDS

The polymerase chain reaction (PCR) was used to analyze the presence of hepatitis B virus (HBV) DNA in serum and peripheral blood mononuclear cells (PBMCs) from 20 patients with AIDS with and without conventional HBV serological markers. DNA sequences of HBV were detected in PBMCs from 13 patients, nine of whom were positive for anti-HBc only and four of whom were also positive for anti-HBs. When PBMCs from patients were activated in culture with phytohemagglutinin, the presence of HBsAg could be detected in the culture supernatants from four of 13 patients with HBV DNA in their PBMCs; for two of the four, HBV DNA could also be detected in the culture supernatant after DNA amplification. It was observed that HBV DNA sequences found in PBMCs can be reactivated by mitogen stimulation in some HIV-1 infected patients.

Heroin addicts infected by HBV and HIV have a low prevalence of HBV DNA in peripheral blood mononuclear cells

Several reports show that the prevalence of HBV (hepatitis B virus) carriers in HIV (human immunodeficiency virus) infected populations is significantly higher than in HIV seronegative individuals, independent of the risk group for HIV, that is, homosexuals or drug abusers. In this context, evaluation of the simultaneous presence of HBV and HIV in PBMCs (peripheral blood mononuclear cells) is of particular interest for at least 2 reasons: 1) the possible reciprocal influence of the 2 viruses when they infect the same cell; 2) the possibility that HIV-induced hematological disorders could indirectly influence the settling of HBV in blood cell populations. We report data on the frequency of PCR positivity for HBV DNA in PBMCs from 62 HIV infected patients, rigorously selected by risk group, that is, intravenous use of heroin for at least 3 years and syringe promiscuity. Sixty-seven HIV negative individuals who never used any drug formed the control group. The analysis of the cases positive for HBV DNA in PBMCs showed that: 1) the overall prevalence of PCR positivity found in HIV infected patients was significantly lower than that registered in the control group; 2) PCR positivity among the subjects who were HBsAg negative and anti-HBV positive was extremely low in the HIV infected patients (3.7%) but quite frequent in the HIV negative subjects (37.0%). The results support the hypothesis that, unlike the HIV negative individuals, our HIV infected patients exhibited HBV DNA in PBMCS almost exclusively when they presented with active HBV replication.

Hepatitis B virus replication in diverse cell types during chronic hepatitis B virus infection

Hepatitis B virus-specific nucleic acid sequences and proteins have been detected in extrahepatic tissues of acutely and chronically infected patients. However, apart from peripheral blood mononuclear cells and bone marrow cells, little is known about the specific cell types that permit viral replication. In this study, we assessed the extrahepatic tissues of four patients who died with chronic hepatitis B virus infection and two uninfected controls by means of in situ hybridization and immunohistochemical study. Three of these patients had diffuse extrahepatic distribution of the virus. Hepatitis B virus nucleic acid sequences and proteins were detected in the lymph nodes, spleen, bone marrow, kidney, skin, colon, stomach, testes and periadrenal ganglia. The following cell types were found to be positive for hepatitis B virus: endothelial cells, macrophages/monocytes, hematopoietic precursors, basal keratinocytes, mucosal epithelial cells, stromal fibroblasts and sustentacular and neuronal cells. It is probable that these cells could support viral replication because hepatitis B virus DNA replicative intermediates, viral transcripts and HBsAg and HBcAg proteins were detected in most. These findings may be relevant to the initiation of extrahepatic syndromes associated with chronic hepatitis B virus infection such as vasculitis, glomerulonephropathy, neuropathy and dermatitis.

Aberrant tissue specific expression of the transgene in transgenic mice that carry the hepatitis B virus genome defective in the X gene

The control mechanisms for the transgene expression in mice that carry the hepatitis B virus genome defective in the polymerase and X genes were analyzed. Ten lines of transgenic mouse were established, and in seven lines the surface and e antigens were detected in the serum. In transgenic mice from five lines examined, the transgene was markedly expressed in a broad spectrum of tissues including the kidney, heart, brain, muscle and intestine, but only poorly in the liver. In the kidney and heart the 3.5 kb and 2.1 kb mRNAs were expressed, whereas only the 0.8 kb and 4.0 kb mRNAs were detected in the testis and brain, respectively, suggesting that each of the mRNAs was transcribed through a different control mechanism. The surface, e and core antigens accumulated in the kidney and heart. DNA was hypomethylated at a region closely downstream of the enhancer in the liver, kidney and heart, and a DNase I hypersensitive site was detected upstream of the enhancer in these tissues. In the testis, however, the whole transgene was hypomethylated and the DNase I hypersensitive site was closer to the enhancer. These differences may be relevant to the preferential expression of the 0.8 kb mRNA in the testis, but cannot explain the inefficiency of transgene expression in the liver. Our observations suggest that the X protein is required for efficient expression of the viral gene in the liver but not in other tissues.

The role of hepatitis B virus in the development of primary hepatocellular carcinoma: Part I

Chronic infections with hepatitis B virus (HBV) of humans and animal hepadnavirus infections in their natural hosts are strongly associated with primary hepatocellular carcinoma (HCC). Although viral integrations are found in cells of many HCC, no general viral-specific hepatocarcinogenic mechanism for hepadnaviruses has been identified. In approximately one half of HCC in woodchuck hepatitis virus (WHV) infected woodchucks, viral integrations near the c-myc or N-myc genes have been reported which result in enhanced expression of the respective gene. Such host gene-specific insertional mutagenesis has not been found in HCC of other hepadnavirus infected hosts. Thus in humans, ground squirrels and ducks hepadnaviral integrations appear to be at different host chromosomal DNA sites in each HCC and few integrations have been found within or near any cellular gene. Other possible hepadnavirus-specific carcinogenic mechanisms that are being investigated include transactivation of cellular gene expression by an hepadnavirus gene product (e.g. the X-gene), and mutation of host genes by unknown hepadnavirus-specific mechanisms. It should be noted, however, that chronic hepadnavirus infection is associated with chronic necroinflammatory liver disease with hepatocellular necrosis and regeneration (sometimes leading to cirrhosis in humans), a pathological process that is common to numerous other risk factors for HCC. This suggests the possibility that this pathological process is hepatocarcinogenic irrespective of the inciting agent and the role of hepadnavirus infection is no different from that of other risk factors in causing chronic necroinflammatory liver disease.

Serum and liver hepatitis B virus DNA in chronic hepatitis B after sustained loss of surface antigen

Polymerase chain reaction (PCR) was used to detect hepatitis B virus DNA in the sera and livers of nine patients with chronic hepatitis B after treatment-induced or spontaneous loss of serum hepatitis B surface antigen. Patients were evaluated at intervals ranging from 3 to 67 months after disappearance of hepatitis B surface antigen. PCR was performed using primer pairs from the surface and core gene regions, and surface gene products were quantitated. Liver tissue was also evaluated by in situ hybridization to assess viral transcription. Five of the nine patients had viral DNA detectable in serum by PCR. Quantitation of polymerase chain reaction products in serum and liver showed that the DNA levels tended to decline progressively after antiviral therapy. Six of seven surface antigen-negative patients tested had detectable viral DNA in the liver, and four of the six DNA-positive patients were negative for DNA in serum by PCR. None had surface gene messenger RNA. Thus, it is concluded that hepatitis B virus DNA may be detectable by PCR in liver tissue years after the disappearance of hepatitis B surface antigen, even in the absence of detectable hepatitis B virus DNA in serum.

Hepatitis B virus DNA in peripheral-blood mononuclear cells in chronic hepatitis B after HBsAg clearance

In this study, peripheral-blood mononuclear cells from patients with chronic hepatitis B and spontaneous or therapy-induced disappearance of HBsAg were examined for HBV DNA. Samples were evaluated by in situ hybridization and polymerase chain reaction both before and after clearance of HBsAg. By in situ hybridization, positive signals were observed in 2 of 13 samples collected after HBsAg loss, in 8 of 15 samples before HBsAg loss and in 0 of 4 control patients without serological markers of active or prior HBV infection. When polymerase chain reaction analyses were performed, HBV DNA was detected in 5 of 12 HBsAg-negative samples and 10 of 15 HBsAg-positive samples from the study group. Testing of mononuclear cells after disappearance of HBsAg revealed that two of eight patients were HBV DNA positive by in situ hybridization and by polymerase chain reaction, whereas two additional patients were positive by polymerase chain reaction alone. Mononuclear cell-associated HBV DNA was detected between 2 and 9 mo after the disappearance of circulating HBsAg by in situ hybridization and as long as 4 yr later by polymerase chain reaction. These data indicate that patients who have undergone HBsAg seroconversion may nonetheless harbor HBV DNA in their peripheral-blood mononuclear cells for prolonged periods.

Infection of peripheral mononuclear blood cells by hepatitis C virus

We investigated the infection of peripheral blood mononuclear cells (PBMNC) by hepatitis C virus (HCV) in 5 patients with HCV-related chronic hepatitis. The presence of HCV-RNA-positive and -negative strands was tested with the polymerase chain reaction (PCR) method. In all subjects, HCV-RNA was shown in PBMNC. In 3 cases, HCV-RNA was shown in the T- and B-cell populations, with viral RNA also present in the monocyte-macrophage fraction of two of these. HCV-RNA-negative stranded molecules, indicative of the viral multiplication, were significantly increased in cells maintained in cultures with PHA/PMA stimulation. The results indicate that HCV infect blood mononuclear cells, thus suggesting that this cellular tropism may play a role in HCV infection.

Human immunodeficiency virus type 1 and hepatitis B virus transcription in peripheral blood lymphocytes from co-infected subjects

The molecular characteristics of peripheral blood lymphocyte (PBL) infection by hepatitis B virus (HBV) were studied in human immunodeficiency virus type 1 (HIV-1) infected subjects using highly sensitive polymerase chain reaction (PCR) based techniques. DNA and RNA samples were purified from PBLs of HIV-1 infected individuals, regardless of their HBV serological status and assayed using PCR and reverse-transcription (RT) PCR, respectively. The data shown here are an extension of previous reports documenting HBV and HIV-1 co-infection of PBLs and indicate that transcriptionally active HBV infection of PBLs is detectable in a significant proportion of asymptomatic HIV-1 infected patients.

Viral inhibition of the interferon system

In response to interferon (IFN), cells develop an antiviral state in which the replication of a wide spectrum of RNA and DNA viruses is inhibited. Viruses have evolved a variety of mechanisms to inhibit the production and action of the interferons. Interferon action may be blocked by inhibition of the post-receptor signalling pathway, which prevents the expression of a number of proteins with antiviral properties. Other viruses prevent the action of specific, interferon-induced antiviral systems. In particular, the action of the dsRNA-dependent protein kinase (DAI) is inhibited by a variety of different viruses, indicating the fundamental importance of this enzyme to the antiviral response.

Thyroid function tests in patients with acquired immune deficiency syndrome and healthy HIV1-positive out-patients

The thyroid function tests as well as evidence of thyroiditis were studied in 18 male patients with acquired immune deficiency syndrome (AIDS) and 12 healthy HIV1-positive persons compared with an age-matched control group. Serum total thyroxine was not significantly different between the groups, but both serum total triiodothyronine, triiodothyronine uptake test, and free thyroid hormone indices showed significantly decreasing values from HIV1-positive healthy persons to AIDS patients compared with controls (P value from less than 0.05 to less 0.001). Serum TBG was elevated in HIV1-positive subjects and in patients with AIDS, with a significant inverse correlation with the T3-uptake test (Spearman's rho = 0.657, P less than 0.01). There was no correlation between thyroxine binding globulin and the other measured variables. The serum level of thyrotropine was not significantly different in the groups, whereas serum thyroglobulin was significantly lowered in the AIDS group. There was no correlation between thyroid function variables and survival time, hepatic function and ratio of T-helper to T-suppressor cells. No evidence of thyroiditis was observed. In conclusion thyroid tests showed an atypical outcome in HIV1-positive patients with or without AIDS compared with the pattern normally seen in non-thyroid illness, and should, therefore, caution the interpretation of the biochemical changes when diagnosing abnormal thyroid function in these patients.

Association of hepatitis B surface antigen and core antibody with acquisition and manifestations of human immunodeficiency virus type 1 (HIV-1) infection

We examined the associations between seropositivity for hepatitis B virus (HBV) with the presence or development of antibodies to human immunodeficiency virus (HIV-1) and with HIV-1 induced T-helper lymphocyte deficiency or acquired immunodeficiency syndrome (AIDS). Serologic data on HBV and HIV-1, cytometric enumeration of CD4+ lymphocytes, clinical events (AIDS by Centers for Disease Control criteria) and hepatitis B vaccination histories were available on 4,498 homosexual participants in the Multicenter AIDS Cohort Study, Men were classified as to previous infection with HBV and prevalent or incident infection with HIV-1. Although there was an association between seropositivity for HBV infection and HIV-1 infection at enrollment (odds ratios anti-HBc 2.6; HBsAg 4.2), the relation between HBV seropositivity and subsequent seroconversion to HIV-1 was weaker (odds ratios 1.3 and 1.6). HIV-1 seroconversion was also associated with a history of certain other sexually transmitted diseases, but predisposing sexual practices did not account for the association between HBV and HIV-1 infection. Seropositivity for HBV infection at entry was not related to initially low or more rapid subsequent decline in T-helper lymphocyte counts and was not associated with an increased incidence of AIDS during 2.5 years of follow-up. History of vaccination against HBV did not appear to decrease susceptibility to HIV-1 infection or to subsequent progression of immunodeficiency. We conclude that prior HBV infection is unlikely to be specifically associated with acquisition of HIV-1 infection and is unrelated to more rapid progression of HIV-1-induced immunodeficiency.

Different forms of hepatitis B virus DNA and expression of HBV antigens in peripheral blood mononuclear cells in chronic hepatitis B

The presence of both hepatitis B virus (HBV) DNA and HBV antigens (HBsAg, HBeAg) was assessed in peripheral blood mononuclear cells (PBMC) from 32 patients chronically infected with HBV. Three different molecular forms of HBV DNA were observed: free monomers (5), high-molecular-weight free concatemers (11), and integrated HBV DNA (9). The HBV DNA patterns in the PBMC were different from those found in liver and did not correlate with any specific profile of serum HBV markers. When the same PBMC were assayed for HBsAg, 22 of the 25 HBV DNA positive samples, but only three of the seven HBV DNA negative samples, were positive. By contrast, none of the PBMC samples from five healthy HBV vaccine recipients gave any positive signal in the HBV DNA or HBsAg assays. In some patients, T and B cells, monocytes, and polymorphonuclear (PMN) cells were assayed separately, showing that the DNA pattern was similar for these different leucocytes subsets and ruling out the possibility that these patterns might reflect PMN cell contamination. Thus, in chronic HBV infection, 87.5% (28/32) of patients were found to contain at least one HBV marker in their PBMC, and a strong correlation was found between the presence of HBV DNA and viral antigens, suggesting a specific expression of HBV encoded proteins.

Hepatitis B virus transcripts and surface antigen in human peripheral blood lymphocytes

The presence of hepatitis B virus (HBV) genome, transcripts, and antigens (HBsAg, HBcAg, HBeAg) was examined in peripheral blood lymphocytes (PBL) from 12 patients with HBsAg-positive (B) chronic active hepatitis (CAH) and 8 normal donors by Southern and Northern blot techniques and enzyme-linked immunoassays (ELISA). HBV DNA was detected in 5 patients with B-CAH as extrachromosomal, full-length monomers of 3.2 kb. In 3 of these patients Northern blot analysis revealed the presence of the 3.6-3.8 kb RNA species, which were accompanied in one case by the HBsAg-specific 2.4 kb transcript. An ELISA performed on cell lysate obtained from this patient showed low but detectable amounts of HBsAg as compared to control PBL incubated with up to 50 micrograms/ml of the viral antigen. Serum HBV DNA was found in 3 patients with B-CAH, whereas all individuals positive for cellular HBV DNA had circulating HBeAg. These data indicate that lymphocytes from some patients with hepatitis B can harbor a transcriptionally and translationally active HBV genome.

Hepatitis B virus infection of peripheral blood mononuclear cells is common in acute and chronic hepatitis

Hepatitis B virus (HBV) infection of peripheral blood mononuclear cells (PBMCs) has been observed in all stages of liver disease. Thus far all information about the physical state of HBV in mononuclear blood cells comes from Southern blot analysis and in situ hybridization. In this study we focused our attention on the presence of HBV DNA sequences in PBMCs of 30 patients with acute type B hepatitis and 6 patients with chronic active hepatitis by utilizing both Southern blot analysis and the polymerase chain reaction (PCR). Southern blot analysis showed no HBV DNA sequences in PBMCs of the acute hepatitis patients, although the sensitivity of our method enabled us to detect as little as 1 pg of cloned HBV insert. As far as the chronic hepatitis patients are concerned Southern blot analysis revealed the presence of HBV DNA sequences in 5 out of 6 patients but intermittently at successive follow-up times. On the other hand we were able to demonstrate the presence of HBV related sequences in 14 out of 30 acute hepatitis patients (5 HBeAg positive, 9 antiHBe positive) and in all 6 chronic hepatitis patients by PCR. Our results indicate that the involvement of PBMCs with HBV during acute HBV infection occurs at a very low level, often below the detection limit of the Southern blot technique.

CD4-independent, productive human immunodeficiency virus type 1 infection of hepatoma cell lines in vitro

Five hepatoma cell lines, including CZHC/8571, PLC/PRF/5, Hep3B, HepG2, and HUH7, were inoculated with three diverse isolates of human immunodeficiency virus type 1 (HIV-1). Productive infection was noted in all hepatoma cell lines, and expression of viral p24 antigen lasted for over 3 months, but its level decreased in proportion to the number of viable cells. HIV-1 antigens were also found in the cells by immunohistochemical staining and radioimmunoprecipitation assay, as were viral RNA by in situ hybridization and HIV-1-like particles by electron microscopy. Virus yield assays were also positive on supernatant fluids collected from hepatoma cultures inoculated with HIV-1. Despite their susceptibility to infection, all five hepatoma cell lines were negative for CD4 by immunofluorescence and for CD4 mRNA by slot-blot hybridization. In addition, HIV-1 infection of hepatoma cell lines was not blocked by anti-CD4 monoclonal antibody or soluble CD4. Together, these findings clearly demonstrate that all five hepatoma cell lines were susceptible to productive infection by HIV-1 in vitro via a CD4-independent mechanism.

Hepatitis B virus X protein transactivates the long terminal repeats of human immunodeficiency virus types 1 and 2

The X gene product of the hepatitis B virus (HBV) has been expressed transiently in HepG2 cells, and the 17-kilodalton protein has been detected by Western (immuno-) blot analysis. Cotransfection of the X gene with the long terminal repeat of human immunodeficiency virus type 1 or 2 results in a stimulation of long terminal repeat-directed expression that is higher than the X-induced stimulation of the HBV enhancer linked to either autologous promoter or to the heterologous simian virus 40 promoter. A frameshift mutation abolished this transactivation. In vitro nuclear transcription assays revealed that HBV X acts at the transcriptional level. The carboxy terminus of the HBV X protein does not seem to be necessary for its transactivating activity, as demonstrated by using HBV X protein deletion mutants.