Influence of hepatitis delta virus replication in the presence of hepatitis B virus DNA in peripheral blood mononuclear cells

Hepatitis B virus nucleic acids associated with human peripheral blood mononuclear cells do not originate from replicating virus

There have been numerous reports suggesting that human peripheral blood mononuclear cells (PBMCs) can be productively infected with human hepatitis B virus (HBV). We therefore examined whether the PBMCs can be used to establish an in vitro infection system for HBV. Freshly purified PBMCs were incubated with HBV with or without mitogen stimulation. Successful infection was tested using a newly developed PCR method that can differentiate between the relaxed circular (RC) DNA of the virus inoculum and the covalently closed circular (CCC) DNA which is formed only after successful virus entry. This method enables virus uptake to be proven even if the infection is abortive because there is no gene expression because of the lack of liver specific gene expression factors. All attempts to detect CCC DNA after incubation of PBMCs with HBV failed. On the contrary, CCC DNA could easily be detected in infected liver or after in vitro infection of primary human hepatocytes. Because this result appeared to be contradictory to the published data, we analyzed PMBCs isolated from infected patients. We could confirm that HBV DNA and RNA are associated with these cells. However, even after restimulation with mitogens, we could only detect RC DNA. Moreover, we could also demonstrate that viral RNA is present in free virus. Apparently, a certain amount of defective particles do not reverse transcribe the packaged pregenomic RNA. In summary we found no evidence that PMBCs can be infected with HBV and conclude that all previous observations can be explained by adsorbed virus.

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.

Analysis of hepatitis B precore region in serum and liver of chronic hepatitis B virus carriers

Using an oligonucleotide hybridization assay we studied the prevalence of wild-type and the predominant pre-core mutant hepatitis B virus in serum and liver of 49 antibody to hepatitis B e antigen carriers and three hepatitis B e antigen positive patients. Of the 45 serum samples from the anti-HBe carriers analyzed (no serum sample was available in four patients), 36 (80%) had hepatitis B virus DNA. In 26 of these 36 patients (72%) a mixed population was detected, wild-type genome alone was found in six patients (16%), the single mutant (nucleotide position 1896), in three cases (8%) and in one patient (2%) the viral DNA had the two nucleotide mutation (1896 and 1899). Of the liver biopsies from the 36 anti-HBe patients studied (no liver biopsy was available in 13 patients), 33 (92%) had hepatitis B virus DNA. A mixed viral population was detected in 23 patients (69%), only wild-type virus or a single mutation was found in eight (34%) and two patients (8%), respectively. In all cases, wild-type was the predominant genome. In serum and liver samples from the same patient, we found a concordance of the presence of wild-type HBV and the pre-core mutants studied in 23/26 (88%) of the patients. Alanine aminotransferase levels were higher (p < 0.01) and the duration of hepatitis B surface antigen carrier lower (p < 0.02) in patients with a predominance of precore mutant in comparison to wild-type.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous exacerbation of disease activity in patients with chronic delta hepatitis infection: the role of hepatitis B, C or D?

Forty-six patients with chronic hepatitis delta virus infection were followed between 6 and 116 mo (mean = 32.8 mo; median = 24 mo). Nineteen patients (41%) demonstrated clinical courses with episodes of biochemical reactivation (ALT levels greater than or equal to 10 times baseline values [group A]). Twenty-seven patients (59%) had stable clinical courses without biochemical reactivation (group B). Patients in group A were younger than those in group B (30.5 vs. 35.3 yr; p = 0.03), were less likely to be intravenous drug abusers (16% vs. 52%; p = 0.01) and were more likely to be homosexual (58% vs. 22%; p = 0.01). Serum hepatitis B virus DNA, hepatitis delta virus RNA, IgM antibody to HBc, HBeAg, antibody to HBe and IgG and IgM antibody to hepatitis delta virus were measured in all patients. In group A, these markers were studied before and during reactivation and during remission. In group B, these parameters were studied in a random fashion at 7- to 10-mo intervals. The presence of antibodies to human immunodeficiency virus and hepatitis C virus was assessed in all patients. A total of 38 biochemical reactivation episodes was noted among the 19 patients in group A. Eleven had sequential changes in hepatitis delta virus markers, suggesting that the exacerbations were due to hepatitis delta virus. In three, the sequential changes of viral markers were consistent with the exacerbations due to hepatitis B virus. In five other patients, no sequential changes in viral markers could be demonstrated to correlate with the biochemical exacerbations.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B virus. New and evolving issues

Recent developments in molecular biology have advanced our understanding of the pathogenesis of HBV-induced disease. New data derived from the molecular analysis of clinical material have begun to bridge the gap between bench research and the clinical arena. In this review, we consider topics that have relevance to clinical management and that have not been summarized in the recent literature. The recent advances that have been made in the areas of HBV variants, in vitro cell culture systems, and extrahepatic infection are discussed in greater detail.

Production of 22 nm HBsAG particles by human lymphocytes infected with a recombinant vaccinia virus containing the coding sequence for hepatitis B virus surface antigen

To examine the possible role of lymphocytes in the course of hepatitis B virus infection, we studied peripheral blood lymphocytes and Epstein-Barr virus transformed B-cells for their capability to produce hepatitis B virus gene products. Infection of these cells with a recombinant vaccinia virus containing the hepatitis B virus surface antigen resulted in the production and secretion of hepatitis B virus surface antigen shortly after infection reaching a peak after three days. When the supernatants of the cells were analyzed on density gradients, a peak of reactivity for hepatitis B virus surface antigen was reached at 1.21 g/cm3. Electron microscopy revealed the presence of spherical and filamentous HBsAg particles. These findings show that human lymphocytes are capable of producing hepatitis B virus surface antigen.