Hepatitis B virus DNA replication in peripheral blood mononuclear cells

Ligase chain reaction (LCR) assay for semi-quantitative detection of HBV DNA in mononuclear leukocytes of patients with chronic hepatitis B

A ligase chain reaction (LCR)-based approach to detect hepatitis B virus (HBV) DNA in peripheral blood mononuclear cells (PBMC) is described. Using this new amplification technique, we determined semi-quantitatively the amount of a short HBV S-gene fragment in PBMC lysates of 25 patients with different forms of chronic hepatitis (group A (n = 8), hepatitis B s antigen (HBsAg)+/hepatitis B e antigen (HBeAg)+; group B (n = 9), HBsAg+/HBeAg-; group C (n = 8), HBsAg-/HBeAg-). The LCR results were compared with the findings obtained with polymerase chain reaction (PCR) amplification of three distinct HBV gene regions (preS1/2, S and C) and related to the serological profiles of the patients. Depending on the primer pair used for PCR amplification, sensitivity of HBV LCR in PBMC was equivalent or slightly superior to PCR. The highest positivity rate for HBV DNA was observed in the HBeAg+ and HBV DNA seropositive group (8/8) and was lower in the other patient groups B (4/9) and C (1/8). Interestingly, HBV gene sequences could also be detected in the lymphocytes of an HBsAg negative patient and in two patients from group B who were both negative for serum viral particles by PCR. The rapid LCR procedure represents a reliable alternative to PCR for the sensitive detection of HBV DNA in PBMC samples. In combination with the automated IMx(TM)-system the new amplification technique may be routinely used for screening for HBV in whole blood samples and thus may help to better evaluate the risk of HBV reinfection in liver transplant recipients.

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.

Detection of hepatitis C virus RNA in peripheral blood mononuclear cells and in saliva

The nested polymerase chain reaction (PCR) technique was applied to investigate hepatitis C virus (HCV) RNA in the peripheral blood mononuclear cells (PBMCs), saliva, and serum of patients with chronic type C hepatitis. The specificity of the amplified products was analyzed and confirmed by agarose gel electrophoresis, Southern blot hybridization, and restriction endonuclease pattern analysis. HCV RNA was detectable in the PBMCs of 24% (12/50) of the patients. The HCV RNA detected in PBMCs was not due to the contamination from plasma, since no viral sequences could be detected in the third washing of PBMCs. Of the 12 patients with HCV RNA in PBMCs, five were negative for HCV RNA sequences in the serum. Thus the presence of HCV RNA in PBMCs was not strictly correlated to the results for sera. Among 25 patients with HCV RNA in their saliva, 18 were negative for PBMCs. Among 25 patients without HCV RNA in their saliva, five had HCV RNA in PBMCs. In conclusion, PBMCs are an extrahepatic target for chronic HCV infection. However, we do not suggest that PBMCs act as a vehicle for carrying HCV to saliva, since the presence of HCV RNA in PBMCs and in saliva was not closely correlated.

2',5'-Oligoadenylate synthetase activity in peripheral blood lymphocytes as a clinical marker in interferon therapy for chronic hepatitis B

Treatment of chronic hepatitis B (CHB) with human leukocyte interferon (IFN-alpha) was studied in terms of increase of 2',5'-oligoadenylate (2-5A) synthetase activity in peripheral blood lymphocytes (PBL) after IFN-alpha administration. The 2-5A synthetase activity in PBL increased to a maximum 16-24 h after IFN-alpha injection and then gradually decreased, while serum HB virus DNA polymerase (HBV-DNAP) activity, which corresponds to the amount of HBV virions in the serum, decreased to a minimum after about 48 h. Increase in 2-5A synthetase activity was followed about 1 day later by decrease in DNAP activity. Furthermore, of 9 patients treated with IFN for at least 22 weeks and observed for over 1 year after IFN treatment, the effective 5 cases in which HBeAg disappeared during IFN therapy and did not reappear showed rather high increases in 2-5A synthetase activity, whereas the ineffective 4 cases in which HBeAg remained positive at the end of IFN therapy showed little increases in enzyme activity. The present study suggests that prescreening by 2-5A synthetase assay before IFN therapy should be useful for obtaining better results in IFN treatment of CHB patients.

Fulminant hepatitis B in successive female sexual partners of two anti-HBe-positive males

In two separate families, consecutive, unrelated female sexual partners of a symptom-free, male, HBsAg-positive carrier died of fulminant hepatitis B. Although one man was HBeAg positive on the first occasion, both men were considered of low infectivity, being anti-HBe positive, negative for serum DNA polymerase activity, and negative for serum hepatitis B virus (HBV) DNA when their second partners presented with fulminant hepatitis B. By means of molecular hybridisation techniques, both men were found to have HBV DNA (3.2 kb) in seminal fluid, sputum, saliva, peripheral blood leucocytes, and liver.

Hepatitis B virus DNA in mononuclear blood cells. A frequent event in hepatitis B surface antigen-positive and -negative patients with acute and chronic liver disease

We have investigated 38 hepatitis B surface antigen (HBsAg)-positive and 34-negative patients with acute and chronic liver disease for the presence of hepatitis B virus (HBV) DNA in peripheral mononuclear blood cells. Among the HBsAg-positive subjects HBV DNA was detected in the mononuclear cells of asymptomatic HBV carriers (2/6), patients with acute hepatitis (8/8), chronic active hepatitis (18/21), and with hepatocellular carcinoma (2/3); the viral DNA sequences were also identified in the mononuclear cells of patients with HBsAg-negative acute hepatitis (2/3), chronic active hepatitis (5/15) and hepatocellular carcinoma (5/16), some of these showing no evidence of HBV by conventional serological markers. By contrast HBV DNA was not detected after resolution of the acute viral infection. For 7 patients different mononuclear cell-enriched subpopulations were assayed and the viral DNA was observed in T lymphocytes (both OKT4+ and OKT8+ enriched subsets) and/or in B enriched lymphocytes; the restriction DNA patterns showed in some patients a genetic organisation of the viral DNA similar to those observed in the liver (including free monomeric and oligomeric HBV DNA and results consistent with integrated viral sequences); however, no HBV DNA replicative forms were detected. These results show that the hepatitis B virus infection of mononuclear blood cells (including lymphoid cells) is a frequent event at all stages of the viral infection which might be related to immunological abnormalities observed in HBV carriers; in addition the mononuclear blood cells analysis may provide an insight to the liver cells status.