Effects of alpha-interferon on gamma-interferon production of peripheral blood mononuclear cells in hepatitis B virus carriers

Sonographic fatty liver and hepatitis B virus carrier status: Synergistic effect on liver damage in Taiwanese adults

AIM: To examine the epidemiology of hepatitis B virus carrier status (HBVC) and sonographic fatty liver (SFL) in Taiwanese adults, and to evaluate their possible interaction in inducing liver damage (LD). From an epidemiological viewpoint, we analyzed previous studies which indicated that fatty liver sensitizes host immune response to HBV infection and enhances liver damage.

METHODS: A cross-sectional retrospective analysis of health records including medical history, physical examination, abdominal sonogram, blood biochemistry and hepatic virological tests. We utilized the Student’s t-test, chi-square, multivariate logistic regression and synergy index to assess risks for LD.

RESULTS: Among a total of 5406 Taiwanese adults (mean age 46.2 years, 51.5% males), the prevalence of LD, HBVC and SFL were 12.3%, 15.1% and 33.4%, respectively; 5.1% of participants had SFL plus HBVC. Multivariate logistic regression analysis demonstrated that male gender (odds ratio (OR) = 2.8, 95% confidence interval (CI): 2.3-3.5), overweight state (OR = 1.6, 95% CI: 1.3-2.0), HBVC (OR = 2.5, 95% CI: 2.0-3.1) and SFL (OR = 4.2, 95% CI: 2.2-5.3) were independently associated with LD. Synergism analysis showed that the adjusted OR for LD in adults with HBVC-alone was 3.3 (95% CI: 2.4-4.6), SFL-alone, 4.7 (95% CI: 3.7-6.1) and combined HBVC and SFL, 9.5 (95% CI: 6.8-13.3); the synergy index was 1.4 (95% CI: 1.001-2.0).

CONCLUSION: In Taiwanese adults, SFL plus HBVC have a significant synergistic association with LD.

The effects of prednisolone and interferons on serum macrophage colony stimulating factor concentrations in chronic hepatitis B

BACKGROUNDS/AIMS

Serum concentrations of macrophage-colony stimulating factor (M-CSF) are increased in parallel with hepatic inflammation. The aim of this study was to assess the immunologic significance of elevated M-CSF in patients with chronic hepatitis B virus infection.

METHODS

The subjects included 20 asymptomatic HBV carriers and 45 patients with chronic hepatitis B, including 8 undergoing prednisolone treatment, 10 experiencing an acute exacerbation, and 12 undergoing daily administration of interferons.

RESULTS

Serum concentrations of M-CSF significantly decreased during prednisolone administration, but significantly increased following prednisolone withdrawal, similar to the increase during acute exacerbation. Changes in the lipopolysaccharide-stimulated production of interleukin-1-beta and tumor necrosis factor-alpha by peripheral whole blood, or of interferon-gamma by peripheral blood mononuclear cells showed a similar pattern. Serum concentrations of M-CSF did not correlate with the titers of HBV-DNA or HBV-DNA polymerase activity. However, serum M-CSF peaked preceding seroconversion to HBe antibody in three HBe antigen positive patients. Exogenous interferon-alpha, -beta, or -gamma induced significant elevation in serum M-CSF concentrations, irrespective of changes in the serum alanine aminotransferase levels.

CONCLUSIONS

Increased serum M-CSF is closely associated with increased serum interferons and/ or proinflammatory cytokines produced by peripheral blood cells during hepatic inflammation in chronic hepatitis B. This may be a consequence of the altered cytokine cascade resulting from the host immune response against hepatitis B virus.

Tumor necrosis factor-alpha and interferon-gamma inhibit synergistically viral replication in hepatitis B virus-replicating cells

The effects of tumor necrosis factor-alpha and/or interferon-gamma on the replication of hepatitis B virus were examined using HB611 cells. These cells were derived from human hepatoblastoma cells, Huh6, by integrating hepatitis B virus DNA, and produce hepatitis B virus continuously. Each of the cytokines inhibited hepatitis B virus replication in the cells assessed as the amount of episomal hepatitis B virus DNA, without a decrease in cell viability. When the two cytokines were administered together, the inhibitory effect became greater. Incubation of the cells with 1,000 U/ml tumor necrosis factor-alpha decreased HBV DNA replicative intermediates by 55%, and that with 1,000 U/ml interferon-gamma decreased these by 51%. Furthermore, incubation with 1,000 U/ml tumor necrosis factor-alpha and 1,000 U/ml interferon-gamma in combination decreased HBV DNA replicative intermediates by 71%. In contrast, the amount of hepatitis B virus RNA and secretion of hepatitis B e antigen were not apparently reduced by the cytokines, and 2',5'-oligoadenylate synthetase activity was not detected in the supernatant. These results suggest that tumor necrosis factor-alpha and interferon-gamma inhibit hepatitis B virus replication by blocking some step in reverse transcription and that the 2',5'-oligoadenylate synthetase is not involved in the mechanism underlying the inhibition by these two cytokines.

Interferon-alpha-2a. A review of its pharmacological properties and therapeutic use in the management of viral hepatitis

Interferon-alpha-2a is a recombinant interferon with antiviral, antitumour and immunomodulatory properties. Clinical studies have demonstrated that the drug offers therapeutic benefit in patients with some forms of chronic viral hepatitis. Remission, as measured by clearance of viral DNA and hepatitis B 'e' antigen (HBeAg), and normalisation of serum alanine aminotransferase levels, is observed in approximately 30 to 45% of patients with chronic hepatitis B receiving interferon-alpha-2a (2.5 to 18MU administered 3 times/week); about 5 to 15% of untreated controls remit spontaneously every year. Complete recovery [with loss of hepatitis B surface antigen (HBsAg)] is usually noted in < 20% of treated individuals. Similar response rates have been reported in the relatively small number of children evaluated to date. Although numerous studies have shown that interferon-alpha-2a (at various dosages) induces biochemical amelioration of chronic hepatitis C in approximately 50 to 75% of patients, relapse is common. Thus, long term remission may only be observed in about 15 to 30% of treated patients. On the other hand, this disorder remits spontaneously in only a few patients. The role of interferon-alpha-2a in the treatment of chronic hepatitis D remains unclear. Although preliminary data suggest it may be beneficial, cessation of therapy is generally followed by relapse. As with other types of interferons, most patients receiving interferon-alpha-2a experience an 'influenza-like' syndrome, which tends to diminish with continuing therapy. Other effects such as fatigue, lethargy, anorexia and weight loss are usually dose-limiting. Serum neutralising antibodies develop in approximately 10 to 20% of treated patients. Thus, although response rates are less than optimal, interferon-alpha-2a is a drug of first choice amongst the limited therapeutic options available for the management of well-compensated chronic viral hepatitis B or C.

Effects of hepatitis B virus antigens on interferon-gamma production of peripheral blood mononuclear cells from hepatitis B virus carriers and healthy individuals

BACKGROUND

Although the precise mechanisms of persistent infection by hepatitis B virus are not yet known, several lines of studies suggest that hepatitis B e antigen in sera might modulate the immune response of the host. The aim of this study was to clarify the effects of hepatitis B virus antigen on cytokine production of lymphocytes.

METHODS

We studied the effects of recombinant hepatitis B core antigen and surface antigen on interferon-gamma production of phytohemagglutinin-stimulated peripheral blood mononuclear cells from hepatitis B virus carriers and healthy individuals. Hepatitis B core antigen used in this study shared the antigenic site responsible for hepatitis B core and e antigen.

RESULTS

Although pre-incubation of peripheral blood mononuclear cells with hepatitis B core/e antigen followed by stimulation with phytohemagglutinin significantly reduced the production of interferon-gamma, pre-incubation with hepatitis B surface antigen did not affect them.

CONCLUSIONS

These results indicate that hepatitis B core/e antigen has the ability to inhibit interferon-gamma production of lectin-stimulated peripheral blood mononuclear cells in vitro, suggesting that secretion of hepatitis B e antigen into sera might be how hepatitis B virus escapes the immuno-surveillance system of the host.

Alpha-interferon enhances gamma-interferon production of peripheral blood mononuclear cells pre-activated with phytohemagglutinin

The question of whether the state of T cell activation is responsible for gamma-interferon production in response to alpha-interferon was determined. When peripheral blood mononuclear cells were pre-incubated with phytohemagglutinin for 3 days, their gamma-interferon production was found to be augmented by alpha-interferon, accompanied by an increased proportion of DR-positive T cells. This did not occur with fresh cells. The effect was dose-dependent and inhibited by anti-alpha-interferon antibody. Therefore, alpha-interferon was considered to enhance the production of gamma-interferon of pre-activated peripheral blood mononuclear cells but not of resting ones. In conclusion, alpha-interferon augmented the production of gamma-interferon of peripheral blood mononuclear cells only when they had already been activated, suggesting a role of alpha-interferon as a modulator of the cellular immune response.