Intracellular interferon signalling pathways as potential regulators of covalently closed circular DNA in the treatment of chronic hepatitis B

Heterogeneity of immune control in chronic hepatitis B virus infection: Clinical implications on immunity with interferon-α treatment and retreatment

Hepatitis B virus (HBV) infection is a global public health issue. Interferon-α (IFN-α) treatment has been used to treat hepatitis B for over 20 years, but fewer than 5% of Asians receiving IFN-α treatment achieve functional cure. Thus, IFN-α retreatment has been introduced to enhance antiviral function. In recent years, immune-related studies have found that the complex interactions between immune cells and cytokines could modulate immune response networks, in-cluding both innate and adaptive immunity, triggering immune responses that control HBV replication. However, heterogeneity of the immune system to control HBV infection, particularly HBV-specific CD8⁺ T cell heterogeneity, has consequ-ential effects on T cell-based immunotherapy for treating HBV infection. Altogether, the host’s genetic variants, negative-feedback regulators and HBV components affecting the immune system's ability to control HBV. In this study, we reviewed the literature on potential immune mechanisms affecting the immune control of HBV and the clinical effects of IFN-α treatment and retreatment.

Role of epigenetic modification in interferon treatment of hepatitis B virus infection

Human hepatitis B virus (HBV) is a small, enveloped DNA virus that causes acute and chronic hepatitis. Chronic hepatitis B (CHB) is associated with hepatocellular carcinoma pathogenesis. Interferons (IFNs) have been used for the treatment of CHB for a long time, with advantages including less treatment duration and sustained virological response. Presently, various evidence suggests that epigenetic modification of the viral covalently closed circular DNA (cccDNA) and the host genome is crucial for the regulation of viral activity. This modification includes histone acetylation, DNA methylation, N6-methyladenosine, and non-coding RNA modification. IFN treatment for CHB can stimulate multiple IFN-stimulated genes for inhibiting virus replication. IFNs can also affect the HBV life cycle through epigenetic modulation. In this review, we summarized the different mechanisms through which IFN-α inhibits HBV replication, including epigenetic regulation. Moreover, the mechanisms underlying IFN activity are discussed, which indicated its potential as a novel treatment for CHB. It is proposed that epigenetic changes such as histone acetylation, DNA methylation, m6A methylation could be the targets of IFN, which may offer a novel approach to HBV treatment.

The efficacy of pegylated interferon alpha-2a and entecavir in HBeAg-positive children and adolescents with chronic hepatitis B

Background and objectives

Pegylated interferon alpha-2a (peg-IFN α-2a) and entecavir (ETV) are both recommended as the first-line antiviral drugs for chronic hepatitis B (CHB) at present. We aimed to compare the efficacy and safety between peg-IFN α-2a and ETV initial therapy in children and adolescents with CHB and investigate the potential factors affecting the treatment response during the first 48 weeks.

Methods

We retrospectively selected 70 treatment-naïve children and adolescents with CHB who received peg-IFN α-2a(n = 26) or ETV(n = 44) as initial therapy and completed 48-week follow-up for data analysis. Blood samples before treatment were collected from 26 patients of the cohort to assess the cytokine profiles.

Results

We found that initial peg-IFN therapy results in higher rates of hepatitis B surface antigen (HBsAg) serological response (SR) but lower rates of virological and biochemical response rates compared to ETV at week 48. As for achieving hepatitis B e antigen (HBeAg) SR, peg-IFN was comparable to ETV in the univariate analysis and turned out to be better than ETV after adjustment for important baseline factors. We also found that elevated pre-treatment IL-18 level was significantly associated with HBeAg SR, and remained as the only independent factor of predicting HBeAg SR after adjustment for other important factors. No serious adverse effects of the 2 drugs were reported during the 48-week follow-up.

Conclusions

comparing to ETV, peg-IFN was superior in achieving HBsAg and HBeAg SR; higher baseline IL-18 levels were independently associated with HBeAg SR in this study of children and adolescents with CHB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03482-0.