Effect of conventional interferon-α in patients with HBeAg-positive chronic hepatitis B: a systematic review and meta-analysis

Interferon and interferon-stimulated genes in HBV treatment

Human hepatitis B virus (HBV) is a small enveloped DNA virus with a complex life cycle. It is the causative agent of acute and chronic hepatitis. HBV can resist immune system responses and often causes persistent chronic infections. HBV is the leading cause of liver cancer and cirrhosis. Interferons (IFNs) are cytokines with antiviral, immunomodulatory, and antitumor properties. IFNs are glycoproteins with a strong antiviral activity that plays an important role in adaptive and innate immune responses. They are classified into three categories (type I, II, and III) based on the structure of their cell-surface receptors. As an effective drug for controlling chronic viral infections, Type I IFNs are approved to be clinically used for the treatment of HBV infection. The therapeutic effect of interferon will be enhanced when combined with other drugs. IFNs play a biological function by inducing the expression of hundreds of IFN-stimulated genes (ISGs) in the host cells, which are responsible for the inhibiting of HBV replication, transcription, and other important processes. Animal models of HBV, such as chimpanzees, are also important tools for studying IFN treatment and ISG regulation. In the present review, we summarized the recent progress in IFN-HBV treatment and focused on its mechanism through the interaction between HBV and ISGs.

Tim-3 expression on peripheral monocytes and CD3+CD16/CD56+natural killer-like T cells in patients with chronic hepatitis B

Hepatitis B virus (HBV) infection is one of the major causes of chronic liver inflammation. Tim-3 acts as a negative regulatory molecule and plays a critical role in immune tolerance. In the current study, we investigated Tim-3 expression on peripheral monocytes and CD3+CD16/CD56+ natural killer like T (NKT-like) cells in chronic hepatitis B (CHB) patients. Peripheral blood mononuclear cells (PBMCs) were isolated from 52 CHB patients and 60 healthy controls. Tim-3+CD14+ cells and Tim-3+CD3+CD16/CD56+ cells were analyzed by flow cytometry. Results showed that expression of Tim-3 was significantly increased on both the monocytes and NKT-like cells in CHB patients than in controls (P = 0.002 and P < 0.001, respectively). Tim-3 levels on monocytes and NKT-like cells were further upregulated in patients with acute-on-chronic liver failure (ACLF). In addition, we assessed the correlation of Tim-3 expression with levels of alanine aminotransferase (ALT) and tumor necrosis factor alpha (TNF-α). Data revealed that Tim-3 expression on both monocytes and NKT-like cells was positively correlated with level of ALT (r = 0.59, P < 0.001, and r = 0.60, P < 0.001, respectively), whereas Tim-3 expression on NKT-like cells was negatively correlated with serum level of TNF-α (r = -0.54, P < 0.001) in CHB patients. Our results suggest that Tim-3 may play important roles in the pathogenesis of CHB.

Emerging pipeline drugs for hepatitis B infection

INTRODUCTION

Chronic hepatitis B virus (HBV) infection continues to represent a global health concern with an estimated 350 - 400 million people infected worldwide. Current treatment options are either of two IFN-based therapies or either of five oral nucleos(t)ide analogs which are used as monotherapy or in combination. Control of viral replication can be achieved basically in all patients today. However, despite the clinical efficacy of antivirals, long-term management remains a clinical challenge mainly due to the slow kinetics of HBsAg clearance. Emergence of viral resistance has been a challenge in the past with some but not all oral therapies. The development of novel therapeutic agents with different mechanisms of action might provide new opportunities to clear HBsAg and achieve HBsAg seroconversion which could be maintained off therapy. The long-term efficacy of combinations of IFN and/or nucleos(t)ide analogs might achieve antiviral synergy, preventing drug resistance and clearing viral covalently close circular DNA and infected cells.

AREAS COVERED

This article provides a review of recent data on the safety and efficacy of existing and emerging agents for the treatment of chronic hepatitis B infection.

EXPERT OPINION

Currently, entecavir and tenofovir offer a safe and effective treatment option for patients with chronic HBV with minimal to no resistance. Although entecavir and tenofovir are able to suppress replication in essentially all patients, achieving HBsAg seroconversion remains suboptimal among all antiviral therapy. There are a number of new therapies in the pipeline for the treatment of chronic HBV infection as well as revisiting IFN combined or sequential to antiviral therapy.