Combination Therapy with Antiviral Drugs and Hepatitis B Vaccine in Incidentally-Detected and Asymptomatic Chronic Hepatitis Virus B Carriers at Bangladesh

Hepatitis B (HB) immunoglobulin plus HB vaccine for intrauterine HB virus infection

BACKGROUND

Vaccination against hepatitis B virus (HBV) infection in infants born to hepatitis B surface antigen (HBsAg)-positive mothers using HB immunoglobulin (HBIG) and hepatitis B (HB) vaccine was launched in Japan in 1985. Infants testing positive for HBsAg at 1 month of age are considered to have prenatally acquired the infection and are usually excluded from the prevention program. Infants born to HB e antigen (HBeAg)-positive mothers are at a high risk of perinatally acquiring the infection. In this study, long-term outcome was evaluated in children with prenatal HBV infection who received the HBIG and HB vaccine in Japan.

METHODS

Newborns of both HBsAg- and HBeAg-positive carrier mothers received HBIG within 48 h of birth and at 2 months of age. Subsequently, three doses of recombinant HB vaccine were given at 2, 3, and 5 months of age. Outcome was compared between the following two groups: infants who completed the vaccination program, even if they were HBsAg positive at 1 month of age (n = 15), and infants who did not (n = 51).

RESULTS

Seroconversion from HBeAg to anti-HBe antibody (HBeAb) before 3 years of age was observed in five children (33%) who completed the vaccination program and in two (4%) who did not (P = 0.005). In 2/5 children who completed the vaccination program and achieved HBeAb seroconversion, seroconversion from HBsAg to anti-HBs antibody was also noted.

CONCLUSION

This specific vaccination program for children with prenatal HBV infection has the potential to alter immune tolerance to HBV.

Epidemiology of Viral Hepatitis and Liver Diseases in Bangladesh

Bangladesh is a South Asian country with a homogeneous population. However, some difference has been demonstrated in the distribution of liver disease in different parts of the country. Hepatitis E remains the principal cause of acute hepatitis in Bangladesh, while chronic liver disease in Bangladesh, including hepatocelullar carcinoma, is predominantly due to hepatitis B virus. Hepatitis B has been extensively studied and characterized in Bangladesh, and some major clinical trials with HBV-related antigens have also been conducted.

T cell immunopathogenesis and immunotherapeutic strategies for chronic hepatitis B virus infection

Hepatitis B is caused by the host immune response and T cells play a major role in the immunopathogenesis. More importantly, T cells not only destroy hepatocytes infected by hepatitis B virus (HBV), but also control HBV replication or eradicate HBV in a noncytolytic manner. Therefore, analysis of T cell immune response during acute and chronic HBV infection is important to develop a strategy for successful viral control, which could lead to immunotherapy for terminating persistent HBV infection. There have been many attempts at immunotherapy for chronic HBV infection, and some have shown promising results. High viral load has been shown to suppress antiviral immune responses and immunoinhibitory signals have been recently elucidated, therefore, viral suppression by nucleos(t)ide analogs, stimulation of antiviral immune response, and suppression of the immunoinhibitory signals must be combined to achieve desirable antiviral effects.

Therapeutic vaccines and immune-based therapies for the treatment of chronic hepatitis B: perspectives and challenges

The treatment of chronic hepatitis B virus (HBV) infection has greatly improved over the last 10 years, but alternative treatments are still needed. Therapeutic vaccination is a promising new strategy for controlling chronic infection. However, this approach has not been as successful as initially anticipated for chronic hepatitis B. General impairment of the immune responses generated during persistent HBV infection, with exhausted T cells not responding correctly to therapeutic vaccination, is probably responsible for the poor clinical responses observed to date. Intensive research efforts are now focusing on increasing the efficacy of therapeutic vaccination without causing liver disease. Here we describe new approaches to use with therapeutic vaccination, in order to overcome the inhibitory mechanisms impairing immune responses. We also describe innovative strategies for generating functional immune responses and inducing sustained control of this persistent infection.