How to achieve immune control in chronic hepatitis B?

Chronic hepatitis B infection remains a major global health problem despite the existence of an effective vaccine. The current treatment options are either nucleos(t)ide analog therapy, which inhibits viral replication, or peginterferon-α, which has mainly immunomodulatory effects. However, treatment-induced HBeAg seroconversion with suppressed viral replication is mostly not sustainable, and loss of HBsAg is a rarely achieved endpoint. In addition, the hepatitis B virus persists in hepatocytes even after HBsAg clearance as covalently closed circular DNA is not eliminated from the hepatocytes. Because the course of chronic hepatitis B is determined by an ongoing interaction between the virus and the host immune system, immunomodulation may be the most logical approach in attempting to accomplish control or even cure of chronic hepatitis B. In the last years, methods for measuring the degree of immune control have been a major area of interest, with an important role for monitoring of HBsAg levels. In addition, new immunomodulatory agents are being developed and tested, providing promising options for future treatment.