Hepatitis B surface antigen and functional cure of chronic hepatitis B / 复旦学报（医学版）

ABSTRACT

Functional cure of viral hepatitis B is currently the main target of scientists worldwide.The definition of functional cure is durable loss of HBsAg (with or without HBsAg sero-conversion),undetectable serum HBV DNA,persistence of cccDNA in an inactive state and the absence of spontaneous relapse after treatment cessation.In this article,the knowns and unknowns of HBsAg have been shortly reviewed,and current immunotherapies for chronic hepatitis are introduced.Among these,the experimental and clinical application of HBsAg-HBIG immunotherapy developed by our group is presented.Based on the current data,as anti-HBV drugs can eliminate or decrease viral load,neutralizing HBsAg antibody can provide passive immunity,and HBsAg-HBIG complexes can trigger potent immune responses,a "sandwich" protocol for functional cure of chronic hepatitis B is proposed.Namely,first use anti-HBV drugs for decrease or elimination of viral load;second,use passive immune therapy,by neutralizing anti-HBs antibody for decrease or clearance of serum HBsAg;and lastly,use active immunization,by HBsAg-HBIG complex vaccination to induce long term and effective immune responses to HBsAg.This approach may keep cccDNA in an inactive state,and reach the goal of functional cure.