Efficacy of extracorporeal immunoadsorption therapy for removal of HBsAg

The purpose of chronic hepatitis B (CHB) treatment is functional cure (FC). It refers to the removal of hepatitis B surface antigen (HBsAg) from the serum. However, this outcome is rare with current treatments due to the presence of integrated hepatitis B virus (HBV) DNA and intrahepatic covalently closed circular DNA (cccDNA). This study investigates the efficacy of removal of HBsAg using immunoadsorption. An immunosorbent was prepared by coupling anti-HBsAg monoclonal antibodies to agarose beads, selected from six candidates based on adsorption efficiency. Then the adsorbents were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). V79 lung fibroblasts were used to determine the cytotoxicity of the immunosorbent through in vitro viability assays. The results indicated that the immunosorbent was non-cytotoxic. Static and dynamic adsorption studies in vitro demonstrated efficient HBsAg removal. To validate therapeutic potential, an extracorporeal circulation system equipped with the immunosorbent (10 ml sorbent column) was tested in rabbits injected with HBsAg-positive rabbit serum. This system selectively reduced serum HBsAg levels by 76.38 ± 1.37% and HBV DNA by 66.20 ± 0.85%. Given the absence of existing therapies capable of reducing HBsAg directly, our findings suggest that combining immunoadsorption with HBV drugs may serve as a novel therapeutic strategy—or at least provide a valuable adjunct—to advance functional cure efforts in CHB. Further clinical validation is warranted.