Safety and immunogenicity of hepatitis B surface antigen-pulsed dendritic cells in patients with chronic hepatitis B.

The immune modulator capacity of antigen-pulsed dendritic cells (DC) has been documented in patients with cancers and in animal models of chronic viral infections. Cancer antigen-pulsed DC are now used for treating patients with cancer. But viral antigen-pulsed DC are not used in chronic viral-infected patients because safety of antigen-pulsed DC has not been evaluated in these patients. DC were isolated from human peripheral blood mononuclear cells by culturing with human-grade granulocyte-macrophage colony stimulating factor and interleukin-4. Human blood DC were cultured with hepatitis B surface antigen (HBsAg) for 8h to prepare HBsAg-pulsed DC. After immunogenicity assessment of HBsAg-pulsed DC in vitro, five million HBsAg-pulsed DC were administered intradermally to five patients with chronic hepatitis B (CHB) 1-3 times. HBsAg-pulsed DC were immunogenic in nature because they produced significantly higher levels of interleukin-12 and interferon-γ compared to unpulsed DC (P<0.05). Also, HBsAg-pulsed DC induced proliferation of HBsAg-specific T lymphocytes in vitro. CHB patients injected with HBsAg-pulsed DC did not exhibit generalized inflammation, exacerbation of liver damage, abnormal kidney function, or features of autoimmunity. Administration of HBsAg-pulsed DC induced anti-HBs in two patients and HBsAg-specific cellular immunity in 1 patient. This is the first study about preparation of antigen-pulsed DC using human consumable materials for treating patients with CHB. Because HBsAg-pulsed DC were safe for all patients with CHB and had immune modulation capacity in some patients, phase I and phase II clinical trials with antigen-pulsed DC in CHB and other chronic infections are warranted.