Expanded Circulating Follicular Dendritic Cells Facilitate Immune Responses in Chronic HBV Infection
Abstract Background: Restoration of host hepatitis B virus (HBV)-specific antiviral immunity is an effective strategy for hepatitis B recovery. Follicular dendritic cells (FDCs) play a crucial role in immune regulation. This study aims to investigate the characteristics and functions of FDCs in chronic HBV infection. Methods: The frequencies of FDCs in peripheral blood, liver, and spleen were measured in patients with chronic HBV infection. Isolated FDCs from splenic tissues of HBV-related liver cirrhosis-induced hypersplenism patients were cultured with autologous intrasplenic CD4+ T cells and CD19+ B cells. Results: We found that patients with chronic HBV infection had a significantly increased frequency of circulating FDCs compared with that of healthy controls. Additionally, the frequency of circulating FDCs was positively correlated with that of intrahepatic and intrasplenic counterparts. Moreover, a positive correlation between the frequency of circulating FDCs and plasmablast and memory B cells, as well as C-X-C motif chemokine receptor type 5 (CXCR5)+CD4+ T cells and CXCR5+CD8+ T cells was also observed. Notably, in vitro experiments demonstrated that FDCs derived from splenic tissues of chronic HBV patients facilitated interferon-γ and interleukin-21 production from autologous intrasplenic CD4+ T cells and promoted the proliferation of autologous intrasplenic CD19+ B cells.Conclusions: Expanded FDCs in patients with chronic HBV infection may favor the host immune responses against HBV. The identification of this unique population may contribute to a better understanding of the immune regulatory mechanisms and provide a potential immunotherapeutic target in chronic HBV infection.