Characteristics of impaired dendritic cell function in patients with hepatitis B virus infection

Dendritic cells are antigen-presenting cells with a central role in host immune response. This study analyzed gene expression and dendritic cell function in hepatitis B virus (HBV) patients and functions impaired due to HBV, and identified the genes related to these functions. Peripheral blood mononuclear cells from 23 HBV patients and 9 healthy controls were utilized. Mononuclear cells were isolated from side-scatter and forward-scatter gating using fluorescence-activated cell sorting (FACS), the lineage-negative HLA-DR-positive fraction was extracted, and was further divided into CD123-positive plasmacytoid DCs (pDCs) and CD11c-positive myeloid DCs (mDCs). Cell sorting was performed, and the number of DCs was measured and surface markers were analyzed. After cell sorting, CD11c and CD11b expression levels in the pDC and mDC fractions were confirmed using real-time PCR. RNA was extracted from sorted pDCs and subjected to gene expression analysis using Affymetrix Human 133U Plus 2.0 gene chip. In chronic HBV infection, many abnormalities in immune function, such as decline in cytotoxic T lymphocyte (CTL) function, increase in regulatory T cells, abnormal dendritic cell DC function, and abnormal natural killer cell function have been reported. However, other causes of DC functional decline in HBV infection, and molecules involved in the decline remain unclear. The present study aimed to analyze gene expression and DC function in HBV patients, and to identify the functions that are reduced compared with healthy individuals, as well as the molecules associated with these reduced functions.