Objective To investigate the relationship between dendritic cell (DC)and intestinal endotoxemia in patients with chronic hepatitis B (CHB).Methods Peripheral blood were collected from CHB patients (n = 80)and healthy controls (n = 21 ).Plasma endotoxin (ET)levels,liver function (alanine transaminase,total bilirubin)were detected.According to plasma ET concentration,all CHB patients were divided into two groups:ET positive and ET negative.The peripheral blood mononuclear cells (PBMCs)were isolated and then cultured with recombinant human granulocyte-macrophage colony-stimulating factor ( rhGM-CSF),recombinant human interleukin-4 ( rhIL-4 ),FMS-related tyrosine kinase 3 ligand (Flt3L)and tumor necrosis factor-alpha (TNF-α)to derive DC.The phenotypic patterns were characterized by flow cytometry.The proliferation of T lymphocytes was evaluated with mixed leukocytes reaction (MLR)and the levels of IL-12 and interferon-γ (IFN-γ)produced by DC were analyzed with enzyme-linked immunosorbent assay (ELISA).Comparisons among the two groups and healthy control group were done by single factor analysis of variance.Results Compared to healthy controls,the expressions of CD83,CD80,CD86,human leucocyte antigen (HLA)-DR and the proliferation of allogeneic T lymphocytes by DC were all significantly reduced in CHB patient groups.The expressions of CD83,CD80,CD86,HLA-DR and the activation of proliferation in ET positive subjects were lower than those in ET negative subjects [CD83 (8.25±3.63)% vs(11.39±4.35)% ,CD80 (10.63±4.52)% vs (13.56±5.13)%,CD86 (36.61±16.16)% vs (45.90±15.35)%,HLA-DR (61.65±14.33)% vs (70.35±18.89)%,the activation of proliferation0.812±0.311 vs 1.153±0.324; F=5.123,4.213,3.714,3.323 and 3.125,respectively; all P＜0.05].After cultured for 9 days,the secretions of IL-12 and IFN-γ by DC were significantly lower in CHB patients than in healthy controls [IL-12 (16.99± 6.74)pg/mL vs (44.51±14.56)pg/mL,IFN-γ (10.52±4.19)pg/mL vs (17.94±5.86)pg/mL].The level of IL-12 in the ET positive group was significantly lower than that ET negative group [( 13.14 ±5.71)pg/mL vs (20.98 ± 9.03)pg/mL; F= 3.225,P = 0.016].The level of IFN-γ was not different between two groups [(9.46 ± 3.24)pg/mL vs (11.54 ± 5.20)pg/mL; F = 2.003,P =0.076].Conclusion The intestinal endotoxemia may play a role in DC dysfunction in CHB patients.