Abstract： Objective To explore the roles of interleukin (IL)-10 differentiated peripheral blood monocyte-derived dendritic cell (DC-10) of allergic asthma patients in T-lymphocytes proliferation in vitro.Methods From January to June 2011,10 subjects with dust mite allergic asthma treated at Third Affiliated Hospital of Soochow University were enrolled.Their peripheral blood monocytes were isolated by FicollHypaque solution density gradient centrifugation and adherent method.And the adherent monocytes were routinely cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) + interleukin-4 (IL-4) + tumor necrosis factor-alpha (TNF-α),stimulated with/without interleukin-10 (IL-10),pulsed with dust mite allergen and finally harvested.The cell surface molecules including CD80,CD83,CD86,human leukocyte antigen (HLA)-DR and immunoglobulin-like transcript 2 (ILT2) were detected by immunofluorescent labeling and flow cytometry.And cellular functions were estimated by detecting the capacities of DC uptake antigens with fluorescein isothiocyanate (FITC)-dextran capturing assay.The IL-10differentiation DC (DC-10) were cultured with autologous peripheral T cells (DC-10 group),either alone (DC-TNF group) or together (combined group) with autologous immunostimulatory DC (DC-TNF).And the impact of this treatment on T-cell responses was assessed for each donor by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay.The production of interferon-γ (IFN-γ),IL-4,interleukin-5 (IL-5) and interleukin-13 (IL-13) were measured with the quantification of enzyme linked immunosorbent assay (ELISA) kits.Results In DC-10,the levels of some mature DC's markers (CD80,CD83,CD86 & HLA-DR) decreased,ILT2 increased and there were the higher capacities of up-taking FITC-dextran particle (72.32％ ±2.93％ vs 54.41％ ± 2.95％,P ＜ 0.01).Compared with the DC-TNF group (1.74 ± 0.15),the T cell proliferation of the DC-10 group (1.06 ± 0.18) and that of the combined group (1.34±0.16) were significantly inhibited (P ＜0.01).The secretion levels of IFN-γ,IL-4,IL-5 and IL-10 were (2998 ± 141),(157 ± 17),(2608 ± 254) and (55 ± 11) ng/L in the DC-10 group versus (3223 ±203),(149 ± 19),(2465 ± 183) and (88 ± 10) ng/L respectively in the combined group.They were all significantly reduced versus (3639 ±209),(173 ± 16),(2771 ± 183) and (127 ± 11) ng/L in the DC-TNF group (all P ＜ 0.01).Conclusions The IL-10-treated human DC may express a tolerogenic phenotype and induce the allergen tolerance of T cells.And the induction of DC-10 represents a promising target for therapeutic intervention of effectively managing the clinical outcomes of allergic asthma.