The immune effects of rituximab on dendritic cells derived from patients with primary immune thrombocytopenia / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the changes of surface antigen and function of rituximab on dendritic cells derived from patients with Primary immune thrombocytopenia (ITP) to further understand the effective mechanism of immunotherapy.</p><p><b>METHODS</b>The peripheral blood mononuclear cells (PBMCs) were isolated from remission patients with ITP before and after low-dose rituximab infusion, and the PMNCs were stimulated for 5 days by rhGM-CSF and rhlL-4 in 5% CO2 air at 37°C incubator. Then all of DCs were cultured with TNF-α for 48 hours. The morphology of DCs was monitored under inverted microscope daily, and the surface antigens of the DCs were analysed by flow cytometry, meanwhile the levels of IL-12p70 and TGF-β1 in supernatants were detected by ELISA, mix lymphocyte reaction was performed by MTT assay.</p><p><b>RESULTS</b>(1) Rituximab-treated-DCs showed no obvious tree-like protruding compared with untreated-DCs. The former cells were small and most of nucleus were centric. (2) The expressions of HLA-DR, CD80, CD83 and CD86 on rituximab-treated-DCs \[56.37 ± 3.95)%, (36.41 ± 2.82)%, (30.45 ± 4.61)% and (41.98 ± 4.17)%, respectively\] were significantly lower than those untreated-DCs \[(73.71 ± 7.61)%, (55.14 ± 7.30)%, (80.91 ± 7.09)% and (59.03 ± 3.43)%, respectively\](all P < 0.05), the concentration of IL-12p70 was significantly lower, \[(66.87 ± 4.29)% vs (50.17 ± 14.52)%\], while that of TGF-β1 \[(9.70 ± 0.31)%\] higher than the untreated-DCs \[(2.70 ± 0.36)%\] (P < 0.05). (3) The abilities to activate T cells proliferation of rituximab-treated-DCs reduced compared with untreated-DCs.</p><p><b>CONCLUSION</b>The surface antigen of ITP-DCs and the concentration of IL-12p70 reduced after the low-dose rituximab infusion. The abilities to activate T cells proliferation reduced while the concentration of TGF-β1 increased. Rituximab may achieve its therapeutic effect on ITP by downregulating the immunoreactivity of DCs.</p>

Induction of anti-leukemic immunity of dendritic cells derived from multidrug resistant leukemia K562/A02 cells with high expression of P-glycoprotein and sensitive K562 cells / 中国实验血液学杂志

This study was aimed to investigate and compare the anti-leukemic effect mediated by dendritic cells (DC) derived from multidrug resistant (MDR) leukemia K562/A02 cells with high expression of p-glycoprotein (P-gp) and sensitive K562 cells. Multidrug resistant K562/A02 cell line and sensitive K562 cell line from chronic myeloid leukemia (CML) were induced for differentiating to DC in complete RPMI 1640 culture medium supplemented with GM-CSF (1 000 U/ml), IL-4 (500 U/ml) and TNF-alpha (100 ng/ml) for 14 days. The morphologic features of DC were observed by means of optical microscopy and the phenotype of DC was detected by flow cytometry. T-cell stimulating activity was determined by allogeneic lymphocyte reaction (allo-MLR). Cytotoxic activity was measured by MTT assay. The results indicated that DC derived from K562/A02 cells and K562 cells similarly showed the typical morphology of dendritic cell and expressed the surface differentiation antigens and costimulatory molecules CD1a, CD83, HLA-DR, CD80 and CD86 of DC. In allo-MLR, K562/A02-DC had a higher capacity to induce lymphocyte proliferation, compared with K562-DC (P < 0.05). K562/A02-DC and K562-DC could similarly generate specific cytotoxic activity against K562/A02 cells or K562 cells respectively, but low reactivity against HL-60 cells. More importantly, the cytotoxic activity mediated by K562/A02-DC was stronger than that by K562-DC against K562/A02 cells or HL-60/VCR cells (P < 0.01, respectively). It is concluded that functional DC can be differentiated from multidrug resistant leukemia K562/A02 cells as well as sensitive K562 cells in the presence of GM-CSF, IL-4 and TNF-alpha. Especially, DC derived from K562/A02 cells can induced a p-glycoprotein specific anti-leukemic immunity.