Effect of high-dose dexamethasone on the function and TLR-9 expression of plasmacytoid dendritic cells in patients with immune thrombocytopenic purpura
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摘要: 目的:研究大剂量地塞米松对免疫性血小板减少性紫癜(ITP)患者浆样树突状细胞(pDCs)功能及Toll样受体9表达的影响。方法:15例初诊的ITP患者给予地塞米松40 mg/d,连用4 d。采用免疫磁珠分离法体外分离15例正常对照及13例治疗有效患者治疗前后外周血中浆细胞样树突状细胞(pDCs),用CPG-ODN 2216刺激外周血pDCs并与之共培养24 h,采用酶标记免疫吸附(ELISA)方法检测上清中IFN-α、IL-6、TNF-α的含量;实时定量聚合酶链反应(RT-PCR)检测pDCs的TLR9 mRNA表达量。结果:①治疗前pDCs产生IFN-α、IL-6、TNF-α细胞因子的水平[(960.83±164.65)pg/ml,(156.15±39.89)pg/ml,(137.31±35.44)pg/ml]明显高于正常对照组[(616.67±105.98)pg/ml,(89.13±21.48)pg/ml,(88.53±25.81)pg/ml)](P<0.05);治疗后pDCs产生IFN-α、IL-6、TNF-α细胞因子水平分别降至(678.46±128.88)pg/ml、(97.77±26.31)pg/ml、(103.08±26.42)pg/ml,与治疗前比较差异有统计学意(P<0.05),与正常对照组比较,差异无统计学意义(P>0.05)。②治疗前pDCs的TLR9 mRNA的表达水平高于正常对照组(P<0.05);治疗后pDCs的TLR9 mRNA的表达水平低于治疗前(P<0.05),但与正常对照组的表达水平比较,差异无统计学意义(P>0.05)。结论:pDCs分泌的细胞因子及其表达的TLR9在ITP发病中起重要作用;地塞米松可能通过下调TLR9的表达,抑制pDCs分泌细胞因子的功能,从而对ITP起到治疗作用。
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关键词:
- 免疫性血小板减少性紫癜 /
- 浆细胞样树突状细胞 /
- 地塞米松 /
- Toll样受体9 /
- 细胞因子
Abstract: Objective:To investigate the effect of high-dose dexamethasone on the function and TLR-9 expression of plasmacytoid dendritic cells in the patients with immune thrombocytopenic purpura.Method:Fifteen newly diagnosed patients with immune thrombocytopenic purpura received high dose(HD)DXM at single daily doses of 40 mg for 4 consecutive days.The peripheral blood plasmacytoid dendritic cells isolated from 13 remission patients and 15 normal controls were separated by immunomagnetie beads and then induced by CpG-OND2216 for 24 hours.The levels of IFN-α,IL-6 and TNF-αin the supernatant were detected by enzyme linked immunosorbent assay.The expression of TLR9 mRNA of pDCs was detected by Real-time quantitative PCR.Result:In ITP patients, the levels of IFN-α,IL-6 and TNF-αproduced by pDCs were significantly higher compared with those in normal controls and in treated group(P<0.05).After HD DXM treatment,the levels of IFN-α,IL-6 and TNF-α were decreased significantly without significant difference between HD-DXM treatment patients and normal controls(P>0.05).The expression of TLR9 mRNA of pDCs in untreated group were significantly higher than control group(P<0.05).TLR9 mRNA level of pDCs in treated group was significantly reduced,without significant difference from that in control group(P>0.05).Conclusion:pDCs may play important role in ITP by their Toll-like receptor 9 and cytokines secretion;Dexamethasone may reduce the expression of TLR9,inhibit pDC function,and thus play a therapeutic role. -
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