大剂量地塞米松对免疫性血小板减少性紫癜患者浆样树突状细胞功能及Toll样受体9表达的影响

Effect of high-dose dexamethasone on the function and TLR-9 expression of plasmacytoid dendritic cells in patients with immune thrombocytopenic purpura

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40mg/d,连用4d。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24h,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TLR9mRNA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TLR9mRNA的表达水平高于正常对照组(P<0.05);治疗后pDCs的TLR9mRNA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。

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 pa tients with immune thrombocytopenic purpura received high dose（HD）DXM at single daily doses of 40 mg for 4 consecu rive days. The peripheral blood plasmacytoid dendritic cells isolated from 13 remission patients and 15 normal controls were separa＊ed by immunomagnetie beads and then induced by Cp（~OND2216 for 24 hours. The levels of IFN-α,IL-6 and TNF-α in 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 c,, 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 IFNa, IL6 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 re duced,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 TLRg,inhibit pDC function,and thus play a therapeutic role.