持续性及慢性免疫性血小板减少症患儿DNA甲基转移酶mRNA的表达

Expression of DNA methyltransferase mRNA in children with persistent and chronic immune thrombocytopenia

目的 通过检测持续性及慢性免疫性血小板减少症（ITP）患JLOb周血淋巴细胞的DNA甲基转移酶（DNMTs）mRNA的表达水平，探讨DNA甲基化在儿童ITP发病机制中的作用。方法选取2014年1月至2015年1月在新乡医学院第一附属医院儿科病房治疗或随访的25例持续性及慢性ITP患儿和门诊体检健康的20例健康儿童（健康对照组）为研究对象。无菌采集其空腹外周血2mL，乙二胺四乙酸（EDTA）抗凝，分离单个核细胞，提取RNA，采用反转录一聚合酶链式反应（RT．PCR）方法检测DNMTl、DNMT3A、DNMT3BmRNA表达水平。结果1．持续性及慢性ITP患儿血小板（PLT）为（36．2-I-19．6）×10^9／L，明显低于健康对照组（168．8±46．8）×10^9／L，2组比较差异有统计学意义（t=-11．85，P=0．000）。2．持续性及慢性111P患JLDNMT1mRNA表达为0．17±0．05，明显低于健康对照组（0．27±0．10），2组比较差异有统计学意义（t=-3．912，P=0．001）；持续性及慢性111P患儿DNMT3AmRNA表达为0．20±0．10，明显低于健康对照组（0．32±0．11），2组比较差异有统计学意义（t=-3．779，P=0．000）；持续性及慢性ITP患儿DNMT3BmRNA表达为0．16±0．11，明显低于健康对照组（0．31±0．11），2者比较差异有统计学意义（t=-4．641，P=0．000）。3．DNMT1与DNMT3BmRNA表达呈正相关（r=0．433，P=0．031）；DNMT3A与DNMT3BmRNA表达呈正相关（r=0．721，P=0．000）。结论1．儿童持续性及慢性I，ITP存在DNMT1、DNMT3A、DNMT3BmRNA表达降低，提示DNA低甲基化可能参与儿童持续性及慢性ITP的发病机制。2．在儿童持续性及慢性ITP的DNA甲基化过程中DNMTs可能起协同作用．

Objective To discuss DNA methylation＇s effect on pathogenesis of pediatric immune thrombocyto- penia （ITP）through detecting the expression level of DNA methyltransferases （DNMTs）mRNA in peripheral blood lymphocytes of children with ITP. Methods Two mL peripheral blood was collected from each of 25 children with persistent and chronic ITP and 20 healthy children （ the healthy control group） by using aseptic method in the pediatric ward of the First Affihated Hospital of Xinxiang Medical University from January 2014 to January 2015. First ethylene diamine tetraacetic acid （EDTA） was used as the anticoagulant. Then separate the mononuclear cells, extract RNA and detect expression levels of DNMT1, DNMT3A and DNMT3B mRNA using reverse transcription -polymerase chain reaction （ RT - PCR） method. Results （ 1 ） The blood platelet （PLT） of children with persistent and chronic ITP was （36. 2 ± 19. 6） × 10^9/L,which was obviously lower than the healthy control group（ 168.8 ±46.8） × 10^9/L（t = - 11.85, P =0. 000）. （2）The DNMT1 mRNA expression level of children with persistent and chronic 1TP was 0.17 ± 0. 05, which was obviously lower than the healthy control group （0.27 ± 0.10） （ t = - 3. 912 ,P = 0. 001 ）. The DNMT3A mRNA expression level of children with persistent and chronic ITP was 0.20± 0.10, which was obviously lower than the healthy control group （0.32 ±0.11 ） （t = -3. 779,P =0.000）. The DNMT3B mRNA expression level of children with persistent and chronic ITP was 0.16 ± 0.11 ,which was obviously lower than the healthy control group （0.31 ± 0. 11 ） （ t = - 4.641, P = 0.000）. （3） There was positive correlation between the expression of DNMT1 and DNMT3B mRNA（r = 0. 433, P = 0. 031 ）. There was positive correlation between the expression of DNMT3A and DNMT3B mRNA （ r = 0. 721, P = 0. 000）. Conclusions （ 1 ） Children with persistent and chronic ITP have lower expression levels of DNMT1, DNMT3A, DNMT3 B mRNA, which indicates that DNA methylation contributes to the pathogenesis of pediatric persistent and chronic ITP. （2） DNMTs have synergistic effect on DNA methylation of pediatric persistent and chronic ITP.