DNA甲基转移酶在儿童免疫性血小板减少症中的蛋白表达

The protein expression of DNA methyltransferase in children with immune thrombocytopenia

目的通过检测DNA甲基转移酶(DNMTs)在儿童免疫性血小板减少症(ITP)外周血中蛋白水平的表达,探讨其与儿童ITP的发病机制的关系。方法收集2015年5月-2016年5月在新乡医学院第一附属医院门诊、病房就诊和治疗的60例新诊断ITP患儿(实验组)和门诊健康体检的36例儿童(对照组)为研究对象。无菌采集其空腹外周血2 mL,采取酶联免疫吸附法检测血清中DNMT1、DNMT3a、DNMT3b的蛋白表达水平。分别分析年龄、性别、血小板计数(PLT)对血清DNMT1、DNMT3a、DNMT3b的影响,及DNMT1、DNMT3a、DNMT3b三者之间的关系。结果 (1)新诊断ITP患儿PLT为(21.3±26.1)×10~9/L,明显低于健康对照组(261.2±78.4)×10~9/L,差异有显著性(t=-17.777,P=0.000)。(2)ITP患儿DNMT1、DNMT3a、DNMT3b(ug/L)的蛋白表达水平分别为(1.43±0.96)、(0.67±0.39)、(0.53±0.39),明显低于对照组(2.05±1.24)、(1.04±0.58)、(0.73±0.45),差异有显著性(t=-2.547,-3.692,-2.341;P=0.013,0.000,0.021)。经Person相关性分析,ITP患儿血小板计数与DNMT1、DNMT3a、DNMT3b的蛋白表达水平无明显相关性(r=-0.062、0.161、0.079,P=0.636、0.220、0.549)。DNMT1与DNMT3a、DNMT3b的蛋白表达无相关性(r=-0.025,-0.057;P=0.851、0.665),DNMT3a、3b的蛋白表达正相关性(r=0.259,P=0.046)。结论新诊断ITP患儿外周血中DNMT1、DNMT3a、DNMT3b的蛋白表达水平显著降低,提示DNA甲基转移酶的异常表达可能与儿童ITP的发病机制相关,推测在儿童ITP患儿DNA甲基化过程中,DNMT3a、DNMT3b起着相互协调的作用。

Objective To explore the relationship between DNA methyltransferase（DNMTs） and pathogenesis of childhood immune thrombocytopenia（ITP） by detecting the protein expression level of DNMTs in serum of the children with ITP. Methods Two mL peripheral blood was collected from 60 children with newly diagnosed ITP（experimental group） in outpatient and ward and 36 healthy children（the healthy control group） respectively by aseptic operation in the First Affiliated Hospital of Xinxiang Medical University from May 2015 to May 2016. Enzyme-linked immunosorbent assay（ELISA） method was used to measure the protein expressions of DNMTl,DNMT3 a and DNMT3 b in peripheral blood. The impact of age,genderand platelet count on serum DNMT1,DNMT3 a and DNMT3 b were analyzed among them.Results ① The blood platelet（PLT） of children with newly diagnosed ITP was（21.3±26. 1） x 109/L,which was significantly lower than the healthy control group（261. 2 ±78. 4） ×10^9/L（t=-17. 777,P=0.000）.② The protein expression levels of DNMT1,DNMT3 a and DNMT3 b（μg/L） of children with newly diagnosed ITP were（ 1. 43 ± 0. 96）,（0.67 ± 0. 39）,（ 0. 53 ± 0. 39）,which were significantly lower than the healthy control group（2. 05 ±1.24）,（1. 04 ±0. 58）,（0. 73 ±0. 45）（t =-2. 547,-3. 692,-2. 341;P=0. 013,0. 000,0. 021）. Person correlation analysis showed that there was no significant correlation between platelet levels and DNMT1, DNMT3 a, DNMT3 b protein levels in children with ITP（r =-0.062,0. 161,0.079, P = 0.636, 0.220, 0.549）,and among the protein expression of DNMT1, DNMT3 a and DNMT3 b（r=-0.025,-0. 057;P =0. 851,0.665）. There was positive correlation between the expression of DNMT3 a and DNMT3 b（ r =0. 259, P =0. 046）.Conclusions The protein expression levels of DNMT1, DNMT3 a and DNMT3 b in serum of newly diagnosed children with ITP were significantly decreased, suggesting that the aberrant expression of DNA methyltransferase may be associated with the pathogenesis of childhood ITP. DNMT3 a, DNMT3 b plays a coordinating role in the process of DNA methylation in children with ITP.