摘要
目的从DNA甲基化角度探讨成人特发性血小板减少性紫癜（ITP）的发病机制。方法应用SYBRGreen实时定量PCR方法测定48例成人ITP患者与36例正常对照者外周血单个核细胞DNA甲基转移酶1（DNMT1）、DNA甲基转移酶3A（DNMT3A）和DNA甲基转移酶3B（DNMT3B）的mRNA的相对表达水平。采用反相高效液相技术（HPLC）检测ITP患者与正常对照血浆中S-腺苷蛋氨酸（SAM）和S-腺苷同型半胱氨酸（SAH）含量。运用流式细胞术检测ITP患者与正常对照外周血CD4＋和CD8＋T细胞表面淋巴细胞功能相关抗原-1（LFA-1）亚单位CD11a的表达水平。结果成人ITP患者外周血单个核细胞DNMT3A和DNMT3BmRNA表达水平较对照组减低（P〈0．01）；DNMT1mRNA表达水平与对照组相比有降低趋势，但差异无统计学意义（P〉0．05）。成人ITP患者血浆SAH与对照组相比增高，差异有统计学意义（P〈0．05）；而血浆SAM和SAM／SAH比率与正常对照组相比差异无统计学意义（P值均〉0．05）。成人ITP患者外周血CD4＋＋CD11a＋细胞比例显著高于对照组（P〈0．01），而CD4＋CD11a＋细胞比例和CD4CD11a＋／CD8＋CD11a比率较对照组显著降低（P值均〈0．01），差异有统计学意义。结论成人ITP患者外周血存在淋巴细胞低甲基化状态以及T细胞亚型上存在异常的CD11a／LFA-1表达。DNA甲基化可能在ITP的发病中起一定的作用，但确切的作用机制还有待于进一步深入研究。
Objective To explore the role of DNA methylation in pathogenesis of adult idiopathic thrombocytopenic purpura （ITP）. Methods We measured DNA methyhransferases （DNMTs） 1, 3A and 3B mRNA expression in peripheral blood momouclear cells of 48 adult ITP patients and 36 normal controls using real-time polymerase chain reaction, as well as the plasma levels of S-adenosylmethionine （SAM） and S-adenosylhomocysteine （SAH） with reversed phase high performance liquid chromatography （HPLC）. Furthermore, we determined the expression of CD11JLFA-1 on CD4＋ or CDs T cells by three-color flow cytometry. Results The mRNA expression of two DNA methyltransferases （DNMT3A and DNMT3B ） was significantly lower when comparing ITP patients with healthy controls （ P 〈 0.01 ）. Although there were decreased tendency when comparing expression of DNMT1 of ITP patients with healthy controls, no significant differences were found （ P 〉 0. 05 ）. The SAH concentration in the plasma of ITP patients was significantly elevated than that in the healthy controls （ P 〈 0. 05）. However we found significant differences of SAM and SAM/SAH ratio in the plasma of ITP patients when compared with the healthy subjects （ both P 〉 0. 05 ）. In addition, CD11a/LFA-1 expression on CD6＋ T lymphocytes increased in ITP patients compared with the control , ＋ D ＋ CD8＋ ratio group（P 〈0. 01） whereas CD11a/LFA-1 expression on CD4＋ T lymphoeytes and CD＋ CD11a/ CD8＋ was significantly decreased in ITP patients than that in control group （both P 〈 0. 01 ）. Conclusion Aberrant DNA methylation in peripheral blood and CD11a/LFA-1 expression on T cell surface may play animportant role in the pathogenesis of ITP, although the underlying mechanisms still await further investigation.
出处
《中华内科杂志》
CAS
CSCD
北大核心
2010年第3期208-212,共5页
Chinese Journal of Internal Medicine
