中文摘要：

目的探讨骨髓增生异常综合征（MDS）患者骨髓CD3＋T细胞TET2及DLK1基因的表达水平及其临床意义，为进一步阐明MDS细胞免疫异常的机制提供依据。方法应用免疫磁珠分选骨髓CD3＋T细胞，应用实时荧光定量PCR（qPCR）检测26例MDS患者和16例正常对照骨髓CD3＋T细胞中TET2和DLK1mRNA的表达水平，分析它们与临床特征之间的相关性。结果MDS患者骨髓CD3＋T细胞中TET2mRNA表达是正常对照组的（0．16±0．15）倍（P〈0．01）；TET2mRNA表达水平与血清补体C3呈显著正相关（r=0．404，P〈0．05）；MDS患者骨髓CD3＋T细胞中DLKlmRNA表达是正常对照组的（1．61±0．88）倍（P〈0．05）；依据染色体分组，染色体异常组DLK1表达水平是染色体正常对照组的（1．45±0．44）倍（P〈0．05）；DLK1mRNA表达水平与骨髓原始细胞比例呈显著正相关（r=0．343，P〈0．05）。结论MDS患者骨髓CD3＋T细胞中TET2mRNA表达降低，DLK1mRNA表达增高，提示CD3T细胞有质的异常，这可能是导致机体免疫监视功能下降的机制之一。

英文摘要：

Objective To investigate the expression of TET2 and DLK1 mRNA in bone marrow CD3＋ T cells of patients with myelodysplastic syndrome （MDS） and their clinical significance and to explore the potential mechanism of abnormal cell-mediated immunity. Methods CD3＋ T cells were sorted by magnetic activated cell-sorting system. The expressions of TET2 and DLK1 mRNA in bone marrow CD3＋ T cells from 26 MDS patients and 16 healthy controls were detected by fluorescence quantitative PCR. Results The expression of TET2 mRNA in CD; T cells was down-regulated in the MDS patients by （0. 16 ＋0. 15 ） fold compared with the controls （ P 〈 0. 05 ）. The expression of TET2 mRNA in CD3＋ T cells of MDS patients was positively correlated with serum complement C3 （ r = 0. 404 ,P 〈 0. 05 ）. The expression of DLK1 mRNA in CD3＋ T ceils was up-regulated in the MDS patients by （ 1.61 ± 0. 88 ） folds compared with the controls （P〈0. 05）. Grouped by the chromosomes, the patients with chromosome abnormalities presented significantly higher DLK1 mRNA level than those with normal chromosomes [ （ 1.45 ±0. 44 ） folds, P 〈 0. 051. The expression of DLK1 mRNA in CD3＋ T cells of MDS patients was positively correlated with the proportion of bone marrow blasts （ r = 0. 343, P 〈 0. 05 ）. Conclusions The mRNA expression of TET2 in CD3＋ T cells of MDS patients was decreased while the mRNA expression of DLK1 was increased, which might decline the immune surveillance function. The findings would be useful for exploring the mechanism of immune tolerance.