Myelodysplastic syndrome (MDS) comprises a heterogeneous group of malignant disorders.The diagnosis of MDS has always been the focus of attention of hematologists all over the world.From the FAB classification to 2008 WHO classification,the diagnosis of MDS has changed from completely morphological diagnosis to multi-parameter diagnosis.Nowadays,the diagnosis of MDS should involve multiple parameters concerning morphology,histochemistry,cytogenetics and immunology.

Objectives To detect the abnormalities of CD34+ cells differentiation and bone marrow cell cycle in myelodysplastic syndrome (MDS). Methods Fifty newly diagnosed MDS ( 17 in low risk and 33 in high risk), 8 acute myeloid leukemia preceded by MDS (MDS-AML) and 25 normal controls were enrolled into this study. Their CD34+ CD38+, CD34+CD38- bone marrow cells and bone marrow cell cycle were measured with flow cytometry. Results The mean percentages of CD34+ cells in bone marrow karyocyte of high risk [ (2.29 ±2.17)% ] and MDS-AML groups [ ( 18.69 ± 17.47)% ] were significantly higher than that of control group [ ( 0.36 ± 0.49 )%, P ＜ 0.05 ]. The mean percentages of CD34+CD38+ cells were significantly lower in low risk, high risk and MDS-AML groups [ ( 86.09 ± 7.79 )%, ( 81.68 ± 11.82)% and (82.88 ±2.60)%, respectively] than that in control group [ (92.21 ±3.85)%, P＜0.05], thus the percentages of CD34+CD38- cells were significantly higher in either MDS (low risk and high risk) or MDS-AML groups [ (13.91 ±7.79)%, (18.32 ±11.82)% or (17.13 ±2.60)%, respectively] than that in control group [ (7.79 ± 3.85 )%, P ＜ 0.05 ]. The percentages of CD+34 CD-38 cells of MDS cases correlated directly with their International Prognostic Scoring System (IPSS) (r =0.493, P =0.001 ) and WHO Adapted Prognostic Scoring System (WPSS) ( r = 0.586, P = 0.000 ) scores. The percentages of bone marrow mononuclea cells (BMMNCs) in G0/G1 phase of in low risk, high risk and MDS-AML groups [ (94.52 ±4.32)%, (96.07 ± 3.88 )% and (94.65 ± 4.55 )%, respectively ] were significantly higher than that in control group[ (88.94 ±7.30)%, P ＜0.01 ], thus the percentages of BMMNCs in S and G2/M phase were significantly lower in either MDS (low risk and high risk) or MDS-AML groups than that in control group (P＜0.05). MDS patients with low percentages of CD34+CD38- cells presented higher therapeutic efficacy than those with high percentages of CD34+CD38- cells, while without significant differences ( P ＞ 0.05 ) .Conclusions There are abnormalities of differentiation of CD34+ bone marrow cells and high proportion of G0/G1 cells which indicates a G1 phase arrest in MDS that might be involved in the pathogenesis of MDS. So the examination of CD34+ bone marrow cells and cell cycle might be helpful for MDS diagnosis and assessment of prognosis and therapeutic effects.

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 CD3+ 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 cells 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 ＜0.05 ].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.