Cell Cycle Distributions And Cell Proliferation-related Protein Expression In Myelodysplastic Syndromes, Aplastic Anemia, And Acute Leukemia

OBJECTIVE To explore the cell cycle distributions and the expressions of CD34 and Ki67, the cell proliferation-related protein in bone marrow mononuclear cells among myelodysplastic syndromes, aplastic anemia, and acute leukemia patients.METHODS Bone marrow aspirates were collected from 68 patients between June 2009 and June 2010 from the Department of Hematology, Provincial Hospital affiliated to Shandong University. The 68 cases consist of 30 MDS, including 18 refractory anemia and 12 refractory anemia with excess blasts,22 AA, including 7 severe aplastic anemia and 15 none severe aplastic anemia, and 18 AL, including 12 acute myeloid leukemia and 4 acute lymphoblastic leukemia.18 healthy individuals (non-hematologic patients) were used as normal control. Take 2 ml bone marrow from the patients. Propidium iodide and immunofluorescent double staining through flow cytometry were utilized to explore cell cycle distributions and the expression of CD34 and Ki67, the cell proliferation-related protein in bone marrow mononuclear cells.RESULTS1. Compared with the control group, the percentages of G0/G1 phase of cell cycle, haemopoietic stem/progenitor cells CD34+ cells, Ki67+ cells, CD34+Ki67+ cells, Ki67+ cells in CD34+ cells, and CD34+ cells in Ki67+ cells of BMMNC were all significantly increased in the MDS and AL group (P<0.01), whereas the percentages of S and S+G2/M phases of cell cycle were both significantly decreased (P<0.01), the proportion of G2/M phase of cell cycle was lower in the AL group compared to the control group (P<0.01). 2. As RA progressed to RAEB, the ratios of G0/G1 phase, CD34+ cells, Ki67+ cells, CD34+Ki67+ cells, Ki67+ cells in CD34+ cells, and CD34+ cells in Ki67+ cells were all significantly higher (P<0.05), but the ratios of S and S+G2/M phases were both lower (P<0.05); The proportions of G0/G1 phase, CD34+ cells, Ki67+cells, CD34+Ki67+ cells, Ki67+ cells in CD34+ cells, and CD34+ cells in Ki67+ cells were all significantly higher (P<0.01), while, the proportions of S and S+G2/M phases were both lower (P<0.01) in AL group compared to RAEB group.3. There were no significantly differences on cell cycle between AA group and the control group (P>0.05). The percentages of Ki67+ cells in CD34+ cells was significantly lower (P<0.05), as well as the percentages of CD34+ cells, CD34+Ki67+ cells, and CD34+ cells in Ki67+ cells of BMMNC were all significantly lower in the AA group than those in the control group (P<0.01).4. The percentages of G0/G1 phase, CD34+, Ki67+, CD34+Ki67+, Ki67+ cells in CD34+, and CD34+ cells in Ki67+ cells were all significantly increased (P<0.01), although the proportions of S and S+G2/M phases were both significantly decreased in the RA group than the AA group (P<0.01).CONCLUSIONS1. Most of the cells are kept at the G1 phase as well as the high proliferation of the haemopoietic stem/progenitor cells in MDS patients that can explain the dysdifferentiation and dysmaturity, which is the impaired peripheral blood cell production (cytopenias) as well as most commonly a hypercellular, dysplastic-appearing bone marrow. This greatly proves that the disorder of MDS might occur when the malignant damage of the haemopoietic stem/progenitor cells occurs.2. There are higher percentages of G1 phase as well as the high proliferations of the CD34+ cells in both MDS and AL patients. In our study, the ratios of G0/G1 phase, CD34+, Ki67+, and Ki67+ cells in CD34+cells were all significantly higher as RAEB progressed to AL as well as RA progressed to RAEB. This indicates that the disorder of MDS evolves the different stages and may eventually have the transformation to acute leukemia because of the expansion of malignant clonal cells from the haemopoietic stem/progenitor cells or because of more and more seriously qualitative defections in cells. Both of the two disorders may have the similar pathogenesis and may be the different stage of a common disease according to the theory of cell cycle and cell proliferation.3. There was no significant difference on the cell cycle between patients with AA and normal controls. It proves that AA is an illness without the malignant clonal mutation of haemopoietic stem/progenitor cells. We also found that besides the haemopoietic stem/progenitor cells were lower, the expressions of proliferations of BMMNC were all significantly lower in the AA group. It is different from patients with MDS and AL.4. The disturbance of cell cycle and the expression of cell proliferation were all different in patients with RA from AA, which can be used for the diagnosis and differential diagnosis of them. It is most different on the ratio of CD34+Ki67+ cells that may be 100% accuracy for the diagnosis and differential diagnosis of RA and AA.