| ObjectiveTo investigate the frequnecies and malignant biological characteristics of T cell immunoglobulin and mucin3(TIM3) positive hematopoietic stem cells in myelodysplastic syndrome, and further explore the relationship between TIM3positive hematopoietic stem cells and myeloid-derived suppressor cells(MDSC) in bone marrow, IFN-γ+CD4+T cells, IFN-γ+CD8+T cells in peripheral blood.MethodsForty-nine untreated patients with MDS, twenty-two untreated patients with AML, as well as twenty-four normal controls were enrolled in the research. First Section The expression of TIM3on hematopoietic stem cells in bone marrow derived from patients with MDS, AML and normal controls were accessed by FACS. And then relationship analysis was done between TIM3+stem cells and clinical parameters in MDS patients. Second Section The expression of differentiated/proliferative molecule(CDllb/CD71), hematopoietic growth factor receptors(TpoR, EpoR, G-CSFR), transcription factors(GATA-1, GATA-2), and apoptosis molecule(Annexin V) on TIM3+/TIM3-stem cells in MDS patients and TIM3-stem cells in normal control were measured by FACS. Third Section We detected the frequencies of MDSC in bone marrow derived from MDS patients and normal control, and analyzed the relationship between TIM3+stem cells and MDSC in MDS patients. Fourth Section We detected the frequencies of IFN-γ+CD4+T cells and IFN-γ+CD8+T cells in peripheral blood derived from MDS patients and sex/age-matched control, and analyzed the relationship between TIM3+stem cells and IFN-γ+CD4+T cells, IFN-γ+CD8+T cells in MDS patients.ResultsFirst Section The median expression of TIM3on CD34+CD38-Lin-cells in MDS was significantly higher than that in controls(37.81%vs0.63%, P<0.001), and was close to that in AML(37.81%vs33.15%, P=0.527). The median MFI of TIM3+CD34+CD38-Lin-cells in MDS was significantly higher than that in controls(51.29vs4.69, P<0.001), and was close to that in AML(51.29vs68.63, P=0.455). TIM3+stem cells were negative related with the level of hemoglobulin(r=-0.378, P=0.009), the neutrophil counts(r=-0.470, P=0.001), and were positive related with the proportion of blast in bone marrow smear(r=0.364, P=0.014). The worse karyotype analysis showed, the higher TIM3+CD34+CD38-Lin-cells the MDS patients had (good:33.69±24.73%, intermediated:40.07±21.96%, poor:61.69±23.53%, F=4.575, P=0.016). The more cytopenias involving hematopoietic lineages, the higher TIM3+stem cells (F=5.912, P=0.005). The higher WPSS the patients got, the higher TIM3+CD34+CD38-Lin-cells the MDS patients had (F=4.176, P=0.002).Second Section There was no difference of molecules expression on TIM3-stem cells in MDS and control, thus it is reasonable to consider TIM3-stem cells in MDS as relative normal hematopoietic stem cells. Compared to TIM3-stem cells in MDS, TIM3+stem cells expressed lower CD11b (17.38±12.56%vs26.76±19.33%, P<0.001), lower hematopoietic factor receptors(TpoR:17.19±21.15%vs.26.91±26.88%, P<0.001; EpoR:31.88±19.51%vs.41.68±25.99%, P=0.009; G-CSFR:38.99±24.51%vs.47.30±24.15%, P=0.005), higher CD71(48.03±22.57%vs.30.81±23.87%, P<0.001) and higher GATA-2(64.04±22.90%vs.47.20±25.48%, P<0.001).Third Section The frequencies of MDSC in bone marrow from MDS patients were significant higher than that in controls (1.79±0.56%vs0.34±0.24%, P=0.014). The mean MFI of MDSC in bone marrow from MDS patients were significant higher than that in controls (47.90±37.37vs8.25±2.17, P<0.001). TIM3+stem cells were positively related with MDSC(r=0.556, P<0.001).Fourth Section The frequencies of IFN-γ+CD4+T in peripheral blood from MDS patients were significant lower than that in sex/age-matched controls (8.93±6.53%vs23.87±8.83%,t=-5.508, P<0.001). TIM3±stem cells were negatively related with IFN-γ+CD4+T cells (r=±0.579, P=0.009). The frequencies of IFN-γ+CD8+T in peripheral blood from MDS patients were significant lower than that in sex/age-matched controls (18.28±13.74%vs32.98±9.14%, t=-3.353, P=0.002). TIM3+stem cells were negatively related with IFN-γ+CD8+T cells (r=-0.590, P=0.008). Conclusions(1) TIM3+ hematopoietic stem cells in MDS patients were higher than those in control, and were close to AML. Increased TIM3+ stem cells were closely related with disease progression and poor prognosis of MDS patients.(2) TIM3- stem cells in MDS were considered as relatively normal hematopoietic stem cells, and TIM3+ stem cells in MDS displayed aberrant differentiation, overproliferation and decreased apoptosis compared with TIM3-stem cells in MDS.(3) The higher TIM3+ stem cells MDS patients had, the more MDSC they had. It hinted that TIM3+ stem cells were closely related with the increased MDSC.(4) The higher TIM3+ stem cells MDS patients had, the lower IFN-γ+CD4+T cells and IFN-γ+CD8+T cells they had. It hinted that TIM3+ stem cells were closely related with CD4+T and CD8+T cells dysfunction.(5) Increased TIM3+ stem cells in MDS patients may be the malignant clone cells that contribute to suppressing anti-tumor immunity and driving MDS into AML. |
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