The Change And Its Clinical Significance Of CD8~+T Cell Subset In AA, MDS And AML Patients

OBJECTIVE To detect the balance and the change of activity of cytotoxic T cell subsets in aplastic anemia(AA) patients, myelodysplastic syndrome (MDS)patients and acute myeloid leukemia (AML)patients,and to explore the cellular immune mechanism for abnormal hematopoiesis of the three diseases, and to provide experiental basis for the choice of clinical treatment.METHODS During the time between july2011and july2012,collected the Peripheral Blood Mononuclear Cell(PBMC) from77patients from the Department of Hematology, Provincial Hospital affiliated to Shandong Uneiversity. The77cases consist of35MDS, including19refractory anemia and16refractory anemia with excess blasts,17AA and15AML patients.10healthy individuals (non-hematologic patients) were used as normal control. By FACS, the proportion of cytotoxic T cells and part of the T-cells subsets in peripheral blood were detected in order to evaluate the status of cellular immune.RESULTS1. Compared with the control group, the percentage of Tc1、Tc1/Tc2、 CD8+HLA-DR+、CD3+CD8+CD28+、CD8+CD45RO+were significantly higher (P<0.05, P<0.01) and the percentage of CD8+CD45RA+were lower in AA (P<0.01); There were no difference in the percentage of Tc2cells between AA and control groups.The percentage of CD8+CD45RO+were significantly higher (P<0.05) and the percentage of CD8+CD45RA+(P<0.05) were lower and other parameters were no difference in MDS; The percentage of Tc1、Tc1/Tc2、CD3+CD8+CD28+CD8+CD45RO+、CD3+HLA-DR+(P<0.05) were significantly higher and the percentage of CD8+CD45RA+were lower in MDS-RA(P<0.01), but there was no difference in the percentage of Tc2cells between MDS-RA and control groups(P>0.05).The percentage of CD8+CD45RO+were significantly higher (P<0.05) and the percentage of Tc1、 CD3+CD8+CD28+、CD8+HLA-DR were lower (P<0.05) and there was no difference in the percentage of Tcl/Tc2in MDS-RAEB,there was no significant changes but have a rising trend in the the percentage of Tc2and the percentage of CD8+CD45RA+were lower but the difference were not obvious between MDS-RAEB group and the control group.The percentage of Tc2were higher (P<0.05) and the percentage of Tc1、Tc1/Tc2、CD3+CD8+CD28+、 CD8+CD45RA+、CD8+CD45RO+、CD8+HLA-DR+were lower (P<0.01)in AML.2. Compared with the AA group, the percentage of Tc1/Tc2、CD3+CD8+CD28+CD8+CD45R0+were lower in MDS-RAEB(P<0.05,P<0.01). The were no difference in other parameters between MDS-RA and the AA group.3. Compared with the MDS-RA group, the percentage of Tc1, Tc1/Tc2、 CD3+CD8+CD28+、CD3+HLA-DR+were lower and the percentage of Tc2cells were higher(P<0.05,P<0.01) but the difference were not obvious in MDS-RAEB. The were no difference in other parameters between the MDS-RAEB and the MDS-RA group.4. Compared with the MDS-RAEB group, the percentage of Tc2cells was higher (P<0.05) and the percentage of other parameters were significantly lower in AML group than those of the MDS-RAEB group(P<0.05,P<0.01).CONCLUSIONS1. The number of CD8+CTL cells in patients with the AA group increase significantly,the Tc cells group polarize to Tel cells,the transformation from CD45RA+T to CD45RO+T increase,and the immune system is overactive,all of which confirm the fact that the Immunological pathogenesis in patients with AA is due to the hematopoietic failure caused by T-cell’s abnormal activation and proliferation.2.The immune status in AA and MDS-RA group are similar,compare the changes of T-cell subset in the two groups, the difference is not significant,which indicate that anti-tumor immunity play a major role and lead to the excessive apoptpsis then to the bone marrow failue.But the immune stataus is different in MDS-RA and MDS-RAEB.With the progression of the disease, malignant clone in vivo increases, the low immunity can not eliminate tumor cells effectively,which can cause the disease to progress rapidly and even to turn into acute myeloid leukemia.3.The results of AML group is similar with MDS-RAEB group, the body’s celluar immune function continue to decline and the number cells which have the function of anti-tumor decrease,all of these make the body’s immune function of this stage present further suppress.4.The cellular immune status in AA,the different stages of MDS and AML is differernt.In AA and the early stage of MDS,the balance of Tcl/Tc2shifts to Tc1, and the activation of T-cell subsets were enhanced.In the late stage of MDS and AML, the balance of Tcl/Tc2shifts to Tc2,the activation of T-cell subsets were decreased.The former may closely related to bone marrow failure while the latter may be one of the important mechanisms of malignant clone and immune eacape.