The Distribution And Mechanism Of Regulatory B Cells In Acute Myeloid Leukemia

Background:Acute myelocytic leukemia?AML?is a clonal malignant hyperplasia disease of the hematopoietic system.The pathogenesis of AML is related to the environmental?physical and chemical factors?,cytotoxic drugs,viral infection and family genetic factors,etc.,which may lead to the disorder of AML autoimmune function and the formation of immune tolerance.In recent years,more and more attention has been paid to the immunotherapy and related research on malignant hematological diseases such as AML.Therefore,in-depth study on the immunological mechanism of the pathogenesis of AML may provide theoretical basis for the immunotherapy of AML in the future.At present,the immunological mechanism of AML is still unclear.It is generally believed that immune cells affecting tumor mainly include regulatory T cells,effector T cells and B cells.B cells have the ability to produce antibodies and activate T cells.Studies found that there is a group of B cells with role of negative regulation through the secretion of IL-10 and other cytokines.It can inhibit the immune response of effector T cells to tumors,so regulatory B cells?Breg cells?may participate in the immune regulation of tumors^[1,2].Regulatory T cells?Treg cells?,Th1 cells,Th17 cells,and the balance between them not only play an immune role in tumor^[3-5],but also play an important role in the immune regulation of AML^[6-8].However,the expression pattern and immunomodulatory mechanism of Breg cells in AML are still unclear.Therefore,To explore the expression pattern of Breg cells and the regulatory mechanism of Breg cells is contribute to revealing immunological theory of AML pathogenesis,which may provide theoretical basis for seeking new targets and strategies for AML immunotherapy.Objective:To analyze the expression patterns of Breg cells,Treg cells,Th1 cells,Th2cells and Th17 cells in AML patients by comparing the frequency of Breg cells,Treg cells,Th1 cells,Th2 cells and Th17 cells in peripheral blood/bone marrow of AML with the healthy controls.To analyze the expression patterns of cytokines secreted by Breg cells and T cells by comparing the levels of cytokines in peripheral blood of AML with the healthy controls.In order to verify the functions of Breg cells and explore the immunology pathogenesis of AML,we cocultured the B cells and CD4⁺CD25^-T cells.To explore the clinical significance of Breg cells by analyzing the relationship between Breg cell frequency and clinical data of AML patients.Methods:?1?analyze the expression patterns of Breg cells,Treg cells,Th1 cells,Th2cells and Th17 cells in patients with AML by detecting the frequency of Breg cells,Treg cells,Th1 cells,Th2 cells and Th17 cells in AML and healthy donors?HD?by flow cytometry;?2?analyze the expression patterns of cytokines secreted by Breg cells and T cells by detecting the concentration of IL-10,TGF-?1,IFN-?,IL-2,IL-4 and IL-17A;?3?Magnetic beads were used to separate B cells and CD4⁺CD25^-T cells for coculture in vitro.To illustrate the function of Breg cells and the immune regulation mechanism of AML by observing the effects of Breg cells on CD4⁺CD25^-Tcells.?4?reveal the clinical significance of Breg cells in AML by analyzing the clinical data of AML patients.Results:?1?The frequency of Breg cells and Treg cells in bone marrow/peripheral blood of AML patients were significantly increased compared to the healthy controls.However,the frequency of Th1,Th2 and Th17 cells showed no statistical changes.?2?The levels of IFN-?,IL-2,IL-4,IL-17A and TGF-?of AML patients were lower than the controls,but there was no significant differences in the levels of IL-10;?3?In the coculture system of B cells of AML patients and CD4⁺CD25^-T cells of healthy controls,the frequency of Treg cells was significantly increased,while the levels of IFN-?,IL-2,IL-4and IL-17A were significantly decreased.In the coculture system of B cells of healthy controls and CD4⁺CD25^-T cells of AML patients,no significant changes were observed in the frequency of Treg cells and the levels of IFN-?,IL-2,IL-4 and IL-17A;?4?Compared with AML patients with low WBC,the frequency of Breg cells were elevated in patients with high WBC.Compared with the low-risk group,the frequency of Breg cells were increased in patients with AML in the medium-risk group and high-risk group.The frequency of Breg cells in the group with good prognosis was significantly lower than that in the group with medium prognosis,poor prognosis and unknown prognosis.The overall survival rate of AML patients with high WBC and high Breg cells was significantly lower than that with low WBC and low Breg cells.The overall survival rate of patients with years over 60 at the same time with high Breg cells was significantly lower than that of patients with years under 60 at the same time with low Breg cells.Conclusion:The increased expression of Breg cells in AML patients can induce Treg cells and inhibit the function of Th1,Th2 and Th17 cells,which participate in the pathogenesis of AML.On the other hand,Breg cells can screen high-risk AML patients and provide theoretical basis for immunotherapy of AML in the future.