Study On The Effect Of Decitabine On The Proportions Of Tregs In Peripheral Blood Of Patients With MDS/AML

Objective:Myelodysplastic syndrome(MDS)and acute myeloid leukemia(AML)are both myeloid malignancies,which are difficult to cure and are more likely to relapse.Decitabine(DAC)is a kind of hypomethylating agents(HAMs),which is essentially DNA methyltransferase inhibitors(DNMTs).It has been approved by the FDA for MDS and AML treatment.There are a variety of immune cell disorders in patients with MDS and AML,which may lead to tumor immune escape and weakening of anti-tumor immune response,so that tumor can continue to occur and develop.Studies have shown that DAC can change the number and function of various immune cells to reactivate the dormant anti-tumor immune response.Regulatory T cells(Tregs)play a very important role in the occurrence of autoimmune diseases and tumors,and can control and regulate the body’s immun system,thereby effectively resisting the function of overreaction.Current studies have shown that DAC may affect the number and function of Tregs.In this study,the relative content of Tregs in newly diagnosed MDS and AML patients and after one circle treatment(DAC treatment group,non-DAC treatment group)were compared to explore the mechanism of immune cells in MDS and AML patients and the effect of DAC on tumor immunity in MDS and AML patients.Methods:The specimens of this study were collected from 120 patients in the Department of Hematology,the First Affiliated Hospital of Kunming Medical University,Yunnan Province between October 2018 and February 2020,including 26 patients with MDS,74 patients with AML,and 20 patients in the control group.(Patients with IDA or MA ruled out of malignancies).Collect 3-4ml of peripheral blood from patients,and detect the relative content of Tregs cells by flow cytometry within 36 hours.Results:1.In MDS patients:1.1 The relative content of Tregs in the newly diagnosed group has a tendency to increase compared with the control group,but there is no significant statistical difference(P=0.247).1.2 The relative content of Tregs in MDS patients after DAC treatment had a decreasing trend compared with the newly diagnosed group,but no significant statistical difference(P=0.443).1.3 The relative content of Tregs between the DAC treatment group and the control group was not statistically significant(P=0.787).1.4 There was no significant difference in the relative content of Tregs among MDS patients with different risks(P>0.5).2.In AML patients:2.1 The relative content of Tregs in the newly diagnosed group was higher than control group(P=0.001).2.2 After DAC treatment,the relative content of Tregs showed a downward trend compared with the newly diagnosed group,but there was no significant statistical difference(P=0.268).2.3 There was no significant difference in the relative content of Tregs between the DAC treatment group and the control group(P=0.075),and the relative content of Tregs in the non-DAC treatment group was significantly higher than control group(P=0.000).2.4 The relative content of Tregs in the DAC treatment group was significantly lower than that in the non-DAC treatment group(P=0.020).2.5 There was no significant difference in the relative content of Tregs among AML patients with different prognosis types(P>0.5).2.6 The relative content of Tregs in the DAC treatment remission group was lower than newly diagnosed group(P=0.017),and there was no significant difference between the non-DAC treatment remission group and the newly diagnosed group(P=0.849).Conclusions:1.Tregs may be participate in the mechanism of tumor immune escape in AML patients.2.In AML patients,compared with traditional chemotherapy,DAC may reduce the content of Tregs in the body,weaken the immune escape function of tumors,and enhance the body’s immune function against tumors to monitor,recognize and kill tumor cells,thereby promoting immune monitoring,recognition and killing of tumor cells Remission of the patient’s disease.3.Whether DAC has a similar immunomodulatory effect in MDS patients remains to be studied.4.In AML patients,conventional chemotherapy may not be effective for Tregs.5.Whether the relative content of Tregs after treatment is related to the poor prognosis of the disease needs further research.