Study Of Mixed Connective Tissue Disease In Patients With Peripheral Blood CD4~+T Lymphocyte Subsets Analysis And Effect Of Short-term And Low Dose IL-2 Treatment On It

Objective:1.To explore the status of CD4~+T lymphocyte subsets in peripheral blood of patients with MCTD;2.To observe the effect of low dose and short-term interleukin-2(IL-2)treatment on the balance of Th17 and Treg cells in patients with MCTD.Methods:58 MCTD patients and 33 healthy people were collected.All patients met the applied criteria established by Sharp for the diagnosis of MCTD.Patients with severe infection,tumor and other autoimmune diseases(such as RA,SLE,SSc)were excluded.The study is divided into three parts.First,58 MCTD patients and 33 healthy people were taken as the case group and the healthy control group,and the peripheral blood CD4~+T lymphocyte subsets were detected in the two groups.Second,58 cases were divided into A group(n=26)and B group(n=32).26 cases in group A used low-dose glucocorticoids(GCS),non steroidal anti-inflammatory drugs(NSAIDs)and hydroxychloroquine.The 32 cases of B group for nearly 1 year using the same drug 0f A group,also used immunosuppressant cyclophosphamide(CYC),methotrexate(MTX),leflunomide(LEF)or mycophenolate mofetil(MMF).The peripheral blood CD4~+T lymphocyte subsets were compared in the two groups.Third,27 patients were selected in case group,including 13 cases of A group and 14 cases of B group,with a small dose ofIL-2(50WIU)treatment for 5 days.CD4~+T lymphocyte subsets in peripheral blood before and after treatment with IL-2 were detected.CD4~+T lymphocyte subsets in the peripheral blood were analyzed by flow cytometry,including the percentage and absolute count of Th1,Th2,Th17,Treg cells and the ratio 0f Th1/Th2,Th17/Treg.Results:1.The absolute count of Th1 and CD4~+CD25~+FOXP3~+Treg cells in peripheral blood of patients with MCTD was significantly lower than those in healthy controls(P=0.006,P=0.006),while the absolute count of CD4~+CD25~+Treg cells in peripheral blood of patients with MCTD was not significant difference than those in healthy controls(P=0.309).The percentage of Th1,Th2,Th17 and Treg,and the absolute count of Th2,Th17 cells in peripheral blood of the two groups were not statistically significant(P values>0.05).2.The absolute count of CD4~+CD25~+FOXP3~+Treg cells in the peripheral blood of group A and group B were lower than those in the healthy controls(P<0.05,P<0.01);while there was no significant difference in the absolute count of CD4~+CD25~+FOXP3~+Treg cells in the peripheral blood between group A and group B.3.The absolute count of CD4~+CD25~+FOXP3~+Treg cells in peripheral blood of patients with MCTD after treatment with IL-2 was significantly higher than those before treatment with IL-2(P<0.001),while the absolute count of Th2 and Th17 cells were Slightly higher than those before treatment with IL-2(P<0.05,P<0.01).Conclusion:1.The absolute count of CD4~+CD25~+FOXP3~+Treg cells in peripheral blood of patients with MCTD was significantly reduced,which may be one of the main mechanisms of immune imbalance in MCTD patients.2.The detection of CD4~+CD25~+FOXP3~+Treg cell counts in peripheral blood of patients with MCTD is better than the percentage and CD4~+CD25~+Treg cells.significantly reduced,which may be one of the main mechanisms of immune imbalance in MCTD patients.The decrease of the absolute count of CD4~+CD25~+FOXP3~+Treg cells in peripheral blood of patients with MCTD was not obvious associated with the use of immunosuppressive agents(CYC,MTX,LEF and MMF).3.Low dose and short-term IL-2 treatment may increase the absolute count of CD4~+CD25~+FOXP3~+Treg cells in the peripheral blood in patients with MCTD,so as to restore the immune balance in patients with MCTD.