The Quantity And Expression Characteristics Of Regulatory T Cells And Their Surface Factor PD1/PDL-1 In Peripheral Blood Of Patients With Autoimmune Thyroid Disease

Background:Autoimmune thyroid disease?AITD?is an organ-specific autoimmune disease characterized by intrauterine lymphocytic infiltration and thyroid autoantibody production caused by autoimmune dysfunction.Recent studies have shown that regulatory T cells?Treg?can participate in the pathogenesis of AITD by inhibiting peripheral reactive T cells and inhibiting autoimmune responses.Programmed cell death-1?PD-1?/programmed cell death ligand?PD-L?co-stimulatory pathway is a negative co-stimulatory pathway discovered in recent years,enhanced or blocked this pathway is associated with the immune process of autoimmune thyroid disease.PD1/PD-L1 was simultaneously expressed on Treg cells.This article discusses the role of regulatory T cells and PD1/PDL-1 signaling pathways in autoimmune thyroid disease.Objective:1.To study the ratio of CD4+CD127+T cells and the mean fluorescence intensity?MFI?of CD127 in peripheral blood of patients with autoimmune thyroid disease,and to discuss the correlation between autoimmune thyroid disease and activated T?CD4+CD127+?cells;2.To study the proportion of Treg(CD4+CD25+CD127^low)cells in peripheral blood of patients with autoimmune thyroid disease,and to discuss the correlation between autoimmune thyroid disease and the number of Treg cells;3.To study the proportion of PD-1+and PDL-1+Treg(CD4+CD25+CD127^low)cells in peripheral blood of patients with autoimmune thyroid disease,and to discuss the correlation between autoimmune thyroid disease and the number of PD-1+and PDL-1+Treg cells;Methods:We collected peripheral blood 2-3ml from the health control,the patients with Hashimoto's thyroiditis,the patients with Graves' disease in the second affiliated hospital of Dalin Medical University during May,2018 to December,2018.PBMC was isolated by Ficoll density gradient centrifugation,Flow cytometry?FCM?was performed immediately after cell surface staining.through Flow cytometry gates calculated sequentially the ratio of Peripheral blood lymphocyte population,CD127+,CD25+CD127^low cell in peripheral blood CD4+ T cells.Results:1.The percentage of peripheral blood CD4+CD127+ T cells in total lymphocytes and the mean fluorescence intensity of CD127 in CD4+CD127+ T cells?MFI?were not statistically different between the Hashimoto's thyroiditis group and the control group and Graves' disease group?P>0.05?;There was no significant difference between the patients with Graves disease and the control group?P>0.05?.2.The percentage of CD25+CD127^low T cells in CD4+ T cell in Hashimoto's thyroiditis group and control group were?2.94±0.61?vs?5.60±1.26?,?P<0.05?.The difference was statistically significant,indicating that The proportion of peripheral blood CD4+CD25+CD127^low T cells in Hashimoto's thyroiditis patients decrease compared with healthy controls;The patients with Graves disease and Hashimoto's thyroiditis group were?5.78±1.74?vs?2.94±0.61??P<0.05?,the difference was statistically significant;there was no significant difference compared with the control group?P>0.05?.3.The ratio of PD-1+Treg cells in peripheral blood Treg(CD4+CD25+CD127^low)cells was compared with the control group and Graves disease group?6.54±1.80?vs?1.22±0.70??P<0.05?.?6.54±1.80?vs?3.87±3.43??P<0.05?,the difference was statistically significant,indicating that the proportion of PD-1+ Treg cells in peripheral blood Treg cells of patients with Hashimoto's thyroiditis was higher than that of healthy controls and patients with Graves' disease.The Graves disease group compared with the control group?3.87±3.43?vs?6.54±1.80??P<0.05?,the difference was statistically significant,indicating that the proportion of PD-1+ Treg cells in peripheral blood Treg cells of patients with Graves disease was higher than that of healthy controls.4.The proportion of PD-L1+Treg cells in peripheral blood Treg cells was compared with the control group and Graves disease group?4.56±1.66?vs?0.97±0.37??P<0.05?,?4.56±1.66?vs.?2.01±1.66??P<0.05?,the difference was statistically significant,indicating that the proportion of PD-L1+Treg cells in peripheral blood Treg cells of patients with Hashimoto's thyroiditis was higher than that of healthy controls and patients with Graves' disease;The Graves disease group was compared with the control group?2.01±1.66?vs?0.97±0.37??P<0.05?.The difference was statistically significant,indicating that the proportion of PD-L1+Treg cells in peripheral blood Treg cells of patients with Graves disease was higher than that of healthy controls.Conclusion:The proportion of Treg cells in peripheral blood of patients with Hashimoto's thyroiditis was lower than that of healthy controls and patients with Graves disease,but the proportion of Treg cells in peripheral blood of patients with Graves disease was not significantly different from that of healthy controls,indicating that Treg cells have a significant role in Hashimoto's thyroid disease,but not in Graves' disease.The expression of PD-1 and PDL-1 on the surface of Treg cells in patients with Hashimoto's thyroiditis and Graves' disease was increased,but the expression in Graves' disease patients was not as high as that of Hashimoto.The change of PD-1/PDL-1 was inversely proportional to the change of Treg number,suggesting that PD-1/PDL-1 factor is associated with the change of Treg number and autoimmune thyroid disease.