Significance Of CD200 And CD4⁺CD25⁺CD127^low Treg In Ankylosing Spondylitis

BackgroundAnkylosing spondylitis(AS)is a chronic immune inflammatory disease that mainly invades the spine,sacroiliac joint,ankle joint and peripheral joint.Its occurrence is related to many factors.The specific pathogenesis is not yet clear.Studies at home and abroad have shown that the number of T lymphocyte subsets in AS patients can be imbalanced in the course of disease progression.In recent years,the relationship between regulatory T cells(Treg)and autoimmune diseases has become a research hotspot.CD200,a newly discovered glycoprotein with immunosuppressive function,has become an independent predictor of systemic lupus erythematosus,rheumatoid arthritis and other autoimmune diseases.However,the significance of CD200 in AS remains unclear.ObjectiveIn this study,Flow cytometry(FCM)and Enzyme-linked immunosorbent assay(ELISA)were used to detect the expression of CD200 in peripheral blood,the percentage of Treg and the concentration of CD200,interleukin-6(IL-6)and serum amyloid A(SAA)in AS patients.The correlation between CD200 and Treg,IL-6 and SAA was analyzed,and the diagnosis of AS diseases and the evaluation of immune function of AS patients were discussed.The value of this method not only provides help for clinical diagnosis of AS,but also provides new ideas for the treatment of AS.Methods1.Objectives:According to the diagnostic criteria of"Guidelines for the Diagnosis and Treatment of Ankylosing Spondylitis"formulated by the Rheumatology Society of Chinese Medical Association,74 patients with AS admitted to The First Affiliated Hospital of Xinxiang Medical University from February 2018 to February 2019 were selected and grouped according to the ASDAS score:more than or equal to 1.3 were divided into AS active group,50 cases;less than 1.3 into AS stable group,24 cases.During the same period,50 healthy people with normal physical examination and excluding autoimmune diseases were selected as control group.2.Detection methods:Blood samples of all subjects were collected.The peripheral blood lymphocyte subsets,CD200 ratio,Treg content and HLA-B27 were detected by FCM.The concentration of CD200 in serum was detected by ELISA.The content of IL-6in serum was detected by up-repeater light method.The content of SAA in serum was detected by latex immunoturbidimetry.3.Statistical processing:SPSS20.0 software was used.When all measurement indicators conform to normal distribution,they are measured by mean±standard deviation(x±s).T-test was used to compare the mean of two groups,Chi-square test was used for counting data,Pearson linear correlation analysis was used for correlation analysis,and ROC curve was used to analyze the diagnostic efficacy of each index,z-test is used to compare AUC between indicators.The difference was statistically significant(P<0.05).Results1.Comparison of lymphocyte subsets:Compared with the control group,the percentage of CD3~+CD4~+T cells and CD19~+B cells increased in the active group(P<0.05),while the percentage of CD3~+CD8~+T cells and CD56~+NK cells decreased in the active group(P<0.05).The percentage of CD3~+T cells in the active group and the percentage of lymphocyte subsets in the stable group had no statistical significance.2.Comparison of Tregs:Compared with the control group,Treg percentages in the active group decreased(P<0.001),while Tregs in the stable group had no statistical significance.3.The expression rate of CD200 in lymphocyte subsets:Compared with the control group,the expression rate of CD200 on CD3~+,CD4~+,CD8~+T cells in the active group was significantly lower(P<0.001),while the expression rate of CD200 on CD19~+B cells had no statistical significance;the expression rate of CD200 on CD3~+,CD4~+T cells in the stable group was lower(P<0.01),while the expression rate of CD200 on CD8~+T cells and CD19~+B cells had no statistical significance.4.Comparison of serum levels of CD200,IL-6 and SAA:Compared with control group,serum levels of CD200 in active group decreased significantly(P<0.01),IL-6 and SAA increased significantly(P<0.01);serum levels of CD200 in stable group decreased(P<0.05),while serum levels of IL-6 increased(P<0.05),SAA had no statistical significance.5.The correlation analysis of CD200 expression rate in CD3~+T cells with Treg IL-6and SAA of active group:CD200 expression rate in CD3~+T cells of active group was positively correlated with Treg(r=0.345,P<0.05),negatively correlated with IL-6(r=-0.352,P<0.05),not correlated with SAA;Treg expression rate in active group was negatively correlated with IL-6(r=-0.592,P<0.01),not correlated with SAA.6.Analysis of diagnostic efficacy of CD200 and Treg,IL-6 and SAA:CD200 is superior to Treg and SAA in predicting inflammatory activity of AS(P<0.001),but similar to IL-6.ConclusionsCD200 and Treg may participate in the occurrence and development of AS,and are related to disease activity and immune function.CD200 has high sensitivity and specificity as a predictor of immune function and disease activity in AS patients.