Changes And Clinical Significance Of CD8~+ Regulatory T Cells In The Peripheral Blood Of Patients With Ankylosing Spondylitis

Objective The aim of our study was to explore the relationship between circulating Treg cells and ankylosing spondylitis(AS)disease by comparing the percentage of CD8~+CD122~+T,CD4~+CD25~+T and CD8+CD28-T expression level in peripheral blood between patients with AS and healthy controls and analyzing the correlation between Treg cells expression level and the clinical features or related cytokines,then to find the role of the Treg cells in the pathogenesis and prognosis of AS.Methods With the method of case-control design,40 patients with AS from the First Affiliated Hospital of Anhui Medical University and 40 age-and sex-matched healthy controls(HC)were recruited during the period of December 2015 to August2016.The patients with AS were clarified as short and long duration of patients group,depending on whether the disease duration was more than 12 months.At the same time,the patients were collected and analyzed according to the use of non steroidal anti-inflammatory drugs(Non-steroidal anti-Inflammatory drugs,NSAIDs)and the use of biological agents.5ml venous blood of cases and controls was collected,and then serum and peripheral blood mononuclear cells were isolated.By adopting the questionnaires,epidemiological information of AS patients was obtained.The percentage of circulating CD4~+CD25~+T,CD8~+CD122~+T,CD8+CD28-T and CD4+CD28-T cells was detected by flow cytometry among AS patients and HC.Plasma IL-2,IL-10,IL-15,TGF-β1 and TNF-ɑ levels were quantified by enzyme-linked immunosorbent assay.The expression difference of each factor between AS group and HC was compared and the correlations among those factors were analyzed.Based on the data distribution,continuity and normalized distribution data were described with mean and standard deviation(SD),while the non-normalized and continuity data were presented as median and interquartile range(IQR).The t test was used to compare between groups,correlation analysis with Spearman rank and Pearson correlation were performed.SPSS 16.0 and Graph Pad Prism 5.0 software were adopted.In the present study,the P value with two-tailed was set as 0.05,while the value less than 0.05 was considered to be statistically significant.Results The percentage of circulating CD4~+CD25~+T and CD8~+CD122~+T cells were significantly increased in AS patients compared with HC(t= 2.066,P=0.042;Z=-4.917,P=0.001),and the circulating CD4~+CD25~+T cells of AS patients with long disease duration was especially higher than that of healthy controls.Plasma IL-2,IL-10,IL-15,TGF-β1 and TNF-ɑ level between case and control group was compared but no statistically significant difference was found.Besides,no significant association between the percentage of T cells and related cytokines was detected.What’s more,the percentage of circulating CD4~+CD25~+T,CD8~+CD122~+T,CD8+CD28-T and CD4+CD28-T cells were not different significantly in the two groups of patients with AS whether they were treated with biologics agent or not.Besides,the percentage of circulating CD4~+CD25~+T,CD8~+CD122~+T and CD4+CD28-T cells were not different significantly in the two groups of patients with AS patients whether they were treated with NSAIDs or not.However,the percentage of circulating CD8+CD28-T were significantly higher when patients were not treated with NSAIDs(t=2.765,P=0.009).The percentage of circulating CD8+CD28-T did not detect significant difference between AS patients and Healthy controls,while the cells count of the CD8+CD28-T cell was significantly associated with the level of inflammatory level(CRP)and the score of BASFI in AS patients,positively(rs=0.383,P=0.041;rs=0.321,P=0.043,respectively).In addition,the percentage of circulating CD8~+CD122~+T cells was positively correlated with disease duration(rs=0.359,P=0.032)and positively associated with the percentage of circulating CD8~+CD122~+T cells(rs=0.428,P=0.026)in the patients with long disease duration.Conclusion The CD4~+CD25~+T,CD8~+CD122~+T and CD8+CD28-T cells in the peripheral blood of AS patients may be involved in the development of AS,and CD8+Treg cells of CD8~+CD122~+T and CD8+CD28-T cells may coordinate regulate inflammation and immune dysregulation in patients with AS,which may play an important role in the pathogenesis and prognosis of AS.