Deficient Regulatory T Cells In The Peripheral Blood Of Patients With Systemic Lupus Erythematosus

To investigate roles of regulatory T cells in the pathogenesis of systemic lupus erythematosus (SLE),the peripheral blood mononuclear cells (PBMCs) from SLE patients were studied to observe the expression of CTLA-4in CD4+Treg and CD8+Treg which was closely related to the inhibitory function of CD4+Treg and CD8+Treg cells, The expression of CTLA-4and its correlation with disease activity as well as kidney damage were analyzed in the regulatory cell subsets CD4+CD25+.CD8+CD25+and CD8+CD28,in order to find a role of CTLA-4expression in SLE pathological process; Meanwhile,we also observed the ability of CD4+CD25’T to be induced into CD4+CD25+Foxp3+Treg in SLE patients to further explore the causes of regulatory T cells abnormality in SLE.Methods:(1) Extracted PBMCs(peripheral blood mononuclear cell) from SLE patients and healthy donors, cultured for48hours after anti-CD3and anti-CD28stimulating, collect the supernatant for ELISA assay of free CTLA-4level, Flow cytometer (FCM) was used to get the percentages of CTLA-4+/CD4+CD25+CD25+CTLA-4+/CD4+、CTLA-4+/CD8+CD25+、CD25+CTLA-4+/CD8+、CD25-CTLA-4+/CD8+CD28-CTLA-4+/CD8+、CTLA-4+/CD8+CD28-, Correlation analysis was made between the percentages and SLEDAI, kidney damage (2) Isolation of CD4+CD25T cells from SLE patients and healthy donors, The ability of CD4+CD25-T cell to be induced into CD4+CD25+Foxp3+Treg was examined in the stimulated culture system including anti-CD3、anti-CD28、TGF-βand IL-2. Correlation analysis was made between the percentages of induced regulatory T cells and SLEDAI.(3) Extracted PBMCs from SLE patients and healthy donors, FCS was used to get the percentages of CD4+CD25-TGF-βR I+、CD4+CD25-TGF-βRⅡCD4+CD25-CD122+and CD4+CD25-CD132+,analyzed the percentages and their correlation with SLE activity.Results:(1) The CTLA-4expression were significantly higer in SLE than controls,they were positively correlated with disease activity;but the inducible expression of CTLA-4in SLE were deficient. PBMCs from SLE patients exhibited lower ratio of CD25+CTLA-4+/CD4+、CTLA-4+/CD4+CD25+T、CD25+CTLA-4+/CD8+T, CTLA-4+/CD8+CD25+T、CD28-CTLA-4+/CD8+T、CTLA-4+/CD8+CD28-T than controls after stimulated with anti-CD3and anti-CD28, indicated defective CTLA-4expression in SLE patients T cells, the radios had no significantly correlation with disease activity; ratios of CD28-CTLA-4+/CD8+T CTLA-4+/CD8+CD28-T were lower in active SLE patients with kidney damage than active SLE patients without kidney damage, while supernatant CTLA-4level of SLE patients was lower than controls after stimulated with anti-CD3and anti-CD28.(2) We had established CD4+CD25+Foxp3+T cell induced culture system with anti-CD3, anti-CD28, TGF-β and IL-2. CD4+CD25-T cells from active SLE patients could hardly be induced into CD4+CD25+Foxp3+Treg cells with anti-CD3, anti-CD28, TGF-β and IL-2. While with lower inducible percentage than controls, CD4+CD25T cells from inactive patients could be induced into CD4+CD25+Foxp3+Treg. The percentage of induced CD4+CD25+T and CD4+CD25+Foxp3+T cells were negatively correlation to disease activity.(3) CD132expression on CD4+CD25-T were lower in SLE patients than controls, and the radios were negatively correlation with disease activity. The ratio of CD25" CD132+/CD4+、CD132+/CD4+CD25-was reduced in SLE patients,which were negatively correlation with SLEDAI. The expression level of TGF-β receptor I was slightly higher than controls; CD4+CD25-T cells from SLE patients and controls had no expression of CD122and TGF-P receptor Ⅱ.Conclusions:Evidence for regulatory T cell deficient in SLE patients.(1) The ability of CD4+CD25" T into CD4+CD25+Foxp3+iTreg was significantly reduced,which had negatively correlation with disease activity.(2) The constructive expression of IL-2R yc on CD4fCD25-T in SLE patients T cells was decreased, and the levels were negatively correlation with disease activity.(3) The expression of induced CTLA-4in SLE patients T cells was significantly reduced. The deficient in SLE patients’T cells mentioned above may be involved in SLE pathological process.