The Expression Of Glucocorticoid-induced Tumor Necrosis Factor Receptor Of The Regulatory T Cells In The Patients With Systemic Lupus Erythematosus

Objective To investigate the expression of glucocorticoid-induced tumor necrosis factor receptor (GITR) of regulatory T cells (Tregs) in peripheral blood of the patients with systemic lupus erythematosus (SLE) in order to reveal that it plays the pathogenesis role in the SLE.Methods 32 patients (30 female and 2 male,, mean age 32.22±14.02 years, range from 15 to 57 years; the duration was 48.92±70.17 month) with a diagnosis of SLE according to the American College of Rheumatology criteria were included in the study. All SLE patients were referred to the Department of Rheumatology and Immunology, Anhui Provincial Hospital.15 normal volunteer (11 women and 4 men, mean age 28.67±4.40 years, range 25～38 years) without history of autoimmune diseases were also included in this study. All subjects received informed consent in this study. Group of patients: (1) The SLE patients were divided into active group (SLEDAI≥10) and inactive group (SLEDAI<10) according to the SLE disease activity index (SLEDAI). Active group included 21 patients (20 female and 1 male,, mean age 30.38±12.82 years, range 15～57 years; the duration was 1～288 month with the mean 53.19±79.97 month); Inactive group included 11 patients(10 female and 1 male, mean age 35.73±16.1 years, range 15～56 years; the duration was 0～144 month with the mean 40.75±48.60 month). (2) We also classified the patients into two groups according to the application of prednisone dose, the Maintenance group(prednisone dose≤10mg/d; SLEDAI 2～17, mean score 9.75±4.26) and Therapeutic dose group(prednisone dose>10mg/d;SLEDAI 8～22, mean score 12.69±4.99).The peripheral blood mononuclear cell (PBMC) were purified on Ficoll density gradient. PBMC layer was collected, and averagely divided into 6 tubes. the first one was set as blank. Anti-GITR-PE-IgG (5μL), anti-CD4-FITC(5μL), anti-GITR-PE(5μL) and anti-CD25-CY5 (5μL) were added into other four tubes, respectively. Anti-CD25-CY5(5μL),anti-CD4-FITC(5μL) and anti-GITR-PE(5μL) were added into the sixth tube.After incubatting the samples for 30 min at 4°C with avoidance of light. The cells were eluted with PBS solution (2 mL) twice. and were ready to be analyzed by flow cytometry. All the data were collected by FACSCalibur flow cytometer (FACSealibur system ,BD). The correlation of levels of GITR in these subsets with the clinic and laboratory parameters of SLE were analyzed.Result GITR-positive rates of was significantly higher in patients with active SLE than that in patients with inactive SLE .The GITR-positive rates of patients with inactive SLE was significantly higher than that in normal control group. The expression levels of GITR on CD4⁺CD25^highT was significantly higher than CD4⁺CD25⁺T and CD4⁺CD25^-T cell subset;The expression levels of GITR on CD4⁺CD25⁺T was significantly higher than CD4⁺CD25-T cell subset.(P<0.01). GITR expression in patients treated with corticosteroids also showed an increasing trend with dosage increasing. In the therapeutic dose group(prednisone dose>10mg/d), GITR expressions on the three T cell subsets were higher than that in the maintenance group(prednisone dose≤10mg/d) . But no significant difference was found between treatment groups and maintenance group.The expression levels of GITR on CD4⁺CD25^highT cells and CD4⁺CD25⁺T cells, were significantly positively correlated with the disease active index in SLE (SLEDAI) (r = 0.55, p<0.01; r=0.51, p<0.01). The expression levels of GITR of CD4⁺CD25^highT cells and CD4⁺CD25⁺T cells were correlated negatively with the hemoglobin (r=-0.40,p<0.05;r=-0.53,p<0.01).Conclusion The expression level of GITR on CD4⁺CD25highT cells was significantly increased in the active SLE group and had strong correlation with the SLEDAI. CD4⁺CD25highT cells express high level of GITR. The results suggest that GITR expression may associate to Tregs function, and play a role in the pathogenesis of SLE.