| Partl Expression of IL-17-producing T lymphocytes in peripheral blood of patients with systemic lupus erythematosus and their correlations with disease activityObjectiveSystemic lupus erythematosus(SLE)is a chronic autoimmune disease with unclear etiology and pathogenesis.SLE may be related to sex,hormone,heredity,infection,environment,immunity and other factors.Abnormal activation of T cells and B cells produce a variety of cytokines,autoantibodies and immune complex depositions,resulting in tissues and organs damaged.The clinical manifestations of SLE are varied,involving the skin,blood,heart,lung,kidney and other organs and systems.IL-17,a kind of cytokines derived from activated T cells,is involved in the occurrence or development of autoimmune diseases such as psoriasis,rheumatoid arthritis,etc.As a common autoimmune disease,SLE may be similar to psoriasis,rheumatoid arthritis and other diseases which means its pathogenesis is closely related to IL-17 and IL-17+γδ T cells.However,there were few studies on SLE and IL-17+γδ T cells.Most of studies only detected the level of IL-17 in peripheral blood of SLE patients by ELISA.Early studies suggested that IL-17 was produced by Th17 cells and CD3+CD4-CD8-T cells.Our previous study found that IL-17 was produced by Th17 cells.The level of IL-17 in PBMC of active lupus patients was significantly increased and correlated with systemic lupus erythematosus disease activity index(SLEDAI).Recent researches have found that γδ T cells also produce IL-17.The purpose of this study is to determine the type of T cells secreting IL-17 in peripheral blood of patients with SLE and the role of y8 T cells in the pathogenesis of SLE.MethodsThe clinical data and laboratory results of SLE patients were collected,and the systemic lupus erythematosus disease activity index(SLEDAI)was used to evaluate the activity of SLE patients.According to SLEDAI,patients were divided into the active group and the inactive group.Peripheral blood samples from SLE patients and healthy controls were collected.The levels of TCR αβ,TCR γδ and IL-17 in peripheral blood of patients with SLE and healthy people were detected by flow cytometry,and the percentage of αβ T cells,γδ T cells,IL-17+PBMC,IL-17+αβ T cells,IL-17+γβ T cells in peripheral blood of SLE patients and healthy people were compared,to explore the correlations between them and SLEDAI and to identify which kind of cells that mainly secrete IL-17.All the data were analyzed and processed by SPSS 20.0 software.The measured data were expressed as mean ±standard deviation and the counting data were expressed as percentage.It was significant when P value was less than 0.05.ResultsIn SLE patients,IL-17+αβ T cells and IL-17+γδ T cells accounted for(71 ±21)%and(12 ±11)%of IL-17+PBMC,respectively.In the control group,IL-17+αβ T cells and IL-17+γδ T cells accounted for(55 ±27)%and(11 ±11)%of IL-17+PBMC,separately.The percentages of IL-17+PBMC and IL-17+αβ T cells in SLE patients were significantly higher than those in the control group(P<0.01).The percentage of γδ T cells in peripheral blood of SLE patients was significantly lower than that of control group(P<0.01).The percentages of ap T cells,IL-17+PBMC,IL-17+αβT cells and IL-17+γδ T cells in patients with SLE were positively correlated with disease activity(rαβ T=0.46,Pαβ T<0.01;TIL-17+PBMC=0.47,PIL-17+PBMc＜0.01;rIL-17+αβT=0.53,PIL-17+αβY<0.01;rIL-17+γδT=0.42,PIL-17+γδT＜0.05).The percentage of y8 T cells was associated with primary lupus(r=0.43,P<0.05),but not with disease activity(r=-0.67,P>0.05).Conclusions1.IL-17 is mainly produced by αβ T cells,a few by γδ T cells in human PBMC.αβ T cells,IL-17+PBMC,IL-17+αβ T cells and IL-17+γδ T cells can be used to reflect the activity of SLE,suggesting that they may play an important role in the pathogenesis of SLE.2.The number of y8 T cells in peripheral blood of SLE patients is declining.It is speculated that the migration of γδ T cells from peripheral blood to skin mucosa in patients with SLE.This requires further study.Part2 Expression of IL-17-producing T lymphocytes in MRL/lpr MiceObjectiveSLE is a typical autoimmune connective tissue disease with unclear etiology and pathogenesis.MRL/lpr mice are one of the commonly used animal models to study the pathogenesis of SLE and evaluate the therapeutic methods and effects of lupus.In the first part of the clinical study,we found that IL-17 in PBMC of SLE patients was mainly secreted by αβ T cells.αβ T cells,IL-17+PBMC,IL-17+αβ T cells and IL-17+γδ T cells can be used to reflect the activity of SLE.The number of γδ T cells in peripheral blood of SLE patients is declining.In order to further confirm whether IL-17 and IL-17+T cells are involved in the pathogenesis of SLE and whether they are related to the involved tissues and organs,MRL/1pr mice were studied in this part.The expression of IL-17 in peripheral blood and kidneys and the expression ofαβ T cells and γδ T cells secreting IL-17 in spleens of MRL/lpr mice were detected.MethodsThe experimental animals were SPF grade 10-week-old female C57BL/6J mice and 10,16 and 22-week-old female MRL/lpr mice.After anesthesia,blood was taken from the removed eyeball,spleens and kidneys were removed,and the following experiments were carried out:1.Serum IL-17 level was determined by ELISA.2.Kidneys were stained with HE,the pathological changes of kidneys were observed under light microscope,and the expression of IL-17,IgG and C3 in kidneys were detected by immunohisto chemical method to evaluate the damage of kidneys in mice.3.The percentages of ap T cells and γδ T cells producing IL-17 in spleens were detected by flow cytometry.Results1.The level of serum IL-17 in MRL/lpr mice increased as compared to that in the control group and it increased with the increase of week age.2.No renal damage was found in MRL/lpr mice at 10 weeks old.Moderate proliferation of glomerular mesangial cells and endothelial cells was observed at 16 weeks of age,and diffuse increase of glomerular mesangial cells and stromal cells and infiltration of inflammatory cells were observed at 22 weeks of age.The renal intima proliferated and the lumen became narrower,and the expression of IL-17 was increased with the increase of age.In the control group,neither pathological damage nor IgG,C3 deposits were seen,and the expression of IL-17 was slight.The expression of IgG,C3 and IL-17 in the kidney tissues of MRL/lpr mice was apparently more than that in the control group,and with the increase of week age,it was progressively higher.3.The percentage of IL-17+αβ T cells and IL-17+γδ T cells in the spleen of MRL/lpr mice was significantly lower compared to control group(P<0.05).Conclusions1.MRL/lpr mice show lupus like renal histopathological changes.With the increase of week age,damages are gradually aggravated.2.IL-17A in serum and kidneys of MRL/lpr mice increases significantly with the increase of week age,suggesting that IL-17 may play a role in the pathogenesis of SLE.3.IL-17 is mainly produced by γδ T cells.The proportion of IL-17+T cells in spleens of MRL/lpr mice decreases. |
