Regulatory T cells in systemic lupus erythematosus

Systemic lupus erythematosus (SLE), an autoimmune disease, develops when immunologic self‐tolerance fails. Treg cells are a subset of CD4⁺ T cells that maintain self‐tolerance by suppressing autoreactive lymphocytes. Defects in Treg cells are therefore considered to be an aspect of SLE pathogenesis. Nevertheless, reports on the numbers and function of Treg cells in SLE are contradictory and the definitive role of Treg cells in SLE remains unclear. In this review, we summarize findings from murine models and ex vivo experiments, which provide insights into the mechanisms that result in the breakdown of tolerance. We also include recent findings about Treg‐cell subsets and their markers in human SLE. The identification of unique markers to identify bona fide Treg cells, as well as therapies to reconstitute the balance between Treg cells and autoreactive T cells in SLE, are the future challenges for SLE research.     

T cells in the pathogenesis of systemic lupus erythematosus

Recent studies in patients with systemic lupus erythematosus (SLE) have demonstrated that autoantigen-reactive T cells can be isolated from peripheral blood and that such cells can support autoantibody production ex vivo, suggesting that they may have a central role in the pathogenesis of disease. In addition, recent work has identified and characterized signaling abnormalities in T cells from SLE that may be fundamental to the disease. This review will examine the role of T cells in the pathogenesis of SLE and it will consider pathogenic mechanisms by which T cells escape normal of immunological tolerance. The focus will be on recent studies characterizing autoantigen-reactive human T cells and signaling abnormalities identified in T cells from patients with SLE.     

茯苓多糖对系统性红斑狼疮患者Th17/Treg平衡的影响

目的:研究茯苓多糖对系统性红斑狼疮(SLE)患者外周血辅助性T细胞17(Th17)/调节性T细胞(Treg)平衡的免疫调节作用。方法:选取45例SLE患者和35例健康对照者,应用磁珠分选法分离外周血CD4~+ T细胞,流式细胞术检测CD4~+ T细胞中Th17和Treg细胞的比例。用茯苓多糖分别处理健康对照者及患者的CD4~+ T细胞,MTT法检测细胞活力以测定茯苓多糖毒性,ELISA检测细胞中白细胞介素17(IL-17)、IL-6、IL-10及转化生长因子β(TGF-β)的含量,RT-q PCR和Western blot法分别测定维甲酸相关孤儿受体γt(RORγt)与叉头框蛋白P3(Foxp3)的mRNA和蛋白表达水平。结果:与健康对照组相比,SLE患者的Th17细胞比例显著升高,Treg细胞比例明显降低(P0.05)。用100μg/L的茯苓多糖处理SLE患者CD4~+ T细胞,与空白对照组相比,IL-17和IL-6的含量显著降低,IL-10和TGF-β的含量明显上升(P0.05);RORγt的mRNA和蛋白表达显著下降,同时Foxp3的表达在mRNA和蛋白水平上明显增加(P0.05);并且Th17/Treg的比值降低(P0.05)。结论:茯苓多糖可以通过升高Treg并降低Th17细胞的比例,对SLE起到一定的治疗作用。     

钙调神经磷酸酶-活化T细胞核因子与系统性红斑狼疮

系统性红斑狼疮是一种以多种自身抗体产生为特点的侵犯多系统多脏器的自身免疫性疾病,其发病机制尚未明确,目前认为T淋巴细胞异常是SLE的发病的关键.钙调神经磷酸酶-活化T细胞核因子信号通路作为T细胞内重要的生物信号转导通路,在T细胞活化中起到调节枢纽的作用,了解CaN/NFAT信号途径在SLE中的作用及目前相关主要治疗药物的研究现状可为SLE的基础研究及临床治疗提供依据.     

系统性红斑狼疮T细胞分子信号转导异常对疾病诊断及治疗的意义

系统性红斑狼疮(systemic lupus erythematosus,SLE)是一种典型的系统性自身免疫性疾病,T淋巴细胞在机体大量自身抗原刺激下,信号传递及基因表达出现多种特异性缺陷,在疾病发生发展中起到关键作用。CD3复合物的重构及胞膜表面脂筏的大量聚集使SLET细胞的活化阈降低,胞内信号级联紊乱;同时,聚集的脂筏中黏附分子表达上调促使T细胞向靶组织定向趋化;信号转导紊乱导致转录因子表达改变,DNA甲基化异常引发基因表达失衡。由此,功能异常的T细胞中改变的多种信号分子可以作为诊断和治疗SLE的潜在性分子靶标。     

Abnormal CTLA‐4 function in T cells from patients with systemic lupus erythematosus

CTLA‐4 is a critical gatekeeper of T‐cell activation and immunological tolerance and has been implicated in patients with a variety of autoimmune diseases through genetic association. Since T cells from patients with the autoimmune disease systemic lupus erythematosus (SLE) display a characteristic hyperactive phenotype, we investigated the function of CTLA‐4 in SLE. Our results reveal increased CTLA‐4 expression in FOXP3^? responder T cells from patients with SLE compared with other autoimmune rheumatic diseases and healthy controls. However, CTLA‐4 was unable to regulate T‐cell proliferation, lipid microdomain formation and phosphorylation of TCR‐ζ following CD3/CD28 co‐stimulation, in contrast to healthy T cells. Although lupus T cells responded in vitro to CD3/CD28 co‐stimulation, there was no parallel increase in CTLA‐4 expression, which would normally provide a break on T‐cell proliferation. These defects were associated with exclusion of CTLA‐4 from lipid microdomains providing an anatomical basis for its loss of function. Collectively our data identify CTLA‐4 dysfunction as a potential cause for abnormal T‐cell activation in patients with SLE, which could be targeted for therapy.     

Systemic lupus erythematosus,regulatory T cells and pregnancy

Systemic lupus erythematosus (SLE) is the most common autoimmune disease affecting women of reproductive age and is associated with poor maternal and fetal outcomes. CD4⁺CD25⁺ Treg cells are a subset of T lymphocytes with potent immunosuppressive activity that play crucial roles in controlling immunological self tolerance. Evidence suggests that they are augmented in pregnancy, especially in the first trimester, suggesting an important role in early placental development. The literature describing Treg cells in SLE is conflicting, but SLE is associated with reduced numbers and functionally defective Treg cells, which may predispose pregnant women with the disease to pregnancy complications. This article discusses the role of Treg cells in SLE and pregnancy, and how these cells may contribute to poor pregnancy outcome in SLE-affected women.     

Caspase-8信号分子对SLE患者T细胞亚群的双向调节作用研究

目的 分析SLE患者外周血T细胞内活化Caspase-8、Caspase-3和T细胞膜上Fas、CD69以及外周血中Foxp3 CD4 CD25 调节性T细胞的表达,探讨他们在SLE患者免疫失衡中的作用.方法 用流式细胞术检测活化Caspase-8、Caspase-3和Fas、CD69以及Foxp3 CD4 CD25 Treg的表达.结果 与健康对照相比,SLE患者外周血CD3 CD4 T细胞上Fas表达显著升高(P＜0.05),无论稳定期或活动期SLE患者CD3 CD4 T细胞和CD3 CD8 T细胞中活化Caspase-8的表达均显著增加(P＜0.05),且稳定期和活动期SLE患者CD3 CD8 T细胞中活化Caspase-8的表达高于其在CD3 CD4 T细胞中的表达(P＜0.05);但是仅活动期SLE患者T细胞内活化Caspase-3表达增加(P＜0.05),同时稳定期和活动期SLE患者CD3 CD4 T细胞中活化Caspase-3的表达高于其在CD3 CD8 T细胞中的表达(P＜0.05).同时SLE患者CD3 CD8 T细胞上CD69表达率升高(P＜0.05),但是CD69在CD3 CD4 T细胞上的表达率与健康对照相比无显著性差异(P＞0.05).SLE患者外周血中Foxp3 CD4 CD25 Treg比例显著低于健康对照(P＜0.05).结论 Caspase-8介导的信号事件同时参与诱导SLE患者淋巴细胞的凋亡与活化,促使SLE患者体内免疫反应向Th2极化,同时由于SLE患者外周血中Foxp3 CD4 CD25 Treg表达降低所介导的免疫抑制效应缺陷,他们共同作用促使SLE患者外周免疫平衡障碍.     

HLA DRB1*1503 allelic haplotype predominance and associated immunodysregulation in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic, relapsing, and remitting disease affecting primarily African American females of child bearing age. Familial aggregation of this disease suggests that at least part of the susceptibility for this disease is genetic, although environmental and hormonal influences are also likely to play a role. Early studies of genetic susceptibility to SLE revealed several of the major histocompatibility complex molecules, namely HLA DR, to be linked to SLE. Meta-analysis of genome scans has yielded loci significant for lupus patients, one of which includes the MHC region.Regulatory T cells are immunoregulatory cells that modulate activated immune cells. These cells play a large role in homeostasis of the immune responses and maintenance of immunologic tolerance, i.e., prevention of autoimmunity. Decreased numbers of regulatory T cells have been described in many autoimmune diseases, including systemic lupus erythematosus.Autoantibody production in systemic lupus erythematosus and the resulting immune complex formation and complex deposition into tissues are arguably the central core of immune dysregulation leading to disease manifestations and symptoms. Inability of the immune system to recognize and inhibit autoreactive immune cells in this particular autoimmune disease may be the result of inappropriate numbers and function of regulatory T cells.This study aims to characterize the immune cell population in patients from our community suffering from systemic lupus erythematosus and to prove that these patients exhibit a unique cellular profile compared to healthy age, race and gender matched control subjects. Surprisingly, our findings demonstrate that patients from the local Mississippi area exhibit increased proportions of CD25⁺ FoxP3⁺ regulatory T cells and CD25⁺ FoxP3⁻ T cells (of CD45⁺ CD3⁺ CD4⁺ helper T cells) as compared to healthy controls.HLA tissue-typing of these lupus patients revealed a prominent subgroup (~ 30%) of patients possessing the HLA DRB1*1503 allele. The investigation of this subgroup demonstrated regulatory T cell composition similar to that of the total lupus group and to that of the non-HLA DRB1*1503 subgroup.Genetic analysis for molecular gene expression levels of various lupus-associated genes by real-time PCR demonstrated a unique profile as compared to healthy controls. Increased gene expression of FoxP3 together with decreased gene expression levels of GATA3, TNFAIP3, and TNFSF4 suggest that variations in gene products compared to healthy controls may be playing a role in the immune cell dysregulation and disproportionate CD25⁺ FoxP3⁺ regulatory T cells.     

Curcumin: A natural modulator of immune cells in systemic lupus erythematosus

Curcumin is a polyphenol natural product isolated from turmeric, interacting with different cellular and molecular targets and, consequently, showing a wide range of pharmacological effects. Recent preclinical and clinical trials have revealed immunomodulatory properties of curcumin that arise from its effects on immune cells and mediators involved in the immune response, such as various T-lymphocyte subsets and dendritic cells, as well as different inflammatory cytokines. Systemic lupus erythematosus (SLE) is an inflammatory, chronic autoimmune-mediated disease characterized by the presence of autoantibodies, deposition of immune complexes in various organs, recruitment of autoreactive and inflammatory T cells, and excessive levels of plasma proinflammatory cytokines. The function and numbers of dendritic cells and T cell subsets, such as T helper 1 (Th1), Th17, and regulatory T cells have been found to be significantly altered in SLE. In the present report, we reviewed the results of in vitro, experimental (pre-clinical), and clinical studies pertaining to the modulatory effects that curcumin produces on the function and numbers of dendritic cells and T cell subsets, as well as relevant cytokines that participate in SLE.     

系统性红斑狼疮患者外周血CD4+CD25high Tr和 CD4+CD25low T细胞PD-1表达的分析和意义

目的 探讨PD-1(programmed death-1)在系统性红斑狼疮(systemic lupus erythematosus,SLE)患者外周血CD4+ CD25high调节性T细胞(regulatory T cell,Tr)和CD4+ CD25lowT细胞上的表达及临床意义.方法 应用流式细胞仪检测51例SLE患者和38例健康对照者外周血CD4+ CD25high Tr和CD4+ CD25lowT细胞表面PD-1表达水平,同时收集SLE患者临床表现、实验室检查数据,比较SLE稳定组、活动组和健康对照组以及狼疮肾炎组和无狼疮肾炎组之间CD4+ CD25 high Tr和CD4+CD25lowT细胞表PD-1表达的百分比,并分析其与临床表现及实验室检查数据的相关性.结果 (1)SLE活动组和稳定组外周血CD4+ CD25 high Tr和CD4+ CD25lowT细胞的百分率均低于对照组.(2)SLE活动组和稳定组外周血CD4+ CD25 highTr表达PD-1的百分率均高于对照组.SLE稳定组和对照组外周血CD4+ CD25lowT细胞表达PD-1的百分率均高于活动组.(3)狼疮肾炎患者外周血CD4+CD25highTr表达PD-1的百分率高于无狼疮肾炎患者.而狼疮肾炎患者CD4+ CD25lowT细胞表达PD-1的百分率低于无狼疮肾炎患者.(4) CD4+CD25high PD-1+T细胞百分率与SLEDAI评分呈正相关;CD4+ CD25high Tr、CD4+CD25lowPD-1+T细胞百分率与SLEDAI评分呈负相关.结论 SLE患者外周血中CD4+ CD25high Tr、CD4+ CD25lowT细胞以及它们表面PD-1表达异常,并且与疾病活动性相关,PD-1/PD-L1信号通路可能对CD4+CD25highTr、CD4+CD25lowT细胞的数量和功能有影响.     

钾通道在系统性红斑狼疮T细胞中的作用研究

目的:研究SLE患者外周血活化T细胞中Kv1.3和IKCa1通道的表达情况,以及阻断Kv1.3通道后对SLE患者T细胞增殖的影响。方法:①病例选择:SLE患者33例,健康对照组12例;②分离外周血T细胞,采用抗CD3单克隆抗体刺激T细胞活化,培养72小时;③荧光实时定量RT-PCR检测SLE患者活化T细胞中Kv1.3和IKCa1通道的mRNA表达;④CCK-8法检测阻断Kv1.3通道对SLE患者T细胞增殖的影响;⑤应用统计软件SPSS17.0进行数据统计分析;对Kv1.3和IK-Ca1通道mRNA相对表达量与补体C3、C4、抗dsDNA抗体、SLEDAI积分及尿蛋白间进行相关性分析。结果:①SLE患者外周血T细胞活化后Kv1.3通道mRNA的表达与正常对照组相比明显增高(P<0.0001),IKCa1通道mRNA的表达与正常对照组相比降低(P=0.006),SLE患者Kv1.3及IKCa1 mRNA表达水平均与补体C3、C4、抗dsDNA抗体、SLEDAI积分及尿蛋白无相关性。②Kvl.3通道阻断剂ShK可明显抑制SLE患者外周血T细胞的增殖(P<0.001)。结论:Kv1.3通过是SLE患者TEM细胞活化的主要离子通道,Kv1.3通道可成为SLE免疫治疗的一个新起点。     

Immunosuppressive therapy modulates T lymphocyte gene expression in patients with systemic lupus erythematosus

To evaluate the T-cell large-scale differential gene expression in systemic lupus erythematosus (SLE) patients presenting with glomerulonephritis we studied SLE patients before and after immunosuppressive treatment. Large-scale gene expression of peripheral blood mononuclear T cells was evaluated using cDNA microarray nylon membranes containing 5184 cDNAs. Data were analysed using the SAM and Cluster and Treeview software. When untreated patients were compared to healthy individuals, 38 genes, most of them located on chromosomes 1, 3, 6, 17 and 19, were repressed, and when untreated patients were compared to treated ones, 154 genes, located on chromosomes 1, 6, 7, 12 and 17, were induced. In terms of biological function of coded proteins, the differentially expressed genes were associated with apoptosis, cell cycle, chromosomal scaffold, cytokine/chemokine, DNA repair/replication, Golgi/mitochondrial proteins, mRNA processing, signalling molecules and tumour suppressors. Two autoantigen genes related to RNA splicing (small nuclear riboprotein 70,000 MW-U1 SNR, and splicing factor 3a, 60,000 MW), and the tetranectin-plasminogen-binding protein were repressed. The Fc fragment of immunoglobulin G low affinity IIb, apoptotic protease activating factor-1, two subunits of cytochrome c, caspase 8, complement C5a, HLA-DRA, HLA-DQB1, transforming growth factor-beta receptor II, small nuclear ribonucleoprotein polypeptide N (Sm protein N) genes, heterogeneous nuclear riboprotein-C, and argininosuccinate lyase genes, among others, were induced. A total of 10 genes were repressed in untreated patients and induced in treated ones, among them tumour necrosis factor (ligand) superfamily member 9, tumour protein p53, mannosidase alpha class IA, and CD22. Although some of these differentially expressed genes are typically expressed in B cells, CD22 and CD32 have also been reported in T cells and may provide regulatory signals to B cells. Assessment of differential gene expression may provide hybridization signatures that may identify susceptibility, diagnostic and prognostic markers of SLE.     

Therapeutic efficacy of anti-CD19 CAR-T cells in a mouse model of systemic lupus erythematosus

Dysregulated B-cell activation plays pivotal roles in systemic lupus erythematosus (SLE), which makes B-cell depletion a potential strategy for SLE treatment. The clinical success of anti-CD19 CAR-T cells in treating B-cell malignancies has attracted the attention of researchers. In this study, we aimed to investigate the feasibility of applying anti-CD19 CAR-T cell therapy to SLE treatment in a mouse disease model. We constructed murine anti-CD19 CARs with either CD28 or 4-1BB as the intracellular costimulatory motif and evaluated the therapeutic function of the corresponding CAR-T cells by infusing them into MRL-lpr mice. Furthermore, anti-CD19 CAR-T cells were transferred to MRL-lpr mice before the onset of disease to determine their role in SLE prevention. According to our observations, compared with antibody treatment, the adoptive transfer of our anti-CD19 CAR-T cells showed a more sustained B-cell-depletion effect in MRL-lpr mice. The transfer of syngeneic anti-CD19 CAR-T cells not only prevented disease pathogenesis before the onset of disease symptoms but also displayed therapeutic benefits at a later stage after disease progression. We also tried to optimize the treatment strategy and found that compared with CAR-T cells with the CD28 costimulatory motif, CAR-T cells with the 4-1BB costimulatory motif showed better therapeutic efficiency without cell enrichment. Taken together, these results show that anti-CD19 CAR-T cell therapy was effective in the prevention and treatment of a murine model of SLE, indicating its potential for clinical use in patients.     

Two separate effects contribute to regulatory T cell defect in systemic lupus erythematosus patients and their unaffected relatives

Forkhead box P3 (FoxP3)⁺ regulatory T cells (T_regs) are functionally deficient in systemic lupus erythematosus (SLE), characterized by reduced surface CD25 [the interleukin (IL)‐2 receptor alpha chain]. Low‐dose IL‐2 therapy is a promising current approach to correct this defect. To elucidate the origins of the SLE T_reg phenotype, we studied its role through developmentally defined regulatory T cell (T_reg) subsets in 45 SLE patients, 103 SLE‐unaffected first‐degree relatives and 61 unrelated healthy control subjects, and genetic association with the CD25‐encoding IL2RA locus. We identified two separate, uncorrelated effects contributing to T_reg CD25. (1) SLE patients and unaffected relatives remarkably shared CD25 reduction versus controls, particularly in the developmentally earliest CD4⁺FoxP3⁺CD45RO^–CD31⁺ recent thymic emigrant T_regs. This first component effect influenced the proportions of circulating CD4⁺FoxP3^highCD45RO⁺ activated T_regs. (2) In contrast, patients and unaffected relatives differed sharply in their activated T_reg CD25 state: while relatives as control subjects up‐regulated CD25 strongly in these cells during differentiation from naive T_regs, SLE patients specifically failed to do so. This CD25 up‐regulation depended upon IL2RA genetic variation and was related functionally to the proliferation of activated T_regs, but not to their circulating numbers. Both effects were found related to T cell IL‐2 production. Our results point to (1) a heritable, intrathymic mechanism responsible for reduced CD25 on early T_regs and decreased activation capacity in an extended risk population, which can be compensated by (2) functionally independent CD25 up‐regulation upon peripheral T_reg activation that is selectively deficient in patients. We expect that T_reg‐directed therapies can be monitored more effectively when taking this distinction into account.     

Immunopathogenesis of systemic lupus erythematosus and rheumatoid arthritis: the role of aberrant expression of non‐coding RNAs in T cells

Non‐coding RNAs (ncRNAs), including microRNAs (miRNAs) and long non‐coding RNAs (lncRNAs), are RNA molecules that do not translate into protein. Both miRNAs and lncRNAs are known to regulate gene expression and to play an essential role in T cell differentiation and function. Both systemic lupus erythematosus (SLE), a prototypic systemic autoimmune disease, and rheumatoid arthritis (RA), a representative disease of inflammatory arthritis, are characterized by a complex dysfunction in the innate and adaptive immunity. T cells play a central role in cell‐mediated immune response and multiple defects in T cells from patients with SLE and RA have been observed. Abnormality in T cell signalling, cytokine and chemokine production, T cell activation and apoptosis, T cell differentiation and DNA methylation that are associated closely with the aberrant expression of a number of miRNAs and lncRNAs have been implicated in the immunopathogenesis of SLE and RA. This review aims to provide an overview of the current state of research on the abnormal expression of miRNAs and lncRNAs in T cells and their roles in the immunopathogenesis of SLE and RA. In addition, by comparing the differences in aberrant expression of miRNAs and lncRNAs in T cells between patients with SLE and RA, controversial areas are highlighted that warrant further investigation.     

Conserved anti-proliferative effect and poor inhibition of TNFα secretion by regulatory CD4CD25 T cells in patients with systemic lupus erythematosus

A role of natural regulatory CD4⁺CD25⁺ T cells in peripheral tolerance has been established, but a causative role of these cells has not been proved in human autoimmune diseases. Functional alterations have been reported in arthritis and contradictory results have been published in systemic lupus erythematosus (SLE). In this study, the CD4⁺CD25⁺ T cell function was studied in 12 SLE patients (6 with only antimalarials and 6 also with corticoids treatment) in parallel to 12 healthy controls. CD4⁺CD25⁻ T cells were cocultured with allogenic monocyte derived dendritic cells (MDDC) and CD4⁺CD25⁺ T cells were added. Proliferation was measured by [³H]-thymidine incorporation and TNFα secretion was assessed by ELISA. A better anti-proliferative function of CD4⁺CD25⁺ T cells was found in patients than in controls (p = 0.009), whereas higher TNFα secretion was found in patients (p = 0.028). There were no significant differences regarding treatment. In summary, CD4⁺CD25⁺ T cells from SLE patients showed an undamaged anti-proliferative function. Our results and other authors' have not proved a SLE causative role for CD4⁺CD25⁺ T cells. The reduced inhibitive function on TNFα secretion found in patients could have some implications in lupus pathogenesis.