Association of interleukin 22 gene polymorphisms and serum IL‐22 level with risk of systemic lupus erythematosus in a Chinese population

The aim of this study was to investigate the association between the single‐nucleotide polymorphisms (SNPs) of the interleukin 22 (IL‐22) gene and systemic lupus erythematosus (SLE) in a Chinese population. Three IL‐22 SNPs (rs2227485, rs2227513 and rs2227491) were genotyped using SNaPshot SNP genotyping assays and identified by sequencing in 314 SLE patients and 411 healthy controls. The IL‐22 level of serum was assessed by enzyme‐linked immunosorbent assay (ELISA) kits. Data were analysed by spss version 17.0 software. We found that rs2227513 was associated with an increased risk of SLE [AG versus AA: adjusted odds ratio (aOR) = 2·24, 95% confidence interval (CI) = 1·22–4·12, P = 0·010; G versus· A: adjusted OR = 2·18, 95% CI = 1·20‐3·97, P = 0·011]. Further analysis in patients with SLE showed that the AG genotype and G allele were associated with an increased risk of renal disorder in SLE (G versus A: aOR = 3·09, 95% CI = 1·30–7·33, P = 0·011; AG versus· AA: aOR = 3·25, 95% CI = 1·35–7·85, P = 0·009). In addition, the concentration of IL‐22 was significantly lower in the rs2227513 AG genotype compared with AA genotype (P = 0·028). These results suggest that rs2227513 polymorphism might contribute to SLE susceptibility, probably by decreasing the expression of IL‐22.     

Oestrogen up‐regulates interleukin‐21 production by CD4+ T lymphocytes in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which abnormal immune responses are mediated by tissue‐binding autoantibodies and immune complex deposition. Because most SLE patients are women of child‐bearing age, oestrogen has been suggested to play an important role in SLE pathogenesis. One proposed role is to induce B‐cell activation, culminating in increased autoantibody production. Interleukin‐21 (IL‐21) has been shown to be crucial in the differentiation of activated B cells into plasma cells. We therefore hypothesized that oestrogen up‐regulates IL‐21 production and induces subsequent B‐cell activation in SLE patients. Peripheral blood was obtained from 22 SLE patients and 16 healthy controls. Expression levels of IL‐21 and its receptor in serum, peripheral blood mononuclear cells, and CD4⁺ T cells were higher in SLE patients than in healthy controls. Exposure of CD4⁺ T cells from SLE patients to 17β‐oestradiol led to a dose‐ and time‐dependent increase in IL‐21 expression, which was abolished in the presence of mitogen‐activated protein kinase (MAPK) (MAPK kinase, p38, Jun N‐terminal kinase) inhibitors. B cells from healthy controls showed increased antibody production when they were co‐cultured with oestrogen‐treated CD4⁺ T cells from SLE patients. Treatment with IL‐21 antibody abrogated the increased antibody production of the co‐culture systems. This study revealed the association between oestrogen and IL‐21 in SLE patients. Oestrogen up‐regulates IL‐21 expression of CD4⁺ T cells via MAPK‐dependent pathways in SLE patients, which in turn induces increased antibody production by B cells.     

CD134 expression on CD4+ T cells is associated with nephritis and disease activity in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by a deviation of the immune system that involves T cell-dependent autoantibody production. The aim of this study was to investigate the role of co-stimulatory markers on T cells in this disease. Twenty-eight patients with SLE as defined by the American College of Rheumatology (ACR) criteria and 11 healthy controls were included into the study. Eleven patients had biopsy-proven lupus nephritis while 17 patients had no clinical evidence of lupus nephritis. Clinical disease activity was assessed according to the systemic lupus erythematosus disease index (SLEDAI). CD4+ T cell populations in the peripheral blood were analysed for the expression of co-stimulatory markers CD45RO, CD70, CD80, CD86, CD137, CD137L, CD134, CD152, CD154 and ICOS. SLE patients showed an increased frequency of peripheral CD4+ T cells expressing high levels of CD80, CD86 and CD134 compared to healthy controls (7.1 +/- 1.5% versus 1.7 +/- 0.9%; P < 0.005; 2.3 +/- 0.4% versus 1.0 +/- 0.2%; P = 0.008, 20.2 +/- 2.0% versus 10.6 +/- 1.9%; P < 0.005, respectively). Significantly higher levels of CD80 on CD4+ T cells were detected in SLE patients with lupus nephritis compared to patients without nephritis (11.9 +/- 3.3% versus 4.0 +/- 0.7%; P < 0.005). There was an increased presence of CD134+ CD4+ cells in SLE patients with lupus nephritis (27.5 +/- 4.0% versus 15.5 +/- 1.3%; P < 0.005). CD80 and CD134 expression was significantly correlated with SLEDAI (r = 0.42, P = 0.03; r = 0.56, P < 0.005). Co-stimulatory molecules on CD4+ T cells are associated with renal disease and disease activity in patients with systemic lupus erythematosus.     

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.     

Analysis of interleukin-23 receptor (IL23R) gene polymorphisms in systemic lupus erythematosus

The aim of this study was to evaluate the association between systemic lupus erythematosus (SLE) and polymorphisms in the interleukin-23 receptor (IL23R) gene, which have been previously found to be associated with two autoimmune diseases: inflammatory bowel disease and psoriasis. Our study includes 224 SLE patients and 342 healthy controls. The genotyping of IL23R variants was carried out using a polymerase chain reaction system with predeveloped TaqMan allelic discrimination assays. No statistically significant differences were observed between SLE patients and healthy controls with any of the IL23R genetic variants. In addition, we did not find any significant differences when we stratified SLE patients according to their clinical and demographic features. These results suggest that IL23R polymorphisms do not appear to play an important role in the susceptibility or severity of SLE in the Spanish population.     

Enhanced and persistent levels of interleukin (IL)‐17+CD4+ T cells and serum IL‐17 in patients with early inflammatory arthritis

Prognosis of patients with early inflammatory arthritis (EIA) is highly variable. The aim of this study was to compare, longitudinally and cross-sectionally, the levels of cytokine-expressing cells in peripheral blood (PB) from patients with EIA to those in established rheumatoid arthritis (RA) and healthy controls (HC). PB mononuclear cells from HC (n = 30), patients with EIA (n = 20) or RA (n = 38) were stimulated with phorbol myristate acetate (PMA)/ionomycin for 3 h, and stained for cell markers and cytokines. Serum cytokines and chemokines were measured by Luminex. Patients with EIA were reassessed at 6 and 12 months. The percentage of interleukin (IL)-17⁺interferon (IFN)-γ⁻CD4⁺ T cells [T helper type 17 (Th17)] was increased in RA and EIA versus HC. Serum IL-1β, IL-2, IL-4 IL-17 and macrophage inflammatory protein (MIP)-1α were increased in RA and EIA versus HC. IL-1Ra, IL-15 and IFN-α were increased in EIA versus HC. IL-6 and tumour necrosis factor (TNF)-α was increased in RA but not EIA versus HC. Disease activity scores in EIA patients improved over 12 months'' treatment. Th17 percentage at baseline was correlated with both rheumatoid factor (RF) titre and functional deficit at 12 months. Baseline levels of serum granulocyte–macrophage colony-stimulating factor (GM-CSF), IL-6 and IL-8 were correlated with Larsen score at 12 months. There were no significant changes in cytokine-expressing CD4⁺T cells over time, although the percentage of IL-6⁺ monocytes increased. IL-17⁺CD4⁺ T cells and serum IL-17 levels are increased in EIA. IL-6-expressing monocytes increase during the first year of disease, irrespective of disease-modifying anti-rheumatic drug (DMARD) therapy. We observed incomplete clinical responses, suggesting EIA patients need more intensive early therapy.     

Endogenous interleukin (IL)‐17A promotes pristane‐induced systemic autoimmunity and lupus nephritis induced by pristane

Interleukin (IL)-17A is increased both in serum and in kidney biopsies from patients with lupus nephritis, but direct evidence of pathogenicity is less well established. Administration of pristane to genetically intact mice results in the production of autoantibodies and proliferative glomerulonephritis, resembling human lupus nephritis. These studies sought to define the role of IL-17A in experimental lupus induced by pristane administration. Pristane was administered to wild-type (WT) and IL-17A^−/− mice. Local and systemic immune responses were assessed after 6 days and 8 weeks, and autoimmunity, glomerular inflammation and renal injury were measured at 7 months. IL-17A production increased significantly 6 days after pristane injection, with innate immune cells, neutrophils (Ly6G⁺) and macrophages (F4/80⁺) being the predominant source of IL-17A. After 8 weeks, while systemic IL-17A was still readily detected in WT mice, the levels of proinflammatory cytokines, interferon (IFN)-γ and tumour necrosis factor (TNF) were diminished in the absence of endogenous IL-17A. Seven months after pristane treatment humoral autoimmunity was diminished in the absence of IL-17A, with decreased levels of immunoglobulin (Ig)G and anti-dsDNA antibodies. Renal inflammation and injury was less in the absence of IL-17A. Compared to WT mice, glomerular IgG, complement deposition, glomerular CD4⁺ T cells and intrarenal expression of T helper type 1 (Th1)-associated proinflammatory mediators were decreased in IL-17A^−/− mice. WT mice developed progressive proteinuria, but functional and histological renal injury was attenuated in the absence of IL-17A. Therefore, IL-17A is required for the full development of autoimmunity and lupus nephritis in experimental SLE, and early in the development of autoimmunity, innate immune cells produce IL-17A.     

Preferential elimination of CD28+ T cells in systemic lupus erythematosus (SLE) and the relation with activation-induced apoptosis

CD28 on T cells provides a potent costimulatory signal for T cell activation. Down-regulation of CD28 on peripheral T cells has been reported in certain clinical conditions, but full studies on the mechanism and biological significance have not been performed. Our extensive phenotype analysis of peripheral blood lymphocytes (PBL) from SLE patients revealed that the absolute number of CD28⁺ T cells of both CD4 and CD8 phenotypes was selectively decreased, while that of CD28⁻ T cells was maintained. CD28⁺ T cells from SLE patients exhibited mostly normal proliferative responses to both CD28-dependent and -independent stimulations. In contrast, CD28⁻ T cells were hyporesponsive to anti-CD3 stimulation in both SLE and normal controls. These results implied that the selective decrease of CD28⁺ T cells in SLE does not result from a hyporesponsiveness of CD28⁺ T cells. To investigate the reason for the selective loss of CD28⁺ T cells, we determined the appearance of apoptotic cells in culture with or without anti-CD3 stimulation. Apoptotic cells defined by merocyanine (MC)540 were gradually increased from 12 h to 24 h. Anti-CD3-induced apoptosis of CD28⁺ T cells was significantly accelerated in SLE, whereas apoptosis of CD28⁻ T cells was hardly detected in both SLE and normal controls. Comparative analysis between CD28⁺ and CD28⁻ T cells on CD95 (Fas) and Bcl-2 expression, which are related to activation-induced cell death (AICD), did not show a major difference, although CTLA4, which has been demonstrated to transmit an apoptosis-inducing signal, was expressed only on CD28⁺ T cells. Our results suggest that CD28-mediated costimulation influences T cell susceptibility to AICD and may be involved in T cell lymphopenia in SLE.     

The effect of interleukin (IL)‐21 and CD4+CD25++ T cells on cytokine production of CD4+ responder T cells in patients with myasthenia gravis

Impairment of the suppressive function of regulatory T (T_reg) cells has been reported in myasthenia gravis (MG). In this study, cytokine‐related mechanisms that may lead to the defect of T_reg were investigated in patients with anti‐acetylcholine receptor antibody‐positive MG (AChR + MG). Proliferation and cytokine production of responder T (T_resp) cells in response to polyclonal activation were measured in a suppression assay. The effect of interleukin (IL)‐21 on suppression was evaluated in vitro in co‐culture. IL‐21 increased the proliferation of T_resp cells in T_resp/T_reg co‐cultures. T_resp cells from patients with MG secreted significantly lower levels of IL‐2. In patients with MG, IL‐2 levels did not change with the addition of T_reg to cultures, whereas it decreased significantly in controls. In T_resp/T_reg co‐cultures, IL‐4, IL‐6 and IL‐10 production increased in the presence of T_reg in patients. Interferon (IFN)‐γ was decreased, whereas IL‐17A was increased in both patient and control groups. IL‐21 inhibited the secretion of IL‐4 in MG and healthy controls (HC), and IL‐17A in HC only. The results demonstrated that IL‐21 enhances the proliferation of T_resp cells in the presence of T_reg. An effect of IL‐21 mainly on T_resp cells through IL‐2 is implicated.     

Differential serum cytokine profile in patients with systemic lupus erythematosus and posterior reversible encephalopathy syndrome

Systemic lupus erythematosus (SLE) patients are susceptible to the development of posterior reversible encephalopathy syndrome (PRES). The main theory concerning the physiopathology of PRES suggests that there is brain–blood barrier damage, which is associated with endothelial dysfunction, and characterized by vasogenic oedema. However, current evidence regarding its physiopathogenic mechanisms is quite scant. The aim of this study was to analyse the expression of different serum cytokines, as well as vascular endothelial growth factor (VEGF) and soluble CD40 ligand (sCD40L), in patients with PRES/systemic lupus erythematosus (SLE) and to compare them with levels in SLE patients without PRES and in healthy controls. We performed a transversal study in a tertiary care centre in México City. We included 32 subjects (healthy controls, n = 6; remission SLE, n = 6; active SLE, n = 6 and PRES/SLE patients, n = 14). PRES was defined as reversible neurological manifestations (seizures, visual abnormalities, acute confusional state), associated with compatible changes by magnetic resonance imaging (MRI). Serum samples were obtained during the first 36 h after the PRES episode and were analysed by cytometric bead array, Luminex multiplex assay or enzyme‐linked immunosorbent assay (ELISA). Interleukin (IL)‐6 and IL‐10 levels were significantly higher in PRES/SLE patients (P = 0·013 and 0·025, respectively) when compared to the other groups. Furthermore, IL‐6 and IL‐10 levels displayed a positive correlation (r = 0·686, P = 0·007). There were no differences among groups regarding other cytokines, sCD40L or VEGF levels. A differential serum cytokine profile was found in PRES/SLE patients, with increased IL‐6 and IL‐10 levels. Our findings, which are similar to those described in other neurological manifestations of SLE, support the fact that PRES should be considered among the SLE‐associated neuropsychiatric syndromes.     

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.     

CD226在系统性红斑狼疮患者T淋巴细胞亚群上的表达

目的：研究CD226在SLE患者外周血T淋巴细胞亚群上的表达，以阐明CD226抗原在SLE患者体内T细胞活化中作用以及与SLE发病的关系。方法：31例SLE患者和30例健康志愿者外周血单个核细胞，在体外培养72h后，三色荧光标记的单克隆抗体染色，利用流式细胞仪测定T细胞亚群细胞表面CD226抗原的表达。结果；SLE患者组的CD3^ 、CD4^ 、CD8^ T淋巴细胞上CD226^ 表达均高于正常对照组（P＜0．01）；活动期SLE组、静止期SLE组的CD3^ 、CD4^ 、CD8^ T细胞上CD226^ 表达均显著高于对照组（P＜0．01），而活动期与静止期患者之间T细胞亚群上CD226^ 表达则无显著性差异（P＞0．05）。SLE患者CD3^ 、CD4^ 、CD8^ T细胞CD226^ 抗原表达水平与SLEDAI之间无明显相关性（P＞0．05）。结论：SLE患者体内存在T细胞亚群异常活化；活动期、静止期SLET淋巴细胞CD226^＋表达均增高，CD226^ 可能参与了SLE的免疫发病。     

系统性红斑狼疮患者外周血CD4+和CD8+T细胞PD-1的表达和意义

目的 探讨程序性死亡分子1 (PD-1)在系统性红斑狼疮(SLE)患者外周血CD4+和CD8+T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T细胞亚群表面PD-1表达水平,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+和CD8+T细胞表面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 SLE活动组CD4+T细胞PD-1表达水平高于健康对照组和不活动组,差异均有统计学意义(P＜0.05).SLE活动组、稳定组CD8+T细胞PD-1表达水平均高于健康对照组,差异有统计学意义(P＜0.05).狼疮肾炎患者CD4+PD-1+和CD8+PD-1+T细胞分别高于无狼疮肾炎患者(P＜0.01).SLE患者中抗dsDNA抗体、抗Sm抗体、抗核小体抗体阳性组外周血CD4+和CD8+T细胞PD-1表达水平均高于对应阴性组.SLE患者CD4+和CD8+T细胞PD-1表达百分率与SLE疾病活动度指数(SLEDAI)、尿蛋白定量呈正相关,与补体C3呈负相关.结论 SLE患者外周血CD4+和CD8+T细胞PD-1表达异常,与SLEDA1和自身抗体产生有明确的相关性.     

IL-10 stimulates production of platelet-activating factor by monocytes of patients with active systemic lupus erythematosus (SLE)

IL-10 displays modulatory properties on the synthesis of platelet-activating factor (PAF), a potent inflammatory mediator of vascular injury. Despite the fact that IL-10 is considered to be an anti-inflammatory cytokine, IL-10 levels correlate with disease activity in SLE. Moreover, in SLE IL-10 is unable to exert its immunosuppressive and anti-inflammatory effects. We have investigated the ability of IL-10 to stimulate PAF production from monocytes of SLE patients. Spontaneous and IL-10-stimulated PAF production by peripheral blood monocytes was measured in active (n = 13) and inactive (n = 14) SLE patients and in 15 normal control subjects. We observed that monocytes derived from patients with active SLE, but not from controls or inactive SLE, spontaneously produced significant amounts of PAF. Moreover, IL-10 enhanced the synthesis of PAF from monocytes of active SLE patients only. IL-10-induced PAF production correlated with the severity of the disease and with the extent of proteinuria. These results indicate that IL-10 only stimulates the synthesis of PAF from monocytes of SLE patients when immunologically active, suggesting that IL-10 may possess a paradoxical proinflammatory effect in SLE by promoting the production of PAF, a secondary mediator of inflammation.