类风湿性关节炎与感染

类风湿性关节炎(RA)的病因至今尚不清楚。近年来国外的研究资料证实,RA患者血清中存在某些抗病原微生物的抗体,如抗分枝杆菌、奇异变形杆菌、肺炎克雷白杆菌、疟原虫等的抗体,据此推测RA的病因可能与感染有关。     

EBV感染与类风湿性关节炎发病机制关联性的研究进展

类风湿性关节炎(Rheumatoid Arthritis,RA)的发病机制尚未明确,但遗传因素和环境因素在RA的发病中起着重要作用。近三十年来,RA的发病机制与EBV(Epstein-Barr virus,又称HHV-4)感染的关联性已成为研究热点。诸多文献表明,RA患者的EBV抗体滴度高于正常对照组,血清中还存在着抗瓜氨酸化EBV肽的抗体,而RA患者体内的淋巴细胞却对EBV的应答呈现免疫低反应性。采用PCR、原位杂交和免疫组化等技术发现RA患者滑膜同样存在着EBV抗体及遗传物质,尽管有些研究结果仍不一致。一些EBV抗体与患者自身组织和细胞间存在氨基酸序列的同源性,如HLA-DRB1*0401/0405与EBV gp110糖蛋白存在同源序列的QKRAARA。基于上述证据提示EBV可能通过"分子模拟(molecular mimicry)"机制介导了RA的发病。另外,SAP(signallinglymphocyte activation molecule-associated protein,信号淋巴细胞活化分子相关蛋白)信号途径的异常可能也是EBV导致RA发生发展的分子生物学机制之一。尽管EBV同RA之间存在着诸多的联系,但仍需提供更多的实验证据阐明它们的因果关系。揭示RA发病与EBV感染的免疫学本质对临床防治RA有着十分重要的科学意义。     

基于无菌动物研究肠道微生物与类风湿关节炎发病相关性

肠道微生物与宿主的生长发育、免疫、代谢等方面均密切相关,但肠道菌群与宿主之间复杂的相互作用在很大程度上仍然是未知的。目前无菌动物已成为探索肠道微生物与宿主相互作用的重要工具,多项研究使用无菌动物模型探讨肠道菌群在宿主代谢、机体免疫系统的发育和成熟等方面的作用,其中包括肠道菌群在自身免疫性疾病发病及预后中的作用。研究发现,肠道菌群作为环境因素之一可能参与类风湿关节炎(rheumatoid arthritis,RA)发病,然而其因果关系未明。本文将对使用无菌动物探讨肠道微生物参与类风湿关节炎发病的相关性研究作一综述,为进一步深入研究肠道菌群在RA发病中的作用及机制研究提供理论依据。     

IL-15在类风湿关节炎中的作用的研究进展

细胞因子在类风湿关节炎(rheumatoid arthritis,RA)的发病机制中发挥着十分显著的作用。近年来,白细胞介素—15 (interleukin-15,IL-15)在RA中的作用受到研究者广泛关注。最新研究表明,IL-15参与了RA的多个发病环节,在RA的进展中扮演着重要的角色。     

感染组学 (infectomics) ———对感染性疾病的总体性和综合性研究

在感染性疾病的范畴内,目前急需一个能有效地、精确地和综合性地研究微生物感染的结构性和功能性基因组学和蛋白质组学 ( 感染组学 ) 的全面方法. 新的方法 ( 如 DNA 和蛋白质微阵列 ) 和传统方法 ( 如分子克隆、 PCR 、基因敲除,加进 (knockin) 和反义术等 ) 的结合将有助于克服今天的困难. 在感染时,微生物及其宿主的全部表型改变 ( 感染组 ) 均由微生物病原体及其宿主的基因组所编码,并在特异的微生物 - 宿主相互作用时的某些环境条件下表达. 微生物及其宿主的全部药物反应 ( 药理组 ) 可用基因组或蛋白质组的方法检出. 分析基因型和表型或表达形式的全基因组方法将最终导致对微生物的发病机理、感染性疾病的快速诊断和控制感染的新策略的全面研究. 感染性疾病中最基本的问题是,如何全面地和综合性地应用感染组学,来了解微生物病原体及其宿主的相互作用.     

细胞因子与类风湿关节炎的研究进展

类风湿关节炎(RA)是一种慢性、多系统的以关节的炎症损害为主要特点的自身免疫性疾病。其发病过程与多种细胞因子有关,包括TNF-α、IL-1、MMPS、IL-6、IL-17、IL-18等,这些细胞因子在RA的发病进程中起了很重要的作用,可作为治疗RA的新靶点。     

类风湿关节炎患者血清血红素加氧酶-1水平与间质性肺疾病的关系

为了研究类风湿关节炎(rheumatoid arthritis,RA)患者血清中血清血红素加氧酶-1(heme oxygenase-1,HO-1)的水平及其与RA继发性间质性肺疾病(interstitial lung disease,ILD)之间的关系,探讨RA的发病机制及RA继发ILD的相关因素,我们选择了64例RA患者,其中单纯的RA患者36例,RA并发性ILD患者28例;健康对照者32例。我们利用酶联免疫吸附实验(enzyme linked immunosorbent assay,ELISA)和免疫印迹法(immunoblotting,IB)检测了各组患者血清中HO-1的含量,同时,通过对各组患者免疫学指标(包括免疫球蛋白IgG,IgA,IgM,α2-球蛋白以及γ球蛋白的差异)、各组临床相关指标(包括C反应蛋白(C-reactive protein,CRP);类风湿因子(rheumatoid factor,RF);晨僵时间,关节肿痛数,抗环胍氨酸蛋白抗体(cyclic peptide containing citrulline,CCP)阳性率、红细胞沉降率(erythrocyte sedimentation rate,ESR))以及疾病活动度评分(disease activity score 28,DAS28)的差异进行了比较和相关性分析,我们发现,总RA组患者血清HO-1含量((6.34±0.71)ng/L)显著性高于健康对照组((0.53±0.17)ng/L)(p0.05),且RA并发性ILD组患者血清HO-1的含量为(9.52±1.14)ng/L显著性高于单纯RA组((3.92±0.24)ng/L)(p0.05),表明HO-1可能参与RA的发病,并且在RA继发ILD的发生发展中发挥一定作用。我们的研究为类风湿关节炎及其继发性间质性肺疾病的发病机制的研究及临床治疗提供了新的理论依据。     

EB病毒与类风湿关节炎的相关性分析

目的:检测EB病毒VCA-IgA抗体在类风湿关节炎(RA)患者外周血中的表达,探讨EB病毒与RA的相关性.方法:分别采用酶联免疫吸附试验(ELISA)法和实时定量PCR方法检测EB病毒VCA-IgA抗体和EB病毒DNA载量.同时分析EB病毒VCA-IgA抗体与RA患者的实验室指标抗CCP抗体、类风湿因子(RF)和血沉(ESR)的相关性.结果:223例SLE患者中,32例为EBV-VCA-IgA抗体阳性,259例健康对照者中16例阳性,KA患者阳性率明显高于对照组(14.35%VS 6.17%;P<0.01).RA患者EB病毒栽量也明显高于对照组.EB病毒VCA-IgA抗体阳性与抗CCP抗体、RF和ESR不相关.结论:EB病毒感染与RA相关.EB病毒VCA-IgA抗体阳性者有较高的DNA载量,RA的发病危险性亦高,EB病毒重新活化与RA活动有关.     

菌群变化对类风湿关节炎的影响

目前,对于类风湿关节炎(rheumatoid arthritis,RA)发病机制的研究虽然并不完全清晰,但过去20多年的研究已经使我们对RA的了解增加了很多。遗传因素对RA有很大的影响,但不足以完全解释RA的发生。随着对菌群与RA关系的了解增多,使我们认识到可以利用调节人体菌群的方法,来改善宿主黏膜及更远处的免疫环境以改善RA。目前研究已表明,RA与多个部位的菌群都有一定的关系。本研究将以RA的发病机制与影响因素为基础,对人体口腔、肺部和肠道的菌群变化对类风湿关节炎的影响以及益生菌的治疗作用进行综述。     

Th1、Th2和Th17型细胞在类风湿性关节炎和系统性红斑狼疮中的活化特点

探讨Th1、Th2和Th17型细胞在类风湿性关节炎(RA)和系统性红斑狼疮(SLE)发病机制中的作用。收集37例RA患者、25例SLE患者和34例健康人的抗凝血,应用ELISA检测血清中IFN-γ、IL-10和IL-17的水平。与健康对照组比较,RA和SLE患者血清中IFN-γ的水平均具有统计学意义(P<0.05);SLE患者IL-10水平出现有意义的升高(P<0.05);而RA患者IL-17的升高具有统计学意义(P<0.05)。由此提示Th1、Th2和Th17细胞在自身免疫性疾病中均发挥不同的重要作用。     

Rubella and rheumatoid arthritis: hyaluronic acid and susceptibility of cultured rheumatoid synovial cells to viruses.

Synovial cell lines were established from patients with rheumatoid arthritis (RA) and from normal human embryos. High levels of hyaluronic acid (HA) were produced by some RA cell lines, some of which were partially or completely resistant to infection with Newcastle disease virus (NDV), vesicular stomatitis virus (VSV), and rubella virus (RV). Normal fetal synovial cells lines were susceptible to NDV, VSV, and RV. Infection with virus became possible after treatment of RA cells with hyaluronidase to depolymerize HA, and HA prevented infection of normal synovial cells with VSV. These results provide evidence that HA and not chronic or latent viral infection is responsible for the lack of susceptibility of RA synovial cells to certain viruses.     

Compensatory up-regulation of behavioral disease avoidance in immuno-compromised people with rheumatoid arthritis

Disgust and disease-related cues can activate the immune system. Here, we test whether immuno-suppression is associated with an up-regulation of cognitions and behaviors that assist in disease avoidance. People with rheumatoid arthritis (RA), who have a heightened risk of infection-related morbidity and mortality, were compared to age, gender and demographically matched healthy controls on a range of disease avoidance tasks. People with RA scored higher on reports of behavior likely to control infection, were more accurate in spotting individuals who were sick, and showed disease-specific ethnocentrism, ascribing a greater risk of contracting disease to non-Caucasians, although having no overall propensity for greater racism on the Modern Racism Scale. Contrary to predictions, disgust sensitivity (DS) did not differ between groups, however among people with RA, DS was found to be lower in those taking drugs that can increase infection risk. While more explicit disease avoidance behaviors are clearly up-regulated in people with RA, changes in DS may have a different and perhaps more biological casual basis.     

Synovial fluid leukocyte apoptosis is inhibited in patients with very early rheumatoid arthritis

Synovial leukocyte apoptosis is inhibited in established rheumatoid arthritis (RA). In contrast, high levels of leukocyte apoptosis are seen in self-limiting crystal arthritis. The phase in the development of RA at which the inhibition of leukocyte apoptosis is first apparent, and the relationship between leukocyte apoptosis in early RA and other early arthritides, has not been defined. We measured synovial fluid leukocyte apoptosis in very early arthritis and related this to clinical outcome. Synovial fluid was obtained at presentation from 81 patients with synovitis of < or = 3 months duration. The percentages of apoptotic neutrophils and lymphocytes were assessed on cytospin preparations. Patients were assigned to diagnostic groups after 18 months follow-up. The relationship between leukocyte apoptosis and patient outcome was assessed. Patients with early RA had significantly lower levels of neutrophil apoptosis than patients who developed non-RA persistent arthritis and those with a resolving disease course. Similarly, lymphocyte apoptosis was absent in patients with early RA whereas it was seen in patients with other early arthritides. The inhibition of synovial fluid leukocyte apoptosis in the earliest clinically apparent phase of RA distinguishes this from other early arthritides. The mechanisms for this inhibition may relate to the high levels of anti-apoptotic cytokines found in the early rheumatoid joint (e.g. IL-2, IL-4, IL-15 GMCSF, GCSF). It is likely that this process contributes to an accumulation of leukocytes in the early rheumatoid lesion and is involved in the development of the microenvironment required for persistent RA.     

Rheumatoid peripheral blood phagocytes are primed for activation but have impaired Fc-mediated generation of reactive oxygen species

Significant levels of circulating immune complexes (ICs) containing rheumatoid factors and immunoglobulin G in peripheral blood are a characteristic feature of rheumatoid arthritis (RA). ICs interact through Fcγ receptors (FcγR) to activate phagocytes in numerous inflammatory processes. The high concentration of neutrophils in synovial fluid during active phases of the disease, together with their destructive capacity, pose important questions as to their role in the pathogenesis of RA. Functional defects in RA or control peripheral blood neutrophil FcγRs were examined with a specific FcγR-mediated reactive oxygen species (ROS) assay. Heterologous cross-linking of FcγRIIa and FcγRIIIb on neutrophils resulted in a significantly decreased production of ROS by RA cells compared with controls matched for age and sex. However, expression and homologous ligation of receptors did not differ between these groups. These data suggest that neutrophil priming does occur before emigration into the joint and that blood neutrophils from patients with RA have a functional impairment in cooperative FcγR-mediated ROS generation. This may account for the increased susceptibility to bacterial infection that arises in patients with severe disease.     

Negative association of the chemokine receptor CCR5 d32 polymorphism with systemic inflammatory response, extra-articular symptoms and joint erosion in rheumatoid arthritis

Introduction  

Chemokines and their receptors control immune cell migration during infections as well as in autoimmune responses. A 32 bp deletion in the gene of the chemokine receptor CCR5 confers protection against HIV infection, but has also been reported to decrease susceptibility to rheumatoid arthritis (RA). The influence of this deletion variant on the clinical course of this autoimmune disease was investigated.     

Is IgG galactosylation the relevant factor for pregnancy-induced remission of rheumatoid arthritis?

During pregnancy, most patients with rheumatoid arthritis (RA) experience spontaneous improvement of their disease activity. Among the soluble candidates that have been investigated in search for the most relevant disease-remitting factor are the galactosylation levels of immunoglobulin G (IgG). In RA, a higher percentage of IgG lacking the terminal galactose residues, thought to play a pro-inflammatory role, is found. During pregnancy, however, IgG galactosylation levels increase and correlate with improved disease activity. The question remains whether the increase in IgG galactosylation during pregnancy is a mere epiphenomenon or a true remission-inducing factor.     

Androgens in rheumatoid arthritis: when are they effectors?

Neither hormone receptor genes nor plasma androgens seem significantly altered in female subjects before they became affected by rheumatoid arthritis (RA) and, therefore, do not seem to play a role as risk factors for its development. However, serum testosterone levels are inversely correlated with RA activity and dehydro-epiandrosterone sulfate (DHEAS) plasma levels are inversely correlated with both disease duration and clinical severity in patients already affected by active RA. In particular, gonadal and adrenal androgens (that is, testosterone and DHEAS) are significantly decreased in inflamed synovial tissue/fluids during active disease as a consequence of the inflammatory reaction, which supports a pro-inflammatory milieu in RA joints. Recently, male gender has been found to be a major predictor of remission in early RA.     

Targeting TNF superfamily members for therapeutic intervention in rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory disease is one of the most serious medical problems, affecting ～1% of all people worldwide, irrespective of race. The disease is autoimmune in nature and characterized by chronic inflammation of the synovial tissues in multiple joints that leads to joint destruction. Although T cells are central players in RA development, B cells are required for full penetrance of disease largely via their production of autoantibodies against Fc domain of IgG rheumatoid factor (RF). Treatment options for RA are limited and if any, are inadequate due to associated side effects. Members of the tumor necrosis factor (TNF) superfamily play important roles in a number of autoimmune diseases, including RA. In this review, we briefly summarize key features of the superfamily, we will consider how the well-characterized members concerned with immune regulation are coordinated and their roles in rheumatoid arthritis.     

Autoantibodies in rheumatoid arthritis and their clinical significance

Autoantibodies are proven useful diagnostic tools for a variety of rheumatic and non-rheumatic autoimmune disorders. However, a highly specific marker autoantibody for rheumatoid arthritis (RA) has not yet been determined. The presence of rheumatoid factors is currently used as a marker for RA. However, rheumatoid factors have modest specificity (~70%) for the disease. In recent years, several newly characterized autoantibodies have become promising candidates as diagnostic indicators for RA. Antikeratin, anticitrullinated peptides, anti-RA33, anti-Sa, and anti-p68 autoantibodies have been shown to have >90% specificity for RA. These autoantibodies are reviewed and the potential role of the autoantibodies in the pathogenesis of RA is briefly discussed.     

The prognostic value of baseline erosions in undifferentiated arthritis

Introduction  

Undifferentiated arthritis (UA) has a variable disease course; 40 to 50% of UA patients remit spontaneously, while 30% develop rheumatoid arthritis (RA). Identifying the UA patients who will develop RA is essential to initiate early disease-modifying anti-rheumatic drug (DMARD) therapy. Although the presence of bone erosions at baseline is predictive for a severe destructive disease course in RA, the prognostic importance of erosive joints for disease outcome in UA is unknown. This study evaluates the predictive value of erosive joints for the disease outcome in UA as measured by RA development and disease persistency.