Th17细胞在系统性红斑狼疮免疫炎症反应中的作用机制研究

目的从Th17/Treg、IL-17及RORγt mRNA表达3方面进行研究,探讨Th17细胞在SLE免疫炎症反应中的作用机制。方法研究对象为26例活动期SLE患者、16例非活动期SLE患者和20例正常对照,采用细胞内染色流式细胞术检测Th17/Treg,ELISA法检测IL-17及RT-PCR法检测RORγt mRNA表达,并探讨它们与SLE疾病活动性的关系。结果活动期SLE患者组Th17/Treg、IL-17及RORγt mRNA表达水平显著高于非活动期及正常对照组;非活动期SLE患者组RORγt mRNA表达显著高于正常对照组,但两组间Th17/Treg、IL-17水平无显著差异。SLE患者Th17/Treg、IL-17及RORγt mRNA表达水平均与和SLEDAI呈正相关。结论 SLE患者存在着Th17细胞高表达现象,阻断Th17细胞分化的上游或下游均可能减轻SLE的免疫炎症反应而达到治疗SLE的目的。     

Th17细胞在子痫前期患者外周血表达增加

观察正常妊娠妇女和子痫前期疾病患者外周血CD4+T细胞中Th17细胞和特异性转录因子维A酸相关孤独受体(retinoid-related orphan nuclear receptor,RORγt)的表达和意义。实验组为子痫前期疾病患者25例,正常妊娠妇女20例,未孕妇女20例。采集研究对象外周血,酶联免疫吸附试验(ELISA)检测Th17细胞相关细胞因子IL-17A,IL-6,TNF-α的表达,Ficoll法分离外周血单个核细胞(PBMC),免疫磁珠分选CD4+T淋巴细胞,逆转录-聚合酶联反应(RT-RCR)半定量检测CD4+T细胞中Th17细胞特异性转录因子RORγt的表达,流式细胞术检测CD4+IL-17+T细胞比例。子痫前期患者外周血清中IL-6、IL-17A的含量分别为(31.72±13.34)ng/L、(2.61±1.64)ng/L,高于正常妊娠组水平,差异有显著统计学意义(P<0.01),TNF-α在子二组间的表达分别为(18.00±8.64)ng/L和(11.69±3.68)ng/L,差异有统计学意义(P<0.05);RORγt mRNA在子痫前期组的表达高于正常妊娠组,净光密度值差异有显著统计学差异(P<0.01),CD4+IL-17+T细胞在子痫前期组的表达为(1.83±0.42)%,高于正常妊娠组(0.87±0.26)%,差异有显著统计学意义(P<0.01)。子痫前期患者外周血CD4+T细胞中RORγt mRNA、Th17细胞以及Th17细胞相关细胞因子表达异常,可能在疾病的发病机理中起到重要作用。     

Distinctive features of classic and nonclassic (Th17 derived) human Th1 cells

T helper17 (Th17) lymphocytes represent a third arm of the CD4⁺ T‐cell effector responses, in addition to Th1 and Th2 cells. Th17 cells have been found to exhibit high plasticity because they rapidly shift into the Th1 phenotype in inflammatory sites. In humans, Th1 cells derived from Th17 cells express CD161, whereas classic Th1 cells do not; these Th17‐derived Th1 cells have been termed nonclassic Th1 cells. In this study, we examined similarities and differences between classic and nonclassic human Th1 cells by assessing a panel of T‐cell clones, as well as CD161⁺ or CD161^? CD4⁺ T cells derived ex vivo from the circulation of healthy subjects or the synovial fluid of patients with juvenile idiopathic arthritis. The results show that nonclassic Th1 cells can be identified based on CD161 expression, as well as the consistent expression of retinoic acid orphan receptor C, IL‐17 receptor E, CCR6, and IL‐4‐induced gene 1, which are all virtually absent in classic Th1 cells. The possibility to distinguish these two‐cell subsets by using such a panel of markers may allow the opportunity to better establish the respective pathogenic roles of classic and nonclassic (Th17 derived) Th1 cells in different chronic inflammatory disorders.     

Reasons for rarity of Th17 cells in inflammatory sites of human disorders

T helper 17 (Th17) cells have been reported to be responsible for several chronic inflammatory diseases. However, a peculiar feature of human Th17 cells is that they are very rare in the inflammatory sites in comparison with Th1 cells. The first reason for this rarity is the existence of some self-regulatory mechanisms that limit their expansion. The limited expansion of human Th17 cells is related to the retinoic acid orphan (ROR)C-dependent up-regulation of the interleukin (IL)-4 induced gene 1 (IL4I1), which encodes for a l-phenylalanine oxidase, that has been shown to down-regulate CD3ζ expression in T cells. This results in abnormalities of the molecular pathway which is responsible for the impairment of IL-2 production and therefore for the lack of cell proliferation in response to T-cell receptor (TCR) signalling. IL4I1 up-regulation also associates with the increased expression of Tob1, a member of the Tob/BTG anti-proliferative protein family, which is involved in cell cycle arrest.A second reason for the rarity of human Th17 cells in the inflammatory sites is their rapid shifting into the Th1 phenotype, which is mainly related to the activity of IL-12 and TNF-α. We have named these Th17-derived Th1 cells as non-classic because they differ from classic Th1 cells for the expression of molecules specific for Th17 cells, such as RORC, CD161, CCR6, IL4I1, and IL-17 receptor E. This distinction may be important for defining the respective pathogenic role of Th17, non-classic Th1 and classic Th1 cells in many human inflammatory disorders.     

Th17 cell development: from the cradle to the grave

T cells surviving the clonal selection process emigrate from the thymus to the periphery as immature naive T cells. In the periphery, upon activation under specific cytokine milieus, naive T cells adopt specific effector phenotypes, e.g. T-helper 1 (Th1), Th2, or Th17, and acquire diverse functions to control a myriad of pathogens, tissue injuries, and other immunological insults. Interleukin-23 (IL-23) is one of the key cytokines that shapes the development and function of Th17 cells with characteristic expression of retinoic acid receptor-related orphan receptor γ-t (RORγt), IL-17, IL-22, and granulocyte macrophage colony-stimulating factor (GM-CSF). More recently, emerging data suggest that IL-23 also promotes development of ‘natural Th17’ (nTh17) cells that arise from the thymus, analogous to natural regulatory T cells (nTreg). We are just beginning to understand the unique thymic developmental path of nTh17 cells, which are distinct from antigen-experienced memory Th17 cells. In this review, we explore the differentiation and function of inducible, natural, and memory Th17 subsets, which encompass a broad range of immune functions while maintaining tissue hemostasis, and highlight the participation of IL-23 during the life cycle of Th17 cells.     

Activation of Peripheral Th17 Lymphocytes in Patients with Asthma

A recently identified interleukin (IL)-17-producing T-helper (Th) lymphocyte subset, which comprises Th17 cells producing hallmark cytokines IL-17A, IL-17F and IL-22, is involved in chronic inflammatory diseases. Elevated gene and protein expressions of IL-17 are manifested in allergic asthma. We further characterized the activation of Th17 cells in asthmatic patients. Peripheral blood mononuclear cells (PBMC) were purified from 31 asthmatic patients and 20 sex- and age-matched control subjects. The number of IL-17A secreting cells in peripheral blood was enumerated by enzyme-linked immunosorbent spot assay. Cell surface expression of Th17-related chemokine receptor CCR6, and plasma level of IL-17A, IL-17F and IL-22, and ex vivo production of IL-17A and IL-22 were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. The number of peripheral Th17 lymphocytes, expression of CCR6 on Th cells, and ex vivo IL-23, anti-CD3 and anti-CD28 induced production of IL-22 by PBMC were significantly elevated in asthmatic patients compared with control subjects (all p < 0.01). This clinical study further confirmed increased number of peripheral Th17 lymphocytes and cell surface expression of CCR6 receptors on Th cells in asthmatic patients. Pro-inflammatory cytokine IL-23 can exacerbate disease severity by activating pathogenic Th17 lymphocytes to release downstream inflammatory cytokine IL-22 in asthma.     

Vitamin D reduces the differentiation and expansion of Th17 cells in young asthmatic children

Vitamin D [25(OH)D3] deficiency has been associated with asthma as in many inflammatory and autoimmune pathologies; however, there is still a lack of data about the effects of administration of vitamin D in immune regulation in young asthmatic patients. In this study, we investigated its inhibitory effect on the immune response in young asthmatic patients and the possible mechanisms involved.     

川崎病急性期患者Th17细胞检测及意义

目的:探讨川崎病患者急性期Th17细胞的水平及意义。方法:急性期川崎病(KD)患儿43例,正常同年龄对照41例,采用流式细胞术检测外周血单个核细胞(PBMC)中Th17细胞占CD4+细胞的比例。荧光定量PCR(Real-time-PCR)检测RORγt和IL-23p19mRNA的表达。双抗体夹心酶联免疫吸附法(ELISA)检测血清IL-6水平。结果:急性期KD患儿外周血Th17细胞比例及其特异性转录因子RORγt的mRNA表达分别为:(1.285±0.625)%、(M:5.62,Q:7.16),显著高于同龄对照组(0.584±0.407)%、(M:1.79,Q:2.55),(P0.01)。KD患儿血清IL-6水平显著增高[病人:(M:36.42,Q:129.77)、对照:(M:2.39,Q:1.15)](P0.01),且与Th17细胞比例成正相关(r=0.88,P0.01)。IL-23p19的mRNA表达与正常对照比较无显著差异[病人:(M:2.12,Q:3.05)、对照:(M:1.73,Q:2.79)](P0.05)。结论:急性期川崎病患者Th17细胞数量、血清IL-6水平升高;Th17可能作为急性炎症的启动因素,参与川崎病免疫发病过程。     

Th17细胞及其相关细胞因子在幽门螺杆菌感染中的作用研究

目的 探讨Th17细胞及其相关细胞因子在幽门螺杆菌(H.pylri)感染中的作用.方法 建立幽门螺杆菌感染的小鼠模型,同时设立治疗组与对照组.HE染色评价小鼠胃组织学改变;RT-PCR法检测胃组织IL-17 mRNA、IL-23 mRNA表达水平;ELISA法检测胃组织匀浆上清IL-17、IL-23含量;FCM检测脾脏单细胞悬液中Th17细胞应答情况.结果 与对照组相比,H.pylori感染组小鼠胃组织IL-17、IL-23在mRNA及蛋白水平表达均升高,脾淋巴细胞中Th17细胞比例显著升高;而且H.pylori感染组小鼠IL-17、IL-23 mRNA和蛋白含量以及脾淋巴细胞中Th17细胞比例随感染时间延长而增加;治疗组小鼠IL-17、IL-23表达量及脾淋巴细胞中Th17细胞比率,与治疗前即感染后4周的小鼠相比较均有所下降;感染后不同时期小鼠胃黏膜的炎症程度与IL-17、IL-23的表达量存在正相关.结论 H.pylori感染后可以诱导Th17细胞应答且IL-17、IL-23表达均上调;H.pylori感染后胃炎程度与胃组织1L-17、IL-23含量存在正相关.     

乙肝相关慢加急性肝衰竭患者Th17细胞水平及其临床意义

目的探讨乙肝相关慢加急性肝衰竭（HBV-ACLF）外周血Th17细胞的表达及其与临床转归的关系。方法采用流式细胞术分析外周血中Th17细胞比例,flowcytomix技术检测血清中IL-17的水平,荧光PCR检测HBV-DNA载量,ELISA检测HBeAg的状态,分析Th17细胞及IL-17的表达与HBV病毒及预后的关系。结果与健康对照组及慢乙肝组相比,HBV-ACLF患者Th17细胞及IL-17水平明显升高（P〈0.01）,且Th17细胞与IL-17水平成正相关;进一步分析发现不同病毒复制水平及HBeAg状态的HBV-ACLF患者Th17细胞及IL-17的差异无统计学意义;与预后好转患者相比,预后不佳HBV-ACLF患者Th17细胞及IL-17水平明显增高（P〈0.05）,且IL-17的水平与终末期肝病评分成正相关。结论 Th17细胞可能参与了HBV-ACLF的发病机制,且IL-17的表达越高可能提示患者的预后不佳。     

Development and evolution of RORγt+ cells in a microbe's world

The nuclear hormone receptor retinoid-related orphan receptor γt (RORγt) induces a pro-inflammatory program in lymphoid cells, culminating in the expression of interleukin-6 (IL-6), IL-17, IL-22, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor. During ontogeny, the first type of cells expressing RORγt are lymphoid tissue inducer cells, a type of innate lymphoid cell (ILC) generated in mammalian fetuses to induce the development of lymph nodes and Peyer's patches. After birth, RORγt(+) ILCs and RORγt(+) T cells are involved in the defense of epithelial surfaces against extracellular microbes and play an important role in the intestinal homeostasis with symbiotic microbiota. The development and evolution of RORγt(+) cells is intimately associated with the construction of a stable host-microbe interface.     

TGF‐β indirectly favors the development of human Th17 cells by inhibiting Th1 cells

Human Th17 clones and circulating Th17 cells showed lower susceptibility to the anti‐proliferative effect of TGF‐β than Th1 and Th2 clones or circulating Th1‐oriented T cells, respectively. Accordingly, human Th17 cells exhibited lower expression of clusterin, and higher Bcl‐2 expression and reduced apoptosis in the presence of TGF‐β, in comparison with Th1 cells. Umbilical cord blood naïve CD161⁺CD4⁺ T cells, which contain the precursors of human Th17 cells, differentiated into IL‐17A‐producing cells only in response to IL‐1β plus IL‐23, even in serum‐free cultures. TGF‐β had no effect on constitutive RORγt expression by umbilical cord blood CD161⁺ T cells but it increased the relative proportions of CD161⁺ T cells differentiating into Th17 cells in response to IL‐1β plus IL‐23, whereas under the same conditions it inhibited both T‐bet expression and Th1 development. These data suggest that TGF‐β is not critical for the differentiation of human Th17 cells, but indirectly favors their expansion because Th17 cells are poorly susceptible to its suppressive effects.     

Life, death, and miracles: Th17 cells in the intestine

Th17 cells, a distinct subset of CD4(+) T-helper cells, are commonly associated with chronic inflammatory and autoimmune diseases; however, Th17 cells also possess a variety of beneficial functions as they maintain and defend mucosal barriers against pathogens and promote tissue repair. Furthermore, recent findings indicate that Th17 cells can also acquire immunosuppressive functions that protect against inflammatory and auto-immune diseases. A sentinel population of Th17 cells is localized in the intestine in the absence of pathology and, in response to infection, this population expands in number, and can also modulate its functions. This review discusses the beneficial and pathogenic roles played by Th17 cells in the intestine.     

Transcriptional regulation of Th17 cell differentiation

The paradigm of effector T helper cell differentiation into either Th1 or Th2 lineages has been profoundly shaken by the discovery of T cells that secrete IL-17 and other inflammatory cytokines. This subset, referred to as Th17, is centrally involved in autoimmune disease and is important in host defense at mucosal surfaces. In mouse, a series of cytokines, including IL-6, IL-21, IL-23, and TGF-beta, function sequentially or synergistically to induce the Th17 lineage. Other cytokines, including IL-2, IL-4, IFNgamma, and IL-27, inhibit differentiation of this lineage. Here we review how the nuclear orphan receptor RORgammat functions to coordinate the diverse cytokine-induced signals and thus controls Th17 cell differentiation.