Th17细胞及IL-23在炎症性肠病中的研究进展

炎症性肠病(IBD)是一种病因和发病机制尚不清楚的发生在胃肠道的慢性非特异性炎症性疾病。大量证据表明先天性和获得性免疫系统的异常均对该疾病起着关键性作用。传统观点认为炎症性肠病与Th1细胞和Th2细胞所介导的免疫应答有关;但最新研究指出,体内Th17细胞以及白细胞介素IL-23的存在,与炎症性肠病的发生息息相关。本文对炎症性肠病中Th17细胞及IL-23的研究进展作一综述。     

炎症性肠病患者外周血辅助性T细胞1和辅助性T细胞17水平及其临床意义

 目的 探讨炎症性肠病（IBD）患者外周血Th1和Th17细胞水平对IBD发病及活动度的意义。方法 收集2011年5月至2012年7月健康对照者40例和IBD患者81例［其中克罗恩病（CD）39例,溃疡性结肠炎（UC）42例］,采集外周血标本。分离外周血单个核细胞,经PMA及伊屋诺霉素联合刺激、培养后,利用流式细胞仪检测Th1和Th17细胞在外周血CD⁺₄T细胞中的百分比,并结合临床资料分析其临床意义。结果 （1）CD组及UC组Th1细胞百分比［(38.32±16.18)%和(34.23±11.60)%］均明显高于健康对照组［(24.58±10.02)%］（P值均<0.01）,而CD组及UC组的差异无统计学意义;CD及UC缓解期患者的Th1细胞百分比均低于活动期患者［(26.50±9.24)%比(48.46±13.83)%,P<0.01;(30.05±7.41)%比(37.68±13.35)%,P<0.05］。（2）CD组及UC组Th17细胞百分比［(2.51±1.59)%和(4.15±2.75)%］均高于健康对照组［(1.44±0.73)%］（P值均<0.01）,且UC组这一比例高于CD组（P<0.01）;CD及UC活动期患者的Th17细胞百分比明显高于缓解期患者［(3.39±1.56)%比(1.48±0.81)%,(5.77±2.77)%比(2.18±0.59)%,P值均<0.01］。（3）UC组外周血Th17/Th1比值（0.14±0.11）高于CD组（0.08±0.06）和健康对照组（0.07±0.06）,P值均<0.01。结论 IBD患者外周血中Th1、Th17细胞占CD⁺₄T细胞比例较健康人群明显升高,且与IBD活动度密切相关。Th1和Th17细胞在IBD发病中可能具有重要作用。     

Role of cytokines in inflammatory bowel disease

Inflammatory bowel disease （IBD）, which includes Crohn’s disease （CD） and ulcerative colitis （UC）, rep- resents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with a relapsing and remitting clinical course. Mucosal mac- rophages play an important role in the mucosal im- mune system, and an increase in the number of newly recruited monocytes and activated macrophages has been noted in the inflamed gut of patients with IBD. Activated macrophages are thought to be major con- tributors to the production of inflammatory cytokines in the gut, and imbalance of cytokines is contributing to the pathogenesis of IBD. The intestinal inflammation in IBD is controlled by a complex interplay of innate and adaptive immune mechanisms. Cytokines play a key role in IBD that determine T cell differentiation of Th1, Th2, T regulatory and newly described Th17 cells. Cytokines levels in time and space orchestrate the development, recurrence and exacerbation of the inflammatory process in IBD. Therefore, several cyto- kine therapies have been developed and tested for the treatment of IBD patients.     

白介素-1 7在溃疡性结肠炎表达的研究

目的研究白介素-17(IL-17)在溃疡性结肠炎(UC)的表达和分泌及与疾病活动性的关系.方法用ELISA法测定UC患者及正常对照者血清或细胞培养液中,IL-17、IL-6和IL-8的浓度,逆转录聚合酶链反应(RT-PCT)测定IL-17mRNA的表达.结果32例UC患者外周血中IL-17,IL-6和IL-8的浓度与40例正常对照者比较,差异无显著性(P＞0.05),但外周血CD+4T细胞在PMA和抗CD3的刺激下,表达IL17mRNA及分泌IL-17的水平均明显高于对照组[(23.6±5.7)pg/ml和(13.1±3.2)pg/ml,P＜0.01].UC患者病变部位的黏膜固有层CD+4T细胞(LP-CD+4T)与非受累部位的LP-CD+4T细胞比较,它们表达大量的IL-17mRNA并自发分泌大量的IL-17蛋白,且IL-17浓度与该部位的单个核细胞(LPMC)分泌的IL-6,以及患者外周血中的C-反应蛋白,血沉均呈显著正相关.在刺激剂的作用下,病变部位的LP-CD+4T细胞IL-17的分泌进一步增加,且明显高于非受累部位LP-CD+4T细胞的分泌水平.另外,UC病变部位LPMC分泌的IL-6和IL-8的水平均明显高于非受累部位的LPMC,但在培养液中加入抗IL-17单克隆抗体后,LPMC细胞IL-6和IL-8的分泌均明显被抑制.结论UC患者病变部位的LP-CD+4T细胞表达和分泌IL-17明显增加,并与疾病的活动性呈正相关.抗IL-17抗体可明显抑制LMPC产生炎性细胞因子.IL-6和IL-8.结果说明,IL-17在UC肠道的炎症病理中起重要作用;阻断IL-17的分泌可能是治疗UC的一种有效手段.     

TNF-α在IBD发病机制中的调节

炎症性肠病（inflammatory bowel disease,IBD）是一种病因不明的肠道非特异性炎症性疾病,包括溃疡性结肠炎和克罗恩病,它们有各自的临床特征,内镜表现和组织学可区分;有学者认为它们是同一疾病的两个不同的阶段。在免疫应答中,TNF-α（TNF核心家族成员之一）作为细胞增殖和凋亡的主要促炎因子,在IBD的发病机制中起重要的调节作用。     

The Interleukin-23 / Interleukin-17 axis in intestinal inflammation

Although the precise aetiology of inflammatory bowel disease (IBD) remains unclear, recent discoveries have led to an improved understanding of disease pathogenesis. Whilst these findings have underscored the central role of innate and adaptive immune responses in intestinal inflammation, they have also precipitated a paradigm shift in the key cytokine pathways that drive disease. The prevailing dogma that IBD was mediated by interleukin (IL)-12-driven T-helper (Th)1 CD4 T cell responses towards the bacterial flora has been largely dispelled by findings that the closely related cytokine IL-23 appears to be the key mediator of intestinal inflammation. IL-23 is associated with a novel subset of IL-17-secreting CD4 T cells termed Th17 cells and rodent studies have implicated the IL-23/IL-17 axis in autoimmune inflammation. Genome-wide association studies in IBD patients have confirmed the predominant role of the IL-23 pathway, indicating that this could represent an important future therapeutic target.     

Th17/Treg失衡与炎症性肠病的关系

炎症性肠病(inflammatory bowel disease.IBD)的病因和发病机制尚未完全明确,肠道黏膜免疫系统异常反应所导致的炎症过程在发病中起重要作用.辅助性T细胞17(T helper 17 cells,Th17)可介导慢性炎症和自身免疫性疾病的发生,调节性T细胞(regulatory T cell,Treg)有抑制自身免疫的功能,二者存在相互转化的关系.有研究表明Th17/Treg转化平衡是维持肠道免疫稳态的重要因素,这可能是导致人类IBD的原因之一.最近研究表明TGF-β,IL-6和维甲酸(retinoic acid,RA)可能是调控二者平衡关系的重要因素.肠道菌群(intestinal flora)与IBD的发生发展关系密切,益生菌(probiotics)对IBD的治疗作用成为研究的热点.深化对Th17/Treg转化调控关系的研究是当前重要的研究课题.     

Th17细胞的生物学特性及其在寄生虫感染中的作用

辅助性T细胞传统上分为Th1型和Th2型.近年研究者发现了一种新的CD4+T细胞亚群,可以产生白细胞介素17(IL-17),被称为Th17细胞.Th17细胞在炎症反应中发挥着重要的调节作用,它的产物IL-17等与原虫、吸虫、绦虫等寄生虫感染有联系.该文就Th17细胞亚群及其产物在寄生虫感染中的作用作一简要综述.     

Interleukin and interleukin receptor gene polymorphisms in inflammatory bowel diseases susceptibility

Inflammatory bowel disease(IBD),which includes Crohn’s disease(CD)and ulcerative colitis(UC),represents a group of chronic inflammatory disorders caused by dysregulated immune responses in genetically predisposed individuals.Genetic markers are associated with disease phenotype and long-term evolution,but their value in everyday clinical practice is limited at the moment.IBD has a clear immunological background and interleukins play key role in the process.Almost130 original papers were revised including meta-analysis.It is clear these data are very important for understanding the base of the disease,especially in terms of clinical utility and validity,but text often do not available for the doctors use these in the clinical practice nowadays.We conducted a systematic review of the current literature on interleukin and interleukin receptor gene polymorphisms associated with IBD,performing an electronic search of PubMed Database from publications of the last 10 years,and used the following medical subject heading terms and/or text words:IBD,CD,UC,interleukins and polymorphisms.     

Dysregulation of mucosal immune response in pathogenesis of inflammatory bowel disease

Inflammatory bowel disease(IBD)includes Crohn’s disease and ulcerative colitis.The exact etiology and pathology of IBD remain unknown.Available evidence suggests that an abnormal immune response against the microorganisms in the intestine is responsible for the disease in genetically susceptible individuals.Dysregulation of immune response in the intestine plays a critical role in the pathogenesis of IBD,involving a wide range of molecules including cytokines.On the other hand,besides T helper(Th)1 and Th2 cell immune responses,other subsets of T cells,namely Th17 and regulatory T cells,are likely associated with disease progression.Studying the interactions between various constituents of the innate and adaptive immune systems will certainly open new horizons of the knowledge about the immunologic mechanisms in IBD.     

Common immunologic mechanisms in inflammatory bowel disease and spondylarthropathies

Spondyloarthropathies （SPA） are commonly observed extra-intestinal manifestations of both Crohn＇s disease （CD） and ulcerative colitis （UC）, the two major forms of inflammatory bowel diseases （[BD）. However, the immunological link between these two clinical entities is still poorly understood. Several lines of evidence indicate that SpA may originate from the relocation to the joints of the immune process primarily induced in the gut. The transfer of the intestinal inflammatory process into the joints implicates that immune cells activated in the gut-draining lymph nodes can localize, at a certain point of the intestinal disease, either into the gut or into the joints. This is indicated by the overlapping expression of adhesion molecules observed on the surface of intestinal and synovial endothelial cells during inflammation. Moreover bacterial antigens and HLA-B27 expression may be implicated in the reactivation of T cells at the articular level. Finally, accumulating evidence indicates that a T helper 17 cell-mediated immune response may contribute to IBD and IBD-related SpA with a crucial role played by tumor necrosis factor-α in CD and to a lesser extent in UC.     

Th17 immune response in IBD: A new pathogenic mechanism

Although traditionally associated with exaggerated Th1 or Th2 cell response, the gut inflammation occurring in patients with IBD is also characterized by production of cytokines made by a distinct lineage of T helper cells, termed Th17 cells. The discovery that this new inflammatory T-cell subset drives immune-mediated pathology and that the antigen-presenting cell-derived IL-23 is necessary for amplifying Th17 cell-associated inflammation has contributed to elucidate new pathways of intestinal tissue damage as well as to open new avenues for development of therapeutic strategies in IBD.In this review, we discuss the available data regarding the involvement of Th17 cells and their interplay with other mucosal cell types in the modulation of intestinal tissue inflammation.     

白细胞介素33在IBD炎症进展和黏膜愈合中的作用

炎症性肠病(IBD)主要包括溃疡性结肠炎(UC)和克罗恩病(CD),近年其发病呈上升趋势。IBD的发病机制尚不明确,研究表明免疫炎症反应起重要作用。白细胞介素33(IL-33)是新近发现的炎症因子,越来越多证据表明其参与IBD发病。本文就IL-33在IBD炎症进展和黏膜愈合中的作用作一综述。     

Careful patient selection may improve response rates to infliximab in inflammatory bowel disease

BACKGROUND AND AIM: The use of infliximab in the treatment of Crohn's disease (CD) is acceptable and appears to be effective in ulcerative colitis (UC). Careful patient selection, resulting in infliximab only for truly refractory inflammatory bowel disease (IBD), may improve its efficacy. The present study aimed to determine if careful patient selection improved infliximab efficacy in IBD. Methods: CD or UC/IBD unclassified patients (Montreal classification) were considered for infliximab treatment only after failure of disease control with conventional therapies and confirmation of active disease. Patients with purely luminal IBD received a single infliximab dose. Patients with fistulizing disease (with or without luminal disease) received infliximab at 0, 2 and 6 weeks. Changes to Harvey Bradshaw (HBI) for inflammatory CD and Colitis Activity Index (CAI) for UC/IBDU were used to determine the response and remission rates. In fistulizing CD, a remission was sustained cessation of drainage and resolution of the fistula. Response was correlated to inflammatory marker levels. RESULTS: Seventy IBD patients were treated. In CD, 85.2% (46/54) had active luminal and 40.7% (22/54) had fistulizing disease. In luminal CD, at 8 weeks a single infliximab dose induced remission in 75% (24/32) of patients compared to 92.9% (13/14) after infliximab at 0, 2 and 6 weeks. Fistulizing disease responded in 77.2% (17/22) and remitted in 50% (11/22) of patients at 8 weeks. In UC/IBDU, 75% (12/16) responded and 43.8% (7/16) of patients were in remission at 8 weeks. CONCLUSION: Careful patient selection may improve infliximab's efficacy and clinical remission appears greater after induction with three infliximab doses in CD. Clinical efficacy is suggested for UC/IBDU.     

Inflammatory bowel disease: epidemiology, pathogenesis, and therapeutic opportunities

Ulcerative colitis (UC) and Crohn's disease (CD), the primary constituents of inflammatory bowel disease (IBD), are precipitated by a complex interaction of environmental, genetic, and immunoregulatory factors. Higher rates of IBD are seen in northern, industrialized countries, with greater prevalence among Caucasians and Ashkenazic Jews. Racial gaps are closing, indicating that environmental factors may play a role. IBD is multigenic, with the most clearly established genetic link between certain NOD2 variants and CD. Regardless of the underlying genetic predisposition, a growing body of data implicates a dysfunctional mucosal immune response to commensal bacteria in the pathogenesis of IBD, especially CD. Possible triggers include a chronic inflammatory response precipitated by infection with a particular pathogen or virus or a defective mucosal barrier. The characteristic inflammatory response begins with an infiltration of neutrophils and macrophages, which then release chemokines and cytokines. These in turn exacerbate the dysfunctional immune response and activate either TH1 or TH2 cells in the gut mucosa, respectively associated with CD and, less conclusively, with UC. Elucidation of immunological and genetic factors indicate multiple points at which the inflammatory cascade may be interrupted, yielding the possibility of precise, targeted therapies for IBD.     

Role of the novel Th17 cytokine IL-17F in inflammatory bowel disease (IBD): upregulated colonic IL-17F expression in active Crohn's disease and analysis of the IL17F p.His161Arg polymorphism in IBD

BACKGROUND: Interleukin (IL)-17F, produced in IL-23R-expressing Th17 cells, is a novel member of the IL-17 cytokine family. Given the association of IL23R with inflammatory bowel disease (IBD), we characterized the role of IL-17F in IBD including its intestinal gene expression and the effect of the IL17F p.His161Arg polymorphism on disease susceptibility and phenotype of Crohn's disease (CD) and ulcerative colitis (UC). In addition, we analyzed the IL17F p.His161Arg polymorphism for potential epistasis with IL23R and NOD2/CARD15 variants. METHODS: Intestinal IL-17F mRNA expression was measured by quantitative polymerase chain reaction (PCR). Genomic DNA from 1682 individuals (CD: n = 499; UC: n = 216; controls: n = 967) was analyzed for the presence of the IL17F p.His161Arg polymorphism, the 3 NOD2 variants, p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008, and 10 CD-associated IL23R variants. RESULTS: Intestinal IL-17F mRNA expression was 4.4-fold increased in inflamed colonic lesions compared to uninflamed biopsies in CD (P = 0.016) but not in UC. However, the mean intestinal IL-17F mRNA expression was higher in UC than in CD (P < 0.0001). The IL17F p.His161Arg substitution was observed with similar frequencies in IBD patients and controls and was not associated with a certain disease phenotype, but weakly associated with a low body mass index (BMI; P = 0.009) and an earlier age of disease onset (P = 0.039) in UC. There was no evidence for epistasis between the IL17F p.His161Arg polymorphism and IBD-associated single nucleotide polymorphisms within the IL23R gene. CONCLUSIONS: Intestinal IL17F gene expression is increased in active CD. The IL17F p.His161Arg polymorphism is not associated with IBD susceptibility and has no epistatic interaction with CD-associated IL23R variants.     

Etiopathogenesis of inflammatory bowel diseases

Theories explaining the etiopathogenesis of inflammatory bowel disease (IBD) have been proposed ever since Crohn's disease (CD) and ulcerative colitis (UC) were recognized as the two major forms of the disease. Although the exact cause(s) and mechanisms of tissue damage in CD and UC have yet to be completely understood, enough progress has occurred to accept the following hypothesis as valid: IBD is an inappropriate immune response that occurs in genetically susceptible individuals as the result of a complex interaction among environmental factors, microbial factors, and the intestinal immune system. Among an almost endless list of environmental factors, smoking has been identified as a risk factor for CD and a protective factor for UC. Among microbial factors, no convincing evidence indicates that classical infectious agents cause IBD, while mounting evidence points to an abnormal immune response against the normal enteric flora as being of central importance. Gut inflammation is mediated by cells of the innate as well as adaptive immune systems, with the additional contribution of non-immune cells, such as epithelial, mesenchymal and endothelial cells, and platelets.