白细胞介素-23/白细胞介素-17轴与自身免疫性皮肤病的研究进展

白细胞介素（IL）-23/IL-17轴是近年来新发现的炎性通路,主要依靠IL-23介导Th17效应细胞,产生IL-17等细胞因子,引起炎性反应及异常免疫,参与多种炎症及自身免疫性疾病.随着医学研究的不断进步,人们对IL-23/IL-17轴及其相关细胞、细胞因子,如Th17细胞、IL-23及IL-17等有了更加清晰的认识,并对其作用及机制有了进一步的了解.在越来越多的自身免疫性皮肤病中发现了此轴的参与.重点阐述了此轴在4种常见结缔组织病、寻常型天疱疮及坏疽性脓皮病中发挥的不同作用,针对此轴的治疗可能为这些自身免疫性皮肤病提供新的治疗靶向.     

Th17细胞在皮肤病的研究进展

Th17细胞不同于Th1、Th2细胞.它由记忆CD4+T细胞、初始T细胞等在IL-6和转化生长因子β、IL-1β或IL-23的作用下分化而来的.成熟的Th17细胞分泌IL-17、IL-22等多种细胞因子,在自身免疫疾病、宿主防御、炎症、肿瘤、移植物排斥等多种病理过程中起着重要的作用.概述Th17细胞的分化、相关细胞因子,以及在皮肤病发病机制中的作用.

Abstract：

Th17 cells are different from Th1 and Th2 cells. They are differentiated from memory CD4+T cells and naive T cells induced by interleukin (IL)-6, transforming growth factor (TGF) 3, IL-1β or IL-23.Mature Th17 cells can secrete many cytokines, such as IL-17, IL-22, etc, and play a crucial role in the pathological process of autoimmune diseases, host defense, inflammatory diseases, tumors and graft-versus-host diseases. This review presents the differentiation and related cytokines of Th17 cells as well as their roles in the pathogenesis of skin diseases.     

IL-17 and IL-17R: an auspicious therapeutic target for psoriatic disease

The continuous discovery of new T cell subpopulations in human autoimmune diseases is making the immunopathological network more complex. Th17 cells are one such newly identified subset of T cells, characterized by the production of signature cytokine IL-17. In last few years, several studies have strongly established the regulatory role of Th17 cells and its signature cytokine IL-17 in autoimmune diseases including psoriasis, psoriatic arthritis, rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus and multiple sclerosis. Psoriasis and PsA are immune mediated hyperproliferative diseases, affecting skin and joint respectively. Before the discovery of Th17 cells, psoriasis and psoriatic diseases were thought to be chiefly Th1 mediated diseases; later on IL-17 knockout animal studies as well as human experimental data indicate the crucial role of Th17 cells and its signature cytokine IL-17 in the pathogenesis of these diseases. In vitro human studies have shown the abundance of Th17 cells in the psoriatic plaques. Subsequently our research group has extended this observation in psoriatic arthritis and found the abundance of CD4+IL-17+ T cells in the synovial fluid and majority of these T cells are of memory phenotype (CD4RO+CD45RA-CD11a+). In addition, we showed the significant presence of functional IL-17 receptor in synovial fibroblast of psoriatic arthritis patients. Considering the strong association of IL-17 and psoriatic disease, IL-17 targeted therapy have shown promises in preclinical and clinical trials. In this review article, we have discussed the pathogenic role of IL-17 in psoriatic disease and summarized the therapeutic efficacy and safety profile of different anti IL-17 therapy as an anti-psoriatic agent.     

SCID MOUSE MODEL OF PSORIASIS: A UNIQUE TOOL FOR DRUG DEVELOPMENT OF AUTOREACTIVE T-CELL AND TH-17 CELL-MEDIATED AUTOIMMUNE DISEASES

In both skin and synovial tissues of psoriatic arthritis (PsA) patients, there are prominent lymphocytic infiltrates localized to the dermal papillae in the skin and the sublining layer stroma in the joint. T-cells, with a predominance of CD4+ lymphocytes, are the most significant lymphocytes in the tissues; in contrast, this ratio is reversed in the epidermis, synovial fluid compartment, and at the enthesis, where CD8+ T-cells are more common. This differential tropism of CD8+ T-cell suggests that the CD8+ T-cells may be driving the immune response in the joint and skin. This is supported by an association with MHC class I. The cytokine network in the psoriatic skin and synovium is dominated by monocyte and T-cell-derived cytokines: IL-1β, IL-2, IL-10, IFN-γ, and TNF-α. In PsA synovium, higher levels of IFN-γ, IL-2, and IL-10 have been detected than in psoriatic skin. An analysis of T-cell receptor beta-chain variable (TCRβV) gene repertoires revealed common expansions in both skin and synovial inflammatory sites, suggesting an important role for cognate T-cell responses in the pathogenesis of PsA and that the inciting antigen may be identical or homologous between the afflicted skin and synovium. Traditionally, T-cells have been classified as T helper 1 (Th1) or Th2 cells by production of defining cytokines, IFN-γ and IL-4, respectively. Recently, a new type of T-cell, Th17, has been linked to autoimmune inflammation. T-helper 17 (Th17) cells are a unique effector CD4+ T-cell subset characterized by the production of interleukin (IL)-17. Murine diseases that were previously considered to be pure Th1-mediated responses have been shown to contain mixed populations of Th1 and Th17 cells. Also, in humans, a critical immunoregulatory role of Th-17 cells in infectious and autoimmune diseases has been identified. It has been postulated that IL-17 may be important in psoriasis. Our initial observations demonstrate that IL-17 and its receptor system are important for PsA also. In in vivo and in vitro studies we have demonstrated that IL-17/IL-17R are enriched in skin, synovial tissue, and synovial fluid of psoriatic arthritis patients and Th17 cells are functionally significant in the pathogenesis of psoriasis and psoriatic arthritis. Here we will share our experience of the SCID mouse model of psoriasis in respect to its use in investigating psoriatic diseases and development of immune-based drugs for psoriasis, psoriatic arthritis, and other autoimmune diseases.     

IL-23／Th17细胞／IL-17通路在皮肤科的研究进展

IL-23是-个由IL-23p19和IL-12p40组成的异二聚体细胞因子,属IL-12细胞因子家族成员,其能够增加已分化的Thl7细胞的数量,保持Thl7细胞所产生的IL-17水平并维持Thl7细胞的存活,依赖IL-23的信号途径在Thl7细胞致病活性中起到重要的作用。目前发现,IL-23/Th17细胞,IL-17通路的紊乱与多种皮肤病的发病相关,针对该通路的特异性治疗可能会带来新的治疗前景。     

Psoriasis vulgaris lesions contain discrete populations of Th1 and Th17 T cells

The importance of T helper 17 (Th17) cells in inflammation and autoimmunity is now being appreciated. We analyzed psoriasis skin lesions and peripheral blood for the presence of IL-17-producing T cells. We localized Th17 cells predominantly to the dermis of psoriasis skin lesions, confirmed that IL-17 mRNA increased with disease activity, and demonstrated that IL-17 mRNA expression normalized with cyclosporine therapy. IL-22 mRNA expression mirrored IL-17 and both were downregulated in parallel with keratin 16. Th17 cells are a discrete population, separate from Th1 cells (which are also in psoriasis lesions), and Th2 cells. Our findings suggest that psoriasis is a mixed Th1 and Th17 inflammatory environment. Th17 cells may be proximal regulators of psoriatic skin inflammation, and warrant further attention as therapeutic targets.     

T helper type 17 in psoriasis: From basic immunology to clinical practice

Psoriasis is a chronic inflammatory disease mediated by a complex interplay between immune system and keratinocytes. Initially considered as a keratinocyte proliferation/differentiation disorder, an immune dysregulation was confirmed after the successful treatment of psoriasis with cyclosporine. The ying–yang theory, or T helper type 1 (Th1)/Th2 concept, was then introduced to explain the rarity of atopic dermatitis in patients with psoriasis and the aggravation of psoriasis after interferon-γ treatment. However, recent advances have revised the Th1/Th2 paradigm after the discovery of a novel subset of T cells, called Th17 cells. Th17 cells produce interleukin (IL)-17 and IL-22, and have other important downstream proinflammatory effects on skin, leading to clinical and pathological features typical of psoriasis. Nowadays, emerging evidence suggests integrative and complicated inflammatory circuits among Th1 and Th17 cells and keratinocytes in the pathogenesis of psoriasis, with Th17 cells playing a central role. Herein, we review the biology of Th17 cells as well as the reciprocal interplay between Th17 and regulatory T cells in psoriasis. Integration of the IL-23/Th17 axis into a revised concept of psoriasis has already been translated into novel therapeutic strategies. Studies investigating the effect and molecular mechanism of conventional and biological therapy for psoriasis on the IL-23/Th17 pathway were also discussed.     

Th17细胞与特应性皮炎

Th17细胞是一种新发现的辅助性T细胞亚型,在自身免疫性疾病、宿主防御反应和变态反应性疾病中发挥作用.特应性皮炎患者急性皮损中IL-17表达显著增高,其皮肤树突细胞通过表达大量IL-23诱导Th17细胞分化.Th17细胞可能通过增强Th2记忆细胞功能、促进角质形成细胞免疫活性,诱导转化生长因子-β1、IL-11、IL-6等炎症因子表达,从而参与特应性皮炎炎症反应和组织重塑等病理生理过程.     

Vitamin D analog calcipotriol suppresses the Th17 cytokine-induced proinflammatory S100 "alarmins" psoriasin (S100A7) and koebnerisin (S100A15) in psoriasis

The antimicrobial peptides (AMP) psoriasin (S100A7) and koebnerisin (S100A15) are differently induced in psoriatic skin. They act synergistically as chemoattractants and "alarmins" to amplify inflammation in psoriasis. Th17 cytokines are key players in psoriasis pathogenesis and vitamin D analogs feature anti-psoriatic effects; both of these activities could be mediated through epidermal AMP regulation. We show that supernatants of cultured psoriatic T cells induce and release psoriasin and koebnerisin from keratinocytes and the Th17 cytokines IL-17A, tumor necrosis factor-α, and IL-22 differently regulate psoriasin and koebnerisin reflecting their distinct expression pattern in normal and psoriatic skin. IL-17A is the principal inducer of both S100 and their expression is further amplified by cooperating Th17 cytokines in the micromilieu of psoriatic skin. Increased extracellular psoriasin and koebnerisin also synergize as "alarmins" to prime epidermal keratinocytes for production of immunotropic cytokines that further amplify the inflammatory response. Treatment of psoriatic plaques with the vitamin D analog calcipotriol interferes with the S100-mediated positive feedback loop by suppressing the increased production of psoriasin and koebnerisin in psoriatic skin and their Th17-mediated regulation in epidermal keratinocytes. Thus, targeting the S100-amplification loop could be a beneficial anti-inflammatory approach in psoriasis and other inflammatory skin diseases.     

The interaction between Langerhans cells and CD4+ T cells.

The human skin is increasingly exposed to haptens and environmental protein antigens. Because Langerhans cells represent the outermost network of MHC class II+ antigen presenting cells in mammalians, we investigated their interaction with CD4+ T cells. Hapten-modified Langerhans cells induced proliferation and IL-2 production in naive resting CD4+ T cells. T cells activated in this manner and subsequently cultured with IL-2 mediated contact sensitivity in vivo and produced IL-2 but no IL-4 upon restimulation in vitro. Thus they corresponded to Th1 cells. Repeated stimulation with Langerhans cells induced a modulation of the lymphokine pattern: IL-2- and IL-4-producing Th0-like cells were identified after 3 to 4 rounds of restimulation; after > 5 rounds, Th2-like cells with an IL-4+IL-2- pattern and the capacity for inducing IgE synthesis in B cells was identified. Th2 cells were also recently found to mediate inflammatory tissue lesions containing a cellular infiltrate. This demonstrates that Langerhans cells may activate resting CD4+ T cells, Th1-, Th0- and Th2-like cells. It further shows that Langerhans cells may promote the differentiation of postthymic CD4+ T cells into subsets with distinct immune functions: Th1 cells which have the potential to mediate inflammatory reactions such as allergic contact sensitivity and Th2 cells which may be responsible for abnormalities associated with atopic dermatitis, such as elevated IgE and inflammatory skin lesions containing a cellular infiltrate.     

Th17 cells: a new therapeutic target in inflammatory dermatoses

Th17 cells, named for their secretion of interleukin-17 (IL-17), are a new class of T-cells involved in a wide range of cutaneous autoimmune and inflammatory conditions. An overactive Th17 cell response in the skin can produce damaging results. There appears to be a partial role for the Th17 axis in the pathogenesis of a range of dermatological diseases including allergic contact dermatitis, atopic dermatitis, psoriasis, and scleroderma. Immunologists have also discovered a unique association between Th17 cells and cutaneous T-cell lymphoma. The Th17 branch has been linked to a number of additional systemic inflammatory diseases with significant cutaneous pathology such as systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, and Behcet's disease. Newly developed treatment modalities for neutralizing the Th17 branch of the immune system are proving to be valuable additions to the current therapeutic armamentarium.     

特应性皮炎与Th17的研究进展

特应性皮炎是一种慢性复发性、炎症性皮肤疾病,病因复杂,涉及环境、基因及免疫之间的相互作用,其中免疫因素为特应性皮炎发病的重要原因之一。Th17作为一个不同于Th1和2的CD4＋T细胞亚群,已经证实,在特应性皮炎发生发展中起重要的作用。Th17通过分泌白介素-17、21、22等细胞因子诱发炎症反应及免疫反应,参与特应性皮炎发病的免疫学机制。通过物理治疗、药物治疗等手段,可以靶向抑制Th17及相关细胞因子,对治疗特应性皮炎有一定疗效。     

Th17细胞相关因子与寻常性进行期银屑病的相关性研究

目的探讨Th17细胞相关因子白细胞介素(IL)-17A、IL-17F、IL-21、IL-22与寻常性进行期银屑病发病的相关性。方法通过实时定量反转录聚合酶链式反应(RT-PCR)分别检测30例患者和20名正常人外周血单个核细胞(PBMC)、12例患者皮损、12名正常皮肤组织中上述4种细胞因子的mRNA表达水平。结果患者组PBMC中IL-17A、IL-17F、IL-21和IL-22的mRNA表达水平较正常组显著升高(P均0.05),患者组皮损中4种细胞因子的mRNA表达明显高于正常组(P均0.05)。结论 Th17细胞因子IL-17A、IL-17F、IL-21和IL-22的mRNA水平在患者组PBMC及皮肤组织中明显升高,提示Th17细胞因子可能与寻常性银屑病的发病有一定相关性。     

T细胞亚群和白细胞介素36在系统性红斑狼疮发病机制中的研究进展

在不同的细胞因子环境下,原始T细胞分化生成的Th1、Th2、Th17及Treg等细胞构成的细胞亚群及其细胞因子在系统性红斑狼疮等自身免疫性疾病的发病中发挥重要作用.白细胞介素36包括白细胞介素36α、363和36 γ,其免疫调节及免疫激活作用较传统白细胞介素1家族成员更强,通过激活丝裂原活化蛋白激酶和核因子κB,参与自身免疫性疾病的生理病理过程.白细胞介素36对T细胞分化的研究能进一步阐明系统性红斑狼疮的发病机制,为系统性红斑狼疮的治疗策略提供思路.     

白介素17与自身免疫性皮肤病

白介素17是由Th17细胞分泌的炎症细胞因子,在机体炎症及免疫性疾病中发挥重要作用.皮肤自身免疫性疾病的发病机制尚不清楚.IL-17的炎性和免疫性双重特征,有望在皮肤自身免疫性疾病的研究中取得突破.进一步研究IL-17在皮肤自身免疫性疾病中的作用,探讨其发病机制,可有效寻找新的药物作用靶点和新的治疗方法.     

Development and characterization of a human Th17-driven ex vivo skin inflammation model

Skin models mimicking features of psoriasis-related inflammation are needed to support the development of new drugs in dermatology. Reconstructed skin models lack tissue complexity, including a fully competent skin barrier, and presence and/or diversity of immune cells. Here, we describe InflammaSkin®, a novel human Th17-driven ex vivo skin inflammation model. In this model, skin-resident T cells are in situ activated by intradermal injection of anti-CD3 and anti-CD28 antibodies and Th17 cell polarization is sustained by culture in a chemically defined medium supplemented with IL-1β, IL-23 and TGF-β for seven days. The acquired Th17 signature is demonstrated by the sustained secretion of IL-17A, IL-17AF, IL-17F, IL-22, IFN-γ, and to some degree IL-15 and TNF-α observed in the activated ex vivo skin inflammation model compared with the non-activated skin model control. Furthermore, expression of S100A7 and Keratin-16 by keratinocytes and loss of epidermal structure integrity occur subsequently to in situ Th17cell activation, demonstrating cellular crosstalk between Th17 cells and keratinocytes. Finally, we demonstrate the use of this model to investigate the modulation of the IL-23/IL-17 immune axis by topically applied anti-inflammatory compounds. Taken together, we show that by in situ activation of skin-resident Th17 cells, the InflammaSkin® model reproduces aspects of inflammatory responses observed in psoriatic lesions and could be used as a translational tool to assess efficacy of test compounds.     

Role of IL-17 and IL-22 in autoimmunity and cancer

The dysregulation of inflammatory cytokines can cause a variety of diseases, such as autoimmunity and cancer. Since their identification in 2005, Th17 cells and its signature cytokine IL-17, have been implicated in the pathogenesis of autoimmune diseases such as psoriasis and rheumatoid arthritis (RA), and inflammatory associated cancers such as colorectal carcinoma (CRC). Recently, IL-22 a Th17 related cytokine has been shown to be pathogenic in psoriasis and RA. In this review, we will summarize the biological functions of IL-17 and IL-22, their role in autoimmune diseases and briefly review results from clinical trials targeting IL-17 or its receptor for the treatment of autoimmune diseases. Next, we will discuss pre-clinical and clinical data supporting the rationale of targeting other cytokines implicated in the Th17/IL-17 pathway, such as IL-22 and IL-23. Finally, we discuss the role of IL-17, and in particularly IL-22 in tumour immunity and possible therapeutic interventions.     

寻常性银屑病患者外周血和皮损中Th17细胞及相关因子的表达

目的 探讨寻常性银屑病患者外周血和皮损中Th17细胞及相关因子IL-17、IL-22表达,分析其与疾病严重程度及病程的相关性。方法 抽取44例寻常性银屑病患者和28例正常人对照者外周血,用三色法流式细胞仪检测外周血Th17细胞,ELISA法检测血清中IL-17、IL-22表达。取20例寻常性银屑病患者皮损和8例正常人对照者皮肤,用量子点免疫荧光双标法检测Th17细胞表达。结果 寻常性银屑病患者外周血Th17细胞百分比（4.71% ± 2.55%）高于正常人对照组（0.55% ± 0.39%）,两组差异有统计学意义（P < 0.01）。银屑病患者Th17细胞与银屑病病情严重度评分（PASI）呈显著正相关（r = 0.53,P < 0.01）,但与病程无相关性（r = 0.09,P > 0.05）。银屑病患者血清中IL-17（24.02 ± 12.31 ng/L）、IL-22（18.32 ± 8.14 ng/L）表达均高于正常人对照组（IL-17为7.16 ± 4.04 ng/L,IL-22为6.52 ± 4.15 ng/L）,差异均有统计学意义（P < 0.01和 < 0.05）。银屑病患者血清IL-17、IL-22表达与PASI呈显著正相关（r = 0.47,P < 0.01;r = 0.53,P < 0.01）,与病程无相关性（r = 0.03,P > 0.05;r = 0.19,P > 0.05）。银屑病患者皮损中可见Th17细胞浸润,主要集中在真皮浅层血管周围;而正常人皮肤中仅有微量CD4+ T细胞表达,未见Th17细胞。 结论 Th17细胞参与银屑病的发病,提示阻断相关因子IL-17、IL-22的药物可成为治疗银屑病的又一新靶点。     

Lesional Th17 cells and regulatory T cells in bullous pemphigoid

Th17 cells play crucial roles in the pathogenesis of autoimmune diseases. We previously reported that Th17 cells are recruited to the lesional skin in pemphigus vulgaris (PV) and pemphigus foliaceus (PF). The aim of this study was to evaluate lesional Th17 cells and Treg cells in bullous pemphigoid (BP). Correlations between these cells and disease severity of BP were also evaluated. Immunohistochemical studies showed that both IL-17+ and Foxp3+ cells were present in higher numbers in BP lesions, compared with control skin. IL-17/CD4 ratio in BP was significantly higher than that in PF. Foxp3/CD4 ratio in BP was significantly less than that in either PV or PF. There were no obvious correlations between these cells and disease severity of BP. This study suggests that, compared with pemphigus, BP shows more Th17 cell-related inflammation and less Treg-related regulation.     

Th17细胞与HIV感染的关系

来源于初始T细胞的Th17细胞是新发现的一类不同于Th1、Th2的CD4+T细胞,其分泌IL-17、IL-6、IL-22和肿瘤坏死因子等细胞因子,在介导慢性炎症反应、自身免疫性疾病等方面发挥着重要作用.研究表明,IL-17在HIV感染中发挥着抗感染作用,同时在抗HIV细胞因子调控网络中,IL-17也起着重要作用.在HIV感染早期,Th17细胞在外周血液及胃肠道中大量减少甚至衰竭,但是Th17能否发挥抗病毒功能还需要更深入探究.研究已证明,病毒首先攻击的靶点细胞是CCR5+CCR6+Th17.Th17作为HIV新的靶向细胞,有望为艾滋病提供新的治疗策略.

Abstract：

Th17 cells that derive from initial T cells are a newly discovered class of CD4+ T cells different from Th1 and Th2 cells. They secrete interleukin (IL)-17, IL-6, IL-22, tumor necrosis factor and other cytokines, and play an important role in mediating chronic inflammation, autoimmune diseases, etc. Recent studies have evidenced that IL-17 posseses a potent anti-HIV activity and exerts a crucial role in anti-HIV cytokine regulatory networks. In early HIV infection, there is a significant reduction or depletion of Th17 cells in peripheral blood and gastrointestinal tract. Nevertheless, further exploration is required to clarify the antiviral function of Th17 cells. Studies have evidenced that the first target of HIV virus attacks is CCR5+CCR6+Th17 cells. As a new target of HIV, Th17 cells are expected to provide new therapeutic strategy for AIDS treatment.