白细胞介素17在类风湿性关节炎中意义的探讨

白细胞介素17（interleukin-17,IL-17）是近年来发现的一种重要的炎症性细胞因子。主要由CD4＋效应T细胞的亚群-辅助性T细胞17（T help cell 17,Th17）、CD8＋T细胞和γδT细胞产生,能调节并促进多种炎性介质的产生,有强大的招募中性粒细胞的作用,在白细胞的迁移、破骨细胞的活化和骨质的吸收等方面发挥重要作用。近年来研究发现,IL-17与多种炎性疾病、感染、肿瘤、过敏、及自身免疫性疾病均有密切关系,尤其在类风湿性关节炎（rheumatoid arthritis,RA）发病的各个环节中起重要作用。本文对IL-17在类风湿性关节炎的发生、发展、诊断及治疗等方面的作用进行综述。     

A regulatory effect of IL-21 on T follicular helper-like cell and B cell in rheumatoid arthritis

Introduction

Interleukin (IL)-21 is a member of type I cytokine family. Recent studies indicate that IL-21 can promote T follicular helper (Tfh) cell differentiation and survival, a specialized T cell subset which provides help for B cell. It can also regulate the activation, proliferation and differentiation of human B cell and immunoglobulin (Ig) production as well as isotype switching of plasma cell. Rheumatoid arthritis (RA) is characterized by auto-antibodies overproduction such as rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody, suggesting a pivotal role of Tfh cell and B cell in the pathogenesis of RA. This study aimed to investigate whether IL-21 had a regulatory effect on Tfh cell and B cell in RA.

Methods

Serum IL-21 concentrations were measured by ELISA. The correlations between serum IL-21 levels and clinical features of RA patients were analyzed by Spearman''s rank test. The percentages of Tfh-like cells, IL-21 receptor (R) expression on Tfh-like cells and B cells in peripheral blood (PB) were analyzed by flow cytometry. Peripheral blood mononuclear cells (PBMC) were stimulated by rIL-21 (100 ng/ml) in the presence or absence of anti-CD40 and/or anti-IgM, and changes of IL-21R, activation-associated surface markers (CD25, CD69 and CD40), the proliferation, apoptosis and differentiation of B cells were analyzed by flow cytometry. Production of IgG and IgM in the culture supernatants was determined by ELISA.

Results

The results showed that the serum IL-21 levels in RA patients were significantly higher than that of healthy controls (HC). IL-21 concentrations were positively correlated with 28-joint count disease activity score (DAS28) and anti-CCP antibody in RA patients with high IL-21 levels. Furthermore, the frequencies of peripheral CXCR5⁺PD-1⁺CD4⁺ Tfh-like cells markedly increased in RA patients and the percentages of Tfh-like cells were positively correlated with DAS28 and anti-CCP antibody levels. Moreover, elevated IL-21 levels were also correlated with the frequencies of Tfh-like cells. IL-21R expression on both Tfh-like cells and B cells were significantly enhanced in RA patients. In cultures vitro, exogenous IL-21 upregulated IL-21R expression and activation-associated surface markers on B cells and promoted more B cell proliferation in RA than in HC. This IL-21-mediated effect could be reversed by IL-21R-specific neutralizing antibody. Importantly, IL-21 promoted more differentiation of B cell into plasmablast and higher levels of IgG and IgM production in RA than in HC.

Conclusions

Increased serum IL-21 levels in RA patients correlate with DAS28, anti-CCP antibody and frequencies of Tfh-like cells. IL-21 supports B cell activation, proliferation and antibody secretion via IL-21R pathway. Thus, IL-21 may be involved in the pathogenesis of RA and antagonizing IL-21 could be a novel strategy for the therapy of RA.     

Circulating cytokine pattern and factors describing rheumatoid arthritis: IL-15 as one of the biomarkers for RA?

The aim of study was to examine relationship among levels of cytokines (IL-6, IL-13, IL-15, TNF-α) and chemokine (IL-8), production of autoantibodies, radiographic progression, and factors describing rheumatoid arthritis (RA). A total of 156 RA patients according to ACR criteria, and 55 control subjects were recruited into study. We observed higher levels of IL-15 within RA patients compared to healthy controls. Correlations among cytokine levels and the measures of rheumatoid factors, anti-CCP, measures of disease activity, and radiographic progression were observed. We conclude that IL-15 level in circulation could serve as one of the biomarkers for RA detection.     

The rheumatoid arthritis-associated autoantigen hnRNP-A2 (RA33) is a major stimulator of autoimmunity in rats with pristane-induced arthritis

A single intradermal injection of the mineral oil pristane in susceptible DA.1F rats induces erosive arthritis closely mimicking rheumatoid arthritis (RA). Pristane-induced arthritis (PIA) is driven by autoreactive T cells but no autoantigen has been identified to date. We therefore analyzed B and T cell responses to autoantigens potentially involved in the pathogenesis of RA, including IgG, citrullinated proteins, stress proteins, glucose-6-phosphate isomerase, and heterogeneous nuclear ribonucleoprotein (hnRNP)-A2 (RA33). IgG and IgM autoantibodies to hnRNP-A2 were detectable in sera of pristane-primed DA.1F rats already 1 wk before disease onset, reached maximum levels during the acute phase, and correlated with arthritis severity. Apart from rheumatoid factor, autoantibodies to other Ags were not observed. CD4(+) lymph node cells isolated 10 days after pristane injection produced IFN-gamma but not IL-4 in response to stimulation with hnRNP-A2, whereas none of the other candidate Ags elicited cytokine secretion. Surprisingly, hnRNP-A2 also stimulated lymph node cells of naive animals to produce inflammatory cytokines in a MyD88-dependent manner. Furthermore, hnRNP-A2 was highly overexpressed in the joints of rats injected with pristane. Overexpression coincided with the appearance of anti-RA33 Abs and preceded the onset of clinical symptoms of PIA by several days. Taken together, these data suggest hnRNP-A2 to be among the primary inducers of autoimmunity in PIA. Therefore, this Ag might play a pivotal role in the pathogenesis of PIA and possibly also human RA.     

Crocin reduces the inflammation response in rheumatoid arthritis

This study is to determine the role and mechanism of crocin in rheumatoid arthritis (RA). Totally 60 Wistar SD rats were randomly divided into control group, RA model group, methotrexate group, crocin high dose, middle dose, and low dose groups. The paw swelling degree, arthritis score, thymus and spleen index, the mRNA and protein levels of iNOS, and the serum content of TNF-α, IL-1β, and IL-6 were evaluated. Crocin treatment significantly alleviated the paw swelling of RA rats. The arthritis score in crocin treatment groups was significantly lower than that in RA model group. Additionally, the thymus index, but not the spleen index, declined remarkably in crocin treatment groups than in RA model group. Besides, crocin administration significantly reduced the iNOS production and the serum content of TNF-α, IL-1β, and IL-6. Crocin may exert potent anti-RA effects through inhibiting cytokine.     

Cytokine, activation marker, and chemokine receptor expression by individual CD4(+) memory T cells in rheumatoid arthritis synovium

IL-10, IL-13, IFN-gamma, tumor necrosis factor (TNF)-alpha, LT-alpha, CD154, and TNF-related activation-induced cytokine (TRANCE) were expressed by 2-20% of rheumatoid arthritis (RA) synovial tissue CD4(+) memory T cells, whereas CD4(+) cells that produced IL-2, IL-4, or IL-6 were not detected. Expression of none of these molecules by individual CD4(+) cells correlated with the exception of TRANCE and IL-10, and TRANCE and TNF-alpha. A correlation between expression of IL-10 and CCR7, LT-alpha and CCR6, IFN-gamma and CCR5, and TRANCE and CXCR4 was also detected.     

Retinoic acid attenuates rheumatoid inflammation in mice

Retinoic acid is the active vitamin A derivative and is well-known to have diverse immunomodulatory actions. In this study, we investigated the impact of all-trans retinoic acid (ATRA), a biologic key metabolite of vitamin A, on the development of arthritis and the pathophysiologic mechanisms by which ATRA might have antiarthritic effects in animal model of rheumatoid arthritis (RA; collagen-induced arthritis [CIA] in DBA/1J mice). We showed that treatment with ATRA markedly suppressed the clinical and histologic signs of arthritis in the CIA mice. It reduced the expression of IL-17 in the arthritic joints. Interestingly, Foxp3(+) regulatory T cells were markedly increased and IL-17-producing CD4(+) T cells (Th17 cells) were decreased in the spleens of ATRA-treated mice. In vitro treatment with ATRA induced the expression of Foxp3 and repressed the IL-17 expression in the CD4(+) T cells in mice. ATRA suppressed the production of total IgG and IgG2a in splenocytes that were stimulated by LPS. It also reduced serum levels of total IgG and IgG2 anti-collagen Abs and germinal center formation in CIA mice. In addition, the ATRA-treated mice showed decreased osteoclast formation in arthritic joints. Moreover, ATRA downregulated the expression of receptor activator of NF-κB ligand, the leading player of osteoclastogenesis, in the CD4(+) T cells and fibroblast-like synoviocytes from patients with RA. Furthermore, ATRA prevented both human monocytes and mice bone marrow-derived monocytes/macrophage cells from differentiating into osteoclasts. These data suggest ATRA might be an effective treatment modality for RA patients.     

Suppression of proteoglycan-induced arthritis by anti-CD20 B Cell depletion therapy is mediated by reduction in autoantibodies and CD4+ T cell reactivity

B cells have been implicated in the pathogenesis of rheumatoid arthritis (RA) since the discovery of RA as an autoimmune disease. There is renewed interest in B cells in RA based on the clinical efficacy of B cell depletion therapy in RA patients. Although, reduced titers of rheumatoid factor and anti-cyclic citrullinated peptide Abs are recorded, the mechanisms that convey clinical improvement are incompletely understood. In the proteoglycan-induced arthritis (PGIA) mouse model of RA, we reported that Ag-specific B cells have two important functions in the development of arthritis. PG-specific B cells are required as autoantibody-producing cells as well as Ag-specific APCs. Herein we report on the effects of anti-CD20 mAb B cell depletion therapy in PGIA. Mice were sensitized to PG and treated with anti-CD20 Ab at a time when PG-specific autoantibodies and T cell activation were evident but before acute arthritis. In mice treated with anti-CD20 mAb, development of arthritis was significantly reduced in comparison to control mAb-treated mice. B cell depletion reduced the PG-specific autoantibody response. Furthermore, there was a significant reduction in the PG-specific CD4(+) T cell recall response as well as significantly fewer PG-specific CD4(+) T cells producing IFN-gamma and IL-17, but not IL-4. The reduction in PG-specific T cells was confirmed by the inability of CD4(+) T cells from B cell-depleted mice to adoptively transfer disease into SCID mice. Overall, B cell depletion during PGIA significantly reduced disease and inhibited both autoreactive B cell and T cell function.     

Targeting Interleukin-6: All the Way to Treat Autoimmune and Inflammatory Diseases

Interleukin (IL)-6, a cytokine featuring redundancy and pleiotropic activity, contributes to host defense against acute environmental stress, while dysregulated persistent IL-6 production has been demonstrated to play a pathological role in various autoimmune and chronic inflammatory diseases. Targeting IL-6 is thus a rational approach to the treatment of these diseases. Indeed, clinical trials of tocilizumab, a humanized anti-IL-6 receptor antibody have verified its efficacy and tolerable safety for patients with rheumatoid arthritis, Castleman''s disease and systemic juvenile idiopathic arthritis, resulting in approval of this innovative biologic for treatment of these diseases. Moreover, a considerable number of case reports and pilot studies of off-label use of tocilizumab point to the beneficial effects of tocilizumab for a variety of other phenotypically different autoimmune and chronic inflammatory diseases. Elucidation of the source of IL-6 and of mechanisms through which IL-6 production is dysregulated can thus be expected to lead to clarification of the pathogenesis of various diseases.     

Anti-interleukin-6 receptor antibody, tocilizumab, for the treatment of autoimmune diseases

Interleukin (IL)-6 is a cytokine with multiple biological activities. It contributes to host defense against pathogens, whereas accelerated production of IL-6 plays a significant pathological role in various diseases. Clinical trials have demonstrated the efficacy of tocilizumab, a humanized anti-IL-6 receptor antibody, for patients with rheumatoid arthritis, Castleman's disease or juvenile idiopathic arthritis, leading to approval of this innovative drug for the treatment of these diseases. Since IL-6 has been demonstrated to play a significant role in the development of various other autoimmune and inflammatory diseases, tocilizumab can be expected to become a novel drug for such diseases as well.     

Differentiation of naive CD4<Superscript>+</Superscript> T cells towards T helper 2 cells is not impaired in rheumatoid arthritis patients

An impaired differentiation of naive CD4+ T cells towards Th2 cells may contribute to the chronic tissue-destructive T-cell activity in rheumatoid arthritis (RA). The differentiation of naive CD4+ T cells into memory Th2 cells by IL-7 in comparison with that by IL-4 was studied in RA patients and in healthy controls. Naive CD4+ T cells from peripheral blood were differentiated by CD3/CD28 costimulation in the absence of or in the presence of IL-7 and/or IL-4. The production of IFN-gamma and IL-4 was measured by ELISA and by single-cell FACS analysis to indicate Th1 and Th2 cell activity. CD3/CD28 costimulation and IL-7 were early inducers of IL-4 production, but primarily stimulated IFN-gamma production. In contrast, in short-term cultures exogenously added IL-4 did not prime for IL-4 production but suppressed IL-7-induced IFN-gamma production. Upon long-term stimulation of naive CD4+ T cells, IFN-gamma production was differentially regulated by IL-7 and IL-4, but IL-4 production was increased by both IL-7 and IL-4. IL-7 and IL-4 additively induced polarization towards a Th2 phenotype. This susceptibility of naive CD4+ T cells to become Th2 cells upon culture with IL-7 and IL-4 was increased in RA patients compared with that in healthy controls. These findings demonstrate that, in RA patients, differentiation of naive CD4+ T cells towards a Th2 phenotype by CD3/CD28 costimulation, IL-7 and IL-4 is not impaired. The perpetuation of arthritogenic T-cell activity in RA therefore seems not to be the result of intrinsic defects of naive CD4+ T cells to develop towards suppressive memory Th2 cells.     

Impact of interleukin-21 in the pathogenesis of primary Sjogren's syndrome: increased serum levels of interleukin-21 and its expression in the labial salivary glands

Introduction

Interleukin (IL)-21 is a cytokine that controls the functional activity of effector T helper cells and the differentiation of Th17 cells, and promotes B-cell differentiation. To test whether IL-21 participates in the pathogenesis of primary Sjögren''s syndrome (SS), serum IL-21 level was measured and IL-21 expression in the labial salivary glands (LSG) was examined.

Methods

Serum IL-21 levels in 40 primary SS, 40 rheumatoid arthritis (RA), and 38 systemic lupus erythematosus (SLE) patients and 20 healthy controls were measured. Serum IL-21 levels of SS patients were assessed for correlations with laboratory data, including anti-nuclear antibody, anti-Ro/La antibodies, globulin, immunoglobulin (Ig) class, and IgG subclass. LSGs from 16 primary SS and 4 controls with sicca symptoms were evaluated for IL-21 and IL-21 receptor (IL-21R) expression by immunohistochemistry. Confocal microscopy was performed to further characterize the IL-21 positive cells.

Results

Primary SS patients had significantly higher serum IL-21 levels than controls, and these increments correlated positively with levels of IgG, IgG1. Serum IgG1 levels correlated with anti-Ro antibody titers. Immunohistochemical analyses showed that lymphocytic foci and the periductal area of the LSGs from SS patients expressed high levels of IL-21 and lower levels of IL-21R, whereas the control LSGs showed minimal expression of both antigens. The more the lymphocyte infiltrated, IL-21expression in LSGs showed a tendency to increase. Confocal microscopic analyses revealed that IL-21 expressing infiltrating lymphocytes in the LSGs of SS patients also expressed CXCR5.

Conclusions

Primary SS is associated with high serum IL-21 levels that correlate positively with serum IgG, especially IgG1, levels. The expression of IL-21 is increased as more lymphocytes infiltrated in LSGs. These observations suggest that IL-21 may play an important role in primary SS pathogenesis.     

Inhibition of IL6 in rheumatoid arthritis and juvenile idiopathic arthritis

A number of clinical trials have been done to investigate the role of interleukin-6 (IL-6) as a potential therapeutic target in rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). Most of the data testing this comes from trials of the humanized anti Il-6 receptor antibody tocilizumab. Results from clinical trials worldwide have been promising so far. Additional study will define the ultimate role of tocilizumab and Il6 inhibitors in the treatment paradigms for RA and JIA.     

Direct stimulation of cytokines (IL-1 beta, TNF-alpha, IL-6, IL-2, IFN-gamma and GM-CSF) in whole blood: II. Application to rheumatoid arthritis and osteoarthritis.

Rheumatoid arthritis (RA) is an immune disease in which the pathological immune reaction is thought to be initiated by the presentation of an (auto) antigen or superantigen by MHC class II positive cells to CD4 T cells. These successive immunological events can be studied by the cytokines produced at the different stages. Cytokine secretion by stimulated cells in autologous diluted whole blood has allowed the study of the immune profile characteristic of rheumatoid arthritis. The pattern of RA patient whole blood cells cultured in autologous blood is characterized by hyperactivity of the mononuclear cells with high secretion of IL-1 beta, TNF-alpha and IL-6 and low production of IFN-gamma, in comparison with the normal (N) and osteoarthrosis (OA) populations. The IL-2 secretion pattern is unique, arising from production followed by consumption. This production-consumption turnover is the most elevated in the RA group. The T cells are indeed activated in rheumatoid arthritis but regulatory events suppress some of their functions. A correlation was found between the inflammatory proteins and mediators of cellular immunity and macrophagic function: IL-1 beta and the sedimentation rate; IL-6 and fibrinogen; TNF-alpha and the number of blood monocytes. The secretion of OA-stimulated whole blood cells was similar to RA for two monokines (overproduction of TNF-alpha and IL-6) and different for IL-1 beta, not different from normal in OA. Stimulated whole blood cell cytokine secretion profile from RA and OA groups, was the same as previously observed in synovial fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ingested (oral) tocilizumab inhibits EAE

BackgroundBlocking the activity of IL-6 can inhibit autoimmune diseases such as rheumatoid arthritis and Crohn’s disease.ObjectiveWe examined whether an antibody against IL-6, tocilizumab (TCZ) (Actemra®), used clinically in rheumatoid arthritis (RA) would have similar anti-inflammatory effects in EAE after oral administration.Design/methodB6 mice were immunized with MOG peptide 35–55 and gavaged with control saline or TCZ during ongoing disease. Splenocytes, CD4⁺ T cells or macrophages/monocyte lineage cells (CD11b⁺) from control fed or TCZ fed mice were adoptively transferred into active MOG peptide 35–55 immunized recipient mice during ongoing disease. Actively fed and recipient mice were examined for disease inhibition, inflammation, and cytokine responses.ResultsIngested (oral) TCZ inhibited ongoing disease and decreased inflammation. Adoptively transferred cells from TCZ fed donors protected against actively induced disease and decreased inflammation. There was a decrease in IL-6 in actively treated spleen, decrease in TNF-α, Th1-like cytokine IL-12 and increase in Th2-like cytokine IL-10 in active fed and adoptively treated recipients.ConclusionsIngested (orally administered) TCZ can inhibit disease, CNS inflammation, decrease pro-inflammatory Th1-like cytokines and increase Th2-like anti-inflammatory cytokines.     

The neuroimmune semaphorin-3A reduces inflammation and progression of experimental autoimmune arthritis

Semaphorin-3A (Sema3A), a member of a large family of conserved proteins originally implicated in axon guidance, is expressed by activated T cells and downmodulates T cell activation in vitro. This study examined the effect and mechanism of action of Sema3A overexpression in a mouse model of collagen-induced arthritis. Prophylactic i.p. administration of plasmid DNA encoding Sema3A markedly reduced the incidence, disease severity, and articular inflammation compared with control plasmid without insert. Treatment of Sema3A reduced anticollagen IgG levels and suppressed collagen-specific proinflammatory cytokine (IFN-γ and IL-17) release, but increased IL-10 concentration in the serum. In line with results in arthritic mice, Sema3A expression is defective in CD4(+) T cells derived from patients with rheumatoid arthritis. In contrast, increased expression of the Sema3A receptor neuropilin-1 (NP-1) is detected in the same cells. The CD4(+)NP-1(+) T cells are a T cell subset involved in the control of the immune responses. They express greater amounts of IL-10 and show suppressive activities on autologous CD4(+) T cells. Sema3A acted directly on CD4(+)NP-1(+) T cells, because it could increase IL-10 production and influence the regulatory function on CD4(+) T cell growth. Therefore, I propose that Sema3A increases the CD4(+)NP-1(+) T cell ability to suppress alloresponses, that its transient expression is altered in rheumatoid inflammation, and that reintroduction of Sema3A is sufficient to attenuate collagen-induced arthritis, supporting its therapeutic potential in the treatment of autoimmune disorders.     

IL-38: A new factor in rheumatoid arthritis

The newly characterized cytokine IL-38 (IL-1F10) belongs to the IL-1 family of cytokines. Previous work has demonstrated that IL-38 inhibited Candida albicans-induced IL-17 production from peripheral blood mononuclear cells. However, it is still unclear whether IL-38 is an inflammatory or an anti-inflammatory cytokine. We generated anti-human IL-38 monoclonal antibodies in order to perform immunohistochemical staining and an enzyme-linked immunosorbent assay. While human recombinant IL-38 protein was not cleaved by recombinant caspase-1, chymase, or PR3 in vitro, overexpression of IL-38 cDNA produced a soluble form of IL-38 protein. Furthermore, immunohistochemical analysis showed that synovial tissues obtained from RA patients strongly expressed IL-38 protein. To investigate the biological role of IL-38, C57BL/6 IL-38 gene-deficient (^?/?) mice were used in an autoantibody-induced rheumatoid arthritis (RA) mouse model. As compared with control mice, IL-38 ^(?/?) mice showed greater disease severity, accompanied by higher IL-1β and IL-6 gene expression in the joints. Therefore, IL-38 acts as an inhibitor of the pathogenesis of autoantibody-induced arthritis in mice and may have a role in the development or progression of RA in humans.     

Induction of IL-10-producing CD4+CD25+ T cells in animal model of collagen-induced arthritis by oral administration of type II collagen

Induction of oral tolerance has long been considered a promising approach to the treatment of chronic autoimmune diseases, including rheumatoid arthritis (RA). Oral administration of type II collagen (CII) has been proven to improve signs and symptoms in RA patients without troublesome toxicity. To investigate the mechanism of immune suppression mediated by orally administered antigen, we examined changes in serum IgG subtypes and T-cell proliferative responses to CII, and generation of IL-10-producing CD4+CD25+ T-cell subsets in an animal model of collagen-induced arthritis (CIA). We found that joint inflammation in CIA mice peaked at 5 weeks after primary immunization with CII, which was significantly less in mice tolerized by repeated oral feeding of CII before CIA induction. Mice that had been fed with CII also exhibited increased serum IgG1 and decreased serum IgG2a as compared with nontolerized CIA animals. The T-cell proliferative response to CII was suppressed in lymph nodes of tolerized mice also. Production of IL-10 and of transforming growth factor-beta from mononuclear lymphocytes was increased in the tolerized animals, and CD4+ T cells isolated from tolerized mice did not respond with induction of IFN-gamma when stimulated in vitro with CII. We also observed greater induction of IL-10-producing CD4+CD25+ subsets among CII-stimulated splenic T cells from tolerized mice. These data suggest that when these IL-10-producing CD4+CD25+ T cells encounter CII antigen in affected joints they become activated to exert an anti-inflammatory effect.