Increased Th17 cell frequency and poor clinical outcome in rheumatoid arthritis are associated with a genetic variant in the IL4R gene, rs1805010

Mechanism investigation of Duhuo Jisheng pill against rheumatoid arthritis based on a strategy for the integration of network pharmacology, molecular docking and in vivo experimental verification

CONTEXT

Duhuo Jisheng pill (DHJS) is a classic traditional Chinese medicine (TCM) formula for rheumatoid arthritis (RA). The effective components and therapeutic mechanisms of DHJS for treating RA are still unclear.

OBJECTIVE

To explore the potential mechanism of DHJS against RA by means of network pharmacology and experimental verification.

MATERIALS AND METHODS

A network pharmacology and molecular docking analysis based on phytochemistry was used to elucidate the mechanism of DHJS against RA. The targets of DHJS anti-RA active ingredient were obtained by searching TCMSP, ETCM and TCMSID. The RA model induced by collagen was established in Wistar rats. The rats in the DHJS group were administered doses of 0.5, 1.0 and 2.0 g/kg for a period of 10 d. The expression of targets was measured with Western blot.

RESULTS

Network pharmacology analysis showed that the anti-RA effect of DHJS was mediated by targets involved in immunity, inflammation and apoptosis, as well as PI3K-Akt and NF-κB signalling pathways. Of 2.0 g/kg DHJS significantly alleviated the ankle inflammation (IL-6: 62.73 ± 8.39 pg/mL, IL-1β: 50.49 ± 11.47 pg/mL, TNF-α: 16.88 ± 3.05 pg/mL, IL-17A: 12.55 ± 1.87 pg/mL, IL-10: 16.24 ± 3.00 pg/mL), comparing with the model group (IL-6: 92.02 ± 13.25 pg/mL, IL-1β: 71.85 ± 4.12 pg/mL, TNF-α: 25.64 ± 3.69 pg/mL, IL-17A: 22.14 ± 4.56 pg/mL, IL-10: 9.51 ± 3.03 pg/mL) (p < 0.05). Moreover, the protein expression of p-PI3K, p-AKT and p-p65 significantly decreased after DHJS administration.

CONCLUSIONS

DHJS could alleviate the collagen-induced arthritis (CIA) by the PI3K/AKT/NF-κB signalling pathway.

Immunopathogenic mechanisms of rheumatoid arthritis and the use of anti-inflammatory drugs

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by synovitis and symmetrical joint destruction. RA has become one of the key diseases endangering human health, but its etiology is not clear. Therefore, identifying the immunopathogenic mechanisms of RA and developing therapeutic drugs to treat autoimmune diseases have always been difficult. This article mainly reviews the immunopathogenic mechanism of RA and advances in the study of anti-inflammatory drugs in order to provide a reference for the treatment of RA and drug development in the future.

Advances in the role of helper T cells in autoimmune diseases

Autoimmune diseases are primary immune diseases in which autoreactive antibodies or sensitized lymphocytes destroy and damage tissue and cellular components, resulting in tissue damage and organ dysfunction. Helper T cells may be involved in the pathogenesis of autoimmune diseases under certain conditions. This review summarizes recent research on the role of helper T cells in autoimmune diseases from two aspects, helper T cell-mediated production of autoantibodies by B cells and helper T cell-induced activation of abnormal lymphocytes, and provides ideas for the treatment of autoimmune diseases. The abnormal expression of helper T cells promotes the differentiation of B cells that produce autoantibodies, which leads to the development of different diseases. Among them, abnormal expression of Th2 cells and T follicular helper cells is more likely to cause antibody-mediated autoimmune diseases. In addition, abnormal activation of helper T cells also mediates autoimmune diseases through the production of abnormal cytokines and chemokines. Helper T cells play an essential role in the pathogenesis of autoimmune diseases, and a full understanding of their role in autoimmune diseases is helpful for providing ideas for the treatment of autoimmune diseases.

Myeloid-Derived Suppressor Cells Promote the Progression of Primary Membranous Nephropathy by Enhancing Th17 Response

Several studies have confirmed that the myeloid-derived suppressor cells (MDSCs) are closely associated with autoimmune diseases, but their exact role in these processes remains largely unclear. Here, we investigated the role MDSCs in patients with primary membranous nephropathy (PMN). Compared to healthy controls (HCs), PMN patients showed significantly increased number of HLA-DR^-CD11b⁺CD33⁺ MDSCs in the peripheral blood, including both CD14⁺CD66b^- monocytic and CD14^-CD66b⁺ granulocytic MDSCs. The frequency of MDSCs was positively correlated with the level of serum anti-phospholipase A2 receptor (anti-PLA2R), 24-h urine protein quantification, and disease activity in PMN patients. Consistently, enhanced T helper 2 (Th2) and T helper 17 (Th17) immune responses were positively associated with plasma anti-PLA2R levels, 24-h urine protein quantification, and the disease activity in PMN patients. Moreover, compared to HCs, MDSCs from PMN patients exhibited significantly elevated arginase-1 (ARG-1) production and increased potential to promote Th17 differentiation in vitro in an ARG-1-dependent manner. This study directly demonstrates a pathogenic role for MDSCs in human PMN and provides a molecular mechanism for the pathogenesis of PMN. Our data show that MDSCs may promote PMN disease progression mainly by enhancing Th17 response. Therefore, MDSCs may be an important diagnostic, therapeutic, and prognostic marker for PMN diseases.

Genetic implications in the pathogenesis of rheumatoid arthritis; an updated review

Three important factors, including genetics, environment factors and autoimmunity play a role in the pathogenesis of rheumatoid arthritis (RA). The heritability of RA has been accounted to be 50-60%, while the HLA involvement in heritability of the disease has been accounted to be 10-40%. It has been documented that shared epitope (SE) alleles, such as HLA-DRB1*01 and DRB1*04, some HLA alleles like HLA-DRB1*13 and DRB1*15 are connected to RA susceptibility. An advanced classification of SE categorizes SE alleles into four main groups namely, S1, S2, S3D, and S3P. The S2 and S3P groups have been linked to susceptibility of seropositive RA. Various genome-wide association studies (GWAS) have discovered many susceptibility loci implicated in pathogenesis of RA. Some of the important single nucleotide polymorphisms (SNPs) linked to RA are TRAF1, STAT4, CTLA4, IRF5, CCR6, PTPN22, IL23R, and PADI4. HLA and non-HLA genes may discriminate anti-cyclic citrullinated peptide (anti-CCP) antibody-positive and anti-CCP-negative RA groups. Furthermore, risk of the disease has also been linked to environmental agents, mainly cigarette smoking. Pharmacogenomics has also confirmed SNPs or genetic patterns that might be linked to drugs responses. Different aspects of genetic involvement in the pathogenesis, etiology, and RA complications are reviewed in this article.

Immunopathogenic Mechanisms and Novel Immune-Modulated Therapies in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease of unknown etiology. It is characterized by the presence of rheumatoid factor and anticitrullinated peptide antibodies. The orchestra of the inflammatory process among various immune cells, cytokines, chemokines, proteases, matrix metalloproteinases (MMPs), and reactive oxidative stress play critical immunopathologic roles in the inflammatory cascade of the joint environment, leading to clinical impairment and RA. With the growing understanding of the immunopathogenic mechanisms, increasingly novel marked and potential biologic agents have merged for the treatment of RA in recent years. In this review, we focus on the current understanding of pathogenic mechanisms, highlight novel biologic disease-modifying antirheumatic drugs (DMRADs), targeted synthetic DMRADs, and immune-modulating agents, and identify the applicable immune-mediated therapeutic strategies of the near future. In conclusion, new therapeutic approaches are emerging through a better understanding of the immunopathophysiology of RA, which is improving disease outcomes better than ever.

Association of raised levels of IL-4 and anti-TPO with hyperprolactinemia

BACKGROUND AND OBJECTIVE

The modulatory role of prolactin in autoimmune regulation is well established. Hyperprolactinemia is often associated with autoimmune disease like systemic lupus erythematosus and autoimmune thyroid diseases. The objective was to compare levels of direct and indirect autoimmune factors in different categories of hyperprolactinemia cases and predict the direction of association between hyperprolactinemia and autoimmune factors, if any.

METHODS

A total of 102 hyperprolactinemia cases (>100 ng/mL serum prolactin level) were included along with 24 controls. Among 102 hyperprolactinemia cases, there were 36 idiopathic cases, 19 pituitary adenoma cases, 36 drug-induced cases, and 11 cases associated with other secondary/systemic diseases (chronic renal failure, chronic hepatic failure, etc).

MEASUREMENTS

Direct autoimmune markers, IL-2, IFN-γ, IL-4, and IL-5, were measured in serum by ELISA. Indirect autoimmune markers, anti-TPO, anti-tg, anti-CCP, VDRL, platelet count, and aPTT, were measured as per laboratory-defined protocol.

RESULTS

Serum levels of IL-4 and anti-TPO were significantly high in idiopathic hyperprolactinemia cases. Serum IL-4 levels were also significantly high in pituitary adenoma cases, drug-induced cases, and in cases with other secondary causes of hyperprolactinemia. Serum anti-TPO levels were also significantly high in drug-induced hyperprolactinemia cases.

CONCLUSION

No significant difference in autoimmune factors is observed between macroprolactinemia and true hyperprolactinemia. Serum IL-4 and anti-TPO were high in all categories of hyperprolactinemia. This suggests a possible association of hyperprolactinemia with autoimmune conditions (high IL-4 and anti-TPO), mostly subclinical. Thus, hyperprolactinemia case with serum prolactin level >100 ng/mL may require long-term follow-up for the development of autoimmune disease in future.

IL-4Rα Polymorphism Is Associated With Myasthenia Gravis in Chinese Han Population

Interleukin-4 (IL-4) is a potent growth and differentiation factor for B cells which play a vital role in the pathogenesis of myasthenia gravis (MG). IL-4 exerts its function by binding to three types of IL-4 receptor (IL-4R) complexes. IL-4Rα is the key component of the IL-4R complex. We hypothesize that polymorphism of IL-4Rα gene may be associated with the susceptibility and severity of MG. A Chinese cohort of 480 MG patients and 487 healthy controls were recruited. Polymorphisms of IL-4Rα gene were determined with SNPscan™ methods and compared between MG and control groups, as well as among MG subgroups. Rs2107356 and rs1805010 were found to be associated with adult thymoma associated MG, and rs1801275 was found to be associated with adult non-thymoma AChR-Ab positive MG. We did not found association between IL-4Rα polymorphism and the severity of MG. Genetic variations of IL-4Rα were found associated with the susceptibility of MG in Chinese Han population.

Imaging fibroblast activation protein to monitor therapeutic effects of neutralizing interleukin-22 in collagen-induced arthritis

Objectives

RA is a chronic autoimmune disease leading to progressive destruction of cartilage and bone. RA patients show elevated IL-22 levels and the amount of IL-22-producing Th cells positively correlates with the extent of erosive disease, suggesting a role for this cytokine in RA pathogenesis. The purpose of this study was to determine the feasibility of SPECT/CT imaging with 111In-labelled anti-fibroblast activation protein antibody (28H1) to monitor the therapeutic effect of neutralizing IL-22 in experimental arthritis.

Methods

Mice (six mice/group) with CIA received anti-IL-22 or isotype control antibodies. To monitor therapeutic effects after treatment, SPECT/CT images were acquired 24 h after injection of 111In-28H1. Imaging results were compared with macroscopic, histologic and radiographic arthritis scores.

Results

Neutralizing IL-22 before CIA onset effectively prevented arthritis development, reaching a disease incidence of only 50%, vs 100% in the control group. SPECT imaging showed significantly lower joint tracer uptake in mice treated early with anti-IL-22 antibodies compared with the control-treated group. Reduction of disease activity in those mice was confirmed by macroscopic, histological and radiographic pathology scores. However, when treatment was initiated in a later phase of CIA, progression of joint pathology could not be prevented.

Conclusion

These findings suggest that IL-22 plays an important role in CIA development, and neutralizing this cytokine seems an attractive new strategy in RA treatment. Most importantly, SPECT/CT imaging with 111In-28H1 can be used to specifically monitor therapy responses, and is potentially more sensitive in disease monitoring than the gold standard method of macroscopic arthritis scoring.

Genetic variants within the TNFRSF1B gene and susceptibility to rheumatoid arthritis and response to anti-TNF drugs: a multicenter study

BACKGROUND

Recent research suggests that genetic variants in the tumor necrosis factor receptor 2 (TNFRSF1B) gene may have an impact on susceptibility to rheumatoid arthritis (RA) and drug response. The present population-based case-control study was carried out to evaluate whether 5 tagging single-nucleotide polymorphisms (SNPs) within the TNFRSF1B gene are associated with the risk of RA and response to antitumor necrosis factor (TNF) drugs.

METHODS

The study population included 1412 RA patients and 1225 healthy controls. A subset of 596 anti-TNF-naive RA patients was selected to assess the association of TNFRSF1B SNPs and drug response according to the EULAR response criteria.

RESULTS

We found that carriers of the TNFRSF1Brs3397C allele had a significantly increased risk of developing RA (P=0.0006). Importantly, this association remained significant after correction for multiple testing. We also confirmed the lack of association of the TNFRSF1Brs1061622 SNP with the risk of RA in the single-SNP analysis (P=0.89), but also through well-powered meta-analyses (PDOM=0.67 and PREC=0.37, respectively). In addition, our study showed that carriers of the TNFRSF1Brs3397C/C, TNFRSF1Brs1061622G/G, and TNFRSF1Brs1061631A/A genotypes had an increased risk of having a worse response to anti-TNF drugs at the level of P less than 0.05 (P=0.014, 0.0085 and 0.028, respectively). We also observed that, according to a log-additive model, carriers of the TNFRSF1Brs3397C or TNFRSF1Brs1061622G alleles showed an increased risk of having worse response to anti-TNF medications (P=0.018 and 0.0059). However, the association of the TNFRSF1Brs1061622 SNP only reached marginal significance after correction for multiple testing according to a log-additive model (P=0.0059) and it was not confirmed through a meta-analysis (PDOM=0.12).

CONCLUSION

Our results suggest that the TNFRSF1Brs3397 variant may play a role in modulating the risk of RA, but does not provide strong evidence of an impact of TNFRSF1B variants in determining response to anti-TNF drugs.

Yi Shen Juan Bi Pill Ameliorates Bone Loss and Destruction Induced by Arthritis Through Modulating the Balance of Cytokines Released by Different Subpopulations of T Cells

The Yi Shen Juan Bi Pill (YSJB), a traditional Chinese compound herbal drug, has been used as an anti-rheumatic drug in clinical practice. Cartilage and bone destruction of inflamed joints is the hallmark of rheumatoid arthritis (RA). Our previous study suggested that YSJB had a protective effect on joint damage in collagen-induced (CIA) rats. However, the role and the mechanism of YSJB in inflammation-induced bone loss are unavailable. The current study aimed to further evaluate the effect of YSJB on the joint destruction and the systemic bone loss, and to clarify the potential mechanism. CIA model was generated by using collagen II and incomplete Freund's adjuvant in Sprague-Dawley rats. After 4 weeks treatment, arthritic index, tissue pathology, micro-computed tomography scanning (μ-CT), and bone mineral density (BMD) analysis were performed. YSJB decreased arthritic scores and bone destruction; improved the BMD of lumbar vertebrae and bone volume fraction of inflamed joints. Moreover, YSJB significantly decreased the production of serum bone resorption markers, including Tartrate-Resistant Acid Phosphatase (TRACP), N-terminal telopeptide of type I collagen and C-terminal telopeptide of type I collagen. Meanwhile, it increased the level of serum bone formation marker type I collagen N-terminal propeptide. These results revealed that YSJB ameliorated bone destruction and reduced bone loss induced by arthritis. We have previously showed that Tregs inhibited osteoclast differentiation and bone resorption in vitro. Furthermore, others suggested that abnormality of Th1, Th17 may contribute to bone destruction. Here, we showed YSJB significantly up-regulated the percentage of Tregs, while also down-regulated the percentage of Th1 and Th17 cells. Our findings provide the evidence that YSJB ameliorates the severity of disease and joint degradation, and reduces systemic bone loss induced by arthritis. We propose YSJB modulates the balance of T cell phenotype, which affects the activation and differentiation of osteoclasts.

Effector T helper cell populations are elevated in the bone marrow of rheumatoid arthritis patients and correlate with disease severity

This study is to investigate the frequencies of T-helper (Th)22, Th17 and Th1 cells and the levels of related cytokines in subchondral bone marrow in patients with rheumatoid arthritis (RA). Bone marrow and peripheral blood samples were collected from RA, osteoarthritis (OA) patients and healthy controls. The frequencies of Th22, Th17, and Th1 cells were examined by flow cytometry. Levels of interleukin (IL)-22, IL-17 and IFN-γ were examined by ELISA. Disease Activity Score in 28 joints (DAS28) of RA patients were analyzed. Bone marrow Th22, Th17 and Th1 cells in RA patients were markedly increased comparing to OA or healthy controls. Each T cell subset in bone marrow was elevated comparing with that in the peripheral blood in RA patients. Consistently, plasma levels of IL-22 and IL-17 were elevated in RA patients, and the elevation was more notable in the bone marrow than in the peripheral blood. Additionally, the percentages of Th22, Th17 and Th1 cells as well as the levels of IL-22 and IL-17 in bone marrow were positively correlated with DAS28. These results suggest that local pro-inflammatory Th cells are elevated in bone marrow, which may play an important role in situ in RA and contribute to the pathogenesis of in RA.

Genetics of rheumatoid arthritis susceptibility, severity, and treatment response

A decade after the first genome-wide association study in rheumatoid arthritis (RA), a plethora of genetic association studies have been published on RA and its clinical or serological subtypes. We review the major milestones in the study of the genetic architecture of RA susceptibility, severity, and response to treatment. We set the scientific context necessary for non-geneticists to understand the potential clinical applications of human genetics and its significance for a stratified approach to the management of RA in the future.

Interaction among activated lymphocytes and mesenchymal cells through podoplanin is critical for a high IL-17 secretion

Background

During chronic inflammation, immune cells, notably Th17 cells, infiltrate the inflammatory site and interact with local mesenchymal cells. Applied to rheumatoid arthritis (RA), the aim is to study the interactions between synoviocytes and peripheral blood mononuclear cells (PBMC) with a focus on the Th17 pathway and to identify a mechanism which leads to high IL-17 secretion with an interest on podoplanin.

Methods

PBMC from healthy donors and RA patients were co-cultured with RA synoviocytes during 48 h, in the presence or not of phytohemagglutinin. An antibody against podoplanin was used in co-culture. Cytokine production (IL-6, IL-1β and IL-17) was measured by ELISA and cell staining (CD3, CD4, IL-17 and podoplanin) by flow cytometry.

Results

In control conditions, IL-6 and IL-1β production was increased in PBMC-synoviocyte co-culture compared to PBMC alone (p = 0.02). No additional effect was observed with PBMC activation. Flow cytometry analysis showed no difference in the percentage of Th17 cells in activated PBMC alone or with synoviocytes (p = 0.4), indicating that Th17 differentiation requires only T cell activation. Conversely, IL-17 production was highly increased in co-cultures with activated PBMC vs. activated PBMC alone (p = 0.002). Transwell experiments confirm that cell-cell contact was critical for IL-17 secretion. The incubation of either PBMC or synoviocytes with an anti-podoplanin antibody decreased IL-17 secretion by 60 % (p = 0.008).

Conclusions

Interactions between resting PBMC and synoviocytes are sufficient to induce IL-6 and IL-1β production. Both PBMC activation and cell interactions are needed to induce a high IL-17 secretion. Podoplanin contributes at the level of both lymphocytes and synoviocytes.

Arginase-1-dependent promotion of TH17 differentiation and disease progression by MDSCs in systemic lupus erythematosus

Expansion of myeloid-derived suppressor cells (MDSCs) has been documented in some murine models and patients with autoimmune diseases, but the exact role of MDSCs in this process remains largely unknown. The current study investigates this question in patients with systemic lupus erythematosus (SLE). Patients with active SLE showed a significant increase in HLA-DR(-)CD11b(+)CD33(+)MDSCs, including both CD14(+)CD66b(-)monocytic and CD14(-)CD66b(+)granulocytic MDSCs, in the peripheral blood compared to healthy controls (HCs). The frequency of MDSCs was positively correlated with the levels of serum arginase-1 (Arg-1) activity, T helper 17 (TH17) responses, and disease severity in SLE patients. Consistently, in comparison with MDSCs from HCs, MDSCs from SLE patients exhibited significantly elevated Arg-1 production and increased potential to promote TH17 differentiation in vitro in an Arg-1-dependent manner. Moreover, in a humanized SLE model, MDSCs were essential for the induction of TH17 responses and the associated renal injuries, and the effect of MDSCs was Arg-1-dependent. Our data provide direct evidence demonstrating a pathogenic role for MDSCs in human SLE. This study also provides a molecular mechanism of the pathogenesis of SLE by demonstrating an Arg-1-dependent effect of MDSCs in the development of TH17 cell-associated autoimmunity, and suggests that targeting MDSCs or Arg-1 may offer potential therapeutic strategies for the treatment of SLE and other TH17 cell-mediated autoimmune diseases.

Interleukin-6-dependent influence of nociceptive sensory neurons on antigen-induced arthritis

INTRODUCTION

Interleukin-6 (IL-6) is an important mediator of inflammation. In addition to cells involved in inflammation, sensory nociceptive neurons express the IL-6 signal-transducer glycoprotein 130 (gp130). These neurons are not only involved in pain generation but also produce neurogenic inflammation by release of neuropeptides such as calcitonin gene-related peptide (CGRP). Whether IL-6 activation of sensory neurons contributes to the induction of inflammation is unknown. This study explored whether the action of IL-6 on sensory neurons plays a role in the generation of neurogenic inflammation and arthritis induction.

METHODS

In SNS-gp130(-/-) mice lacking gp130 selectively in sensory neurons and appropriate control littermates (SNS-gp130(flox/flox)), we induced antigen-induced arthritis (AIA), and assessed swelling, histopathological arthritis scores, pain scores, expression of CGRP in sensory neurons, serum concentrations of CGRP and cytokines, and the cytokine release from single cell suspensions from lymph nodes and spleens. In wild-type mice CGRP release was determined during development of AIA and, in cultured sensory neurons, upon IL-6 stimulation.

RESULTS

Compared to SNS-gp130(flox/flox) mice SNS-gp130(-/-) mice showed significantly weaker initial swelling, reduced serum concentrations of CGRP, IL-6, and IL-2, no inflammation-evoked upregulation of CGRP in sensory neurons, but similar histopathological arthritis scores during AIA. During the initial swelling phase of AIA, CGRP was significantly increased in the serum, knee and spleen. In vitro, IL-6 augmented the release of CGRP from cultured sensory neurons. Upon antigen-specific restimulation lymphocytes from SNS-gp130(-/-) mice released more interleukin-17 and interferon-γ than lymphocytes from SNS-gp130(flox/flox) mice. In naive lymphocytes from SNS-gp130(flox/flox) and SNS-gp130(-/-) mice CGRP reduced the release of IL-2 (a cytokine which inhibits the release of interleukin-17 and interferon-γ).

CONCLUSIONS

IL-6 signaling in sensory neurons plays a role in the expression of arthritis. Selective deletion of gp130 signaling in sensory neurons reduces the swelling of the joint (most likely by reducing neurogenic inflammation) but increases some proinflammatory systemic cellular responses such as the release of interleukin-17 and interferon-γ from lymphocytes upon antigen-specific restimulation. Thus IL-6 signaling in sensory neurons is not only involved in pain generation but also in the coordination of the inflammatory response.

Commentary: IL-4 and IL-13 receptors and signaling

Interleukin (IL)-4 and IL-13 were discovered approximately 30years ago and were immediately linked to allergy and atopic diseases. Since then, new roles for IL-4 and IL-13 and their receptors in normal gestation, fetal development and neurological function and in the pathogenesis of cancer and fibrosis have been appreciated. Studying IL-4/-13 and their receptors has revealed important clues about cytokine biology and led to the development of numerous experimental therapeutics. Here we aim to highlight new discoveries and consolidate concepts in the field of IL-4 and IL-13 structure, receptor regulation, signaling and experimental therapeutics.

The role of the Th17 cytokines IL-17 and IL-22 in Rheumatoid Arthritis pathogenesis and developments in cytokine immunotherapy

Over the past few years, the importance of Interleukin (IL)-17 and T helper (Th)17 cells in the pathology of Rheumatoid Arthritis (RA) has become apparent. RA is a systemic autoimmune disease that affects up to 1% of the population worldwide. It is characterized by an inflamed, hyperplastic synovium with pannus formation, leading to bone and cartilage destruction in the joints. By the production of effector cytokines like IL-17 and IL-22, the T helper 17 subset protects the host against bacterial and fungal infections, but it can also promote the development of various autoimmune diseases like RA. Hence, the Th17 pathway recently became a very interesting target in RA treatment. Up to now, several therapies targeting the Th17 cells or its effector cytokines have been tested, or are currently under investigation. This review clarifies the role of Th17 cells and its cytokines in the pathogenesis of RA, and provides an overview of the clinical trials using immunotherapy to target this particular T helper subset or the two main effector cytokines by which the Th17 cells exert their function, IL-17 and IL-22.

Interleukin-22 and rheumatoid arthritis: emerging role in pathogenesis and therapy

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by synovial inflammation and resultant progressive joint damage. It has become increasingly evident that cytokines play an important role in the pathogenesis of RA. Interleukin-22 (IL-22) is a member of the IL-10 cytokine family. Recent findings suggest that not only the expression of IL-22 is abnormal both in RA patients and in arthritis mice but also the aberrant IL-22 performs significantly in disease onset of RA. In this paper, we focus on the critical role of IL-22 in RA. Hopefully, the information obtained may lead to a better understanding of the pathogenesis and development of novel therapeutic strategies for this systemic autoimmune disease.

Th17 cells in autoimmune diseases

Th17 cells are a new subset of CD4(+) T cells involved in the clearance of extracellular pathogens and fungi. Accumulating evidence suggests that Th17 cells and their signature cytokines have a pivotal role in the pathogenesis of multiple autoimmune-mediated inflammatory diseases. Here, we summarize recent research progress on Th17 function in the development and pathogenesis of autoimmune diseases. We also propose to identify new small molecule compounds to manipulate Th17 function for potential therapeutic application to treat human autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, inflammatory bowel disease, and multiple sclerosis.

The effect of IL-4 gene polymorphisms on cytokine production in patients with chronic periodontitis and in healthy controls

Chronic periodontitis (CP) is an inflammatory disease of the teeth-supporting tissues in which genetic predisposition, dental plaque bacteria, and immune mechanisms all play important roles. The aim of this study was to evaluate the occurrence of IL-4 gene polymorphisms in chronic periodontitis and to investigate the association between polymorphisms and cytokines production after bacterial stimulation. Sixty-two subjects (47 CP patients and 15 healthy controls) with detected two polymorphisms in the IL-4 gene (-590C/T and intron 3 VNTR) were examined. Production of cytokines (IL-1α, IL-1β, IL-4, IL-5, IL-6, IL-10, IL-17, TNFα, INFγ, and VEGF) was studied after in vitro stimulation of isolated peripheral blood by mitogens (Pokeweed mitogen, Concanavalin A), dental plaque bacteria (Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, and Prevotella intermedia), and Heat Shock Protein (HSP) 70 by the Luminex multiplex cytokine analysis system. The results were correlated with IL-4 genotypes in patients with CP and healthy controls. The mononuclear cells isolated from peripheral blood of CP patients with selected IL-4 polymorphisms significantly altered the production of IFNγ, IL-10, IL-1β, IL-1α, TNFα, and IL-6 after stimulation by HSP 70 or selected bacteria (from P < 0.001 to P < 0.05). IL-4 gene polymorphisms may influence the function of mononuclear cells to produce not only interleukin-4 but also other cytokines, especially in patients with CP.