Update on cytokines in rheumatoid arthritis

An ADAM10 Exosite Inhibitor Is Efficacious in an In Vivo Collagen-Induced Arthritis Model

Rheumatoid arthritis is a systemic autoimmune inflammatory disease that affects millions of people worldwide. There are multiple disease-modifying anti-rheumatic drugs available; however, many patients do not respond to any treatment. A disintegrin and metalloproteinase 10 has been suggested as a potential new target for RA due to its role in the release of multiple pro- and anti-inflammatory factors from cell surfaces. In the present study, we determined the pharmacokinetic parameters and in vivo efficacy of a compound CID3117694 from a novel class of non-zinc-binding inhibitors. Oral bioavailability was demonstrated in the blood and synovial fluid after a 10 mg/kg dose. To test efficacy, we established the collagen-induced arthritis model in mice. CID3117694 was administered orally at 10, 30, and 50 mg/kg/day for 28 days. CID3117694 was able to dose-dependently improve the disease score, decrease RA markers in the blood, and decrease signs of inflammation, hyperplasia, pannus formation, and cartilage erosion in the affected joints compared to the untreated control. Additionally, mice treated with CID 3117694 did not exhibit any clinical signs of distress, suggesting low toxicity. The results of this study suggest that the inhibition of ADAM10 exosite can be a viable therapeutic approach to RA.

Peimine suppresses collagen-induced arthritis, activated fibroblast-like synoviocytes and TNFα-induced MAPK pathways

BACKGROUND AND PURPOSE

Peimine (PM), a main isosterol alkaloid component isolated from the bulbs of traditional Chinese herb Fritillaria cirrhosa D. Don, has been demonstrated to exhibit multiple pharmacological properties, including anti-inflammation, anti-cancer and pain suppression. However, its effect on rheumatoid arthritis (RA) remains unknown. In the present study, we investigated the effect of PM on collagen-induced arthritis (CIA) rats in vivo and its inhibition on destructive behaviors of arthritic fibroblast-like synoviocytes (FLSs) in vitro.

METHODS

Arthritis was induced in rats by chicken type II collagen. Arthritis score, radiological evaluation, and histopathological assessment were used to evaluate the therapeutic effects of PM on CIA rats. EdU assay, wound healing assay and real-time PCR were used to examine the inhibitory effect of PM on proliferation, migration, and over-expression of pro-inflammatory cytokines in TNFα-induced arthritic FLSs. TRAP staining and scanning electron microscopy were used to analyze the effect of PM on osteoclastogensis and bone resorption. Western blot was used to reveal PM's molecular mechanism of action on RA.

RESULTS

PM significantly suppressed synovitis and bone destruction in CIA rats. In vitro experiments showed that PM treatment significantly inhibited TNFα-induced destructive behaviors of arthritic FLSs, including over-proliferation, migration and over-expression of pro-inflammatory cytokines. Additionally, RANKL-induced osteoclast formation and bone-resorpting function were also inhibited by PM. Further molecular mechanism studies revealed that PM treatment significantly suppressed TNFα-induced activations of MAPKs (ERK, JNK and p38) in arthritic FLSs.

CONCLUSION

Our findings provide strong evidence that PM has the potential to be developed as a therapeutic agent for patients with RA.

Apolipoprotein B binds to enolase-1 and aggravates inflammation in rheumatoid arthritis

OBJECTIVE

Immune cells from patients with rheumatoid arthritis (RA) express more enolase-1 (ENO1) on their surface than those from healthy subjects, and they elicit an enhanced inflammatory response. This study is aimed to identify the ligands of ENO1 that could promote inflammatory loops in vitro and enhance the arthritis severity in vivo.

METHODS

ENO1-binding proteins in RA synovial fluid were identified by mass spectromety, and affinity to ENO1 was evaluated by means of a ligand blotting and binding assay, surface plasmon resonance and confocal microscopy. Proinflammatory response by the interaction between ENO1 and apolipoprotein B (apoB) was tested in vitro and in vivo using peripheral blood mononuclear cells and a K/BxN serum transfer arthritis model and low-density lipoproteins receptor (LDLR) knockout mice.

RESULTS

ApoB in the synovid fluid of patients with RA was identified as a specific ligand to ENO1 with a higher affinity than plasminogen, a known ENO1 ligand. ApoB binding to ENO1 on monocytes elicited the production of tumour necrosis factor-α, interleukins (IL)-1β and IL-6 through both p38 mitogen-activated protein kinase and NF-κB pathways. In the K/BxN serum transfer arthritis model, administration of apoB increased the production of proinflammatory cytokines and exaggerated arthritis severity. The severity of K/BxN serum transfer arthritis in LDLR knockout mice was comparable with wild-type mice.

CONCLUSIONS

A key component of atherogenic lipids, apoB, aggravated arthritis by potentiating the inflammatory response via its interaction with ENO1 expressed on the surface of immune cells. This suggests a novel mechanism by which lipid metabolism regulates chronic inflammation in RA.

Discovery of New Benzothiazine Derivative as Modulator of Pro- and Anti-inflammatory Cytokines in Rheumatoid Arthritis

The anti-inflammatory activities of benzothiazine and pyrazole derivatives are well documented. A series of novel N'-arylmethylidene-2-(3,4-dimethyl-5,5-dioxidopyrazolo(4,3 c)(1,2) benzothiazin-2(4H)yl) acetohydrazide compounds were previously synthesized by combining benzothiazine and pyrazole moieties into a single nucleus. The current study investigates the anti-arthritic potential of 3-ethoxy-4-hydroxyphenyl derivative (EHP) and its possible mechanism in arthritic rat model. Sprague-Dawley rats were induced rheumatoid arthritis with Freund's complete adjuvant and treated with EHP and piroxicam. At the end of the study, arthritic score was calculated, and ankle joint histopathology was performed using hematoxylin and eosin staining. Real-time reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to determine mRNA expression and protein levels of various inflammatory markers, respectively. In vitro concanavalin A (ConA)-stimulated splenocyte proliferation was measured. Serum levels of C-reactive protein (CRP), urea, creatinine, aspartate aminotransferase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) were also determined. EHP significantly attenuated macroscopic arthritic score, joint histopathological lesions, and CRP levels. Treatment with EHP significantly reduced pro-inflammatory tissue necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-кB), interleukin-17 (IL-17), and prostaglandin-E2 (PGE2) levels and increased the levels of anti-inflammatory interleukin-4 (IL-4) and interleukin-10 (IL-10). ConA-stimulated splenocyte proliferation was also significantly suppressed by treatment with EHP. Normalizing all hematological markers and ALP levels, EHP did not display any sign of nephrotoxicity and hepatotoxicity as determined by urea, creatinine, ALT, and AST levels. In conclusion, EHP possesses significant anti-arthritic property which may be attributed to its anti-inflammatory and immunomodulatory effects.

Foxo4- and Stat3-dependent IL-10 production by progranulin in regulatory T cells restrains inflammatory arthritis

Progranulin (PGRN) restrains inflammation and is therapeutic against inflammatory arthritis; however, the underlying immunological mechanism remains unknown. In this study, we demonstrated that anti-inflammatory cytokine IL-10 was a critical mediator for PGRN-mediated anti-inflammation in collagen-induced arthritis by using PGRN and IL-10 genetically modified mouse models. IL-10 green fluorescent protein reporter mice revealed that regulatory T (T_reg) cells were the predominant source of IL-10 in response to PGRN. In addition, PGRN-mediated expansion and activation of T_reg cells, as well as IL-10 production, depends on JNK signaling, but not on known PGRN-activated ERK and PI3K pathways. Furthermore, microarray and chromatin immunoprecipitation sequencing screens led to the discovery of forkhead box protein O4 and signal transducer and activator of transcription 3 as the transcription factors required for PGRN induction of IL-10 in T_reg cells. These findings define a previously unrecognized signaling pathway that underlies IL-10 production by PGRN in T_reg cells and present new insights into the mechanisms by which PGRN resolves inflammation in inflammatory conditions and autoimmune diseases, particularly inflammatory arthritis.-Fu, W., Hu, W., Shi, L., Mundra, J. J. Xiao, G., Dustin, M. L., Liu, C. Foxo4- and Stat3-dependent IL-10 production by progranulin in regulatory T cells restrains inflammatory arthritis.

Clinical effects of tocilizumab on cytokines and immunological factors in patients with rheumatoid arthritis

Interleukin (IL)-6 is one of the crucial proinflammatory cytokines. The dysregulation of IL-6 plays a pivotal role in rheumatoid arthritis (RA) and is involved in several of the common clinical manifestations associated with active RA. Recent therapies targeting IL-6 and tumor necrosis factor (TNF) have resulted in clinical improvements in signs and symptoms, disability and quality of life in patients with early and long-standing RA. Because it has been demonstrated that cytokines and inflammatory/immunological factors appear to be important and sensitive mediators in RA patients treated with tocilizumab and with anti-TNF biologics, it is important to investigate whether tocilizumab administration has any effect(s) on the profiles of cytokines and inflammatory/immunological factors and whether these changes correlate with the clinical improvement in RA disease activity. In this review, we discuss the effects on cytokine regulation and the differentiation of immune cells, especially T cells, after tocilizumab therapy in patients with RA.

The Anti-inflammatory Effect of GV1001 Mediated by the Downregulation of ENO1-induced Pro-inflammatory Cytokine Production

GV1001 is a peptide derived from the human telomerase reverse transcriptase (hTERT) sequence that is reported to have anti-cancer and anti-inflammatory effects. Enolase1 (ENO1) is a glycolytic enzyme, and stimulation of this enzyme induces high levels of pro-inflammatory cytokines from concanavalin A (Con A)-activated peripheral blood mononuclear cells (PBMCs) and ENO1-expressing monocytes in healthy subjects, as well as from macrophages in rheumatoid arthritis (RA) patients. Therefore, this study investigated whether GV1001 downregulates ENO1-induced pro-inflammatory cytokines as an anti-inflammatory peptide. The results showed that GV1001 does not affect the expression of ENO1 in either Con A-activated PBMCs or RA PBMCs. However, ENO1 stimulation increased the production of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, and these cytokines were downregulated by pretreatment with GV1001. Moreover, p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB were activated when ENO1, on the surface of Con A-activated PBMCs and RA PBMCs, was stimulated, and they were successfully suppressed by pre-treatment with GV1001. These results suggest that GV1001 may be an effective anti-inflammatory peptide that downregulates the production of pro-inflammatory cytokines through the suppression of p38 MAPK and NF-κB activation following ENO1 stimulation.

Effect of galantamine on adjuvant-induced arthritis in rats

Stimulation of the vagus nerve suppresses cytokine production and macrophage activation, via the interaction of its neurotransmitter acetylcholine (ACh) with the α7 subunit of the nicotinic acetylcholine receptor (α7nAChR), present on neurons and inflammatory cells. The present study aimed to verify the potential anti-inflammatory effect of galantamine against experimental arthritis induced in rats. Fourteen days post adjuvant injection, Sprague-Dawley rats were treated orally with three doses of galantamine (1.25, 2.5 and 5 mg/kg) or leflunomide (10 mg/kg) for 2 weeks and arthritis progression was assessed by hind paw swelling. Additionally, serum biomarkers, viz., anti-cyclic citrullinated peptide antibodies (Anti-CCP), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) and monocyte chemoattractant protein-1 (MCP-1) were measured. Radiological examination of the hind paws was also carried out to evaluate the degree of joint damage. Adjuvant arthritis led to a significant weight loss, marked swelling of the hind paw and alteration in the serum levels of anti-CCP, TNF-α, IL-10 and MCP-1. These alterations were associated with significant radiological changes of the joints. Galantamine, in a dose-dependent manner, reduced significantly all biomarkers of inflammation, with the highest dose showing the best beneficial anti-inflammatory effect that was superior in magnitude to the reference drug leflunomide in most of the studied parameters. In conclusion, these results suggest that galantamine may represent a novel, inexpensive and effective therapeutic strategy in the treatment of rheumatoid arthritis.

Association between KIR gene polymorphisms and rheumatoid arthritis susceptibility: A meta-analysis

OBJECTIVES

The results of studies on association between KIR (killer cell immunoglobulin-like receptors) polymorphisms and susceptibility to RA (rheumatoid arthritis) are inconsistent. To comprehensively evaluate the effect of KIR polymorphisms on the risk of RA, a meta-analysis was carried out.

METHODS

The Web of Science, PubMed, the Chinese Biomedical Database (CBM) and Chinese National Knowledge Infrastructure (CNKI) databases were systematically searched to select studies on the association between KIR polymorphisms and RA. The odds ratio (OR) with 95% confidence interval (95%CI) was obtained.

RESULTS

Nine qualified case-control studies were included in this meta-analysis. The results showed there were two positive associations of 2DL1, 2DS1 (OR2DL1=2.20, 95%CI=1.20-4.01, Praw=0.01, PFDR=0.03; OR2DS1=1.84, 95%CI=1.19-2.85, Praw=0.006, PFDR=0.018) and one negative association of 2DL3 (OR2DL3=0.42, 95%CI=0.22-0.79, Praw=0.006, PFDR=0.018) with susceptibility to RA in East Asians, but not in Caucasians.

CONCLUSION

The current meta-analysis provides evidence that 2DL3 might be a potential protective factor and 2DL1, 2DS1 might be risk factors for RA in East Asians but not in Caucasians.

Distribution of interleukin-10 family cytokines in serum and synovial fluid of patients with inflammatory arthritis reveals different contribution to systemic and joint inflammation

Evidence exists that interleukin (IL)-10 family cytokines may be involved in the pathogenesis of rheumatoid arthritis (RA). We sought to determine whether or not these cytokines are involved in psoriatic arthritis (PsA). We conducted a prospective study on patients with PsA, RA and osteoarthritis (OA); healthy controls (HC) were also included. We analysed IL-20, IL-24 and IL-19 serum and synovial fluid (SF) levels and change of serum levels following treatment with biological agents. IL-20 serum levels were increased in PsA and RA compared with OA patients and HC and with matched SF levels. IL-24 serum levels in PsA, RA and OA patients were higher than those in HC and also with respect to matched SF in PsA. IL-19 serum levels were higher in HC and OA compared with PsA and RA patients; IL-19 SF levels were higher in PsA and RA compared with OA patients, and in PsA compared with RA patients. PsA and RA patients showed a reduction of IL-19 serum levels after biological treatment. Therefore, IL-19 seems to be involved mainly in the joint inflammation, whereas IL-20 and IL-24 appear to participate mainly in the systemic responses. These findings may further the comprehension of the contribution of these cytokines to the inflammatory response involved in chronic arthritis, as well as to the development of novel therapeutic strategies.

Reduced B lymphoid kinase (Blk) expression enhances proinflammatory cytokine production and induces nephrosis in C57BL/6-lpr/lpr mice

BLK, which encodes B lymphoid kinase, was recently identified in genome wide association studies as a susceptibility gene for systemic lupus erythematosus (SLE), and risk alleles mapping to the BLK locus result in reduced gene expression. To determine whether BLK is indeed a bona fide susceptibility gene, we developed an experimental mouse model, namely the Blk^+/−.lpr/lpr (Blk^+/−.lpr) mouse, in which Blk expression levels are reduced to levels comparable to those in individuals carrying a risk allele. Here, we report that Blk is expressed not only in B cells, but also in IL-17-producing γδ and DN αβ T cells and in plasmacytoid dendritic cells (pDCs). Moreover, we found that solely reducing Blk expression in C57BL/6-lpr/lpr mice enhanced proinflammatory cytokine production and accelerated the onset of lymphoproliferation, proteinuria, and kidney disease. Together, these findings suggest that BLK risk alleles confer susceptibility to SLE through the dysregulation of a proinflammatory cytokine network.

Therapeutic effect of dimethyl dimethoxy biphenyl dicarboxylate on collagen-induced arthritis in rats

OBJECTIVE

To study the effect of oral administration of dimethyl dimethoxy biphenyl dicarboxylate (DDB) on adjusting angiogeneic/inflammatory mediators and ameliorating the pathology of bones in rats with collagen-induced arthritis (CIA).

METHODS

Wistar rat model of CIA was set up using bovine collagen type II. Fifty rats were divided into five groups randomly: normal, CIA model, DDB treatment, methotrexate (MTX) treatment, and combined DDB+MTX treatment. Ankle joints of rats were imaged with digital X-ray machine to show the destruction of joints. Fore and hind paw and knee joints were removed above the ankle joint then processed for haematoxylin and eosin staining. Plasma levels of vascular endothelial growth factor (VEGF), platelet derived growth factor, interleukin-8 (IL-8), IL-4, tumor necrosis factor α (TNF-α), and cyclooxygenase-2 (COX-2) were quantified by enzyme-linked immunosorbent assay. Nitric oxide levels were detected by Griess reagent.

RESULTS

Compared with the CIA model group, a remarkable reduction in various angiogenic (VEGF and IL-8) and inflammatory mediators (TNF-α, IL-4 and COX-2) after treatment with DDB either alone or combined with MTX P<0.05 or P<0.01). Histopathological and X-ray findings were confirmatory to the observed DDB anti-arthritic effect. The DDB-treated group showed amelioration in signs of arthritis which appeared essentially similar to normal.

CONCLUSION

Our data shed light on the therapeutic efficacy of DDB in experimental rheumatoid arthritis (RA) compared with a choice drug (MTX) and it may be offered as a second-line drug in the treatment of RA.

The regulatory role of immunosuppressants on immune abnormalities in acute pancreatitis

The uncontrolled progression of the inflammatory cascade is the main cause underlying the development of multiple organ dysfunction syndrome (MODS) in acute pancreatitis. In this study, we investigated the effects of several immunosuppressants on mitigating the systemic inflammatory reaction syndrome (SIRS) and the compensatory anti-inflammatory response syndrome (CARS) associated with acute pancreatitis. A total of 93 male Sprague Dawley rats were divided into 5 groups: group 1 was the sham group and group 2 underwent laparoscopic intrapancreatic duct injection of sodium taurocholate to induce pancreatitis. The remaining 3 groups were the same as group 2, with the addition of methylprednisolone, cyclophosphamide or methotrexate treatment (metastab, CTX or MTX groups, respectively). Following establishment of the acute pancreatitis model, the serum levels of inflammatory and anti-inflammatory cytokines in groups 2, 3, 4 and 5 were found to be significantly elevated. Following immunosuppressant administration, the levels of all inflammatory and anti-inflammatory cytokines investigated in groups 3, 4 and 5 were decreased compared to those in group 2. The pancreatic amylase levels and pancreatic wet weight (PWW) were also decreased in groups 3, 4 and 5 compared to those in group 2. Therefore, immunosuppressants may reduce inflammation-related cytokine levels in acute pancreatitis and relieve disease progression.

Associations of interleukin-4 receptor gene polymorphisms (Q551R, I50V) with rheumatoid arthritis: evidence from a meta-analysis

BACKGROUND AND AIMS

Published data on the associations between interleukin-4 receptor (IL-4R) gene polymorphisms (Q551R, I50V) and rheumatoid arthritis (RA) risk are controversial. To quantitatively evaluate the relationships, a meta-analysis was performed.

METHODS

Studies were identified from the databases of PubMed, MEDLINE, Chinese Biomedical Literature Database, and Chinese National Knowledge Infrastructure, with the last report up to June 2012. The effect summary odds ratio (OR) and 95% confidence interval (CI) were obtained.

RESULTS

A total of six separate comparisons involving 2173 patients and 1892 controls were included to assess the association of IL-4R gene Q551R polymorphism and RA susceptibility. Overall, no significantly elevated RA risk was found in the meta-analysis. The pooled OR for the minor R allele was 0.942 (95% CI: 0.848-1.047, p=0.268) in patients with RA. After stratification by ethnicity, there was still no significant association detected in the European population (OR=0.979, 95% CI: 0.875-1.094). As for I50V polymorphism, there were four comparisons involving 1653 patients and 1584 controls in this meta-analysis. The pooled OR for the V allele was 1.104 (95% CI: 1.001-1.217) in RA, the V allele of the IL-4R gene I50V variant might be a risk factor for RA. However, the relationship between the V allele of IL-4R gene I50V polymorphism and rheumatoid factor positive in patients with RA was not identified through a minor meta-analysis, including four independent relevant comparisons.

CONCLUSIONS

This meta-analysis indicates that the I50V polymorphism of IL-4R gene may confer susceptibility to RA; up to now, there is still not enough evidence to reveal the association of the IL-4R gene Q551R polymorphism with RA risk.

Serum macrophage migration inhibitory factor levels are correlated with response to tocilizumab therapy in patients with rheumatoid arthritis

To examine the relationship between serum cytokine levels and response to tocilizumab in patients with RA. The disease status of 21 RA patients was assessed at baseline and after 12 weeks of tocilizumab treatment, using the clinical disease activity index (CDAI). Clinical response to tocilizumab was defined as an improvement of >50% from the baseline CDAI. Serum cytokine levels were quantified using double-ligand ELISA for TNF-α, IL-6, CCL2, CCL3, CXCL8, CXCL10, CX3CL1, and macrophage migration inhibitory factor (MIF). After 12 weeks of tocilizumab treatment, there was a significant overall reduction in RA disease activity (CDAI), from 22.4 ± 11.3 to 9.2 ± 6.6 (p < 0.0001), across the entire patient group. After 12 weeks of tocilizumab treatment, 14 patients achieved a >50% improvement (the responder group), but there were no significant responses in the other 7 patients (the non-responder group). The erythrocyte sedimentation rate levels, the positive % of anti-cyclic citrullinated protein antibody and patients (%) receiving methotrexate in combination with tocilizumab were significantly higher in the responder group than in the non-responder group. Although serum baseline levels of CCL2 and CXCL8 were higher in the responder group than in the non-responder group, there were no significant changes in these chemokine levels after treatment. The serum MIF levels, but not the levels of other cytokines, in the responder group were significantly decreased after tocilizumab treatment. Our results suggest that tocilizumab differentially regulates serum cytokine profiles in patients with RA, and MIF regulation in patients with active RA may be sensitive to anti-IL-6 therapy.

Associations of vitamin D receptor gene polymorphisms FokI and BsmI with susceptibility to rheumatoid arthritis and Behçet's disease in Tunisians

OBJECTIVES

Reports of immunomodulating effects of vitamin D suggest a need for examining allele and genotype frequencies of the vitamin D nuclear receptor gene (VDR) in patients with autoimmune diseases. T-helper-1 (Th1) counts in peripheral blood are increased in both rheumatoid arthritis (RA) and Behçet's disease (BD). We studied VDR polymorphisms in patients with these two diseases in Tunisia.

METHODS

In 108 patients with RA, 131 patients with BD, and 152 controls, we studied FokI and BsmI VDR polymorphisms, using the restriction fragment length polymorphism technique.

RESULTS

The FokI polymorphism alleles and genotype were significantly more common in the RA group than in the controls (P=0.001 and P=0.005, respectively). The FokI F allele and F/F genotype were significantly associated with BD (P=0.0003 and P=0.002, respectively). Furthermore, in the group with BD, the FokI polymorphism was significantly associated with the presence of vascular manifestations (P=0.006). In patients with RA, the FokI polymorphism was significantly associated with female gender (P=0.003). No significant associations were found between the Bsm1 polymorphism and RA or BD.

CONCLUSION

The VDR F allele is associated with RA and BD in Tunisians.

Interleukin-19 blockade attenuates collagen-induced arthritis in rats

OBJECTIVES

RA is the most common form of inflammatory arthritis. IL-19 acts as a pro-inflammatory cytokine involved in the pathogenesis of RA. We investigated whether anti-IL-19 antibody treatment would modulate the severity of the disease in a CIA rat model.

METHODS

We generated a CIA model by immunizing rats with bovine type II collagen. CIA rats were s.c. treated with anti-IL-19 antibody 1BB1. The effects of 1BB1 on CIA rats were determined by hind-paw thickness, severity score, bone destruction, BMD and cytokine production, which were evaluated using radiological scans, micro-CT, real-time quantitative PCR and ELISA. To analyse gene regulation by IL-19, rat synovial fibroblasts (SFs) were isolated and analysed for the expression of TNF-α, IL-1β and RANK ligand (RANKL).

RESULTS

In vivo, IL-19 was highly expressed in the synovial tissue and SFs isolated from CIA rats. 1BB1 significantly ameliorated the severity of arthritis by decreasing hind-paw thickness and swelling; prevented bone destruction and bone loss; inhibited the expression of TNF-α, IL-1β, IL-6 and RANKL in synovial tissue; and decreased the production of IL-6 in serum. In vitro, IL-19-induced TNF-α, IL-1β, IL-6 and RANKL expression in CIA SFs.

CONCLUSIONS

Specifically blocking IL-19 inhibited pro-inflammatory cytokine production and prevented bone destruction in CIA rats. These findings provide evidence that IL-19 is a novel target, and that anti-IL-19 antibody may be a potential target to ameliorate the severity of RA.

JNK-1 deficiency limits macrophage-mediated antigen-induced arthritis

OBJECTIVE

To elucidate the nonredundant roles of JNK-1 and JNK-2 in antigen-induced arthritis (AIA).

METHODS

Mice that were genetically disrupted in Jnk1 or Jnk2 were primed by injection of methylated bovine serum albumin (mBSA) in Freund's complete adjuvant and then challenged on day 21 by intraarticular injection of mBSA into the right knee. Bone marrow chimeras were generated and similarly treated. Joints were harvested and prepared for histologic assessment. T cell responses were verified by cytokine and proliferation responses, and relative immunoglobulin responses were measured by enzyme-linked immunosorbent assay. Cytokine messenger RNA expression levels were measured by quantitative polymerase chain reaction analysis. Thioglycollate-elicited and zymosan A-elicited macrophage recruitment was tested in vivo, and cell migration was tested in vitro. The peptide inhibitor D-JNKi was injected daily starting 4 days after intraarticular injection of mBSA into wild-type (WT) mice, and inflammation was scored histologically.

RESULTS

JNK-1-deficient, but not JNK-2-deficient, mice had a reduction in inflammatory cell infiltration and joint damage. This effect was primarily restricted to hematopoietic cells, but B and T cell responses were preserved in mBSA-injected mice. JNK-1-deficient macrophages produced cytokines and chemokines at a level comparable to that in their WT counterparts. However, macrophage migration was impaired in vivo and in vitro. Targeting JNK with the peptide inhibitor D-JNKi dramatically reduced inflammation and joint destruction in WT mice.

CONCLUSION

AIA is dependent on JNK-1, but not JNK-2. JNK-1 is a promising molecular target for reducing autoimmune inflammation, since its inhibition impairs macrophage migration.

Involvement of CX3CL1/CX3CR1 axis in etanercept therapy for patients with active rheumatoid arthritis

Objective

To examine the relationship between serum chemokine levels and patient responsiveness in rheumatoid arthritis (RA) patients to etanercept (ETN) and the influence of ETN administration on serum chemokine levels.

Methods

Serum levels of the chemokines CX3CL1, CXCL8, CXCL10, and CCL3 were quantified prior to (at baseline) and after 14 weeks of treatment with ETN in 20 patients using enzyme-linked immunosorbent assay. Disease status was assessed using the Disease Activity Score (DAS28). The response to ETN was classified according to the European League Against Rheumatism (EULAR) response criteria.

Results

By 14 weeks, ETN produced a significant overall reduction in DAS28 among the 20 patients with RA; eight patients achieved a good response, and 10 patients achieved a moderate response based on EULAR response criteria. A significant reduction in CX3CL1 was observed in the responsive group, although ETN treatment had no significant effect on the serum levels of the other three chemokines. In addition, the messenger ribonucleic acid expression of CX3CR1 in peripheral blood mononuclear cells and the cell-surface expression of CX3CR1 protein in peripheral blood CD8⁺CD3⁺ T cells were both decreased after ETN treatment.

Conclusions

Our results suggest that the CX3CL1 and CX3CR1 in patients with active RA may be sensitive to antitumor necrosis factor-α therapy and confirm that CX3CL1/CX3CR1 axis plays a crucial role in the pathogenesis of RA.

The correlation between increased serum concentrations of interleukin-6 family cytokines and disease activity in rheumatoid arthritis patients

PURPOSE

This study was performed to determine whether the serum concentrations of interleukin (IL)-6 family cytokines are elevated in patients with rheumatoid arthritis (RA) and to investigate the relationship between IL-6 family cytokine levels and disease activity in RA patients.

MATERIALS AND METHODS

We obtained serum samples from 40 patients with RA and 40 age- and sex- matched healthy controls, and we assessed the clinical parameters of disease activity, including the 28-joint disease activity score (DAS28) and C-reactive protein (CRP) levels. Serum samples from five patients with high disease activity (DAS28 > 5.1) were also collected at the eighth week of treatment. Serum concentrations of IL-6, IL-11, and leukemia inhibitory factor (LIF) were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum concentrations of IL-6 family cytokines, including IL-6, IL-11, and LIF, were significantly elevated in patients with RA compared to those of healthy controls. Although there was no significant relationship between IL-6 family cytokine levels and DAS28, the IL-6 levels of patients with RA showed a significant correlation with CRP levels. After eight weeks of medical treatment in patients with high disease activity, a decrease in DAS28 was associated with a significant decrease in the serum concentrations of IL-6 and IL-11.

CONCLUSION

The serum concentrations of IL-6 family cytokines were significantly elevated in patients with RA, and they decreased with medical treatment. These findings suggest a possible role for IL-6 family cytokines in the pathogenesis of RA.

Macrophage migration inhibitory factor: a multifunctional cytokine in rheumatic diseases

Macrophage migration inhibitory factor (MIF) was originally identified in the culture medium of activated T lymphocytes as a soluble factor that inhibited the random migration of macrophages. MIF is now recognized to be a multipotent cytokine involved in the regulation of immune and inflammatory responses. Moreover, the pivotal nature of its involvement highlights the importance of MIF to the pathogenesis of various inflammatory disorders and suggests that blocking MIF may be a useful therapeutic strategy for treating these diseases. This paper discusses the function and expressional regulation of MIF in several rheumatic diseases and related conditions.

The number of elevated cytokines and chemokines in preclinical seropositive rheumatoid arthritis predicts time to diagnosis in an age-dependent manner

OBJECTIVE

To evaluate levels of biomarkers in preclinical rheumatoid arthritis (RA) and to use elevated biomarkers to develop a model for the prediction of time to future diagnosis of seropositive RA.

METHODS

Stored samples obtained from 73 military cases with seropositive RA prior to RA diagnosis and from controls (mean 2.9 samples per case; samples collected a mean of 6.6 years prior to diagnosis) were tested for rheumatoid factor (RF) isotypes, anti-cyclic citrullinated peptide (anti-CCP) antibodies, 14 cytokines and chemokines (by bead-based assay), and C-reactive protein (CRP).

RESULTS

Preclinical positivity for anti-CCP and/or ≥2 RF isotypes was >96% specific for future RA. In preclinical RA, levels of the following were positive in a significantly greater proportion of RA cases versus controls: interleukin-1α (IL-1α), IL-1β, IL-6, IL-10, IL-12p40, IL-12p70, IL-15, fibroblast growth factor 2, flt-3 ligand, tumor necrosis factor α, interferon-γ-inducible 10-kd protein, granulocyte-macrophage colony-stimulating factor, and CRP. Also, increasing numbers of elevated cytokines/chemokines were present in cases nearer to the time of diagnosis. RA patients who were ≥40 years old at diagnosis had a higher proportion of samples positive for cytokines/chemokines 5-10 years prior to diagnosis than did patients who were <40 years old at diagnosis (P < 0.01). In regression modeling using only case samples positive for autoantibodies highly specific for future RA, increasing numbers of cytokines/chemokines were predictive of decreased time to diagnosis, and the predicted time to diagnosis based on cytokines/chemokines was longer in older compared with younger cases.

CONCLUSION

Levels of autoantibodies, cytokines/chemokines, and CRP are elevated in the preclinical period of RA development. In preclinical autoantibody-positive cases, the number of elevated cytokines/chemokines is predictive of the time of diagnosis of future RA in an age-dependent manner.

Interleukin-20 antibody is a potential therapeutic agent for experimental arthritis

OBJECTIVE

Interleukin-20 (IL-20) is a proinflammatory cytokine involved in the pathogenesis of rheumatoid arthritis (RA). We investigated whether anti-IL-20 antibody treatment would modulate the severity of the disease in a collagen-induced arthritis (CIA) rat model.

METHODS

We generated a CIA model by immunizing rats with bovine type II collagen. Rats with CIA were treated subcutaneously with anti-IL-20 antibody 7E, with the tumor necrosis factor (TNF) blocker etanercept, or with 7E in combination with etanercept. Arthritis severity was determined according to the hind paw thickness, arthritis severity score, degree of cartilage damage, bone mineral density, and cytokine production, which were evaluated using radiologic scans, microfocal computed tomography, and enzyme-linked immunosorbent assay. To analyze gene regulation by IL-20, rat synovial fibroblasts (SFs) were isolated and analyzed for the expression of RANKL, IL-17, and TNFα. We also used real-time quantitative polymerase chain reaction analysis and flow cytometry to determine IL-20-regulated RANKL in mouse osteoblastic MC3T3-E1 cells and Th17 cells.

RESULTS

In vivo, treatment with 7E alone or in combination with etanercept significantly reduced the severity of arthritis by decreasing the hind paw thickness and swelling, preventing cartilage damage and bone loss, and reducing the expression of IL-20, IL-1β, IL-6, RANKL, and matrix metalloproteinases (MMPs) in synovial tissue. In vitro, IL-20 induced TNFα expression in SFs from rats with CIA. IL-20 markedly induced RANKL production in SFs, osteoblasts, and Th17 cells.

CONCLUSION

Selectively blocking IL-20 inhibited inflammation and bone loss in rats with CIA. Treatment with 7E combined with etanercept protected rats from CIA better than treatment with etanercept alone. Our findings provide evidence that IL-20 is a novel target and that 7E may be a potential therapeutic agent for RA.

Induction of macrophage migration inhibitory factor in ConA-stimulated rheumatoid arthritis synovial fibroblasts through the P38 map kinase-dependent signaling pathway

BACKGROUND/AIMS

This study was undertaken to identify the intracellular signaling pathway involved in induction of macrophage migration inhibitory factor (MIF) in human rheumatoid arthritis (RA) synovial fibroblasts.

METHODS

Human RA synovial fibroblasts were treated with concanavalin A (ConA), various cytokines, and inhibitors of signal transduction molecules. The production of MIF by synovial fibroblasts was measured in culture supernatants by ELISA. The expression of MIF mRNA was determined using reverse transcriptase polymerase chain reaction (RT-PCR) and real-time PCR. Phosphorylation of p38 mitogen-activated protein (MAP) kinase in synovial fibroblasts was confirmed using Western blotting. The expression of MIF and p38 MAP kinase in RA synovium was determined using dual immunohistochemistry.

RESULTS

The production of MIF by RA synovial fibroblasts increased in a dose-dependent manner after ConA stimulation. MIF was also induced by interferon-γ, CD40 ligand, interleukin-15, interleukin-1β, tumor necrosis factor-α, and transforming growth factor-β. The production of MIF by RA synovial fibroblasts was significantly reduced after inhibition of p38 MAP kinase. The expression of MIF and p38 MAP kinase was upregulated in the RA synovium compared with the osteoarthritis synovium.

CONCLUSIONS

These results suggest that MIF production was induced through a p38 MAP-kinase-dependent pathway in RA synovial fibroblasts.

Lack of TNFR p55 results in heightened expression of IFN-γ and IL-17 during the development of reactive arthritis

Reactive arthritis (ReA) is a type of arthritis originating from certain gastrointestinal or genitourinary infections. In previous studies, we reported the development of progressive Yersinia enterocolitica-induced ReA in mice lacking TNFR p55; however, the mechanisms underlying this effect are still uncertain. In this study, we investigated the impact of TNFR p55 deficiency in modulating Ag-specific Th1 and Th17 responses during this arthritogenic process. We found more severe ReA in TNFRp55(-/-) mice compared with their wild-type (WT) counterparts. This effect was accompanied by increased levels of Yersinia LPS in the joints of knockout mice. Analysis of the local cytokine profile revealed greater amounts of IFN-γ and IL-17 in arthritic joints of TNFRp55(-/-) mice compared with WT mice at day 21 postinfection. Moreover, altered IL-17 and IFN-γ production was observed in mesenteric and inguinal lymph nodes of Yersinia-infected TNFRp55(-/-) mice, as well as in spleen cells obtained from infected mice and restimulated ex vivo with bacterial Ags. Increased levels of cytokine secretion were associated with a greater frequency of CD4(+)IL-17(+), CD4(+)IFN-γ(+), and IL-17(+)IFN-γ(+) cells in TNFRp55(-/-) mice compared with WT mice. Remarkably, Ab-mediated blockade of IL-17 and/or IFN-γ resulted in reduced joint histological scores in TNFRp55(-/-) mice. A mechanistic analysis revealed the involvement of p40, a common subunit of heterodimeric IL-12 and IL-23, in the generation of augmented IFN-γ and IL-17 production under TNFR p55 deficiency. Taken together, these data indicate that, in the absence of TNFR p55 signaling, Th1 and Th17 effector cells may act in concert to sustain the inflammatory response in bacterial-induced arthritogenic processes.

Gene expression profiles of systemic lupus erythematosus and rheumatoid arthritis

Gene expression profiling using microarray technology is being employed to define specific molecular mediators and pathways involved in immunobiology, to understand the intricate interplay of genes participating in the pathogenesis, and to develop biomarkers of disease activity in both systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This review summarizes the latest information on the pathogenesis of SLE and RA and describes the utilization of microarray technology in these systemic autoimmune diseases.

Overexpression of CXC chemokine ligand 14 exacerbates collagen-induced arthritis

CXCL14 is a relatively new chemokine with unidentified receptor and undefined function. Recently, we found that CXCL14 is upregulated in arthritic joints in a mouse model of autoimmune arthritis, collagen-induced arthritis. To examine the role of CXCL14 in the development and pathogenesis of autoimmune arthritis, we have generated transgenic (Tg) mice that overexpress CXCL14 under control of phosphoglycerate kinase promoter. The results showed that CXCL14-Tg mice developed more severe arthritis compared with wild-type controls. The draining lymph nodes of CXCL14-Tg mice were significantly enlarged and contained an increased number of activated T cells, particularly the CD44(+)CD62L(low) effector memory cells. In addition, T cells from CXCL14-Tg mice exhibited an enhanced proliferative response against collagen II and produced higher levels of IFN-gamma but not IL-4 or IL-17. CXCL14-Tg mice also had elevated levels of IgG2a autoantibodies. These findings indicated that CXCL14 plays an important role in the autoimmune arthritis, which may have an implication in understanding the pathogenic mechanisms of rheumatoid arthritis in humans and, ultimately, therapeutic interference.

IFNgamma primes macrophages for inflammatory activation by high molecular weight hyaluronan

The objective was to assess outcomes of IFNgamma-priming upon macrophage activation by the synovial macromolecule high molecular weight hyaluronan [HMW-HA] in the context of rheumatoid arthritis inflammation. Human macrophages primed by IFNgamma and activated by HMW-HA were evaluated for cytokine secretion by ELISA and Milliplex assay and activation profiles by nuclear transcription factor EIA. IFNgamma-primed, HMW-HA-activated macrophages produced elevated levels of TNF and secreted the TH1 cytokine IL-12p70, while IFNgamma suppressed HMW-HA-induced secretion of the regulatory cytokine IL-10 and activation of the transcription factor c-Jun. IFNgamma modulates the HMW-HA-induced cytokine response profile promoting macrophage activation and inflammatory TH1 cytokine secretion.

Angiogenesis in rheumatoid arthritis

Angiogenesis is the formation of new capillaries from pre-existing vessels. A number of soluble and cell-bound factors may stimulate neovascularization. The perpetuation of angiogenesis involving numerous soluble and cell surface-bound mediators has been associated with rheumatoid arthritis (RA). These angiogenic mediators, among others, include growth factors, primarily vascular endothelial growth factor (VEGF) and hypoxia-inducible factors (HIFs), as well as pro-inflammatory cytokines, various chemokines, matrix components, cell adhesion molecules, proteases and others. Among the several potential angiogenesis inhibitors, targeting of VEGF, HIF-1, angiogenic chemokines, tumor necrosis factor-alpha and the alpha(V)beta(3) integrin may attenuate the action of angiogenic mediators and thus synovial angiogenesis. In addition, some naturally produced or synthetic compounds including angiostatin, endostatin, paclitaxel, fumagillin analogues, 2-methoxyestradiol and thalidomide may be included in the management of RA.

New insights in synovial angiogenesis

Angiogenesis is the formation of new capillaries from pre-existing vessels. A number of soluble and cell-bound factors may stimulate neovascularization. The perpetuation of angiogenesis involving numerous soluble and cell surface-bound mediators has been associated with rheumatoid arthritis (RA). These angiogenic mediators, among others, include growth factors, primarily vascular endothelial growth factor (VEGF) and hypoxia-inducible factors (HIFs), as well as pro-inflammatory cytokines, various chemokines, cell adhesion molecules, proteases and others. Among the several potential angiogenesis inhibitors, targeting of VEGF, HIF-1, angiopoietin and the alpha(V)beta(3) integrin, as well as some endogenous or synthetic compounds including angiostatin, endostatin, paclitaxel, fumagillin analogues, 2-methoxyestradiol and thalidomide seems to be promising for the management of synovial inflammation and angiogenesis. A complete review of antiangiogenic drugs used in animal models of arthritis or human RA is available in a table.

Cytokines and cytokine profiles in human autoimmune diseases and animal models of autoimmunity

The precise pathomechanisms of human autoimmune diseases are still poorly understood. However, a deepened understanding of these is urgently needed to improve disease prevention and early detection and guide more specific treatment approaches. In recent years, many new genes and signalling pathways involved in autoimmunity with often overlapping patterns between different disease entities have been detected. Major contributions were made by experiments using DNA microarray technology, which has been used for the analysis of gene expression patterns in chronic inflammatory and autoimmune diseases, among which were rheumatoid arthritis, systemic lupus erythematosus, psoriasis, systemic sclerosis, multiple sclerosis, and type-1 diabetes. In systemic lupus erythematosus, a so-called interferon signature has been identified. In psoriasis, researchers found a particular immune signalling cluster. Moreover the identification of a new subset of inflammatory T cells, so-called Th17 T cells, secreting interleukin (IL)-17 as one of their major cytokines and the identification of the IL-23/IL-17 axis of inflammation regulation, have significantly improved our understanding of autoimmune diseases. Since a plethora of new treatment approaches using antibodies or small molecule inhibitors specifically targeting cytokines, cellular receptors, or signalling mechanisms has emerged in recent years, more individualized treatment for affected patients may be within reach in the future.

BH3-only proteins in rheumatoid arthritis: potential targets for therapeutic intervention

Rheumatoid arthritis (RA) is a debilitating disease, resulting in the destruction of bone and cartilage, and in the permanent disfigurement of joints. Although the precise cause of RA is currently unresolved, it has become clear that the damaging effects are a result of the toxic milieu caused by an influx of inflammatory cells and the resulting heightened proinflammatory state within the joint. As the amount of literature suggesting that this preponderance of cells is a result of decreased local apoptosis in the joint continues to increase, in this review, we describe how Bcl-2 family pro-apoptotic BH3-only proteins, particularly Bim and Bid, could act to protect against the development of the disease. We also suggest a role for BH3-mimetic drugs as potential therapeutics in the treatment of RA.

Impact of IL-32 on Histamine Release by Human Derived Umbilical Cord Blood Mast Cells

IL-32 is onae of the last important cytokines discovered, produced mainly by T cells, natural killer cells, and epithelial cells. Probably many other different cells are a source of IL-32, which has been found to be a powerful pro-inflammatory mediator. Here we studied the effect of IL-32 on histamine release by human-derived cord-blood mast cells. In these studies we found that IL-32 significantly stimulates the release of histamine only at high concentrations (100 ng/ml) while at 10 or 50 ng/ml it had no effect. These results were found for the first time and demonstrate that IL-32 may play an important role in allergic and inflammatory diseases.

Angiogenesis and its targeting in rheumatoid arthritis

Angiogenesis, the development of new capillaries, is involved in leukocyte ingress into the synovium during the development and progression of rheumatoid arthritis. Several soluble and cell surface-bound mediators including growth factors, cytokines, chemokines, proteolytic matrix-degrading enzymes, cell adhesion molecules and others may promote synovial neovascularization. On the other hand, endogenous angiostatic factors, such as angiostatin, endostatin, interleukin-4 (IL-4), IL-13, interferons and some angiostatic chemokines are also produced within the rheumatoid synovium, however, their effects are insufficient to control synovial angiogenesis and inflammation. Several specific and non-specific strategies have been developed to block the action of angiogenic mediators. The first line of angiostatic agents include vascular endothelial growth factor (VEGF), angiopoietin, alpha(V)beta(3) integrin antagonist, as well as non-specific angiogenesis inhibitors including traditional disease-modifying agents (DMARDs), anti-tumor necrosis factor biologics, angiostatin, endostatin, fumagillin analogues or thalidomide. Potentially any angiostatic compound could be introduced to studies using animal models of arthritis or even to human rheumatoid arthritis trials.

Involvement of Th17 cells and the effect of anti-IL-6 therapy in autoimmune uveitis

OBJECTIVES

Human endogenous uveitis is one of the sight-threatening diseases associated with variety of systemic disorders, such as Behcet's disease and sarcoidosis. Recently, biosynthesized antibodies against inflammatory cytokines have been recognized to be useful to control the regional inflammation. In this study, we focused on the possibility of IL-6-based biological therapies for endogenous uveitis. We initially confirmed the significant increase of several inflammatory soluble factors including IL-6 in the vitreous fluids from refractory/chronic engogenous uveitis patients.

METHODS

To investigate the role of IL-6 in the formation of refractory ocular inflammation, we used the mouse experimental autoimmune uveitis (EAU) model. Both IL-6 and IL-23 are required for the development of IL-17-producing helper T subset (Th17) from naïve CD4(+) T cells. Results. In the EAU model, neither IL-6-deficient mice nor IL-23-deficient mice could induce Th17 cells and the EAU score was decreased in these mice in the entire time course. We also confirmed that systemic administration of anti-il-6 receptor antibody ameliorates EAU By suppressing both systemic and regional TH17 responses.

CONCLUSIONS

IL-6 is responsible for causing ocular inflammation, and it is, at least partially, due to IL-6-dependent Th17 differentiation. IL-6 may be a target for therapy of refractory endogenous uveitis in humans.

Vascular involvement in rheumatic diseases: 'vascular rheumatology'

The vasculature plays a crucial role in inflammation, angiogenesis, and atherosclerosis associated with the pathogenesis of inflammatory rheumatic diseases, hence the term 'vascular rheumatology'. The endothelium lining the blood vessels becomes activated during the inflammatory process, resulting in the production of several mediators, the expression of endothelial adhesion molecules, and increased vascular permeability (leakage). All of this enables the extravasation of inflammatory cells into the interstitial matrix. The endothelial adhesion and transendothelial migration of leukocytes is a well-regulated sequence of events that involves many adhesion molecules and chemokines. Primarily selectins, integrins, and members of the immunoglobulin family of adhesion receptors are involved in leukocyte 'tethering', 'rolling', activation, and transmigration. There is a perpetuation of angiogenesis, the formation of new capillaries from pre-existing vessels, as well as that of vasculogenesis, the generation of new blood vessels in arthritis and connective tissue diseases. Several soluble and cell-bound angiogenic mediators produced mainly by monocytes/macrophages and endothelial cells stimulate neovascularization. On the other hand, endogenous angiogenesis inhibitors and exogenously administered angiostatic compounds may downregulate the process of capillary formation. Rheumatoid arthritis as well as systemic lupus erythematosus, scleroderma, the antiphospholipid syndrome, and systemic vasculitides have been associated with accelerated atherosclerosis and high cardiovascular risk leading to increased mortality. Apart from traditional risk factors such as smoking, obesity, hypertension, dyslipidemia, and diabetes, inflammatory risk factors, including C-reactive protein, homocysteine, folate deficiency, lipoprotein (a), anti-phospholipid antibodies, antibodies to oxidized low-density lipoprotein, and heat shock proteins, are all involved in atherosclerosis underlying inflammatory rheumatic diseases. Targeting of adhesion molecules, chemokines, and angiogenesis by administering nonspecific immunosuppressive drugs as well as monoclonal antibodies or small molecular compounds inhibiting the action of a single mediator may control inflammation and prevent tissue destruction. Vasoprotective agents may help to prevent premature atherosclerosis and cardiovascular disease.

Anti-cyclic citrullinated peptide antibodies and IL-23p19 in psoriatic arthritis

BACKGROUND

Anti-cyclic citrullinated peptide antibodies (anti-CCP) are reported to be found in 5-13% of patients with psoriatic arthritis (PsA). However, whether anti-CCP-positive PsA patients and rheumatoid arthritis (RA) patients have a similar pathophysiological background still remains uncertain.

OBJECTIVE

To determine the prevalence of anti-CCP antibodies in patients with PsA and characterize these anti-CCP-positive patients of PsA.

METHODS

We measured the serum levels of the anti-CCP antibodies in patients with PsA (n=16), psoriasis (n=15), RA (n=9) and healthy controls (n=11). Serum levels of rheumatoid factor (RF), matrix metalloproteinase-3 (MMP-3), cartilage oligomeric matrix protein (COMP), interleukin (IL)-23p19 and IL-12p40 were also measured in all the samples.

RESULTS

Two of the 16 PsA patients (13%) were positive for anti-CCP antibodies with high titers of RF. However, the serum IL-23p19 levels were two orders of magnitude higher in the anti-CCP-positive PsA patients as compared with those in the RA patients and anti-CCP-negative PsA patients. No significant elevation of the serum levels of MMP-3, COMP and IL-12p40 was found in these patients.

CONCLUSION

Thirteen percent of the PsA patients were positive for anti-CCP. These patients do not fulfill the American College of Rheumatology (ACR) classification criteria for RA so far. Furthermore, they showed the typical clinical features of PsA rather than those of RA. Although anti-CCP-positive PsA patients may possibly be have a risk of developing RA, we propose that these patients be classified, for the moment, into a independent subtype of PsA, as a different entity from RA.

Exacerbation of autoimmune arthritis by copolymer-I through promoting type 1 immune response and autoantibody production

Copolymer-I (COP-I) is an unique immune regulatory polymer that has been shown to suppress experimental autoimmune encephalomyelitis (EAE) and is a treatment option for multiple sclerosis (MS). To investigate whether its immune suppressive effects can be extended to other autoimmune diseases, we treated mice with COP-I during the induction of collagen-induced arthritis (CIA). Our results show that COP-I treatment exacerbated CIA, leading to faster onset, more severe and longer-lasting disease. The mechanisms underlying the exacerbation of CIA by COP-I treatment include enhanced activation and inflammatory cytokine production by autoreactive T cells and elevated production of autoreactive antibodies. In addition, germinal center response was significantly enhanced by COP-I treatment. Thus, great caution should be taken when COP-I is to be used in MS patients with other autoimmune complications or its potential therapeutic effects are to be extended beyond autoimmune demyelinating diseases.