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ID PMID Title PublicationDate abstract
22819087 Tight disease control in early RA. 2012 May The past decade has brought increasing evidence to support aggressive therapeutic intervention in early rheumatoid arthritis (RA). Treat-to-target strategies that focus on frequent monitoring and treatment adjustments to achieve states of low disease activity or clinical remission have shown superior long-term results. Both oral disease-modifying antirheumatic drugs and biologic agents are effective in treating early RA. It remains unclear if initial combination therapy or biologic use is more effective in early active disease as compared with the traditional approach. The authors review various studies on the treatment of early RA with a focus on studies with a treat-to-target approach.
22298075 [ Bone and cartilage destruction in RA and its intervention. Disease-modifying antirheumat 2012 Feb The primary goal in the treatment of rheumatoid arthritis (RA) is to maintain good quality of life by preventing joint destruction and avoiding disability. For this purpose, all patients with the diagnosis of RA should be treated by disease-modifying antirheumatic drugs (DMARDs) including biologic DMARDs and non-biologic DMARDs. All DMARDs are expected to prevent the progression of bone and cartilage destruction of RA patients from the results of in vitro research, and prevention of joint destruction is confirmed in vivo in all biologic DMARDs, but not in all non-biologic DMARDs. In this chapter, we would like to review the results of basic researches and clinical studies to demonstrate the prevention of joint destruction by non-biologic DMARDs that have been frequently used I daily practice.
23103807 [Osteoimmunology-overview]. 2012 Nov The immune and skeletal systems are closely related through a number of shared regulatory molecules including cytokines. Studies on bone destruction associated rheumatoid arthritis (RA) as well as identification of the various bone phenotypes found in immune-compromised genetically modified mice have highlighted the importance of the interplay between the two systems, and promoted the new interdisciplinary field of "osteoimmunology" . Accumulating evidence has indicated that bone destruction associated with RA is caused by the enhanced activity of osteoclasts, resulting from the activation of a unique helper T cell subset, "Th17 cells" . The osteoimmunological insight is of growing importance in clinical applications. Furthermore, recent studies has suggested the relationship between bone cells and hematopoietic stem cells in bone marrow. Various cell types in bone marrow are expected to control bone homeostasis, calcium metabolism and hematopoiesis by mutually affecting each other. Osteoimmunology becomes the viewpoint indispensable for not only bone and mineral research but also immunological research.
21497534 Remission in early rheumatoid arthritis treated with conventional DMARDs. Results of a two 2012 Jan OBJECTIVE: This study aimed to evaluate remission in patients with early RA treated by conventional DMARDs and to identify its possible predictor factors. METHODS: Patients with early RA (<12 months) were enrolled in a 2-year follow-up study. Standard evaluation completed at baseline and at 24 months included clinical, laboratory, functional and structural assessment. Clinical remission after 2 years of follow-up was defined when DAS28 was less than 2.6. Possible predictor factors for remission were analyzed. RESULTS: Fifty-one patients (88.2% women, mean age of 46.9 [24-72] years, mean disease duration of 24 [6-48] weeks) were enrolled in this study. The delay in referral for specialist care was 140 [7-420] days. Rheumatoid factor, anti-CCP, HLA-DRB1*01 and DRB1*04 alleles were present respectively in 62.5, 56.6, 11.8, and 45.1% of patients. At 24 months, 77.2% received a median dose of 5 (0-8) mg/day of prednisone and 65.2% was taking methotrexate (MTX). 13.6% of patients had stopped their DMARD because of socioeconomic difficulties. At 24 months, we noted a significant improvement of morning stiffness, pain score, swollen joint count, ESR, CRP, DAS28 and HAQ scores. Remission at 2 years was noted in 34.8% of patients and was significantly associated in univariate but not in multivariate analysis to male sex (P=0.02) and to short delay in referral for specialist (P=0.03). CONCLUSION: In this cohort of early RA patients treated with conventional DMARDs, especially with methotrexate in monotherapy, remission at 2-year of follow-up was obtained in one third of patients. No predictor factors of remission were found out. These results should be verified by further studies.
21249408 Assessment of cervical pain and function in patients with rheumatoid arthritis. 2011 Jun Rheumatoid arthritis (RA) is characterized by inflammation of the synovial membrane, which can lead to deformities and functional disability. Unlike the dorsal and lumbar spine, the cervical spine is often affected by RA. The objective of this paper is to assess cervical pain and function in patients with RA and correlate these variables with overall function, quality of life, and radiographic findings on the cervical spine. One hundred individuals aged 18 to 65 years were divided into study group (50 patients with rheumatoid arthritis) and control group (50 healthy individuals, paired for gender and age). Patients with prior surgery, prior trauma or other symptomatic cervical spine condition were excluded. The visual analogue pain scale (VAS), Neck Pain and Disability Scale (NPDS), SF-36, HAQ and X-rays were used for evaluation purposes. Mean disease duration was 11.1 years. The cervical VAS was 2.4 cm and 1.3 cm for the study and control groups, respectively (p = 0.074). Statistical differences were found in NPDS scores, mean = 26.7 and 6.9, and HAQ scores, mean = 1.1 and 0.1, for the study and control groups, respectively (p < 0.001). SF-36 scores were statistically worse in the study group, except for the vitality, social aspects and mental health subscales. There was a positive correlation between the NPDS and VAS (r = 0.54) and between the NPDS and HAQ (r = 0.67). There was a negative correlation between the NPDS and SF-36 functional capacity domain (r = -0.53) and physical limitation domain (r = -0.58). The radiographic findings revealed more prevalent anterior atlanto-axial subluxation (p = 0.030), listhesis in neutral posture (p = 0.037), listhesis in extension (p = 0.007), degenerative alteration of C4-C5 segment (p = 0.023), size of C2 spinal canal (p = 0.002) and C3 spinal canal (p = 0.029) in the study group. Patients with RA have poorer cervical function than healthy individuals, although there is no difference in cervical pain.
21905018 Soluble VE-cadherin in rheumatoid arthritis patients correlates with disease activity: evi 2012 Jan OBJECTIVE: Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder that principally attacks synovial joints. However, accelerated atherosclerosis and increased cardiovascular morbidity and mortality are major clinical consequences of endothelial dysfunction in RA patients. Tumor necrosis factor α (TNFα) is the major mediator of inflammation in RA, related to vascular injury by targeting VE-cadherin, an endothelium-specific adhesion molecule of vital importance for endothelium integrity and angiogenesis. We undertook this study to examine the mechanisms regulating VE-cadherin processing by TNFα and their occurrence in RA. METHODS: Human umbilical vein endothelial cells were used in primary culture and treated with recombinant TNFα to study VE-cadherin cleavage. Cell lysates and conditioned media were analyzed by Western blotting for VE-cadherin cytoplasmic domain and extracellular domain (VE-90) generation, respectively. VE-90 was analyzed at baseline and at the 1-year followup in sera from 63 RA patients (from the Very Early Rheumatoid Arthritis cohort) with disease duration of <6 months. RESULTS: TNFα induced a time-dependent shedding of VE-90 in cell media. This effect was prevented by tyrosine kinase inhibitors (genistein and PP2) or by knocking down Src kinase. In contrast, tyrosine phosphatase blockade enhanced VE-cadherin cleavage, confirming the requirement of tyrosine phosphorylation processes. In addition, using the matrix metalloproteinase (MMP) activator APMA and the MMP inhibitor GM6001, we demonstrated that MMPs are involved in TNFα-induced VE-cadherin cleavage. Of major importance, VE-90 was detected in sera from the 63 RA patients and was positively correlated with the Disease Activity Score at baseline and after 1-year followup. CONCLUSION: These findings provide the first evidence of VE-cadherin proteolysis upon TNFα stimulation and suggest potential clinical relevance of soluble VE-cadherin in management of RA.
21536151 Anti-TNFα discontinuation in rheumatoid and psoriatic arthritis: is it possible after dis 2011 Aug Anti-TNFα blockers have rapidly become a standard treatment for rheumatoid (RA) and psoriatic arthritis (PsA) because of their acceptable safety profile and efficacy. Clinical and radiological remission may now be a realistic outcome and constitutes the best achievable state. However, clinical practice guidelines and consensus statements on the criteria of introduction, duration and cessation of treatment are under constant revision. Evidence supports that the early use of biologic DMARDs would produce rapid and sustained suppression of inflammatory disease and preserve function and joint erosions. Proof of this concept, anti-TNFα agents would be effective in maintaining response after cessation of treatment. Conversely, when therapy with anti-TNFα is withdrawn, the disease rapidly returns. Remission may be defined as minimal or no clinically detectable disease activity in the presence of continuing drug treatment and a rapid control of disease activity may prevent irreversible damage and disability. The use of US-PD and MRI in the early detection of disease recurrence could become necessary to prevent the relapse and direct the clinician's choice concerning a re-treatment regimen. The use of biological treatment can be for a limited period, at a time when it has the greatest opportunity to make the difference.
22640912 Nanomedicines for chronic non-infectious arthritis: the clinician's perspective. 2012 Sep Rheumatoid arthritis (RA) and osteoarthritis (OA) are prevalent chronic health conditions. However, despite recent advances in medical therapeutics, their treatment still represents an unmet medical need because of safety and efficacy concerns with currently prescribed drugs. Accordingly, there is an urgent need to develop and test new drugs for RA and OA that selectively target inflamed joints thereby mitigating damage to healthy tissues. Conceivably, biocompatible, biodegradable, disease-modifying antirheumatic nanomedicines (DMARNs) could represent a promising therapeutic approach for RA and OA. To this end, the unique physicochemical properties of drug-loaded nanocarriers coupled with pathophysiological characteristics of inflamed joints amplify bioavailability and bioactivity of DMARNs and promote their selective targeting to inflamed joints. This, in turn, minimizes the amount of drug required to control articular inflammation and circumvents collateral damage to healthy tissues. Thus, nanomedicine could provide selective control both in space and time of the inflammatory process in affected joints. However, bringing safe and efficacious DMARNs for RA and OA to the marketplace is challenging because regulatory agencies have no official definition of nanotechnology, and rules and definitions for nanomedicines are still being developed. Although existing toxicology tests may be adequate for most DMARNs, as new toxicity risks and adverse health effects derived from novel nanomaterials with intended use in humans are identified, additional toxicology tests would be required. Hence, we propose that detailed pre-clinical in vivo safety assessment of promising DMARNs leads for RA and OA, including risks to the general population, must be conducted before clinical trials begin.
21383200 Inflammation-dependent secretion and splicing of IL-32{gamma} in rheumatoid arthritis. 2011 Mar 22 Different splice variants of the proinflammatory cytokine IL-32 are found in various tissues; their putative differences in biological function remain unknown. In the present study, we report that IL-32γ is the most active isoform of the cytokine. Splicing to one less active IL-32β appears to be a salvage mechanism to reduce inflammation. Adenoviral overexpression of IL-32γ (AdIL-32γ) resulted in exclusion of the IL-32γ-specific exon in vitro as well as in vivo, primarily leading to expression of IL-32β mRNA and protein. Splicing of the IL-32γ-specific exon was prevented by single-nucleotide mutation, which blocked recognition of the splice site by the spliceosome. Overexpression of splice-resistant IL-32γ in THP1 cells or rheumatoid arthritis (RA) synovial fibroblasts resulted in a greater induction of proinflammatory cytokines such as IL-1β, compared with IL-32β. Intraarticular introduction of IL-32γ in mice resulted in joint inflammation and induction of several mediators associated with joint destruction. In RA synovial fibroblasts, overexpression of primarily IL-32β showed minimal secretion and reduced cytokine production. In contrast, overexpression of splice-resistant IL-32γ in RA synovial fibroblasts exhibited marked secretion of IL-32γ. In RA, we observed increased IL-32γ expression compared with osteoarthritis synovial tissue. Furthermore, expression of TNFα and IL-6 correlated significantly with IL-32γ expression in RA, whereas this was not observed for IL-32β. These data reveal that naturally occurring IL-32γ can be spliced into IL-32β, which is a less potent proinflammatory mediator. Splicing of IL-32γ into IL-32β is a safety switch in controlling the effects of IL-32γ and thereby reduces chronic inflammation.
21732014 KRN/I-Ag7 mouse arthritis is independent of complement C3. 2011 Oct BACKGROUND: KRN/I-A(g7) (KxB/N) is a mouse model of inflammatory arthritis, which resembles human rheumatoid arthritis. Arthritis in these animals is caused by autoreactivity to a ubiquitously expressed autoantigen, glucose-6 phosphate isomerase. Tolerance is broken at both the T cell and B cell level. The sera from KRN/I-A(g7) mice can induce mouse arthritis in healthy mice. Complement components of the alternative complement pathway, including C3, have been shown to be required in induction of mouse arthritis by serum transfer. METHODS: We have bred KRN/I-A(g7) mice onto a C3-deficient background and followed cohorts for the spontaneous appearance of arthritis. We have also transferred KxB/N serum to B6.I-A ( g7 ) recipients. RESULTS: C3-deficient KRN/I-A(g7) mice spontaneously developed severe, destructive arthritis, comparable to that seen in C3-intact KRN/I-A(g7) mice. However, serum transfer experiments confirmed the strong requirement for C3 in the passive model. CONCLUSION: The pathogenesis of spontaneous KRN/I-A(g7) arthritis can largely proceed by complement-independent pathways and must have pathology effector mechanisms in addition to those seen in the passive serum transfer model.
22073935 Biologic agents in rheumatoid arthritis: an update for managed care professionals. 2011 Nov BACKGROUND: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory arthritis that clinically manifests as joint pain, stiffness, and swelling. If left untreated, persistent synovial inflammation can progress to cartilage and bone destruction and ultimately to major long-term disability and mortality. Synthetic disease-modifying antirheumatic drugs (DMARDs), such as methotrexate, leflunomide, and sulfasalazine, have markedly improved clinical symptoms and slowed joint damage in RA patients. However, despite the effectiveness of synthetic DMARDs, many patients who use them continue to have clinical symptoms of inflammation and progressive joint destruction. Recent advances in our understanding of the pathogenesis of RA have led to the identification of novel cellular and molecular therapeutic targets. Biologic agents aimed at these targets have provided some evidence of effectiveness that is transforming the management of RA. OBJECTIVE: To inform health care providers about some of the recent advances in RA pathogenesis and innovative biologic therapies that have shown effectiveness in improving clinical outcomes and inhibiting radiographic progression. SUMMARY: Although the specific trigger of the autoimmune response in RA is not known, pathogenesis is generally believed to be associated with the generation of autoantibodies through interactions of antigen-presenting cells with the adaptive immune system (CD4 + T cells and B cells). The main inflammatory mediators of joint inflammation and destruction in RA are tumor necrosis factor (TNF)-alpha, interleukin-1 (IL-1), IL-6, chemokines, and proteases. Advances in our understanding of the key cells and inflammatory cytokines have led to the development of targeted biologic agents. As of 2011, 5 TNF-alpha inhibitors are approved for use by the FDA: infliximab, etanercept, adalimumab, golimumab, and certolizumab pegol. In randomized clinical trials, all of these agents have been shown to be effective in reducing clinical signs of inflammation in RA patients who have failed synthetic DMARDs. Multiple studies have demonstrated significant benefits of early treatment with TNF-alpha inhibitors combined with methotrexate. Other FDA-approved biologic agents for treating moderate-to-severe RA include abatacept, rituximab, and tocilizumab. All biologic agents carry an increased risk of infections. Additional potential side effects include infusion and injection site reactions for intravenous and subcutaneously administered agents, respectively. All patients being considered for biologic agents should be screened annually for tuberculosis and should receive pneumococcal, influenza, and hepatitis B vaccinations.
22475245 The effect of tumor necrosis factor-α antagonists on arterial stiffness in rheumatoid art 2012 Aug BACKGROUND: There is evidence that patients with rheumatoid arthritis (RA) have a higher arterial stiffness than their age-matched healthy counterparts and thus have a higher cardiovascular risk. Under National Institute for Clinical Excellence guidelines, tumor necrosis factor-α (TNF-α) antagonists are indicated clinically in patients with severe active rheumatoid disease. TNF-α antagonists have been found to reduce inflammatory markers in RA; however, it is debatable if they have favorable effects on the cardiovascular system. This review evaluates the effect of TNF-α antagonists on arterial stiffness, a predictor of cardiovascular disease, in RA patients. SEARCH STRATEGY: A search of Ovid MEDLINE and ISI Web of Knowledge databases was conducted to identify studies into the effect of TNF-α antagonists on arterial stiffness in RA patients. Eight studies matching the search criteria were included for analysis. FINDINGS: Two methods were used to assess arterial stiffness: pulse wave velocity and augmentation index. Despite inconsistencies in augmentation index values, aortic pulse wave velocity in all but one study was significantly reduced following TNF-α antagonist treatment. Most studies had methodological limitations, including inadequate sample size, nonblinding of those involved in the measurements, and inadequate inclusion/exclusion criteria. Variation in results could be due to the use of different TNF-α antagonists, different outcome measures being used, and differences in follow-up. CONCLUSIONS: The balance of evidence suggests that TNF-α antagonists may have a beneficial effect on arterial stiffness and therefore cardiovascular risk. However, larger more robust longer term studies are warranted to confirm recent findings.
23117244 Healthcare service utilisation costs are reduced when rheumatoid arthritis patients achiev 2013 Oct OBJECTIVE: Determine healthcare service utilisation costs among patients using biological therapies for rheumatoid arthritis (RA), considering the magnitude and duration of patient response achieved. METHODS: Clinical data from the Alberta Biologics Pharmacosurveillance Program (ABioPharm) was linked with provincial physician billing claims, outpatient visits and hospitalisations. The annual mean healthcare service utilisation costs (total, RA-attributable, non-RA attributable) were estimated for patients during the best disease activity level reached during treatment. RESULTS: Of 1086 patients: 16% achieved DAS28 remission >1 year, 37% had a DAS28 remission period <1 year, 13% had a low disease activity (LDA) period <1 year and 31% had persistent moderate or high disease activity. Mean annual healthcare service utilisation cost savings for those in sustained remission was $2391 (95% CI 1437 to 3909, p<0.001) and $2104 (95% CI 838 to 3512, p<0.001) for those with non-sustained LDA, relative to the persistent disease activity group. Savings were also observed for those in sustained remission compared to non-sustained remission (annual savings $1422, 95% CI 564 to 2796, p<0.001). RA-related costs were consistent across disease activity and cost categories; the majority of costs were attributable to non-RA related hospitalisations. CONCLUSIONS: We provide evidence of economic benefits to the healthcare system when RA patients achieve persistent good disease control. Benefits from brief periods of remission and LDA are also observed. Coupled with an expected increase in productivity from improved disease control, there is societal benefit to the utilisation of biologics in RA management to achieve treatment goals.
22910193 Prevalence of antiphospholipid antibodies in rheumatoid arthritis patients and relationshi 2012 INTRODUCTION: It is still unclear how important the presence of antiphospholipid antibodies (aPL) is in patients with rheumatoid arthritis (RA). OBJECTIVES: The aim of the study was to assess the prevalence of selected aPL in RA patients and their correlation with the presence of markers for RA antibodies and with disease activity. PATIENTS AND METHODS: The study group consisted of 97 patients with RA who had never been treated with biological agents. In all patients, serum anticardiolipin antibodies (aCL), anti‑β2‑glycoprotein I antibodies (a‑β2‑GPI), lupus anticoagulant (LAC), immunoglobulin M (IgM) rheumatoid factor (RF), and anticyclic citrullinated peptide antibodies (anti‑CCP) were measured and disease activity was assessed. RESULTS: The presence of aPL was observed in 27 patients (27.8%): aCL in 20 patients (20.6%), a‑β2‑GPI in 12 patients (12.4%), and LAC in 1 patient (1%). Positive aCL of low or medium levels were detected in the IgM class in 11 patients (11.3%) and in the IgG class in 12 patients (12.5%). Positive a‑β2‑GPI of low and medium levels were found only in the IgM class. The presence of LAC was associated with aCL‑IgM and a‑β2‑GPI‑IgM. A significant correlation was observed between the presence of anti‑CCP and different types of aPL. There was no correlation between aPL and IgM‑RF or disease activity markers. CONCLUSIONS: The prevalence of aPL in patients with RA is relatively high. There is a relationship between the prevalence of aPL and anti‑CCP-serological marker of RA, but there are no significant correlations between disease activity and the presence of aPL.
21861866 Lymphotoxin α revisited: general features and implications in rheumatoid arthritis. 2011 Jul 26 Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting synovial joints. Therapies blocking tumor necrosis factor-alpha (TNFα) are now routinely used in the management of RA. However, a significant number of patients with RA do not respond or develop resistance to anti-TNF therapies, and the participation of other cytokines in RA pathogenesis has been reported as well. Lymphotoxin alpha (LTα) is the closest homolog to TNFα and has been implicated in inflammation and autoimmunity since its original description in 1968. In spite of that, little is known about the role of LTα in RA or the potential of blocking this cytokine as an alternative therapeutic approach. In this review, we aim to summarize the general features of LTα and what is currently known about its participation in RA.
22249375 Potential of the HAQ score as clinical indicator suggesting comprehensive multidisciplinar 2012 May This study explores the potential of the health assessment questionnaire (HAQ) score as a clinical indicator that can be used to suggest comprehensive multidisciplinary assessments, by relating it to more general aspects of disability. In a cohort of 132 patients with early RA (mean age 55, 68% women), 28 joint count Disease Activity Scores (DAS-28), HAQ, and Short Form 36 (SF-36) scores were registered at annual follow-up visits 8 years after diagnosis. The patients were tentatively sub-grouped into a high-HAQ group (HAQ ≥ 1 at the 8-year follow-up) and a low-HAQ group. The high-HAQ group, comprising 36% of the cohort, had a higher mean HAQ score at inclusion and beyond at all visits compared to the low-HAQ group, and 24% of all individual patients in the high-HAQ group had a HAQ score ≥ 1 at inclusion. Although the DAS-28 improved in both groups, patients in the high-HAQ group also had significantly more persistent disability according to the SF-36: five scales at each follow-up visit and all eight scales at the majority of the visits. Individual RA patients with HAQ ≥ 1 probably have considerable persistent disabilities according to the SF-36. The HAQ score could be used as a clinical indicator suggesting comprehensive multidisciplinary assessments of the components of disability and corresponding interventions, in addition to the established use of HAQ at group levels and in parallel with the medication strategy based on DAS-28.
22499425 Infection and immune-mediated meningococcal-associated arthritis: combination features in 2012 Mar We present a case of a 16-year-old male patient with sudden-onset, rash, arthritis and meningitis by Neisseria meningitidis one week after an acute upper respiratory infection. On the 10th day of treatment followed by neurological and arthritis clinical improvement, he presented once again a tender and swollen left knee with a moderate effusion, and active and passive range of motion was severely limited secondary to pain, and when he was submitted to surgical drainage and synovial fluid analysis he showed inflammatory characteristics. A non-steroidal anti-inflammatory drug was taken for five days with complete improvement of symptoms. The case is notable for its combination of features of septic and immune-mediated arthritis, which has rarely been reported in the same patient.
23135058 Rheumatoid nodule presenting as Morton's neuroma. 2013 Sep Among 101 feet that presented with symptoms and signs similar to Morton's neuroma, intermetatarsal rheumatoid nodules were found in five feet (three patients). Two patients had bilateral involvement. Histology of the excised tissue showed the presence of a rheumatoid nodule and Morton's neuroma in four feet and a rheumatoid nodule with unremarkable nerve bundles in one. A rheumatoid nodule can coexist with Morton's neuroma, as seen in our patients, and the presentation is often similar to that of a Morton's neuroma. Our patients were rendered asymptomatic with surgical treatment and went on to have appropriate management of rheumatoid arthritis. Rheumatoid nodule should be considered in the differential diagnosis of Morton's neuroma in not only rheumatoid arthritis patients but also asymptomatic patients who have never been tested for rheumatoid antibodies.
21751570 The role of anti-cyclic citrullinated peptide antibodies in predicting rheumatoid arthriti 2011 The study presents the results of predicting role of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis, compared to rheumatoid factor. 32 patients with rheumatoid arthritis were identified from a retrospective chart review. The results of our study show that presence of the rheumatoid factor has less diagnostic and prognostic significance than the anti-cyclic citrullinated peptide, and suggests its superiority in predicting an erosive disease course.
20238216 FK506 inhibition of gliostatin/thymidine phosphorylase production induced by tumor necrosi 2011 Jul Gliostatin/thymidine phosphorylase (GLS/TP) is known to have angiogenic and arthritogenic activities. The purpose of this study was to determine the inhibitory effects of FK506 (tacrolimus) on GLS production in rheumatoid arthritis (RA). We investigated the modulation of serum GLS by FK506 therapy and the effect of FK506 on the production of GLS in fibroblast-like synoviocytes (FLSs). Serum samples were collected from 11 RA patients with active disease at baseline and after 12 weeks of FK506 treatment. Serum concentrations of GLS and matrix metalloproteinase (MMP)-3 were measured by ELISA and found to be down-regulated in responders evaluated with a disease activity score. Patient FLSs were cultured and stimulated by tumor necrosis factor (TNF)-α with or without FK506. The expression levels of GLS were determined using reverse transcription-polymerase chain reaction (RT-PCR) and enzyme immunoassay and shown to be significantly increased. GLS levels in TNF-α-stimulated FLSs were reduced by FK506 treatment. Our data show a novel mechanism for the action of physiological concentrations of FK506 in RA that regulates the production of GLS in FLSs.