Chondroprotective effects of CDK4/6 inhibition via enhanced ubiquitin-dependent degradation of JUN in synovial fibroblasts.

OBJECTIVE: Targeting synovial fibroblasts (SF) using a cyclin-dependent kinase (CDK) 4/6 inhibitor (CDKI) could be a potent therapy for RA via inhibition of proliferation and MMP-3 production. This study was designed to elucidate the mechanism of chondroprotective effects on SFs by CDK 4/6 inhibition. METHODS: CDK4/6 activity was inhibited using CDKI treatment or enhanced by adenoviral gene transduction. Chondroprotective effects were evaluated using a collagen-induced arthritis model (CIA). Gene and protein expression were evaluated with quantitative PCR, ELISA and Western blotting. The binding of nuclear extracts to DNA was assessed with an electrophoresis mobility shift assay. RNA-Seq was performed to identify gene sets affected by CDKI treatment. RESULTS: CDKI attenuated cartilage destruction and MMP-3 production in CIA. In RASFs, CDKI impaired the binding of AP-1 components to DNA and inhibited the production of MMP-1 and MMP-3, which contain the AP-1 binding sequence in their promoter. CDK4/6 protected JUN from proteasome-dependent degradation by inhibiting ubiquitination. The RNA-Seq analysis identified CDKI-sensitive inflammatory genes, which were associated with the pathway of RA-associated genes, cytokine-cytokine receptor interaction and IL-17 signalling. Notably, the AP-1 motif was enriched in these genes. CONCLUSION: The mechanism of chondroprotective effects by CDK4/6 inhibition was achieved by the attenuation of AP-1 transcriptional activity via the impaired stability of JUN. Because the pharmacologic inhibition of CDK4/6 has been established as tolerable in cancer treatment, it could also be beneficial in patients with RA due to its chondroprotective and anti-inflammatory effects.

Branched chain amino acids in the treatment of polymyositis and dermatomyositis: a phase II/III, multi-centre, randomized controlled trial.

OBJECTIVES: To assess the efficacy and safety of branched chain amino acids (BCAAs) in the treatment of PM/DM prior to official approval of their use in Japan. METHODS: Treatment naïve adults with PM/DM were enrolled in a randomized, double-blind trial to receive either TK-98 (drug name of BCAAs) or placebo in addition to conventional treatment. After 12 weeks, patients with an average manual muscle test (MMT) score <9.5 were enrolled in an open label extension study for a further 12 weeks. The primary endpoint was the change of the MMT score at 12 weeks. The secondary endpoints were the clinical response and the change of functional index (FI). RESULTS: Forty-seven patients were randomized either to the TK-98 (n = 24) or placebo (n = 23) group. The changes of MMT scores at 12 weeks were 0.70 (0.19) [mean (s.e.m.)] and 0.69 (0.18), respectively (P = 0.98). Thirteen patients from the TK-98 group and 12 from the placebo group were enrolled in the extension study. The MMT scores in both groups improved similarly. The increase of the FI scores of the shoulder flexion at 12 weeks was significantly greater in the TK-98 group [27.9 (5.67) vs 12.8 (5.67) for the right shoulder flexion, and 27.0 (5.44) vs 13.4 (5.95) for the left shoulder; P < 0.05]. Frequencies of adverse events up to 12 weeks were similar. CONCLUSION: BCAAs showed no effect on the improvement of the muscle strength evaluated by MMT and the clinical response. However, they were partly effective for improving dynamic repetitive muscle functions. TRIAL REGISTRATION: UMIN-CTR Clinical Trial, https://center6.umin.ac.jp/, UMIN000016233.

The validity of the claims-based definition of rheumatoid arthritis evaluated in 64 hospitals in Japan.

BACKGROUND: An administrative database covering a whole population such as the national database in Japan may be used to estimate the nationwide prevalence of diseases including rheumatoid arthritis (RA) when a well-validated definition of the disease is available. In Japan, the record linkage between the administrative database and medical charts in hospitals is strictly prohibited. A "hospital-based" validation study is one of few possible validation studies where claims kept inside the study hospital are rearranged into the database structure. METHODS: We selected random samples of 19,734 patients from approximately 1.6 million patients who received medical care between February 2018 and January 2019 in one of the 64 hospitals of the Tokushukai Medical Group. We excluded patients whose observation period was less than 365 days and identified 334 patients who met the definition of "possible cases of RA" whose medical charts were then independently evaluated by two rheumatologists. In a sensitivity analysis, we assessed bias due to misclassifying some patients with RA who did not meet the definition of "possible cases of RA" as a patient with no RA. RESULTS: The kappa coefficient between the two rheumatologists was 0.80. The prevalence of RA in the study population was estimated to be 0.56%. We found that [condition code of RA] and ([any disease-modifying antirheumatic drug] or [oral corticosteroid with no systemic autoimmune diseases (other than RA) and no polymyalgia rheumatica]) had a relatively high sensitivity (approximately 73%) and a high positive predictive value (approximately 80%). In a sensitivity analysis, we found that when some patients with RA who did not meet the definition of "possible cases of RA" were misclassified as a patient with no RA, then this would lead to underestimation of the prevalence of the definition-positive patients and the adjusted prevalence. CONCLUSIONS: We recommend using the claims-based definition of RA (found in the current validation study) to estimate the prevalence of RA in Japan. We also suggest estimating the adjusted prevalence using the quantitative bias analysis method, since the prevalence of the disease in the "hospital-based" validation study is different from that in the administrative database. TRIAL REGISTRATION: The current study is not a clinical trial and hence not subject to trial registration.

Response to tocilizumab and work productivity in patients with rheumatoid arthritis: 2-year follow-up of FIRST ACT-SC study.

OBJECTIVES: We evaluated long-term control of rheumatoid arthritis (RA) in Japanese paid workers (PWs) and house workers (HWs) treated with subcutaneous tocilizumab (TCZ-SC) and explored factors affecting response to TCZ-SC regarding work productivity. METHODS: This study collected data from patients with RA in the TCZ-SC +/- conventional synthetic disease-modifying antirheumatic drugs group. Factors affecting the response to tocilizumab regarding work productivity were explored using logistic regression. Differences in quality-adjusted life years (QALYs) between with/without response were analysed by a linear regression. RESULTS: Data were analysed for 357/360 patients. Patients with a ≥ 75% improvement in activity impairment (AI) were considered responders. EuroQol-5 Dimension (EQ-5D), six-item Kessler psychological distress scale score (K6), Health Assessment Questionnaire Disability Index (HAQ-DI), and the patient's disease global health by visual analogue scale were significant contributors to TCZ-SC response based on improvements in AI. Work Functioning Impairment Scale, presenteeism, EQ-5D, K6, and HAQ-DI significantly contributed to the improvement of overall work impairment in PWs. Shorter disease duration also was related to TCZ-SC response based on AI improvements. Responders had significantly larger mean QALYs than non-responders (difference = 0.2614; p < .001). CONCLUSIONS: These real-world clinical data support long-term work productivity control with TCZ-SC for biologic-naïve HWs and PWs with RA.

First external validation of sensitivity and specificity of the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for idiopathic inflammatory myopathies with a Japanese cohort.

OBJECTIVE: To externally validate the performance of the new European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria set for idiopathic inflammatory myopathies (IIM) with a Japanese cohort. METHODS: This study included 420 IIM and 402 non-IIM cases. Probability of having IIM in each patient was calculated using the collected data set. The cut-off probability was set at 55%, as recommended by EULAR/ACR. Patients classified as IIM by the criteria were further subclassified with classification trees. RESULTS: When the probability cut-off was set at 55%, the sensitivity/specificity of the new criteria to diagnose IIM were 89.3%/91.0% in the total cohort, 88.1%/95.1% without muscle biopsy data and 90.4%/65.5% with biopsy data. The cohort included 12 overlap syndrome patients with biopsy data, who were included as non-IIM cases in accordance with traditional Japanese methods. When they were included in the IIM cases, the specificity in patients with biopsy increased to 74.4%. The sensitivity/specificity of the new criteria to diagnose polymyositis/dermatomyositis (PM/DM) plus juvenile and amyopathic DM in the Japanese cohort was 87.4%/92.4%, which were greater than those of the Tanimoto's criteria revised to enable classification of amyopathic DM (ADM) (71.2%/87.8%) and were comparable with those of Bohan & Peter's criteria to diagnose those diseases except for ADM (88.4%/88.3%). CONCLUSIONS: Our study externally validated high specificity of the new criteria for the first time, although with several limitations, including low percentage of child patients. The new criteria have higher sensitivity and/or specificity in classification of PM/DM than the previously reported criteria, demonstrating its usefulness for interethnic patients.

A new in vitro model of polymyositis reveals CD8+ T cell invasion into muscle cells and its cytotoxic role.

OBJECTIVES: The hallmark histopathology of PM is the presence of CD8+ T cells in the non-necrotic muscle cells. The aim of this study was to clarify the pathological significance of CD8+ T cells in muscle cells. METHODS: C2C12 cells were transduced retrovirally with the genes encoding MHC class I (H2Kb) and SIINFEKL peptide derived from ovalbumin (OVA), and then differentiated to myotubes (H2KbOVA-myotubes). H2KbOVA-myotubes were co-cultured with OT-I CD8+ T cells derived from OVA-specific class I restricted T cell receptor transgenic mice as an in vitro model of PM to examine whether the CD8+ T cells invade into the myotubes and if the myotubes with the invasion are more prone to die than those without. Muscle biopsy samples from patients with PM were examined for the presence of CD8+ T cells in muscle cells. The clinical profiles were compared between the patients with and without CD8+ T cells in muscle cells. RESULTS: Analysis of the in vitro model of PM with confocal microscopy demonstrated the invasion of OT-I CD8+ T cells into H2KbOVA-myotubes. Transmission electron microscopic analysis revealed an electron-lucent area between the invaded CD8+ T cell and the cytoplasm of H2KbOVA-myotubes. The myotubes invaded with OT-I CD8+ T cells died earlier than the uninvaded myotubes. The level of serum creatinine kinase was higher in patients with CD8+ T cells in muscle cells than those without these cells. CONCLUSION: CD8+ T cells invade into muscle cells and contribute to muscle injury in PM. Our in vitro model of PM is useful to examine the mechanisms underlying muscle injury induced by CD8+ T cells.

Long-term efficacy and safety of tocilizumab in refractory Takayasu arteritis: final results of the randomized controlled phase 3 TAKT study.

OBJECTIVE: To investigate the long-term efficacy and safety of the IL-6 receptor antibody tocilizumab in patients with Takayasu arteritis (TAK). METHODS: Patients completing the randomized, double-blind, placebo-controlled period of the TAKT (Takayasu arteritis Treated with Tocilizumab) trial were followed up during open-label extended treatment with weekly s.c. tocilizumab 162 mg for up to 96 weeks or longer, with oral glucocorticoid tapering performed at the investigators' discretion. Endpoints of the extension analysis included steroid-sparing effects of tocilizumab, imaging data, patient-reported outcomes (36-Item Short Form Health Survey) and safety. RESULTS: All 36 patients enrolled in the double-blind period entered the open-label extension; 28 patients received tocilizumab for 96 weeks. The median glucocorticoid dose was 0.223 mg/kg/day at the time of relapse before study entry, 0.131 mg/kg/day (interquartile range 0.099, 0.207) after 48 weeks and 0.105 mg/kg/day (interquartile range 0.039, 0.153) after 96 weeks. Overall, 46.4% of patients reduced their dose to <0.1 mg/kg/day, which was less than half the dose administered at relapse before study entry (mean difference -0.120 mg/kg/day; 95% CI -0.154, -0.087). Imaging evaluations indicated that most patients' disease was improved (17.9%) or stable (67.9%) after 96 weeks compared with baseline. Mean 36-Item Short Form Health Survey physical and mental component summary scores and 7 of 8 domain scores were clinically improved from baseline and maintained over 96 weeks of tocilizumab treatment. No unexpected safety issues were reported. CONCLUSION: These results in patients with Takayasu arteritis provide evidence of a steroid-sparing effect and improvements in well-being during long-term treatment with once-weekly tocilizumab 162 mg, with no new safety concerns. TRIAL REGISTRATION: JAPIC Clinical Trials Information, http://www.clinicaltrials.jp/user/cteSearch_e.jsp, JapicCTI-142616.

The development of quality indicators for systemic lupus erythematosus using electronic health data: A modified RAND appropriateness method.

Objective: Quality indicators (QIs) are tools that standardize evaluations in terms of the minimum acceptable quality of care, presumably contributing for the better management of patients with systemic lupus erythematosus (SLE). This study aimed to develop QIs for SLE using electronic health data.Methods: The modified RAND/UCLA Appropriateness Method was used to develop the QIs. First, a literature review was conducted. Second, the candidate QI items that were available to be evaluated using the electronic health data were extracted. Third, the appropriateness of the items was assessed via rating rounds and panelists' discussions.Results: We found 3621 articles in the initial search. Finally, 34 studies were reviewed, from which 17 potential indicators were extracted as candidate QIs. Twelve indicators were selected as the final QI set through the process of appropriateness. The median appropriateness of these 12 indicators was at least 7.5, and all of them were without disagreement. The QI included assessment of disease activity, treatment of SLE, drug toxicity monitoring, treatment of glucocorticoid complications, and assessment of SLE complications.Conclusion: We formulated 12 QIs for the assessment of patients with SLE based on electronic medical data. Our QI set would be a practical tool as a quality measure.

Higher risk of hospitalized infection, cardiovascular disease, and fracture in patients with rheumatoid arthritis determined using the Japanese health insurance database.

Objective: To evaluate the risk of hospitalized infection (HI), cardiovascular disease (CVD), stroke, and fracture in rheumatoid arthritis (RA) patients compared with non-RA patients using the Japanese health insurance database. Method: Among individuals aged ≥18 years, RA cases were defined to have one RA diagnostic code and receiving ≥1 disease-modifying antirheumatic drug between 2005 and 2013 (n = 6,712). Age-, sex-, calendar year of the observation start-, and observation length-matched non-RA cases were selected at 1:5 (n = 33,560). Hazard ratios (HRs) were calculated using the time-dependent Cox regression analysis. Results: Median age of the patients was 52.0 years. The incidence rates of HI, CVD, and fracture in the RA group were 2.42/100 person-years (PY), 4.94/1,000 PY, and 10.59/1,000 PY. The crude incidence rate ratios (95% CI) (RA vs. non-RA) for HI, CVD, and fracture were 2.47 (2.20-2.77), 1.89 (1.49-2.41), and 3.35 (2.80-4.02). The adjusted HR (95% CI) (RA vs. non-RA) was significantly elevated (HI, 1.74 [1.52-1.99], CVD, 1.38 [1.04-1.85], and fracture, 1.88 (1.54-2.31)]. Conclusion: The relatively young RA population had significantly higher risks of these complications than the non-RA, indicating importance of prevention of them even at young ages in clinical settings.

Treatment consensus for management of polymyositis and dermatomyositis among rheumatologists, neurologists and dermatologists.

Although rheumatologists, neurologists and dermatologists see patients with polymyositis (PM) and dermatomyositis (DM), their management appears to vary depending on the physician's specialty. The aim of the present study was to establish the treatment consensus among specialists of the three fields to standardize the patient care. We formed a research team supported by a grant from the Ministry of Health, Labor and Welfare, Japan. Clinical questions (CQ) on the management of PM and DM were raised. A published work search on CQ was performed primarily using PubMed. Using the nominal group technique, qualified studies and results in the published work were evaluated and discussed to reach consensus recommendations. They were sent out to the Japan College of Rheumatology, Japanese Society of Neurology and Japanese Dermatological Association for their approval. We reached a consensus in 23 CQ and made recommendations and a decision tree for management was proposed. They were officially approved by the three scientific societies. In conclusion, a multidisciplinary treatment consensus for the management of PM and DM was established for the first time.

Splicing variant of WDFY4 augments MDA5 signalling and the risk of clinically amyopathic dermatomyositis.

OBJECTIVES: Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of rare autoimmune diseases in which both genetic and environmental factors play important roles. To identify genetic factors of IIM including polymyositis, dermatomyositis (DM) and clinically amyopathic DM (CADM), we performed the first genome-wide association study for IIM in an Asian population. METHODS: We genotyped and tested 496 819 single nucleotide polymorphism for association using 576 patients with IIM and 6270 control subjects. We also examined the causal mechanism of disease-associated variants by in silico analyses using publicly available data sets as well as by in in vitro analyses using reporter assays and apoptosis assays. RESULTS: We identified a variant in WDFY4 that was significantly associated with CADM (rs7919656; OR=3.87; P=1.5×10-8). This variant had a cis-splicing quantitative trait locus (QTL) effect for a truncated WDFY4isoform (tr-WDFY4), with higher expression in the risk allele. Transexpression QTL analysis of this variant showed a positive correlation with the expression of NF-κB associated genes. Furthermore, we demonstrated that both WDFY4 and tr-WDFY4 interacted with pattern recognition receptors such as TLR3, TLR4, TLR9 and MDA5 and augmented the NF-κB activation by these receptors. WDFY4 isoforms also enhanced MDA5-induced apoptosis to a greater extent in the tr-WDFY4-transfected cells. CONCLUSIONS: As CADM is characterised by the appearance of anti-MDA5 autoantibodies and severe lung inflammation, the WDFY4 variant may play a critical role in the pathogenesis of CADM.

Current diagnosis and treatment of polymyositis and dermatomyositis.

Idiopathic inflammatory myopathies (IIMs) are heterogeneous disorders that affect the skeletal muscles. Polymyositis, dermatomyositis, and inclusion body myositis are major IIM subsets. Immune-mediated necrotizing myopathy became recognized as a potentially new IIM subset. Since the new classification criteria published by the International Myositis Classification Criteria Project have higher sensitivity and specificity for IIM classification and subclassification than the previous criteria, they should help precise diagnosis. It should be noted that several tests available in current clinical practice, such as electromyography, magnetic resonance imaging, and other myositis-specific autoantibodies than anti-Jo-1 antibodies, were not included in the new criteria. As for treatment, glucocorticoids are used empirically as the first-line treatment despite their various adverse effects. Concomitant treatment with steroid-sparing immunosuppressive agents, including methotrexate, azathioprine, calcineurin inhibitors, mycophenolate mofetil, and cyclophosphamide, reduces successfully initial glucocorticoid doses for the remission induction, the relapse risk during glucocorticoid tapering, and adverse effects of glucocorticoids. Treatment with biologics, including rituximab and abatacept, seems promising in some IIM patients. Multi-target treatment with glucocorticoids and several steroid-sparing immunosuppressive agents is effective in refractory IIM patients. Considering proven steroid-sparing efficacy and tolerability of multi-target treatment in patients with other autoimmune diseases, it should be a good therapeutic option for IIMs.

A case of chronic myelomonocytic leukemia complicated with spondyloarthritis.

Chronic myelomonocytic leukemia (CMML), a clonal hematopoietic stem cell disorder with myelodysplastic and myeloproliferative overlap feature, is frequently associated with autoimmune diseases, such as vasculitis, polyarthritis, and neutrophilic dermatosis. We herein report the first case of CMML complicated with spondyloarthritis (SpA). A 64-year-old female patient, admitted to our hospital with buttock pain alternating left and right, was found to have sacroiliitis and spondylitis by contrast magnetic resonance imaging. Peripheral blood test and bone marrow biopsy revealed an increase of monocytes with trilineage dysplasia. We made a diagnosis of CMML. Although arthritic symptoms and imaging findings initially improved by azacitidine, CMML was thereafter transformed into acute myeloid leukemia. She is scheduled to hematopoietic stem cell transplantation. The concomitant onset of sacroiliitis with CMML suggested that her SpA feature was a paraneoplastic phenomenon of CMML. Thus, we must be aware that myelodysplastic syndrome including CMML can manifest as SpA.

Origins of fibroblasts in rheumatoid synovial tissues: Implications from organ fibrotic models.

Fibroblasts play crucial roles in the pathogenesis of rheumatoid arthritis (RA). Accumulation of fibroblasts in the synovial tissues characterizes the pathology of RA. Understanding how fibroblasts accumulate could lead to discovery of new therapeutic targets in RA treatment, while current antirheumatic therapies still have problems in efficacy and safety. In this regard, several studies have revealed cellular origins of fibroblasts in fibrotic tissues in murine models of organ fibrosis. Some studies employed lineage tracing, which bring generally convincing results, using transgenic mice. They demonstrated that resident fibroblasts, pericytes, mesenchymal stem cells, epithelial cells, endothelial cells and bone-marrow-derived and circulating cells can be cellular origins of fibroblasts in organ fibrotic tissues. In this review, we summarize and discuss available evidence for the origins of fibroblasts accumulating in the arthritic synovial tissues and organ fibrotic tissues.

Survey of the awareness of adult rheumatologists regarding transitional care for patients with juvenile idiopathic arthritis in Japan.

OBJECTIVES: To understand the current status of adult rheumatology care for patients who had previously had juvenile idiopathic arthritis (JIA) (excluding systemic JIA), and to identify issues interfering with the transition from pediatric to adult care in Japan. METHODS: Questionnaire-based survey among 30 adult rheumatologists. RESULTS: Eighty-seven percent of adult rheumatologists responded that they had provided medical care to adults who had had JIA; 44% of them had felt hesitation or anxiety when providing such care. The reasons for this included lack of independence of the patients, lack of knowledge and experience among adult rheumatologists, and lack of preparation for accepting such patients. Many adult rheumatologists believed that the timing of transition from pediatric to adult rheumatology care must be considered based on therapeutic regimens or clinical conditions/disease states, not solely chronological age. A majority of adult rheumatologists showed great interest in transitional care for JIA patients and desired to communicate better with pediatric rheumatologists. CONCLUSION: Transitional care for JIA patients is not sufficiently developed in Japan. Education and advocate campaign of transitional care is required for adult rheumatologists as well as patients and their parents.

Evaluation of the alternative classification criteria of systemic lupus erythematosus established by Systemic Lupus International Collaborating Clinics (SLICC).

OBJECTIVE: To evaluate the performance of the 2012 Systemic Lupus International Collaborating Clinics criteria (SLICC-12) on classifying systemic lupus erythematosus (SLE) in an uncontrolled multi-centered study with real-life scenario of the patients in Japan. METHODS: This study comprised 495 patients with SLE or non-SLE rheumatic diseases and allied conditions from 12 institutes in Japan. Chart review of each patient was performed by the 27 expert rheumatologists and diagnosis of 487 cases reached to the consensus. Value of the SLICC-12 on SLE classification was analyzed comparing with the 1997 revised American College of Rheumatology SLE classification criteria (ACR-97) employing the expert-consented diagnoses. RESULTS: Compared to the ACR-97, the SLICC-12 had a higher sensitivity (ACR-97 vs. SLICC-12: 0.88 vs. 0.99, p < .01) and comparable specificity (0.85 vs. 0.80). The rate of misclassification (0.14 vs. 0.11) or the area under the receiver operating characteristic curves (0.863 vs. 0.894) was not statistically different. In the cases that diagnoses corresponded in high rates among experts, both criteria showed high accordance of SLE classification over 85% with the expert diagnoses. CONCLUSION: Although employment of SLICC-12 for the classification for SLE should be carefully considered, the SLICC-12 showed the higher sensitivity on classifying SLE in Japanese population.

2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups.

OBJECTIVE: To develop and validate new classification criteria for adult and juvenile idiopathic inflammatory myopathies (IIM) and their major subgroups. METHODS: Candidate variables were assembled from published criteria and expert opinion using consensus methodology. Data were collected from 47 rheumatology, dermatology, neurology and paediatric clinics worldwide. Several statistical methods were used to derive the classification criteria. RESULTS: Based on data from 976 IIM patients (74% adults; 26% children) and 624 non-IIM patients with mimicking conditions (82% adults; 18% children), new criteria were derived. Each item is assigned a weighted score. The total score corresponds to a probability of having IIM. Subclassification is performed using a classification tree. A probability cut-off of 55%, corresponding to a score of 5.5 (6.7 with muscle biopsy) 'probable IIM', had best sensitivity/specificity (87%/82% without biopsies, 93%/88% with biopsies) and is recommended as a minimum to classify a patient as having IIM. A probability of ≥90%, corresponding to a score of ≥7.5 (≥8.7 with muscle biopsy), corresponds to 'definite IIM'. A probability of <50%, corresponding to a score of <5.3 (<6.5 with muscle biopsy), rules out IIM, leaving a probability of ≥50 to <55% as 'possible IIM'. CONCLUSIONS: The European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for IIM have been endorsed by international rheumatology, dermatology, neurology and paediatric groups. They employ easily accessible and operationally defined elements, and have been partially validated. They allow classification of 'definite', 'probable' and 'possible' IIM, in addition to the major subgroups of IIM, including juvenile IIM. They generally perform better than existing criteria.

Direct suppression of autoaggressive CD8+ T cells with CD80/86 blockade in CD8+ T cell-mediated polymyositis models of mice.

OBJECTIVES: CD80/86 blockade to inhibit CD28 costimulation suppressed alloreactive human and murine CD4+ T cells but not alloreactive CD8+ T cells. In contrast, CD28 costimulation augments CD8+ T cell-mediated cell lysis in antigen-nonspecific stimulation. The present study was conducted to discern whether the CD80/86 blockade exerts therapeutic effects on CD8+ T cell-mediated polymyositis (PM) models of mice and whether the effects could be attributable to direct suppression of autoantigen-specific CD8+ T cells. METHODS: C protein-induced myositis (CIM) was induced in mice with intradermal injection of C protein fragments. C protein peptide-induced myositis (CPIM), in which autoaggressive CD8+ T cells are activated without CD4+ T cell help, was induced in mice with intravenous injection of dendritic cells (DCs) loaded with CD8+ T cell-epitope peptides derived from the C protein fragment. The immunised mice were treated with CTLA4-Ig or anti-CD80 and anti-CD86 antibodies (anti-CD80/86 Abs). The muscles were evaluated histologically 21 days after the C protein immunisation or 7 days after the DC injection. RESULTS: CIM was suppressed in the mice treated with CTLA4-Ig or anti-CD80/86 Abs administered prophylactically from the day of immunisation and therapeutically after the disease onset. CPIM was suppressed when CTLA4-Ig was administered concurrently with the DC injection. CONCLUSIONS: The CD80/86 blockade was effective in PM models of mice. Amelioration of CPIM indicates direct suppression of CD8+ T cells by the CD80/86 blockade. CTLA4-Ig should be a potential therapeutic agent of PM and other CD8+T cell-mediated diseases by suppressing both autoantigen-specific CD4+ and CD8+ T cells.

Temporal expression of growth factors triggered by epiregulin regulates inflammation development.

In this study, we investigated the relationship between several growth factors and inflammation development. Serum concentrations of epiregulin, amphiregulin, betacellulin, TGF-α, fibroblast growth factor 2, placental growth factor (PLGF), and tenascin C were increased in rheumatoid arthritis patients. Furthermore, local blockades of these growth factors suppressed the development of cytokine-induced arthritis in mice by inhibiting chemokine and IL-6 expressions. We found that epiregulin expression was early and followed by the induction of other growth factors at different sites of the joints. The same growth factors then regulated the expression of epiregulin at later time points of the arthritis. These growth factors were increased in patients suffering from multiple sclerosis (MS) and also played a role in the development of an MS model, experimental autoimmune encephalomyelitis. The results suggest that the temporal expression of growth factors is involved in the inflammation development seen in several diseases, including rheumatoid arthritis and MS. Therefore, various growth factor pathways might be good therapeutic targets for various inflammatory diseases.