Polymyositis
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Pubmed
Journal: Lancet (London, England)
November/18/2003
Abstract

The inflammatory myopathies, commonly described as idiopathic, are the largest group of acquired and potentially treatable myopathies. On the basis of unique clinical, histopathological, immunological, and demographic features, they can be differentiated into three major and distinct subsets: dermatomyositis, polymyositis, and inclusion-body myositis. Use of new diagnostic criteria is essential to discriminate between them and to exclude other disorders. Dermatomyositis is a microangiopathy affecting skin and muscle; activation and deposition of complement causes lysis of endomysial capillaries and muscle ischaemia. In polymyositis and inclusion-body myositis, clonally expanded CD8-positive cytotoxic T cells invade muscle fibres that express MHC class I antigens, which leads to fibre necrosis via the perforin pathway. In inclusion-body myositis, vacuolar formation with amyloid deposits coexists with the immunological features. The causative autoantigen has not yet been identified. Upregulated vascular-cell adhesion molecule, intercellular adhesion molecule, chemokines, and their receptors promote T-cell transgression, and various cytokines increase the immunopathological process. Early initiation of therapy is essential, since both polymyositis and dermatomyositis respond to immunotherapeutic agents. New immunomodulatory agents currently being tested in controlled trials may prove promising for difficult cases.

Pubmed
Journal: Lancet (London, England)
March/28/2001
Abstract

BACKGROUND

Dermatomyositis and polymyositis are associated with cancer, but previous nationwide studies have not had sufficient cases to test the association between myositis and specific cancer types. Our aim was to investigate the risk of specific cancer types in individuals with dermatomyositis and polymyositis.

METHODS

We did a pooled analysis of published national data from Sweden, Denmark, and Finland. All patients with dermatomyositis and polymyositis (> or =15 years old) were identified by discharge diagnosis from the Swedish National Board of Health (1964-83), Danish Hospital Discharge Registry (1977-89), and Finnish National Board of Health (1969-85). Personal details were matched to national cancer registries, to identify all cases of cancer up to 1987 in Sweden, 1995 in Denmark, and 1997 in Finland, and to national death registries for the same periods. We calculated standardised incidence ratios (SIR) for individual cancer sites for dermatomyositis and polymyositis separately, using national cancer rates by country, sex, age, and date.

RESULTS

We identified 618 cases of dermatomyositis, of whom 198 had cancer. 115 of the 198 developed cancer after diagnosis of dermatomyositis. This disease was strongly associated with malignant disease (SIR 3.0, 95% CI 2.5-3.6), particularly ovarian (10.5, 6.1-18.1), lung (5.9, 3.7-9.2), pancreatic (3.8, 1.6-9.0), stomach (3.5, 1.7-7.3), and colorectal (2.5, 1.4-4.4) cancers, and non-Hodgkin lymphoma (3.6, 1.2-11.1). 137 of the 914 cases of polymyositis had cancer, which developed after diagnosis of polymyositis in 95. Polymyositis was associated with a raised risk of non-Hodgkin lymphoma (3.7, 1.7-8.2), and lung (2.8, 1.8-4.4) and bladder cancers (2.4, 1.3-4.7). In both dermatomyositis and polymyositis, risk of malignant disease was highest at time of myositis diagnosis.

CONCLUSIONS

Our results provide evidence that dermatomyositis is strongly associated with a wide range of cancers. The overall risk of malignant disease is also modestly increased among patients with polymyositis, with an excess for some cancers.

Pubmed
Journal: Circulation
October/17/2004
Abstract

Statin monotherapy is generally well tolerated, with a low frequency of adverse events. The most important adverse effects associated with statins are myopathy and an asymptomatic increase in hepatic transaminases, both of which occur infrequently. Because statins are prescribed on a long-term basis, however, possible interactions with other drugs deserve particular attention, as many patients will typically receive pharmacological therapy for concomitant conditions during the course of statin treatment. This review summarizes the pharmacokinetic properties of statins and emphasizes their clinically relevant drug interactions.

Pubmed
Journal: Seminars in arthritis and rheumatism
August/9/1995
Abstract

Distinct profiles of autoantibodies directed to intracellular antigens can be detected in the systemic connective tissue diseases. They aid in establishing the correct diagnosis and are included in many sets of diagnostic criteria, such as the ones developed for systemic lupus erythematosus (anti-Smith antigen and anti-double-strand DNA antibodies), mixed connective tissue disease (anti-U1-nuclear ribonucleoprotein antibodies), and Sjögren's syndrome (SS) (anti-SS-A/Ro and anti-SS-B/La antibodies). They are useful prognostic markers in some situations and facilitate clinical and treatment follow-up. Autoantibodies have also been used as probes to gain insights into cell biology, helping to isolate and purify intracellular proteins involved in key cellular functions. We give detailed information on two of the most useful techniques for the detection of autoantibodies in the clinical and research laboratory settings, indirect immunofluorescence and immunoblotting. We also discuss several of the antigen-autoantibody systems found in systemic lupus erythematosus (Smith antigen, U1-nuclear ribonucleoprotein, SS-A/Ro, SS-B/La, proliferating cell nuclear antigen ribosomal ribonucleoprotein, double-strand DNA, histones, antiphospholipids, Ku, Ki/SL), systemic sclerosis (centromere, topo I, RNA polymerases, fibrillarin, polymyositis-Scl, Th/To), polymyositis/dermatomyositis (transferRNA synthetases, signal recognition particle, and others), and SS (SS-A/Ro, SS-B/La, nucleolar organizing region-90, p80-coilin), addressing their clinical significance, common detection methods, immunogenetic associations, and the molecular and cellular biology of the cognate antigens.

Pubmed
Journal: Arthritis and rheumatism
April/10/2013
Abstract

OBJECTIVE

To assess the safety and efficacy of rituximab in a randomized, double-blind, placebo-phase trial in adult and pediatric myositis patients.

METHODS

Adults with refractory polymyositis (PM) and adults and children with refractory dermatomyositis (DM) were enrolled. Entry criteria included muscle weakness and ≥2 additional abnormal values on core set measures (CSMs) for adults. Juvenile DM patients required ≥3 abnormal CSMs, with or without muscle weakness. Patients were randomized to receive either rituximab early or rituximab late, and glucocorticoid or immunosuppressive therapy was allowed at study entry. The primary end point compared the time to achieve the International Myositis Assessment and Clinical Studies Group preliminary definition of improvement (DOI) between the 2 groups. The secondary end points were the time to achieve ≥20% improvement in muscle strength and the proportions of patients in the early and late rituximab groups achieving the DOI at week 8.

RESULTS

Among 200 randomized patients (76 with PM, 76 with DM, and 48 with juvenile DM), 195 showed no difference in the time to achieving the DOI between the rituximab late (n = 102) and rituximab early (n = 93) groups (P = 0.74 by log rank test), with a median time to achieving a DOI of 20.2 weeks and 20.0 weeks, respectively. The secondary end points also did not significantly differ between the 2 treatment groups. However, 161 (83%) of the randomized patients met the DOI, and individual CSMs improved in both groups throughout the 44-week trial.

CONCLUSIONS

Although there were no significant differences in the 2 treatment arms for the primary and secondary end points, 83% of adult and juvenile myositis patients with refractory disease met the DOI. The role of B cell-depleting therapies in myositis warrants further study, with consideration for a different trial design.

Pubmed
Journal: Annals of the rheumatic diseases
September/25/2006
Abstract

OBJECTIVE

To study the presence of citrullinated proteins in inflammatory conditions and in clinically non-affected tissues of controls.

METHODS

Synovial biopsy specimens from 19 patients with rheumatoid arthritis and 10 healthy controls were investigated by immunohistochemistry. Additionally, muscle tissue from 5 patients with polymyositis and from 7 healthy controls, intestinal tissue from macroscopically affected and non-affected areas from 10 patients with inflammatory bowel disease (IBD) and tonsil tissues from 4 chronically inflamed tonsils were studied.

RESULTS

Citrullinated proteins were present in all synovial biopsy specimens from patients with rheumatoid arthritis, whereas only three of 10 healthy synovial biopsy specimens showed scarce amounts of citrullination. Citrullination was also present in all myositis-affected muscles, whereas it was absent in the muscle tissues of controls. All tonsil biopsy specimens studied were positive for citrulline. Even though more frequently detected in the macroscopically affected colonic areas, no marked difference was observed in the pattern or extent of citrullination between the macroscopically affected and non-affected intestinal IBD tissues.

CONCLUSIONS

Citrullination is present in a wide range of inflammatory tissues, suggesting that this process is inflammation dependent rather than disease dependent.

Pubmed
Journal: The Journal of cell biology
September/30/2003
Abstract

Members of the synaptotagmin family have been proposed to function as Ca2+ sensors in membrane fusion. Syt VII is a ubiquitously expressed synaptotagmin previously implicated in plasma membrane repair and Trypanosoma cruzi invasion, events which are mediated by the Ca2+-regulated exocytosis of lysosomes. Here, we show that embryonic fibroblasts from Syt VII-deficient mice are less susceptible to trypanosome invasion, and defective in lysosomal exocytosis and resealing after wounding. Examination of mutant mouse tissues revealed extensive fibrosis in the skin and skeletal muscle. Inflammatory myopathy, with muscle fiber invasion by leukocytes and endomysial collagen deposition, was associated with elevated creatine kinase release and progressive muscle weakness. Interestingly, similar to what is observed in human polymyositis/dermatomyositis, the mice developed a strong antinuclear antibody response, characteristic of autoimmune disorders. Thus, defective plasma membrane repair in tissues under mechanical stress may favor the development of inflammatory autoimmune disease.

Pubmed
Journal: Medicine
August/10/2005
Abstract

Our objective was to improve the currently imperfect classifications of idiopathic inflammatory myopathies (IIM). In clinical practice, overlap features are common in IIM. This provided a rationale for positioning overlap clinical features at the core of a new classification system. We conducted a longitudinal study of 100 consecutive adult French Canadian patients with IIM. Clinical and laboratory data were obtained by retrospective chart review. Sera were analyzed for autoantibodies (aAbs) by protein A-assisted immunoprecipitation and double immunodiffusion. Overlap aAbs encompassed aAbs to synthetases, systemic sclerosis-associated aAbs, anti-signal recognition particle (SRP) and anti-nucleoporins. Patients were classified both at IIM diagnosis, based on data at presentation, and at the end of follow-up, based on cumulative findings. Three classifications were used: 1) the Bohan and Peter original classification, 2) a new version of that classification as modified by us, and 3) a novel clinicoserologic classification. As investigators were blinded to aAb results, the modified classification is strictly a clinical classification. Its core concept is the attribution of diagnostic significance to the presence of overlap features, that is, their presence resulted in a diagnosis of overlap myositis (OM). This approach allowed direct comparison with the original Bohan and Peter classification. By integrating aAb results to the modified classification, we also defined the clinicoserologic classification, which allowed to examine the added value of aAbs to diagnostic, therapeutic and prognostic stratification. Whereas polymyositis (PM) was the most common IIM according to the original classification, accounting for 45% of the cohort at diagnosis, its frequency fell to 14% with the modified classification. Conversely, while the frequency of myositis associated with connective tissue disease was 24% according to the original classification, the frequency of OM was 60% when using the modified classification. At last follow-up, the frequency of PM fell further to only 9%, while the frequency of OM rose to 67%. Systemic sclerosis was the most common connective tissue disease associated with IIM, accounting for 42.6% of OM patients and 29% of the cohort. The frequencies of overlap aAbs in the cohort and in OM patients were 48% and 70.5% (n =48/68), respectively. The presence of overlap aAbs at IIM diagnosis identified additional OM patients unrecognized by the modified classification. The sensitivity of the modified classification for OM at diagnosis was 87%, suggesting that clinicians may rely on the modified classification for identification of most OM patients, while awaiting results of aAb assays. The new classifications predicted the response to prednisone and IIM course. Using stringent definitions, IIM was classified as responsive or refractory after an adequate initial corticosteroid therapy, and the disease course as monophasic or chronic after a single adequate trial of prednisone. PM was always chronic and was associated with the highest rate (50%) of refractoriness to initial corticosteroid treatment. Dermatomyositis was almost always chronic (92% rate); however, its responsiveness to initial corticosteroid treatment was high (87%). OM was almost always responsive to corticosteroids (89%-100% rates). When OM patients were divided according to aAb subsets, anti-synthetase, SRP, or nucleoporin aAbs were markers for chronic myositis, whereas aAbs to U1RNP, Pm-Scl, or Ku were markers for monophasic myositis. We conclude that the original Bohan and Peter classification should be abandoned as it leads to misclassification of patients. Much of IIM is composed of OM. The proposed modified and clinicoserologic classifications have diagnostic, prognostic, and therapeutic value.

Pubmed
Journal: American journal of respiratory and critical care medicine
January/24/2002
Abstract

We report findings in 70 patients with both diffuse interstitial lung disease and either polymyositis (PM) or dermatomyositis (DM). Initial presentations were most commonly either musculoskeletal (arthralgias, myalgias, and weakness) or pulmonary (cough, dyspnea, and fever) symptoms alone; in only 15 patients (21.4%) did both occur simultaneously. Pulmonary disease usually took the form of acute to subacute antibiotic-resistant community-acquired pneumonia. Chest radiographs and computed tomography most commonly demonstrated bilateral irregular linear opacities involving the lung bases; occasionally consolidation was present. Jo-1 antibody was present in 19 (38%) of 50 patients tested. Synchronous associated malignancy was present in 4 of 70 patients (5.7%). Surgical lung biopsies disclosed nonspecific interstitial pneumonia (NSIP) in 18 of 22 patients (81.8%), organizing diffuse alveolar damage (DAD) in 2, bronchiolitis obliterans organizing pneumonia (BOOP) in 1, and usual interstitial pneumonia (UIP) in 1. Treatment usually included prednisone in 40-60 mg/d dosages for initial control, followed by lower dose prednisone plus an immunosuppressive agent such as azathioprine or methotrexate for disease suppression. Survival was significantly better than that observed for historical control subjects with idiopathic UIP, and was more consistent with survival previously reported in idiopathic NSIP. There was no difference in survival between Jo-1 positive and Jo-1 negative groups.

Pubmed
Journal: Journal of the National Cancer Institute
December/7/2004
Abstract

BACKGROUND

Patients with rheumatoid arthritis or polymyositis treated with methotrexate (MTX) develop Epstein-Barr virus (EBV)-positive lymphomas more frequently than patients treated with other, equally immunosuppressive regimens. Here we determined whether MTX, in contrast to other commonly used medications for rheumatoid arthritis or polymyositis, is unique in its ability to induce the release of infectious EBV from latently infected cells.

METHODS

The effect of MTX and other immunosuppressant drugs on EBV replication in vitro was assessed using latently infected EBV-positive lymphoblastoid and gastric carcinoma cell lines. Inhibitors of signal transduction pathways were used to define requirements for induction of lytic infection. Drug effects on transcription of the two EBV immediate-early promoters (BRLF1 and BZLF1) and on promoter constructs lacking cis-acting sequences required for activation by other effectors was examined using reporter gene assays. EBV viral load in rheumatoid arthritis and polymyositis patients receiving MTX was compared with that in patients receiving other immunosuppressive medications. Statistical tests were two-sided.

RESULTS

MTX activated the release of infectious EBV from latently infected cell lines in vitro, and MTX treatment was associated with activation of the two viral immediate-early promoters in reporter gene assays. Induction of lytic EBV infection by MTX required the p38 MAP kinase, PI3 kinase, and MEK pathways and specific cis-acting motifs in the two viral immediate-early promoters. Patients treated with MTX-containing regimens had statistically significantly higher mean EBV loads in their blood than patients treated with immunosuppressing regimens that did not include MTX (40 EBV copies per 10(6) cellular genomes versus 5.1 copies; geometric mean fold difference in copies = 10.8, 95%, confidence interval = 3.0 to 38; P = .011).

CONCLUSIONS

MTX may promote EBV-positive lymphomas in rheumatoid arthritis and polymyositis patients by its immunosuppressive properties as well as by reactivating latent EBV.

Pubmed
Journal: Neurology
January/11/2004
Abstract

OBJECTIVE

To investigate the immunolocalization and activation of nuclear factor-kappaB (NF-kappaB) in polymyositis, dermatomyositis, and Duchenne muscular dystrophy (DMD).

BACKGROUND

NF-kappaB is a major transcription factor modulating the cellular immune, inflammatory, and proliferative responses. In skeletal muscle it was demonstrated to play a role in the expression of inducible genes in response to oxidative stress and ischemia/reperfusion injury, and also in myonuclear apoptosis and muscle catabolism. Some data suggest that NF-kappaB may play a role in the pathogenesis of inclusion body myositis.

METHODS

Muscle samples from five patients each with polymyositis, dermatomyositis, and DMD and 10 normal controls were studied by immunocytochemistry and Western blot of nuclear extracts for the activated form of NF-kappaB. NF-kappaB DNA binding activity was studied by electrophoretic mobility shift assay (EMSA).

RESULTS

Immunoreactivity for NF-kappaB was found in the cytoplasm of all regenerating fibers and in 20 to 40% of necrotic fibers. Western blot analysis of nuclear extracts showed a single band corresponding to 65 kd in all patients. EMSA analysis confirmed activation of NF-kappaB pathway in inflammatory myopathies and, to a lesser extent, also in DMD.

CONCLUSIONS

These data indicate that nuclear factor-kappaB pathway is activated in polymyositis, dermatomyositis, and Duchenne muscular dystrophy. It may play a role in modulating the immune response and in regulating myogenesis and muscle repair.

Pubmed
Journal: Arthritis and rheumatism
December/18/2007
Abstract

OBJECTIVE

To apply gene expression profiling to the study of peripheral blood mononuclear cells from patients with inflammatory myopathies, in order to provide insight into disease pathogenesis and identify potential biomarkers associated with disease activity.

METHODS

We used Affymetrix whole-genome microarrays to measure the expression of approximately 38,500 genes in 65 blood and 15 muscle samples from 44 patients with dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM), myasthenia gravis, or genetically determined myopathies and from 12 healthy volunteers. In 9 patients, 2 samples were obtained at different time points, when disease was either active or improving, and these paired blood samples were also compared. Bioinformatics techniques were used to identify genes with significant differential expression among diagnostic categories and in relation to disease activity. We corroborated the microarray data with quantitative real-time reverse transcriptase-polymerase chain reaction.

RESULTS

Most patients with active DM or PM, but not patients with IBM, had significant and high up-regulation of the type I interferon-alpha/beta (IFNalpha/beta)-inducible genes in blood. Furthermore, the up-regulation of these genes correlated with disease activity in DM and PM, with down-regulation occurring when disease was controlled with treatment.

CONCLUSIONS

DM and PM are diseases characterized by the systemic overexpression of IFNalpha/beta-inducible genes. The magnitude of the overexpression of these genes is higher in DM and correlates with disease activity in both disorders. Although PM and IBM have been modeled as having similar immunologic processes occurring within muscle, there are substantial differences in the expression of IFNalpha/beta-inducible genes in blood in these diseases.

Pubmed
Journal: Rheumatology (Oxford, England)
July/5/2009
Abstract

The idiopathic inflammatory myopathies (IIMs)--DM and PM--have been historically defined by broad clinical and pathological criteria. These conditions affect both adults and children with clinical features including muscle weakness, skin disease, internal organ involvement and an association with cancer in adults. Using a clinico-serological approach, DM and PM can be defined into more homogeneous subsets. Over the last few years, myositis-specific autoantibodies (MSAs) have been better characterized including autoantibodies directed against the aminoacyl tRNA-synthetase enzymes, the signal-recognition particle and the Mi-2 protein. In addition, clinically significant novel autoantibodies--anti-CADM-140, anti-SAE (small ubiquitin-like modifier activating enzyme), anti-p155/140 and anti-p140--have been described in the adult and juvenile disease spectrum. MSAs are directed against cytoplasmic or nuclear components involved in key regulatory intracellular processes including protein synthesis, translocation and gene transcription. The striking association between unique serological profiles and distinct clinical phenotypes suggests that target autoantigens may play a role in disease induction and propagation. In this review, we discuss the clinical utility and pathogenic significance of MSAs in disease expression.

Pubmed
Journal: Arthritis and rheumatism
January/28/2003
Abstract

OBJECTIVE

To assess prevalence, characteristics, and long-term outcome of interstitial lung disease (ILD) in polymyositis (PM) and dermatomyositis (DM). To determine predictive variables of ILD course in PM/DM, and to define both clinical and biochemical features associated with ILD onset in PM/DM.

METHODS

The medical records of 156 consecutive PM/DM patients in 3 medical centers were reviewed.

RESULTS

Thirty-six PM/DM patients (23.1%) developed ILD. We observed that 19.4% of patients with ILD had resolution of pulmonary disorders, whereas 25% experienced ILD deterioration. Morbidity and mortality rates were as high as 13.9% and 36.4%, respectively, in PM/DM patients with ILD. Parameters of PM/DM that related to ILD poor outcome were identified as follows: Hamman-Rich-like pattern, initial diffusing capacity of carbon monoxide <45%, neutrophil alveolitis, and histologic usual interstitial pneumonia. Additionally, for the group with ILD, polyarthritis, higher values of erythrocyte sedimentation rate and C-reactive protein, presence of anti-Jo-1 antibody, and characteristic microangiopathy were significantly more frequent.

CONCLUSIONS

Our series underlines the high frequency of ILD in PM/DM patients, resulting in increased morbidity and mortality rates. It also indicates that PM/DM patients should routinely be screened for ILD, even those patients without anti-Jo-1 antibody, because 69% of our ILD patients were seronegative for the anti-Jo-1 antibody. Our findings further suggest that PM/DM patients presenting with factors predictive of ILD poor outcome may require more aggressive therapy.

Pubmed
Journal: Journal of immunology (Baltimore, Md. : 1950)
November/26/2002
Abstract

BLyS and APRIL are two members of the TNF superfamily that are secreted by activated myeloid cells and have costimulatory activity on B cells. BLyS and APRIL share two receptors, TACI and BCMA, whereas a third receptor, BAFF-R, specifically binds BLyS. Both BLyS and APRIL have been described as homotrimeric molecules, a feature common to members of the TNF superfamily. In this study, we show that APRIL and BLyS can form active heterotrimeric molecules when coexpressed and that circulating heterotrimers are present in serum samples from patients with systemic immune-based rheumatic diseases. These findings raise the possibility that active BLyS/APRIL heterotrimers may play a role in rheumatic and other autoimmune diseases and that other members of the TNF ligand superfamily may also form active soluble heterotrimers.

Pubmed
Journal: Annals of internal medicine
June/27/2001
Abstract

BACKGROUND

The validity and magnitude of an association between myositis and malignant disease continue to be debated. Such issues as the legitimacy of a myositis diagnosis and distinction among myositis subgroups in previous population-based studies remain unresolved.

OBJECTIVE

To determine the risk for malignant disease in patients with biopsy-proven inflammatory myopathies.

METHODS

Population-based, retrospective cohort study.

METHODS

Victoria, Australia.

METHODS

537 patients in whom a biopsy-positive idiopathic inflammatory myopathy was first diagnosed from 1981 through 1995.

METHODS

Standardized incidence ratios were calculated to compare the incidence of malignant disease in patients with inflammatory myopathy and the general population.

RESULTS

A total of 116 cases of malignant disease were found in 104 patients. Seventy-four cases were identified concurrently with (within 7 days) or after diagnosis of myositis. The highest risk for malignant disease was associated with dermatomyositis (standardized incidence ratio, 6.2 [95% CI, 3.9 to 10.0]). The risk was also increased in polymyositis (standardized incidence ratio, 2.0 [CI, 1.4 to 2.7]), although the relative risk for malignant disease in dermatomyositis compared with polymyositis was 2.4 (CI, 1.3 to 4.2). An increased risk for malignant disease was also found in inclusion-body myositis (standardized incidence ratio, 2.4 [CI, 1.2 to 4.9]). The excess risk for malignant disease diminished with time (standardized incidence ratio, 4.4 [CI, 2.7 to 7.1] in the first year; 3.4 [CI, 2.3 to 5.1] between 1 and 3 years; 2.2 [CI, 1.3 to 3.9] between 3 and 5 years; and 1.6 [CI, 1.0 to 2.6] beyond 5 years [ P for trend, 0.002]).

CONCLUSIONS

The risk for malignant disease is increased in biopsy-proven dermatomyositis and polymyositis and also appears to be increased in inclusion-body myositis.

Pubmed
Journal: Annals of the rheumatic diseases
December/14/2008
Abstract

OBJECTIVE

To investigate the effect of the tumour necrosis factor (TNF) blocking agent infliximab in patients with treatment-resistant inflammatory myopathies.

METHODS

A total of 13 patients with refractory polymyositis (PM), dermatomyositis (DM), or inclusion body myositis (IBM) were treated with 4 infliximab infusions (5 mg/kg body weight) over 14 weeks. Outcome measures included myositis disease activity score with improvement defined according to The International Myositis Assessment and Clinical Studies Group (IMACS), and MRI. Repeated muscles biopsies were investigated for cellular infiltrates, major histocompatibility complex (MHC) class I and II, TNF, interleukin (IL)1alpha, IL6, high mobility group box chromosomal protein 1 (HMGB-1), interferon gamma (IFNgamma), myxovirus resistance protein A (MxA) and membrane attack complex (MAC) expression. Type I IFN activity was analysed in sera.

RESULTS

Nine patients completed the study. Three patients discontinued due to adverse events and one due to a discovered malignancy. Three of the completers improved by >or=20% in three or more variables of the disease activity core set, four were unchanged and two worsened >or=30%. No patient improved in muscle strength by manual muscle test. At baseline, two completers had signs of muscle inflammation by MRI, and five at follow-up. T lymphocytes, macrophages, cytokine expression and MAC deposition in muscle biopsies were still evident after treatment. Type I IFN activity was increased after treatment.

CONCLUSIONS

Infliximab treatment was not effective in refractory inflammatory myopathies. In view of radiological and clinical worsening, and activation of the type I IFN system in several cases, infliximab is not an alternative treatment in patients with treatment-resistant myositis.

Pubmed
Journal: Arthritis and rheumatism
May/28/1997
Abstract

OBJECTIVE

To study cytokine expression in muscle tissues of patients with inflammatory myopathies and to compare the profiles of patients with polymyositis (PM), inclusion body myositis (IBM), and dermatomyositis (DM).

METHODS

We performed indirect immunohistochemistry studies of muscle tissue sections with a panel of 16 different cytokine-specific monoclonal antibodies, directed against interleukin-1alpha, (IL-1alpha), IL-1beta, IL-1 receptor antagonist (IL-1Ra), IL-2, IL-3, IL-4, IL-6, IL-8, IL-10, IL-13, interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), transforming growth factor beta1 (TGF beta1), TGF beta2, and TGF beta3 in 5 untreated patients each with PM, DM, and IBM and in 4 normal controls. Fresh frozen muscle tissue sections were fixed in formaldehyde before the procedure. The use of saponin as a detergent to permeabilize the cell membranes enabled identification of intracellular cytokine production.

RESULTS

The most prominent finding was the expression of IL-1alpha observed in all patients but in none of the normal controls. In all patients with PM, DM, and IBM, IL-1alpha was expressed in endothelial cells of capillaries, arterioles, and venules in areas surrounded by inflammatory cells, and also in areas with no or scarce inflammatory cells in both endomysium and perimysium. Furthermore, IL-1alpha was also expressed in mononuclear inflammatory cells in all 15 cases. IL-1beta was observed in inflammatory cells in 10 of the 15 patients but, in contrast to IL-1alpha, it was not expressed in blood vessel walls. TGF beta1, TGF beta2, and TGF beta3 were strongly positive in all 15 patients, but only scattered cells were positive in the normal controls. The remaining cytokines were observed only in relatively few cells and only in occasional patients (although the patients were selected for the presence of large infiltrates), and in none of the controls. The patterns were similar in PM, DM, and IBM.

CONCLUSIONS

Cytokine expression in muscle tissue of patients with inflammatory myopathy is dominated by IL-1alpha, IL-1beta, and TGF beta1-3. The predominant IL-1alpha expression in the blood vessels indicates an importance of the endothelial cells in the inflammatory process in PM, IBM, and DM. A sustained, local release of T cell-derived cytokines may not be a requirement for tissue injury in the inflammatory myopathies. There does not appear to be a qualitative difference in cytokine expression patterns in PM, IBM, and DM.

Pubmed
Journal: Annals of the rheumatic diseases
December/13/2006
Abstract

OBJECTIVE

To elucidate the clinical importance of the anti-signal recognition particle (SRP) autoantibody in patients with myositis.

METHODS

Retrospective systematic assessment of the clinical, laboratory and histological characteristics of 23 anti-SRP-positive patients from six European centres. Data were compared with a large group of anti-SRP-negative patients with myositis published previously.

RESULTS

Clinically, patients with anti-SRP autoantibodies often had a severe symmetric proximal muscle weakness resulting in marked disability, dysphagia and highly elevated levels of serum creatine kinase. Three patients had typical dermatomyositis rashes. The disease was associated with the occurrence of extramuscular signs and symptoms including interstitial lung disease. No association was found with an increased risk of cardiac involvement, and the disease carried a reasonably favourable prognosis with most patients responding to treatment. None of the patients had the typical histological features of myositis. Most muscle biopsy specimens showed the presence of necrotic muscle fibres and no inflammatory infiltrates.

CONCLUSIONS

Anti-SRP autoantibodies are associated with a syndrome of a necrotising myopathy in the spectrum of immune-mediated myopathies that differs from typical polymyositis. Further studies are needed to elucidate the pathogenesis and to clarify the role of the anti-SRP autoantibodies in this unique disease.

Pubmed
Journal: Rheumatology (Oxford, England)
February/27/2002
Abstract

OBJECTIVE

To assess the long-term outcome of a cohort of 46 patients with idiopathic myositis by assessing both health status, as measured by the SF-36, and cumulative survival probability over a 20-yr follow-up period at a single rheumatology centre. Methods and results. Forty-six patients under long-term follow-up from 1978 to 1999 were identified from our database. All patients fulfilled three out of four of the Bohan and Peter criteria for myositis. We excluded those with malignancy-associated disease and those with inclusion body myositis. Twenty-three patients (50%) had adult-onset polymyositis, 14 (30.4%) had adult-onset dermatomyositis, one had childhood-onset dermatomyositis and eight (17.4%) had an overlap syndrome (associated with either systemic lupus erythematosus or rheumatoid arthritis). During the course of the disease, seven patients (15.2%) went into full remission, eight (17.4%) had monophasic illness, nine (19.6%) had a relapsing-remitting course, 16 (34.8%) had chronic progressive illness and six (13.04%) died. All patients had significantly lower SF-36 scores in all aspects of health compared with the general population (P< or =0.001). Patients with chronic progressive illness had significantly greater bodily pain (P< or =0.05, t-test) than those with a relapsing-remitting illness, but did not differ in other aspects of health. There was no significant difference in the scores in the different domains of the SF-36 between the patients with active disease and those with inactive disease (0.05<P<0.1). Six of the 46 patients died. Cumulative survival probability was calculated. The five-year survival rate was 95% and the 10-yr survival rate 83.8%.

CONCLUSIONS

Patients with myositis report significantly poorer health compared with the general population. Health status and disease activity are important outcome measures in the assessment of patients with myositis.

Pubmed
Journal: Brain : a journal of neurology
June/15/2008
Abstract

Distinct interrelationships between inflammation and beta-amyloid-associated degeneration, the two major hallmarks of the skeletal muscle pathology in sporadic inclusion body myositis (sIBM), have remained elusive. Expression of markers relevant for these pathomechanisms were analysed in biopsies of sIBM, polymyositis (PM), dermatomyositis (DM), dystrophic and non-myopathic muscle as controls, and cultured human myotubes. By quantitative PCR, a higher upregulation was noted for the mRNA-expression of CXCL-9, CCL-3, CCL-4, IFN-gamma, TNF-alpha and IL-1 beta in sIBM muscle compared to PM, DM and controls. All inflammatory myopathies displayed overexpression of degeneration-associated markers, yet only in sIBM, expression of the mRNA of amyloid precursor protein (APP) significantly and consistently correlated with inflammation in the muscle and mRNA-levels of chemokines and IFN-gamma. Only in sIBM, immunohistochemical analysis revealed that inflammatory mediators including IL-1 beta co-localized to beta-amyloid depositions within myofibres. In human myotubes, exposure to IL-1 beta caused upregulation of APP with subsequent intracellular aggregation of beta-amyloid. Our data suggest that, in sIBM muscle, production of high amounts of pro-inflammatory mediators specifically induces beta-amyloid-associated degeneration. The observations may help to design targeted treatment strategies for chronic inflammatory disorders of the skeletal muscle.

Pubmed
Journal: Acta neuropathologica
August/20/2009
Abstract

p62, also known as sequestosome1, is a shuttle protein transporting polyubiquitinated proteins for both the proteasomal and lysosomal degradation. p62 is an integral component of inclusions in brains of various neurodegenerative disorders, including Alzheimer disease (AD) neurofibrillary tangles (NFTs) and Lewy bodies in Parkinson disease. In AD brain, the p62 localized in NFTs is associated with phosphorylated tau (p-tau). Sporadic inclusion-body myositis (s-IBM) is the most common progressive muscle disease associated with aging, and its muscle tissue has several phenotypic similarities to AD brain. Abnormal accumulation of intracellular multiprotein inclusions, containing p-tau in the form of paired helical filaments, amyloid-beta, and several other "Alzheimer-characteristic proteins", is a characteristic feature of the s-IBM muscle fiber phenotype. Diminished proteasomal and lysosomal protein degradation appear to play an important role in the formation of intra-muscle-fiber inclusions. We now report that: (1) in s-IBM muscle fibers, p62 protein is increased on both the protein and the mRNA levels, and it is strongly accumulated within, and as a dense peripheral shell surrounding, p-tau containing inclusions, by both the light- and electron-microscopy. Accordingly, our studies provide a new, reliable, and simple molecular marker of p-tau inclusions in s-IBM muscle fibers. The prominent p62 immunohistochemical positivity and pattern diagnostically distinguish s-IBM from polymyositis and dermatomyositis. (2) In normal cultured human muscle fibers, experimental inhibition of either proteasomal or lysosomal protein degradation caused substantial increase of p62, suggesting that similar in vivo mechanisms might contribute to the p62 increase in s-IBM muscle fibers.

Pubmed
Journal: Annals of the rheumatic diseases
October/28/2007
Abstract

OBJECTIVE

There is a known association between myositis and cancer. The risk is greater in dermatomyositis (DM) than polymyositis (PM), although reliable methods to predict cancer risk in specific patients with myositis are not presently available. This study was undertaken to determine whether risk of developing cancer in myositis can be predicted by antibody profiling.

METHODS

A cross-sectional study of UK Caucasian adults with PM (n = 109), DM (n = 103) and connective tissue disease overlap (myositis/CTD-overlap, n = 70). Patients were tested for a comprehensive range of myositis-specific/associated autoantibodies. Sensitivity and specificity analyses were performed for the optimal identification of cancer risk.

RESULTS

Sixteen patients had cancer-associated myositis (CAM) (15 DM, 1 myositis/CTD-overlap). CAM patients were older at disease onset, and patients without myositis-specific/associated autoantibodies on "routine" laboratory testing (negative for anti-Jo-1, anti-PM-Scl, anti-U1-RNP, anti-U3-RNP, anti-Ku antibodies) had a significantly increased risk of CAM. Possession of the antibody against 155 kDa and 140 kDa protein specificities (anti-155/140 antibody) represented a significant risk factor for CAM, and was found exclusively in DM. A positive anti-155/140 antibody result proved highly specific, moderately sensitive, with high negative predictive value for CAM. A "negative routine myositis antibody panel" result was highly sensitive, with high negative predictive value for CAM. The combination of these two approaches was 94% sensitive, detecting 15 of 16 CAM, with 100% sensitivity and negative predictive value in DM.

CONCLUSIONS

These results may help clinicians predict which patients with myositis are at greater risk of developing cancer, thus identifying those requiring aggressive diagnostic evaluation and intensive cancer surveillance at myositis onset and follow-up.

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