Eleven patients met rigid criteria for having both polymyositis and systemic lupus erythematosus (SLE). The patients differed little in clinical features when compared with patients who had SLE and polymyositis in a previously reported series. The overall mortality rate of 18% and the finding that 56% of survivors were asymptomatic at latest follow-up (average four years) suggest that the prognosis for this subgroup of patients may be more favorable than that for patients with rheumatoid arthritis and scleroderma complicated by polymyositis and may be comparable to the prognosis of the overall group of patients with polymyositis.

Fibromyalgia (FM) is a common rheumatologic disorder characterised by widespread muscular pain. Myalgia is also a common clinical feature in Connective Tissue Disease (CTD), and FM should be studied for the concomitant presence of a CTD. The aim of this study is to evaluate the prevalence of Myositis-Specific and Myositis-Associated Antibodies (MSA/MAA) in a cohort of FM patients. We enrolled 233 consecutive FM patients (defined according to the 2016 criteria) that did not report clinical signs of autoimmune disorders and followed them for at least one year. The patients were tested for MSA/MAA with immunoblotting. FM patients were seropositive for Antinuclear Antibodies (ANA) in 24% of cases, for MSA in 9%, and for MAA in 6%. A specific diagnosis of CTD was made in 12 patients (5.2%), namely, 5 cases of primary Sjögren's Syndrome and 7 of Idiopathic Inflammatory Myopathy. Seropositive patients showed clinical features similar to those who were seronegative at baseline. A CTD diagnosis was associated with ANA positivity (p = 0.03, X2 4.9), the presence of a speckled pattern (p = 0.02, X2 5.3), positivity for MAA (p = 0.004, X2 8.1), and MSA (p = 0.003, X2 9.2). In conclusion, a non-negligible proportion of FM patients may be seropositive for MSA/MAA, and that seropositivity might suggest a diagnosis of CTD.

No abstract available

To determine the specificity of myositis-specific autoantibodies (MSAs) for autoimmune myopathy compared with inherited muscle diseases.

The purpose of this paper is to comprehensively evaluate secondary causes of inflammatory myopathies (myositis) and to review treatment options.

The purpose of this review was to give an update on treatment modalities for patients with idiopathic inflammatory myopathies, or shortly myositis, excluding the subgroup inclusion body myositis, based on a literature survey on therapies used in myositis. Few controlled trials have been performed in patients with myositis; therefore, we also included a summary of open-label trials, case series, and case reports.

HLA genes are a major genetic risk factor for myositis and myositis specific antibodies (MSAs), exhibiting unique HLA backgrounds for myositis in different ethnic groups. This is the first large scale Korean study to genotype the HLA-DRB1 and -DPB1 alleles and to examine their association with myositis and MSAs.

Myositis is a heterogeneous family of autoimmune muscle diseases. As myositis autoantibodies recognize intracellular proteins, their role in disease pathogenesis has been unclear. This study aimed to determine whether myositis autoantibodies reach their autoantigen targets within muscle cells and disrupt the normal function of these proteins.

The aim of this study was to investigate HLA class II associations in polymyositis (PM) and dermatomyositis (DM), and to determine how these associations influence clinical and serological differences. DNA samples were obtained from 225 UK Caucasian idiopathic inflammatory myopathy patients (PM = 117, DM = 108) and compared with 537 randomly selected UK Caucasian controls. All cases had also been assessed for the presence of related malignancy and interstitial lung disease (ILD), and a number of myositis-specific/myositis-associated antibodies (MSAs/MAAs). Subjects were genotyped for HLA-DRB1, DQA1 and DQB1. HLA-DRB1*03, DQA1*05 and DQB1*02 were associated with an increased risk for both PM and DM. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype demonstrated strong association with ILD, irrespective of myositis subtype or presence of anti-aminoacyl-transfer RNA synthetase antibodies. The HLA-DRB1*07-DQA1*02-DQB1*02 haplotype was associated with risk for anti-Mi-2 antibodies, and discriminated PM from DM (odds ratio 0.3, 95% confidence interval 0.1-0.6), even in anti-Mi-2 negative patients. Other MSA/MAAs showed specific associations with other HLA class II haplotypes, irrespective of myositis subtype. There were no genotype, haplotype or serological associations with malignancy. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype associations appear to not only govern disease susceptibility in Caucasian PM/DM patients, but also phenotypic features common to PM/DM. Though strongly associated with anti-Mi-2 antibodies, the HLA-DRB1*07-DQA1*02-DQB1*02 haplotype shows differential associations with PM/DM disease susceptibility. In conclusion, these findings support the notion that myositis patients with differing myositis serology have different immunogenetic profiles, and that these profiles may define specific myositis subtypes.

Association between cancer and myositis has been extensively reported and malignancy is a potentially life-threating complication in myositis. In this retrospective study authors give an overview of Hungarian cancer-associated myositis (CAM) patients treated at a single centre managing 450 myositis patients. All patients were diagnosed according to Bohan and Peter. Statistical analysis of disease onset, age, sex, muscle, skin and extramuscular symptoms, muscle enzymes, presence of antibodies, treatment and prognosis was performed. 43 patients could be considered as having CAM. 83.72% had cancer within one year of diagnosis of myositis. Most common localizations were ductal carcinoma of breast and adenocarcinoma of lung. Significant differences were observed between CAM and the non-CAM control patients: DM:PM ratio was 2.31:1 vs. 0.87:1, respectively (p = 0.029), age at diagnosis was 56.60 ± 12.79 vs. 38.88 ± 10.88 years, respectively (p < 0.001). Tumour-treatment was the following: surgical removal in 55.81%, chemotherapy in 51.1%, radiotherapy in 39.53%, hormone treatment in 18.6%, combination therapy in 51.16% of patients. Muscle enzyme levels of patients undergoing surgery were significantly reduced after intervention. 36 patients died (83.72%); 25 DM (83.33%) and 11 PM patients (84.62%); 5 years survival was 15.4% for PM and 27.5% for DM. This study demonstrates that DM, distal muscle weakness, asymmetric Raynaud's phenomenon, older age, ANA-negativity are risk factors for developing malignancy and polymyositis patients have less chance of long-lasting survival. It is very important to think about cancer and follow every single myositis patient in the clinical routine because survival rate of CAM is very poor.

Inclusion body myositis (IBM) is usually associated with a large number of cytochrome c oxidase (COX)-deficient muscle fibers and acquired mitochondrial DNA (mtDNA) deletions. We studied the number of COX-deficient fibers and the amount of mtDNA deletions, and if variants in nuclear genes involved in mtDNA maintenance may contribute to the occurrence of mtDNA deletions in IBM muscle. Twenty-six IBM patients were included. COX-deficient fibers were assayed by morphometry and mtDNA deletions by qPCR. POLG was analyzed in all patients by Sanger sequencing and C10orf2 (Twinkle), DNA2, MGME1, OPA1, POLG2, RRM2B, SLC25A4 and TYMP in six patients by next generation sequencing. Patients with many COX-deficient muscle fibers had a significantly higher proportion of mtDNA deletions than patients with few COX-deficient fibers. We found previously unreported variants in POLG and C10orf2 and IBM patients had a significantly higher frequency of an RRM2B variant than controls. POLG variants appeared more common in IBM patients with many COX-deficient fibers, but the difference was not statistically significant. We conclude that COX-deficient fibers in inclusion body myositis are associated with multiple mtDNA deletions. In IBM patients we found novel and also previously reported variants in genes of importance for mtDNA maintenance that warrants further studies.

Inclusion body myositis is an increasingly recognised form of inflammatory myopathy with characteristic clinical and histopathological features which has seldom been reported in the United Kingdom. This paper presents the clinicopathological features of a series of patients diagnosed in Nottingham from 1986 to 1990. During this period, 1319 muscle biopsy samples were processed by this laboratory and rimmed vacuoles were seen in 17 patients. Eleven patients had definite or probable inclusion body myositis according to published criteria. The mean age of the group was 69.4 years with a male to female ratio of 8:3. Typical clinical features were a slowly progressive painless, proximal lower limb weakness, with muscle wasting and early loss of reflexes. The median duration of illness from first symptom to presentation was five years (range 2-18 years). Falls were a prominent symptom in six patients and distal weakness occurred in nine patients. Creatine kinase was increased in 10 patients but only one had a level > 1000 IU/l; the erythrocyte sedimentation rate was normal in five patients. Treatment with steroids or cytotoxic drugs, or both, did not prevent disease progression. It is confirmed that inclusion body myositis is a distinct cause of inflammatory myopathy which is probably underdiagnosed in the United Kingdom. Clinically, it should be suspected in older patients presenting with muscle weakness of insidious onset. Pathologically, a careful search should be made for rimmed vacuoles and inflammation; ultrastructurally, the presence of inclusions will confirm the diagnosis.

Inclusion body myositis (IBM) is characterized by a combination of inflammatory and degenerative changes affecting muscle. While the primary cause of IBM is unknown, genetic factors may influence disease susceptibility. To determine genetic factors contributing to the etiology of IBM, we conducted the largest genetic association study of the disease to date, investigating immune-related genes using the Immunochip.

Sporadic inclusion body myositis (s-IBM) is the most commonly occurring acquired inflammatory myopathy in elderly people (>45 years); however, pathogenic mechanisms are poorly understood and diagnostic tools are limited. In view of this, new therapeutic and diagnostic molecular markers for s-IBM need to be identified.

The Phylum Microsporidia comprises >1,200 species, only 15 of which are known to infect humans, including the genera Trachipleistophora, Pleistophora, and Brachiola. We report an infection by Tubulinosema sp. in an immunosuppressed patient.

Idiopathic inflammatory myopathies represent a heterogeneous group of autoimmune diseases with systemic involvement. Even though numerous specific autoantibodies have been recognized, they have not been included, with the only exception of anti-Jo-1, into the 2017 Classification Criteria, thus perpetuating a clinical-serologic gap. The lack of homogeneous grouping based on the antibody profile deeply impacts the diagnostic approach, therapeutic choices and prognostic stratification of these patients. This review is intended to highlight the comprehensive scenario regarding myositis-related autoantibodies, from the molecular characterization and biological significance to target antigens, from the detection tools, with a special focus on immunofluorescence patterns on HEp-2 cells, to their relative prevalence and ethnic diversity, from the clinical presentation to prognosis. If, on the one hand, a notable body of literature is present, on the other data are fragmented, retrospectively based and collected from small case series, so that they do not sufficiently support the decision-making process (i.e. therapeutic approach) into the clinics.

As treatment of refractory idiopathic inflammatory myopathies (IIM) has been challenging, there is growing interest in assessing new therapies that target various pathways implicated in the pathogenesis of IIM. In the largest clinical trial to date, rituximab was studied in adult and juvenile myositis, but the primary outcome was not met despite 83 percent of subjects with refractory myositis meeting the definition of improvement. The U.S. Food and Drug Administration (FDA) has recently granted approval to Octagam 10% immune globulin intravenous (IVIg), for the treatment of adult dermatomyositis based on impressive results from a double-blind placebo-controlled trial. Anti-tumor necrosis factor (anti-TNF) utility in IIM is not recommended and recent reports suggest this therapy may induce systemic autoimmune disease including myositis. Further, anti-IL6 therapy cannot be recommended as a recent trial of tocilizumab failed to reach its primary endpoint. Further studies are needed to assess the role of newer therapies such as abatacept (inhibition of T cell co-stimulation), sifalimumab (anti-IFNα), Janus kinase [JAK] inhibitors, apremilast (phosphodiesterase 4 inhibitor), and KZR-616 (selective inhibitor of the immunoproteasome) given their biological plausibility and encouraging recent small-case series results. The future of IIM therapy will depend on exploring biomarkers implicated in the etiopathogenesis of IIM, improvements in myositis classification based on serological and histopathological features, and well-designed controlled clinical trials using validated consensus outcome measures.

Eosinophilic myositis belong to the idiopathic inflammatory myopathies and are defined by an inflammatory infiltrate composed of eosinophils within the muscle. To date, no consensus exists for diagnosis and care of such patients. The aim of this review was to describe clinical and histological presentation, treatment, and outcome of eosinophilic myositis based on a systematic review of all published histologically proven cases of eosinophilic myositis. A total of 453 records were identified in MEDLINE until November 2020. A total of 69 published cases were identified. The analysis of these allowed the distinction of the 3 previously described pathological subtypes: focal eosinophilic myositis (n = 17); diffuse eosinophilic myositis (n = 36); and eosinophilic perimyositis (n = 16). We propose a simple algorithm for diagnosis and treatment strategy for the care of patient with muscular symptoms and blood eosinophilia. This work also highlights eosinophilic myositis pathogenesis and the need for careful investigations in order to rule out differential diagnoses.

We developed an experimental autoimmune myositis (EAM) mouse model of polymyositis where we outlined the role of regulatory T (Treg) cells. Rapamycin, this immunosuppressant drug used to prevent rejection in organ transplantation, is known to spare Treg. Our aim was to test the efficacy of rapamycin in vivo in this EAM model and to investigate the effects of the drug on different immune cell sub-populations.

Leukocyte infiltration plays an important role in the pathogenesis and progression of myositis, and is highly associated with disease severity. Currently, there is a lack of: efficacious therapies for myositis; understanding of the molecular features important for disease pathogenesis; and potential molecular biomarkers for characterizing inflammatory myopathies to aid in clinical development.