Idiopathic inflammatory myositis is associated with a high incidence of hypertension and diabetes mellitus

Aims: The long‐terms complications of immunosuppressive and anti‐inflammatory treatment in idiopathic inflammatory myositis (IIM) are unknown. We sought to determine the complications of these treatments in a large cohort of patients with biopsy‐proven IIM. Methods: A South Australian database for patients with biopsy‐proven IIM was established. Clinical details of patients including treatment received were recorded. Results: Forty‐three patients with dermatomyositis (DM), 184 with polymyositis (PM) and 117 with inclusion body myositis (IBM) were registered on the database. The prevalence of hypertension and diabetes in this population was 62% and 29%, respectively, considerably higher than the background prevalence of 9.4% and 4%, making detection of treatment‐related adverse effects difficult. Hypertension and ischemic heart disease were more likely to be present prior to the diagnosis of IIM rather than following it. Hypertension and diabetes occurred more frequently following the diagnosis of myositis, in patients with DM compared with PM or IBM. Conclusions: We report a novel association of IIM with hypertension, diabetes and ischemic heart disease, indicating that a comprehensive assessment of vascular risk factors is essential in IIM.     

Have recent immunogenetic investigations increased our understanding of disease mechanisms in the idiopathic inflammatory myopathies?

PURPOSE OF REVIEW: The idiopathic inflammatory myopathies (IIM) continue to provide a challenge given the variable effectiveness of the available treatments, and immunogenetic studies are ongoing to further elucidate IIM disease mechanisms. This review examines how recent research has improved our understanding of the mechanisms that lead to IIM. RECENT FINDINGS: HLA-DRB1 studies in a large homogenous cohort of UK Caucasian patients have confirmed that polymyositis (PM) and dermatomyositis (DM) are not genetically identical diseases while other studies have shown that tumor necrosis factor alpha is genetically implicated in disease susceptibility. Some remarkable results from an international collaboration, correlating gene-environment interactions, clearly suggest that ultraviolet light is capable of modulating both clinical and immunologic features of IIMs. Studies on microchimerism are unraveling interesting associations in juvenile DM patients, and bolstering the hypothesis that myositis may be an 'allo-immune' disease. mRNA gene expression profiling is helping to increase our understanding of myositis pathogenesis, whilst animal models have provided new information on the roles of Th1 responses and nitric oxide synthase in muscle disease. New candidate genes have been examined in inclusion body myositis (IBM), and a novel gene transfer experiment has been conducted, which led to significant changes in expression of the IBM phenotype. SUMMARY: Improving the understanding of the immunogenetics and immunopathogenesis of the IIMs may in the future provide novel therapeutic targets, and thus improve outcomes in these difficult diseases.     

Immunogenetic risk and protective factors for the idiopathic inflammatory myopathies: distinct HLA-A, -B, -Cw, -DRB1 and -DQA1 allelic profiles and motifs define clinicopathologic groups in caucasians

The idiopathic inflammatory myopathies (IIM) are systemic connective tissue diseases in which autoimmune pathology is suspected to promote chronic muscle inflammation and weakness. We have performed low to high resolution genotyping to characterize the allelic profiles of HLA-A, -B, -Cw, -DRB1, and -DQA1 loci in a large population of North American Caucasian patients with IIM representing the major clinicopathologic groups (n = 571). We confirmed that alleles of the 8.1 ancestral haplotype were important risk markers for the development of IIM, and a random forests classification analysis suggested that within this haplotype, HLA-B*0801, DRB1*0301 and/ or closely linked genes are the principal HLA risk factors. In addition, we identified several novel HLA factors associated distinctly with 1 or more clinicopathologic groups of IIM. The DQA1*0201 allele and associated peptide-binding motif (KLPLFHRL) were exclusive protective factors for the CD8+ T cell-mediated IIM forms of polymyositis (PM) and inclusion body myositis (IBM) (pc < 0.005). In contrast, HLA-A*68 alleles were significant risk factors for dermatomyositis (DM) (pc = 0.0021), a distinct clinical group thought to involve a humorally mediated immunopathology. While the DQA1*0301 allele was detected as a possible risk factor for IIM, PM, and DM patients (p < 0.05), DQA1*03 alleles were protective factors for IBM (pc = 0.0002). Myositis associated with malignancies was the most distinctive group of IIM wherein HLA Class I alleles were the only identifiable susceptibility factors and a shared HLA-Cw peptide-binding motif (AGSHTLQWM) conferred significant risk (pc = 0.019). Together, these data suggest that HLA susceptibility markers distinguish different myositis phenotypes with divergent pathogenetic mechanisms. These variations in associated HLA polymorphisms may reflect responses to unique environmental triggers resulting in the tissue pathospecificity and distinct clinicopathologic syndromes of the IIM.     

The role of cytokines, chemokines, and adhesion molecules in the pathogenesis of idiopathic inflammatory myopathies

Cytokines, chemokines, and adhesion molecules are important mediators in chronic inflammation and in immune regulation. In idiopathic inflammatory myopathies (IIM), increased expression of proinflammatory cytokines particularly interleukin (IL)-1a and IL-1b, tumor necrosis factor (TNF)-a and macrophage inflammatory proteins (MIP)-1a, as well as of the inhibitory cytokines transforming growth factor (TGF)-b was observed in muscle. There was no difference in cytokine and chemokine pattern between polymyositis, dermatomyositis, and inclusion body myositis, which could indicate that similar pathogenetic mechanisms are involved in these subsets of myositis. A prominent finding of IL-1a expression in endothelial cells, both in patients with active inflammtion and in patients with chronic persisting muscle weakness without inflammation, makes this an interesting molecule in understanding the mechanisms for the pathogenesis of muscle weakness. Involvement of the blood vessels in the pathogenesis of myositis was further supported by increased expression of adhesion molecules and by a phenotypical expression of endothelial cells, resembling high endothelium venules in all three subsets of IIM. The molecular studies to date indicate a role of the microvessels in the pathogenesis of IIM not only in DM, as was previously suggested, but also in PM and IBM. The studies also indicate that IL-1a could be a target molecule for new therapeutical interventions.     

A three-way interplay of DR4, autoantibodies and synovitis in biopsy-proven idiopathic inflammatory myositis

The aim of this study was to determine the HLA and autoantibody associations of patients with histologically confirmed idiopathic inflammatory myositis (IIM). Serum and DNA were archived from South Australian patients with biopsy-proven dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). HLA typing for Class I and II alleles was performed by serology and DNA-based technology, respectively, for 133 myositis patients and 166 Caucasian population-based controls. Myositis-specific and myositis-associated autoantibodies were detected by line immunoblot. All alleles of the 8.1AH were associated with myositis susceptibility. The B8-DR3 haplotype fragment conferred the strongest susceptibility (OR 2.9, 95% CI 1.8–4.6), and the B-DR region of other ancestral haplotypes was associated with myositis subgroups. Autoantibodies were present in 42/130 (32%) IIM patients and were more frequent in DM (11/17, 65%) than PM (23/70, 33%) or IBM (8/43, 19%), P = 0.002. Autoantibodies were associated with DRB1*03 (P = 0.0005) but also with DRB1*04 (P = 0.004). The frequency of autoantibodies in the three myositis subgroups mirrored the frequency of DR4. Polyarthralgia (±synovitis) was more common in DM/PM (30/76, 39%) than IBM (3/32, 9%), P = 0.004, and there was a strong ordinal association between the prevalence of autoantibodies and polyarthralgia ± synovitis (proportional OR = 5.5, 95% CI 2.3–13.7, P = 0.0004). The central MHC region confers the strongest susceptibility for IIM and also modulates disease phenotype. Our findings reveal a novel association of autoantibodies with DR4 and with arthralgia/synovitis in IIM and raise the possibility of a genetically (DR4) determined citrullination of myositis autoantigens expressed in muscle and synovium.     

溃疡性结肠炎易感基因的研究进展

溃疡性结肠炎(ulcerative colitis,UC)是一种病因不明的肠道慢性炎症性疾病,目前较为一致的观点认为,UC是携带易感基因的个体在环境因素的作用下,自身免疫功能紊乱所引发的一种肠道非特异性炎症性疾病.其发病的种族地理差异、单卵双生子的高共患率和家族聚集现象,提示遗传因素在UC发病中起重要作用.目前已发现许...     

Myositis: an update on pathogenesis

PURPOSE OF REVIEW: The etiology and much about the pathogenesis of the inflammatory myopathies remain a mystery. In this review, we investigate recent research efforts to understand the pathogenesis of the diverse entities of polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM), diseases that result from interactions between environmental risk factors and genetic susceptibility. RECENT FINDINGS: Over the past year, there has been considerable progress toward better understanding of IBM, with relatively few developments toward understanding PM and DM. Although these diseases may share some common clinical phenotypic and serologic components, they differ on a molecular and cellular level. SUMMARY: The need for definitive, safer therapies in these diseases makes vital the search for defining detailed pathogenesis of inflammation and muscle fiber damage at the molecular level.     

Incidence and prevalence of idiopathic inflammatory myopathies in South Australia: a 30‐year epidemiologic study of histology‐proven cases

Aim: To describe the epidemiology of biopsy‐proven idiopathic inflammatory myopathies (IIM) in South Australia (SA). Methods: Cases of IIM were ascertained by review of all muscle biopsy reports from the Neuropathology Laboratory, Hanson Institute (wherein all adult muscle biopsies in SA are reported) from 1980 to 2009. Clinical correlation of these patients by review of medical records was undertaken. SA population denominator numbers were obtained from the Australian Bureau of Statistics. Results: Three hundred and fifty‐two biopsy‐proven cases of IIM were identified between 1980 and 2009. The overall annual incidence of IIM appeared to be rising with a mean incidence of eight cases per million population (95% CI: 7.2–8.9). This corresponded with an increasing annual incidence of inclusion body myositis (IBM) (prevalence of 50.5 cases per million population in 2009, 95% CI: 40.2–62.7). A female preponderance was noted in both dermatomyositis (DM) (F : M = 2.75 : 1.00) and polymyositis (PM) (F : M = 1.55 : 1.00) but gender distribution was almost equal in IBM (F : M = 1.1 : 1.0). Mean age at diagnosis for IBM (67.5 years) was higher than for DM (55.1 years) and PM (59.0 years). A higher proportion of DM patients reported living in urban dwellings and DM patients tended to be predominantly professionals. Conclusions: In SA there is an increasing incidence of IBM and the prevalence is one of the highest reported to date. This may reflect an increase in the number of biopsies performed, improved histological techniques or a genuine increase in incidence.     

Possible future avenues for myositis therapeutics: DM,IMNM and IBM

Idiopathic inflammatory myopathies (IIMs) represent a heterogeneous group of systemic autoimmune diseases characterized by immune-mediated muscle injury. As insights into pathogenesis of IIM evolve, novel therapeutic strategies have become available to optimize outcomes. Herein, we summarize novel and emerging strategies in the management of dermatomyositis (DM), immunemediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM).     

Dermatomyositis and polymyositis: new treatment targets on the horizon

Polymyositis (PM) and dermatomyositis (DM) are rare idiopathic inflammatory myopathies (IIM) with a presumed autoimmune pathogenesis. Typical features are subacute onset, proximal, symmetric muscle weakness, elevated serum creatine kinase, and mononuclear cell infiltrates in the muscle biopsy. Strong support for an autoimmune pathogenesis comes from histopathological findings in biopsies of affected muscles. Furthermore, the association with autoantibodies supports the notion that immune-mediated inflammation is involved. PM and DM may occur in isolation or in connection with a connective tissue disease or cancer. The current treatment for IIM consists of first-line high-dose steroids and various conventional second-line treatments. Improvements in treatment for IIM are hampered by difficulties in the design of trials and the low incidence and prevalence of the disease. Cytokines and chemokines are factors involved in the inflammatory process in IIM, and are candidates for future therapeutic targets. Preliminary data with anti-tumour necrosis factor therapy are not very promising, but results of blockers of the lymphotoxin signalling pathway are to be awaited. Anti-B cell therapy may be a valuable therapeutic option for treatment of refractory IIM. The effects of anti-interferon-alpha in IIM are to be awaited, as are results of other anti-cytokine therapies and anti-chemokine therapy. Outcome measures to be used in clinical trials in II M include at present the core sets of outcome proposed by the International Myositis Assessment Clinical Study Group (IMACS).     

The prevalence and clinical significance of anti-PUF60 antibodies in patients with idiopathic inflammatory myopathy

Autoantibodies against poly-U-binding factor 60 kDa protein (PUF60) have been reported in Caucasian dermatomyositis (DM) patients. However, their clinical significance in idiopathic inflammatory myopathy (IIM) remains to be fully clarified. Our objective was to analyze the prevalence and clinical significance of anti-PUF60 antibodies in a large cohort of Chinese IIM patients. In our study, 388 IIM patients, 301 disease controls, and 167 healthy controls (HCs) were involved. An enzyme-linked immunosorbent assay (ELISA) was developed to detect serum anti-PUF60 levels and was validated using immunoblotting methods. Unpaired Mann-Whitney U test and Spearman correlation analysis were used when appropriate. Anti-PUF60 antibodies were observed in IIM patients at a frequency of 10.6% (41/388). Subgrouping analysis revealed that the prevalence of anti-PUF60 antibodies was 10% in DM, 5.5% in polymyositis (PM), 10% in immune-mediated necrotizing myositis (IMNM), and 26.5% in myositis-overlap syndrome. Anti-PUF60 antibodies were also observed in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren’s syndrome (SS) patients at a positive rate of 17.3, 14.5, and 10.1% respectively. Intriguingly, anti-PUF60 antibodies were frequently observed in clinically amyopathic dermatomyositis (CADM) patients and DM patients without currently known myositis autoantibodies. Furthermore, DM patients with anti-PUF60 antibodies had higher prevalence of skin ulcerations. Moreover, longitudinal investigation in eight DM patients with anti-PUF60 antibodies revealed that the antibodies levels decreased with disease remission. Anti-PUF60 antibodies were nonspecific for myositis, since they could be detected in other rheumatic diseases. Further investigation of anti-PUF60 antibodies may reveal shared pathogenic pathways in systemic autoimmune disorders.     

Update on the genetics of the idiopathic inflammatory myopathies

A number of lines of investigation suggest that, as is likely the case for other autoimmune diseases, the idiopathic inflammatory myopathies (IIM) develop as a result of specific environmental exposures in genetically susceptible individuals. Current data imply that multiple genes are involved in the etiology of these complex disorders. Targeted gene studies and whole genome approaches have begun to identify several genetic risk factors for autoimmune diseases, but the rarity and heterogeneity of the IIM have limited our knowledge of their associated genes. Current findings suggest that human leukocyte antigen (HLA) genes on chromosome 6, particularly HLA DRB1*0301 and the linked allele DQA1*0501, have the strongest associations with all clinical forms of IIM in white patients. Different HLA alleles, however, may confer risk or protection for myositis in distinct ethnic, serologic, and environmental exposure groups. Non-HLA genetic risk factors, which have been documented for other autoimmune diseases, are now being identified for the IIM. These include polymorphic genes encoding immunoglobulin heavy chains (defined by serologic markers known as Gm allotypes), cytokines and their receptors, and certain proteins that accumulate in the myocyte vacuoles of inclusion body myositis patients. Selected allelic polymorphisms of interleukin-1 receptor antagonist variable number tandem repeats and genes for tumor necrosis factor alpha and interleukin-1 alpha also have recently been associated with IIM. The pathogenic bases for the differences among the many clinically, pathologically and immunologically defined syndromes known as the IIM will be elucidated through a better understanding of the multiple genes that define risks for their development, as well as through investigations of gene-gene and gene-environment interactions.     

Genetic and environmental risk factors for idiopathic inflammatory myopathies

Although the studies discussed are beginning to reveal a number of genetic and possible environmental risk factors for myositis, further investigations are needed to fully understand and classify these syndromes. The difficulties in this process include small numbers of subjects with varying disease phenotypes available for study, polygenic risk factors for which it remains unclear which are primary and which are secondary or linked genes, and the lack of validated environmental exposure assessment tools. New technologies and international collaborative approaches, however, may overcome some of these difficulties and allow us to identify genetic and environmental risk factors, as well as the critical gene-environment interactions in the IIM and its subgroups. Nonetheless, our understanding of these diseases is still in the early stages. Although we have learned a great deal about these disorders through detailed investigations over the last several decades, we have even further to go to understand the environmental triggers and genetic susceptibilities for the myositis syndromes.     

Platelet-endothelial cell adhesion molecule-1 and CD146: soluble levels and in situ expression of cellular adhesion molecules implicated in the cohesion of endothelial cells in idiopathic inflammatory myopathies

OBJECTIVE: Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of diseases characterized by chronic inflammation of muscles. We investigated the role of cellular adhesion molecules implicated in the cohesion of endothelial cells in IIM. METHODS: In 22 patients with IIM we investigated plasma concentrations of soluble junctional adhesion molecules [platelet-endothelial cell adhesion molecule (sPECAM-1) and sCD146] and cellular adhesion molecules [sP-selectin, sE-selectin, intercellular adhesion molecule (sICAM-1), and vascular cell adhesion molecule (sVCAM-1)] implicated in leukocyte/endothelial cell interactions. Results were compared to a control group. Muscle biopsy samples from 8 out of 22 IIM patients were studied by immunohistochemistry for tissue expression of these molecules and compared to normal muscle samples. PECAM-1 and CD146 expression was also studied using immunoblots from muscle biopsies from 5 patients and 2 controls. RESULTS: We observed distinct patterns of soluble levels and in situ expression between dermatomyositis (DM), polymyositis (PM), and sporadic inclusion body myositis (s-IBM). PM samples showed significantly increased levels of sCD146, sPECAM-1, and s-ICAM1 and increased expression of CD146, CD31, and ICAM-1 in endothelial cells, whereas CD146 and ICAM-1 were also recorded in some muscle fibers. In DM, sE-selectin, sP-selectin, and sPECAM-1 were significantly increased, with abnormal expression of ICAM-1 in endothelial cells and perifascicular muscle fibers. In the small group of s-IBM samples, results were similar to PM, but the only significant increase was the level of sPECAM-1. Immunoblots confirmed increased expression of PECAM-1 and CD146 in all IIM muscles in comparison to controls, with the highest expression in PM and IBM samples. CONCLUSION: We observed abnormal increases of soluble levels of adhesion molecules implicated in endothelial cell junctions in PM (sCD146, sPECAM-1) and to a lesser extent in DM and s-IBM (sPECAM-1). We conclude that the distinctly different profiles between PM/s-IBM and DM reflect differences in the pathophysiological background of these diseases.     

Characterization of relapses in adult idiopathic inflammatory myopathies

The objective of the current report was to determine the relapse rates and characterize the nature of relapses during the disease course of adult patients with idiopathic inflammatory myopathies (IIM). A retrospective cohort study of 53 medical records of patients with polymyositis (PM), dermatomyositis (DM), connective tissue disease (CTD)-associated myositis, and malignancy-associated myositis at an academic rheumatology center was performed. Medical records were reviewed to determine clinical presentation, initial treatment, and clinical follow-up, with an emphasis on relapses. Relapses were defined as a sustained elevation in serum creatine kinase (CK) levels in the absence of an alternative etiology. Patients were followed for an average of 65±43 months. All patients received corticosteroids, and 35 patients received additional immunosuppressive medications as part of their initial treatment. Serum CK levels normalized in 51 patients, and muscle strength normalized in 43 patients. Biochemical relapse was observed in 33 patients (65%). Patients with PM and CTD-associated myositis had a higher relapse rate compared to DM and malignancy-associated myositis patients. Multiple relapses were observed in 17 patients. Relapses tended to occur within the first 2 years after treatment initiation and during the tapering phase of treatment. No risk factors were unequivocally identified, although advanced age and increased duration of symptoms prior to treatment initiation had nonsignificant associations with increased risk of relapse. In conclusion, initial treatment of IIM results in a high rate of normalization of serum CK and muscle weakness. However, physicians should be aware of the high rate of relapse in patients with IIM.     

Exercise in myositis: What is important,the prescription or the person?

Our aim for this narrative review was to undertake a search of studies into exercise for people living with Idiopathic Inflammatory myopathies (IIM). We explored the strength of existing evidence with a particular consideration for the implications for people living with IIM and what is important to them. The search strategy from the 2021 Cochrane Physical Activity review in neuromuscular disease was used, and we selected articles that included people with IIM, including Dermatomyositis (DM), Inclusion Body Myositis (IBM), Immune Mediated Necrotising Myopathy (IMNM) [also known as necrotizing autoimmune myopathy (NAM)], and Polymyositis (PM). 2967 records were screened and 16 were included in this review. Safety of exercise was demonstrated in nine articles, using a range of measures of disease activity, serum creatine kinase, indicators of inflammation, pain, or fatigue. Two studies that took muscle biopsies showed no evidence of increased inflammation. Aerobic exercise protocols were used in 8 studies across conditions and demonstrated improvements in cardiorespiratory fitness or exercise capacity. Six studies of strength training observed improvements in muscle function, with two studies reporting muscle biopsy results of amplified immune response and up regulation of genes related to recycling of damaged proteins. Nine of 13 studies that measures functional outcomes showed significant improvements, and evidence for behaviour change was observed in a study of a self-management intervention. The evidence of safety and effect of training is reassuring and welcome, and we now need to explore how we support people to incorporate exercise and physical activity longer term into active lifestyles.     

Genetic aspects in sarcoidosis.

Sarcoidosis is an immune-mediated, multiorgan, granulomatous disorder thought to be triggered by an intricate combination of environmental and genetic factors. Two robust lines of evidence support the hypothesis of a genetic component in the pathogenesis of sarcoidosis: racial variation in its epidemiology and familial clustering of cases. The relationship between epidemiology and environmental factors affecting variations in sarcoidosis incidence/prevalence and presentation are reviewed, as well as strategies to be pursued in the search for susceptibility genes for the disorder. Pathogenic processes leading to sarcoid granuloma formation and maintenance have prompted investigators interested in the genetics of sarcoidosis to focus mainly on major histocompatibility complex genes, and indeed a remarkable amount of data has been accumulated during the last two decades. Whilst in contrast with some autoimmune disorders a clear association between human leukocyte antigen (HLA) and sarcoidosis is still a controversial issue, there is, however, a general agreement that some HLA genes are related to phenotypic variations of the disease. Some genetic investigators have focused on T-cell receptor genes, immunoglobulin genes, angiotensin converting enzyme gene, chemokine genes and others. From a review of studies performed in different racial and ethnic groups, a reasonable suggestion arises that genetic factors are the major determinant in the racial variations in the epidemiology of the disorder. This assumption is, however, so far limited by lack of studies considering both genetic and environmental factors simultaneously.