Idiopathic inflammatory myositis

Macrophage involvement in idiopathic inflammatory myopathy: pathogenic mechanisms and therapeutic prospects

Idiopathic inflammatory myopathies are a group of systemic autoimmune diseases characterized by chronic muscle inflammation and diverse clinical manifestations. Macrophages, pivotal components of innate immunity, are implicated in immune responses, inflammation resolution, and tissue repair. Distinct macrophage polarization states play vital roles in disease progression and resolution. Mechanistically, activated macrophages release proinflammatory cytokines, chemokines, and reactive oxygen species, perpetuating immune responses and tissue damage. Dysregulated macrophage polarization contributes to sustained inflammation. Here, we reviewed the intricate contributions of macrophages to IIM pathogenesis and explored novel therapeutic avenues. We discussed emerging strategies targeting macrophages, including receptor-based interventions and macrophage polarization modulation, for IIM treatment. This review underscores the multifaceted involvement of macrophages in IIM pathogenesis and offers insights into potential therapeutic approaches targeting these immune cells for disease management.

Cancer Risk and Mortality in Hospitalized Patients With Idiopathic Inflammatory Myopathies in Western Australia

OBJECTIVE

To compare cancer incidence, type, and survival between patients with idiopathic inflammatory myopathies (IIMs) in Western Australia (WA) and the general population.

METHODS

Administrative health data for hospitalized patients with incident IIM (n = 803, 56.5% female, median age 62.0 yrs), classified by a validated algorithm as polymyositis (PM; 36.2%), dermatomyositis (DM; 27.4%), inclusion body myositis (IBM; 17.1%), overlap myositis (OM; 10.7%), and other IIM (8.6%), were linked to WA cancer and death registries for the period of 1980 to 2014. Cancer incidence rates (CIRs) before and after IIM diagnosis as well as cancer mortality were compared with age-, sex-, and calendar year-matched controls (n = 3225, 54.9% female, median age 64 yrs) by rate ratios (RRs) and Kaplan-Meier survival estimates.

RESULTS

The prediagnosis CIR was similar for patients with IIM and controls (6.57 vs 5.95; RR 1.11, 95% CI 0.88-1.39) and for patients evolving to DM (n = 220) or other IIM subtypes (6.59 vs 6.56; RR 1.01, 95% CI 0.38-3.69). During follow-up, CIR was higher for all DM (4.05, 95% CI 3.04-5.29), with increased CIR for lung cancer vs controls (1.05 vs 0.33; RR 3.18, 95% CI 1.71-5.47). Cancer post diagnosis shortened life span by 59 months for patients with IIM (103 vs 162 months, P < 0.01), but reduced survival rates were observed only in patients with DM and IBM.

CONCLUSION

Cancer risk was not increased prior to IIM, but CIR for lung cancer was increased following DM diagnosis. As cancer reduced survival only in patients with DM and IBM, these data support a strategy of limited cancer screening in IIM.

The spectrum of idiopathic inflammatory myopathies in Western Australia: epidemiological characteristics and mortality over time

To determine long term overall and subgroup specific incidence rates and associated mortality for idiopathic inflammatory myopathies (IIM) in a population wide study. We included patients hospitalised between 1980 and 2015 with incident IIM as defined by relevant diagnostic codes for dermatomyositis (DM) polymyositis (PM), inclusion body myositis (IBM), other IIM and overlap myositis (OM) in the Western Australia Health Hospital Morbidity Data Collection (n = 846). Trends over time for annual incidence rate per million population (AIR) were analysed by least square regression and Kaplan-Meier survival and mortality rates (MR)/100 person years compared with a matched control group (n = 3681). The averaged AIR for all IIM was 19 (CI 10.4-27.5) and stable over time with point prevalence reaching 205.3 (CI 185.6-226.6) per million in 2015. Over time, the AIR for DM 5.0 (CI 0.6-9.4) and IBM 3.3 (CI 0.7-9.6) was stable, while AIR decreased for PM (p < 0.01) and increased for other IIM (p < 0.01) and OM (p < 0.01). IBM patients were eldest at diagnosis (68 years, CI 59-77) with male preponderance in IBM (53.4%) and other IIM (55.8%) groups. Crude mortality (54.5 vs 41.3%), MR ratio (6.65 vs 5.91) and 5 (65.8% vs 71.6%) and 10-year (52.5% vs 58.7%) survival were all worse for IIM patients (all p < 0.05). IBM patients had highest MR (10.1; CI 8.38-12.14) and lowest 10-year survival (39.2%). While cardiovascular disease and cancer were predominant causes of death, they were proportionally lower in IIM patients, where respiratory and rheumatic disease were more frequent causes of death. While the overall incidence of IIM in WA was stable over 35 years, the spectrum of IIM has changed significantly with increases especially in other IIM and OM. The overall prognosis with IIM remains guarded with 10-year survival just over 50%.

Epidemiology of the idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic autoimmune diseases that affect the skeletal muscles and can also involve the skin, joints, lungs and heart. The epidemiology of IIM is obscured by changing classification criteria and the inherent shortcomings of case identification using healthcare record diagnostic coding. The incidence of IIM is estimated to range from 0.2 to 2 per 100,000 person-years, with prevalence from 2 to 25 per 100,000 people. Although the effects of age and gender on incidence are known, there is only sparse understanding of ethnic differences, particularly in indigenous populations. The incidence of IIM has reportedly increased in the twenty-first century, but whether this is a genuine increase is not yet known. Understanding of the genetic risk factors for different IIM subtypes has advanced considerably. Infections, medications, malignancy and geography are also commonly identified risk factors. Potentially, the COVID-19 pandemic has altered IIM incidence, although evidence of this occurrence is limited to case reports and small case series. Consideration of the current understanding of the epidemiology of IIM can highlight important areas of interest for future research into these rare diseases.

Inflammatory myopathies and beyond: The dual role of neutrophils in muscle damage and regeneration

Skeletal muscle is one of the most abundant tissues of the human body and is responsible for the generation of movement. Muscle injuries can lead to severe disability. Skeletal muscle is characterized by an important regeneration capacity, which is possible due to the interaction between the myoblasts and immune cells. Neutrophils are fundamental as inducers of muscle damage and as promoters of the initial inflammatory response which eventually allows the muscle repair. The main functions of the neutrophils are phagocytosis, respiratory burst, degranulation, and the production of neutrophil extracellular traps (NETs). An overactivation of neutrophils after muscle injuries may lead to an expansion of the initial damage and can hamper the successful muscle repair. The importance of neutrophils as inducers of muscle damage extends beyond acute muscle injury and recently, neutrophils have become more relevant as part of the immunopathogenesis of chronic muscle diseases like idiopathic inflammatory myopathies (IIM). This heterogeneous group of systemic autoimmune diseases is characterized by the presence of muscle inflammation with a variable amount of extramuscular features. In IIM, neutrophils have been found to have a role as biomarkers of disease activity, and their expansion in peripheral blood is related to certain clinical features like interstitial lung disease (ILD) and cancer. On the other hand, low density granulocytes (LDG) are a distinctive subtype of neutrophils characterized by an enhanced production of NETs. These cells along with the NETs have also been related to disease activity and certain clinical features like ILD, vasculopathy, calcinosis, dermatosis, and cutaneous ulcers. The role of NETs in the immunopathogenesis of IIM is supported by an enhanced production and deficient degradation of NETs that have been observed in patients with dermatomyositis and anti-synthetase syndrome. Finally, new interest has arisen in the study of other phenotypes of LDG with a phenotype corresponding to myeloid-derived suppressor cells, which were also found to be expanded in patients with IIM and were related to disease activity. In this review, we discuss the role of neutrophils as both orchestrators of muscle repair and inducers of muscle damage, focusing on the immunopathogenesis of IIM.

Glomerulopathy in patients with dermatomyositis in early active disease: clinical, pathological and capillaroscopic manifestations, and response to treatment

Introduction

Idiopathic inflammatory myopathies (IIMs) are a group of systemic connective tissue diseases that present with muscular and extra-muscular manifestations. There are few reports on kidney involvement, especially in dermatomyositis (DM) patients. We evaluated the clinical, laboratory, capillaroscopy, and kidney pathology of patients with DM, who presented with proteinuria during the first year, and followed them for response to treatment.

Material and methods

We evaluated 205 patients with proximal muscle weakness or high muscle enzymes, who referred to the nailfold capillaroscopy clinic from April 2010 to October 2021. Seventy-four patients fulfilled the New 2017 EULAR/ACR Classification Criteria for adult and juvenile IM with probability of ≥ 90% for DM with duration of ≤ 12 months and proteinuria > 350 mg/24 hours. All manifestations of patients with glomerulopathy and their kidney biopsies were reviewed, and they were followed for their treatment response.

Results

From 74 patients with DM, 52 female and 22 male, median age 37 (19–65) years, and disease duration of median 4.5 (1–12) months, 2 (2.7%) patients (25- and 28-year-old male) had proteinuria. Their kidney biopsy showed mesangioproliferative glomerulonephritis (GN). There was no case of acute or chronic kidney damage or rhabdomyolysis. Both had high disease activity, high erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), abnormal capillaroscopy, and high anti-Ro positivity with good early response of their kidney function, muscle weakness, and laboratory tests after immunosuppressive treatment for 3–6 months. One patient had capillaroscopy follow-up, and all abnormalities were resolved in 8 fingers. One patient, due to poor follow-up, after 8 months had recurrence of his disease.

Conclusions

We found mesangioproliferative GN as a rare extra-muscular manifestation in patients with DM in the active and early phase of the disease. Full immunosuppressive treatment showed early complete recovery in these patients.

Association of Cytomegalovirus Infection With Anti-MDA5 Antibody-Positive Dermatomyositis: A Prospective Cohort Study

Objectives: To investigate whether cytomegalovirus (CMV) infection plays a role in the pathogenesis and prognosis of idiopathic inflammatory myopathy (IIM), particularly in anti-MDA5 antibody-positive (anti-MDA5⁺) dermatomyositis (DM).

Methods: A prospective cohort of 204 newly diagnosed IIM patients and 50 healthy individuals were enrolled in the study. CMV-IgM and CMV-IgG antibody concentrations and lymphocyte counts were analyzed. Differences in categorical data were compared using Fisher's exact test and the chi-square test. One-year survival rates were analyzed in MDA5⁺ DM patients with and without CMV infection.

Results: In IIM patients, the median CMV-IgM level was significantly higher than in healthy controls (6 U/mL vs. 0 U/mL, p < 0.05) as was the median CMV-IgG level (114 U/mL vs. 105 U/mL, p < 0.05). The percentage of recent CMV infections in the MDA5⁺ DM group was much higher than it was in the MDA5⁻ IIM group (19.1% vs. 7.0%, p = 0.009). MDA5⁺ DM patients with CMV DNA-emia had poorer 1 year survival than the CMV-DNA⁻ group (33.3% vs. 86.3%, p = 0.010). CMV-IgM-positive (CMV-IgM⁺) MDA5⁺ DM patients had lower CD4⁺ T cell counts (245.7 cells/μL vs. 420.5 cells/μL, p < 0.05) and CD19⁺ B cell counts (97.3 cells/μL vs. 240.6 cells/μL, p < 0.05).

Conclusion: The number of CMV infections was significantly higher in IIM patients, particularly in MDA5⁺ DM patients. Lower CD4⁺ T cells and CD19⁺ B cells were observed in CMV-IgM⁺ MDA5⁺ DM patients. CMV infection may have an important role in the pathogenesis and prognosis of MDA5⁺ DM by disrupting immunity.

Myositis autoantibodies in Iranian myositis patients: assessment the frequency and clinical relevancy

INTRODUCTION

Dermatomyositis (DM) and polymyositis (PM) are known as two major types of idiopathic inflammatory myopathies (IMMs). During the past years, growing data strongly suggest the clinical significance of myositis-associated autoantibodies (MAAs) and myositis-specific autoantibodies (MSAs). The present study aimed to determine the profile of MSAs and MAAs, subsequently to address the clinical significance of these autoantibodies in Iranian myositis patients.

METHODOLOGY

In this cross-sectional study, 28 DM and 24 PM patients were entered. Demographic and clinical characteristics were collected by direct examination and patients' medical record. The existence of MSAs and MAAs was assessed by indirect immunofluorescence then using immunoblotting (FA 1510-1005-1, DL 1530-1601-4 G; Euroimmun, Germany). Data were analyzed using the SPSS software (v22; SPSS Inc. Chicago, IL, USA).

RESULTS

The mean age of the patients was 46.18 ± 12.95 years and male/female ratio was 28.8/71.2. Autoantibodies were positive in 63.46% of myositis patients. Interestingly, anti-TIF1γ and anti-PL7 were significantly associated with malignancy (P < 0.001, P = 0.008; respectively). The existence of autoantibody and anti-Jo1 had significant relation with interstitial lung disease (ILD) (P = 0.034, P = 0.006; respectively). Joint involvements including arthritis and arthralgia were significantly associated with anti-Ro52 and anti-Jo1 (P = 0.04, P = 0.02; respectively).

CONCLUSION

Taken together, it can be concluded that certain myositis autoantibodies present clinical significance which is in line with the literature. The use of these autoantibodies as biomarkers by line blotting along with indirect immunofluorescence facilitates diagnosis of inflammatory myopathies and makes it more accurate as well as better management of myositis patients if used based on a science-based manner. Key Points • Identification of MSAs and MAAs facilitates the diagnosis of inflammatory myopathies and provides better myositis patient's management if used according to a science-based manner. • Anti-rod and ring antibody was detected in a patient with ovarian cancer-induced dermatomyositis. • Malignancy and ILD are integrated parts of myositis which can be associated with MSAs and MAAs.

The Utility of Shear-Wave Elastography in the Evaluation of Myositis

Changes in muscle elasticity are expected in patients with untreated myositis. The purpose of this study was to define the accuracy of shear-wave elastography (SWE) in diagnosing myositis. This case control study included 21 patients (mean age, 49.4 y; 12 women) with myositis who underwent SWE, magnetic resonance imaging (MRI) and biopsy of the involved muscle group. SWE was performed accordingly in a control group (n = 24; mean age, 51.2 y; 8 women). Blood tests consisted of creatine kinase (CK) and aldolase. Two operators performed SWE in longitudinal and transverse planes of muscular fibers, quantifying the mean shear-wave velocity (SWV) and the pattern of stiffness. On MRI, short-TI inversion recovery (STIR) signal hyperintensity and T1 contrast enhancement of muscle was considered diagnostic for myositis. The patient group suffered from different types of myositis (nine patients with polymyositis, eight with dermatomyositis and four with other types of myositis). Blood tests showed significantly increased CK and aldolase values in patients with myositis (p < 0.001 and p < 0.0001). MRI showed a sensitivity of 0.95. In the patient group, the mean SWVs of longitudinal and transverse measurements were 2.8 ± 1.4 m/s and 3.1 ± 1.2 m/s, respectively. In the control group, SWVs were 2.3 ± 0.5 m/s and 2.4 ± 0.5 m/s, respectively. The difference between transverse measurements was significant (p = 0.02). Increased heterogeneity as a marker for myositis in transverse SWE showed a sensitivity of 0.8, specificity of 0.79, positive predictive value (PPV) of 0.76 and negative predictive value (NPV) of 0.82. Inter-observer difference was very low (κ = 0.92). Increased heterogeneity in both planes compared with histologic results showed a sensitivity of 0.56, specificity of 0.93, PPV of 0.91 and NPV of 0.62. Spearman correlation between CK <1000 U/L and SWE was 0.54. In conclusion, transverse orientation SWE may serve as an imaging biomarker for the diagnosis of myositis through the display of a heterogeneous pattern and increased absolute SWV values of inflamed muscles.

Time-Dependent Analysis of Risk of New-Onset Heart Failure Among Patients With Polymyositis and Dermatomyositis

OBJECTIVE

To determine the risk and time trends of heart failure (HF) leading to hospitalization in individuals newly diagnosed as having polymyositis/dermatomyositis (PM/DM) relative to non-PM/DM controls at the general population level.

METHODS

A retrospective cohort study was conducted using data from a nationwide insurance database in Taiwan. Patients with incident PM/DM and without a history of HF were selected between 2000 and 2013. Unmatched and propensity score-matched cohorts were established separately. A multivariable Cox proportional hazards regression model was used to estimate the adjusted hazard ratio (HR) for the risk of HF in the unmatched cohort. In the propensity score-matched cohort, general population controls were selected and matched at a 1:1 ratio to the patients with PM/DM based on propensity scores, which accounted for the confounding factors of age, sex, index date (year) of first diagnosis, comorbidities, and medication usage. The cumulative incidence of HF was estimated using the Kaplan-Meier method. A stratified Cox proportional hazards model was used to calculate the HR for the risk of HF events at different follow-up time points among patients with PM/DM compared with non-PM/DM controls in the propensity score-matched cohort.

RESULTS

In the unmatched cohort, the study assessed 2,025 patients with PM/DM and 196,109 general population controls. Results of multivariable Cox regression analysis, adjusted for age, sex, comorbidities, and medication usage, revealed a greater risk of HF leading to hospitalization in the PM/DM group than in the control group (adjusted HR 3.29, 95% confidence interval [95% CI] 2.60-4.18). After matching based on propensity score, a total of 1,997 pairs of PM/DM patients and general population controls were identified. In this propensity score-matched cohort, the cumulative incidence of HF in patients with PM/DM at 3 years, 5 years, and 10 years was 3.3%, 4.4%, and 7.4%, respectively. The absolute difference in HF risk in the PM/DM group compared with the control group was 1.8% at 3 years, 2.1% at 5 years, and 3.0% at 10 years. Compared with general population controls, patients with PM/DM exhibited an augmented risk of HF (HR 2.06, 95% CI 1.36-3.12). Analyses stratified according to follow-up time point revealed that the increased risk of HF persisted for up to 10 years after the PM/DM diagnosis.

CONCLUSION

These results indicate that the risk of HF leading to hospitalization was increased in patients with PM/DM throughout the study period, supporting the need for greater vigilance in the monitoring of patients with PM/DM for the development of this potentially lethal complication.

Myositis specific antibodies are associated with isolated anti-Ro-52 associated interstitial lung disease

OBJECTIVES

Anti-Ro-52 antibody positivity might be associated with the presence of interstitial lung disease (ILD) among patients with autoimmune features. However, the clinical significance of isolated anti-Ro-52 positivity (i.e., the presence of anti-Ro52 antibodies but the absence of anti-Ro60 antibodies; anti-Ro52+-Ro60-) in patients with ILD is not clear.

METHODS

This is a prospective and observational study of Chinese ILD patients with isolated anti-Ro-52 positivity. According to their myositis-specific antibody (MSA) status, patients were split into groups, and their clinical and radiological features were compared.

RESULTS

Of the 158 enrolled patients with ILD and isolated anti-Ro-52 positivity (isolated anti-Ro-52-ILD), there were 130 patients with a positive MSA status and 28 patients with a negative MSA status. Anti-synthetase antibodies (ASAs) were found in 61.5% of patients with MSA+ ILD, and anti-melanoma differentiated-associated protein 5 (MDA-5) antibodies were found in the remaining 38.5% of patients. The anti-nuclear antibody (ANA) pattern was associated with ASA and anti-MDA-5 positivity (χ2=70.7, P < 0.001; Cramer's value 0.47, P < 0.001): ANA negativity was associated with anti-MDA-5 positivity, and cytoplasmic ANA positivity was associated with ASA positivity. There were statistically significant differences in the high-resolution CT patterns between patients with isolated anti-Ro-52 positivity with different MSA statuses (χ2=29.8, P < 0.001; Cramer's value 0.31, P < 0.001): OP pattern was more common in patients with anti-MDA-5 antibodies than in those without anti-MDA-5 antibodies.

CONCLUSIONS

Patients with isolated anti-Ro-52-ILD showed high positivity of MSA. Isolated anti-Ro-52 positivity with cytoplasmic ANA positivity was strongly associated with ASA+-ILD, while ANA negativity was associated with anti-MDA-5+-ILD.

Muscle pathological features and extra-muscle involvement in idiopathic inflammatory myopathies with anti-mitochondrial antibody

OBJECTIVE

Anti-mitochondrial antibodies (AMAs) can be detected in some idiopathic inflammatory myopathy (IIM) patients. We aimed to investigate the clinical features of IIM patients with AMAs.

METHODS

We retrospectively analysed 1,167 consecutive patients with IIM for AMA-associated myositis and compared them to age- and gender-matched AMA-negative IIM patients.

RESULTS

Twenty-nine patients (2.5%) were identified with AMA-positive myositis; eight of them had primary biliary cholangitis (PBC). There were no significant differences in skin rash, dysphagia, interstitial lung disease, and muscle strength between AMA-positive patients and AMA-negative patients. Of 23 cases, 12 (52.2%) showed immune-mediated necrotizing myopathy (IMNM)-like pathological features. amongst AMA-positive patients, 11 of 16 patients with isolated anti-AMAs were classified as IMNM which was significantly higher than that of patients with coexistent anti-AMAs and myositis-specific antibodies (p = 0.026). Moreover, subclinical cardiac involvement was significantly more common in AMA-positive patients than in AMA-negative patients (21/29 VS 33/116, p<0.001). In addition, patients without PBC had a significantly higher incidence of abnormal echocardiography findings than that of patients with PBC (p = 0.009). Patients without heart abnormalities took significantly less time to achieve disease remission and prednisone tapering to <10 mg than patients with heart abnormalities (p = 0.000 and p = 0.001, respectively).

CONCLUSIONS

IMNM was a major histopathological finding in IIM patients with isolated AMAs. AMAs were significantly associated with subclinical cardiac involvement in IIM. PBC seemed to be a protective factor for abnormal echocardiography findings in AMA-positive patients. Patients without heart involvement took less time to achieve disease remission and prednisone tapering off.

Clinical characteristics of interstitial lung diseases positive to different anti-synthetase antibodies

To analyze the clinical, serological, and imaging characteristics of patients with interstitial lung diseases (ILD) positive to different anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies.The clinical data, serological indexes, pulmonary high-resolution computed tomography (HRCT) imaging features and pulmonary functions, and bronchoalveolar lavage fluid of 84 ILD patients with anti-ARS antibody positive in Beijing Chao-yang Hospital, Capital Medical University were reviewed.(1) Anti-ARS antibodies included anti-Jo-1 (42.86%), anti-PL-7 (26.19%), anti-PL-12 (10.71%), anti-EJ (14.29%), and anti-OJ (5.95%). (2) Nonspecific interstitial pneumonia was the main type of patients with ILD positive to antibodies of anti-Jo-1, anti-PL-7, and anti-EJ, organizing pneumonia was the main type of patients with ILD positive to anti-PL-12 antibody and usual interstitial pneumonia was the main type of patients with ILD positive to anti-OJ antibody. (3) Only 14.29% of the patients had typical "triad syndrome" (interstitial pneumonia, myositis, and non-erosive arthritis). Myositis mainly occurred in patients with ILD positive to antibodies of anti-PL-7, anti-Jo-1, and anti-EJ. The incidence of arthritis in ILD patients with anti-Jo-1 was higher than that in ILD patients with anti-PL-12 and anti-EJ (P < .05). The incidence of mechanic's hand in ILD patients with anti-Jo-1 was higher than that in ILD patients with anti-PL-12 (P < .05).ILD positive to anti-Jo-1 antibody is associated with multiple organ involvement, mainly manifested as myositis, mechanic's hand, and arthritis. As other clinical manifestations of some ILD patients are relatively hidden, ILD patients should pay attention to the screening of the anti-ARS antibodies and guard against anti-synthetase syndrome.

Geographical Latitude Remains as an Important Factor for the Prevalence of Some Myositis Autoantibodies: A Systematic Review

The idiopathic inflammatory myopathies (IIM) are characterized by muscular weakness, cutaneous manifestations, muscle damage revealed by increase of muscular enzymes, muscle biopsy, electromyography and changes on magnetic resonance imaging. However, the hallmark of these IIM, is the development of myositis specific antibodies (MSA) or myositis associated antibodies (MAA). The theories about their presence in the serum of IIM is not known. Some studies have suggested that some of these MSA, such as anti-Mi-2 increases according to the intensity of UV radiation. There is scarce information about the environmental factors that might contribute in order to be considered as triggering factors as UV radiation might be. In this review, we analyzed the reported prevalence of MSAs and MAAs regarding to their geographical location and the possible relation with UV radiation. We collected the prevalence data of fifteen MSA and thirteen MAA from 22 countries around the world and we were able to observe a difference in prevalence between countries and continents. We found differences in anti-PL7, anti-Ro52, anti-La and anti-Ku prevalence according to UV radiation level. Otherwise, we observed that anti-Mi-2 prevalence increases near to the Equator meanwhile anti-MJ/NXP2 and anti-ARS prevalence had an opposite behavior increasing their prevalence in the geographical locations farther to the Equator. Our results highlighted the importance to include the UV radiation and other environmental factors in IIM studies, in order to clarify its association with MSA and MAA prevalence as well as its possible role in the immunopathogenesis of these diseases.

Health-related quality of life and work impairment in idiopathic inflammatory myopathies in South Australia

AIM

The idiopathic inflammatory myopathies (IIM) are rare autoimmune diseases that are usually chronic and often present with skeletal muscle inflammation and weakness. We sought to examine the impact of IIM in a cohort of 50 South Australian patients on health-related quality of life (HRQOL) and work productivity (WP). We uniquely categorized patients across gender, IIM subtypes, employment status, and also whether there was extramuscular involvement from IIM.

METHODS

Multiple modalities were used, as recommended by the International Myositis Assessment and Clinical Studies Group (IMACS), to assess the impact of IIM, including manual muscle strength testing (MMT-8), the Physician and Patient Global Activity Assessments (PHGAA, PTGAA), Myositis Disease Activity Assessment Tool (MDAAT), and serum creatinine kinase (CK) levels. The impacts of IIM on HRQOL and WP were analyzed using the Medical Outcomes Study 36-items Short Form (SF-36) and Work Productivity and Activity Impairment (WPAI) questionnaires, respectively.

RESULTS

We found significantly lower HRQOL outcome scores in most of the SF-36 domains when compared to the most recent population norms (P ≤ .01). Physical health was predominantly affected with relative preservation of emotional health. There were also significant associations between MMT-8, PHGAA and PTGAA scores and HRQOL and WP.

CONCLUSIONS

Our findings highlight the significant impact of IIM on HRQOL and WP in a well-characterized cohort of patients with IIM within Australia, and therefore the importance of a holistic approach to the management of these patients.

Seasonal and residential clustering at disease onset of anti-MDA5-associated interstitial lung disease

OBJECTIVES

To investigate whether the onset of polymyositis (PM)/dermatomyositis (DM)-associated interstitial lung disease (ILD) is influenced by season and residence in the context of myositis-specific autoantibodies.

METHODS

For patients with PM/DM-associated ILD enrolled in a multicentre cohort, 365 and 481 patients were eligible for seasonal and geographical analysis, respectively, based on the availability of reliable clinical information. The patients were divided into three groups: (1) anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive patients, (2) anti-aminoacyl tRNA synthetase (anti-ARS) antibody-positive patients and (3) patients negative for those antibodies. Seasonality was assessed by the Rayleigh test. Distance from residence to the nearest waterfront was measured on Google Map and was compared between groups by the exact Wilcoxon rank-sum test.

RESULTS

In anti-MDA5-positive patients, the disease developed more frequently in October-March (p=0.03), whereas a seasonal relationship was not found in the remaining two patient groups. Residence at disease onset in anti-MDA5-positive patients was significantly closer to the waterfront, especially to freshwater, compared with that in anti-ARS-positive or anti-MDA5-/ARS-negative patients (p=0.003 and 0.006, respectively).

CONCLUSIONS

Anti-MDA5-associated ILD occurred predominantly from October to March in individuals residing near freshwater, suggesting an environmental influence on the onset of this disease subset.

Reclassification of Korean patients with polymyositis and dermatomyositis based on the Bohan and Peter criteria by the 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies

BACKGROUND/AIMS

We investigated the concordance rate of the classification of polymyositis (PM) and dermatomyositis (DM) between the Bohan and Peter criteria and the 2017 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for idiopathic inflammatory myopathies (IIMs) (the 2017 EULAR/ACR criteria) in Korean patients.

METHODS

We retrospectively reviewed the medical records of 137 patients with PM and DM. We finally included 72 PM patients and 49 DM patients who fulfilled the Bohan and Peter criteria for PM and DM and reclassified them by the 2017 EULAR/ ACR criteria.

RESULTS

Three patients (4.2%) with probable PM were newly reclassified as non-IIM due to a total score of 5.3 or smaller. Meanwhile, one patient with possible PM was newly reclassified as probable PM due to the presence of dysphagia. In addition, eight patients (16.3%) with possible DM with DM-specific typical skin rash were newly reclassified as amyopathic DM (ADM) due to the absence of proximal muscle weakness. The concordance rate of the classification between the Bohan and Peter criteria and the 2017 EULAR/ACR criteria was 95.8% for PM patients and 83.7% for DM patients.

CONCLUSION

The Bohan and Peter criteria were comparable to the 2017 EULAR/ ACR criteria for classifying PM and DM in Korean patients. Considering the convenience of the Bohan and Peter criteria in the real clinical settings, we suggest that the old criteria should be preferentially applied and then performing muscle biopsy should be considered in a patient suspected of PM without antihistidyl tRNA synthetase (anti-Jo-1). Moreover, we suggest that ADM could also clinically be classified by the old criteria.

AST/ALT ratio as a predictor of mortality and exacerbations of PM/DM-ILD in 1 year-a retrospective cohort study with 522 cases

OBJECTIVE

To assess the associations between aspartate transaminase/alanine transaminase ratio (DRR) and mortality in patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD).

PATIENTS AND METHODS

This was a retrospective cohort study, which included 522 patients with PM/DM-ILD whose DRR on admission were tested at West China Hospital of Sichuan University during the period from January 1, 2008, to December 31, 2018. Cox regression models were used to estimate hazard ratios for mortality in four predefined DRR strata (≤ 0.91, 0.91-1.26, 1.26-1.73, and > 1.73), after adjusting for age, sex, DRR stratum, diagnosis, overlap syndrome, hemoglobin, platelet count, white blood cell count, the percentage of neutrophils, neutrophil/lymphocyte ratio, albumin, creatine kinase, uric acid/creatinine ratio, triglycerides, or low-density lipoprotein.

RESULTS

Higher DRR (> 1.73) was an independent predictor of 1-year mortality in multivariate Cox regression analysis (hazard ratio 3.423, 95% CI 1.481-7.911, p = .004). Patients with higher DRR more often required the use of mechanical ventilation and readmission for acute exacerbation of PM/DM-ILD at 1-year follow-up.

CONCLUSION

Higher DRR on admission for PM/DM-ILD patients are associated with increased mortality, risk of mechanical ventilation, and hospitalization in 1-year follow-up. This low-cost, easy-to-obtain, rapidly measured biomarker may be useful in the identification of high-risk PM/DM-ILD patients that could benefit from intensive management.

Retrospective Analysis of Cancer-Associated Myositis Patients over the Past 3 Decades in a Hungarian Myositis Cohort

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.

Fibrous myopathy induced by intramuscular injections of cyclizine

A 63-year-old woman was referred to neurology with bilateral severe progressive pain and stiffness in her thighs. The patient had a 3-year history of injecting intramuscular cyclizine into the anterior thigh to treat nausea associated with a longstanding pan-enteric dysmotility syndrome. MRI of the thighs demonstrated fibrotic appearances. A biopsy of the left vastus lateralis and surrounding fascia identified pathology consistent with a fibrous myopathy. The patient was advised to stop intramuscular injections of cyclizine and undergo physiotherapy but she still remained in considerable pain. Although fibrous myopathy occurring as a consequence of recurrent intramuscular drug injections, particularly heroin, has been previously described, this is the first report of fibrous myopathy associated with the use of intramuscular cyclizine. We highlight this rare association and suggest that the long-term use of intramuscular cyclizine be avoided.

Inpatient burden and resource utilization of polymyositis and dermatomyositis: A 10-year Study of National Inpatient Sample

OBJECTIVES

To characterize inpatient prevalence and resource utilization of patients with polymyositis (PM) and dermatomyositis (DM).

METHODS

Patients with PM/DM were identified from the Nationwide Inpatient Sample (NIS) database from the year 2005 to 2014 using ICD-9 diagnostic codes. The primary outcome of this study was inpatient prevalence of PM/DM in the United States across the span of 10 years. Secondary outcomes included reason for hospitalization, inpatient mortality, morbidity, hospital length of stay (LOS), utilization of specialized procedures/tests and expenditures. A cohort of patients without PM/DM was also identified from the same database to serve as comparators. Multivariate regression analysis was used to adjust for age, sex, ethnicity, comorbidities and hospital characteristics.

RESULTS

A total of 160,528 admissions of patients with a diagnosis of PM/DM occurred in the study period, corresponding to the inpatient prevalence of 41.9 cases per 100,000 discharges. During admission, patients with PM/DM died more frequently than patients without PM/DM with an adjusted odds ratio (aOR) of 2.22 (P<0.01). A significantly higher inpatient morbidity among patients with PM/DM was also observed as indicated by a significantly higher risk of shock (aOR 2.33; P<0.01), acute kidney injury (aOR 1.12; P<0.01), multi-organ failure (aOR 1.83; P<0.01) and need for admission to intensive care unit (aOR 1.94; P<0.01). Patients in the PM/DM had an average of 1.7 more days of LOS (P<0.01). The mean hospital costs and total hospitalization charges for patients with PM/DM were significantly higher than patients without PM/DM with additional adjusted mean of $4,217 and $13,531, respectively, in the multivariate model. Patients with PM/DM underwent computerized tomography scan (aOR 1.90; P<0.01), magnetic resonance imaging (aOR 1.68; P<0.01) and angiography (aOR 1.15; P<0.01) more often than comparators.

CONCLUSIONS

Inpatient prevalence of PM/DM was higher than what would be expected from the overall incidence. Hospitalizations of patients with PM/DM were associated with significantly higher rate of mortality, morbidity and resource utilization.

TLR expression in peripheral monocyte subsets of patients with idiopathic inflammatory myopathies: association with clinical and immunological features

BACKGROUND

Monocytes and toll-like receptors (TLR) have been found in the inflammatory infiltrate of muscle biopsies in patients with idiopathic inflammatory myopathies (IIM), suggesting an important role of these cells in the pathogenesis of myositis. The monocyte subsets, their TLR expression in peripheral blood and their relationship with the clinical characteristics of patients with IIM has not been addressed.

METHODS

We recruited 45 patients with IIM diagnosis and 15 age and sex-adjusted healthy controls. We assessed the disease activity and damage, performed a nailfold capillaroscopy and registered the cardio-pulmonary parameters from the medical charts. Monocyte subsets, their expression of TLR2 and TLR4 and the serum Th1/Th2/Th17 cytokines levels were evaluated by flow cytometry. We expressed quantitative variables as medians and interquartile ranges (IQR) or minimum and maximum (min-max). Differences between groups were assessed with Mann-Whitney U and the Kruskal-Wallis tests. Correlation between quantitative variables was assessed with Spearman Rho.

RESULTS

Twenty-nine patients were women (64.4%) and 32 (71.1%) had dermatomyositis. In comparison to healthy controls, patients with active IIM had a higher percentage of intermediate monocytes and lower amounts of classical monocytes. Patients with IIM had a higher expression of TLR4 in all their monocyte subsets, regardless of disease activity and prednisone treatment. Serum IL-6 correlated with the TLR2 expression in every monocyte subset and the expression of TLR2 in intermediate monocytes was higher among patients with dysphagia. Subjects with nailfold capillaroscopy abnormalities had a higher amount of TLR2+ classical and non-classical monocytes and those with interstitial lung disease (ILD) had a higher percentage of TLR4+ non-classical monocytes. The classical and intermediate monocytes from patients with anti Mi2 antibodies had a higher expression of TLR4. The percentage of intermediate monocytes and the expression of TLR4 in all monocyte subsets showed a good diagnostic capacity in patients with IIM.

CONCLUSION

Patients with IIM have a differential pool of monocyte subsets with an enhanced expression of TLR2 and TLR4, which correlates with disease activity and distinctive clinical features including dysphagia, ILD, vasculopathy, and pro-inflammatory cytokines. These immunological features might be useful as a potential diagnostic tool as well as novel disease activity biomarkers in IIM.

Inflammatory muscle disease - An update

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of inflammatory myopathies whose common feature is immune-mediated muscle injury. There are distinct subgroups including dermatomyositis (DM), polymyositis (PM), inclusion body myositis, and immune-mediated necrotizing myopathy. Antisynthetase syndrome is also emerging as a distinct subgroup with its unique muscle histopathological characteristic of perifascicular necrosis. While the newly updated EULAR/ACR Classification Criteria for IIM have brought advancements in diagnosis and the exclusion of mimickers, the use of only one autoantibody in the derivation of the schema limits its use. Similarly, while the advent of multiple novel therapeutics in the treatment of myositis has been exciting, it has also highlighted the scarcity of validated outcome measures. The purpose of our review is to highlight the updated classification criteria of myositis, newly reported clinical phenotypes associated with myositis autoantibodies, the measurement of outcomes, and emerging treatments in the field.

Prevalence of polymyalgia rheumatica in a cohort of patients with idiopathic inflammatory myopathy

Polymyalgia rheumatica (PMR) is a common rheumatological condition occurring in adults aged over 50 years. The association of PMR with other autoimmune diseases such as rheumatoid arthritis is complex. There is a clear relationship with giant cell arteritis. We sought to determine whether there is any association between PMR and idiopathic inflammatory myopathy (IIM). We undertook a database study of adult patients with a diagnosis of IIM under the care of the Rheumatology Department of the Royal Adelaide Hospital, and retrospectively determined the frequency of PMR in this patient cohort. Patients were considered to have PMR if this had been diagnosed by a physician or if they satisfied all five of the following clinical criteria: (1) bilateral shoulder and/or pelvic girdle aching, (2) morning stiffness exceeding 45 min, (3) age greater than 50 years, (4) duration more than 2 weeks, and (5) evidence of an elevated erythrocyte sedimentation rate or C-reactive protein. Amongst 82 patients with IIM, seven (8.5%) were found to have PMR. There was a disproportionate representation of necrotizing autoimmune myopathy (NAM) in patients with IIM/PMR (5/7) compared with patients with IIM alone (19/75), p = 0.02. There was a high prevalence of antibodies to 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in patients with IIM/PMR (4/7, 57%) compared with those with IIM alone (9/32, 28%), p = 0.19. The prevalence of PMR in our IIM cohort was much higher than the population prevalence 0.91-1.53% and it appears there is a specific association with NAM and anti-HMGCR antibodies. Further studies are required to confirm these findings and explore mechanisms of shared disease susceptibility.Key Points• Idiopathic inflammatory myositis, in particular, statin-associated necrotizing myositis and anti-HMG co-A reductase antibodies, may have a previously unrecognized association with polymyalgia rheumatica.

Aberrant expansion of circulating CD4+ CXCR5+ CCR7lo PD1hi Tfh precursor cells in idiopathic inflammatory myopathy

OBJECTIVE

To determine circulating follicular T helper (Tfh) cell precursor and its relationship with clinical characteristics in idiopathic inflammatory myopathy (IIM).

METHODS

The study population included 47 patients with IIM and 30 healthy controls. Circulating CD4⁺ CXCR5⁺ CCR7^lo PD-1^hi T cells and intracellular interleukin (IL)-21 were assessed by flow cytometry. Serum IL-21 levels were measured by enzyme-linked immunosorbent assay. The disease activity was evaluated using myositis disease activity assessment visual analog scales (VAS) as well as muscle and physician global assessment (PGA).

RESULTS

The percentage of the CCR7^lo PD-1^hi subset cells within CD4⁺ CXCR5⁺ T cells was significantly increased in patients with IIM compared to that in healthy controls (14.3 ± 6.5 vs 11.4 ± 2.6, P = .009). Patients with higher percentages of CCR7^lo PD-1^hi subsets presented with higher PGA VAS (P = .000), muscle VAS (P = .000), as well as serum creatinine kinase (CK) levels (P = .000) than those with lower percentages of CCR7^lo PD-1^hi subsets. IL-21 expression significantly increased in CD4⁺ CXCR5⁺ CCR7^lo PD-1^hi T cells in patients with IIM compared to that in healthy controls (26.07 ± 7.38 vs 19.25 ± 5.67, P = .001). Meanwhile, both the CCR7^lo PD-1^hi subset and intracellular IL-21 expression in IIM patients showed significantly positive correlation with PGA VAS, muscle VAS and serum CK levels. Circulating CD4⁺ CXCR5⁺ CCR7^lo PD-1^hi T cells and intracellular IL-21 decreased significantly when disease was improved (P = .018; P = .028).

CONCLUSION

The percentage of circulating CCR7^lo PD-1^hi subset among total CD4⁺ CXCR5⁺ T cells and intracellular IL-21 expression expanded and showed significant correlation with disease activity in IIM. The circulating follicular helper T cell precursor may be involved in the pathogenesis, especially muscle injury in IIM.

Biologic therapy in the idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases resulting from inflammation of muscle and manifesting as weakness, though a range of extra-muscular manifestations are observed. These are often correlated closely with disease subtype and the presence of myositis-specific/myositis-associated antibodies. IIM are notoriously difficult to treat and often refractory to glucocorticoid therapy and synthetic immunosuppressants. Both the innate and adaptive immune systems are implicated in the pathogenesis of IIM. A growing understanding of the key cytokines as well as the cell-mediated and antibody effectors of disease has identified multiple potential targets for biologic therapy. The most widely used of these is B-cell depletion via rituximab though the tumour necrosis factor inhibitors and other biologic therapies used in diseases such as rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis have also been trialled. This review summarises the literature thus far on biologic therapy in IIM, highlighting both the significant trials that influence current treatment regimens and also the continuing need for further research to inform more effective therapies.

Coexistence of anti-Jo1 and anti-signal recognition particle antibodies in a polymyositis patient

Idiopathic inflammatory myopathies are a heterogeneous group of potentially treatable myopathies. They are classified, on the basis of clinical and histopathological features, into four subtypes: dermatomyositis, polymyositis, necrotizing autoimmune myositis and inclusion-body myositis. Myositis-associated antibodies and myositis-specific autoantibodies are frequently found in patients with idiopathic inflammatory myopathies, and are useful in the diagnosis and classification. Anti-histidyl transfer RNA synthetase antibody is the most widely prevalent and is highly specific for polymyositis. Signal recognition particle antibody is also a specific autoantibody for polymyositis, but it is infrequent and rarely found in patients having other myositis-specific autoantibodies. We present a man with polymyositis who had both antibodies in serum, which is considered an extremely rare clinical situation. Here we analyze the clinical course and findings, and examine the effect of the coexistence and possible interaction on prognosis.

Expression of interleukin-18 in muscle tissue of patients with polymyositis or dermatomyositis and effects of conventional immunosuppressive treatment

Objectives

To investigate the expression of IL-18 in symptomatic and asymptomatic muscle tissues of patients with PM and DM and the effects of conventional immunosuppressive treatment on such expression.

Methods

Two cohorts of patients were included in this study. The first cohort consisted of 10 new-onset myositis patients. IL-18 expression was compared between symptomatic and asymptomatic muscle biopsies that were taken prior to treatment. The second cohort consisted of another 10 patients with repeated muscle biopsies before and after 8 months with conventional immunosuppressive treatment. Using immunohistochemistry, IL-18 expression in muscle tissues was compared before and after treatment. Biopsies from seven healthy individuals were included as controls.

Results

IL-18 expression was predominantly localized to inflammatory cells and capillaries in patients and mostly to capillaries in healthy controls. Total IL-18 expression in muscle tissues from the new-onset patients, at both symptomatic and asymptomatic sites, was significantly higher compared with healthy controls (P = 0.007 and P = 0.002) with no statistical difference in appearances between symptomatic and asymptomatic sites. The number of IL-18 positive capillaries was not different among symptomatic, asymptomatic and healthy muscles. Total IL-18 expression appeared lower in biopsies from patients receiving and improving with immunosuppressive treatment, particularly the number of IL-18 positive inflammatory cells but not the number of IL-18 positive capillaries, which was consistent with significantly decreased expression of CD68+ macrophages (P = 0.04).

Conclusion

IL-18 is highly expressed in muscle tissue in the context of inflammatory myopathies and based on its plausible effector functions could provide a novel therapeutic target in future.

The clinical and histopathological features of idiopathic inflammatory myopathies with asymmetric muscle involvement

The objective is to determine the frequency of idiopathic inflammatory myopathies (IIMs) with asymmetric muscle involvement (IIMs-A) as initial manifestations in total IIMs and to compare the demographic, clinical, histopathological and radiological characteristics of IIMs-A with classical IIMs (IIMs-C). We retrospectively reviewed the clinical, laboratory, muscle images, histopathological features and treatment response of patients at the Qilu hospital who were diagnosed as IIMs from April 2005 to August 2017. We found among 134 IIMs patients, 13(9.2%) patients with IIMs-A were identified, of which 7 patients were diagnosed as dermatomyositis (DM), 2 as polymyositis (PM), 4 as immune-mediated necrotizing myopathy (IMNM) using the European Neuromuscular Centre (ENMC) criteria. The mean age of our group was 59.1 years old. The duration from the initial symptoms to the first examination was less than 12 months in 12 patients (92.3%). 46.2% patients accompanied with weakness of distal limbs and bulbar symptoms. Finger flexion involvement was found in 5 patients (38.5%). There was no patient that finger flexion was weaker than shoulder abduction. The creatine kinase (CK) level in the serum ranged from 41 IU/L to 9125 IU/L (average: 3192.7 ± 2769.9 IU/L). Serum positive anti-mitochondrial antibodies (AMAs) were found in four patients (30.8%). Endomysial fibrosis and inflammatory cell infiltration were detected in 92.3%, 84.6% patients respectively. Mitochondrial abnormalities in histopathological finding of muscle biopsy were seen in 100% cases. The major histocompatibility complex class I (MHC-I) (84.6%) and class II (MHC-II) (92.3%) expressed on muscle biopsies from almost all cases of our patients. MAC antibody, however, was detected in only 20-40% patients. Eight patients (61.5%) had favorable outcomes. The conclusion was that IIMs-A presented mainly in DM, generally with mitochondrial abnormality and highly positive AMAs. The relationship between the presence of AMAs and the asymmetric muscle involvement in DM needs to be further clarified. We should also consider the diagnosis of IIMs when the patient has features of positive AMAs and asymmetric muscle involvement.

Integrated comparison of the miRNAome and mRNAome in muscles of dermatomyositis and polymyositis reveals common and specific miRNA–mRNAs

Aim: Dermatomyositis (DM) and polymyositis (PM) are refractory systemic autoimmune diseases with unknown pathogenesis. miRNAs is an important epigenetic mechanism to regulate gene expression. Methods: We performed whole miRNAs analysis, transcription analysis and the association between miRNAome and mRNAome. Results: For transcription and miRNAs analysis, there were common and specific mRNAs and miRNAs in the muscles of DM and PM. Among them, the expression levels of miR-196a-5p and CPM were negatively correlated in PM, miR-193b-3p and NECAP2 were negatively correlated in DM and PM. Protein carboxypeptidase M (CPM) plays roles in the degradation of extracellular proteins and in the migration and invasion of cancer cells, and protein NECAP2 plays roles in adaptor protein AP-1-mediated fast recycling from early endosomes. The functions of them in the pathogenesis of DM/PM need further studies. Conclusion: Our study identified and confirmed differentially miRNAs and mRNAs in DM and PM. Our observations have laid the groundwork for further diagnostic and mechanistic studies of DM and PM.

Effect of Genetic and Laboratory Findings on Clinical Course of Antisynthetase Syndrome in a Hungarian Cohort

The aim of this study was to determine the clinical, serological, and genetic features of anti-Jo-1 positive antisynthetase patients followed by a Hungarian single centre to identify prognostic markers, which can predict disease phenotypes and disease progression. It was a retrospective study using clinical database of 49 anti-Jo-1 positive patients. 100% of patients exhibited myositis, 73% interstitial lung disease, 88% arthritis, 65% Raynaud's phenomenon, 43% fever, 33% mechanic's hand, and 12% dysphagia. We could detect significant correlation between anti-Jo-1 titer and the CK and CRP levels at disease onset and during disease course. HLA DRB1⁎03 positivity was present in 68.96% of patients, where the CK level at diagnosis was significantly lower compared to the HLA DRB1⁎03 negative patients. HLA DQA1⁎0501-DQB1⁎0201 haplotype was found in 58.62% of patients, but no significant correlation was found regarding any clinical or laboratory features. Higher CRP, ESR level, RF positivity, and the presence of fever or vasculitic skin lesions at the time of diagnosis indicated a higher steroid demand and the administration of higher number of immunosuppressants during the follow-up within anti-Jo-1 positive patients. The organ involvement of the disease was not different in HLA-DRB1⁎0301 positive or negative patients who were positive to the anti-Jo-1 antibody; however, initial CK level was lower in HLA-DRB1⁎0301 positive patients. Distinct laboratory and clinical parameters at diagnosis could be considered as prognostic markers.

Current Treatment for Myositis

PURPOSE OF REVIEW

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.

RECENT FINDINGS

Glucocorticoid (GC) in high doses is still the first-line treatment of patients with myositis. There is a general recommendation to combine GCs with another immunosuppressive agent in the early phase of disease to better control disease activity and possibly to reduce the risk for GC-related side effects. Furthermore, combining pharmacological treatment with individualized and supervised exercise can be recommended based on evidence. There is some evidence for the effect of rituximab in patients with certain myositis-specific autoantibodies, whereas other biologic agents are currently being tested in clinical trials.

SUMMARY

Immunosuppressive treatment in combination with exercise is recommended for patients with myositis to reduce disease activity and improve muscle performance. Subgrouping of patients into clinical and serological subtypes may be a way to identify biomarkers for response to specific immunosuppressive and biological agents and should be considered in future trials.

The roles of neutrophil serine proteinases in idiopathic inflammatory myopathies

Background

Dermatomyositis and polymyositis are the best known idiopathic inflammatory myopathies (IIMs). Classic histopathologic findings include the infiltration of inflammatory cells into muscle tissues. Neutrophil serine proteinases (NSPs) are granule-associated enzymes and play roles in inflammatory cell migration by increasing the permeability of vascular endothelial cells. In this study, we aimed to find the roles of NSPs in pathogenesis of IIMs.

Methods

RNA and DNA were isolated to measure the relative expression of NSPs and their methylation levels. The expression of NSPs in serum and muscle tissues was tested by enzyme-linked immunosorbent assay, immunohistochemistry, and immunofluorescence, respectively. Serum from patients was used to culture the human dermal microvascular endothelial cells (HDMECs), and then we observed the influence of serum on expression of VE-cadherin, endothelial cell tube formation, and transendothelial migration of peripheral blood mononuclear cells (PBMCs).

Results

We found that the expression of NSPs was increased in PBMCs, serum, and muscle tissues of IIM patients; these NSPs were hypomethylated in the PBMCs of patients. Serum NSPs were positively correlated with clinical indicators of IIM patients, including lactic dehydrogenase, erythrocyte sedimentation rate, C-reactive protein, immunoglobulin G, immunoglobulin M, and immunoglobulin A. Patients with anti-Jo-1, with anti-Ro-52, or without interstitial lung disease had lower levels of proteinase 3. Serum NSPs degraded the VE-cadherin of HDMECs, and serum NSP application increased the permeability of HDMECs.

Conclusions

Our studies indicate, for the first time, that NSPs play an important role in muscle inflammatory cell infiltration by increasing the permeability of vascular endothelial cells in IIM patients.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1632-x) contains supplementary material, which is available to authorized users.

Targeted lipidomics analysis identified altered serum lipid profiles in patients with polymyositis and dermatomyositis

BACKGROUND

Polymyositis (PM) and dermatomyositis (DM) are severe chronic autoimmune diseases, characterized by muscle fatigue and low muscle endurance. Conventional treatment includes high doses of glucocorticoids and immunosuppressive drugs; however, few patients recover full muscle function. One explanation of the persistent muscle weakness could be altered lipid metabolism in PM/DM muscle tissue as we previously reported. Using a targeted lipidomic approach we aimed to characterize serum lipid profiles in patients with PM/DM compared to healthy individuals (HI) in a cross-sectional study. Also, in the longitudinal study we compared serum lipid profiles in patients newly diagnosed with PM/DM before and after immunosuppressive treatment.

METHODS

Lipidomic profiles were analyzed in serum samples from 13 patients with PM/DM, 12 HI and 8 patients newly diagnosed with PM/DM before and after conventional immunosuppressive treatment using liquid chromatography tandem mass spectrometry (LC-MS/MS) and a gas-chromatography flame ionization detector (GC-FID). Functional Index (FI), as a test of muscle performance and serum levels of creatine kinase (s-CK) as a proxy for disease activity were analyzed.

RESULTS

The fatty acid (FA) composition of total serum lipids was altered in patients with PM/DM compared to HI; the levels of palmitic (16:0) acid were significantly higher while the levels of arachidonic (20:4, n-6) acid were significantly lower in patients with PM/DM. The profiles of serum phosphatidylcholine and triacylglycerol species were changed in patients with PM/DM compared to HI, suggesting disproportionate levels of saturated and polyunsaturated FAs that might have negative effects on muscle performance. After immunosuppressive treatment the total serum lipid levels of eicosadienoic (20:2, n-6) and eicosapentaenoic (20:5, n-3) acids were increased and serum phospholipid profiles were altered in patients with PM/DM. The correlation between FI or s-CK and levels of several lipid species indicate the important role of lipid changes in muscle performance and inflammation.

CONCLUSIONS

Serum lipids profiles are significantly altered in patients with PM/DM compared to HI. Moreover, immunosuppressive treatment in patients newly diagnosed with PM/DM significantly affected serum lipid profiles. These findings provide new evidence of the dysregulated lipid metabolism in patients with PM/DM that could possibly contribute to low muscle performance.

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.

Quantitative 3D scintigraphy shows increased muscular uptake of pyrophosphate in idiopathic inflammatory myopathy

BACKGROUND

Nuclear imaging is increasingly being used in the diagnostic work-up of idiopathic inflammatory myopathy (IIM). Increased muscular uptake of technetium-99m-pyrophosphate (^99mTc-PYP) has hitherto been assessed qualitatively by planar scintigraphy. We set out to perform quantitative tomographic scintigraphy in IIM.

RESULTS

Ninety IIM patients and 48 control subjects underwent ^99mTc-PYP single-photon emission computed tomography (SPECT)/CT of the upper and lower body. Scans were evaluated visually by an intensity score (1-4) and quantitatively by the mean standardized uptake value (SUV_mean) in thigh muscles after semi-automated segmentation of these. Furthermore, a SUV_mean gradient down along the thighs was determined by linear regression of the slice-by-slice activity. Interobserver analyses were performed on qualitative evaluations. Compared to controls, patients more often had a high intensity score (p < 0.0001), but interobserver analyses revealed only moderate agreement. The thigh muscular ^99mTc-PYP activity (SUV_mean) was 60% higher in patients than in controls, p < 0.0001, albeit with a wide range. There was an activity gradient down the thigh muscle, the proximal tracer uptake being highest, and this gradient was steeper in patients than in controls; the activity decreased by 0.00024 and 0.00010 SUV_mean mm^-1, respectively, along the thighs.

CONCLUSIONS

The muscular uptake of ^99mTc-PYP was significantly higher in patients than in healthy controls by qualitative and quantitative assessment. The tracer uptake was higher in the proximal than in the distal part of the thigh muscle, and SUV_mean gradients differed between groups. Hence, tomographic nuclear imaging allowing for quantification of the ^99mTc-PYP uptake might contribute to the diagnosis of IIM, and SPECT/CT of the lower body might suffice.

Effect of endurance exercise on microRNAs in myositis skeletal muscle-A randomized controlled study

OBJECTIVE

To identify changes in skeletal muscle microRNA expression after endurance exercise and associate the identified microRNAs with mRNA and protein expression to disease-specific pathways in polymyositis (PM) and dermatomyositis (DM) patients.

METHODS

Following a parallel clinical trial design, patients with probable PM or DM, exercising less than once a week, and on stable medication for at least one month were randomized into two groups at Karolinska University Hospital: a 12-week endurance exercise group (n = 12) or a non-exercised control group (n = 11). Using an Affymetrix microarray, microRNA expression was determined in paired muscle biopsies taken before and after the exercise intervention from 3 patients in each group. Ingenuity pathway analysis with a microRNA target filter was used to identify microRNA transcript targets. These targets were investigated at the mRNA (microarray) and protein (mass spectrometry) levels in patients.

RESULTS

Endurance exercise altered 39 microRNAs. The microRNAs with increased expression were predicted to target transcripts involved in inflammatory processes, metabolism, and muscle atrophy. Further, these target transcripts had an associated decrease in mRNA expression in exercised patients. In particular, a decrease in the NF-κB regulator IKBKB was associated with an increase in its target microRNA (miR-196b). At the protein level, there was an increase in mitochondrial proteins (AK3, HIBADH), which were associated with a decrease in microRNAs that were predicted to regulate their expression.

CONCLUSION

Improvement in disease phenotype after exercise is associated with increasing microRNAs that target and downregulate immune processes at the transcript level, as well as decreasing microRNAs that target and upregulate mitochondrial content at the protein level. Therefore, microRNAs may improve disease by decreasing immune responses and increasing mitochondrial biogenesis.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01184625.

Clinical Profiles and Prognosis of Patients with Distinct Antisynthetase Autoantibodies

OBJECTIVE

To compare the clinical characteristics and identify the longterm outcomes of Chinese patients with different antisynthetase antibodies.

METHODS

We investigated retrospectively 124 consecutive patients with antisynthetase syndrome. Medical records, laboratory results, and computed tomography images were obtained.

RESULTS

The antisynthetase antibodies we investigated were anti-Jo1 (n = 62), anti-PL7 (n = 31), anti-PL12 (n = 12), and anti-EJ (n = 19). The overall prevalence of interstitial lung disease (ILD) reached 94.4% among study patients. Eleven patients (8.9%) developed rapidly progressive ILD (RP-ILD). Eight patients (6.5%) experienced malignancy. RP-ILD was statistically more prevalent in patients with antisynthetase syndrome with anti-PL7 than those without anti-PL7 (p = 0.028). Anti-Ro52-positive patients with antisynthetase syndrome experienced higher frequency of RP-ILD than those without anti-Ro52 (p = 0.001). Further, anti-PL7-positive patients coexisting with anti-Ro52 exhibited more RP-ILD than those without anti-Ro52 (p = 0.001). Patients with antisynthetase syndrome with RP-ILD had a higher proportion of neutrophils in bronchoalveolar lavage fluid and serum ferritin than those without RP-ILD (p = 0.006 and p = 0.013, respectively). Although no differences were observed between the Kaplan-Meier curves of the 4 antisynthetase antibodies subgroups (p = 0.349), the survival rate of patients with anti-PL7 decreased more rapidly in the early stage of longterm followup compared with those with other antisynthetase antibodies. The presence of RP-ILD, malignancy, and elevated serum ferritin was identified to be associated with poor prognosis in patients with antisynthetase syndrome.

CONCLUSION

Our study investigates the clinical phenotypes and outcomes of patients with antisynthetase syndrome with distinct antisynthetase antibodies and highlights the link between the anti-PL7 antibody and RP-ILD.

Diagnosis and Management of Immune-Mediated Myopathies

Immune-mediated myopathies (IMMs) are a heterogeneous group of acquired muscle disorders characterized by muscle weakness, elevated creatine kinase levels, and myopathic electromyographic findings. Most IMMs feature the presence of inflammatory infiltrates in muscle. However, the inflammatory exudate may be absent. Indeed, necrotizing autoimmune myopathy (NAM), also called immune-mediated necrotizing myopathy, is characterized by a necrotizing pathologic process with no or minimal inflammation in muscle. The recent discovery of antibodies associated with specific subtypes of autoimmune myopathies has played a major role in characterizing these diseases. Although diagnostic criteria and classification of IMMs currently are under revision, on the basis of the clinical and muscle histopathologic findings, IMMs can be differentiated as NAM, inclusion body myositis (IBM), dermatomyositis, polymyositis, and nonspecific myositis. Because of recent developments in the field of NAM and IBM and the controversies around polymyositis, this review will focus on NAM, IBM, and dermatomyositis.