A Comprehensive Overview on Myositis-Specific Antibodies: New and Old Biomarkers in Idiopathic Inflammatory Myopathy

Correlation between B-cell epitope profile and clinical features of anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive (MDA5+) dermatomyositis patients exhibit a variety of clinical features. We therefore investigated whether patterns of B-cell epitope recognition are linked to the clinical course of MDA5+ dermatomyositis.

METHODS

Our cross-sectional study used ELISA-based methods to determine the relationship between antibody recognition of overlapping 155 amino acid MDA5 subfragments and clinical features of 24 MDA5+ myositis patients. Correlations between clinical features and standardized anti-MDA5 subfragment antibody titres were assessed via Spearman's rank correlation coefficients.

RESULTS

Twenty-four MDA5+ patients submitted serum samples within a median of 0 (interquartile range, 0-74) days from the initial clinic visit. In addition to typical dermatomyositis rashes, these patients exhibited muscle symptoms (n = 11), vascular dysfunction (n = 9) and interstitial lung disease (ILD) (n = 16). Female patients exhibited higher titres of antibodies recognizing fragment H (aa 905-1026) compared with male patients. Muscle involvement was associated with higher levels of anti-fragment F (aa 646-801) antibody. Conversely, patients with vascular abnormalities had higher anti-fragment B (aa 130-284) and E (aa 517-671) antibody titres than those without vascular dysfunction. Four patients died due to ILD progression and showed higher anti-fragment A (aa 1-155) antibody titres than the other 20 patients. Differences in the ratio of anti-fragment to anti-full-length MDA5 antibody titres were found for sex (H: anti-MDA5) and vascular dysfunction (anti-fragment B, E: anti-MDA5).

CONCLUSIONS

Various clinical features of MDA5+ dermatomyositis correlated with levels of antibodies targeting selected subfragments of this autoantigen, providing a link between fragment-specific immune responses and disease course.

Clinical profiles and treatment outcomes of outpatients with interstitial lung disease and mechanic's hands: A retrospective and observational cohort

Idiopathic inflammatory myopathies, especially antisynthetase syndrome, often appear outside of the muscles as interstitial lung disease (ILD). Another typical finding is the presence of mechanic's hands. The aim of the present study was to describe the clinical, functional, tomographic, and serological data of patients with ILD and mechanic's hands and their response to treatment and survival rates. This is a retrospective study of ILD with concurrent myopathy. Among the 119 patients initially selected, 51 had mechanic's hands. All the patients were screened for anti-Jo-1 antibodies. An expanded panel of myopathy autoantibodies was also performed in 27 individuals. Of the 51 patients, 35 had 1 or more antibodies. The most common were anti-Jo-1, anti-PL-7, and anti-PL-12, while of the associated antibodies, anti-Ro52 was present in 70% of the 27 tested individuals. A significant response to treatment was characterized by an increase in predicted forced vital capacity (FVC) of at least 5% in the last evaluation done after 6 to 24 months of treatment. A decrease in predicted FVC of at least 5%, the need for oxygen therapy, or death were all considered treatment failures. All patients were treated with corticosteroids, and 71% with mycophenolate. After 24 months, 18 patients had an increase in FVC, 11 had a decrease, and 22 remained stable. After a median follow-up of 58 months, 48 patients remained alive and three died. Patients with honeycombing on high-resolution chest tomography (log-rank = 34.65; P < .001) and a decrease in FVC ≥5% (log-rank = 18.28, P < .001) had a poorer survival rate. Patients with ILD and mechanic's hands respond well to immunosuppressive treatment.

FAPi PET/CT for assessment and visualisation of active myositis-related interstitial lung disease: a prospective observational pilot study

Background

Interstitial lung disease (ILD) is a common manifestation of idiopathic inflammatory myopathies (IIM) and a substantial contributor to hospitalisation, increased morbidity, and mortality. In-vivo evidence of ongoing tissue remodelling in IIM-ILD is scarce. We aimed to evaluate fibroblast activation in lungs of IIM-patients and control individuals using ⁶⁸Ga-labelled inhibitor of Fibroblast-Activation-Protein (FAPi) based positronic emission tomography and computed tomography imaging (PET/CT).

Methods

In this prospective observational pilot study, consecutive patients with IIM and participants without rheumatic conditions or ILD serving as a control group were recruited at the Medical University of Vienna, Austria, and underwent FAPi PET/CT imaging. Standard-of-care procedures including clinical examination, assessment of severity of dyspnoea, high-resolution computed tomography (HR-CT), and pulmonary function testing (PFT) were performed on all patients with IIM at baseline and for patients with IIM-ILD at follow-up of 12 months. Baseline pulmonary FAPi-uptake was assessed by the maximum (SUVmax) and mean (SUVmean) standardized uptake values (SUV) over the whole lung (wl). SUV was corrected for blood pool background activity and target-to-background ratios (TBR) were calculated. We compared pulmonary FAPi-uptake between patients with IIM-ILD and those without ILD, as well as controls, and correlated baseline FAP-uptake with standard diagnostic tools such as HR-CT and PFT. For predictive implications, we investigated whether patients with IIM and progressive ILD exhibited higher baseline FAPi-uptake compared to those with stable ILD. Metrics are reported as mean with standard deviation (±SD).

Findings

Between November 16, 2021 and October 10, 2022, a total of 32 patients were enrolled in the study. Three participants from the control group were excluded due to cardiopulmonary disease. In individuals with IIM-ILD (n = 14), wlTBRmax and wlTBRmean were significantly increased as compared with both non-ILD-IIM patients (n = 5) and the control group (n = 16): wlTBRmax: 2.06 ± 1.04 vs. 1.04 ± 0.22 (p = 0.019) and 1.08 ± 0.19 (p = 0.0012) and wlTBRmean: 0.45 ± 0.19 vs. 0.26 ± 0.06 (p = 0.025) and 0.27 ± 0.07 (p = 0.0024). Similar values were observed in wlTBRmax or wlTBRmean between non-ILD IIM patients and the control group. Patients with progressive ILD displayed significantly enhanced wlTBRmax and wlTBRmean values at baseline compared to patients with stable ILD: wlTBRmax: 1.30 ± 0.31 vs. 2.63 ± 1.04 (p = 0.0084) and wlTBRmean: 0.32 ± 0.08 vs. 0.55 ± 0.19 (p = 0.021). Strong correlations were found between FAPi-uptake and disease extent on HR-CT (wlTBRmax: R = 0.42, p = 0.07; wlTBRmean: R = 0.56, p = 0.013) and severity of respiratory symptoms determined by the New York Heart Association (NYHA) classification tool (wlTBRmax: R = 0.52, p = 0.022; wlTBRmean: R = 0.59, p = 0.0073). Further, pulmonary FAPi-uptake showed inverse correlation with forced vital capacity (FVC) (wlTBRmax: R = -0.56, p = 0.012; wlTBRmean: R = -0.64, p = 0.0033) and diffusing capacity of the lungs for carbon monoxide (DLCO) (wlTBRmax: R = -0.52, p = 0.028; wlTBRmean: R = -0.68, p = 0.0017).

Interpretation

Our study demonstrates higher fibroblast activation in patients with IIM-ILD compared to non-ILD patients and controls. Intensity of pulmonary FAPi accumulation was associated with progression of ILD. Considering that this study was carried out on a small population, FAPi PET/CT may serve as a useful non-invasive tool for risk stratification of lung disease in IIM.

Funding

The Austrian Research Fund.

Anti-nuclear matrix protein 2 antibody-positive amyopathic dermatomyositis presenting in a patient with prostate cancer: A case report

Nuclear matrix protein (NXP-2) positive amyopathic dermatomyositis (DM) may present without classic symptoms like muscle weakness, dysphagia, and edema, and mimic conditions like cutaneous lupus. Given DM's association with malignancy and interstitial lung disease, prompt and accurate diagnosis is important. Testing for myositis-specific antibodies aids diagnosis in ambiguous cases.

Autoantibody evaluation in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM), generally referred to as myositis is a heterogeneous group of diseases characterized by muscle inflammation and/or skin involvement, diverse extramuscular manifestations with variable risk for malignancy and response to treatment. Contemporary clinico-serologic categorization identifies 5 main clinical groups which can be further stratified based on age, specific clinical manifestations and/or risk for cancer. The serological biomarkers for this classification are generally known as myositis-specific (MSAs) and myositis-associated antibodies. Based on the use of these antibodies, IIM patients are classified into anti-synthetase syndrome, dermatomyositis, immune-mediated necrotizing myopathy, inclusion body myositis, and overlap myositis. The current classification criteria for IIM requires clinical findings, laboratory measurements, and histological findings of the muscles. However, the use MSAs and myositis-associated autoantibodies as an adjunct for disease evaluation is thought to provide a cost-effective personalized approach that may not only guide diagnosis but aid in stratification and/or prognosis of patients. This review provides a comprehensive overview of contemporary autoantibodies that are specific or associated myositis. In addition, it highlights possible pathways for the detection and interpretation of these antibodies with limitations for routine clinical use.

Prognostic factors of fungal infection in anti-melanoma differentiation-associated gene 5 antibody-positive associated interstitial lung disease

OBJECTIVE

To investigate the potential risk factors for mortality in fungal infection in anti-melanoma differentiation-associated gene 5 antibody-positive associated interstitial lung disease (MDA5-ILD).

METHODS

Patients diagnosed with MDA5-ILD from April 2017 to November 2022 were included. The demographic data, laboratory examinations, therapeutic and follow-up information were recorded. Fungal infection diagnosis was established based on a combinations of host factors, clinical features and mycologic evidences. High-dose corticosteroid therapy was defined as the initial corticosteroid doses > 240mg/d. The primary endpoint was mortality. Potential factors for fungal infection occurrence and prognostic factors were analyzed using logistic regression analysis and Cox proportional hazards regression.

RESULTS

In total, 121 patients with MDA5-ILD were included. During follow-up, 41 (33.9%) patients had suffered fungal infection and 39.0% (16/41) of whom had ever received high-dose corticosteroid therapy. The median interval from corticosteroid use to the occurrence of fungal infection was 29 (10-48) days. The mean survival time of patients with fungal infection was 234.32 ± 464.76 days. The mortality in MDA5-ILD with fungal infection was 85.4% (35/41), which was significantly higher than those without (85.4% VS 56.3%, P < 0.001). High-dose corticosteroid therapy (P = 0.049) was independent risk factor for fungal infection occurrence. Decreased serum albumin level (P = 0.024) and high-dose corticosteroid therapy (P = 0.008) were both associated with increased mortality in MDA5-ILD patients with fungal infection.

CONCLUSION

Fungal infection is associated with an increased mortality in MDA5-ILD. The serum albumin level and corticosteroid dose should be taken into consideration when treating MDA5-ILD. Key Points • This study showed fungal infection is associated with an increased mortality in MDA5-ILD. In MDA5-ILD patients with fungal infection, the presence of decreased serum albumin level and high-dose corticosteroid therapy were identified as predictors for mortality.

Predicting the death of patients with anti-melanoma differentiation-associated protein-5-positive dermatomyositis-associated interstitial lung disease: A systematic review and meta-analysis

OBJECTIVES

To investigate the risk factors for death in anti-melanoma differentiation-associated protein-5-positive dermatomyositis-associated interstitial lung disease (ILD).

METHODS

Studies were identified by searching PubMed, Embase, Web of Science, and Cochrane Library. We calculated pooled risk ratios (RRs) or standardized mean differences (SMDs) and 95% confidence intervals (CIs) using random-effects models.

RESULTS

Twenty studies were selected. Factors that may increase death risk included older age (SMD: 0.62, 95% CI: 0.42-0.81), elevated Krebs von den Lungen-6 (SMD: 0.66, 95% CI: 0.47-0.86), lactate dehydrogenase (SMD: 0.87, 95% CI: 0.72-1.02), C-reactive protein (SMD: 0.62, 95% CI: 0.44-0.80), ferritin (SMD: 0.93, 95% CI: 0.71-1.15), creatine kinase (SMD: 0.28, 95% CI: 0.13-0.44), neutrophil (SMD: 0.34, 95% CI: 0.04-0.64), neutrophil-to-lymphocyte ratio (SMD: 0.52, 95% CI: 0.24-0.79), aspartate aminotransferase (SMD: 0.70, 95% CI: 0.45-0.94), shorter disease duration (SMD: -0.44, 95% CI: -0.67 to -0.21), rapidly progressive ILD (RR: 4.08, 95% CI: 3.01-5.54), fever (RR: 1.98, 95% CI: 1.46-2.69), dyspnoea (RR: 1.63, 95% CI: 1.32-2.02), and anti-Ro52 antibody positive (RR: 1.28, 95% CI: 1.11-1.49). Female (RR: 0.86, 95% CI: 0.78-0.94), increased albumin (SMD: -1.20, 95% CI: -1.76 to -0.64), lymphocyte (SMD: -0.49, 95% CI: -0.67 to -0.30), and arthralgia (RR: 0.53, 95% CI: 0.37-0.78) were protective factors.

CONCLUSION

Older age, shorter disease duration, rapidly progressive ILD, fever, dyspnoea, anti-Ro52 antibody positive, and some inflammatory markers were risk factors for death in patients with anti-melanoma differentiation-associated protein-5-positive dermatomyositis-associated ILD.

Dermatomyositis: Practical Guidance and Unmet Needs

Dermatomyositis is a heterogeneous idiopathic inflammatory myopathy associated with various cutaneous manifestations and variable presence of myositis, interstitial lung disease, and other visceral organ involvement. An accurate diagnosis of dermatomyositis requires correlating clinical examination findings with serological and histological findings. Familiarity with pathognomonic and common cutaneous manifestations of dermatomyositis, which are highlighted here, can be especially helpful in making an accurate diagnosis. Additionally, evaluating patients for presence of myositis-specific autoantibodies can further support or refute a dermatomyositis diagnosis. When present, myositis-specific autoantibodies can also help guide workups for various dermatomyositis-associated manifestations, as each is associated with relatively distinct clinical characteristics. Evaluating patients for various systemic manifestations often relies on expert opinion recommendations; however, societal guideline statements concerning the evaluation of some manifestations have recently been described. Although malignancy-associated dermatomyositis is a well-accepted subtype, there is limited evidence to support extensive malignancy screening has a favorable benefit-risk ratio in most dermatomyositis patients. However, recent research has uncovered novel associations between dermatomyositis and malignancy, suggesting the possibility of identifying high-risk subsets of dermatomyositis patients in whom malignancy screening may have a high value. Treatment for dermatomyositis has remained largely unchanged over the past several decades. Although many dermatomyositis patients can be effectively treated with current options, either as monotherapy or with combination regimens, there is a need for more targeted and effective DM therapies, in general, and for MDA5(+) dermatomyositis-associated rapidly progressive interstitial lung disease. Fortunately, significant current and emerging research activities evaluating various novel medications for dermatomyositis provide hope for exciting future advances in patients with this intriguing immune-mediated disease.

[Pulmonary involvement in idiopathic inflammatory myopathies]

Idiopathic inflammatory myopathies are rare systemic diseases with different types of pulmonary manifestations depending on the underlying aetiology; here, interstitial lung diseases (ILD) are the most frequently found patterns depending on the underlying disorder. There is a lack of sufficient prospective studies on this heterogeneous group of patients, particularly in case of ILD being involved. The diagnosis is based upon guideline recommendations for ILD and requires a multidisciplinary discussion within a team with specific expertise in this field. Myositis specific antibodies and myositis associated antibodies form an essential part of the diagnostic tools and may also be associated with a certain phenotype or disease progression. Anti-t-RNA-synthetase antibodies (Anti-ARS) and anti-melanoma differentiation-associated gene 5 antibodies (MDA5) play an important clinical role for treatment the estimation of response and prognosis. The most common ILD patterns are nonspecific interstitial pneumonia (NSIP) and organising pneumonia (OP) or a mixed pattern of both. Treatment is based on systemic steroids and early initiation of other immunosuppressant drugs. Evidence for this is, however, sparse, since most of the studies having investigated treatment modalities are of retrospective nature, even though some new prospective data may be useful for the establishment of treatment pathways in the future.

Anti-TIF1γ-Dermatomyositis and Sjögren's Syndrome As the Inaugural Presentation for Rectal Cancer

Dermatomyositis (DM) is an inflammatory myopathy often paraneoplastic in nature. Patients have characteristic cutaneous findings and possible muscle involvement. In the latter, muscle enzymes are elevated, and the electromyogram shows varied changes. Muscle or skin biopsy and myositis-specific antibodies confirm the diagnosis. Here, we report the case of an 86-year-old woman with cutaneous lesions, proximal weakness, and sicca symptoms. Muscle enzymes and electromyogram were normal. Antinuclear antibodies were elevated, and anti-TIF1γ and anti-Ro52 antibodies were positive. Muscle biopsy was compatible with the diagnosis of DM, and salivary gland biopsy confirmed Sjögren's syndrome. Malignancy investigation identified a rectal cancer, which was resected. This case illustrates a rare form of cancer presentation - anti-TIF1γ DM with normal muscle enzymes and electromyogram and concomitant secondary Sjögren's syndrome. Malignancy screening and multidisciplinary management were crucial to a successful approach.

Fatty infiltration in the posterior muscles of the lower extremities as an MRI feature in antimitochondrial antibody-associated myopathy

OBJECTIVE

Idiopathic inflammatory myopathy (IIM) with antimitochondrial M2 antibody (AMA-M2) has been associated with distinct clinical characteristics. In this study, we explore the magnetic resonance imaging (MRI) findings of the muscles of the lower extremities in AMA-M2-positive IIM to gain more insight.

METHODS

MRI of 22 lower extremity muscles was retrospectively evaluated in 14 patients with AMA-M2-positive IIM and 37 age- and sex-matched patients with AMA-M2-negative IIM. Muscles with inflammatory edema and fatty infiltration were assessed according to the Stramare and Mercuri criteria.

RESULTS

Patients with AMA-M2-positive IIM had significantly higher incidence of MRI involvement with fatty infiltration in five lower extremity muscles, namely the adductor magnus (AM) (13/14 VS 14/37, p < 0.001), semimembranosus (SM) (13/14 VS 17/37, p = 0.002), biceps femoris (BF) (12/14 VS 15/37, p = 0.004), soleus (13/14 VS 23/37, p = 0.041), and the medial head of the gastrocnemius (Gastroc M) (13/14 VS 17/37, p = 0.002) than patients with AMA-M2-negative IIM. Furthermore, the severity scores of fatty infiltrations of the above five muscles in AMA-M2-positive IIM were significantly higher than those in patients with AMA-M2-negative IIM (p < 0.001).

CONCLUSIONS

Severe fatty infiltrations of the AM, SM, BF, soleus, and Gastroc M in the posterior muscles of the lower extremities are dominant MRI features in our patients with AMA-M2-positive IIM. This unique muscle MRI character may be a helpful indicator in clinical practice for patients with AMA-M2-positive IIM. Key Points • Striking involvement and prominent fatty infiltrations of five lower extremity muscles (adductor magnus, semimembranosus, biceps femoris, soleus, and the medial head of the gastrocnemius) are interesting MRI performances. • Severe fatty infiltrations in the posterior muscles of the lower extremities are dominant MRI features in AMA-M2-positive IIM. • This unique muscle MRI character may be very helpful for the diagnosis of the AMA-M2-positive IIM.

Sporadic Inclusion Body Myositis at the Crossroads between Muscle Degeneration, Inflammation, and Aging

Sporadic inclusion body myositis (sIBM) is the most common muscle disease of older people and is clinically characterized by slowly progressive asymmetrical muscle weakness, predominantly affecting the quadriceps, deep finger flexors, and foot extensors. At present, there are no enduring treatments for this relentless disease that eventually leads to severe disability and wheelchair dependency. Although sIBM is considered a rare muscle disorder, its prevalence is certainly higher as the disease is often undiagnosed or misdiagnosed. The histopathological phenotype of sIBM muscle biopsy includes muscle fiber degeneration and endomysial lymphocytic infiltrates that mainly consist of cytotoxic CD8+ T cells surrounding nonnecrotic muscle fibers expressing MHCI. Muscle fiber degeneration is characterized by vacuolization and the accumulation of congophilic misfolded multi-protein aggregates, mainly in their non-vacuolated cytoplasm. Many players have been identified in sIBM pathogenesis, including environmental factors, autoimmunity, abnormalities of protein transcription and processing, the accumulation of several toxic proteins, the impairment of autophagy and the ubiquitin-proteasome system, oxidative and nitrative stress, endoplasmic reticulum stress, myonuclear degeneration, and mitochondrial dysfunction. Aging has also been proposed as a contributor to the disease. However, the interplay between these processes and the primary event that leads to the coexistence of autoimmune and degenerative changes is still under debate. Here, we outline our current understanding of disease pathogenesis, focusing on degenerative mechanisms, and discuss the possible involvement of aging.

Extracellular Vesicles in the Pathogenesis, Clinical Characterization, and Management of Dermatomyositis: A Narrative Review

Extracellular vesicles (EVs) are lipid-bilayer particles secreted from cells that primarily assist in cell-to-cell communication through the content of their cargo, such as proteins and RNA. EVs have been implicated in the pathogenesis of various autoimmune diseases, including dermatomyositis (DM), an inflammatory autoimmune disease characterized by distinct cutaneous manifestations, myopathy, and lung disease. We sought to review the role of EVs in DM and understand how they contribute to the pathogenesis and clinical characterization of the disease. We summarized the research progress on EVs in dermatomyositis based on recent publications. EV cargoes, such as double-stranded DNA, microRNA, and proteins, contribute to DM pathogenesis and mediate the proinflammatory response and cytokine release through signaling pathways such as the stimulator of interferon genes (STING) pathway. These nucleic acids and proteins have been proposed as disease-specific, stable biomarkers to monitor disease activity and responses to therapy. They also correlate with clinical parameters, inflammatory markers, and disease severity scores. Furthermore, some markers show an association with morbidities of DM, such as muscle weakness and interstitial lung disease. The continued study of EVs will help us to further elucidate our understanding of dermatomyositis.

[Advances in the diagnostics and treatment of juvenile dermatomyositis]

Juvenile dermatomyositis (JDM) is by far the most frequent inflammatory myopathy in childhood and adolescence. It is clinically characterized by inflammatory changes of the skin and muscles but as a multisystemic disease can also affect the skeletal system, the gastrointestinal tract, lungs and heart. Intrinsic (multigenetic risk) and extrinsic factors (triggers) are involved in the pathogenesis resulting in endothelial damage, involvement of fascies, activation of the interferon system and autoimmune reactions including formation of myositis-specific autoantibodies (MSA). In contrast to dermatomyositis in adults, in children and adolescents there are no associations with malignant diseases. The variable expression, the rarity of the disease and the risk of long-term damage and complications necessitate pediatric rheumatological experience in the diagnostics and treatment. Recently, new approaches in drug treatment have substantially improved the outcome and prognosis but a multidisciplinary treatment (including physicians, physiotherapists, psychologists, social workers) is mandatory, especially in the first phases of the disease. Particularly important is a professionally correct treatment of the functional sequelae, which are a particular focus of this article.

Xist ribonucleoproteins promote female sex-biased autoimmunity

Autoimmune diseases disproportionately affect females more than males. The XX sex chromosome complement is strongly associated with susceptibility to autoimmunity. Xist long non-coding RNA (lncRNA) is expressed only in females to randomly inactivate one of the two X chromosomes to achieve gene dosage compensation. Here, we show that the Xist ribonucleoprotein (RNP) complex comprising numerous autoantigenic components is an important driver of sex-biased autoimmunity. Inducible transgenic expression of a non-silencing form of Xist in male mice introduced Xist RNP complexes and sufficed to produce autoantibodies. Male SJL/J mice expressing transgenic Xist developed more severe multi-organ pathology in a pristane-induced lupus model than wild-type males. Xist expression in males reprogrammed T and B cell populations and chromatin states to more resemble wild-type females. Human patients with autoimmune diseases displayed significant autoantibodies to multiple components of XIST RNP. Thus, a sex-specific lncRNA scaffolds ubiquitous RNP components to drive sex-biased immunity.

Analytic and Clinical Validity of Myositis-Specific Antibodies by Line-Blot Immunoassay Is Essential

OBJECTIVES

This study assessed the concordance between line blot (LB) and immunoprecipitation (IP) assays for detecting myositis-specific antibodies (MSAs) in idiopathic inflammatory myopathies (IIMs) and their association with IIM subtypes.

METHODS

One hundred patients with IIM were enrolled, and MSA was detected using LB and IP. The IIM subtypes, including immune-mediated necrotizing myopathy-like, anti-tRNA synthetase syndrome-like, and clinically amyopathic dermatomyositis-like, were clinically diagnosed. The validity and reliability of the LB compared with the IP were evaluated. Optimal cutoff levels for LB were determined using various statistical methods including Cohen κ, Gwet's AC, diagnostic odds ratios, and receiver operating characteristic analysis.

RESULTS

Line blot exhibited lower specificity and accuracy than IP in predicting IIM subtypes. Some MSAs performed better at higher LB cutoff values. Anti-signal recognition particle antibodies showed poor performance in predicting the immune-mediated necrotizing myopathy-like subtype using LB. Raising the cutoffs improved the reliability of anti-threonyl-tRNA synthetase and anti-signal recognition particle antibodies. Anti-histidyl-tRNA synthetase antibodies performed well at lower positivity, whereas diagnostic odds ratios increased for anti-transcription intermediary factor 1γ and anti-nuclear matrix protein 2 with higher cutoffs.

CONCLUSIONS

Inconsistencies between LB and IP have been observed in patients with IIM. Individual optimal cutoffs for MSA by LB correlating with IP were determined. Rheumatologists should consider the differences between LB and IP results when classifying IIM subtypes.

Research progress on the dermatomyositis specific autoantibodies and malignancy associated dermatomyositis

Dermatomyositis (DM) is an autoimmune disease often complicated with malignant tumors. More than 50% of DM patients have myositis specific autoantibodies in their bodies. DM specific autoantibodies [including anti-migration inhibitory factor (Mi)-2 antibody, anti-nuclear matrix protein (NXP)-2 antibody, anti-transcription intermediary factor (TIF) 1-γ antibody, and anti-small ubiquitin like modifier activating enzyme (SAE) antibody] play important roles in the pathogenesis of malignancy associated DM. Revealing the role of DM specific autoantibodies in the development of malignant tumors in DM patients can provide important evidence for accurately assessing the risk of developing malignant tumors in DM patients, and also provide new ideas for clinical diagnosis of DM and precise treatment.

Clinical risk factors in patients with interstitial lung disease associated with anti-MDA5 autoantibodies

INTRODUCTION

The anti-MDA5-associated autoimmune disease represents a poorly understood entity. The study's objectives were to describe a cohort of interstitial lung disease (ILD) patients who were positive for anti-MDA5 autoantibody and identify clinical risk factors associated with survival.

METHODS

This single-center cohort study included ILD patients positive for anti-MDA5 autoantibody. Baseline clinical features were registered, and survival analysis was performed to identify risk factors associated with worse survival.

RESULTS

Fifty-three ILD-MDA5 positive patients were included; twelve died during follow-up due to rapidly progressive interstitial lung disease (RP-ILD). Dermatological signs of anti-MDA5 (Gottron papules, Gottron sign, palmar papules, V-neck sign, facial dermatomyositis rashes, and skin ulcers) were strongly associated with death secondary to RP-ILD (HR: 3.7, 95% CI: 1.02-13.35). Patients with dermatological signs were younger, had higher anti-MDA5 autoantibodies titers, more frequent inflammatory patterns in HRCT evaluation, and less fibrosis extent in HRCT.

CONCLUSION

Dermatological manifestation in ILD patients to anti-MDA5 autoantibodies are associated with RP-ILD and short-term fatal outcomes. Dermatological signs may identify a subgroup of ILD-positive to anti-MDA5 patients with a high risk of RP-ILD.

[Significance of anti-Jo-1 antibody's clinical stratification in idiopathic inflammatory myopathy and disease spectrum]

OBJECTIVE

To investigate the significance of anti-histidyl tRNA synthetase (Jo-1) antibody in idiopathic inflammatory myopathies (IIM) and its diseases spectrum.

METHODS

We enrolled all the patients who were tested positive for anti-Jo-1 antibody by immunoblotting in Peking University People's Hospital between 2016 and 2022. And the patients diagnosed with anti-synthetase antibody syndrome (ASS) with negative serum anti-Jo-1 antibody were enrolled as controls. We analyzed the basic information, clinical characteristics, and various inflammatory and immunological indicators of the patients at the onset of illness.

RESULTS

A total of 165 patients with positive anti-Jo-1 antibody were enrolled in this study. Among them, 80.5% were diagnosed with connective tissue disease. And 57.6% (95/165) were diagnosed with IIM, including ASS (84/165, 50.9%), immune-mediated necrotizing myopathy (7/165, 4.2%) and dermatomyositis (4/165, 2.4%). There were 23.0% (38/165) diagnosed with other connective tissue disease, mainly including rheumatoid arthritis (11/165, 6.7%), undifferentiated connective tissue disease (5/165, 3.0%), interstitial pneumonia with autoimmune features (5/165, 3.0%), undifferentiated arthritis (4/165, 2.4%), Sjögren's syndrome (3/165, 1.8%), systemic lupus erythematosus (3/165, 1.8%), systemic vasculitis (3/165, 1.8%), and so on. Other cases included 3 (1.8%) malignant tumor patients, 4 (2.4%) infectious cases and so on. The diagnoses were not clear in 9.1% (15 /165) of the cohort. In the analysis of ASS subgroups, the group with positive serum anti-Jo-1 antibody had a younger age of onset than those with negative serum anti-Jo-1 antibody (49.9 years vs. 55.0 years, P=0.026). Clinical manifestations of arthritis (60.7% vs. 33.3%, P=0.002) and myalgia (47.1% vs. 22.2%, P=0.004) were more common in the ASS patients with positive anti-Jo-1 antibody. With the increase of anti-Jo-1 antibody titer, the incidence of the manifestations of arthritis, mechanic hands, Gottron sign and Raynaud phenomenon increased, and the proportion of abnormal creatine kinase and α-hydroxybutyric dehydrogenase index increased in the ASS patients. The incidence of myalgia and myasthenia were significantly more common in this cohort when anti-Jo-1 antibody-positive ASS patients were positive for one and more myositis specific antibodies/myositis associated autoantibodies (P < 0.05).

CONCLUSION

The disease spectrum in patients with positive serum anti-Jo-1 antibody includes a variety of diseases, mainly ASS. And anti-Jo-1 antibody can also be found in many connective tissue diseases, malignant tumor, infection and so on.

A Case Report of Anti-TIF1-γAntibody-Positive Dermatomyositis Concomitant with Small Cell Neuroendocrine Carcinoma of the Urinary Bladder

Small cell neuroendocrine carcinoma is rare among urinary bladder cancer types, and to date, there are no case reports of concurrent antitranscriptional intermediary factor 1-γantibody-positive dermatomyositis. We describe the case of a 69-year-old Japanese man who presented with elevated creatine kinase levels and haematuria on medical examination. Approximately one month later, he developed dysphagia. Laryngoscopy confirmed laryngeal dysfunction. He also presented with muscle weakness and a skin rash. Magnetic resonance imaging of the upper extremities suggested bilateral brachial muscle myositis. He was diagnosed as having dermatomyositis and was later found to be positive for antitranscriptional intermediary factor 1-γ antibody. Computed tomography revealed an intravesical space-occupying lesion and right iliac lymphadenopathy, suggesting urinary bladder cancer. The patient was admitted to our hospital for treatment. Urinary bladder biopsy confirmed small cell neuroendocrine carcinoma because tumour cells were positive for synaptophysin, CD56, and chromogranin A. Thus, the patient was diagnosed as having an antitranscriptional intermediary factor 1-γantibody-positive dermatomyositis concomitant with urinary bladder small cell neuroendocrine carcinoma. The patient was treated with glucocorticoid and intravenous immune globulin therapy for dermatomyositis. Radiotherapy was selected for the carcinoma. Although muscle weakness and skin symptoms improved with treatment, dysphagia persisted. Furthermore, expression of the transcriptional intermediary factor 1-γ protein in tumour cells was also confirmed by immunohistochemistry, but the significance is unknown. It should be noted that antitranscriptional intermediary factor 1-γantibody-positive dermatomyositis can occur concomitantly with such a rare malignancy.

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.

Increased serum soluble interleukin-2 receptor levels in dermatomyositis are associated with Th17/Treg immune imbalance

Dermatomyositis (DM) represents a multifaceted chronic inflammatory myopathy, primarily manifesting as progressive deterioration of muscular and cutaneous tissues. Despite an incomplete comprehension of DM's etiology and pathogenesis, current evidence implicates the involvement of T lymphocyte infiltration, extensive cytokine release, myositis-specific antibodies, and myositis-associated antibodies in disease development. Serum soluble interleukin-2 receptor (sIL-2R) frequently serves as a marker for T cell activation; however, its role remains elusive. Consequently, this investigation sought to elucidate the association between sIL-2R levels, peripheral blood lymphocyte subset counts, and related cytokines in DM patients, with the aim of uncovering the intricate mechanisms underlying DM and establishing a theoretical foundation for the implementation of precise, targeted, individualized immunomodulatory therapy. In this study, a cohort of 60 dermatomyositis (DM) patients, comprising 32 with inactive DM and 28 with active DM, was enrolled and stratified into inactive and active groups based on the Myositis Disease Activity Visual Analogue Scale (MYOACT). Flow cytometry was employed to quantify the absolute counts of peripheral lymphocyte subsets and CD4+T cell subsets in each group, while a flow cytometry bead array was utilized to measure serum cytokine levels. In a comparative analysis between healthy individuals and patients diagnosed with DM, we observed a marked elevation in serum sIL-2R concentrations (P < 0.001) and T-helper 17 cell/regulatory T cell (Th17/Treg) ratios (P < 0.01) within the latter group. A positive correlation was identified between serum sIL-2R levels and various parameters, including ESR, CRP, VAS, AST, CKMB, LDH, HBDH, PT, APTT, DDi, IL-6, IL-10, and IFN-γlevels (P < 0.05). In contrast, serum sIL-2R levels demonstrated a negative correlation with LY, HGB, ALB, Th17 cell populations, and Th17/Treg cell ratios (P < 0.05). Employing multivariate logistic regression, we identified serum sIL-2R concentrations as an independent risk factor for both disease activity and hepatic involvement in DM patients. Moreover, receiver operating characteristic (ROC) curve analyses revealed that serum sIL-2R levels significantly contributed to the differentiation of disease activity and the detection of liver involvement in DM patients, with areas under the ROC curve (AUC) of 0.757 (95% CI 0.630-0.884, P = 0.001) and 0.826 (95% CI 0.717-0.935, P < 0.001), respectively. This study highlights the potential utility of serum sIL-2R levels as a valuable biomarker for assessing disease activity and liver involvement in dermatomyositis. Elevated serum concentrations of sIL-2R were observed in patients with DM, exhibiting significant associations with Th17 cell populations and Th17/ Treg ratios. These findings indicate that sIL-2R may be implicated in the immunopathogenesis of DM, thereby warranting further investigation to elucidate its role in the disease process.

Prevalence of anti-synthetase antibodies among systemic sclerosis patients

BACKGROUND

we aimed to estimate the prevalence of Amino acyl-transfer ribonucleic acid synthetase antibodies (Anti-ARS); myositis specific antibodies, among patients with systemic sclerosis (SSc), to evaluate the clinical associations of anti-ARS antibodies in SSc patients and to identify risk factors for development of interstitial lung disease (ILD) in SSc.

METHODS

A prospective study of 71 systemic sclerosis patients in our rheumatology clinic in Israel. Sera were tested for myositis antibodies. Data on patients clinical and serological manifestations and treatment were collected and compared according to anti-ARS antibodies and ILD.

RESULTS

Prevalence of anti-ARS antibodies was 6% (4/71) with anti PL-7, anti- OJ and Jo-1 positivity. Anti Ro-52 was found in 27%, anti-PM/Scl 75, anti-PM/Scl 100 and anti-SRP in 6%, anti-Ku in 3%, anti-Mi-2 beta and anti-Mi-2 alfa in 4%, anti- NXP2 and anti-TIF1gamma in 1%. ILD complication was observed in 42% of patients and was associated with anti RNAP-III, anti Scl-70 and Anti-ARS antibodies. In multiple logistic regression, anti Scl-70 was associated with 6-fold higher risk for ILD.

CONCLUSION

Anti-ARS antibodies were observed in 6% of SSc patients. All of them had ILD. Due to the low prevalence of anti-ARS, this study could not describe clinical associations of anti-ARS antibodies in SSc patients.

Current Biomarker Strategies in Autoimmune Neuromuscular Diseases

Inflammatory neuromuscular disorders encompass a diverse group of immune-mediated diseases with varying clinical manifestations and treatment responses. The identification of specific biomarkers has the potential to provide valuable insights into disease pathogenesis, aid in accurate diagnosis, predict disease course, and monitor treatment efficacy. However, the rarity and heterogeneity of these disorders pose significant challenges in the identification and implementation of reliable biomarkers. Here, we aim to provide a comprehensive review of biomarkers currently established in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis (MG), and idiopathic inflammatory myopathy (IIM). It highlights the existing biomarkers in these disorders, including diagnostic, prognostic, predictive and monitoring biomarkers, while emphasizing the unmet need for additional specific biomarkers. The limitations and challenges associated with the current biomarkers are discussed, and the potential implications for disease management and personalized treatment strategies are explored. Collectively, biomarkers have the potential to improve the management of inflammatory neuromuscular disorders. However, novel strategies and further research are needed to establish clinically meaningful biomarkers.

[Increasing dyspnoea and intermittent joint suffering]

In rheumatic diseases the possibility of pulmonary manifestation must always be considered and checked. Interstitial lung disease can often be fatal in these cases. In the presented case, the link between progressive dyspnea and newly occurring skin irritation is to be seen as particularly important. A good outcome can be achieved by immediate therapy with immunosuppression and plasmapheresis.

The Autoantibody Array Assay: A Novel Autoantibody Detection Method

Systemic sclerosis (SSc) and dermatomyositis (DM) are autoimmune collagen diseases. Specific autoantibodies are known to be involved in their pathogeneses, each presenting with a different clinical manifestation. Although immunoprecipitation is the gold standard method for detecting autoantibodies, it is difficult to perform in all cases owing to the use of radioisotopes. In this study, we developed a new detection method for SSc and DM autoantibodies (A-cube) using cell-free protein synthesis and examined its validity. Proteins were synthesized using wheat germ cell-free protein synthesis. A total of 100 cases of SSc, 50 cases of DM, and 82 healthy controls were examined. The validity of the method was examined by a comparison with existing test results. Anti-centromere antibody, anti-topoisomerase I antibody, anti-RNA polymerase III antibody, anti-U1RNP anti-body, anti-Jo-1 antibody, anti-TIF1γ antibody, anti-Mi-2 antibody, and anti-ARS antibody were tested for. The results suggested that A-cube is comparable with existing testing methods or has a high sensitivity or specificity. In addition, there was a case in which the diagnosis was reconsidered using the A-cube. The quality of the A-cube was ensured, and its usefulness for a comprehensive analysis was demonstrated. The A-cube can therefore contribute to the clinical assessment and treatment of SSc and DM.

Prediction of progressive pulmonary fibrosis in patients with anti-synthetase syndrome-associated interstitial lung disease

OBJECTIVE

Interstitial lung disease (ILD) is a common extramuscular manifestation of the anti-synthetase syndrome (ASS). Patients with ASS-ILD are at risk in developing a progressive fibrosing phenotype despite appropriate treatments. This study investigated the risk factors and the predictive value of multiple risk factors for progressive pulmonary fibrosis (PPF) in patients with ASS-ILD.

METHODS

Ninety patients with a diagnosis of ASS and evidence of ILD on high-resolution computed tomography (HRCT) were recruited. Among them, 72 participants completed follow-up for more than 12 months. These patients were further divided into a PPF-ASS group (n = 18) and a non-PPF-ASS group (n = 54). Logistic regression analysis was performed to investigate the risk factors for PPF. The predictive value of the combined risk factors for predicting PPF were analyzed by a ROC curve.

RESULTS

The PPF-ASS group had a higher rate of positive non-Jo-1 antibodies, a significantly higher neutrophil-to-lymphocyte ratio (NLR) and serum lactate dehydrogenase (LDH), and a significantly lower PaO2/FiO2 ratio and diffusing capacity for carbon monoxide (DLCO%pred) than the non-PPF-ASS group. In addition, elevated serum Krebs von den Lungen-6 (KL-6) level and reticular opacities were significantly more common, and corticosteroid monotherapy at onset was administered more frequently in the PPF-ASS group. The median duration of follow-up was 37.4 months, survival was poorer in the PPF-ASS group, and the overall survival was 88.9%. Multivariate regression analysis further revealed that positive non-Jo-1 antibodies, NLR, and KL-6 were independent risk factors for PPF. These combined indexes had good accuracy (area under the curve = 0.874) in predicting PPF in patients with ASS-ILD.

CONCLUSION

Positive non-Jo-1 antibodies, NLR, and serum KL-6 are independent risk factors for PPF in patients with ASS-ILD. Monitoring these markers can potentially predict PPF in this group of patients. Key Points • Positive non-Jo-1 antibodies, NLR, and serum KL-6 are independent risk factors associated with PPF in patients with ASS-ILD. • Monitoring non-Jo-1 antibodies, NLR, and serum KL-6 can potentially predict PPF in patients with ASS-ILD.

Increased Otoferlin Expression in B Cells Is Associated with Muscle Weakness in Untreated Juvenile Dermatomyositis: A Pilot Study

Otoferlin mRNA expression is increased in JDM patients' PBMCs and muscle compared to healthy controls. This study aims to evaluate the role of otoferlin in JDM disease pathophysiology and its association with disease activity in untreated children with JDM. A total of 26 untreated JDM (88.5% female, 92.3% white, non-Hispanic) and 15 healthy controls were included in this study. Otoferlin mRNA expression was determined by qRT-PCR before and a few months after therapy. Detailed flow cytometry of various cell surface markers and cytoplasmic otoferlin was performed to identify cells expressing otoferlin. In addition, muscle otoferlin expression was evaluated in situ in six untreated JDM patients and three healthy controls. There was a significant increase in otoferlin expression in JDM children compared to controls (Median 67.5 vs. 2.1; p = 0.001). There was a positive correlation between mRNA otoferlin expression and the following disease activity markers: disease activity scores (DAS)-total (rs = 0.62, p < 0.001); childhood myositis assessment scale (CMAS) (rs = -0.61, p = 0.002); neopterin (rs = 0.57, p = 0.004) and von Willebrand factor antigen (vWF: Ag) (rs = 0.60, p = 0.004). Most of the otoferlin-positive cells were unswitched B cells (63-99.4%), with 65-75% of them expressing plasmablast markers (CD19+, IgM+, CD38hi, CD24-). The findings of this pilot study suggest that otoferlin expression is associated with muscle weakness, making it a possible biomarker of disease activity. Additionally, B cells and plasmablasts were the primary cells expressing otoferlin.

Myositis interstitial lung disease and autoantibodies

The aim of this review is to examine and evaluate published literature associated with idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) based on myositis specific autoantibodies (MSA) and the potential clinical significance of each autoantibody subtype for the practicing clinician. The review is a comprehensive search of literature published in PubMed from the year 2005 and onward coinciding with the surge in the discovery of new MSAs. Additionally, we comment on recommended multidisciplinary longitudinal care practices for patients with IIM-ILD with regard to imaging and other testing. Treatment is not covered in this review.

An Unusual Presentation of Dermatomyositis With Muscle Hypertrophy

Peripheral nerve hyperexcitability is a rare disorder characterized by spontaneous motor unit activity. Although peripheral nerve hyperexcitability is seen in multiple immune-mediated neurological conditions, an association with dermatomyositis has rarely been reported. We present a 65-year-old woman with serological and muscle biopsy features of dermatomyositis who also developed marked muscle hypertrophy, stiffness, and delayed relaxation along with electrodiagnostic features of peripheral nerve hyperexcitability such as that seen in Isaacs syndrome.

The Role of Myositis-Specific and Myositis-Associated Autoantibodies and the Activation of Type I Interferon Pathway in the Generation of Clinical Phenotypes of Inflammatory Myopathies

Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous autoimmune diseases with a prevalence of 20 cases per 100000 of population. Despite their diversity, IMMs are characterised by several common clinical features such as muscle inflammation, proximal muscle weakness, abnormal electromyography and/or muscle biopsy. Over the last years, it has been increasingly recognised that an array of autoantibodies known as myositis-specific antibodies (MSAs) and myositis-associated antibodies (MAAs) are associated with distinct clinical phenotypes and diverse prognosis. Although the exact underlying mechanism of IIMs is not fully understood, accumulating data suggest that the activation of type I interferon pathway plays a central role in disease development. Previous studies have reported the upregulation of type I interferon (IFN) induced genes in peripheral blood and muscle biopsies derived from myositis patients. Given the heterogeneity of inflammatory myopathies along with the central role of type I IFN pathway in disease pathogenesis, the aim of the current study is to elucidate the link between distinct clinical phenotypes of inflammatory myopathies with the presence of serum MSAs or MAAs, as well as with type I IFN activation.

Juvenile idiopathic inflammatory myositis: an update on pathophysiology and clinical care

The childhood-onset or juvenile idiopathic inflammatory myopathies (JIIMs) are a heterogenous group of rare and serious autoimmune diseases of children and young people that predominantly affect the muscles and skin but can also involve other organs, including the lungs, gut, joints, heart and central nervous system. Different myositis-specific autoantibodies have been identified that are associated with different muscle biopsy features, as well as with different clinical characteristics, prognoses and treatment responses. Thus, myositis-specific autoantibodies can be used to subset JIIMs into sub-phenotypes; some of these sub-phenotypes parallel disease seen in adults, whereas others are distinct from adult-onset idiopathic inflammatory myopathies. Although treatments and management have much improved over the past decade, evidence is still lacking for many of the current treatments and few validated prognostic biomarkers are available with which to predict response to treatment, comorbidities (such as calcinosis) or outcome. Emerging data on the pathogenesis of the JIIMs are leading to proposals for new trials and tools for monitoring disease.

Increased expression of cell adhesion molecules in myofasciitis

Background

Myofasciitis is a heterogeneous group of diseases pathologically characterized by inflammatory cell infiltration into the fascia. Endothelial activation plays a critical role in the pathogenesis of the inflammatory response. However, the expression of cellular adhesion molecules (CAMs) in myofasciitis has not been investigated.

Methods

Data on clinical features, thigh magnetic resonance imaging, and muscle pathology were collected from five patients with myofasciitis. Immunohistochemical (IHC) staining and Western blot (WB) of the muscle biopsies from patients and healthy controls were performed.

Results

Increased levels of serum pro-inflammatory cytokines, including IL-6, TNF-α, and IL-2R, were detected in four patients. IHC staining and WB indicated significantly increased expression of cell adhesion molecules in blood vessels or inflammatory cells within the perimysium in muscle and fascia tissues of patients with myofasciitis compared to controls.

Conclusion

The up-regulation of CAMs in myofasciitis indicates endothelial activation, which may be potential therapy targets for the treatment of myofasciitis.

Clinical and laboratory characteristics of idiopathic inflammatory myositis in Saudi patients: A retrospective study in a single tertiary centre

OBJECTIVES

Idiopathic inflammatory myositis (IIM) in Saudi patients has been poorly studied owing to the lack of available data. This study aimed to identify the clinical and laboratory features of patients at a single tertiary care center.

METHODS

This retrospective study reviewed the medical records of Prince Sultan Military Medical City, Riyadh, Saudi Arabia to collect clinical and laboratory data between December 2022 and February 2017 as follows: age at disease onset, gender, follow-up duration and disease duration; clinical symptoms; laboratory result; presence and type of myositis-specific autoantibody or myositis-associated autoantibody; and type of immunosuppression, presence of malignancy, disease course, and outcome.

RESULTS

There were 26 patients with a mean age of 36.16±13.48, and 84.6% were women. The most prevalent form of IIM was dermatomyositis (n=16, 61.5%), and the most affected organ was the skin. weakness was observed in 25 patients (96.2%), and dysphagia was the most common alarm sign (n=10, 38.5%). During follow-up, the creatine kinase level was elevated at the beginning of the disease and then decreased following treatment, with a mean of 277.73 IU/L. Of the total patients, 17 (68%) were positive for anti-nuclear antibody and 5 (19.2%) were positive for anti-Jo-1.

CONCLUSION

In our patients, dermatomyositis was the most common form of myositis, and skin manifestations were the most prevalent clinical characteristics. None of the patients developed a malignancy or died.

Atrophic Gastritis and Autoimmunity: Results from a Prospective, Multicenter Study

Despite a global decrease, gastric cancer (GC) incidence appears to be increasing recently in young, particularly female, patients. The causal mechanism for this "new" type of GC is unknown, but a role for autoimmunity is suggested. A cascade of gastric precancerous lesions, beginning with chronic atrophic gastritis (CAG), precedes GC. To test the possible existence of autoimmunity in patients with CAG, we aimed to analyze the prevalence of several autoantibodies in patients with CAG as compared to control patients. Sera of 355 patients included in our previous prospective, multicenter study were tested for 19 autoantibodies (anti-nuclear antibodies, ANA, anti-parietal cell antibody, APCA, anti-intrinsic factor antibody, AIFA, and 16 myositis-associated antibodies). The results were compared between CAG patients (n = 154), including autoimmune gastritis patients (AIG, n = 45), non-autoimmune gastritis patients (NAIG, n = 109), and control patients (n = 201). ANA positivity was significantly higher in AIG than in NAIG or control patients (46.7%, 29%, and 27%, respectively, p = 0.04). Female gender was positively associated with ANA positivity (OR 0.51 (0.31-0.81), p = 0.005), while age and H. pylori infection status were not. Myositis-associated antibodies were found in 8.9% of AIG, 5.5% of NAIG, and 4.4% of control patients, without significant differences among the groups (p = 0.8). Higher APCA and AIFA positivity was confirmed in AIG, and was not associated with H. pylori infection, age, or gender in the multivariate analysis. ANA antibodies are significantly more prevalent in AIG than in control patients, but the clinical significance of this finding remains to be established. H. pylori infection does not affect autoantibody seropositivity (ANA, APCA, AIFA). The positivity of myositis-associated antibodies is not increased in patients with CAG as compared to control patients. Overall, our results do not support an overrepresentation of common autoantibodies in patients with CAG.

Clinical Outcomes With and Without Plasma Exchange in the Treatment of Rapidly Progressive Interstitial Lung Disease Associated With Idiopathic Inflammatory Myopathy

BACKGROUND/OBJECTIVE

A subset of patients with idiopathic inflammatory myopathy (IIM) develops highly fatal, rapidly progressive interstitial lung disease (RP-ILD). Treatment strategies consist of glucocorticoid and adjunctive immunosuppressive therapies. Plasma exchange (PE) is an alternative therapy, but its benefit is unclear. In this study, we aimed to determine whether PE benefited outcomes for patients with RP-ILD.

METHODS

In this medical records review study, we compared baseline characteristics and clinical outcomes for 2 groups of patients with IIM-related RP-ILD: those who received and did not receive PE.

RESULTS

Our cohort consisted of 15 patients, 9 of whom received PE. Baseline demographic characteristics and severity of lung, skin, and musculoskeletal disease between the 2 groups of patients were not significantly different. Five patients required mechanical ventilation (2, PE; 3, no PE). Plasma exchange was generally a third-line adjunctive treatment option. The PE group had a longer median (interquartile range) hospitalization (27.0 [23.0-36.0] days) than the non-PE group (12.0 [8.0-14.0] days) ( p = 0.02). There was a potential benefit in 30-day mortality improvement in those receiving PE (0% vs 33%, p = 0.14), with a statistically significant improvement in 2 important composite end points including 30-day mortality or need for lung transplant (0% vs 50%, p = 0.04) and 1-year mortality or need for lung transplant or hospital readmission for RP-ILD in those receiving PE (22% vs 83%, p = 0.04).

CONCLUSIONS

Plasma exchange may be an underutilized, safe salvage therapy for patients with IIM-related RP-ILD when other immunosuppressive therapies fail.

Severe rhabdomyolysis due to idiopathic inflammatory myopathies, a wary manifestation of a heterogenous pathology

Idiopathic inflammatory myopathies (IIM) are historically classified by The Bohan and Peter criteria. The presentation of IIM is versatile and clinical-serological findings can aid in diagnosing the underlying form of IIM. Over the past years, the discovery and the use of myositis-specific autoantibodies (MSA) and myositis-associated autoantibodies (MAA) have led to a more heterogeneous classification by the European League Against Rheumatism and American College of Rheumatology (EULAR/ACR).This paper describes a case of dermatomyositis sine dermatitis. A 70-year -old woman presented with complaints of muscle weakness and was admitted because of severe oliguric renal failure due to rhabdomyolysis. Despite treatment with hemodialysis and initial recovery, her clinic worsened again. The disease course in combination with electromyography findings, PET-scan results, and positive myositis-specific autoantibodies, that is, anti-NXP-2 antibodies, ultimately led to the diagnosis.Today, commercial kits based on line immunoassay and dot blot have mostly replaced the labor-intensive immunoprecipitation of RNA and/or proteins for detecting MSA. Though it makes routine testing of multiple MSA easy to implement in clinical practice, more validation studies are required and clinicians should be aware of its limitations, including false-positive results. When clinical suspicion for IIM is high, a negative screening for antinuclear antibodies (ANA) result does not exclude IIM and the first test of choice remains a multi-specific immunoassay for the whole spectrum of MSA.In this paper, we want to underline that there is no shortcut in diagnosing IIM. Caution is required in interpreting different EMG, PET-scan, histological, and laboratory findings. Especially in the case of rhabdomyolysis, as this is a severe and wary manifestation of myositis.

Dermatomyositis: a comprehensive review of clinical manifestations, serological features, and therapeutic approaches

Dermatomyositis (DM) is an autoimmune disorder, which belongs to a group of rare autoimmune dermatoses characterized by different skin features and variable muscle involvement. We recognize four main variants of DM: classic DM, clinically amyopathic DM, paraneoplastic DM, and juvenile DM. Clinically, patients show several skin features, but heliotrope rash, and violaceous papules located at the interphalangeal or metacarpophalangeal joints (Gottron's papules) are the most frequently observed. Together with skin features, patients show muscle involvement, most commonly with symmetrical weakness of the proximal muscles. DM belongs to the facultative paraneoplastic dermatoses and a wide range of solid or hematologic malignancies can be detected in DM patients. Serologically, a wide range of autoantibodies can be detected in patients with DM. Indeed, distinct serotypes can be related to specific phenotypes with specific clinical features, carrying a different risk for systemic involvement and for malignancies. Systemic corticosteroids are still considered the first-line approach, but several steroid-sparing agents, such as methotrexate, azathioprine or mycophenolate mofetil, have been reported as effective in treating DM. Furthermore, new class of drugs, such as monoclonal antibodies, purified immunoglobulins or Janus kinase inhibitors are becoming more relevant in the clinical practice or are currently under investigation. In this work, we aim to offer a clinical overview of the diagnostic workout, the characteristics of DM variants, the role of autoantibodies in DM, and the management of this life-threatening systemic disorder.

Fibromyalgia patients with elevated levels of anti-satellite glia cell immunoglobulin G antibodies present with more severe symptoms

ABSTRACT

Transferring fibromyalgia patient immunoglobulin G (IgG) to mice induces pain-like behaviour, and fibromyalgia IgG binds mouse and human satellite glia cells (SGCs). These findings suggest that autoantibodies could be part of fibromyalgia pathology. However, it is unknown how frequently fibromyalgia patients have anti-SGC antibodies and how anti-SGC antibodies associate with disease severity. Here, we quantified serum or plasma anti-SGC IgG levels in 2 fibromyalgia cohorts from Sweden and Canada using an indirect immunofluorescence murine cell culture assay. Fibromyalgia serum IgG binding to human SGCs in human dorsal root ganglia tissue sections was also assessed by immunofluorescence. In the cell culture assay, anti-SGC IgG levels were increased in both fibromyalgia cohorts compared with control group. Elevated anti-SGC IgG was associated with higher levels of self-reported pain in both cohorts, and higher fibromyalgia impact questionnaire scores and increased pressure sensitivity in the Swedish cohort. Anti-SGC IgG levels were not associated with fibromyalgia duration. Swedish fibromyalgia (FM) patients were clustered into FM-severe and FM-mild groups, and the FM-severe group had elevated anti-SGC IgG compared with the FM-mild group and control group. Anti-SGC IgG levels detected in culture positively correlated with increased binding to human SGCs. Moreover, the FM-severe group had elevated IgG binding to human SGCs compared with the FM-mild and control groups. These results demonstrate that a subset of fibromyalgia patients have elevated levels of anti-SGC antibodies, and the antibodies are associated with more severe fibromyalgia symptoms. Screening fibromyalgia patients for anti-SGC antibodies could provide a path to personalized treatment options that target autoantibodies and autoantibody production.

Analysis of the clinical features of antisynthetase syndrome: a retrospective cohort study in China

OBJECTIVE

To summarize the clinical, serological, and radiological characteristics of anti-synthetase syndrome (ASS) patients with different anti-aminoacyl-tRNA synthase antibody.

METHODS

Retrospective analysis was performed based on the clinical data of 88 patients diagnosed with ASS in Tianjin Medical University General Hospital from January 2015 to December 2020. The clinical data included general conditions, serological indexes, high-resolution CT (HRCT) characteristics, and pulmonary function manifestations.

RESULTS

Among the 88 patients, there were 17 males and 71 females. The anti-synthetase antibodies included anti-Jo-1 (n = 42), anti-PL-7 (n = 14), anti-PL-12 (n = 9), anti-EJ (n = 20), and anti-OJ (n = 3) antibodies. The most common clinical manifestations of ASS patients were interstitial lung disease (ILD) (90%, 79/88), followed by myositis (79.5%, 70/88), arthritis (50%, 44/88), and rash (50%, 44/88). The frequency of arthritis in the anti-Jo-1 antibody-positive group was higher than that of the anti-PL-7 and anti-EJ antibody groups (P = 0.004, P = 0.002, respectively). The frequency of Gottron's sign in the anti-PL-7 antibody positive group was higher than that of the anti-Jo-1 and anti-PL-12 antibody-positive groups (P = 0.006, P = 0.04). Isolated arthritis was the most frequent initial symptoms in anti-Jo-1 antibody-positive group (47.6%, 20/42), while isolated ILD was most frequent in patients with anti-EJ antibody (50%, 10/20), and isolated myositis in patients carrying anti-OJ (66.7%, 2/3). There were only 32 cases (36.4%) with the typical clinical triad (myositis, arthritis, ILD). In our cohort, 79 patients (90%) were complicated with ILD. Meanwhile, 7 out of 79 cases were classified into rapid progressive group with 6 cases (85.7%) carrying anti-Ro-52 antibody. The probability of reticular and honeycombing shadow in HRCT of patients with anti-EJ antibody positive was higher than that of other groups (P < 0.05).

CONCLUSION

ILD, myositis, and arthritis were the most common clinical manifestations in patients with ASS. Different antibody-positive patients have different initial symptoms. Patients with isolated arthritis, myositis, and ILD should be vigilant of ASS. The complication of anti-Ro-52 antibody in ASS patients was associated with rapidly progressive pulmonary interstitial disease. Patients with positive anti-EJ antibodies tend to have ILD as the first symptom, and with high occurrence of ILD, the HRCT showed more serious patterns, suggesting the correlation between anti-EJ antibodies and ILD. Key Points • Analyzing specific clinical manifestations in ASS patients with different ARS antibodies can raise awareness of the disease and reduce misdiagnosis. • Anti-EJ antibodies were correlated with ILD. • Anti-Ro-52 antibodies may correlate with RP-ILD in ASS patients.

Myositis-Specific and Myositis-Associated Antibodies in Fibromyalgia Patients: A Prospective Study

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

COVID-19 Pneumonia Followed by Anti-signal Recognition Particle Antibody-positive Fibrosing Interstitial Lung Disease: A Case Report

Coronavirus disease 2019 (COVID-19) pneumonia is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is frequently accompanied by various sequelae. Interstitial lung diseases (ILDs) are observed in COVID-19 pneumonia patients after recovery, probably due to persistent inflammation in the lungs. We herein report a case of ILD with anti-signal recognition particle antibodies following severe COVID-19 pneumonia. The patient was diagnosed with ILD three months after COVID-19 pneumonia. Although the exact mechanism is unknown, the autoantibody-induced immune response might have been the pulmonary fibrosis trigger in this patient.

Human epididymis protein 4 as a clinical biomarker in identifying interstitial lung disease in patients with idiopathic inflammatory myopathies

OBJECTIVE

Human epididymis protein 4 (HE4) can differentiate interstitial lung disease from patients with some rheumatic diseases. However, the clinical utility of HE4 in idiopathic inflammatory myopathies (IIM) remains unclear.

METHODS

80 IIM patients and 91 age and gender-matched healthy controls (HCs) were recruited. Clinical and laboratory data were recorded at baseline and 12 weeks. HE4 was tested by the method of electrochemical luminescence.

RESULTS

Compared to HCs, the levels of HE4 significantly elevated in IIM patients. Patients with elevated HE4 had a higher interstitial lung disease (ILD) prevalence. Among patients with ILD, histological patterns of organizing pneumonia had higher HE4 levels than non-specific interstitial pneumonia. Further, there was a positive correlation between HE4 and the semi-quantitative CT grade (r = 0.778, p < 0.001) and a negative relation between HE4 and the percentage of forced vital capacity (p < 0.001) and diffusing capacity of the lung for carbon monoxide (DLco) (p = 0.001). An optimal cut-off value of HE4 (79.6 pmol/L) for distinguishing IIM-ILD was analyzed by ROC analysis with an AUC of 0.733 (p = 0.002). Regression analysis revealed that elevated HE4 independently identified IIM-related ILD (OR 34.8, 95 %CI, 3.58-338.14, p = 0.002). With the improvement after treatment, serum HE4 levels were significantly decreased (p = 0.006), accompanied by improved DLco% (p = 0.012).

CONCLUSIONS

Serum HE4 was significantly elevated in patients with IIM and may be utilized as a serum biomarker to evaluate the disease severity and prognosis of IIM-related ILD.

Antisynthetase Syndrome in a Patient with Pulmonary Embolism and Nonbacterial Thrombotic Endocarditis

Antisynthetase syndrome is a rare autoimmune disease within the subset of idiopathic inflammatory myopathies. The diagnostic criteria include the presence of an aminoacyl-tRNA synthetase antibody, and typical clinical findings, including myositis, mechanic's hands, Raynaud phenomenon, unexplained fever, and interstitial lung disease. We describe a case of a 59-year-old male who presented with a 1-month history of progressive purplish discoloration and pain of the fingertips, dyspnea, cough, weight loss, fatigue, and who developed progressive proximal muscle weakness and dysphagia. Investigations revealed pulmonic valve and mitral valve marantic endocarditis, pulmonary embolism, myositis, organizing pneumonia, and elevation of anti-OJ antibodies. He was diagnosed with antisynthetase syndrome and treated with high dose corticosteroids and mycophenolate mofetil with a fair response.

Diagnosing lung involvement in inflammatory rheumatic diseases-Where do we currently stand?

Lung involvement is the most common and serious organ manifestation in patients with inflammatory rheumatic disease (IRD). The type of pulmonary involvement can differ, but the most frequent is interstitial lung disease (ILD). The clinical manifestations of IRD-ILD and severity can vary from subclinical abnormality to dyspnea, respiratory failure, and death. Consequently, early detection is of significant importance. Pulmonary function test (PFT) including diffusing capacity of the lungs for carbon monoxide (DLCO), and forced vital capacity (FVC) as well as high-resolution computed tomography (HRCT) are the standard tools for screening and monitoring of ILD in IRD-patients. Especially, the diagnostic accuracy of HRCT is considered to be high. Magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) allow both morphological and functional assessment of the lungs. In addition, biomarkers (e.g., KL-6, CCL2, or MUC5B) are being currently evaluated for the detection and prognostic assessment of ILD. Despite the accuracy of HRCT, invasive diagnostic methods such as bronchoalveolar lavage (BAL) and lung biopsy are still important in clinical practice. However, their therapeutic and prognostic relevance remains unclear. The aim of this review is to give an overview of the individual methods and to present their respective advantages and disadvantages in detecting and monitoring ILD in IRD-patients in the clinical routine.

Endothelin-1 as a Biomarker of Idiopathic Pulmonary Fibrosis and Interstitial Lung Disease Associated with Autoimmune Diseases

The aim of this study was to determine the role of endothelin-1 (ET-1), a molecule involved in multiple vascular and fibrosing abnormalities, as a biomarker of interstitial lung disease (ILD), as well as its use for the differential diagnosis between idiopathic pulmonary fibrosis (IPF) and ILD associated with autoimmune diseases (AD-ILD), using a large and well-defined cohort of patients with ILD. A total of 112 patients with IPF, 91 patients with AD-ILD (28 rheumatoid arthritis (RA), 26 systemic sclerosis, 20 idiopathic inflammatory myositis and 17 interstitial pneumonia with autoimmune features) and 44 healthy controls were included. ET-1 serum levels were determined by enzyme-linked immunosorbent assay. A significant increase in ET-1 levels was found in patients with IPF compared to controls. Likewise, AD-ILD patients also showed higher ET-1 levels than controls when the whole cohort was stratified by the type of AD. Similar ET-1 levels were found in IPF and AD-ILD patients, regardless of the underlying AD. Interestingly, increased ET-1 levels were correlated with worse lung function in IPF and RA-ILD patients. Our study supports that serum ET-1 may be useful as a biomarker of ILD, although it could not help in the differential diagnosis between IPF and AD-ILD. Moreover, ET-1 levels may be associated with ILD severity.