Myositis-associated Autoantibodies Research Articles

Myositis Autoantibody Profiles and Clinical Significance in Patients with Inflammatory Myopathies in Southwest China.

The purpose of this study is to analyze the distribution of myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) in patients with idiopathic inflammatory myopathies (IIMs) in southwest China and to explore the relevance between each subtype, each clinical feature, and to explore the relevance between the laboratory indexes. For this study, 200 patients with IIMs were tested for myositis autoantibodies. Clinical manifestations and laboratory metrics were collected and the correlations between autoantibodies and clinical phenotypes were analyzed. MSAs were found in 73.5% of the patients. The most frequently MSAs were anti-MDA5 (26.8%), followed by anti-ARS (18.5%). Anti-Ro52 was the most prevalent in MAAs (46.2%). Interstitial lung disease (ILD) and arthralgia were more frequent in anti-MDA5 and anti-Jo-1 positive groups (each p < 0.05). Anti-TIF1-γ and anti-NXP2 were associated with dysphagia (each p < 0.05). Different antibody subtypes were associated with laboratory indicators of response to muscle damage and immune status. Logistic regression showed that anti-MDA5 and anti-Jo-1 were independent risk factors for ILD (OR = 4.542, p = 0.004; OR = 4.290, p = 0.018, respectively) and arthralgia (OR = 7.856, p = 0.000; OR = 5.731, p = 0.004, respectively), whereas anti-TIF1-γ and anti-NXP2 were independent risk factors for dysphagia (OR = 4.521, p = 0.009; OR = 6.889, p = 0.017, respectively). Different antibody subtypes were associated with specific clinical features. Anti-MDA5 and anti-Jo-1 were independent risk factors for ILD and arthralgia. Anti-TIF1-γ and anti-NXP2 were independent risk factors for dysphagia.

Myositis-specific and Myositis-associated Autoantibodies in Saudi Patients

Myositis-specific and Myositis-associated Autoantibodies in Saudi Patients

Myositis-associated interstitial lung disease

Introduction/ObjectiveTo review the epidemiology, general clinical aspects and diagnosis, impact on morbidity and mortality, and general treatment approaches for myositis-associated ILD. Materials and methodsThe relevant literature was reviewed. ResultsThe clinical, radiographic, and histopathological features of interstitial lung disease (ILD) in idiopathic inflammatory myopathies (IIM) are similar to idiopathic ILD. Patients with a known diagnosis of myositis require prompt clinical evaluation including the determination of myositis-associated autoantibodies. Patients possessing autoantibodies associated with ILD or those with any pulmonary symptoms should undergo a pulmonary function test and high-resolution CT (HRCT) scanning of their lungs. ConclusionDespite the lack of placebo-controlled trials, systemic glucocorticoids are considered the mainstay of initial treatment of myositis-associated ILD. Glucocorticoid-sparing agents are often concomitantly administered, particularly in patients with severe disease. The first-line conventional immunosuppressive drugs include either mycophenolate mofetil or azathioprine. If these agents fail or if the pulmonary features are severe or rapidly progressive, then more aggressive immunosuppressive or immunomodulatory therapy including cyclophosphamide, tacrolimus or cyclosporine, rituximab, IVIg, or tofacitinib can be considered. Further investigations are required to assess the role of novel therapies in the treatment of myositis-associated ILD.

Myositis-Associated Autoantibodies in Patients With Juvenile Myositis Are Associated With Refractory Disease and Mortality.

Myositis-associated autoantibodies (MAAs) have been associated with overlap myositis, certain disease manifestations such as interstitial lung disease (ILD), and worse prognosis in the idiopathic inflammatory myopathies. MAAs overall remain largely uncharacterized in patients with juvenile-onset myositis. Moreover, it is unknown whether the number of MAAs is associated with disease severity. Patients with juvenile myositis in cross-sectional natural history studies who underwent testing for myositis autoantibodies were included. Demographics, myositis autoantibodies, clinical characteristics, medications received, and outcomes of those with and without MAAs were compared. Multivariable logistic regression was performed to determine whether the number of MAAs detected was associated with severe disease features. Among 551 patients, 36% had an MAA and 13% had more than one MAA. Among those who were MAA positive, there was a higher frequency of overlap myositis (18% vs 5.9%, P < 0.001). MAA positivity was associated with certain clinical features, including Raynaud phenomenon (odds ratio [OR] 2.44, 95% confidence interval [CI] 1.41-4.28) and ILD (OR 3.43, 95% CI 1.75-6.96), as well as a chronic disease course (OR 1.72, 95% CI 1.10-2.72) and mortality (OR 3.76, 95% CI 1.72-8.43). The number of MAAs was also associated with mortality (OR 1.83, 95% CI 1.16-2.86). MAAs were prevalent in a large cohort of patients with juvenile myositis. ILD, refractory disease, and mortality were associated with MAA positivity. Prospective studies are needed to determine whether early detection of MAAs may lead to improved outcomes for patients with juvenile myositis.

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.

Myositis-associated interstitial lung disease

Introduction/ObjectiveTo review the epidemiology, general clinical aspects and diagnosis, impact on morbidity and mortality, and general treatment approaches for myositis-associated ILD. Materials and methodsThe relevant literature was reviewed. ResultsThe clinical, radiographic, and histopathological features of interstitial lung disease (ILD) in idiopathic inflammatory myopathies (IIM) are similar to idiopathic ILD. Patients with a known diagnosis of myositis require prompt clinical evaluation including the determination of myositis-associated autoantibodies. Patients possessing autoantibodies associated with ILD or those with any pulmonary symptoms should undergo a pulmonary function test and high-resolution CT (HRCT) scanning of their lungs. ConclusionDespite the lack of placebo-controlled trials, systemic glucocorticoids are considered the mainstay of initial treatment of myositis-associated ILD. Glucocorticoid-sparing agents are often concomitantly administered, particularly in patients with severe disease. The first-line conventional immunosuppressive drugs include either mycophenolate mofetil or azathioprine. If these agents fail or if the pulmonary features are severe or rapidly progressive, then more aggressive immunosuppressive or immunomodulatory therapy including cyclophosphamide, tacrolimus or cyclosporine, rituximab, IVIg, or tofacitinib can be considered. Further investigations are required to assess the role of novel therapies in the treatment of myositis-associated ILD.

Detection of Myositis Autoantibodies by Multi-Analytic Immunoassays in a Large Multicenter Cohort of Patients with Definite Idiopathic Inflammatory Myopathies.

The usefulness of myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) for the assessment of idiopathic inflammatory myopathies (IIMs) is acknowledged, but laboratory standardization remains a challenge. We detected MSAs/MAAs by multi-analytic line immunoassay (LIA) and particle-based multi-analyte technology (PMAT) in a multicenter cohort of patients with IIMs. We tested the sera from 411 patients affected with definite IIM, including 142 polymyositis (PM), 147 dermatomyositis (DM), 19 cancer-associated myositis, and 103 overlap myositis syndrome (OM), and from 269 controls. MSAs/MAAs were determined by 16Ags LIA in all sera, and anti-HMGCR by ELISA in 157/411 IIM sera and 91/269 control sera. The analytical specificity of LIA/HMGCR ELISA was compared with that of PMAT in 89 MSA+ IIM sera. MSAs/MAAs were positive in 307/411 (75%) IIM patients and 65/269 (24%) controls by LIA (Odds Ratio 9.26, 95% CI 6.43-13.13, p < 0.0001). The sensitivity/specificity of individual MSAs/MAAs were: 20%/100% (Jo-1), 3%/99.3% (PL-7), 4%/98.8% (PL-12), 1%/100% (EJ), 0.7%/100% (OJ), 9%/98% (SRP), 5.6%/99.6% (TIF1γ), 4.6%/99.6% (MDA5), 8%/96% (Mi-2), 1.5%/98% (NXP2), 1.7%/100% (SAE1), 4%/92% (Ku), 8.5%/99% (PM/Scl-100), 8%/96% (PM/Scl-75), and 25.5%/79% (Ro52). Anti-HMGCR was found in 8/157 (5%) IIM patients and 0/176 (0%) controls by ELISA (p = 0.007). Concordance between LIA/HMGCR ELISA and PMAT was found in 78/89 (88%) samples. Individual MSAs detected by LIA were associated with IIM subsets: Jo-1 with PM and OM, PL-12 with OM, Mi-2, TIF1γ, and MDA5 with DM, SRP with PM, and PM/Scl-75/100 with OM (p < 0.001 for all). Since MSAs are mostly mutually exclusive, multi-specific antibody profiling seems effective for a targeted clinical-serologic approach to the diagnosis of IIMs.

Anti-SRP antibody-associated necrotizing myopathy: 2 clinical cases

Necrotizing myopathies are a subtype of autoimmune myopathies characterized by muscle fiber necrosis with minimal infiltration by inflammatory cells on muscle biopsy. This group of myopathies is defined by flaccid palsies due to prima‑ ry skeletal muscle damage as well as extramuscular manifestations such as fever, rash, arthritis, Raynaud’s syndrome and interstitial lung disease. The presence of anti-SRP antibodies is associated with rapidly progressive refractory myositis predominantly affecting limb muscles and axial muscles.Objective of the work is to analyze the course of severe, refractory to several lines of immunosuppressive therapies anti-SRP associated necrotizing myopathy and to highlight an adequate treatment regime.Necrotizing myopathy was suspected in patients aged 39 and 56 years with rapidly progressive flaccid tetraparesis on the basis of clinical and anamnestic data, the results of needle electromyography and muscle magnetic resonance imaging, as well as the analysis of myositis-specific and myositis-associated autoantibodies. In both cases, a rapid development of atrophies, marked muscle weakness in the limbs, without involvement of the bulbar musculature, was observed. To achieve effective control of the disease progression, several lines of therapy were required: glucocorticosteroids, intravenous immunoglobulins, methotrexate and rituximab. Our observations are consistent with those in the literature.Our observations illustrate the clinical course of severe myopathy associated with anti-SRP antibodies. Early initiation of aggressive immunosuppression is crucial to control the disease progression. Treatment and rehabilitation allow achieving significant improvement of the patient’s condition.

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.

Myositis-related autoantibody profile and clinical characteristics stratified by anti-cytosolic 5'-nucleotidase 1A status in connective tissue diseases.

Cytosolic 5'-nucleotidase 1A (cN-1A) autoantibodies have been recognized as myositis-related autoantibodies. However, their correlations with clinical characteristics and other myositis-specific and myositis-associated autoantibodies (MSAs/MAAs) are still unclear. We aimed to establish the prevalence and clinical and laboratory associations of cN-1A autoantibodies in a cohort of patients with connective tissue diseases. A total of 567 participants (182 idiopathic inflammatory myopathies [IIM], 164 systemic lupus erythematosus [SLE], 121 systemic sclerosis [SSc], and 100 blood donors [BD]) were tested for the presence of cN-1A autoantibodies and other myositis-specific and myositis-associated autoantibodies (MSAs/MAAs). Clinical and laboratory characteristics were compared between anti-cN-1A positive and negative patients with sporadic inclusion body myositis (sIBM) and between anti-cN-1A positive and negative patients with non-IBM IIM. In the sIBM cohort, 30 patients (46.9%) were anti-cN-1A positive vs. 18 (15.2%) in the non-IBM IIM cohort, 17 (10%) were anti-cN-1A positive in the SLE cohort and none in the SSc or the BD cohorts. Anti-cN-1A positivity had an overall sensitivity of 46.9% and a specificity of 93.2% for sIBM. Dysphagia was more frequent in the anti-cN-1A positive vs. negative sIBM patients (p = .04). In the non-IBM IIM group, being anti-cN-1A antibody positive was associated with the diagnosis polymyositis (p = .04) and overlap-myositis (p = .04) and less disease damage evaluated by physician global damage score (p < .001). cN-1A autoantibodies were predominantly found in IIM patients and was associated with dysphagia in sIBM patients. Notably, anti-cN-1A appears to identify a distinct phenotype of anti-cN-1A positive non-IBM IIM patients with a milder disease course.

Association of anti-TPM4 autoantibodies with vasculopathic cutaneous manifestations in juvenile dermatomyositis.

AECAs are detected in multiple forms of vasculitis or vasculopathy, including JDM. High levels of tropomyosin alpha-4 chain (TPM4) gene expression in cutaneous lesions and TPM4 protein expression in some endothelial cells (ECs) have been proven. Furthermore, the presence of autoantibodies to tropomyosin proteins have been discovered in DM. We therefore investigated whether anti-TPM4 autoantibodies are an AECA in JDM and are correlated with clinical features of JDM. The expression of TPM4 protein in cultured normal human dermal microvascular ECs was investigated by Western blotting. Plasma samples from 63 children with JDM, 50 children with polyarticular JIA (pJIA) and 40 healthy children (HC) were tested for the presence of anti-TPM4 autoantibodies using an ELISA. Clinical features were compared between JDM patients with and without anti-TPM4 autoantibodies. Autoantibodies to TPM4 were detected in the plasma of 30% of JDM, 2% of pJIA (P < 0.0001) and 0% of HC (P < 0.0001). In JDM, anti-TPM4 autoantibodies were associated with the presence of cutaneous ulcers (53%; P = 0.02), shawl sign rash (47%; P = 0.03), mucous membrane lesions (84%; P = 0.04) and subcutaneous edema (42%; P < 0.05). Anti-TPM4 autoantibodies significantly correlated with the use of intravenous steroids and IVIG therapy in JDM (both P = 0.01). The total number of medications received was higher in patients with anti-TPM4 autoantibodies (P = 0.02). Anti-TPM4 autoantibodies are detected frequently in children with JDM and are novel myositis-associated autoantibodies. Their presence correlates with vasculopathic and other cutaneous manifestations of JDM that may be indicative of more refractory disease.

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

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. 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. 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. 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.

Seroprevalence of SARS-CoV-2 in treatment naïve patients of rheumatological diseases

Dear Sir,COVID-19 is of paramount concern in the rheumatology community. As per current consensus, patients of rheumatological diseases (RDs) are at higher risk of SARS-CoV-2 infection than the general population (high agreement but very low grade of evidence); however, contradictory reports are available regarding its seroprevalence and association with severity and mortality. However, these inferences are mainly based on patients who have long-standing RDs and on various therapies. Then what would happen to those who are treatment-naive, mildly symptomatic, or carrying this disease unknowingly in the community during this pandemic? To explore this aspect, we screened blood samples of clinically suspected patients of autoimmune diseases (ADs) for COVID-19 IgG antibody during the pandemic in the pre-vaccination period. Based on clinical profile, antinuclear antibody (ANA), antineutrophilic cytoplasmic antibody (ANCA), and myositis-associated autoantibodies were tested. Out of 268 clinically suspected cases of RDs, 131 samples were positive for autoantibodies: RD group (114 ANA+08 myositis associated antibody+09 ANCA), and the rest 137 were negative (non-RD group). Out of these, three samples each from RD (3/131; 2.29%) and non-RD group (3/137; 2.17%) turned out to be positive for COVID-19 IgG antibody (EUROIMMUN, Germany), suggesting no increased prevalence of COVID19 in patients of the RD group (OR=1.046, 95% CI: 0.145–7.53, P=0.9645). Among the RD group, two patients were finally diagnosed with systemic lupus erythematosus (SLE); however, others did not turn up again to the hospital to comment on the final diagnosis. None of these COVID-19 positive patients had any known comorbidities or RD-related treatment. These positive patients from both groups had almost similar mildto-moderate COVID-19 disease courses with a favorable outcome. A meta-analysis found a marginal association of ADs with increased risk of severity and mortality of COVID-19 disease (Risk of severity: OR=1.21, 95% CI: 0.58–2.5, P=0.79; Risk of mortality: OR=1.31, 95% CI: 0.33–5.2, P=0.95); however, the difference was not significant. Studies have documented COVID-19 frequency of 2.4% (4/165) among SLE patients with severe cases mostly in coexisting comorbidities. Even recent consensus has suggested older age, presence of comorbidities, and use of prednisolone ≥10 as a risk factor for poor outcome in these two coexisting diseases. Unlike the previous reports, the present study highlighted the susceptibility of treatment naïve cases of RDs for COVID-19. The RD group either has an almost similar SARS-CoV-2 prevalence as the non-RD group (2.29% vs. 2.17%) or even lowers than the general population (2.29% vs. 7%). In conclusion, RD itself does not seem to be a risk factor for SARS-CoV2 infection, even in treatment naïve patients; however, disease outcome may depend on various coexisting factors/comorbidities. Inter-talk between SARS-CoV-2 and RDs yet to be explored.

Narrative review of autoantibodies in idiopathic inflammatory myopathies.

To discuss the characteristics of autoantigens, detection methods and roles of myositis associated autoantibodies (MAAs) and myositis specific autoantibodies (MSAs), as well as the clinical features of disease subgroups defined by MAAs/MSAs. Autoantibodies in patients with idiopathic inflammatory myopathies (IIMs) are conventionally divided into MAAs and MSAs. MAAs usually refer to autoantibodies which are also available in systematic autoimmune diseases (anti-PM/SCL, anti-Ku, anti-Ro52 and anti-U1RNP antibodies). MSAs refer to autoantibodies which were distinctive for IIM (anti-Mi-2, anti-MDA5, anti-TIF1gammma, anti-NXP2, anti-SAE, anti-synthetase, anti-SRP, anti-HMGCR and anti-cN1A antibodies). The discovery and identification of novel autoantigens is a long and complicated process, which brought light in immunopathogenesis of IIMs. Detection methods of MAAs/MSAs mainly consist of monospecific methods [immunoprecipitation, enzyme-linked immune sorbent assay (ELISA) and indirect immunofluorescence] and multispecific methods [line immunoassay (LIA), dot immunoassay (DIA) and addressable laser bead assay (ALBIA)]. Patients with different MAAs/MSAs have different clinical features and require different clinical management. The search engine PubMed (https://www.ncbi.nlm.nih.gov/pmc/) was used to research the keywords "autoantibodies", "idiopathic inflammatory myopathies", "detection methods" and "clinical features". A narrative review was conducted to literature findings from 1975 to 2020. Development and validation of efficient detection methods of MAAs and MSAs help clinicians for diagnosis, classification and management of IIMs. The exploration of clinical features associated with different autoantibodies that facilitate the creation of diagnostic and classification guidelines and further clinical decision-making is of high value.

Myositis Autoantibodies in Patients with Suspected Post-Treatment Lyme Disease Syndrome.

Most patients suffering from Lyme disease are effectively treated with antibiotics. In some patients, however, problems persist for a long time despite appropriate therapy. The term post-treatment Lyme disease syndrome (PTLDS) is currently used for this condition in scientific literature. The pathogenesis is still not precisely known, but the involvement of immunopathological mechanisms is assumed. In our study, we analyzed the presence of autoantibodies including myositis-specific (MSA) and myositis-associated autoantibodies (MAA) in patients with laboratory proven history of Lyme disease and with clinical symptoms of PTLDS. A total of 59 patients meeting the criteria for PTLDS were enrolled in this study. The control group consisted of 40 patients undergoing differential diagnosis of neurological disorders without clinical and/or laboratory-proven history of Lyme disease. The presence of autoantibodies was determined by immunoblot methods and positive samples were further tested for serum creatine kinase (CK) and myoglobin levels. The presence of myositis autoantibodies was detected in 18 subjects with suspected PTLDS (30.5%), but only in 5% of control subjects exhibiting no evidence of Lyme disease history. The difference was statistically significant (p = 0.002). The subsequent biochemical analysis of muscle-damage markers in positive subjects found a mild elevation in six MSA/MAA-positive PTLDS patients. The study detected raised MSA/MAA autoantibodies formation in the group of PTLDS patients raising the question about their involvement in the pathogenesis of this syndrome.

Clinical Significance of Myositis-Specific and Myositis-Associated Antibody Profiles in Dermatomyositis.

Myositis-specific autoantibodies (MSA) and myositis-associated autoantibodies (MAA) are clinically useful biomarkers that point to the diagnosis, clinical manifestations, and prognosis of dermatomyositis (DM). To estimate the prevalence of MSA as well as MAA and analyze possible clinical correlations of these autoantibodies in patients diagnosed with DM, we conducted a cross-sectional study of 30 patients who were diagnosed with DM. MSA were positive in 19 patients (63%) in which Mi 2 was positive in 8 (27%) patients, and this was the most frequently found MSA. A total of 11 (36.7%) patients showed positive MAA. AntiPM/Scl 75 and anti-Ro 52 were positive in 5 (16.7%) patients each and these were the most commonly found MAA. Anti-La was absent in all our patients. There were 8 (27%) patients in whom both MSA and MAA were positive. Either MSA and/or MAA were positive in 22 (73%) patients. On a bivariate analysis, the patients who were positive for anti-PM/Scl 75 showed a significant difference in manifesting cutaneous ulcers (P value 0.023). It was also found that anti-SAE-positive patients showed a significant difference with malignancy (P value 0.014). Anti-Ro 52-positive patients were less likely to have symmetrical proximal muscle weakness (P value 0.006). All patients who were anti-MDA 5 positive had myositis and none of the anti-MDA 5-positive patients had rapidly progressive interstitial lung disease (RPILD). More than one MSA in the same patient was noted in three patients.

ПОЛИМИОЗИТ: НОВЫЙ ВЗГЛЯД НА СТАРУЮ ПРОБЛЕМУ

Idiopathic inflammatory myopathies are the group of rare heterogeneous autoimmune diseases of unknown etiology, characterized by inflammatory le-sions of the striated muscles and skin, as well as the development of specific organ pathology. The history of the study idiopathic inflammatory myopathies has more than 100 years. Initially, this group of diseases included only 2 main subtypes: dermatomysitis and polymyositis. The latter was the main subtype of myopathies, it corresponded to 2/3 of the clinical descriptions of this pa-thology available at that time. The discovery of myositis-specific and myositis-associated autoantibodies at the end of the 20th century made it possible to significantly expand the understanding of the pathogenesis of idiopathic in-flammatory myopathies. Not only the autoimmune genesis of myopathies was proven, but also their immunological heterogeneity, as well as the existence of clinical and immunological subtypes. Today, with no serological markers, no skin lesions, and no unique histo-logical presentation, polymyositis is a difficult-to-diagnose disease that can of-ten be misdiagnosed in patients with another pathology or subtype of idio-pathic inflammatory myopathies. According to most experts, polymyositis is currently a diagnosis of exclusion and is the rarest subtype of idiopathic in-flammatory myopathies, accounting to no more than 5 % of all cases in this group.

Prevalence of Myositis-Specific Autoantibodies and Myositis-Associated Autoantibodies in COVID-19 Patients: A Pilot Study and Literature Review.

Coronavirus disease 2019 (COVID-19) infection has been linked to numerous autoimmune manifestations. Neither the mechanism nor the etiology of this association has been fully explored or elucidated. Prior studies have detected myositis in patients with proven COVID-19 infection, suggesting a relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the development of myositis. Studies have reported elevated levels of autoimmune antibodies, including myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), in patients with COVID-19 infection, however the prevalence is not well documented. Our objective was to assess the prevalence of MSAs and MAAs in COVID-19 patients compared with unaffected subjects. Serum samples from 74 unvaccinated, polymerase chain reaction (PCR)-positive COVID-19 infected patients were compared with serum samples from 41 healthy, unaffected individuals. All serum samples were tested for MSA and MAA reactivity. Within the COVID-19-positive group, six (8.1%) patients exhibited MSA/MAA positivity, compared with only one (2.4%) individual from the control group. Although a higher prevalence of MSA/MAA positivity was observed within the COVID-19 infected group, the difference did not reach statistical significance (p=0.223). The autoantibodies detected in this study have a unique association with dermatomyositis and other inflammatory myopathies, and may play a role in COVID-19-associated myopathy. This article was previously presented as an abstract at Jacobs School of Medicine and Biomedical Sciences Research Day on June 3rd, 2022.

Randomized Trial of Tocilizumab in the Treatment of Refractory Adult Polymyositis and Dermatomyositis.

To assess the efficacy and tolerability of tocilizumab in a multicenter, randomized, double-blind, placebo-controlled trial in refractory adult patients with dermatomyositis (DM) and polymyositis (PM). Thirty-six subjects with probable or definite DM/PM were enrolled in a 6-month phase 2B clinical trial and randomized 1:1 to receive tocilizumab (8 mg/kg intravenously) or placebo every 4 weeks for 24 weeks. Eligible subjects had either a DM rash, a myositis-associated autoantibody or an adjudicated PM diagnosis. Active disease was defined by at least three of six abnormal core set measures (CSMs), including a manual muscle testing (MMT)-8 score of less than 136/150. If the MMT-8 score was greater than 136, then a cutaneous score of 3 or more (10 cm visual analogue scale) was required along with three additional abnormal CSMs indicating disease activity. The primary endpoint compared the Total Improvement Score (TIS) between both arms from week 4 to 24. Secondary outcomes included time to meeting minimal TIS improvement, changes in CSMs, time to worsening, steroid-sparing effect, proportion of subjects meeting more stringent improvement criteria, and safety outcomes. There was no significant difference (P=0.86) in the TIS over 24 weeks between tocilizumab and placebo arms. The secondary endpoints of time to improvement (minimal, moderate, or major), time to worsening, CSM changes, safety outcomes, and steroid-sparing effect were also not significantly different between arms. Tocilizumab was safe and well tolerated but did not meet the primary or secondary efficacy outcomes in refractory DM and PM in this 24-week phase 2B study.

Anti-FHL1 autoantibodies in juvenile myositis are associated with anti-Ro52 autoantibodies but not with severe disease features.

Four-and-a-half LIM domains 1 (FHL1) is a muscle-specific protein. Autoantibodies against FHL1 were recently discovered in adults with idiopathic inflammatory myopathies (IIMs) and were found to be associated with clinical features and outcomes indicative of increased disease severity. Anti-FHL1 autoantibodies have not been described in children. Here, the prevalence and clinical features associated with anti-FHL1 autoantibodies were examined in a large North American cohort of juvenile patients with IIM. Sera from 338 juvenile IIM patients and 91 juvenile healthy controls were screened for anti-FHL1 autoantibodies by ELISA. Clinical characteristics and HLA alleles of those with and without anti-FHL1 autoantibodies were compared among those with juvenile IIM. Anti-FHL1 autoantibodies were present in 10.9% of juvenile IIM patients and 1.1% of controls. The frequency of anti-FHL1 autoantibodies among clinical and serologic subgroups did not differ. A higher percentage of Asian patients had anti-FHL1 autoantibodies (11% vs 0.7%; P = 0.002). Myositis-associated autoantibodies (MAAs) [odds ratio (OR) 2.09 (CI 1.03, 4.32)], anti-Ro52 autoantibodies specifically [OR 4.17 (CI 1.83, 9.37)] and V-sign rash [OR 2.59 (CI 1.22, 5.40)] were associated with anti-FHL1 autoantibodies. There were no differences in other features or markers of disease severity. No HLA associations with anti-FHL1 autoantibodies in Caucasian myositis patients were identified. Anti-FHL1 autoantibodies are present in ∼11% of juvenile IIM patients and commonly co-occur with MAAs, including anti-Ro52 autoantibodies. In contrast to adult IIM, anti-FHL1 autoantibodies in juvenile myositis are associated with V-sign rash but not with other distinctive clinical features or worse outcomes.