Myositis-associated Antibodies Research Articles

Patient Perspectives of the Manifestations and Treatment of Anti-MDA5 Antibody-Positive Dermatomyositis: An Observational Survey.

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of autoimmune disorders classically characterized by proximal skeletal muscle inflammation leading to weakness, but they often possess additional systemic manifestations such as cutaneous, pulmonary, and articular disease.1 Although originally dichotomized as either dermatomyositis (DM) or polymyositis, the discovery of new myositis-specific antibodies (MSA) and myositis-associated antibodies has led to the delineation of more refined IIM patient subgroups.

Myositis-associated antibodies predict the severity of lung involvement in adult patients with inflammatory myositis - a cohort study of 70 adult patients with myositis in a single center.

Idiopathic inflammatory myopathies (IIMs) encompass a diverse group of diseases characterized by considerable variability in clinical manifestations, antibody profiles, and responsiveness to immunosuppressive therapies. This study aimed to investigate the association between organ involvement and distinct myositis autoantibodies in individuals with IIM in a single-center cohort. Patients with ICD diagnoses M33.1, M33.2, M33.9, or M609 who (1) had been tested with Euroline blot assay for myositis autoantibodies and (2) met the classification criteria of definite/probable polymyositis (PM) or dermatomyositis (DM), anti-synthetase syndrome (ASS), or inclusion body myositis (IBM) were included. Medical journals were retrospectively examined with respect to clinical disease features. Seventy patients (median age 58 years; 66% females) were included and represented the following diagnosis: PM (n = 23), DM (n = 21), ASS (n = 23), and IBM (n = 3). Most of the patients (87%) presented a muscle biopsy indicative of myositis. The presence of autoantibodies was as follows: myositis-specific antibodies, MSA (n = 53), myositis-associated antibodies, MAA (n = 33), both MSA + MAA (n = 24), MSA only (n = 29), MAA only (n = 9), no MSA, or MAA (n = 8). Anti-Jo-1 was the most common MSA (19%), whereas the most common MAA was anti-Ro/SSA52 (31%). We observed a significant association between antibody patterns and lung disease. In our cohort, 47% of the patients in the whole study group, 86% of patients with anti-SSA52, and 100% with anti-Jo-1 had pulmonary involvement. Patients with both MSA and MAA had a higher incidence of lung disease and decreased CO-diffusion capacity. This was especially prominent in anti-Ro/SSA52-positive patients. Interestingly, none of the patients suffered from lung disease if only antibodies against Mi-2α, Mi-2β, NXP2, HMGCR, and TIF1γ were present or no MSA/MAA were detected. The simultaneous presence of both MAA and MSA indicates an increased risk of lung involvement in patients with inflammatory myopathies. The presence of any MAA, and especially anti-Ro/SSA52, is associated with more severe pulmonary disease. Our data suggest that MAA antibodies might be relevant markers for early detection and treatment of lung involvement in IIM.

Nailfold capillaroscopy findings of a multicentric multi-ethnic cohort of patients with idiopathic inflammatory myopathies.

To assess nailfold video capillaroscopic (NVC) abnormalities and their association with clinical features, myositis-specific autoantibodies (MSA), and myositis-associated antibodies (MAA) in a large multi-ethnic cohort of patients with idiopathic inflammatory myopathies (IIM). We recruited 155 IIM patients from three centres in Mexico, Spain, and the USA. We evaluated the clinical and laboratory features of the patients and performed semiquantitative and quantitative analyses of the NVC. Each NVC study was defined as having a normal, non-specific, early systemic sclerosis (SSc), active SSc, or late SSc pattern. Twenty-three patients had at least one follow-up NVC when disease control was achieved. Quantitative variables were expressed as medians and interquartile range (IQR) and were compared with the Kruskal-Wallis, the Mann-Whitney U-test, and the Wilcoxon test for paired medians. Associations between qualitative variables were assessed with the χ2 test. Most patients were women (68.3%), Hispanic (73.5%), and had dermatomyositis (DM) (61.2%). Fourteen patients (9%) had a normal NVC. A non-specific abnormality pattern was the most frequent (53.9%), and was associated with joint involvement, interstitial lung disease, Jo1 autoantibodies, anti-synthetase syndrome, and immune-mediated necrotising myopathy. The SSc pattern was observed mostly in DM and overlap myositis and was associated with cutaneous features and anti-TIF-1g autoantibodies. After treatment, there was a decrease in the capillaroscopic score, the capillary diameter, and the number of avascular areas, and an increase in capillary density and bushy capillary number. NVC abnormalities are related to the diagnosis, clinical features, disease activity, and autoantibodies of patients with IIM.

Clinical and immunological characteristics and prognosis of patients with autoantibody negative dermatomyositis: a case control study.

Myositis-specific antibodies (MSAs) and myositis-associated antibodies (MAAs) are associated with distinctive dermatomyositis (DM)clinical phenotypes. The aim of this study is to explicate the clinical andimmunologicalfeatures of MSAs-negative DM patients. A total of 515 individuals diagnosed with DM was screenedfrom 2013 to 2022 and 220 DM patients were enrolled in this retrospective cohort. Clinical and laboratory data of these patients were analyzed. MSAs-negative DMpatients were categorized into two groups: MAAs-negative(MSAs (-)/MAAs (-)) groupand MAAs-positive (MSAs (-)/MAAs (+))group. The percentage of Raynaud's phenomenon (P=0.026) was higher in the MSAs (-)/MAAs (+) DM patients than the MSAs-positiveDM patients and MSAs (-)/MAAs (-) DMpatients. The proportion of rapidly progressive interstitial lung disease (RP-ILD) in the MSAs-negative DM patients was lower than that in the MSAs-positive group. The MSAs (-)/MAAs (+) group had a higher proportion of organizing pneumoniaand usual interstitial pneumonia (P=0.011), and elevated eosinophils in their bronchoalveolar lavage fluid (P=0.008). Counts of lymphocytes (P=0.001) and CD16+CD56+ natural killer (NK) cells (P=0.012) were higher in the MSAs-negative group. Additionally, the percentage of CD4+TNFα+ (P=0.040), CD4+IFNγ+ (P=0.037), and CD4+IL-2+ (P=0.018) cells among totalCD4+ T cells were higher in the MSA-negative DM patients compared with the MSAs-positive DM patients. Besides, MSAs-negative patients demonstrated a more favorable prognosis than MSAs-positive patients. Multivariable regression analysis identified advanced onsetage, higher level ofcarcinoembryonic antigen (CEA), and RP-ILD as risk factors for mortality in DM patients. Compared with MSAs-positive group,MSAs-negative DM patients suffered less from organ involvement compared with MSAs-positive group and tend to have better prognosis. Key Points MSAs-negative DM patients exhibited distinct characteristics in comparison with MSAs-positive DMpatients: • The MSAs (-)/MAAs (+) DM patientsdemonstrated a higher prevalence of organizing pneumonia (OP)and usual interstitial pneumonia (UIP), and elevated eosinophil counts in bronchoalveolar lavage fluid. • CEA levels were lower in MSAs-negative patients compared with MSAs-positive patients. • Elevated counts of lymphocytes and CD16+CD56+ NK cells were identified in the MSAs-negativepatients. Additionally, proportions of CD4+TNFα+, CD4+IFNγ+, and CD4+IL-2+ cells among total CD4+ T cells were higher in the MSAs-negative DM patients compared with DM MSAs-positive DM patients. • MSAs-negative DMpatients had a more favorable prognosis than MSAs-positive DMpatients. A multivariable regression analysis revealed the advanced onsetage, highCEA levels, and RP-ILD were risk factors for mortality in DM patients.

Utility of positron emission tomography as a new tool for muscle involvement in patients with idiopathic inflammatory myositis: a controlled study.

Idiopathic inflammatory myositis (IIM) represents a rare group of disease that can affect multiple organs in addition to the muscles. 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is an emerging scanning method that is widely used in diagnosing, staging and response to treatment in patients with cancer. In this study, we aimed to evaluate the muscle involvement in PET/CT which was performed for malignancy screening and its correlation with myositis-specific antibodies (MSA) and/or myositis-associated antibodies (MAA) in patients with IIM. IIM patients who fulfilled 2017 EULAR/ACR classification criteria and had PET-CT scans during the active phase of myositis (within two weeks of starting steroids) were included into the study. Age and sex matched participants with history of malignancy (non-IIM patients) were defined as control group. Data of 160 IIM patients were evaluated and 34 patients (of 64.7% female) whose PET/CT results were available, included into the study. Fourteen patients with diagnosis of malignancy without IIM (non-IIM patients) defined as the control group. Sensitivity and specificity of a positive FDG muscle uptake were 37.1% and 100%, 65.7% and 92.9%, 91.4% and 7.1% compared to liver, mediastinum and LTM uptakes, respectively. In multivariate analysis, higher baseline CRP (p=0.017, confidence interval [CI] 95%: 1.03-1.36, OR:1.18) and LDH (p=0.029, CI 95%:1.001-1.017, OR:1.01) levels were associated with muscle PET/CT positivity. In patients with active IIM, median muscle FDG uptake with PET/CT was higher compared to non-IIM. PET/CT may be used for the evaluation of extent and activity in patients with IIM.

High prevalence of circulating myositis-associated antibodies in non-COVID critical illness

High prevalence of circulating myositis-associated antibodies in non-COVID critical illness

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.

Anti-PL-7, anti-Ro/SSA, anti-Mi-2, and anti-TIF1-γ correlate with specific patterns of histopathologic features in dermatomyositis: An analysis of 39 skin biopsy specimens from 25 patients.

In dermatomyositis (DM), myositis-specific and myositis-associated antibodies have been correlated with clinical features. It is unknown if histopathologic findings in lesional skin biopsies correlate with serologic subtypes of DM. A retrospective chart review of patients with DM was performed. Patients with myositis antibodies and DM lesional skin biopsies were included in the study. Skin biopsies were reviewed by blinded dermatopathologists for 20 histopathologic features. There was a statistically significant (p < 0.05) association between anti-PL-7 serology and decreased degree of vacuolar degeneration, necrotic keratinocytes, and thickening of the epidermal basement membrane. Anti-aminoacyl tRNA synthetase (anti-ARS) antibodies had the same significant negative association with degree of vacuolar degeneration, necrotic keratinocytes, and thickening of the epidermal basement membrane. A similar pattern was seen with an anti-cytoplasmic serology; where there was a significant association with an increased degree of vacuolar degeneration and necrotic keratinocytes, and a nonsignificant trend of minimally thickened epidermal basement membrane. There was a statistically significant association between anti-Ro/SSA serology and increased degree of vacuolar degeneration. Anti-TIF1-γ serology was significantly associated with the increased presence of necrotic keratinocytes and pigment incontinence, and displayed a pattern of increased neutrophils. There was a significant association between anti-Mi-2 antibodies and pigment incontinence, as well as between myositis-specific antibodies and pigment incontinence. A statistically significant positive association was found between nuclear antibodies and degree of vacuolar degeneration, thickened epidermal basement membrane, pigment incontinence, and epidermal atrophy. In patients with DM, some specific serotypes, including anti-PL-7, anti-Ro/SSA, anti-Mi-2, and anti-TIF1-γ, may have characteristic histopathologic features.

Dermatomyositis in Association With SARS-CoV-2 Infection or COVID-19 Vaccine.

New-onset and relapsed dermatomyositis (DM) has been reported following SARS-CoV-2 infection or COVID-19 vaccination. This study aims to show the characteristics of a DM cohort after COVID-19 infection and vaccination. A retrospective review was performed on patients treated for DM between March 1, 2020, and October 31, 2022. Charts were evaluated for the presence of new-onset DM or relapse of preexisting DM following either SARS-CoV-2 infection or COVID-19 vaccination. Data on symptom onset, timing of vaccination, type of vaccination, and disease characteristics were collected. Ninety-eight patients treated for DM at our institution in the Division of Rheumatology were included. In total, 12 of 98 patients (12.2%) experienced DM symptoms (either incident or relapse) following either infection or vaccination. Of the 12 patients who developed incident disease or relapse, 7 (58.3%) developed postinfection symptoms, and 8 (66.7%) developed symptoms after vaccination (3 patients had symptoms following both infection and vaccination). The mean onset of symptoms following COVID-19 infection was 3.2 days (median 0.5 days), and mean onset following COVID-19 vaccination was 5.75 days (median 3.5 days). Nine of 12 patients (75%) had a positive myositis-specific antibody, and the remaining 3 (25%) had myositis-associated antibodies. There was no predominant vaccine associated with the development of postvaccination DM symptoms. This retrospective review revealed a strong temporal relationship between DM symptoms and COVID-19 infection or vaccination in 12.2% of all patients with DM evaluated in our clinic during the pandemic. Additional studies are required to understand the possible pathophysiology behind this association.

The Laboratory Test for the Diagnosis of Idiopathic Inflammatory Myopathies

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of autoimmune muscle diseases with systemic involvement. Patients with IIM present with varying degrees of muscle disease, cutaneous manifestations, and internal organ involvement. The diagnosis of IIM is frequently delayed because of non-specific symptoms including weakness, easy fatigability, or myalgia. Laboratory tests can give clues for the diagnosis of myositis and other muscle diseases. Creatine kinase can be the screening tool for muscle diseases. About 40-60% of IIM had positive antinuclear antibody (ANA). Thus, positive ANA results increase the possibility of IIM diagnosis. In addition, the identification of myositis-related autoantibodies can help the diagnosis and classification. Myositis-specific autoantibodies (MSA) are found exclusively in IIMs and facilitate the identification of subsets of patients with relatively homogeneous clinical features. Myositis-associated antibodies are frequently found in association with other MSA; however, they may also be detected in various connective diseases.

Clinical Characteristics and Prognostic Value of Ro52/SSA Antibodies in Idiopathic Inflammatory Myopathies.

Anti-Ro52 are myositis-associated antibodies found in idiopathic inflammatory myopathies (IIMs). This chart review aims to evaluate the frequency, significance, and associated clinical characteristics of Ro52/SSA positivity in IIM patients. We performed a chart review of IIM patients diagnosed between January 2006 and December 2020. All patients met either the 1975 Bohan and Peter or the European League Against Rheumatism/American College of Rheumatology classification criteria for probable or definite myositis. Demographics, clinical and serologic parameters, treatments, and outcomes were compared in patients with anti-Ro52/SSA antibodies and patients without anti-Ro52/SSA antibodies. One hundred eighty-nine patients with IIM were tested for either Ro52 or SSA, with 45 positive for Ro52/SSA (23.8%). Patients with IIM and Ro52/SSA+ were younger at age at onset of disease (44.8 vs. 51.2 years, p = 0.008). Ro52/SSA+ was more common in antisynthetase syndrome (p < 0.001; odds ratio [OR], 4.44; 95% confidence interval [CI], 2.11-9.33) and not frequently identified in clinically amyopathic dermatomyositis (CADM) (p = 0.02; OR, 0.13; 95% CI, 0.02-0.96) or immune-mediated necrotizing myopathy (p = 0.003; OR, 0.14; 95% CI, 0.03-0.63). Of the extraskeletal muscle manifestations, interstitial lung disease (ILD) was strongly associated with Ro52/SSA+ (p < 0.001; OR, 6.61; 95% CI, 3.15-13.86), as was dysphagia (p = 0.006; OR, 2.73; 95% CI, 1.31-5.71). Interstitial lung disease pattern and pulmonary function testing impairment did not differ based on antibody status. There was no significant difference in outcomes between groups. In this myositis cohort, Ro52/SSA+ was present in nearly one-fourth of the population and had a strong association with the antisynthetase syndrome subtype, ILD, and dysphagia. Although these disease manifestations are associated with significant morbidity, in our cohort, they were not associated with increased mortality or more severe ILD.

Value of the HFA-PEFF diagnostic algorithms for heart failure with preserved ejection fraction to the inflammatory myopathy population

ObjectivesThe HFA-PEFF score has been validated to hold great diagnostic and prognostic utility for heart failure with preserved ejection fraction (HFpEF). Idiopathic inflammatory myopathy (IIM) is recognized as one of the potential etiologies underlying HFpEF. Here, we intended to investigate the real prevalence of HFpEF in IIM via the HFA-PEFF score and explore the prognostic value of this score.MethodsTwo hundred twenty IIM patients were enrolled for assessment. The cohort was divided into low, intermediate and high tertiles of the HFA-PEFF score. Spearman’s correlation analysis was used to explore the association between the score and disease activity. Chi-square test was applied to investigate the distribution discrepancy of HFA-PEFF tertiles among patients with different myositis-specific antibodies (MSAs) or myositis-associated antibodies (MAAs). Univariate and multivariate ordinal regression analyses were performed to screen risk factors for high HFA-PEFF scores. Survival curves were obtained using the Kaplan–Meier method and log-rank tests.ResultsIn total, 79 (35.9%), 107 (48.6%) and 34 (15.5%) patients were rated low, intermediate and high probability of HFpEF, respectively. The HFA-PEFF score correlated well with disease activity. Patients with positive AMA-M2 scored higher in the HFA-PEFF score (p = 0.011). During follow-up, patients with positive AMA-M2 or anti-SRP antibody developed an inclination towards concentric hypertrophy on echocardiography. Additionally, palpitation symptom, AMA-M2 positivity and elevated serum levels of LDH, cTnI were independent risk factors for high HFA-PEFF scores. Finally, a high-tertile HFA-PEFF score was related to lower overall survival rate (p < 0.001). Patients with positive AMA-M2 had poorer outcomes (p = 0.002).ConclusionHFpEF was prevailing in IIM patients according to the HFA-PEFF score. The HFA-PEFF score correlated well with disease activity and held significant prognostic value. Patients with AMA-M2 antibody were prone to have poor outcomes.

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.

Myositis-associated interstitial lung disease.

In idiopathic inflammatory myopathies (IIMs), interstitial lung disease (ILD) is common and the autoantibody profile, made up of myositis-specific and myositis-associated (MSA and MAA) antibodies, can predict the clinical phenotype and progression over time. This review will focus on the characteristics and management of antisynthetase syndrome related ILD and anti-MDA5 positive ILD, which are the most clinically relevant subtypes. The prevalence of ILD in IIM has been estimated in Asia, North America and Europe at 50, 23 and 26%, respectively, and is increasing. In antisynthetase syndrome related ILD, the clinical presentation, progression and prognosis varies among anti-ARS antibodies. ILD is more common and severe in patients with anti-PL-7/anti-PL-12 antibodies when compared with anti Jo-1 patients. The prevalence of anti-MDA5 antibodies is higher in Asians (11-60%) than in whites (7-16%). Sixty-six percent of antisynthetase syndrome patients had 'chronic ILD' compared with the more rapidly progressive ILD (RP-ILD) seen in 69% of patients with anti-MDA5 antibodies. ILD is most common in the antisynthetase subtype of IIM and can be a chronic indolent or RP- ILD. The MSA and MAAs are associated with different clinical phenotypes of ILD. Treatments typically involve combinations of corticosteroids and other immunosuppressants.

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.

Prevalence of myositis specific and associated antibodies in a cohort of patients affected by idiopathic NSIP and no hint of inflammatory myopathies.

The presence of interstitial lung disease (ILD) is a common and fearsome feature of idiopathic inflammatory myopathies (IIM). Such patients show radiological pattern of non-specific interstitial pneumonia (NSIP). The present study aimed to assess the prevalence of myositis-specific and myositis-associated antibodies (MSA and MAA) in a cohort of patients with a previous diagnosis of NSIP and no sign or symptom of IIM. Secondly, it will be assessed whether patients displaying MSA and/or MAA positivity have a worse or a better outcome than idiopathic NSIP. All patients affected by idiopathic NSIP were enrolled. MSA and MAA were detected using EUROLINE Autoimmune Inflammatory Myopathies 20 Ag (Euroimmun Lubeck, Germany), line immunoassay. A total of 16 patients (mean age 72 ± 6.1years old) were enrolled. Six out of 16 patients (37.5%) had significant MSA and/or MAA positivity: one displayed positivity of anti-PL-7 (+ +), one of anti-Zo (+ +), anti-TIF1γ (+ + +) and anti-Pm-Scl 75 (+ + +), one of anti-Ro52 (+ +), one of anti-Mi2β (+ + +), one of anti-Pm-Scl 75 (+ + +) and the latter of both anti-EJ (+ + +) and anti-Ro52 (+ + +).Two out of 7 seropositive patients showed a significant impairment of FVC (relative risk 4.8, 95% CI 0.78-29.5; p = 0.0350). Accordingly, among the 5 patients that started antifibrotic treatment during the observation time, 4 were seronegative. Our findings highlighted a potential autoimmune or inflammatory in idiopathic NSIP patients and also in those without significant rheumatological symptoms. A more accurate diagnostic assessment may ameliorate diagnostic accuracy as well as may provide new therapeutic strategy (antifibrotic + immunosuppressive). A cautious assessment of NSIP patients with a progressive and non-responsive to glucocorticoids disease course should therefore include an autoimmunity panel comprising MSA and MAA.

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.

Complement C4 gene copy number variations and polymorphisms, autoantibodies, and clinical manifestations of juvenile dermatomyositis– a multi-center study

Abstract Juvenile dermatomyositis (JDM) is an autoimmune myopathy characterized by rash and muscle weakness. Complement C4 gene copy number (GCN) variation is a known risk factor for JDM. JDM patients often develop autoantibodies. We investigated the relationship between C4 GCN, clinical features, and antibody development. METHODS: Subjects were recruited (n=255) from the US, Sweden, and the Czech Republic. C4 GCN was determined by real time PCR. Comparative analyses were performed via student’s t test or Mann Whitney U test. Correlation was assessed via linear regression or Fisher’s exact test. All studies were IRB approved, and informed consent was obtained. RESULTS: C4 GCN correlated with muscle pathology and extra-muscular disease at diagnosis. Lower C4A and C4L GCN were associated with a higher number of abnormal muscle enzymes (p=0.0062 and p=0.0029), while the opposite was true for C4S (p=0.024). Higher C4S GCN correlated with lower muscle strength scores (p=0.039). Lower C4L correlated with abnormal MRI (p= 0.042). C4B GCN correlated with dysphagia (p=0.035). Higher GCN of C4S was a risk factor for arthritis (p=0.032), systemic symptoms (p=0.020), and dysphagia (p=0.0078). C4 GCN was associated with myositis-specific (MSA) and myositis-associated (MAA) antibodies. Patients with homozygous C4A deficiency were more likely to test positive for anti-NXP2 (OR 20.0, p=0.011), and C4A GCN was lower in anti-NXP2 positive subjects (p=0.030). A higher C4B GCN correlated with positive MAA (p=0.043). DISCUSSION: Here, we show that low C4A/C4L GCN and high C4B/C4S GCN correlate with worse muscle disease, extra-muscular pathology, and autoantibodies. Our data suggest that complement C4 may play a key role in the ongoing pathogenesis of JDM. Supported by grants from NIH (R21 AR070509) and the CureJM Foundation

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.

Cancer-associated Regional Ischemic Myopathy: A Rare Immune Myopathy (P9-8.008)

<h3>Objective:</h3> To describe clinical and pathological features of a rare immune myopathy featured by regional ischemia in the setting of cancer. <h3>Background:</h3> Regional ischemic immune myopathy (RIIM) is a rare disorder attributed to myovasculopathy and considered paraneoplastic. It has a high mortality rate. Contrary to dermatomyositis, where microvasculopathy leads to perifascicular pathology and sometimes muscle ischemia, RIIM is characterized by regional necrosis in border zones between perimysial vessels. <h3>Design/Methods:</h3> Review of patient’s clinical and laboratory findings. <h3>Results:</h3> An 81-year-old man manifested subacute proximal limb weakness, dysphagia, and 25-pound weight loss. He had stage IV prostate cancer, diagnosed 3 months prior to weakness-onset. Examination revealed mild facial weakness, flaccid dysarthria, moderate-to-severe neck and limb girdle weakness and atrophy. Videofluoroscopic swallow study showed severe oropharyngeal dysphagia with aspiration. CK was 689 U/L (normal 39–108 U/L) at presentation but 6,145 U/L six weeks earlier. Myositis-associated and HMGCR antibodies were negative. EMG showed proximal-predominant myopathic changes with fibrillation potentials. Muscle biopsy revealed several well-demarcated areas of ischemia involving adjacent fascicles. Necrotic fibers were in a similar early stage of necrosis with no macrophagic infiltration and diffuse sarcoplasmic C5b-9 deposition. A few small collections of perimysial perivascular inflammatory cells were present in the areas of the specimen not affected by ischemia. There was patchy capillary depletion and dilation; some capillaries in areas not affected by ischemia showed complement deposition. Myxovirus resistance protein A (MxA) expression occurred diffusely, especially in necrotic fibers, but without perifascicular predominance. Patient received IVIG 2g/Kg and prednisone 40 mg daily. The limb weakness stabilized while the dysphagia progressed. He expired 3 weeks later. <h3>Conclusions:</h3> RIIM is a rare myovasculopathy leading to muscle weakness in the setting of cancer. In keeping with published data, it has a poor prognosis. The identification of RIIM myopathological changes should trigger the search for underlying malignancy in patients without known cancer. <b>Disclosure:</b> Dr. Granger has nothing to disclose. Dr. Soontrapa has nothing to disclose. Dr. Klein has a non-compensated relationship as a Klein with Neurology Journal that is relevant to AAN interests or activities. Dr. Milone has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenx. Dr. Milone has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Neurology Genetics, AAN. The institution of Dr. Milone has received research support from Mayo Clinic, CCaTS-CBD. The institution of Dr. Milone has received research support from Mayo Clinic, SGP Award. The institution of Dr. Milone has received research support from MDA for Care Center grant. The institution of Dr. Milone has received research support from Regenerative medicine Minnesota.