Anti-aminoacyl tRNA Synthetase Research Articles

Treatment Strategies for Anti-Synthetase Syndrome

Anti-aminoacyl tRNA synthetase (ARS) antibodies are the most frequent in idiopathic inflammatory myopathy, notably associated with anti-synthetase syndrome (ASyS), which is characterized by six clinical features: arthritis, myositis, interstitial lung disease (ILD), fever, Raynaud's phenomenon, and mechanical hands. Although patients with ASyS often respond well to initial glucocorticoid (GC) therapy, they tend to have a chronic, recurrent disease course. In anti-ARS-positive patients, the treatment goal involves suppressing disease recurrence and progression while achieving a minimal GC dose. In this regard, the administration and continuation of immunosuppressants, such as calcineurin inhibitors, have been suggested. B-cell depletion therapies are expected to be valuable in patients with refractory ASyS. Moreover, additional antifibrotic agents may be beneficial for patients with progressive fibrosing ILD.

P133 Anti-synthetase syndrome: an experience from a tertiary referral center

Abstract Background/Aims Anti-synthetase syndrome (ASS) is a subset of Idiopathic inflammatory myositis (IIMs). It is a syndromic diagnosis classified by Connors et al. and Solomon et al. criteria. Raynaud’s phenomenon (RP), fever, arthritis, mechanics hands, ILD and myositis constitute this syndrome along with the classical Anti-aminoacyl tRNA synthetase antibodies (ARS). About 25% of IIMs patients are classified as ASS. This study was planned to evaluate the prevalence of ASS; their phenotype, antibody subtypes, treatment responsiveness and outcomes. Methods All consecutive ASS patients were enrolled in the study fulfilling Connors et al. criteria during January, 2016 to August2023. Their demographic details, clinical features, laboratory and imaging features, treatment were analyzed. ARS were considered positive on a Line Immunoassay with cutoff >6U/ML using BlueDriverQuantrix-ANA25 Screen IgG kit (includes Jo1, Pl-7, Pl-12) from D-tek, Belgium including three ASS antibodies (Jo-1, PL-12, PL-7). Anti EJ, OJ antibodies were not present in the kit. Descriptive analysis were used to describe disease characteristics. Results Among 139 total IIM patients, 21(15%) patients were diagnosed with ASS. All patients fulfilled Connors et al. criteria while 66.6% patients fulfilled stricter criteria by Solomon et al. Mean(±SD) age group was 43(±16.4) years. 71.4% were Females. Anti Jo-1 was the predominant antibody seen in 66.6% while Anti PL-12 and Anti Pl-7 antibodies were present in 19% and 14.3% respectively. 66.6% had ANA positivity and MAA antibodies were seen in 52.3%. Rash was seen in 61.9%, mechanics hands in 38%, RP in 52.3% fever in 38% ,arthritis in 57%, myositis 62% and ILD in 80.9%. NSIP (66.6%) was the predominant type, followed by OP (9.5%) and UIP (4.7%). Median (IQR) CPK level was 736 (210-4556)U/L. Anti Jo-1 patients had higher prevalence of mechanics hands and rash whereas ILD was observed in all cases of Anti PL-7 and Anti PL-12 antibodies. Malignancy was seen in two patients (Malignant fibrous histiocytoma, Metastatic Pancreatic carcinoma). Mean (SD) MMT8 score was 62.8(±22.2) at presentation . Treatment is with steroids in all cases followed by maintenance with azathioprine in 57.1%, Methotrexate in 14.2%. Rituximab was used in 14.2%, cyclophosphamide in 9.5% and mycophenolate mofetil in 23.8%. Mortality was seen in one patient with respiratory failure. Lung involvement was severe in patients with both MSA and MAA positivity. 62% patients were in remission. Conclusion ILD and Arthritis were the main presenting complaints in our cohort. Myositis is relatively less prevalent in ASS. NSIP was the predominant ILD subtype. Non Jo-1 group had high MAA positivity. Jo-1 was associated with mechanic’s hands and rash. Malignancy was less prevalent in ASS. All patients with PL-7 and PL-12 antibodies had lung involvement. Biologics were required in few refractory cases. Disclosure P. Khatri: None. J.R. Yadavalli: None. S. Dhuria: None. N. Negalur: None. K. Shivam: None. R. Gupta: None.

Characteristics of chest high-resolution computed tomography in patients with anti-aminoacyl-tRNA synthetase antibody-positive interstitial lung disease.

Anti-aminoacyl-tRNA synthetase (ARS) antibodies form a condition called Antisynthetase syndrome (ASSD). While interstitial lung disease (ILD) is a particularly frequent manifestation of ASSD and is closely associated with morbidity and mortality, few studies have been conducted on its characteristics on high-resolution computed tomography (HRCT). In this study, we clarified the HRCT findings in patients with anti-ARS antibody-positive ILD (ARS-ILD). Methods: The HRCT findings at the time of the ILD diagnosis in 24 ARS-ILD patients were retrospectively evaluated by 2 pulmonologists and one radiologist. We also assessed the clinical symptoms, physical examination findings, and laboratory data including the type of anti-ARS antibodies. For a further analysis, the data of patients were divided into two groups: the polymyositis (PM)/dermatomyositis (DM) group and the non-PM/DM group. The ratio of men to women was almost 1:1. The median age at the time of the diagnosis was 53 years old. Anti-glycyl (anti-EJ) and anti-histidyl (anti-Jo-1) antibodies were more common than others. An analysis of the HRCT patterns of 23 ARS-ILD patients showed that the most common pattern was the nonspecific interstitial pneumonia (NSIP) pattern. The second most common pattern was the usual interstitial pneumonia (UIP) pattern. Between the PM/DM and non-PM/DM groups, no clear trends were noted in the age, sex ratio, proportion of HRCT patterns, or type of anti-ARS antibodies. This retrospective study demonstrated that ARS-ILD patients, regardless of myositis symptoms, most often showed the NSIP pattern on HRCT, as previously reported. However, unlike previous reports, the UIP pattern on HRCT was not rare.

Anti-aminoacyl tRNA synthetase antibodies showing the discrepancy between enzyme-linked immunosorbent assay and RNA-immunoprecipitation

Anti-aminoacyl-tRNA synthetase (ARS) antibodies are myositis-specific antibodies associated with anti-synthetase syndrome (ASSD). Some patients are positive for anti-ARS antibodies on enzyme-linked immunosorbent assay (ELISA) but negative on RNA-immunoprecipitation (RNA-IP) (the gold standard method). Whether these patients should be considered truly positive for anti-ARS antibodies remains unclear. Therefore, we investigated the clinical characteristics of these patients and verified the authenticity of their anti-ARS positivity. Patients who were positive for anti-ARS antibodies on ELISA were divided into the non-discrepant (positive on RNA-IP, n = 52) and discrepant (negative on RNA-IP, n = 8) groups. Patient clinical characteristics were compared between the groups. For each positive individual, the authenticity of anti-ARS antibody positivity on ELISA was cross-examined using protein-IP and western blotting. All patients in the discrepant group had lung involvement, including five (63%) with interstitial lung disease. The overall survival time was significantly lower in the discrepant group than in the non-discrepant group (p < 0.05). Validation tests confirmed the presence of anti-ARS antibodies in the sera of the discrepant group but indicated different reactivity from typical anti-ARS antibodies. In conclusion, some anti-ARS antibodies are detected by ELISA but not RNA-IP. Such anti-ARS antibody discrepancies need further elucidation to attain validation of the diagnostic process in ASSD.

Secondary Pulmonary Alveolar Proteinosis Development during the Treatment for Anti-aminoacyl-tRNA Synthetase Antibody-positive Interstitial Lung Disease.

A 70-year-old woman with anti-aminoacyl-tRNA synthetase (ARS) antibody-positive interstitial lung disease (ARS-ILD) received daily medications and regular cyclophosphamide cycles for recurring exacerbations. Approximately four years after immunosuppression initiation, the patient was admitted for progressive dyspnea on exertion. Chest computed tomography (CT) findings were suggestive of acute exacerbation. Despite intensified immunosuppressive treatment, the radiographic findings worsened, and serum Krebs von den Lungen-6 (KL-6) levels increased. A bronchoalveolar lavage fluid (BALF) examination revealed amorphous globules and alveolar macrophages with eosinophilic granules. Owing to negative anti-GM-CSF antibody tests, a diagnosis of secondary pulmonary alveolar proteinosis (PAP) was established.

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.

Immune cell profiles of idiopathic inflammatory myopathy patients expressed anti-aminoacyl tRNA synthetase or anti-melanoma differentiation-associated gene 5 autoantibodies

BackgroundPatients with idiopathic inflammatory myopathy (IIM) often express a different type of myositis-specific autoantibodies (MSAs), each associated with different clinical symptoms. Understanding the immunopathogenesis of various IIM subgroups can help improve the diagnosis and prognosis of IIM patients with different MSAs. However, the immune cell profiles of these IIM patients with anti-aminoacyl tRNA synthetase (ARS) or anti-melanoma differentiation-associated gene 5 (MDA5) autoantibodies remain unclear. We focused on the immune cell profiles of IIM patients with anti-ARS or anti-MDA5 autoantibodies.ResultsThe peripheral blood from IIM patients with anti-MDA5 autoantibody (MDA5 + group, n = 24) or one of the anti-ARS autoantibodies (ARS + group, n = 40) autoantibodies, and healthy controls (HC group, n = 60) were collected and examined. We found that IIM patients had a lower CD3 T cell population compared to the HC group. IIM patients showed a significantly lower TN cell population and a higher TEMRA cell population. Higher Th17 and Treg cell populations were found in these IIM patients than in the HC group. In these IIM patients, the MDA5 + group exhibited the higher percentages of Th17 and Treg cells than the ARS + group. It is noteworthy that the percentage of Th1 cells in the survival subgroup was higher than in the death subgroup in IIM patients with ARS + or MDA5 + . Furthermore, in the MDA5 + group, the percentage of Treg cells was higher in the survival subgroup compared to the death subgroup.ConclusionsOur study demonstrated that elevated Th1 may be a good prognostic indicator in IIM patients with ARS + or MDA5 + . Elevated Treg may also help predict a good prognosis in MDA5 + IIM patients. However, more large-scale studies and clinical samples are needed to verify the significance of Th1 and Treg cell subsets in clinical outcomes for these IIM patients with ARS + or MDA5 + . These data may help design a therapeutic approach that specifically targets the pathogenic immune molecular responsible for autoimmune attacks in IIM.

Antisynthetase Syndrome-Associated Myositis

Antisynthetase syndrome-associated myositis is a major form of autoimmune myositis defined by the presence of anti-aminoacyl tRNA synthetase autoantibodies. It involves the skeletal muscle as well as the lungs, joints, and skin. Severity of each symptom varies by autoantibody subtype; anti-OJ is associated with severe muscle involvement. Pathological changes from the perimysium to the adjacent perifascicular area, including perifascicular necrosis, is a distinctive feature. The skeletal muscle provides an immunological micro-milieu for specific plasma cells. Therapies against plasma cells or factors defining B cell/plasma cell niche may be a more effective mechanism-specific treatment.

Positive Autoantibody Is Associated with Malignancies in Patients with Idiopathic Interstitial Pneumonias.

Various autoantibodies are associated with clinical outcomes in patients with idiopathic interstitial pneumonias (IIPs). We retrospectively analyzed the association between autoantibodies and malignancies in IIP patients. Comprehensive analyses of autoantibodies were performed using immunoprecipitation and enzyme-linked immunosorbent assays in 193 consecutive IIP patients. Cancer-related factors were analyzed using logistic regression analysis. In total, 22 of 193 patients (11.4%) with IIP had malignant disease. In univariate analysis, positivity for any autoantibody (odds ratio (OR), 3.1; 95% confidence interval (CI), 1.2–7.7; p = 0.017) and antinuclear antibody titer ≥1:320 (OR, 3.4; CI, 1.2–9.8; p = 0.024) were significantly associated with malignancies. Positive anti-aminoacyl tRNA synthetase (ARS) (OR, 3.7; CI, 0.88–15.5; p = 0.074) and anti-Ro52 antibody (OR, 3.2; CI, 0.93–11.2; p = 0.065) tended to be associated with malignancies. In multivariate analysis, independent risk factors were male sex (OR, 3.7; CI, 1.0–13.5; p = 0.029) and positivity for any autoantibody (OR, 3.9; CI, 1.5–10.1; p = 0.004) in model 1, and male sex (OR, 3.9; CI, 1.0–15.3; p = 0.049), antinuclear antibody titer ≥1:320 (OR, 4.2; CI, 1.4–13.3; p = 0.013), and positivity for anti-ARS antibody (OR, 6.5; CI, 1.2–34.1; p = 0.026) in model 2. Positivity for any autoantibody, antinuclear and anti-ARS antibodies, and male sex were independent risk factors for malignancies in IIP patients. Testing autoantibodies in IIP patients might help the early diagnosis of malignancies.

UNUSUAL CASE OF ANTI-SYNTHETASE SYNDROME CORRELATED WITH EXPOSURE TO COVID-19 INFECTION OR VACCINE

UNUSUAL CASE OF ANTI-SYNTHETASE SYNDROME CORRELATED WITH EXPOSURE TO COVID-19 INFECTION OR VACCINE

Mortality Risk Stratification Using Cluster Analysis in Patients With Myositis-Associated Interstitial Lung Disease Receiving Initial Triple-Combination Therapy.

ObjectiveTo stratify patients with polymyositis/dermatomyositis-associated interstitial lung disease (ILD) who were initially treated with an intensive regimen consisting of high-dose corticosteroids, a calcineurin inhibitor, and intravenous cyclophosphamide (triple-combo therapy) into subgroups based on mortality outcomes by a cluster analysis using a large-scale multicenter retrospective cohort of Japanese patients with myositis-associated ILD (JAMI).MethodsTwo-step cluster analysis of preclustering and subsequent hierarchical clustering was conducted in 185 patients who received triple-combo therapy in an unbiased manner. Initial predictors for mortality previously reported in patients with myositis-associated ILD were used as variables and included age, sex, disease duration, classification of myositis, requirement of supplemental oxygen, anti-aminoacyl tRNA synthetase (ARS) antibody, anti-melanoma differentiation-associated gene 5 (MDA5) antibody, and serum levels of C-reactive protein (CRP) and Krebs von den Lungen-6 (KL-6). The cluster model was further applied to 283 patients who received conventional regimens consisting of corticosteroids with or without a single immunosuppressive agent (dual-combo therapy or monotherapy). Cumulative survival rates were compared using Kaplan-Meier analysis, and the log-rank test was used to test for significant differences between two groups.ResultsWe developed a cluster model consisting of 6 clusters, which were categorized by age at onset, clinically amyopathic dermatomyositis, CRP, KL-6, requirement of supplemental oxygen, anti-ARS antibody, and anti-MDA5 antibody. This model was judged to be of good quality based on the silhouette measure of cohesion and separation of 0.6. These clusters were regrouped into three subsets based on low (<10%), moderate (10-50%), and high (>50%) mortality rates. The performance of the clustering was generally replicated in patients who received initial dual-combo therapy or monotherapy. Survival benefits of triple-combo therapy over dual-combo therapy or monotherapy were not observed in any of the clusters.ConclusionWe successfully developed a cluster model that stratified patients with myositis-associated ILD who were treated with initial triple-combo therapy into subgroups with different prognoses, although this model failed to identify a patient subgroup that showed survival benefits from triple-combo therapy over dual-combo therapy or monotherapy.

Interstitial Lung Disease in Dermatomyositis Without Myositis-Specific and Myositis-Associated Autoantibodies: Study of a Series of 72 Patients From a Single Cohort.

ObjectiveThe clinical features of interstitial lung disease (ILD) in patients with dermatomyositis (DM) and negative myositis autoantibodies had not been exactly demonstrated previously. This study aimed to describe and expand the phenotype of interstitial lung disease (ILD) in this cohort of patients.MethodsA total of 1125 consecutive Chinese patients with idiopathic inflammatory myopathies (IIM) between 2006 and 2020 were screened retrospectively. All proven cases of isolated ILD with both negative myositis-specific autoantibodies (MSA) and negative myositis-associated autoantibodies (MAA) were selected for inclusion. The clinical features and outcome among this group, MDA5+DM (DM patients with positive anti-MDA5 antibody) and ASS (patients with positive anti-aminoacyl tRNA synthetases antibodies were recorded and compared.ResultsOf 1125 IIM patients with an average follow-up of 6 years, 154 DM patients with negative MSA and MAA (MSA/MAA) were identified, with an ILD incidence of 46.8%. DM-ILD Patients with negative MSA/MAA presented younger age at onset (p<0.001), lower incidence of elevated CA153 (p=0.03) and fever (p=0.04)than those ILD patients with MDA5+DM and ASS.The estimated high-resolution computed tomography patterns of ILD showed non-specific interstitial pneumonia (66.6%), followed by organizing pneumonia in patients with negative MSA/MAA. OP pattern was more common in patients with MDA5+DM (69.7%), and the ratios of the OP (48.7%) and NSIP (51.3%) patterns were almost equal in patients with ASS. Of these DM-ILD patients with negative MSA/MAA, 25% developed rapidly progressive interstitial lung disease (RP-ILD). Patients with RP-ILD had a shorter disease duration (p=0.002), higher percentage of positive ANA(p=0.01) and organizing pneumonia patterns (p=0.04), elevated CYFRA211(p=0.04) and decreased FiO2/PaO2 (p<0.001) than those with chronic progressive ILD. The incidence of OP pattern in RP-ILD patients with negative MSA/MAA was lower than in those RPILD patients with MDA5+ DM (75%) and ASS (89%) (p=0.006). The cumulative 5- and 10-year survival rates in the DM-ILD patients with negative MSA/MAA were 91% and 88%, respectively, during the long-term follow-up study. And they had more favorable survival rate compared with ILD patients with MDA5+DM and ASS (p<0.001). An independent prognostic factor was identified as decreased PaO2/FiO2 (hazard ratio, 0.97; p=0.004].ConclusionsThis study indicates DM-ILD patients with negative MSA/MAA had favorable long-term outcomes. Decreased baseline PaO2/FiO2 acted as an independent prognostic factor for this group of patients.

P225 A case of PL-7 positive amyopathic dermatomyositis associated with autoimmune liver disease

Abstract Background/Aims Amyopathic dermatomyositis (ADM) is a variant of dermatomyositis (DM) characterized by the presence of pathognomonic skin features of dermatomyositis but without clinical muscle weakness. ADM is believed to account for about 20% of cases of DM. Methods We present the case of a 40-year-old lady who presented in May 2020 with a 6-week history of periorbital oedema and a heliotrope rash. She had a past medical history of rectosigmoiditis diagnosed on colonoscopy in 2018 managed with mesalazine 2g once a day. Blood tests revealed a transaminitis (ALT 372 u/l, AST 201 u/l). Full blood count was normal as were inflammatory markers (ESR 4 mm/hr, CRP 2 mg/dl) and renal function (creatinine 63.9 umol/l). CK was normal (72 u/l). A non-invasive liver screen including hepatitis B and C, caeruloplasmin, alpha-fetoprotein and anti-mitochondrial antibodies was negative. A liver ultrasound was reported as normal. An ANA was positive and an ENA screen revealed positive RNP-68, S/RNP and anti-smooth muscle antibodies. Atypical pANCA antibodies were also positive. A myositis antibody screen revealed a positive PL-7 antibody. A skin biopsy of the affected area around the eye demonstrated prominent dermal periadnexal and perivascular chronic inflammation composed mainly of lymphocytes and plasma cells consistent with a connective tissue disease. A liver biopsy confirmed autoimmune liver disease (AILD). Tumour markers (CEA, CA 125 and CA 19-9) were normal and a CT scan of the chest, abdomen and pelvis to rule out occult malignancy was normal. Full lung function tests including transfer factor were normal. A diagnosis of PL-7 positive ADM with associated AILD was made. Results The patient’s ADM and AILD were successfully treated with a reducing course of budesonide (6mg three times daily for 4 months reduced to 3mg twice daily for four months then 3mg daily for 3 months) and mycophenolate mofetil 720mg twice daily. Currently, 16 months after her initial presentation, the patient’s ADM and AILD are in remission and she remains on mycophenolate mofetil 720mg twice daily. Conclusion Anti-PL-7 is one of a number of anti-aminoacyl tRNA synthetase (ARS) antibodies that are associated with DM, polymyositis (PM) and ADM. Other anti-ARS antibodies include Jo-1, PL-12, EJ, OJ, KS, ZO and YRS/HA. Antibodies to PL-7 have been reported to be associated with milder muscle involvement than antibodies to Jo-1. Antibodies to PL-7 have been associated with severe interstitial lung disease (ILD). An association between AILD and inflammatory myositis has been reported in the literature but only in a handful of case reports. To the best of our knowledge however, AILD has not previously been reported in PL-7 positive DM, PM or indeed ADM. Disclosure M.A. Lee: None. V. Scott-Lang: None. K. Raja: None. S. Sahu: None.

Autoimmune pulmonary alveolar proteinosis exacerbated by steroid therapy due to misdiagnosis as anti-aminoacyl-tRNA synthetase (ARS) antibody positive- interstitial pneumonia: a case report

BackgroundAnti-aminoacyl-tRNA synthetase (anti-ARS) antibodies are myositis-specific autoantibodies that have been identified in a subset of patients with interstitial pneumonia who do not present with dermatomyositis or polymyositis. Anti-ARS antibody-positive interstitial pneumonia is commonly treated with steroids or immunosuppressive agents and is usually responsive to these therapies. Here, we present in detail a case in which respiratory failure of a patient diagnosed with anti-ARS antibody-positive interstitial pneumonia was exacerbated by treatment with steroids and immunosuppressive agents. Further examination revealed misdiagnosis of this patient and a subsequent diagnosis of autoimmune pulmonary alveolar proteinosis.Case presentationA 66-year-old man presented to the hospital with dyspnea on exertion, which resulted in the detection of interstitial pneumonia. Serum anti-ARS antibodies were detected; however, there were no other findings suggestive of myositis. Pulmonary alveolar proteinosis (PAP) was suspected based on the marked increase in serum KL-6 and chest computed tomography findings. The bronchoalveolar lavage revealed no milky changes in the lavage fluid. After treatment with steroids and initiation of immunosuppressive agents for anti-ARS antibody-positive interstitial pneumonia, respiratory failure and chest imaging findings showed worsening of the condition. Bronchoscopy was repeated, and milk-like alveolar lavage fluid was collected; serum anti-granulocyte macrophage colony-stimulating factor antibody was identified. Steroids and immunosuppressive agents were gradually tapered and discontinued, and the patient’s condition stabilized after repeated alveolar lavage under general anesthesia.ConclusionDue to similar presentation, PAP can be misdiagnosed as interstitial pneumonia. If pulmonary lesions due to interstitial pneumonia are exacerbated by immunosuppressive treatment, physicians should reconsider the diagnosis and include PAP in the differential diagnosis.

HP42: EMG is a potential biomarker for myositis in patients with antisynthetase syndrome without muscle symptoms

Anti-aminoacyl-tRNA synthetase (ARS) antibodies positive patients sometimes present interstitial lung disease (ILD) without muscle symptoms. We investigated needle electromyography (nEMG) to explore whether there are some myogenic changes or not in patients with antisynthetase syndrome without muscle symptoms. Method: We enrolled three patients who fulfilled anti ARS antibodies positive and ILD of the Connor's criteria for antisynthetase syndrome, and not fulfill the PM/DM criteria. We investigated the nEMG, and magnetic resonance imaging (MRI) of muscles to explore whether there are some myogenic changes or not. Serum creatine kinase (CK), manual muscle testing of 8 muscle groups (MMT8), Inclusion Body Myositis-Functional Rating Scale (IBM-FRS) were measured. This study was approved by the ethics committee of the Nara Medical University School of Medicine. Results: All subjects were females and their ages at the examination were 54 years old (P1), 44(P2) and 69(P3). P1 and P2 had already initiated oral steroid therapy. Although all three patients had no high serum CK level nor decline in IBM-FRS, nEMG revealed that abnormally short durations of the motor unit potential (MUP) patterns in the deltoid and biceps. P3 presented the same MUP pattern in vastus lateralis. MRI revealed inflammatory changes in P2 at left triceps and P3 at anterolateral femurs and posterolateral lower legs. Conclusion: nEMG is usually performed when patients exhibit muscle weakness, but this examination tool can be applicated to detect muscle damage in patients with anti-ARS antibody-associated ILD, prior to muscle weakness, myalgia, and declines in ADLs.

A Comparison of Line Blots, Enzyme-linked Immunosorbent, and RNA-immunoprecipitation Assays of Antisynthetase Antibodies in Serum Samples from 44 Patients.

Objective To determine the differences between anti-aminoacyl tRNA synthetase (ARS) antibodies among line blots, enzyme-linked immunosorbent assay (ELISA) anti-ARS tests, and RNA-immunoprecipitation (IP) assays. Methods Sera from patients with confirmed or suspected antisynthetase syndrome (ASS) that were positive for either the anti-ARS test or the line-blot assay were used to perform an RNA-IP assay and ELISA to detect individual anti-ARS antibodies. Results Among the 44 patients, 10 were positive only in line-blot assays, 6 were positive only in the anti-ARS test, and 28 were positive in both assays. We compared the accuracy of these assays against the gold standard RNA-IP assay. The κ coefficient was 0.23 in the line-blot assay, but this increased to 0.75 when the cut-off was increased from 1+ to 2+. The κ coefficient was 0.73 in the anti-ARS test. The κ coefficient was 0.85 for positivity in both assays. Patients with ASS that was positive in an RNA-IP assay more frequently had mechanic's hand (62.1% vs. 20%: p=0.031), myositis (51.7 vs. 10%: p=0.028) and more ASS symptoms than those who were positive only in line-blot assays (3.48 vs. 2.2: p=0.019). Conclusions Clinicians need to understand the features of each assay and determine diagnoses by also considering clinical presentations. Diagnoses should not be judged based only on the results of line-blot assays due to the risk of a misdiagnosis from false positives.

Influence of obesity in interstitial lung disease associated with anti-aminoacyl-tRNA synthetase antibodies

BackgroundObesity is a major risk factor for developing various respiratory diseases. Patients with anti-aminoacyl tRNA synthetase (ARS) antibodies often have interstitial lung disease (ILD). The present study was conducted to evaluate the association between obesity and outcomes of anti-ARS antibody-related ILD (ARS-ILD). MethodsWe retrospectively investigated 58 patients with ARS-ILD and compared the clinical characteristics, treatment, and prognoses between obese (body mass index [BMI] ≥25 kg/m2) and nonobese (BMI <25 kg/m2) patients. Chest fat was quantified via computed tomography (CT). Thoracic subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were measured at diagnosis and first relapse of ILD. ResultsSixteen patients were obese. Obese patients had lower percentages of predicted diffusing capacity of the lungs for carbon monoxide and higher high-resolution CT scores and SAT and VAT indexes than did nonobese patients. The ILD relapse rate was higher in obese patients (P < 0.01), especially among those with high SAT indexes (P < 0.01). The SAT and VAT indexes increased significantly from diagnosis until first relapse. Among clinical parameters at first relapse, SAT and VAT indexes were correlated with serum Krebs von den Lungen‐6 levels (r = 0.720, P = 0.008) and total ground-glass attenuation scores (r = 0.620, P = 0.024), respectively. ConclusionsObesity and high SAT indexes are risk factors for ILD relapse in patients positive for anti-ARS antibodies. Evaluating and quantifying patients’ chest fat on CT is important for predicting ILD relapse.

Long-term outcomes and chronological remaining normal lung volumes in patients with interstitial lung disease with anti-aminoacyl tRNA synthetase antibodies and anti-melanoma differentiation-associated gene 5 antibodies

Long-term outcomes and chronological remaining normal lung volumes in patients with interstitial lung disease with anti-aminoacyl tRNA synthetase antibodies and anti-melanoma differentiation-associated gene 5 antibodies

High-Resolution CT Findings of Myositis-Related Interstitial Lung Disease.

Myositis-related interstitial lung disease presents with a wide variety of lesions, ranging from chronic to acute. It can be divided into two main forms by the types of onsets, namely, chronic to subacute type showing nonspecific interstitial pneumonia (NSIP) or NSIP with an organizing pneumonia (OP)/fibrosing OP (FOP) pattern and acute type showing acute lung injury (ALI) to diffuse alveolar damage (DAD) pattern. Anti-aminoacyl tRNA Synthetase antibody-positive cases mainly show an NSIP or FOP pattern, whereas anti-melanoma differentiation-associated gene 5 antibody-positive cases show ALI to DAD pattern. Bilateral consolidation with or without ground-glass opacification with lower lobe predominance is common as a major pattern in all types, but the distribution or extent is sometimes different. The early detection of findings that indicate a rapid progressive course is vital. Diffuse cranio-caudal distribution and multiple ground-glass opacifications with random distribution might indicate a poorer prognosis.

Myositis-Related Interstitial Lung Disease: A Respiratory Physician's Point of View.

Idiopathic inflammatory myositis (IIM) is an umbrella term for diseases of unknown origin that cause muscle inflammation. Dermatomyositis and polymyositis are IIMs that commonly cause interstitial lung disease (ILD). When a patient presents with ILD, the evaluation of whether the case displays the characteristics of myositis should be determined by interview, physical examination, imaging findings, the measurement of myositis-related antibodies, and the determination of disease severity after diagnosis. Rapidly progressing anti-melanoma differentiation-associated gene 5 antibody-positive ILD may require rapid multi-drug therapy, while anti-aminoacyl tRNA synthetase (ARS) antibody-positive ILD can be treated with anti-inflammatory drugs. Importantly, however, anti-ARS antibody-positive ILD often recurs and sometimes develops into fibrosis. Early diagnosis is crucial for treatment, and we therefore need to clarify the features of myositis associated with ILD and suspect these pathologies early. This section reviews what clinicians need to look for and what findings are evaluated in patients when diagnosing myositis associated with ILD.