Anti-aminoacyl tRNA Synthetase Antibodies 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.

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.

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.

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.

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.

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

Management of Myositis-Associated Interstitial Lung Disease.

Idiopathic inflammatory myopathies, including polymyositis (PM), dermatomyositis (DM), and clinically amyopathic DM (CADM), are a diverse group of autoimmune diseases characterized by muscular involvement and extramuscular manifestations. Interstitial lung disease (ILD) has major pulmonary involvement and is associated with increased mortality in PM/DM/CADM. The management of PM-/DM-/CADM-associated ILD (PM/DM/CADM-ILD) requires careful evaluation of the disease severity and clinical subtype, including the ILD forms (acute/subacute or chronic), because of the substantial heterogeneity of their clinical courses. Recent studies have highlighted the importance of myositis-specific autoantibodies’ status, especially anti-melanoma differentiation-associated gene 5 (MDA5) and anti-aminoacyl tRNA synthetase (ARS) antibodies, in order to evaluate the clinical phenotypes and treatment of choice for PM/DM/CADM-ILD. Because the presence of the anti-MDA5 antibody is a strong predictor of a worse prognosis, combination treatment with glucocorticoids (GCs) and calcineurin inhibitors (CNIs; tacrolimus (TAC) or cyclosporin A (CsA)) is recommended for patients with anti-MDA5 antibody-positive DM/CADM-ILD. Rapidly progressive DM/CADM-ILD with the anti-MDA5 antibody is the most intractable condition, which requires immediate combined immunosuppressive therapy with GCs, CNIs, and intravenous cyclophosphamide. Additional salvage therapies (rituximab, tofacitinib, and plasma exchange) should be considered for patients with refractory ILD. Patients with anti-ARS antibody-positive ILD respond better to GC treatment, but with frequent recurrence; thus, GCs plus immunosuppressants (TAC, CsA, azathioprine, and mycophenolate mofetil) are often needed in order to achieve favorable long-term disease control. PM/DM/CADM-ILD management is still a therapeutic challenge for clinicians, as evidence-based guidelines do not exist to help with management decisions. A few prospective clinical trials have been recently reported regarding the treatment of PM/DM/CADM-ILD. Here, the current knowledge on the pharmacologic managements of PM/DM/CADM-ILD was mainly reviewed.

The comparison of nailfold videocapillaroscopy findings between anti-melanoma differentiation-associated gene 5 antibody and anti-aminoacyl tRNA synthetase antibody in patients with dermatomyositis complicated by interstitial lung disease

Dermatomyositis (DM) is frequently complicated by interstitial lung disease (ILD), which increases mortality. This study aims to elucidate the clinical significance of nailfold videocapillaroscopy (NVC) on assessing the disease activity and prognosis of DM-ILD. We compared the NVC findings between anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody-positive and anti-aminoacyl tRNA synthetase (anti-ARS) antibody-positive patients, the survival and ILD-related death groups, and examined the association of NVC findings with prognostic factors of DM-ILD. The median scores of microhemorrhage and capillary disorganization in the anti-MDA5 antibody-positive group were significantly higher than those in the anti-ARS antibody-positive group (P = 0.012 and 0.044, respectively). In contrast, the median scores of tortuous capillaries in the anti-ARS antibody-positive group were significantly higher than those in the anti-MDA5 antibody-positive group (P = 0.002). The median scores of microhemorrhage was significantly higher in the ILD-related death group than the survival group (P = 0.02). The scores of microhemorrhage, capillary disorganization, and neoangiogenesis correlated with known poor prognosis factors of DM-ILD. Additionally, the scores of microhemorrhage and capillary loss correlated significantly with the total fibrosis scores of chest high-resolution computed tomography. These findings suggest that NVC is a useful tool for assessing the disease activity and prognosis of DM-ILD.

Influence of Antisynthetase Antibodies Specificities on Antisynthetase Syndrome Clinical Spectrum Time Course.

Antisynthetase syndrome (ASSD) is a rare clinical condition that is characterized by the occurrence of a classic clinical triad, encompassing myositis, arthritis, and interstitial lung disease (ILD), along with specific autoantibodies that are addressed to different aminoacyl tRNA synthetases (ARS). Until now, it has been unknown whether the presence of a different ARS might affect the clinical presentation, evolution, and outcome of ASSD. In this study, we retrospectively recorded the time of onset, characteristics, clustering of triad findings, and survival of 828 ASSD patients (593 anti-Jo1, 95 anti-PL7, 84 anti-PL12, 38 anti-EJ, and 18 anti-OJ), referring to AENEAS (American and European NEtwork of Antisynthetase Syndrome) collaborative group’s cohort. Comparisons were performed first between all ARS cases and then, in the case of significance, while using anti-Jo1 positive patients as the reference group. The characteristics of triad findings were similar and the onset mainly began with a single triad finding in all groups despite some differences in overall prevalence. The “ex-novo” occurrence of triad findings was only reduced in the anti-PL12-positive cohort, however, it occurred in a clinically relevant percentage of patients (30%). Moreover, survival was not influenced by the underlying anti-aminoacyl tRNA synthetase antibodies’ positivity, which confirmed that antisynthetase syndrome is a heterogeneous condition and that antibody specificity only partially influences the clinical presentation and evolution of this condition.

Elevated serum B-cell activating factor levels in patients with dermatomyositis: Association with interstitial lung disease.

Patients with dermatomyositis (DM) frequently have myositis-specific autoantibodies (MSA), which are closely associated with different clinical features. Patients with anti-aminoacyl-tRNA synthetase antibody (ARS-Ab) and anti-melanoma differentiation-associated gene 5 (MDA5)-Ab often have interstitial lung disease (ILD). Recently, anti-MDA5-Ab levels have been shown to correlate with disease activity in DM patients. Thus, B cells that are stimulated by excess B-cell activating factor (BAFF) play an important role in the pathogenesis of DM through auto-Ab production. In this study, we investigated the role of BAFF in DM patients. We measured the serum BAFF levels in 56 adult DM patients (14 with anti-ARS-Ab, 18 with anti-MDA5-Ab, seven with anti-Mi-2-Ab and 17 with anti-transcriptional intermediary factor-1γ-Ab) . For a longitudinal study, 130 serum specimens from 10 DM patients with anti-MDA5-Ab were analyzed. Serum BAFF levels were significantly higher in DM patients than in healthy controls. DM patients with elevated serum BAFF levels more frequently had ILD. In subgroup analysis, DM patients with anti-ARS-Ab and DM patients with anti-MDA5-Ab exhibited increased BAFF levels compared with controls, while DM patients with other MSA showed BAFF levels comparable with controls. In the longitudinal study, serum BAFF levels in DM patients with anti-MDA5-Ab were decreased after immunosuppressive therapy along with serum levels of anti-MDA5-Ab and ferritin, which are biomarkers of disease activity. These results suggest that BAFF plays an important role in the pathogenesis of ILD in DM patients with anti-ARS and anti-MDA5-Ab. Furthermore, serum BAFF level is associated with disease activity in DM patients with anti-MDA5-Ab.

Autoantibodies in idiopathic inflammatory myopathies: Clinical associations and laboratory evaluation by mono- and multispecific immunoassays.

Idiopathic inflammatory myopathies (IIM) are a group of diseases characterized by immune-mediated muscular lesions that may be associated with extra-muscular manifestations involving skin, lungs, heart or joints. Four main groups of IIM can be distinguished: dermatomyositis (DM), overlap myositis including mainly anti-synthetase syndrome (ASS), immune mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM). Myositis-specific autoantibodies (MSA) are increasingly recognized as valuable tools for diagnosis, classification and prognosis of IIM. For example, ASS is associated with anti-aminoacyl tRNA synthetase antibodies (anti-Jo-1, PL-7, PL-12, …), IMNM with anti-SRP and anti-HMGCR; IBM with anti-cytosolic 5'nucleotidase 1A (cN1A), and DM with anti-Mi-2, anti-MDA-5, anti-TIF-1γ, anti-NXP-2 and anti-SAE. Moreover, anti-MDA-5 is associated with amyopathic myositis and interstitial lung disease and anti-TIF-1γ and anti-NXP-2 with juvenile DM as well as malignancy in patients >40 years. Most MSA have initially been discovered by immunoprecipitation. In routine laboratories, however, MSA are screened for by indirect immunofluorescence and identified by (automated) monospecific immunoassays or by multispecific immunoassays (mainly line/dot immunoassays). Validation of these (multispecific) assays is a challenge as the antibodies are rare and the assays diverse. In this review, we give an overview of the (clinical) performance characteristics of monospecific assays as well as of multispecific assays for detection of MSA. Although most assays are clinically useful, there are differences between techniques and between manufacturers. We discuss that efforts are needed to harmonize and standardize detection of MSA.

Clinical characteristics and outcome in patients with antisynthetase syndrome associated interstitial lung disease: a retrospective cohort study

ABSTRACTBackground and objective: To describe the clinical characteristics including the bronchoalveolar lavage fluid (BALF) characteristics of patients with antisynthetase syndrome (AS) associated interstitial lung disease (ILD) in a tertiary ILD outpatient clinic, their medical therapy and outcome.Methods: Retrospective cohort study of patients with AS-ILD. All available data of clinical characteristics, pulmonary function tests, laboratory parameters, BALF analysis, histology, high-resolution computed tomography (HRCT) and treatment were collected from the patient files.Results and conclusions: Twelve patients with AS-ILD were identified. Mean age at diagnosis was 55 years (range 45–69), 67% were female. Mean follow-up time was 7 years. The anti-aminoacyl tRNA-synthetase antibodies presented were anti-Jo1 (n = 6), anti-PL7 (n = 3), anti-PL12 (n = 2) and anti-EJ (n = 1). HRCT patterns were mainly non-specific interstitial pneumonia (75%). Four patients had BALF-eosinophilia (two of four anti-Jo1 patients) and two anti-PL12 positive patients had BALF-neutrophilia. Two AS-ILD patients improved on rituximab (RTX) as induction treatment and three out of four patients were stabilised on RTX as maintenance treatment. Two patient obtained remission by cyclophosphamide. Four patients were stabilised on azathioprine alone or in combination with oral corticosteroids.Our cohort of AS-ILD patients showed clinical characteristics in accordance with previous reports at baseline and was comparable to other cohorts. Most patients can be stabilised with immunosuppressive treatment.

019 Distinct clinicopathologic and radiological manifestations of the skin, lung, and muscle diseases in patients with dermatomyositis positive for anti-aminoacyl tRNA synthetase antibodies

019 Distinct clinicopathologic and radiological manifestations of the skin, lung, and muscle diseases in patients with dermatomyositis positive for anti-aminoacyl tRNA synthetase antibodies

Clinical Heterogeneity of Interstitial Lung Disease in Polymyositis and Dermatomyositis Patients With or Without Specific Autoantibodies

BackgroundThe aim of this study was to compare the heterogeneity of interstitial lung disease (ILD) in patients with polymyositis and dermatomyositis (PM/DM) according to serological type. MethodsA total of 182 patients with PM/DM-ILD were observed retrospectively. Antiaminoacyl-tRNA synthetase (ARS) and antimelanoma differentiation-associated gene5 (MDA5) antibodies were screened using immunoblotting approach. The patients with ILD were divided into 3 groups: MDA5 (with anti-MDA5 antibody), ARS (with anti-ARS antibody) and MSN (without anti-MDA5 or anti-ARS antibody) group. Pulmonary features, treatment responses and prognoses were compared among the groups. ResultsA higher percentage of rapidly progressive ILD (RP-ILD) occurrences (55.8% versus 25% versus 16.9%, P < 0.001) was observed in the MDA5 group compared to ARS and MSN groups. The MSN group experienced lower dyspnea (48.2% versus 79% versus 71.4%, P = 0.001) and fever (18.1% versus 39.5% versus 37.5%, P = 0.01) frequencies compared to MDA5 and ARS groups. Response to 6-month treatment among 95 patients showed highest deterioration ratio (70%, P = 0.001) of ILD in the MDA5 group. Additionally, the highest frequency of ILD improvement (60%, P = 0.04) was observed in the ARS group. During the observation period, 24 patients died of respiratory failure. The 5-year survival rates were significantly lower in MDA5 group (50.2%) compared to ARS group (97.7%) or the MSN group (91.4%) (P < 0.001). ConclusionsMDA5-ILD was associated with severe pulmonary manifestations, poor response to treatment and aggravated prognosis. The ARS-ILD group had favorable treatment response and prognosis. MSN-ILD patients had relatively worse treatment response and prognosis compared to the ARS group, even though they expressed milder pulmonary manifestation.

Interstitial lung disease-associated antisynthetase syndrome

Interstitial lung disease (ILD) is one of the major extramuscular manifestations of polymyositis (PM) and dermatomyositis (DM). Presentation of PM and DM with ILD is not uncommon, but its clinical and radiological features can be similar to other conditions and can be challenging to diagnose. The presence of anti-aminoacyl tRNA synthetase antibodies in the presence of ILD is diagnostic of antisynthetase syndrome. A delayed diagnosis can be associated with the progression of pulmonary involvement and potentially increased morbidity. Timely diagnosis leads to appropriable lifesaving treatment. We report on a patient with chronic respiratory symptoms who had positive anti-Jo-1 antibodies and presented in respiratory failure, requiring non-invasive ventilation.