Introduction: Recent studies have identified circulating immunoglobulin (Ig) G autoantibodies against cytoplasmic 5'-nucleotidase 1A (cN1A; NT5C1A) in patients with inclusion body myositis (IBM), whose detection provides for an IBM blood diagnostic test. Whether or not anti-cN1A autoantibody isotypes other than IgG are present in IBM has not previously been reported.
Methods: Plasma and serum samples from 205 patients (50 with and155 without IBM) were studied for the presence of IgM and IgA, in addition to IgG, anti-cN1A autoantibodies using immunoblots and enzyme-linked immunoassays (ELISAs).
Results: IgM, IgA, and IgG anti-cN1A autoantibodies were detected by ELISA with similar sensitivities (49-53%) and specificities (94-96%), but with differing patterns of autoantibody isotype presence. Combination assays of all 3 autoantibody levels improved diagnostic sensitivity to 76%.
Conclusions: In addition to previously recognized IgG anti-cN1A autoantibodies, IBM patients have circulating IgM and IgA anti-cN1A autoantibodies. Differing patterns of these isotypes may be present and useful for diagnosis.
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http://dx.doi.org/10.1002/mus.24199 | DOI Listing |
Front Immunol
September 2024
Jiangxi Province Key Laboratory of Immunity and Inflammation, Jiangxi Provincial People's Hospital, Nanchang, China.
Idiopathic inflammatory myopathies (IIMs) encompass a spectrum of autoimmune diseases characterized by muscle inflammation and systemic involvement. This review aimed to synthesize current evidence on the clinical significance and pathogenic mechanisms underlying autoantibodies associated with IIMs. Autoantibodies targeting aminoacyl-tRNA synthetases (ARS) play a pivotal role in antisynthetase syndrome (ASS), highlighting associations with interstitial lung disease (ILD) and distinctive clinical features.
View Article and Find Full Text PDFJ Neurol Sci
September 2024
Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan.
Background: Inclusion body myositis (IBM) is a progressive myopathy occurring in patients over 45 years of age, with heterogeneous and variable clinical features. This study aimed to determine the influence of autoantibodies, gender, and age of onset on the clinical features of IBM.
Methods: Medical records and muscle histology findings of 570 participants with suspected IBM were reviewed.
Biomedicines
July 2023
Rheumatology Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy.
Background: Anti-cytosolic 5'-nucleotidase 1A (anti-cN1A) antibodies were proposed as a biomarker for the diagnosis of inclusion body myositis (IBM), but conflicting specificity and sensitivity evidence limits its use. Our study aimed to assess the diagnostic accuracy of anti-cN1A in a cohort of patients who underwent a myositis line immunoassay for suspected idiopathic inflammatory myopathies (IIM). We also assessed the agreement between two testing procedures: line immunoassay (LIA) and enzyme-linked immunoassay (ELISA).
View Article and Find Full Text PDFJ Neurol Neurosurg Psychiatry
December 2023
Department of Neurology, Tohoku University School of Medicine, Sendai, Miyagi, Japan.
Background: Sporadic inclusion body myositis (sIBM) is an intractable muscle disease that frequently affects elderly people. Autoantibodies recognising cytosolic 5'-nucleotidase 1A (cN1A) were found in the sera of patients with sIBM. However, the pathogenic role of the autoantibodies remained unknown.
View Article and Find Full Text PDFAnn Transl Med
April 2023
Department of Neurology at Peking University First Hospital, Beijing, China.
Objective: To discuss the characteristics of autoantigens, detection methods and roles of myositis associated autoantibodies (MAAs) and myositis specific autoantibodies (MSAs), as well as the clinical features of disease subgroups defined by MAAs/MSAs.
Background: Autoantibodies in patients with idiopathic inflammatory myopathies (IIMs) are conventionally divided into MAAs and MSAs. MAAs usually refer to autoantibodies which are also available in systematic autoimmune diseases (anti-PM/SCL, anti-Ku, anti-Ro52 and anti-U1RNP antibodies).
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