ACR Meeting Abstracts

ACR Meeting Abstracts

Abstract Number: 1343

A Novel Autoantibody Against DNA Damage Binding Protein-1 in Idiopathic Inflammatory Myopathy

Yuji Hosono1,2, Ran Nakashima1, Koji Kitagori1, Kosaku Murakami1, Hajime Yoshifuji1, Koichiro Ohmura3 and Tsuneyo Mimori1, 1Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Kyoto, Japan, 2National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 3Department of Rheumatology and Clinical Immunology, Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Kyoto, Japan

Meeting: 2018 ACR/ARHP Annual Meeting

Keywords: ,

Session Information

Date: Monday, October 22, 2018

Title: Muscle Biology, Myositis and Myopathies Poster II: Basic and Translational Science

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose:

Many kinds of autoantibodies are detected in idiopathic inflammatory myopathy (IIM) patients. Some of them are useful to diagnose, predict the clinical course, and assess therapy in IIM at an early stage. Here we describeand characterize the clinical significance of a novel autoantibody in IIM directed against the DNA damage binding protein1.

Methods:

Three-hundred and eighty patients with various connective tissue diseases (CTDs) and 20 healthy controls (HCs) were screened for autoantibodies by immunoprecipitation with [35S]methionine-labeled HeLa cells. The target autoantigen was immunoaffinity-purified from HeLa cell extracts and was subsequently identified by peptide mass fingerprinting. Antigen specificity of the serum was further examined by immunoblotting.

Results:

An antibody directed against a 120kDa protein was detected in serum from 6 patients with IIM, but not in theserum of other CTD patients or HCs. No patient with anti-120kDa antibodies was positive for other myositis-specific autoantibodies. 50% (3 of 6) were underwent a muscle biopsy compatible with inflammatory myopathy. Most anti-DDB1 positive patients (4 of 6, 67%) showed spontaneous improvements without immunosuppressant treatment. Peptide mass fingerprintingidentified the DNA damage binding protein-1 (DDB1) as the autoantigen recognized by anti-120KDa autoantibodies. Immunoblotting experiments using recombinant full-length DDB1 protein confirmed that this was the autoantigen recognized by the anti-120KDa autoantibodies.

Conclusion:

Anti-DDB1 antibodies are found in mild forms of IIM. Its detection may be helpful for diagnosis and have prognostic and therapeutic implications in patients with IM. This finding may shed new insights into the pathogenesis of IIM.

Disclosure: Y. Hosono, None; R. Nakashima, Medical & Biological Laboratories Co., Ltd., 9; K. Kitagori, None; K. Murakami, None; H. Yoshifuji, None; K. Ohmura, None; T. Mimori, None.

To cite this abstract in AMA style:

Hosono Y, Nakashima R, Kitagori K, Murakami K, Yoshifuji H, Ohmura K, Mimori T. A Novel Autoantibody Against DNA Damage Binding Protein-1 in Idiopathic Inflammatory Myopathy [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/a-novel-autoantibody-against-dna-damage-binding-protein-1-in-idiopathic-inflammatory-myopathy/. Accessed .

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