Date: Sunday, November 7, 2021
Session Title: Muscle Biology, Myositis & Myopathies Poster (0683–0722)
Session Type: Poster Session B
Session Time: 8:30AM-10:30AM
Background/Purpose: Many kinds of myositis specific autoantibodies are detected in sera from polymyositis (PM) and dermatomyositis (DM). Screening for autoantibodies is essential in the diagnostic workup of systemic autoimmune rheumatic diseases (SARD). It is noteworthy that recent reports suggest anti- PC4 And SFRS1 Interacting Protein 1 (PSIP1) are more prevalent in healthy individuals compared to SARD, especially systemic lupus erythematosus. However, it is still unclear its significance in PM/DM. Thus, we investigated the frequency of anti-PSIP1 Ab and the clinical features in PM/DM.
Methods: Adult Japanese PM/DM (N=87), SLE (N=17) patients who were treated at Tokai University hospital from 2012 to 2020 and healthy controls/non-SARD (N=41) were enrolled. Anti-ARS, SRP Ab were screened by RNA-immunoprecipitation and anti-MDA5, anti-TIF-1 Ab were detected by immunoprecipitation with [35S]methionine-labeled HeLa cells. anti-PSIP1 Ab and anti-MDA5 Ab titers were measured using enzyme-linked immunoabsorbent assay (ELISA). Clinical data was retrospectively collected.
Results: The frequency of anti-PSIP1 Ab was 27.6% (24/87) in PM/DM, 7.3% (3/41) in healthy controls/non-SARD and 11.8% (2/17) in SLE.
Of note, the prevalence of anti-PSIP1 Ab was significantly higher in PM/DM compared to healthy control/non-SARD and SLE (p < 0.05). The prevalence of anti-PSIP1 Ab in PM/DM patients with anti-ARS, SRP, TIF1-γ and MDA5 Ab were 35.7% (10/28), 11.1% (1/9), 40% (4/10) and 22.5% (9/40), respectively. Among anti-ARS Ab positive PM/DM, none of anti-OJ (0/5) or anti-PL-7 (0/5) were positive for anti-PSIP1, while 66.7% (4/6) of anti-Jo-1 and 50% (6/12) of anti-PL-12 were. In addition, the change of anti-PSIP1 Ab titers were seemed to be correlated with those of anti-MDA5 Ab in the disease course.
Conclusion: In our study, anti-PSIP1 Ab was frequently detected in PM/DM, compared to healthy control/non-SARD and SLE. In addition, measurement of anti-PSIP1 Ab titers may be an indicator of disease activity in DM with anti-MDA5 Ab.
To cite this abstract in AMA style:Hosono Y, Kojima A, Ishii A, Izumi Y, Hirano K, Sasaki N, Yamada C, Sato S. The Clinical Significance of anti-PC4 and SFRS1 Interacting Protein 1 Antibody in Polymyositis and Dermatomyositis Patients [abstract]. Arthritis Rheumatol. 2021; 73 (suppl 10). https://acrabstracts.org/abstract/the-clinical-significance-of-anti-pc4-and-sfrs1-interacting-protein-1-antibody-in-polymyositis-and-dermatomyositis-patients/. Accessed December 3, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-clinical-significance-of-anti-pc4-and-sfrs1-interacting-protein-1-antibody-in-polymyositis-and-dermatomyositis-patients/