Session Type: Abstract Submissions (ACR)
Anti-Jo-1 antibody is detected in the sera of patients with polymyositis/dermatomyositis (PM/DM). The antigen to which this antibody is directed is histidyl-tRNA synthase, an aminoacyl-tRNA synthase (ARS) which occurs in the cytoplasm of eukaryotes, and various anti-ARSs have been identified depending on differences of corresponding amino acids. In addition, other autoantibodies detected in patients with myositis include anti-Ku antibody, anti-Mi-2 antibody, anti-SRP antibody, and anti-PM-Scl antibody. This study was performed to evaluate the clinical characteristics and usefulness of determining the serum levels of these antibodies in patients with connective tissue diseases (CTD) other than PM/DM.
The study included 337 patients with CTD who had been followed up at the outpatient service of this hospital. Of them, 63 had PM/DM, 86 had systemic lupus erythematosus (SLE), 86 had rheumatoid arthritis (RA), 29 had Sjögren’s syndrome (SjS), 11 had mixed connective tissue disease (MCTD), 14 had progressive systemic sclerosis (SSc), 12 had ANCA-associated vasculitis, 5 had Behçet’s disease, 6 had aortitis syndrome, 7 had adult-onset Still’s disease, and 18 had other diseases. Serum levels of antibodies were determined using Myositis Profile 3 Euroline Blot Test Kit commercially available from EUROIMMUN (Lubeck, Germany).Clinical features were assessed for cases found to be positive for these autoantibodies.
The analysis revealed that 12 patients were positive for anti-PL7 antibody, among other anti-ARS antibodies, and 6 of these patients had CTD other than PM/DM. Similarly, anti-PL12 antibody was detected in 4 patients including those with SLE, RA or MCTD. Anti-EJ antibody and anti-Jo-1 antibody were also detected frequently in RA and other non-myositis CTD. As for other myositis-associated autoantibodies, anti-PM-Scl75 antibody was detected in 7 patients with SLE and 2 patients with RA, while anti-Ku antibody was demonstrated in 3 patients with PM/DM, 4 patients with SLE and 3 patients with MCTD.
Regarding the relationship between the autoantibodies detected and clinical manifestations, concurrent interstitial pneumonia (IP) was high in incidence irrespective of underlying disorders among anti-ARS antibody-positive patients with CTD other than PM/DM. Anti-Ku antibody, anti-SRP antibody and anti-Mi-2 antibody, on the other hand, were detected also in non-myositis connective tissue diseases; however, there was no definite correlation between these antibodies and clinical manifestations including IP. The data obtained were reviewed also with respect to arthritis and Raynaud’s phenomenon.
Serum levels of antibodies associated with myositis were determined in 337 patients, and anti-ARS antibodies were detected in a number of patients with CTD other than PM/DM. These autoantibodies detected were strongly correlated with IP, which tended to be intractable. The present results indicate that it is clinically useful to determine the serum levels of anti-ARS antibodies and other myositis-associated autoantibodies in patients with CTD complicated by IP even when their underlying diseases are not myositis.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/clinical-study-of-determination-of-myositis-associated-autoantibodies-in-japanese-patients-with-connective-tissue-diseases-except-autoimmune-myositis/