Session Type: Poster Session (Sunday)
Session Time: 9:00AM-11:00AM
Background/Purpose: Objective:To determine the frequency and staining patterns of antinuclear antibodies (ANA) in myositis patients who do not have known myositis-specific autoantibodies.
Methods: Material and methods:Sera from dermatomyositis (DM), inclusion body myositis (IBM), and polymyositis (PM)patients without known myositis-specific autoantibodies, as well as serum from healthy control patients, were tested for ANA by indirect immunofluorescence (IIF) assay on HEp-2 cells. In sera from ANA-positive patients and controls, the pattern of positivity was classified according to the International Consensus on ANA Patterns (ICAP). The prevalence and pattern of ANA in different myositis subgroups was compared to those of healthy sera.
Results: Results:Sera from189 myositis-specific autoantibody-negative myositis patients (76 DM, 50 IBM and 63 PM) and 91 healthy comparators were included in the study. Most DM sera were moderately or strongly ANA positive (53%, p< 0.001). Only 33%, 22%, and 15% were moderately or strongly ANA positive in the PM, IBM, and healthy control groups, respectively (all p >0.05). ANA positivity was mostly nuclear (as opposed to cytoplasmic or mitotic) and the most common pattern was fine speckled. The only difference in ANA pattern among myositis subgroups was a higher prevalence of a nuclear fine speckled pattern in DM patients (61%, p=0.02).
Conclusion: Conclusions:Most myositis-specific autoantibody-negative DM patients have moderate/strong ANA positivity, predominantly in a fine speckled pattern. In contrast, myositis-specific autoantibody-negative PM and IBM patients show similar rates of ANA positivity as healthy controls. These findings suggest that currently ANA-positive unidentified autoantibodies are more likely to exist in DM patients than in IBM or PM.
To cite this abstract in AMA style:casal-Dominguez M, Pinal-Fernandez I, Marin A, Sanz-Martinez M, Baucells-de la Pena A, Pak K, Hosono Y, Christopher-Stine L, Mammen A. Frequency and Staining Patterns of Antinuclear Antibodies in Myositis Patients Without Known Myositis-specific Autoantibodies [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/frequency-and-staining-patterns-of-antinuclear-antibodies-in-myositis-patients-without-known-myositis-specific-autoantibodies/. Accessed April 13, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/frequency-and-staining-patterns-of-antinuclear-antibodies-in-myositis-patients-without-known-myositis-specific-autoantibodies/