Date: Monday, October 22, 2018
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Background/Purpose: Autoantibodies against the SSA52 Kd protein (anti-SSA52) have been cataloged as myositis-associated antibodies, occurring in up to 30% of cases idiopathic inflammatory myopathies (IIM), commonly with anti-synthetase (AS) antibodies, mainly anti-Jo1. This study sought to describe the association of ILD with the presence of anti-SSA52, including the pattern and severity of interstitial lung disease (ILD) and the correlation of other serological markers co-expressed with anti-SSA52 and ILD.
Methods: We retrospectively identified all anti-SSA52 positive patients evaluated at our center from 2015-2018 for myositis and/or ILD and had myositis-associated autoantibodies tested using a commercial panel (MyoMarker Panel 3®, RDL Reference Laboratories), and collected information on the high-resolution computed tomography (HRCT) pattern, pulmonary function tests (PFT) and serology. The presence of various antibodies were entered into a logistic regression model with ILD as the outcome, using interaction terms based upon univariate analyses.
Results: Our sample included 62 patients positive for anti-SSA52. They most commonly had dermatomyositis/polymyositis (22%), AS syndrome (21%) and systemic sclerosis (9%); 11.3% had non-rheumatic diagnoses. ILD was found in 66% with a HRCT pattern of non-specific interstitial pneumonia (NSIP) in 39%, organizing pneumonia (OP) in 27%, usual interstitial pneumonia (UIP) in 17% and NSPI/OP in 26.8%. Among those with ILD there was concurrent positivity for anti-SSA52 and other antibodies included in the MyoMarker Panel 3, mainly anti-Jo1 (24%), anti-MDA5, anti-TIF1γ and anti-U1RNP (12.2% each). PFT in patients with ILD and anti-SSA52 showed diminished median FVC: 2.12 L (IQR 0.97) and DLCO: 36% (IQR 29). Those positive for both anti-SSA52 and anti-Jo1 had worse function, with median FVC: 1.6 L (IQR 0.89) vs 2.13 L (IQR 0.65) and median DLCO: 26% (IQR 10) vs 44% (IQR 33). No correlation for anti-Jo-1 was found in the multivariable model (β-coefficient 5.55, p= 0.96). Anti-Mi2 (β-coefficient 17.2, p=0.034) and anti-PM-Scl (β-coefficient -17.2, p=0.034) were strongly correlated with ILD, with the latter showing an inverse correlation.
Conclusion: Anti-SSA52 antibody was commonly associated with IIM. NSIP and OP were the most frequent HRCT findings and PFT showed a restrictive pattern with worse FVC and DLCO in those co-expressing anti-SSA52 and anti-Jo1 than those mono-specific for anti-SSA52. In the presence of anti-SSA52 there was a positive correlation of anti-Jo1 and anti-Mi2 with ILD, and anti-PM-Scl seemed to be a protective factor for pulmonary involvement. Additional study of the interaction of autoantibodies with clinical outcomes is underway.
To cite this abstract in AMA style:Calle Botero E, Wang B, Maya JJ, Mira-Avendano I, Abril A. Functional, Radiographic and Serologic Correlates of Anti-SSA52 Kd – Associated Interstitial Lung Disease [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/functional-radiographic-and-serologic-correlates-of-anti-ssa52-kd-associated-interstitial-lung-disease/. Accessed January 23, 2020.
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