Clinical Characteristics and Prognostic Value of Ro52/SSA Antibodies in Idiopathic Inflammatory Myopathies

Abstract

Background/purpose: Anti-Ro52 are myositis-associated antibodies found in idiopathic inflammatory myopathies (IIMs). This chart review aims to evaluate the frequency, significance, and associated clinical characteristics of Ro52/SSA positivity in IIM patients.

Methods: We performed a chart review of IIM patients diagnosed between January 2006 and December 2020. All patients met either the 1975 Bohan and Peter or the European League Against Rheumatism/American College of Rheumatology classification criteria for probable or definite myositis. Demographics, clinical and serologic parameters, treatments, and outcomes were compared in patients with anti-Ro52/SSA antibodies and patients without anti-Ro52/SSA antibodies.

Results: One hundred eighty-nine patients with IIM were tested for either Ro52 or SSA, with 45 positive for Ro52/SSA (23.8%). Patients with IIM and Ro52/SSA+ were younger at age at onset of disease (44.8 vs. 51.2 years, p = 0.008). Ro52/SSA+ was more common in antisynthetase syndrome (p < 0.001; odds ratio [OR], 4.44; 95% confidence interval [CI], 2.11-9.33) and not frequently identified in clinically amyopathic dermatomyositis (CADM) (p = 0.02; OR, 0.13; 95% CI, 0.02-0.96) or immune-mediated necrotizing myopathy (p = 0.003; OR, 0.14; 95% CI, 0.03-0.63). Of the extraskeletal muscle manifestations, interstitial lung disease (ILD) was strongly associated with Ro52/SSA+ (p < 0.001; OR, 6.61; 95% CI, 3.15-13.86), as was dysphagia (p = 0.006; OR, 2.73; 95% CI, 1.31-5.71). Interstitial lung disease pattern and pulmonary function testing impairment did not differ based on antibody status. There was no significant difference in outcomes between groups.

Conclusion: In this myositis cohort, Ro52/SSA+ was present in nearly one-fourth of the population and had a strong association with the antisynthetase syndrome subtype, ILD, and dysphagia. Although these disease manifestations are associated with significant morbidity, in our cohort, they were not associated with increased mortality or more severe ILD.