Antibodies against Ro52 in idiopathic inflammatory myopathies are associated with objective sicca symptoms.

Autoantibodies against Ro52 are not only detected in Sjögren's disease (SjD), but also in idiopathic inflammatory myopathies, where they correlate with the incidence and severity of interstitial lung disease (ILD). It is still unclear whether antibodies against Ro52 are associated with further clinical manifestations in idiopathic inflammatory myopathies, as reduced tear and saliva production as a sign of associated SjD. Thus, this study aimed to determine the prevalence of objective SjD signs in Ro52-positive patients with idiopathic inflammatory myopathies, as well as the prevalence, characteristics, and clinical associations of ILD. A retrospective data analysis of patients from the Departments for Rheumatology, Nephrology, Neurology and Respiratory Medicine at Hannover Medical School, Germany was performed, in which a myositis immunoblot was determined between 2018 and 2024. Out of these patients, a total of 97 patients who were diagnosed with idiopathic inflammatory myopathy were included in the analysis. Overall, antibodies against Ro52 were detected in the myositis immunoblot in 46 of 97 patients (47%), whereas SSA antibodies were only detectable in 37 of 91 patients (41%) in the ELISA test. The detection of anti-Ro52 antibodies was associated with ILD (OR 3.5; p = 0.004). In addition, the presence of anti-Ro52 antibodies correlated with objective sicca symptoms, detected by reduced saliva and/or tear production in the Saxon or Schirmer test (OR 6.3; p=0.026). This study revealed in patients with idiopathic inflammatory myopathies, anti-Ro52 antibodies are associated both with the occurrence of interstitial lung disease and with reduced saliva and tear production. Thus, they mark associated SjD in idiopathic inflammatory myopathy patients.