Association between autoantibodies and interstitial lung disease in autoimmune disease patients: a retrospective study.

This study aimed to investigate the relationship between specific autoantibodies, particularly anti-Ro52, and the development of interstitial lung disease (ILD) in patients with autoimmune diseases (AID), with the goal of identifying potential biomarkers for the early detection and management of ILD. A retrospective cohort study was conducted at Peking Union Medical College Hospital, involving 2,021 AID patients who underwent antinuclear antibody (ANA) testing between 2017 and 2019. Clinical and serological data were collected to assess the presence of ILD and its association with specific autoantibodies. Least absolute shrinkage and selection operator (LASSO) regression was used to identify predictors of ILD. Among the 2,021 patients, ILD prevalence varied across AID subgroups, with the highest rates observed in idiopathic inflammatory myopathies (IIM), overlap syndrome, and systemic sclerosis. Anti-Ro52 was significantly more frequent in IIM patients with ILD compared to those without ILD (83.0% vs. 37.8%, p<0.0001). Anti-RNP was detected at a significantly higher rate in lupus-ILD patients. Additionally, positivity rates of anti-SSA/Ro60 and anti-CENP B were inversely associated with ILD in Sjögren's disease and systemic sclerosis, respectively. LASSO regression analysis identified anti-Ro52, age, and anti-MDA5 as significant predictors of ILD development in IIM. Anti-Ro52 positivity was associated with a more than two-fold increased risk of ILD progression in mixed connective tissue disease. Anti-Ro52, together with age and anti-MDA5, was identified as a significant predictor of ILD in IIM patients. This study highlights the potential of autoantibodies as biomarkers for early detection and management of ILD in AID patients.