Systemic autoimmune rheumatic diseases-associated interstitial lung disease: a pulmonologist's perspective

Connective tissue disease (CTD)-associated interstitial lung disease (ILD) is a complex condition arising in various autoimmune disorders, such as systemic sclerosis, Sjögren disease, systemic lupus erythematosus and idiopathic inflammatory myopathies. The broader term of systemic autoimmune rheumatic diseases (SARDs) and SARD-ILD are increasingly adopted in various guidelines to allow inclusion of other rheumatic diseases such as rheumatoid arthritis. SARD-ILD significantly impacts morbidity and mortality, with disease manifestations ranging from mild to severe and life-threatening. Epidemiological data show varying ILD prevalence rates amongst SARDs, with fibrosis being a key pathological component secondary to immune-mediated inflammation and tissue remodelling. SARD-ILD presents diverse histological patterns, primarily nonspecific interstitial pneumonia and usual interstitial pneumonia, each informing prognosis and guiding therapeutic strategies. Diagnosis relies on a comprehensive evaluation of clinical, serological, radiological and histological data, involving a multidisciplinary team. Immunosuppressive therapy is the cornerstone of treatment, with concurrent use of anti-fibrotic agents in specific progressive cases. Disease management is stratified by severity, with distinct guidelines for stable, progressive and rapidly progressive ILD. The prognosis varies across SARD-ILD types, influenced by specific markers, imaging features, and response to therapy. In severe cases, lung transplantation may be considered. Early recognition remains critical in optimising outcomes for SARD-ILD patients.