Interstitial pneumonia with autoimmune features (IPAF) is a term used to describe adult patients with interstitial lung disease (ILD) who display some clinical or serological features of autoimmune diseases and who do not meet the full criteria for a specific connective tissue disease (CTD). The aim of this study was to define the demographic, clinical, radiologic, serologic and histopathologic features and assess treatment in children with IPAF.

This retrospective cohort study was conducted at a tertiary referral pediatric pulmonology center between January 2010 and August 2020. Children with proven interstitial pneumonia with no known etiologies were evaluated for IPAF according to European Respiratory Society/American Thoracic Society research statement of IPAF.

Among 132 children with ILD, 17 patients were evaluated in detail for IPAF criteria and six patients were further diagnosed as having IPAF. The incidence of IPAF in our patients with ILD was 4.5%. Four of these patients were female. The median age at the time of ILD diagnosis was 10.5 years. The most common initial symptom was shortness of breath, and the most common physical examination sign was crackles in both lungs. Steroid therapy was given to all patients and four patients received other immunosuppressive agents for steroid sparing. Two of those patients died because of respiratory insufficiency during the follow-up.

Children with interstitial pneumonia and certain clinical, serologic, and/or morphologic features should raise suspicion for the presence of an underlying systemic autoimmune disease. IPAF is also seen in children and should be categorized in chILD classifications.