TY - JOUR T1 - Interstitial pneumonia with autoimmune features: challenges and controversies JF - European Respiratory Review JO - EUROPEAN RESPIRATORY REVIEW DO - 10.1183/16000617.0177-2021 VL - 30 IS - 162 SP - 210177 AU - John A. Mackintosh AU - Athol U. Wells AU - Vincent Cottin AU - Andrew G. Nicholson AU - Elisabetta A. Renzoni Y1 - 2021/12/31 UR - http://err.ersjournals.com/content/30/162/210177.abstract N2 - The presence of clinical, serological and/or radiological features suggestive, but not confirmatory, of a defined connective tissue disease in patients with interstitial lung disease is a relatively frequent occurrence. In 2015, the European Respiratory Society and the American Thoracic Society proposed classification criteria for the interstitial pneumonia with autoimmune features (IPAF) research entity to capture such patients in a standardised manner, with the intention of nurturing clinical research. This initiative resulted in the publication of several series of IPAF patients, with significant variation between cohorts in clinical characteristics, outcome and the application of IPAF criteria in patient selection. From this increasing body of published work, it has become apparent that revision of IPAF criteria is now required in order to justify the eventual designation of IPAF as a standalone diagnostic term, as opposed to a provisional entity put forward as a basis for clinical research. This review covers the current state of IPAF, conclusions that can and cannot be drawn from the IPAF evidence base, and ongoing uncertainties that require further expert group consideration.Since the proposal of the research entity interstitial pneumonia with autoimmune features (IPAF) in 2015, many questions remain unanswered and challenges remain in its definition https://bit.ly/38GDbLE ER -