Interstitial Pneumonia with Autoimmune Features: Implications for Clinical Practice

Purpose of Review Interstitial pneumonia with autoimmune features (IPAF) is a research term that was proposed in 2015 to uniformly define patients with an idiopathic interstitial lung disease with subtle features of underlying autoimmunity. In this article, we reviewed studies that utilized IPAF criteria and examined the implications of this classification in clinical practice. Recent Findings There were significant differences in the clinical characteristics and outcomes of the IPAF cohorts suggesting that the interpretation and application of the IPAF criteria are variable. Despite these differences, numerous studies noted that a substantial number of patients with IPAF developed a definite connective tissue disease, and the survival rate for IPAF is likely in-between that of idiopathic pulmonary fibrosis and connective tissue disease-related interstitial lung diseases. Summary Further refinement of the IPAF criteria and larger prospective studies are needed to better understand the implications of IPAF in clinical practice.