Interstitial pneumonia with autoimmune features: A case series and overview.

The topic of interstitial pneumonia with autoimmune features (IPAF) is a research classification proposed by the European Respiratory Society/American Thoracic Society Task Force: this includes patients with idiopathic interstitial pneumonia (IIP) and clinical features, suggesting an underlying autoimmune process, but who do not meet established criteria for a connective tissue disease (CTD). We aimed to perform a detailed characterization of clinical, serological, and radiological features for our patients with IPAF criteria. Six patients were included, and a comprehensive description of these cases revealed a heterogeneous group in terms of clinical and treatment options. In most patients, it was possible to identify other features and disorders with an autoimmune "background," which may support the inclusion of these patients in the IPAF classification. No deaths or significant decline in lung function occurred, and thus no definitive diagnosis of CTD could be found over 35 months of median follow-up. Therefore, IPAF is a recent concept, with many questions still open in regard to its usage in the ILD field.