Autoimmune-featured interstitial lung disease: A distinct entity

Abstract

Background: Patients with interstitial lung disease (ILD) may have features of an autoimmune disorder that do not meet the diagnostic criteria for connective tissue diseases. We determined the prevalence and characteristics of autoimmune-featured ILD(AIF-ILD) and compared these with those of idiopathic pulmonary fibrosis (IPF) and known connective tissue disease-related ILD (CTD-ILD). Methods: Patients with ILD who did not meet the criteria for a connective tissue disease were defined as having AIF-ILD if they had a sign or symptom suggestive of a connective tissue disease and a serologic test reflective of an autoimmune process. Clinical characteristics, high-resolution CT images, and lung biopsy specimens were analyzed and compared with those of patients with IPF and CTD-ILD. Survival was evaluated using a Kaplan-Meier curve. Results: Two hundred subjects completed the questionnaire and serologic testing. AIF-ILD was identified in 32%, IPF in 29%, and CTD-ILD in 19%. Gender, age, and race differed among groups (P