Interstitial pneumonia with autoimmune features: Clinical, radiologic, and histological characteristics and outcome in a series of 57 patients.

Background: Interstitial pneumonia with autoimmune features (IPAF) has recently been defined by an international Taskforce to characterize interstitial lung disease associated with systemic manifestations limited to subtle serological and clinical autoimmune abnormalities and not fulfilling the international criteria for the diagnosis of a given connective tissue disease.

Objective: to report on a series of patients with IPAF, and to compare their outcome to that of a cohort of patients with idiopathic pulmonary fibrosis (IPF).

Methods: Retrospective analysis of consecutive patients in a single institution over a 3-year period.

Results: Out of 778 consecutive patients with interstitial lung disease, 55% had idiopathic interstitial pneumonia (including 20.1% with IPF), 21.5% had connective tissue disease, and 7.3% had IPAF. Patients (49% of females) had a mean FVC of 64% and a mean DLco of 49%. Serologic criteria for IPAF were the most frequent (93%), followed by "morphologic" criteria (79%), and clinical criteria (47%). Fifty three percent of patients had a NSIP pattern on CT. Nailfold capillaroscopy found giant capillaries in 13/30 patients tested (23%). No significant was found in overall survival between patients with IPAF and those with IPF.

Conclusion: The recently defined criteria for IPAF are fulfilled by a significant proportion of patients referred for interstitial lung disease. As compared to those with IPF, patients with IPAF are more frequently females, have distinctive characteristics, have relatively frequent abnormalities at nailfold capillaroscopy, with no difference in age or in overall survival. Prospective studies are needed to guide the management of IPAF.