Autoimmune-featured interstitial lung disease: a distinct entity

Area of Science:

• Pulmonology
• Rheumatology
• Immunology

Background:

• Interstitial lung disease (ILD) can present with autoimmune features without meeting criteria for connective tissue disease (CTD).
• Prevalence and characteristics of autoimmune-featured ILD (AIF-ILD) remain incompletely understood.
• Distinguishing AIF-ILD from idiopathic pulmonary fibrosis (IPF) and CTD-ILD is crucial for patient management.

Purpose of the Study:

• To determine the prevalence and characteristics of AIF-ILD.
• To compare AIF-ILD with IPF and CTD-ILD.
• To identify factors influencing survival in AIF-ILD.

Main Methods:

• Defined AIF-ILD based on suggestive symptoms and positive serologic tests in ILD patients not meeting CTD criteria.
• Analyzed clinical data, high-resolution CT (HRCT) imaging, and lung biopsy findings.
• Compared AIF-ILD with IPF and CTD-ILD cohorts; evaluated survival using Kaplan-Meier curves.

Main Results:

• AIF-ILD was identified in 32% of subjects, IPF in 29%, and CTD-ILD in 19%.
• A usual interstitial pneumonia (UIP) pattern on HRCT (62%) and histopathology (81%) was common in AIF-ILD.
• Patients with AIF-ILD had survival similar to IPF and worse than CTD-ILD (P < .01); high antinuclear antibody (ANA) titers (≥1:1280) were linked to improved survival (P = .02).

Conclusions:

• Systematic evaluation identifies AIF-ILD, characterized by UIP patterns on imaging and biopsy.
• AIF-ILD exhibits poor survival, comparable to IPF.
• Elevated ANA titers (≥1:1280) may indicate a better prognosis in AIF-ILD.