Interstitial pneumonia with autoimmune features: A single center prospective follow-up study

Area of Science:

• Pulmonology
• Rheumatology
• Immunology

Background:

• Interstitial pneumonia with autoimmune features (IPAF) is a proposed classification for patients with interstitial lung disease and autoimmune traits who don't meet criteria for specific connective tissue diseases (CTDs).
• Limited data exist on IPAF patients' clinical, serological, and survival characteristics, and their potential progression to CTD.

Purpose of the Study:

• To investigate the demographic, clinical, and serological features of IPAF patients.
• To assess the relationship between these features and patient survival.
• To determine the rate of evolution from IPAF to a defined CTD.

Main Methods:

• Prospective follow-up of 52 IPAF patients for a median of 45 months.
• Periodic assessment of clinical, serological, pulmonary function, and high-resolution CT findings.
• Survival analysis comparing IPAF patients with 104 idiopathic pulmonary fibrosis (IPF) patients.

Main Results:

• The clinical, serological, and morphological domains for IPAF were met by 44, 49, and 29 patients, respectively.
• Seven patients (13.5%) evolved to a definite CTD (4 Sjogren's syndrome, 2 rheumatoid arthritis, 1 polymyositis).
• The estimated 5-year survival for IPAF patients was 69.5%, significantly higher than for IPF patients. Baseline FVC and DLCO were the sole predictors of mortality.

Conclusions:

• IPAF appears to be a distinct clinical entity.
• IPAF demonstrates a low rate of progression to established CTDs.
• Further research is warranted to fully elucidate the clinical course and prognosis of IPAF.