Clinical, radiologic and serologic profile of patients with interstitial pneumonia with autoimmune features: a cross-sectional study

The current study aimed to characterize patients from a rheumatology referral center in north India, who satisfied the definition of interstitial pneumonia with autoimmune features (IPAF) as given by the American Thoracic Society and European Respiratory Society (ATS/ERS) consensus committee in 2015. Thirty-five adult patients aged 18 years and above, fulfilling the 2015 ATS/ERS criteria for IPAF were included in the study. The clinical and immunological profile, and radiologic findings on high-resolution computerized tomography thorax were noted. Antinuclear antibody (ANA) by indirect immunofluorescence at 1:320 titer and myositis-specific antibody (MSA) assays were performed. Non-parametric tests were used to compare variables between groups. The study cohort included predominantly female patients with a mean age of 50.6 +/- 13 years and mean duration of disease of 38.8 +/- 28.4 months. Majority of patients (49%) fulfilled the morphologic and serologic domains as per the IPAF consensus criteria and 31% patients had features in all three domains. Non-specific interstitial pneumonia was the most common pattern observed in 77% patients. Raynaud's phenomenon and inflammatory arthritis were the predominant autoimmune features. Pulmonary arterial hypertension was documented in 60% of patients on echocardiography. Positive ANA at 1:320 dilution was present in all 26 patients tested, whereas extractable nuclear antigen and MSA assays detected autoantibodies in 49% and 51% of patients respectively. IPAF predominantly affected females in the age group of 50 years and above, with varied autoimmune manifestations and autoantibody profile.

Automated summary

The study found that IPAF mainly affects females over the age of 50, with varied autoimmune manifestations and autoantibody profiles.