Interstitial pneumonia with autoimmune features: a critical appraisal of the new definition

We review the newly formulated and published research classification criteria for interstitial pneumonia with autoimmune features and appraise these criteria in light of findings from recent investigations.

Previous studies demonstrated that interstitial pneumonia may be caused by an autoimmune process with a variety of names and criteria utilized for this entity. To standardize terminology and provide a definition for future research, a multidisciplinary task force formulated criteria by which patients with interstitial lung disease and autoimmune features might be recognized. The interstitial pneumonia with autoimmune features criteria require the presence of an interstitial pneumonia on chest imaging or surgical lung biopsy, exclusion of an alternate cause, the absence of a defined connective tissue disease and at least one feature suggestive of autoimmunity from at least two of three domains: clinical with specific extra-thoracic features, serologic with positive autoantibodies and morphologic as demonstrated by chest imaging, histopathology, or multicompartment involvement. Although recent studies provide insight into features of significance, these criteria have not undergone formal validation.

A uniform name and set of research criteria for interstitial pneumonia with autoimmune features may identify patients with treatment responsive interstitial lung disease and an improved prognosis. These criteria require validation before they can be applied in the clinical setting.