Table 6.

ERS/ATS criteria for the diagnosis of IPAF

Domain	Characteristics
(A) Clinical	Distal digital fissuring (i.e. ‘mechanic's hands’) Distal digital tip ulceration Inflammatory arthritis or polyarticular morning joint stiffness ≥60 min Palmar telangiectasia Raynaud's phenomenon Unexplained digital oedema Unexplained fixed rash on the digital extensor surfaces (Gottron's sign)
(B) Serological	ANA ≥1:320 titre, diffuse, speckled, homogeneous patterns or ANA nucleolar pattern (any titre) orANA centromere pattern (any titre) RF ≥2 × ULN Anti‐CCP Anti‐dsDNA Anti‐Ro (SS‐A) Anti‐La (SS‐B) Anti‐ribonucleoprotein Anti‐Smith Anti‐topoisomerase (Scl‐70) Anti‐tRNA synthetase (e.g. Jo‐1, PL‐7, PL‐12, others are: EJ, OJ, KS, Zo, YRS) Anti‐PM‐Scl Anti‐CADM (MDA5)
(C) Morphological	(1) Suggestive radiology patterns by HRCT NSIP OP NSIP with OP overlap LIP (2) Histopathology patterns or features by surgical lung biopsy NSIP OP NSIP with OP overlap LIP Interstitial lymphoid aggregates with germinal centres Diffuse lymphoplasmacytic infiltration (with or without lymphoid follicles) (3) Multi‐compartment involvement (not otherwise explained) Pleural effusion or thickening Pericardial effusion or thickening Small airways disease (by PFT, imaging or pathology) Pulmonary vasculopathy

Adapted from Fischer et al., ¹⁸⁰ with permission.

ANA, anti‐nuclear antibody; ATS, American Thoracic Society; CADM, clinically amyopathic dermatomyositis; CCP, cyclic citrullinated peptide; dsDNA, double‐stranded DNA; ERS, European Respiratory Society; HRCT, high‐resolution computed tomography; IPAF, interstitial pneumonia with autoimmune feature; LIP, lymphocytic interstitial pneumonia; NSIP, non‐specific interstitial pneumonia; OP, organizing pneumonia; PFT, pulmonary function test; PM, polymyositis; RF, rheumatoid factor; ULN, upper limit of normal.