Classification criteria for “interstitial pneumonia with autoimmune features”

  1. Presence of an interstitial pneumonia (by HRCT or surgical lung biopsy) and,

  2. Exclusion of alternative aetiologies and,

  3. Does not meet criteria of a defined connective tissue disease and,

  4. At least one feature from at least two of these domains:

    • A. Clinical domain

    • B. Serologic domain

    • C. Morphologic domain

  • A. Clinical domain

    1. Distal digital fissuring (i.e. “mechanic hands”)

    2. Distal digital tip ulceration

    3. Inflammatory arthritis or polyarticular morning joint stiffness ≥60 min

    4. Palmar telangiectasia

    5. Raynaud's phenomenon

    6. Unexplained digital oedema

    7. Unexplained fixed rash on the digital extensor surfaces (Gottron's sign)

  • B. Serologic domain

    1. ANA ≥1:320 titre, diffuse, speckled, homogeneous patterns or

      • a. ANA nucleolar pattern (any titre) or

      • b. ANA centromere pattern (any titre)

    2. Rheumatoid factor ≥2× upper limit of normal

    3. Anti-CCP

    4. Anti-dsDNA

    5. Anti-Ro (SS-A)

    6. Anti-La (SS-B)

    7. Anti-ribonucleoprotein

    8. Anti-Smith

    9. Anti-topoisomerase (Scl-70)

    10. Anti-tRNA synthetase (e.g. Jo-1, PL-7, PL-12; others are: EJ, OJ, KS, Zo, tRS)

    11. Anti-PM-Scl

    12. Anti-MDA-5

  • C. Morphologic domain

    1. Suggestive radiology patterns by HRCT (see text for descriptions):

      • a. NSIP

      • b. OP

      • c. NSIP with OP overlap

      • d. LIP

    2. Histopathology patterns or features by surgical lung biopsy:

      • a. NSIP

      • b. OP

      • c. NSIP with OP overlap

      • d. LIP

      • e. Interstitial lymphoid aggregates with germinal centres

      • f. Diffuse lymphoplasmacytic infiltration (with or without lymphoid follicles)

    3. Multi-compartment involvement (in addition to interstitial pneumonia):

      • a. Unexplained pleural effusion or thickening

      • b. Unexplained pericardial effusion or thickening

      • c. Unexplained intrinsic airways disease# (by PFT, imaging or pathology)

      • d. Unexplained pulmonary vasculopathy

  • HRCT: high-resolution computed tomography; ANA: antinuclear antibody; NSIP: non-specific interstitial pneumonia; OP: organising pneumonia; LIP: lymphoid interstitial pneumonia; PFT: pulmonary function testing. #: includes airflow obstruction, bronchiolitis or bronchiectasis.