MPO and rheumatoid arthritis: The types of AD related to ILD were grouped as follows: SSc (n = 7), IIM (n = 6; five with anti-synthetase syndrome and one with amyopathic dermatomyositis), RA (n = 5), interstitial pneumonia with autoimmune features (IPAF) (n = 3), primary Sjögren’s syndrome (n = 3) and myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) positive (n = 2).