Prospective nationwide multicentre cohort study of the clinical significance of autoimmune features in idiopathic interstitial pneumonias

Noriyuki Enomoto, Sakae Homma, Naohiko Inase, Yasuhiro Kondoh, Takeshi Saraya, Hajime Takizawa, Yoshikazu Inoue, Hiroshi Ishii, Yoshio Taguchi, Shinyu Izumi, Yasuhiko Yamano, Yoshinori Tanino, Yasuhiko Nishioka, Mikio Toyoshima, Koshi Yokomura, Shiro Imokawa, Naoki Koshimizu, Takehisa Sano, Taisuke Akamatsu, Hiroshi MukaeMotoyasu Kato, Naoki Hamada, Hirofumi Chiba, Shinobu Akagawa, Shigeo Muro, Hironori Uruga, Hiroyuki Matsuda, Yusuke Kaida, Miho Kanai, Kazutaka Mori, Masafumi Masuda, Hironao Hozumi, Tomoyuki Fujisawa, Yutaro Nakamura, Noriyoshi Ogawa, Takafumi Suda

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9 Citations (Scopus)


Background Some patients with idiopathic interstitial pneumonia (IIP) show autoimmune features. Interstitial pneumonia with autoimmune features (IPAF) was recently proposed as a research concept in these patients. However, retrospective studies reported conflicting results of its prognosis. Therefore, this study was conducted to prospectively evaluate the clinical significance of autoimmune features in patients with IIP. Methods This nationwide multicentre study prospectively enrolled consecutive patients with IIP. At the diagnosis, we systematically evaluated 63 features suggestive of connective tissue diseases using a checklist including symptoms/signs and autoantibodies, which contained most items of the IPAF criteria and followed up with the patients. Clinical phenotypes were included in a cluster analysis. Results In 376 patients with IIP enrolled, 70 patients (18.6%) met the IPAF criteria. The proportion of patients with IPAF was significantly lower in idiopathic pulmonary fibrosis (IPF) than in non-IPF (6.0% vs 24.3%, respectively). During a median observation period of 35 months, patients with IPAF more frequently developed systemic autoimmune diseases and had less frequent acute exacerbation of IIPs than patients with non-IPAF. IPAF diagnosis was significantly associated with better survival and was an independent positive prognostic factor in total and patients with non-IPF. Cluster analysis by similarity of clinical phenotypes identified a cluster in which there was a higher number of women, and patients had more autoimmune features and a better prognosis than other clusters. Interpretation These observations suggest that some patients with IIP show autoimmune features with distinct characteristics and favourable prognosis. However, we were not able to determine the appropriate therapies for these patients.

Original languageEnglish
Pages (from-to)143-153
Number of pages11
Issue number2
Publication statusPublished - Feb 1 2022

All Science Journal Classification (ASJC) codes

  • Pulmonary and Respiratory Medicine


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