Periostin Is a Biomarker of Rheumatoid Arthritis-Associated Interstitial Lung Disease

Periostin was investigated as a biomarker for rheumatoid arthritis-associated interstitial lung disease (RA-ILD). This prospective study measured serum monomeric and total periostin, Klebs von den Lungen-6 (KL-6), surfactant protein D (SP-D), and lactate dehydrogenase (LDH) in 19 patients with RA-ILD, 20 RA without ILD, and 137 healthy controls (HC). All biomarkers were higher in RA-ILD than HC or RA without ILD. KL-6 accurately detected ILD in RA patients (area under curve [AUC] = 0.939) and moderately detected SP-D and monomeric and total periostin (AUC = 0.803, =0.767, =0.767, respectively). Monomeric and total periostin were negatively correlated with normal lung area and positively correlated with honeycombing, reticulation, fibrosis score, and the traction bronchiectasis grade but not inflammatory areas. Serum levels of SP-D, KL-6, and LDH did not correlate with the extent of those fibrotic areas on high-resolution CT. Serum monomeric and total periostin were higher in patients with RA-ILD with definite usual interstitial pneumonia pattern compared with other ILD patterns. Immunohistochemical analyses of biopsy or autopsy lung tissues from RA-ILD during the chronic phase and acute exacerbation showed that periostin was expressed in fibroblastic foci but not inflammatory or dense fibrosis lesions. Periostin is a potential biomarker for diagnosis, evaluating fibrosis, and deciding therapeutic strategies for patients with RA-ILD.

Automated summary

This study investigated the potential of Periostin as a biomarker for rheumatoid arthritis-associated interstitial lung disease (RA-ILD). The results showed that all biomarkers were higher in RA-ILD patients compared to healthy controls and RA patients without ILD. KL-6 accurately detected ILD in RA patients, while SP-D and Periostin moderately detected ILD. Periostin levels were correlated with lung fibrosis but not inflammatory areas. Additionally, Periostin was higher in RA-ILD patients with a typical usual interstitial pneumonia pattern. Immunohistochemical analyses showed that Periostin was expressed in fibroblastic foci. These findings suggest that Periostin can be used as a biomarker for diagnosis, evaluating fibrosis, and deciding therapeutic strategies for RA-ILD patients.