RT Journal Article SR Electronic T1 Elevation of serum napsin A in interstitial lung diseases in comparison with KL-6 and surfactant protein-D JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P732 VO 44 IS Suppl 58 A1 Takuya Samukawa A1 Tsutomu Hamada A1 Tomohiro Kumamoto A1 Masaki Watanabe A1 Keiko Mizuno A1 Ikkou Higashimoto A1 Hiromasa Inoue YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P732.abstract AB Napsin A is an aspartic proteinase with a molecular weight of approximately 38 kDa, which is expressed in normal lung parenchyma in type II pneumocytes, and we have shown that napsin A was founded high concentration in serum of patients with idiopathic pulmonary fibrosis (IPF). However, napsin A has not been tested as a marker for other forms of interstitial lung diseases (ILDs).The aim of this study was to investigate the potential of serum napsin A as a marker in various forms of ILD in comparison with KL-6 and surfactant protein-D (SP-D).Subjects consisted of 32 patients with chronic fibrosing interstitial pneumonia (CFIP) including 20 with IPF and 12 with nonspecific interstitial pneumonia (NSIP), 34 with ILD associated connective tissue disease (CTD-ILD), 11 with hypersensitivity pneumonia (HP), 5 with pulmonary alveolar proteinosis (PAP), 20 with bacterial pneumonia, and 20 healthy volunteers. Each serum levels of napsin A, KL-6, and SP-D were measured by commercially available ELISA kits.The serum napsin A levels were significantly (p<0.01) higher in patients with IPF (169.1 ± 97.1 ng/ml), NSIP (178.4 ± 221.5 ng/ml), CTD-ILD (109.0 ± 156.3 ng/ml), HP (333.1 ± 62.8 ng/ml), and PAP (500.1± 239.6 ng/ml) than those in bacterial pneumonia (38.6 ± 37.4 ng/ml) and healthy volunteers (28.9 ± 21.2 ng/ml). KL-6 and SP-D levels were also significantly higher in ILD patients than in bacterial pneumonia and healthy volunteers (p<0.01), and serum napsin A levels correlated with those of KL-6 and SP-D in patients with ILDs.Our findings shows serum napsin A may be useful biomarker for ILDs.