In AE-IPF patients, serum OPN levels were significantly higher than in S-IPF subjects (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (p < 0.001) or healthy controls (. Here, SPP1 is linked to idiopathic pulmonary fibrosis.