SFTPB and interstitial lung disease: Furthermore, high levels of SFTPB in serum EVs were significantly associated with mortality (HR 2.67; 95%CI 1.08–6.58; P = 0.0067 by log-rank test) (Figure 4D), and stratified Cox proportional hazards analysis by ILD-GAP index indicated a similar trend (HR 4.37; 95%CI 0.89–21.35; P = 0.069).