SFTPD and interstitial lung disease: Figure 2A–C show the correlation between SP-D and coagulation/fibrinolysis markers in patients with AE-ILD. TAT, D-dimer, and PIC levels were significantly positively correlated with SP-D levels. Specifically, TAT and PIC levels showed strong correlations with SP-D levels. No significant correlations were observed between SP-D and other coagulation/fibrinolysis markers. On the other hand, KL-6 showed no correlation with any of the coagulation/fibrinolysis markers (Figure 2D–F).