MUC1 and interstitial lung disease: More specific markers related to interstitial lung disease (ILD), for example, Krebs von den Lungen-6 (KL-6), which is increased in patients affected by ILD, and Surfactant Protein-A and D (SP-A, SP-D), which reflect the extent of damage to the capillary/alveolar barrier, are under study (21).