Interestingly, when comparing the KL-6 levels from COVID-19 cases to a group of patients with ILDs, KL-6 concentrations were significantly higher in ILDs than in the COVID group, thus concluding that KL-6 can be a potential biomarker to assess the severity of ILDs in patients with COVID-19 [26]. This evidence concerns the gene MUC1 and COVID-19.