The addition of 1,25D3 to polyI:C-stimulated BSMCs significantly induced CYP24A1 mRNA expression in asthma (5547 ± 454-fold increase, p < 0.001) (Figure 1A) and COPD (3565 ± 311-fold increase, p < 0.01) (Figure 1B) as compared to control groups. This evidence concerns the gene CYP24A1 and chronic obstructive pulmonary disease.