Thus, since neutrophils are the primary site of expression of S100A8 and S100A9, and the B6-CF and Bc-CF lungs showed an almost 3-fold increase in neutrophil count, respectively, the elevation of S100A9 in both strains of CF lungs, and in the B6-CF lungs for S100A8, likely corresponds to the increased neutrophil numbers. Here, S100A9 is linked to cystic fibrosis.