MMP9 and cystic fibrosis: Figure 5B demonstrates that even when MMP-9 is controlled for by MPO, there is a notable correlation between Ac-PGP levels and MMP-9. These results demonstrate a strong correlation (r = 0.63, p = 0.017) in CF clinical samples between concentration of Ac-PGP and the level of MMP-9, recapitulating with fidelity our ex vivo and in vitro data.