Recent studies have shown that levels of MMPs, especially MMP-9, are elevated in the bronchial alveolar lavage (BAL) fluid from patients with COPD, compared to normal controls [5,7], and high levels of both MMP-9 and its cognate inhibitor TIMP-1 have been found in sputum from chronic bronchitics [8] and correlated with decrease in lung function [9,10]. Here, MMP9 is linked to chronic obstructive pulmonary disease.