The mRNA levels of MMP-12 (P = 0.0067; Figure 3(a)), TIMP-4 (P = 0.0006; Figure 3(b)), and NE (P = 0.0058; Figure 3(c)) in PBMCs of COPD patients were significantly higher than healthy controls. This evidence concerns the gene MMP12 and chronic obstructive pulmonary disease.