A case-control study in Turkey showed that the amounts of MMP-8 in serum, measured using an immunofluorescence assay, were significantly higher in the mild COPD group than in the control group; however, the amounts of MMP-8 and TIMP-1 in serum, measured using an enzyme-linked immunosorbent assay, were similar in both groups. This evidence concerns the gene TIMP1 and chronic obstructive pulmonary disease.