Plasma Cathepsin S and Cathepsin S/Cystatin C Ratios Are Potential Biomarkers for COPD

Figure 1

Comparison of plasma levels of cathepsin S (a), cystatin C (b), and cathepsin S/cystatin C (c) between healthy nonsmokers (NS), healthy smokers (HS), subjects at risk (AR), and COPD patients. Distribution of cathepsin S, cystatin C, and cathepsin S/cystatin C among the groups is displayed along with mean ± SD values. Cut points were set at 16.2 ng/mL, 2.1 μg/mL, and , respectively, and displayed as dotted lines, based on the ROC analyses in Figure 2. Mean ± SD is presented. indicates ; versus NS, , , and versus HS.

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