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

Figure 3

The correlation of cathepsin S, cystatin C, or cathepsin S/cystatin C with either FEV₁% or LAA score in the AR and COPD groups (). Cathepsin S levels correlated modestly but significantly with FEV₁/FVC (a) and inversely with the LAA score (d) (, ; , , resp.); also cathepsin S/cystatin C ratios correlated modestly but significantly with FEV₁/FVC (c) and inversely with the LAA score (f) (, ; , , resp.). In contrast, cystatin C levels did not correlate with either FEV₁/FVC (b) or LAA (e).

(a)

(b)

(c)

(d)

(e)

(f)