Abstract: Cystatin C, cathepsin S, and IL-1 are three important biomarkers of atherosclerosis. Previous studies emphasized the relationship between individual biomarkers in coronary artery disease (CAD) patients and severity of atherosclerostic lesions of the coronary arteries, while combined cystatin C, cathepsin S, and IL-1 have not been reported for clinical classification of CAD. We aimed to establish a link between cystatin C, cathepsin S, IL-1 and CAD in this cohort study. Totally 112 subjects were enrolled and divided into the stable angina pectoris group, the unstable angina pectoris group and the acute myocardial infarction (AMI) groups, and 50 healthy adults served as controls. The levels of the three biomarkers were detected by ELISA. The results showed that serum level of cystatin C (mg/L) was higher in CAD patients compared with those in the healthy controls (AMI vs. unstable angina pectoris vs. stable angina pectoris vs. controls: 1.27_x0001_0.18 vs. 1.09
0.19 vs. 0.91_x0001_0.05 vs. 0.78
0.07, all P < 0.01). Cathepsin S (ng/mL) was also significantly different among the groups (AMI vs. unstable angina pectoris vs. stable angina pectoris vs. controls: 67.30_x0001_8.36 vs. 56.90
7.16 vs. 49.8
2.72 vs. 67.30
8.36, all P < 0.01). IL-1 (pg/mL) was significantly different among the groups as well (AMI vs. unstable angina pectoris vs. stable angina pectoris vs. controls: 2.96
0.57 vs. 2.46
0.24 vs. 2.28
0.09 vs. 2.02
0.13, all P < 0.01). Spearman's correlation test revealed positive correlation between cystatin C, cathepsin S, IL-1 and Gensini score (r = 0.451, 0.491, 0.397, respectively). It is suggested that simultaneous detection of cystatin C, cathepsin S, and IL-1 in serum may be useful in clinical classification and assessment of severity of CAD.