Circulating Soluble SR-PSOX/CXCL16 as a Biomarker for Acute Coronary Syndrome -Comparison with High-Sensitivity C-Reactive Protein

Aim: Diagnostic values of soluble SR-PSOX/CXCL16 (sSR-PSOX/CXCL16), a receptor for atherogenic oxidized LDL and a membrane-anchored chemokine for CXCR6-positive lymphocytes, for acute coronary syndrome (ACS) were evaluated. Methods: We examined 106 patients undergoing coronary angiography (CAG); 17 patients with ACS and 89 patients without ACS (non-ACS) including stable angina. Circulating sSR-SPOX/CXCL16 was measured in peripheral venous blood by sandwich ELISA. Results: Age, gender, prevalence of diabetes or hypertension, and serum lipid profiles were not significantly different between ACS and non-ACS. Presence or absence of risk factors, such as diabetes, smoking and hypertension, did not significantly affect circulating sSR-PSOX/CXCL16 levels. Circulating sSR-PSOX/CXCL16 levels were significantly lower in ACS than non-ACS (median: 3.05 versus 3.36 ng/mL, p < 0.02). Lipid profiles, high-sensitivity C-reactive protein (hs-CRP), cardiac troponin T (TnT), and soluble LOX-1 (sLOX-1) showed no significant correlation with sSR-PSOX/CXCL16. Receiver-operating characteristic (ROC) curves for ACS detection indicate higher sensitivity and specificity for sSR-PSOX/CXCL16 than hs-CRP In the TnT negative and sLOX-1-negative subpopulation, sSR-PSOX/CXCL16 showed similar sensitivity and specificity for ACS; however, hs-CRP showed less sensitivity and specificity for ACS when compared with the whole population. Conclusion: sSR-PSOX/CXCL16 is a biomarker for ACS, which would provide additional diagnostic information besides TnT and sLOX-1.