Prognostic value of Toll-like receptor 4 on human monocyte subsets combined with computed tomography-adapted Leaman score assessing coronary artery disease

Upregulation of Toll-like receptor 4 (TLR-4) is associated with coronary plaque vulnerability assessed by coronary computed tomography angiography (CCTA). Computed tomography-adapted Leaman score (CT-LeSc) is an independent long-term predictor of cardiac events. The relationship between the TLR-4 expression of CD14(++)CD16(+) monocytes and future cardiac events is unknown. We investigated this relationship using CT-LeSc in patients with coronary artery disease (CAD). METHODS: We analyzed 61 patients with CAD who underwent CCTA. Three monocyte subsets (CD14(++)CD16(−), CD14(++)CD16(+), and CD14(+)CD16(+)) and the expression of TLR-4 were measured by flow cytometry. We divided the patients into two groups according to the best cutoff value of the TLR-4 expression on CD14(+)CD16(+) which could predict future cardiac events. RESULTS: CT-LeSc was significantly greater in the high TLR-4 group than the low TLR-4 group [9.61 (6.70–13.67) vs. 6.34 (4.27–9.09), P < 0.01]. The expression of TLR-4 on CD14(++)CD16(+) monocytes was significantly correlated with CT-LeSc (R(2) = 0.13, P < 0.01). The expression of TLR-4 on CD14(++)CD16(+) monocytes was significantly higher in patients who had future cardiac events than in those who did not [6.8 (4.5–9.1) % vs. 4.2 (2.4–7.6) %, P = 0.04]. High TLR-4 expression on CD14(++)CD16(+) monocytes was an independent predictor for future cardiac events (P = 0.01). CONCLUSION: An increase in the TLR-4 expression on CD14(++)CD16(+) monocytes is related to the development of future cardiac events.