IL21 and coronary artery disorder: When CAD patients’ NK cells were stimulated by IL-2, IL-12, IL-15, IL-18, or IL-21, the R-PrI >1 group and the R-PrI <1 group had no statistic difference in the serum CK level (Figure 3A), CK-MB level (Figure 3B), BNP level (Figure 3C) and cTnI level (Figure 3D).