This observation solidifies the detrimental role of S100a9+Ly6c+ C6 cells in the cardiac repair process after MI, further supporting the possibility that the beneficial effect of CXCR2 blockade on cardiac repair is more likely due to the decreased generation of S100a9+Ly6c+ C6 cells rather than reduced neutrophil recruitment. This evidence concerns the gene S100A9 and myocardial infarction.