While post-MI plasma IL6 concentrations increased at day 1 and peaked at day 3 in both sexes (Fig. 3b), females had reduced IL6 receptor (IL6R) gene and protein expression in the infarct at day 1 compared to males (p < 0.05; Fig. 2e and Online Fig. 1a). This evidence concerns the gene IL6 and myocardial infarction.