S100A9 and myocardial infarction: While recent single-cell transcriptomic analysis of primary human megakaryocytes found S100A8 and S100A9 to be differentially expressed in 32 N compared with 4 N megakaryocytes, no increase in these transcripts was seen in megakaryocytes harvested at the time of MI.44 By contrast, however, S100A8/A9 has been shown to be directly released from neutrophils recruited to the necrotic myocardium in acute MI.45,46 The transfer of S100A8 to platelets offers an alternative mechanism for protein enrichment.47