CD28 and angina unstable: CD4.0 and CD4.1 exerted a cytotoxic gene expression profile exemplified by expression of GZMA, GZMK, and PRF1. Apart from these cytotoxic transcripts, cells in CD4.0 also showed very little CD28 expression and some GZMB expression, suggesting that these cells are cytotoxic CD4+CD28null cells that have previously been correlated with unstable angina and increased risk of Major Adverse Cardiovascular Events.30,31 In addition, gene expression in this cluster confirmed an enrichment in proinflammatory pathways associated with adaptive immune responses (Figure 3D).