CD28 and myocardial infarction: In the context of immune activators, the expression levels of CD27, CD28, CD40, CD40 LG, CD70, ICOSLG, KLRK1, LTA, NT5E, TMEM173, TMIGD2, TNFRSF25, and TNFRSF4 were significantly downregulated in MI samples, whereas C10orf54, ENTPD1, IL6R, TNFRSF9, and TNFSF13B were significantly upregulated (Figure 5E).