For one, CD4+ T cells accumulate in the heart post-MI and -TAC, and are associated with enhanced cardiac fibrosis (Laroumanie et al., 2014; Nevers et al., 2015, 2017; Bansal et al., 2017, 2019; Borg et al., 2017; Quast et al., 2017). The gene discussed is CD4; the disease is myocardial infarction.