CD8A and congestive heart failure: Furthermore, we found the positive relationship between congestive heart failure and preoperative relative abundances of both CD69+CD8+ T cells and HLA-DR+/CD40+ classical monocytes, with the former suggesting T cell activation and the latter involved in antigen presentation and cytokine secretion [44,45,52,53], and these results are consistent with previous studies [54,55,56].