For instance, the age-related immunosenescence affects infections since it (i) induces defects in the functions of neutrophils, (ii) decreases the responses of T cells, e.g., the affinity of TCR for antigens and the cytotoxicity of CD8 T cells, (iii) diminishes the maturation and antigen presentation by DCs, (iv) disturbs the functions of B cells, (v) down-regulates the activating receptors of NK cells [161, 163–165]. Here, CD8A is linked to infection.