Among the many changes that occur in the immune system with aging, the accumulation of CD28-CD8+ T-cells, referred to as senescent CD8+ T-cells, is strongly correlated with age, reduced vaccine efficacy, increased autoimmunity and the development of aging-related comorbidities such as frailty, bone loss and cardiovascular disease [46–47,54]. The gene discussed is CD8A; the disease is cardiovascular disorder.