Immune System Aging in a Nutshell
A review paper: "With the improvement of medical care and hygienic conditions, there has been a tremendous increment in human lifespan. However, many of the elderly (older than 65 years) display chronic illnesses, and a majority requires frequent and longer hospitalization. The robustness of the immune system to eliminate or control infections is often eroded with advancing age. Nevertheless, some elderly individuals do cope better than others. The origin of these inter-individual differences may come from genetic, lifestyle conditions (nutrition, socio-economic parameters), as well as the type, number and recurrence of pathogens encountered during life. The theory we are supporting is that chronic infections, through life, will induce profound changes in the immune system probably due to unbalanced inflammatory profiles. Persistent viruses such as cytomegalovirus are not eliminated and are a driven force to immune exhaustion. Because of their age, elderly individuals may have seen more of these chronic stimulators and have experienced more reactivation episodes ultimately leading to shrinkage of their repertoire and overall immune robustness." Evidence in recent years suggests that this issue can be addressed by selectively destroying immune cells devoted to largely useless causes such cytomegalovirus - a goal that becomes ever more practical as targeted cell-killing therapies move closer to the clinic.