Immune Function and Aging
Age is largely determined by the state of your immune system. As we age, our immune system becomes less effective and more inflammatory. Chronic inflammation accelerates all age-related illnesses. To name just one example, chronic inflammation disrupts tissue regeneration and maintenance. The degree of damage and dysfunction in the immune system is likely to be a large component in the variation in aging.
Immune aging can be attributed to the accumulation of pathogens in a person’s lifetime. In particular, persistent infections, like cytomegaloviruses and herpesviruses are thought to contribute to immune aging. A portion of immune aging is caused by the atrophying thymus organ, which is responsible for maturing T cells. Less thymic tissue is active, which means that fewer T cells are available to defend the body. Inflammatory activity can be triggered by gut bacteria when barriers fail in the gut. Immune aging can be caused by cellular senescence in immune cells that turns them into centers of inflammation signaling. These issues all have solutions but, like in other aging-related matters, they are not given enough funding or attention.
Source:
https://www.fightaging.org/archives/2019/03/immune-function-as-a-determinant-of-aging-and-longevity/