Aged immune systems hobble the ability of old people to fight off tuberculosis (TB). These aged immune systems also explain higher rates of death of old people from the flu and other infectious diseases.

COLUMBUS, Ohio – Manipulating the immune system in elderly people appears to be the most likely way to help older patients wage an effective battle against tuberculosis, a new study suggests.

Mathematical modeling of how mice respond to TB infection suggests that potential therapy options for elderly TB patients could either increase their white blood cell count or enhance infected cells’ interaction with their immune system.

This report illustrates how scientists trying to treat specific diseases end up running into the need to rejuvenate parts of the body. In this case what is needed is immune system rejuvenation.

Simulations of TB infection in an old mouse showed that increasing the number of infection-fighting white blood cells, called CD4 T cells, could be particularly effective at bolstering the mouse’s immune response, which naturally slows with aging. Older humans have similar delays in their immune response, meaning that they have a much more difficult time controlling TB than do younger people with an active infection.

The math modeling also suggested that making changes to macrophages, cells that essentially eat infecting bacteria, could enhance those cells’ interactions with other warriors in the immune system, reducing the concentration of bacteria in the lungs associated with TB infection.

As we age senescent immune cells end up displacing active immune cells and we need techniques for killing off the senescent cells. Imagine a machine that is analogous to a kidney dialysis machine that is specialized at separating senescent T cells from blood. If these old cells could simply be removed from the body the remaining T cells that retain the ability to divide could fill in the space made available by the removal of the senescent immune cells. Or perhaps a gene therapy could instruct senescent cells to commit cell suicide (apoptosis).

A rejuvenated immune system might itself kill off other senescent cell types. So methods to rejuvenate the immune system will provide many rejuvenation benefits. Plus, r, a younger immune system would probably reduce the incidence of cancer.