The University College London scientists have found that age-related reductions in skin immunity are not necessarily caused by defects in T cells. Instead they may be due to the skin’s inability to attract these cells to the sites of infection or damage.
The research prompts the question of whether other tissues in older people may have the same underlying age-related defects that increase their susceptibility to conditions such as lung cancer or pneumonia.
The studies are due to be published in the August 31 edition of The Journal of Experimental Medicine. The paper is titled “Decreased TNFalpha synthesis by macrophages restricts cutaneous immunosurveillance by memory CD4+ T cells during ageing.”
The University College London team studied both healthy young volunteers (under 40 years of age) and an older group of over-70s. They found nothing wrong with the T cells in the older group but did observe that their skin cells couldn’t mobilize immunological defense mechanisms. Moreover, in vitro studies demonstrated that it may be possible to make older skin express the missing signals required to attract T cells.
The ability to induce signal expressions suggests that the process is reversible, points out lead author, Arne Akbar, Ph.D. “Once we get to the bottom of exactly which part of the signal to T cells has gone wrong, we might then be in a position to intervene to boost skin immunity in older people.”