2019-07-29 · Iris Gratz, member of the ACBN focus program of the University of Salzburg, and colleagues have discovered a population of human immune cells in the blood that appear to have everything in common with infection-fighting T cells isolated from the skin. The findings were published in the journal  Science Immunology and were featured on the July cover of the journal.

The work challenges current thinking that skin-resident memory T cells are strictly retained in the skin. Iris Gratz and her team, in partnership with Daniel Campbell at the Benaroya Research Institute at Virginia Mason (BRI), and scientists at the University of Pennsylvania and other research institutions, demonstrated that tissue-resident memory T cells can exit skin tissue, enter the blood and circulate throughout the body. These T cells can then relocate into skin at other locations of the body.

By studying these T cells in more detail, Gratz and colleagues found that the migration of the T cells likely plays a role in the healing of skin wounds and the ability to recognize and protect against infection. “Once these cells have battled an infectious agent at one site on the skin, they may be able to recognize and fend off infection at other sites and in subsequent encounters,” the researcher said. The discovery of tissue-resident memory in the circulation of healthy individuals greatly facilitates the isolation and study of cutaneous memory T cells from a broadly available human tissue, the blood.