London, Jan 31: According to a new study by researchers at Stanford University, California, a blast of sunshine could help fight skin diseases and cancer by attracting immune cells to the skin surface. Eugene Butcher at Stanford University in California, US, and colleagues discovered an interesting immune process in human skin. The researchers noted that sunshine regulates immune cells in the skin, called dendritic cells, which convert vitamin D3 (produced in exposed skin in response to sunlight) into its active form.

This "active" vitamin D3 then causes T-cells to migrate to the uppermost layer of the skin, Butcher`s team found. T-cells are the immune cells that destroy damaged and infected cells, and they also regulate other immune cells. The findings explain how T-cells "know" to go to the skin`s surface once the skin has suffered some sun-induced DNA-damage, the researchers say. "Sunshine is good for you, as long as it`s not too much," New Scientist quoted team member Hekla Sigmundsdottir, as saying.She points out that the skin disorder psoriasis is sometimes treated with vitamin D3 creams - it may work by moving T-cells into the skin, she speculates.

The finding adds to a growing body of evidence that dendritic cells, which live in tissues that are exposed to the outside environment, such as the skin and nose, run "traffic control" for the immune system, interpreting local conditions and directing T-cells to where they are needed.