Researchers have developed a tissue typing technique to determine the compatibility between organ donors and organ recipients. Each individual has a unique set of cell and tissue “markers” called HLA antigens. George Snell (1903–1996), Jean Dausset (1916-) and Baruj Benacerraf (1920-) shared the Nobel Prize in Physiology or Medicine in 1980 for their research on identifying and understanding the genetic structure of cell and tissue markers. The more similar the cell and tissue markers are between donor and recipient, the less likely there will be tissue rejection or graft-versus-host disease.