In 2009, scientists from University of California Los Angeles were able to grow T lymphocytes (or cells that fight infection) from human stem cells that were genetically altered. This year, they were able to further engineer the cells to seek out for cells that were infected by HIV and kill them. These engineered T cells are then introduced into the body, where they seek out and kill the infected cells. For example, patients undergoing ART could also receive infusions of these engineered T cells to help clear the remaining infected cells that ART alone cannot eliminate. The same principles used to engineer T cells to fight HIV could be applied to other viruses, such as hepatitis C or even certain types of cancer.