A patient in the United States with the disease leukemia has become the first woman to be cured of HIV, the virus that causes AIDS. The patient received stem cells from a donor. Stem cells are special cells that can become any kind of cell in the body. The donor was naturally resistant to HIV, researchers told reporters Tuesday. The woman has been described as a 64-year-old woman of mixed race. Her case was presented at the Conference on Retroviruses and Opportunistic Infections in Denver, Colorado. It is the first case involving the use of blood from the umbilical cord. The umbilical cord connects a pregnant mother to her fetus. Use of umbilical blood is a somewhat new method. Doctors are considering making the treatment available to more people. The woman had been receiving the umbilical cord blood to treat her leukemia. Leukemia is a cancer that starts in blood-forming cells in bones. Since receiving the treatment, the woman has been in remission. She has been free of HIV for 14 months. She has not needed HIV treatments known as antiretroviral therapy.