How do you cure a man of both leukemia and AIDS with just one procedure? No, it’s not a trick question: an American leukemia patient living in Berlin received a bone marrow transplant that also resolved his AIDS.

In a bone marrow transplant, a patient’s own marrow is destroyed and replaced with tissue from a donor. The donor marrow contains healthy hematopoietic stem cells (HSCs, adult stem cells in the blood) which repopulate the patient’s body with healthy red and white blood cells for oxygen transport and immune defense. Just as with other varieties of organ donation, tissue-type matches are critical. In the case of More >