In utero transplantation of stem cells in humans.

Three human fetuses were treated by stem cell transplantation from fetal liver. Two of them had severe immunodeficiency disease and the third one had thalassemia major. All three in utero transplants were followed by engraftment. No adverse effect was seen. The three patients are now born: the first one is cured, the two other ones are still under investigation. This procedure, for the first time used in humans, is therefore shown to be an effective and safe therapy of inherited diseases, during early fetal development.