In-utero transplantation of fetal liver stem cells into human fetuses.

Three human fetuses were treated by transplantation of human fetal liver stem cells. Two of them had severe immunodeficiency disease and the third had thalassaemia major. All three in-utero transplants were followed by engraftment. No adverse effect was seen. The three patients have now been born: the first is very healthy thanks to the reconstitution of cell-mediated immunity associated with this transplant, and he lives normally at home; the other two, who were treated more recently, have not yet shown a complete effect. The feasibility and efficacy of this procedure, used for the first time in humans, has therefore been demonstrated: during early fetal development, foreign cells engraft readily and may result in significant improvement of a large variety of inherited diseases.