By David Prentice

Editor’s note. This appeared yesterday on Dr. Prentice’s blog at http://www.frcblog.com/2011/01/in-the-womb-transplants-with-adult-stem-cells/

David Prentice

Transplanting adult stem cells into babies while still in the womb could potentially treat numerous genetic problems. But despite the fact that the immature immune system of an unborn baby can tolerate donor transplants, with little risk of graft rejection, most previous attempts to transplant blood stem cells into a human fetus have been unsuccessful. Now researchers at the University of California-San Francisco have an answer–match the transplant to the mother.

Using a mouse model, they showed that the mother’s T lymphocytes are the key involved in the previous puzzling rejection of such transplants. Some of mom’s T-cells infiltrate into the developing child, and react with transplanted donor cells. When transplants were matched to the mother rather than the fetus, the transplants were accepted.

Discovering this key to matching adult stem cell transplants for unborn babies could open the way for promising in utero treatments for a number of conditions. The researchers note that transplanting stem cells harvested from the mother or by HLA-matching the transplanted cells to the mother would be the preferred method. According to senior author Dr. Tippi MacKenzie:

"This research is really exciting because it offers us a straightforward, elegant solution that makes fetal stem cell transplantation a reachable goal. We now, for the first time, have a viable strategy for treating congenital stem cell disorders before birth."

Dr. MacKenzie says they can now "really think big" in terms of in-the-womb treatments for "everything from neurological disorders to muscular disorders before birth."

Lead author Dr. Amar Nijagal says:

"Transplanting stem cells harvested from the mother makes sense because the mother and her developing fetus are prewired to tolerate each other."

The study is published in the Journal of Clinical Investigation [http://www.jci.org/articles/view/44907]