A rare side effect of human fetal stem cell therapy described in the journal PLoS Medicine raises questions about the success of this kind of therapy.

 

In 2001, an Israeli boy, underwent human fetal stem cell therapy at a Moscow hospital. He was suffering from Ataxia Telangiectasia, a childhood neurological disorder that causes degeneration in the part of the brain that controls motor movements and speech. Lacking a strong immune system, patients suffering from it are prone to frequent infections and cancers. Most of them die in their teens or early 20s.

 

The boy, 9, whose identity was not revealed, was injected with neural stem cells from fetuses-immature cells destined to grow into a main type of brain cells. The procedure was repeated twice more, at ages 10 and 12.

 

By the time he was 13, the disorder put him in a wheelchair and he also began complaining of severe headaches. His doctors, Ninette Amariglio and Gideon Rechavi from the Sheba Medical Centre in Tel Aviv found two tumors - one in the spine and one in the brain at the same sites the injections had been given.

 

One year later, the doctors removed the tumors, which were benign, and had them tested. The tests found that the tumors contained cells that could not have arisen from the patient’s own tissue and had in all probability grown from the donated stem cells.

 

“This is worrying and we have to be cautious. We need to have long term monitoring an follow up of the patients given stem cells and rigorous regulation of centres providing cell therapy,” Stem cell scientist Dr Stephen Minger, of King's College London told BBC News.

 

The authors of the paper in the PLoS concluded that “extensive research into the biology of stem cells and in-depth preclinical studies, especially of safety, should be pursued in order to maximize the potential benefits of regenerative medicine while minimizing the risks.”