Are umbilical cord derived stem cells from donors safe?

[Blue7]

I'm just wondering about this. They say it's hard to get graft vs host disease or any other bad reaction. I recently met a guy who said that they had a bad reaction from donated umbilical cord stem cell therapy. It's all so confusing, I don't know who to believe. Does anybody have knowledge on this subject?

 

[barbara]

Graft vs Host can be a problem, but was his bad reaction really that? It would be important to know what clinic he went to as well and where they obtain their cells.