A recent case in JASN talks about a new complication seen with stem cell infusion. Please have a look at this news from the BBC website. Stem cells were injected into the kidney, but the patient suffered tissue damage and died from an infection. Perhaps the enthusiasm is still too early. Although the animal studies have shown promise of stem cell therapy in renal disease, in this particular cae, they found that the patient had not benefited at all from the treatment, but had actually developed tissue damage called angiomyeloproliferative lesions at the injection sites. These were found to be clusters of blood vessels and bone marrow cells. What is angiomyeloproliferative lesion: could be a precede cancer. The neoplastic potential, of this lesion is unknown.
More work is needed in this field to clarify these effects.