Genetics and stem cells

Warning over stem cell therapy

The experimental use of stem cells for kidney repair has been linked to complications in a patient with kidney disease, the BBC has reported. It said that stem cell injections were followed by tissue damage in the patient, who later died from an infection.

The story is based on a case report on a 46-year-old woman with end-stage kidney disease who underwent stem cell therapy in a private clinic in Thailand. The woman’s condition did not improve after stem cells were injected into the regions of both of her kidneys, and so three months later she began dialysis. She was later found to have abnormal growths of tissue in and around her kidneys that the authors of the case report suspect were caused by the therapy. The patient later underwent removal of her left kidney but gradually deteriorated and died.

This detailed case report, which highlights a previously-unseen complication of stem cell treatment, illustrates the need for further research into the potential side effects of this complex experimental therapy. As an accompanying editorial points out, the growth in the number of private clinics offering experimental stem cell therapies is worrying, given the lack of regulation or reliable information on their safety.

Where did the story come from?

The case was reported by researchers from Chulalongkorn University in Thailand, the University of Toronto and the Hospital for Sick Children in Toronto, Canada. It was published in the peer-reviewed Journal of the American Society of Nephrology.

The BBC reported the study accurately.

What kind of research was this?

This was a case report that describes in detail stem cell therapy and its outcome in an individual patient with kidney disease. Case reports can be useful in helping to detect rare but important adverse events associated with treatments; particularly new or experimental treatments. As a type of anecdotal evidence, they are less reliable than observational studies or controlled clinical trials. However, they may prove useful as a means for gaining preliminary information in areas where controlled trials are not appropriate or ethical.

Case reports are particularly valuable in a relatively new and fast developing field such as stem cell treatment, as they can inform us of adverse events that have not been identified yet.

While animal studies have indicated that stem cell treatments may improve outcomes in kidney disease, and some successful treatments have been reported in humans, the treatment remains unproven in terms of risks and benefits.

What did the research involve?

The researchers describe the case of a 46-year-old woman with lupus nephritis, a serious inflammation of the kidneys (nephritis) caused by a chronic autoimmune disease (systemic lupus erythematosus).

Despite drug treatment, her condition had progressed to end-stage kidney disease. The patient decided to undergo stem cell treatment, performed using her own stem cells at a private clinic. Stem cells were collected from the bloodstream and later directly injected through the skin into the regions of both kidneys. Additional details of the treatment were not available.

What were the basic results?

The woman’s condition did not improve and, three months after the stem cell therapy, she began dialysis. Six months after therapy, she had pain on the left side and blood in her urine. Investigating these symptoms with imaging scans showed she had developed abnormal tissue masses in her left kidney and nearby organs. Based on these scans the doctors suspected these were cancerous growths.

Eleven months after stem cell treatment, the left kidney was removed. The woman continued receiving haemodialysis over the next year but gradually deteriorated and died of blood poisoning (sepsis) after developing an infection.

An examination of the removed left kidney revealed various masses of abnormal, apparently non-cancerous tissue growths (lesions) in various parts of the left kidney, which the authors say were caused by the stem cell injections she had previously received. They also say that similar lesions found in the liver and right adrenal gland may have been the result of injections into the region around the right kidney (which did not appear to contain lesions). Her death was not followed by an autopsy so it is not known if the lesions had persisted or spread to other parts of the body.

How did the researchers interpret the results?

The researchers say this is the first time abnormal tissue been reported after stem cell therapy. They believe the lesions had something to do with the stem cells being injected directly into the region of the kidneys, rather than being introduced into the blood stream, as is more common in experimental stem cell therapies. Although the lesions appeared benign (non-cancerous), it is not known how they developed and whether they could have then developed into cancer.

The researchers say that results from animal experiments have found stem cell treatment to be safe for the kidneys, with clinical trials planned to expand this type of treatment in humans. They say the case presents a“note of caution’ for patients embarking on such a course of experimental stem cell therapy.


This is a detailed, well-reported description of a patient who developed a serious and unexpected complication following stem cell treatment for end-stage kidney disease. It seems likely, as the researchers point out, that the complication was directly associated with the treatment itself, which, it is important to note, had no benefit for the patient who died some two years later. However, on the basis of this single case alone, further research is needed to find out if and how stem cell treatment could directly cause these complications.
There have been impressive advances in stem cell biology, triggering optimism about the potential of future therapies. As with all new complex treatments, the potential risks need to be carefully evaluated through various stages of clinical research.

NHS Attribution