Premature use of stem cell therapy could put patients at risk

The premature use of stem cell therapy could put many patients at risk of viral or prion diseases unless appropriate safety systems are in place, warn experts in this week’s BMJ.

The use of human embryonic stem cells has been hailed as the next major step in the battle against serious degenerative disorders, such as diabetes and Parkinson’s disease. But is this just hype, and how much hope should patients invest in this technology? These are some of the issues that will be discussed at a public debate in London next week.

The lessons of premature application of gene therapy, the devastation caused by HIV transmission to people with haemophilia, and the crisis caused by bovine spongiform encephalopathy (BSE) should all be learning opportunities, say the authors.

Expansion of stem cell cultures could allow a single stem cell line to be used for many hundreds, if not thousands of patients, exponentially amplifying the potential risk of disease transmission from a single infected donor.

Change is on the way, however. By April 2006, all laboratories for in vitro fertilisation and laboratories for producing cell lines with therapeutic intent will have to comply with the EU Directive on tissues and cells. This will cover selection of donors, testing, and procurement of the starting material for cell lines, tracking cells from donor to recipient, and reporting of adverse events.

The authors suggest a novel alternative approach whereby the expanded stem cell lines themselves could be tested for a variety of pathogens before they are released. This would provide an additional safety step and provide an alternative in the armamentarium for testing these important donations for transplantation.

The drive to be the first to produce cell lines for therapy without appropriate controls could compromise safety for recipients and could lead this technology into the realms of quackery, say the authors. Such fears are already being realised in India and Russia, where action may be needed to limit or prevent the escalating numbers of clinics offering stem cell cures for all sorts of ills.

Stem cell therapy needs to be nurtured safely and methodically to provide real benefit to patients in the future, they conclude.

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