Researchers at the Sutter Neuroscience Institute in Sacramento, California, will conduct the first trial of its kind to be approved by the US regulator, the Food and Drug Administration.
Despite very few trials anywhere else in the world, stem cells treatments are openly marketed as therapies for autism in many countries. Dr Michael Chez, director of pediatric neurology at Sutter Medical Centre, who will be the study's principal investigator, told Nature Medicine's blog that the trial is 'important because many people are going to foreign countries and spending a lot of money on therapy that may not be valid'.
However, said Dr Chez, there is 'evidence to suggest that certain children with autism have dysfunctional immune systems that may be damaging or delaying the development of the nervous system'.
'Cord blood stem cells may offer ways to modulate or repair the immune systems of these patients', Dr Chez continued. Stem cells may also 'improve language and some behaviour in children who have no obvious reason to have become autistic'.
The trial will involve thirty children between the ages of two and seven where any identifiable cause for autism, such as a genetic condition or brain injury, remains elusive. Half of the trial group will be injected with the stem cells, the other half will receive placebo injections.
Both groups will be monitored for a period of six months, before switching to the opposite arm. The trial will be 'blind'; for the duration neither participants nor clinicians will know which arm of the trial they are on, to prevent biased results.
'Parents want so desperately to see a response, and therapists want to see a response, if you don’t have an appropriately blinded control study, you get an elevation of observation of response', Dr Chez told Bloomberg. 'That's true for any disease that has no cure, but more so with something subjective like autism'.
Clinicians will monitor patients' language and behaviour to assess whether any therapeutic benefit has occurred. Even if the trial is unsuccessful researchers expect it to provide valuable insight into the nature of autism spectrum disorders.
Some researchers are less than optimistic about the trial's outcome, however. Dr James Carroll, a paediatric neurologist at the Georgia Health Sciences University in the USA, has been running a clinical trial using stem cell therapy in patients with cerebral palsy for two years. 'So far we have not seen any kind of miraculous recovery in our cerebral palsy patients', he told the Nature Medicine blog, 'I would be delighted if that changes'.
Dr Ricardo Dolmetsch, a neurobiologist and autism researcher at Stanford University told Bloomberg: 'I commend them for having the guts to actually do [the trial], given that there are all kinds of people out there trying to sell [stem cell therapies]'. However he added that he did not think the trial would be 'big enough to provide an answer'.
According to the Centres for Disease Control and Prevention in the USA, one in 88 children in America is affected by an autism spectrum disorder. The results of a recent trial in China using donated cord blood stem cells are yet to be published, and researchers in Mexico are still in the early stages of a trial using stem cells harvested from participants' own fat tissue.