Children with autism spectrum disorder (ASD) who received infusions of their own stem cells from banked umbilical cord blood as part of a clinical trial have no apparent lasting adverse effects after one year.
Parents of some of the 25 children in the study – who were aged between two to five – reported that their kids showed reduced signs of ASD after the treatment. However, improvements in behaviour were correlated with the child's IQ (which was measured before the study) and not with the quantity of stem cells the children received. This may mean that improvements seen were due to the children learning new skills and coping methods and not to the therapy.
Reduction in ASD-related behaviour was measured by questioning the parents and by clinician-administered tests. Around 40 percent of the children in the trial exhibited no improvement.
A similar study reported on in 2016, led by Dr Michael Chez, director of Paediatric Neurology at the Sutter Institute, California and involving 30 children, showed a similar percentage of reported improvement (see BioNews 670).
The team involved in the latest trial, led by Dr Geraldine Dawson and Dr Joanne Kurtzberg from Duke University Medical Center, North Carolina, are now running a second, larger trial on whether cord blood can treat autism. The double-blind, placebo-controlled trial involving 165 autistic children aged two to eight will be overseen by the US Food and Drug Administration.
Some observers have questioned the science underlying the study. 'It's probably premature to run large trials without evidence that they have a therapeutic effect that [we] understand,' said Dr Arnold Kriegstein, director of the Broad Center of Regenerative Medicine and Stem Cell Research at the University of California, San Francisco, who was not involved in the research. 'I think it would be marvellous if this trial worked, but it really seems more like a "Hail Mary pass" than a rational therapy,' he said in 2014.
Cord blood stem cells can be collected from the umbilical cord and placenta and then stored in cord blood banks for future use in cellular therapies or blood stem cell transplantation.
Previous research has shown that cord blood stem cells can help reduce inflammation and signal cells to help repair damaged brain areas. While there is a hypothesis that some signs of autism are due to inflammatory processes in the brain, autism spectrum disorders are complex and may have many possible causes, including differences in the development of neuronal connections or mitochondrial function. Blood stem cells cannot replace neurons, although they may be able to enter the brain after infusion into the blood.