‘Alzheimer’s link to blood transfusions’
Expert calls for donations from the over-60s to be screened
‘Disease is not transmissable’
BLOOD donated by the over-60s should be screened amid fears it could spread Alzheimer’s disease, a leading scientist has warned.
New research suggests that one of the potential causes of Alzheimer’s, a sticky plaque that grows in the brain, could be transmitted.
Now experts warn there is a risk it could be carried in donated blood or carried on surgical instruments.
In a series of tests, scientists injected mice with the toxic plaque and found they went on to grow further plaques in their brains.
They stress they have not found that Alzheimer’s disease itself can be passed on.
The research shows the build-up of toxic plaque on the brain seen in Alzheimer’s patients can be triggered by tiny protein ‘seeds’.
Professor John Hardy, of University College London, who was not involved in the research but is an international expert, said: ‘Neurosurgical procedures which involve persons with dementia should be carefully monitored for transmissito bility issues as should blood transfusions from the elderly (60+) and from persons with a family history of early onset dementia.
‘It is possible that neurosurgical instruments could be contaminated with amyloid seeds – though there is no evidence of this from this study – and it is of course appropriate to continue to be vigilant in order to avoid cross-contamination.
‘However there is absolutely no reason to postpone or decline brain surgery based on the current evidence.’
CJD – the human form of mad cow disease – is spread by tiny substances called prions. The latest research shows that an important part of Alzheimer’s disease may be spread in a similar way. Researchers made a previous breakthrough from studying the brains of eight patients who had died of CJD.
They had all received a contaminated human growth hormone in the 1980s. Six of the eight had the memory-robbing plaque in their brains.
Lead author of the latest research, Professor John Collinge, also of UCL, suspected that the amyloid plaques were not being caused by CJD. He traced the 30-year-old batch of growth hormone and found that, as well as containing prions, it also harboured the Alzheimer’s-linked protein seeds.
He said: ‘It is most important emphasise that there is no suggestion in our work that you can catch Alzheimer’s disease (or indeed CJD) by contact with a person with the disease.’
Modern human growth hormone has no risk of passing on infections as it is now made synthetically. Professor Bart de Strooper, director of the UK Dementia Institute said a 2016 study tracked 1.5million people involved in blood transfusions and found no evidence of an increased chance of Alzheimer’s for those who received blood from people who were later found to have Alzheimer’s.
An NHS Blood and Transplant spokesman said: ‘The research paper authors say there is no suggestion Alzheimer’s disease is transmissible by blood transfusion. There is no evidence for a change to the age guidelines on blood donation. Any evidence for a change would be a matter for policy-making bodies.’