A new review and opinion article published in The Lancet by researchers from University College London (UCL) and University College London Hospitals (UCLH) has raised questions about whether blood transfusions could potentially transmit harmful brain proteins linked to Alzheimer's disease and other neurological conditions. The researchers are calling for further investigation and consideration of precautionary safety measures while scientific evidence continues to develop.
Professor John Collinge emphasised that blood transfusions remain an essential, life-saving medical treatment but said potential risks must be thoroughly examined to ensure the highest possible standards of patient safety.
The review focuses on amyloid-beta, a protein associated with Alzheimer's disease and cerebral amyloid angiopathy (CAA), a condition that can cause bleeding in the brain. The authors examined existing research to assess whether amyloid-beta pathology could potentially spread through donated blood.
One important study discussed in the review was a large Scandinavian epidemiological study published in 2023. It found that people who received blood from donors who later developed multiple brain haemorrhages, a possible indicator of CAA, had an increased risk of experiencing similar brain bleeds. Although the findings do not establish a direct cause-and-effect relationship, they raise questions about the possible transmission of amyloid-beta through blood transfusions.
Researchers also highlighted previous cases of medically acquired amyloid-beta diseases. These include iatrogenic cerebral amyloid angiopathy, which has been reported in patients who developed brain haemorrhages decades after receiving tissue transplants from deceased donors during childhood.
In 2024, Professor Collinge and colleagues reported five cases of acquired Alzheimer's disease in individuals who had received human growth hormone extracted from deceased donors during childhood. Earlier this year, the team documented another case in which Alzheimer's disease was confirmed through an autopsy. These cases demonstrate that amyloid-beta transmission has occurred in rare circumstances through historical medical treatments that are no longer used.
However, the researchers noted that the potential risks associated with modern medical procedures, particularly blood transfusions, remain uncertain. Developing reliable tests to detect amyloid-beta infectivity also presents significant technological challenges.
The review further examines lessons from the UK's Infected Blood Inquiry, published in 2024, which investigated the transmission of HIV and hepatitis C through contaminated blood and blood products. The inquiry highlighted the importance of taking timely precautionary action to protect patients.
The researchers also pointed to measures introduced in the UK to reduce the risk of variant Creutzfeldt-Jakob disease (vCJD), including filtering white blood cells from donated blood. These measures were adopted when the risk was still theoretical, demonstrating the potential value of preventive action in protecting public health.
Professor Collinge stressed that patient safety should not depend on waiting for absolute scientific certainty. He called for transparency, further research and careful assessment of potential amyloid-beta transmission risks to help ensure blood transfusions remain as safe as possible.
The review does not establish that Alzheimer's disease can be transmitted through routine blood transfusions. Instead, it highlights an area requiring further scientific investigation and discussion of appropriate precautionary measures.
References:
https://www.news-medical.net/news/20260821/Lancet-review-examines-possible-amyloid-beta-transmission-through-blood-transfusions.aspx
