Can Alzheimer’s Proteins Spread Through Blood Transfusions? What to Know
Blood transfusions could potentially transmit harmful brain proteins such as amyloid-beta, according to a prominent medical review published in The Lancet. Led by John Collinge, MD, of University College London, and international colleagues, the expert panel convened to examine whether neurodegenerative disease pathology might be transmissible via blood and blood products, prompting calls for heightened vigilance and new screening assays across global healthcare systems.
The Lancet Review Raises Alarm Over Potential Brain Protein Transmission
- A medical review published in The Lancet warns that amyloid-beta pathology may theoretically be transmissible via blood transfusions, though actual clinical risks remain undefined.
- Researchers point to historical iatrogenic transmissions involving cadaveric growth hormone and an epidemiological study of over 1 million patients in Scandinavia as foundational drivers for this re-evaluation.
- Public health officials and blood services face mounting pressure to develop accurate screening assays to detect misfolded proteins and enhance transfusion safety.
The 2023 Scandinavian Study and Intracerebral Hemorrhage Risk
The risks of transfusion-related transmission of amyloid-beta pathology are currently undefined, and achieving clarity will take time, according to the review authored by Collinge and his team. The publication stems from an international workshop convened to review the accumulating evidence that amyloid-beta—a hallmark protein associated with Alzheimer’s disease and cerebral amyloid angiopathy (CAA)—might be transmissible through medical interventions involving human tissue or fluids.
This scientific re-examination was triggered in part by a large Scandinavian epidemiological study published in 2023. Led by researchers at the Karolinska Institute in Stockholm, that retrospective study of over 1 million patients across Sweden and Denmark indicated that recipients of red blood cells from donors who later experienced multiple intracerebral hemorrhages faced a significantly increased risk of developing spontaneous intracerebral hemorrhage themselves. While observational studies carry inherent limitations—such as the inability to perform detailed phenotyping to confirm CAA directly—the authors of the Lancet review suggest the findings align with a factor associated with intracerebral hemorrhage risk being transferable between donor and recipient. The most biologically plausible explanation, they note, is the transmission of amyloid-beta seeds.
Parallels to Prion Diseases and Historical Iatrogenic Transmission
Seeded protein misfolding and aggregation are central mechanisms in several neurodegenerative conditions. The clinical archetype for this phenomenon remains prions, which are protein-only infectious agents responsible for fatal neurodegenerative diseases like Creutzfeldt-Jakob disease. The research team first reported human-to-human transmission of amyloid-beta pathology in 2015 among patients who died of iatrogenic Creutzfeldt-Jakob disease after receiving treatment with cadaver-derived human pituitary growth hormone. Subsequent findings identified early-onset cerebral amyloid angiopathy in patients who underwent childhood medical procedures utilizing cadaveric dura mater. More recently, a 2024 case series suggested that children treated with contaminated growth hormone developed neuropathological changes consistent with Alzheimer’s disease.
Navigating Hematological Standards and Clinical Guidance
For patients and physicians managing complex hematological needs, staying informed about evolving blood safety standards is essential.
The Urgent Need for New Screening Tools and Global Research
Experts emphasize that acknowledging these knowledge gaps is a necessary step for modern transfusion medicine. Susan Kohlhaas, PhD, of Alzheimer’s Research U.K. in Cambridge, England, who was not involved in the Viewpoint article, noted that the review successfully identifies a critical research gap. The authors themselves stress that public health officials and blood transfusion services require further data on risk alongside feasible, accurate screening tools. Further research remains of strategic national and global importance to inform future policy discussions without inducing unwarranted public alarm.