Brain Proteins May Spread Via Blood Transfusions, Review Suggests

Harmful brain proteins, including amyloid-beta, may be transmissible through blood transfusions, according to a review published in the journal *Transfusion Medicine Reviews*. This potential transmission route raises concerns about the safety of blood products and suggests that additional research and enhanced safety measures are warranted to mitigate associated risks. The review highlights that while the direct evidence for human transmission of these proteins via transfusion is currently limited, the biological plausibility exists, necessitating a cautious approach.

Amyloid-beta is a protein fragment that normally exists in the brain and is a key component of amyloid plaques, which are characteristic pathological hallmarks of Alzheimer's disease. The accumulation of these plaques is believed to play a significant role in the neurodegenerative processes that lead to cognitive decline and memory loss associated with Alzheimer's. The review posits that if these proteins can enter the bloodstream and remain biologically active, they could potentially seed the formation of new plaques in the brains of transfusion recipients. This concept is analogous to the transmission of infectious agents, such as prions, which are known to cause neurodegenerative diseases like Creutzfeldt-Jakob disease (CJD) and can be transmitted through medical procedures, including blood transfusions and surgical instrument contamination.

The authors of the review emphasize that the current understanding of the risk is based on a combination of experimental data and theoretical considerations. For instance, studies have shown that amyloid-beta can be detected in blood, and animal models have provided some evidence for the spread of amyloid pathology following exposure to infected tissues. However, direct epidemiological evidence linking blood transfusions to an increased risk of Alzheimer's disease or other amyloid-related neurodegenerative conditions in humans remains scarce. The review calls for more rigorous studies to quantify this risk, including investigations into the stability and infectivity of amyloid-beta in stored blood products and the development of sensitive assays to detect these proteins in blood donations. Furthermore, the authors suggest exploring potential mitigation strategies, such as specific screening methods for blood donors or methods to inactivate or remove these proteins from blood products, although such interventions would require substantial validation and regulatory approval.

The implications of this potential transmission pathway extend beyond Alzheimer's disease, as other neurodegenerative disorders are also associated with the accumulation of misfolded proteins, such as tau in Alzheimer's and Parkinson's diseases, and alpha-synuclein in Parkinson's disease. While the review primarily focuses on amyloid-beta, the broader concern is that other proteinopathies could theoretically also be transmitted through blood. The medical community is urged to remain vigilant and to support further scientific inquiry into this complex issue to ensure the continued safety and efficacy of blood transfusion therapies.