Pathological proteins linked to Alzheimer's disease and cerebral amyloid angiopathy could theoretically be transmitted to patients through donor blood transfusions, according to a scientific review published in the medical journal The Lancet.
Researchers analyzing international clinical data highlighted evidence suggesting that transfusions of red blood cells may serve as a potential pathway for transferring amyloid beta, a protein whose accumulation damages brain tissue and cerebral blood vessels.
The concern stems from a major study conducted in Denmark and Sweden that monitored the medical records of more than 1.2 million blood donors and over 1 million blood recipients across both countries.
In that investigation, patients who received red blood cells from donors who subsequently suffered repeated brain hemorrhages were found to face a significantly higher risk of experiencing similar brain bleeding themselves.
Authors of the review explained that recurrent brain hemorrhages of this nature are a defining characteristic of cerebral amyloid angiopathy, a vascular brain condition closely associated with amyloid beta deposits.
Potential mechanisms of protein transfer
Scientists involved in the review noted that one potential explanation for the observed pattern is the transfer of microscopic amyloid beta particles during blood transfusions. These particles could act as seeds that trigger the accumulation of toxic proteins within the recipient's body.
However, the researchers stressed that there is currently no direct evidence proving that Alzheimer's disease is actually transmitted through donor blood. They emphasized that their analysis identified only a potential threat, and the exact magnitude of any associated risk remains unknown.
Rare cases of pathological protein transmission were previously identified following medical procedures that used preparations derived from human tissues. The new review expands on those findings by evaluating whether donor blood transfusions present another possible transmission route.
Understanding brain disorders and transfusion safety
Alzheimer's disease is a progressive neurodegenerative disorder that impairs memory and cognitive function, whereas cerebral amyloid angiopathy specifically weakens the walls of blood vessels in the brain, increasing the risk of strokes and internal bleeding.
Both conditions are driven by the accumulation of amyloid beta protein fragments. In modern healthcare, red blood cells, or erythrocytes, are routinely separated from donated blood and transfused to treat severe anemia, surgical blood loss, and traumatic injuries.
The Lancet, published in the United Kingdom, is one of the world's oldest and most respected peer-reviewed general medical journals.
Protective research and future outlook
While scientists continue to investigate how toxic proteins form and spread in human brain tissue, earlier research demonstrated that active substances found in ginseng can help protect the brain against the accumulation of toxic proteins.
