Specifically, we will review the issue of blood donation from PD patients. We will present the evidence, sample the prevailing attitudes and policies, and then make our recommendations.
Part I of this series discussed the similarities between the possible cell to cell progression of Parkinson’s pathogenesis and contagious proteinaceous pathogens called prions. Despite these similarities, there is no evidence of person to person transmission of Parkinson’s disease. Parkinson’s disease is not contagious.
However, the next form of transmission we need to consider is transmission through blood and tissue. We have seen the evidence that human α-synuclein is the prion-like culprit of PD pathogenesis, capable of transmission. Here is a brief review:
• α-synuclein aggregates are toxic in living cells
• Pathological human α-synuclein can be inoculated or seeded into the brains of animals, initiating a PD-like disease in those animals
• Animals can even be “infected” by injecting the protein into their muscle tissue. This “infection” then appears to travel up the sciatic nerve on its way to the brain.
• Transplantation of fetal cells in PD subjects became “infected” 14 years after grafting.
Animals don’t get PD and it is difficult to make conclusions from these animal experiments about the possibility for inoculation of PD in humans. However, since α-synuclein seeding appears to occur in animals, it would be wise to be cautious about human PD inoculation.
The best evidence against PD transmission comes from two epidemiological studies.
1. A group of 6018 people with hemophilia in the UK were tracked for between 2 and 23 years. This disease is traditionally controlled with regular infusions of blood clotting factor extracted from human blood serum. The study did not find increases in mortality other than from HIV and from those causes that would be expected from this population of patients. There was also no evidence of deaths from Creutzfeldt-Jakob disease (CJD), a human prion disease.
2. Patients treated with human growth hormone (hGH) have traditionally used a product extracted from cadaveric pituitary glands. These patients were followed and their cause of death determined. The mean age of death was a young 27.2 years. This study did indeed find instances of CJD transmitted through this procedure. However, they did not find evidence of PD transmission.
These observations cast doubt on the possibility of PD transmission, however there are alternate explanations for these observations:
• Infectious α-synuclein material does not survive the extraction process.
• A long incubation time for PD obscures the analysis and tracking for reduced lifespan illnesses or short tracking times. Assuming a 20 year incubation time and a 15 year post diagnosis lifespan, tracking would likely miss this population.
A recent review of this issue recommended that “a thorough decontamination of surgical instruments and other medical devices from aggregated Aβ-, tau- and α-synuclein by effective and routinely applicable reprocessing procedures may possibly add to patient safety.”
Yet despite the conflicting evidence, PD patients are typically not discouraged from donating blood or organs.
• The American Red Cross, does not list Parkinson’s disease on their list of those not eligible to give blood.
• The New Zealand Blood Service does not allow PD patients to give blood only because it considers donating a health risk to PD patients.
• The Central California Blood Center explicitly allows PD patients to give blood.
• The Australian Red Cross explicitly encourages PD patients to donate blood. In fact, PD patient, Alan Harvey, is celebrated in marketing material for having made 400 blood donations as of Winter, 2013.
The only blood service in our limited sampling that forbids blood donation from PD patients in order to protect its blood supply is the United Kingdom’s NHS Blood and Transplant. The official statement on Parkinson’s patients is: “We are very sorry but sadly you are not able to donate blood. This is either for the safety of yourself in giving blood or for the safety of patients that receive your blood.” A BBC article suggests the reason is the “uncertain origin” of the disease.
PD professionals and pundits almost universally approve of blood donation from PD patients:
• Monique L. Giroux, MD. Medical Director of the Northwest Parkinson’s Foundation states very confidently “Parkinson’s disease is not a condition transmitted by blood so having PD does not exclude a person from giving blood.”
• Michael S. Okun, M.D. National Medical Director of NPF, UF Center for Movement Disorders & Neurorestoration feels PD patients can give blood as long as they don’t have low blood pressure.
• The Answers.com entry on the issue states: “Depending on medications and general health it would be fine.”
• Chacha.com answers that donating blood would be fine “Since Parkinson’s is not a transmittable disease“.
In our opinion, of all the blood donation services and PD professionals, the UK’s NHS has provided the only accurate statement on this serious issue. As of the date of this post, evidence suggesting at least the possibility of blood to blood transmission of PD is not insignificant. To proclaim otherwise is irresponsible at best. We propose, therefore, the following recommendations until definitive conclusions about blood-borne transmission of PD are possible.
1. That worldwide blood donation policy groups PD with prion diseases like CJD.
2. Until such policy is enacted we urge all PD patients to voluntarily refrain from giving blood and from consenting to donate organs.
3. We urge the tracking of blood donors who either had PD at the time of blood donation or who gave blood at any time prior to being diagnosed with PD.
4. Recipients who have received such blood should be informed and tracked by PD status, including testing for early pre-motor symptoms (a smell test, for example) and PD markers (when they are developed).
5. Recipients should initiate a neuroprotective prevention protocol based on all applicable research. Our team has a good idea what such a protocol would look like and we plan to publish a prevention protocol in the near future.
6. All references to blood donation also include organ donation.
It is our hope that concern about blood supplies will provide an additional incentive to better fund research on Parkinson’s disease and indeed all those diseases of uncertain origin.
Researcher at Stop Parkinson's
Dr. Steve is a biochemist, specializing in medical bioinformatics and nutrition. Dr. Steve directs a biomedical consulting laboratory, focusing primarily on biomedical investing and health policy.