No sign Alzheimer's, Parkinson's spread through blood transfusion

By Anne Harding

NEW YORK (Reuters Health) - Neurodegenerative diseases such as dementia and Parkinson's do not seem to be transmissible by blood transfusion, new findings show.

"We have absolutely no signal that something is being transmitted," Dr. Gustaf Edgren of Karolinska Institutet in Stockholm, the study's first author, told Reuters Health in a telephone interview.

Prion diseases such as variant Creutzfeldt-Jakob disease (vCJD) can be spread through blood transfusion, Dr. Edgren and his team note in their report, online June 27 in the Annals of Internal Medicine. Questions have been raised about whether neurodegenerative disorders characterized by aggregation of abnormally folded proteins - similar to what occurs in prion disease - might also be transmissible through transfusion.

To investigate, the researchers looked at the Scandinavian Donations and Transfusions (SCANDAT2) database, which has included complete data on blood donation and transfusion from blood banks in Sweden and Denmark since 1995 and 2003, respectively.

Their analysis included more than 1,460,000 patients who received transfusions between 1968 and 2012. The researchers also looked at transmission of hepatitis C before and after the implementation of screening for the virus.

A total of 2.9% of recipients received a transfusion from a person with dementia, Alzheimer's or Parkinson's disease. The researchers found no increase in these individuals' risks for dementia (hazard ratio, 1.04; 95% CI, 0.99-1.09), Alzheimer's disease (HR, 0.99; 95% CI, 0.85-1.15) or Parkinson's disease (HR, 0.94; 95% CI, 0.78-1.14).

However, they did find transmission of hepatitis C before but not after 1992, when donor hepatitis C virus screening had been fully implemented in both countries.

"I think this is about as confident as I can be of this type of observational data that there's not transmission (of dementia, Alzheimer's or Parkinson's) going on," Dr. Edgren said.

He and his colleagues conclude that the findings "offer reassurance for the fields of transfusion medicine and general medicine and for transfusion recipients in showing that such transmission must at least be rare or result in average induction times exceeding 20 years."

SOURCE: http://bit.ly/29eLdNg

Ann Intern Med 2016.

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