Transforming all donated blood into a universal type

Stephen G. Withers and colleagues note that currently, blood transfusions require that the blood type of the donor match that of the recipient. If they aren't the same, a patient can suffer serious side effects, and could even die. The exception is the universal-donor blood type O, which can be given to anyone because it doesn't have the A or B antigens that could provoke an immune reaction. For years, scientists have been searching for a way to convert types A and B into type O. They found that some enzymes from bacteria can clip the sugars off red blood cells that give blood its "type." But the enzymes are not very efficient. Withers' team wanted to see if they could boost the enzymes' activity.

The researchers tweaked one of those enzymes and improved its ability to remove type-determining sugars by 170-fold, rendering it antigen-neutral and more likely to be accepted by patients regardless of their blood type. In addition to blood transfusions, the researchers say their advance could potentially allow organ and tissue transplants from donors that would otherwise be mismatched.

The authors acknowledge support from the Canadian Blood Services, the Canadian Institutes of Health Research, Health Canada and the Michael Smith Foundation for Health Research.

Background on Blood types

The defining difference between A, B and O blood types is the presence of slightly different sugar structures on the outside of the red blood cells of each type. Type A and B blood cells each have a single additional sugar attached to their surface.