There are strict rules to blood transfusion. Only blood without A- or B-type antigens, such as type O, can be given to all of those in need. But it's usually in short supply and thousands of patients need it every day.
Those rules may soon change.
As reported in the ACS Journal of the American Chemical Society, a group of scientists have found an efficient way to transform A and B blood into a neutral type that can be given to any patient.
As it stands now, blood transfusions require that the blood type of the donor match that of the recipient. If they don't, there are serious consequences-unless the donor has the 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.
Basically that is because the difference in 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.
It makes sense that by removing these sugars, there may be a to convert blood types A and B into type O. And a search for a method to do just that has been going on for some time.
Bacterial enzyme have been identified that can clip the sugars off red blood cells that give blood its "type." But the process isn't efficient enough to give any confident results.
Stephen G Withers and his colleagues wanted to see if they could boost the enzymes' activity. So they did.
By modifying one of those enzymes, they 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.
This discovery could have an impact beyond blood infusion by potentially allowing 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.
David H. Kwan, Iren Constantinescu, Rafi Chapanian, Melanie A. Higgins, Miriam P Kötzler, Eric Samain, Alisdair B. Boraston, Jayachandran N. Kizhakkedathu, Stephen G. Withers. Toward Efficient Enzymes for the Generation of Universal Blood through Structure-Guided Directed Evolution. Journal of the American Chemical Society, 2015; 150424072906003 DOI: 10.1021/ja5116088