Scientists have developed a simple method of converting blood from one group to another, which could potentially mean the end of blood shortages and boost supplies of sought-after group O negative blood.
O negative blood is known as "universal" because it can be given to anyone in a blood transfusion.
In research published in the latest issue of the journal Nature Biotechnology, an international team of researchers said they successfully converted blood from groups A, B or AB to group O.
People in groups A and B have blood containing one of two different sugar molecules which can trigger an immune response. Those in group O have neither of these "antigens", while those in group AB have both.
The scientists, led by Professor Henrik Clausen of the University of Copenhagen in Denmark, used bacterial enzymes as biological "scissors" to cut sugar molecules from the surface of red blood cells.
They started by screening 2,500 types of fungi and bacteria looking for useful proteins. Two bacteria, Elizabethkingia meningosepticum, and Bacteroides fragilis, yielded enzymes capable of removing both A and B antigens from red blood cells.
Researchers then verified the enzymes in standard laboratory tests. After an hour's exposure to the appropriate enzyme, the antigens vanished from 200 millilitre samples of A, B and AB blood.
"Clinical translation of this approach may allow improvement of the blood supply and enhancement of patient safety in transfusion medicine." said researchers.
Clinical trials will be conducted before group O blood produced by the conversion method can be used in hospitals.