European scientists have identified two novel enzymes that could help convert blood groups A, B and AB into the universal O group.
The shortage of blood available for transfusion to those in need essentially arises precisely because of the shortage in the O group that could be donated to any one.
Now an international team led by Henrik Clausen of the University of Copenhagen in Denmark say that they have identified two novel glycosidase enzymes in bacteria.
The researchers hope that the enzymes will both improve the erratic supplies of blood around the world and also the safety of transfusions.
Clinical trials to test the safety and effectiveness of their converted blood are being planned, it has been reported.
The ABO blood-type system is based on the presence or absence of the sugar-based antigens 'A' and 'B' on red blood cells.
Type O blood cells have neither A nor B antigens, so may be safely transfused into anyone. But types A, B and AB blood do, and cause life-threatening immune reactions if they are given to patients with a different blood group.
The bacterial glycosidase enzymes strip these antigens away from A, B and AB blood, leading science journal Nature has said.
The idea of such antigen-stripping, says Nature, goes back to the early 1980s, with the discovery of an enzyme in coffee beans that removes B antigens from red blood cells.
The newly discovered bacterial 'B' enzyme is nearly 1,000 times more efficient than the coffee-bean B enzyme. The additional discovery of an enzyme to remove A antigens means that all blood types can now be converted.
Type O is the most common blood group, but stocks constantly run low because it is used in all emergency situations where there is no time to determine the patient's own group.
An additional pressure on type-O blood, particularly in the United States, comes from the mismatch between blood donors and recipients. Most US donors are Caucasian, amongst whom 45 per cent of people are blood group O. But more than half of African Americans, and nearly all native Americans are O, and so require type-O blood.