When it comes to donated blood, type O is special. It can be given to anyone, regardless of their blood type. By contrast, type A can only go to A or AB patients, and B can only go to B or AB patients. Additionally, type O patients can only receive O. Thanks to new research, however, it may soon be possible to give anyone whatever type of blood happens to be available, with no ill effects.
The reason that type O is so transfusion-friendly is that it contains no A or B antigens – these will provoke a severe immune response in bodies where they aren't already present.
UPGRADE TO NEW ATLAS PLUS
More than 1,200 New Atlas Plus subscribers directly support our journalism, and get access to our premium ad-free site and email newsletter. Join them for just US$19 a year.UPGRADE
For some time now, scientists have been looking at using enzymes derived from bacteria to "clip" the A- or B-specific sugars (aka antigens) off of red blood cells, to create a sort of generic blood that can be given to anyone. Unfortunately, however, those enzymes haven't been very effective – a huge amount of them would be required in order to have an appreciable effect.
That could be about to change, though. A team from the University of British Columbia and the Centre for Blood Research has created a "mutant" enzyme that's much more effective.
They did so by inserting mutations into the bacterial gene that codes for the enzyme, then subsequently selecting mutants that were particularly effective at clipping off the antigens. After doing so for five generations, they ended up with an enzyme that was 170 times more effective at antigen-clipping than its original predecessors.
In lab tests, the enzyme has been shown to remove most of the antigens in type A and B blood. Before the technology can be applied to humans, however, it needs to be advanced to the point that it removes all of the sugars – even a few incompatible antigens in a transfusion can still be very harmful.
A paper on the research was recently published in the Journal of the American Chemical Society. As a side note, scientists at other institutions are developing both artificial blood and lab-grown blood.