Can Scientists Turn Type A Blood Into Universal Type O?

Bacteria found in the human gut could help save lives by transforming Type A blood into Type O blood.

At a meeting of the American Chemical Society on Tuesday, Steve Withers of the University of British Colombia presented his new research. Newly discovered bacterial enzymes that were kodged in the human gut could provide a groundbreaking option for treatment, New Scientist reported.

There are four blood types: A, B, AB and O. Even though the red blood cells in each type are similar, they have different sugars, or antigens, on the surface of the cells, according to the American Red Cross. Type A blood cells have A antigens, while Type B blood cells have B antigens. Type AB has both A and B antigens, but O has no antigens at all, which makes O compatible with the other main blood types because it's not bringing in any antigens that the new blood won't recognize.

There's also a protein called the RH factor, which when present makes someone's blood type positive, and when not present can make it negative. Blood that is negative can be given to people who have either negative or positive blood, which is why Type O negative blood is the universal donor.

"We knew that those same sugars that are on our red blood cells are also produced on the lining of the gut wall," Withers told New Scientist. His team began searching for enzymes in human feces that had the ability to strip a cell of its sugars because those enzymes likely fed on sugars when they were in the gut.

The scientists learned that the enzymes extract sugars from proteins on the gut wall, called mucins. The sugars in mucins are very similar to the antigens on red blood cells. When the team added the enzymes to Type A negative blood, it ate the antigens, and the blood turned into Type O negative.

Bacteria changing Type A to O blood Interregional Transfusion CRS in Bern, Switzerland.
An employee checks the triaging of blood donations at the Interregional Transfusion CRS in Bern, Switzerland. A new technique to turn Type A blood into Type O could allow for more people to get blood when they need it. DENIS BALIBOUSE/REUTERS

"This technique could broaden the utility of the current blood supply because O type blood can be donated to anybody," Steve Withers told New Scientist. This new method could mean that people in areas with low resources, such as rural areas or places facing war, could transform available blood into the blood that anyone could use.

Similar processes are currently used to change blood, but this new method is 30 times faster. The team still needs to test the enzymes further to make sure there are no unintended consequences before using this technique in clinical settings.