transmutation

Science | Type A blood converted to universal donor blood with help from bacterial enzymes

On any given day, hospitals across the United States burn through some 16,500 liters (35,000 pints) of donated blood for emergency surgeries, scheduled operations, and routine transfusions. But recipients can’t take just any blood: For a transfusion to be successful, the patient and donor blood types must be compatible. Now, researchers analyzing bacteria in the human gut have discovered that microbes there produce two enzymes that can convert the common type A into a more universally accepted type. If the process pans out, blood specialists suggest it could revolutionize blood donation and transfusion.

“This is a first, and if these data can be replicated, it is certainly a major advance,” says Harvey Klein, a blood transfusion expert at the National Institutes of Health’s Clinical Center in Bethesda, Maryland, who was not involved with the work.


People typically have one of four blood types—A, B, AB, or O—defined by unusual sugar molecules on the surfaces of their red blood cells. If a person with type A receives type B blood, or vice versa, these molecules, called blood antigens, can cause the immune system to mount a deadly attack on the red blood cells. But type O cells lack these antigens, making it possible to transfuse that blood type into anyone. That makes this “universal” blood especially important in emergency rooms, where nurses and doctors may not have time to determine an accident victim’s blood type.