New Discovery-Blood Processing Machine.

Editor: Khushboo Pathak     
                Reference: Nature Biotechnology

When a patient is rushed to hospital with a gunshot wound and must get to the operating theatre immediately and need a blood transfusion – but what is your blood group? Doctors and nurses are fighting the clock to save the patient and, in a moment of rush, the wrong bag of blood is taken. Blood mix-ups, though rare, are still one of the most feared mistakes in transfusion medicine.

In future, it may not matter, thanks to enzymes that scrub antigens from red blood cells, turning all donated blood into group O – which can be given safely to anyone. The blood cells of people with group A and B blood contain one of two different sugar molecules, which act as "antigens", triggering an immune response. Sugar molecule determines whether the antigen is A or B.

The A and B antigens, which give blood groups their name, are sugars carried on the surface of red blood cells. Human red blood cells can carry one of these antigens, both, or neither; giving rise to four blood groups: A, B, AB and O respectively. People with AB blood have both types of molecule, while those with group O blood have neither. People produce antibodies against the antigens they lack. Because the body's immune system recognizes its own sugar molecules, but sees sugars of another type as foreign invaders. That's why a person with type A blood can't receive a transfusion from someone with type B blood: The type A immune system would attack the new blood as foreign, making the person seriously ill.

 

Because type O blood carries neither of these sugars, it navigates undetected right past the immune systems of type A, B, and AB individuals. For this reason, patients with any blood type can receive blood type O. The blood type O is used in emergency situations when we don't have time to check a patients' blood type.

 

Researchers have created a cheap and simple way to convert all donated blood into group O, the universal group that can be given safely to anyone.

The ZymeQuest's machine, roughly the size of a dishwasher, is a pair of enzymes newly discovered by Henrik Clausen of the University of Copenhagen in Denmark that can cleave sugar molecules from the surface of the red blood cells  and easily transform blood types A and B into the precious blood type O. The molecular machine could theoretically turn any kind of blood into Type O.This device churn out eight units of type O every 90 minutes.

The technique works by using bacterial enzymes to cut sugar molecules from the surface of red blood cells. After a search of 2,500 fungi and bacteria the researchers discovered two bacteria - Elizabethkingia meningosepticum and Bacterioides fragilis - which contained potentially useful enzymes. They found that enzymes from both bacteria were able to remove both A and B antigens from red blood cells. They act like miniature scissors to snip off the sugar molecules thus converting all blood cells to group O.

Elizabethkingia meningosepticum targets the A antigen and Bacterioides  fragilis removes the B antigen.

The discovery could eventually reduce blood shortages and make transfusions safer. The technique potentially enables blood from groups A, B and AB to be converted into group O negative, which can be safely transplanted into any patient. 

Blood processed by ZymeQuest using the sugar-cleaving enzymes is currently in early phase II clinical trials in the United States. If all goes well, the company expects its blood-processing machines to be on the market in Europe in 2011 and in the United States a few years later.