BEIJING, April 2 (Xinhuanet) -- Danish researchers have developed a simple method of converting types A, B, and AB blood into type O, which is a breakthrough to end the shortages of type O blood, the journal Nature Biotechnology said Sunday.

    People in groups A and B have blood containing one of two different sugar molecules which can trigger an immune response, they said. Those in group O have neither of these "antigens," while those in group AB have both. So giving patients the wrong type of blood may result in a severe immune reaction or even death. Only type O is the universal-donor blood that can be given to anyone.

    The team -- led by cellular biologist Henrik Clausen of the University of Copenhagen -- reported in the journal that they isolated bacterial enzymes that safely remove from red blood cells the sugar molecules that provoke an immune reaction in the recipient.

    Previous studies of type O blood produced from type B by a different method have shown it to be safe and effective, and the researchers are now conducting clinical trials with the new product. Those results are expected to be available later this year.

    "Those issues could be largely resolved if there were a universally transfusible blood supply," said Doug Clibourn, chief executive of ZymeQuest Inc. in Beverly, Mass., which is developing the technology.

    ZymeQuest commissioned Clausen to search for new enzymes to convert type A and type B to type O. Clausen and his team sifted through more than 2,500 bacteria and fungi before identifying the two candidates.

    The new enzymes are more potent than previously used ones and, more important, they work at room temperature and neutral pH, which is very good for blood cells, said Dr. Martin Olsson of Lund University in Sweden. In an hour, they remove all the sugar molecules from the surface of red blood cells, after which they can be easily washed away.

    (Agencies)