Scientists learn to convert blood types, may ease shortages

Scientists learn to convert blood types, may ease shortages
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First Published: Mon, Apr 02 2007. 03 03 AM IST
Updated: Mon, Apr 02 2007. 03 03 AM IST
Scientists have discovered a way to convert blood to the type that’s almost universally tolerated, promising to ease the risk of getting the wrong transfusion and ending blood shortages that often rack hospitals.
A group of 16 scientists working with the Beverly, Massachusetts-based biotechnology company ZymeQuest Inc. sifted through enzymes produced by 2,500 bacteria and fungus to find two, one that converts Type A blood to Type O and another that converts Type B to Type 0. The results are published today in Nature Biotechnology.
Shortages particularly of type O are common because donations fluctuate and the need for blood transfusions is rising. More health-care options in developing nations, new technologies in developed countries, and rising incidents of injuries are building demand, the International Federation of Blood Donor Organizations says. Emergency rooms often use type O because they often can’t quickly check a patient’s blood type.
“There’s not enough blood in the system,’’ Henrik Clausen, a professor of cellular and molecular medicine at the University of Copenhagen, said in a telephone interview March 30. “If you could change that, it would be very important.’’ Clausen is among the study’s authors and a consultant for ZymeQuest.
U.S. hospitals often face shortages in winter when donors go on holidays or are ill, according to the American Red Cross, the country’s largest blood supplier. Meanwhile, developing countries collect 40% of the world’s blood yet make up 80 % of the population, according to the international federation.
Transfusion Killers
Blood comes in more than 2 dozen types, with A, B, AB and O the most common. Aside from O, the types cannot be mixed or the blood will clump, and patients can have reactions ranging from heightened blood pressure to kidney damage to death.
“A-B-O incompatibility is one of the top three killers in blood transfusions today,’’ Martin Olsson, a professor in hematology at Lund University in Sweden, said in a March 30 telephone interview. Olsson consults both for the university’s blood center and for ZymeQuest. Others include bacterial infection and adverse immune responses in the lungs.
The bacterial enzymes essentially cut off the molecule on the red blood cells that determine whether it is type A or B. “These types of enzymes are like scissors,’’ Clausen said. “They’re very specific.’’
Douglas Clibourn, ZymeQuest’s chief executive officer, estimated roughly 19 million non-type O transfusions are done annually in the countries in Europe, Asia and the U.S. that the company will target. Blood centers will be better able to manage the supply, and won’t have to shuttle units back and forth to ensure adequate supplies of each kind.
Huge Costs
“The costs associated with that are huge,’’ Clibourn said in a March 30 telephone interview.
ZymeQuest, which is privately held, hopes to commercialize the process, using recombinant gene technology. E. coli bacteria would be reprogrammed with new DNA to produce the enzymes in mass quantities so they would be affordable. ZymeQuest scientists previously had discovered an enzyme in the coffee bean plant that converts type B blood to type O. However, the amount of enzyme needed made the process cost-prohibitive.
Clinical testing is under way. Converted type A blood is in the second of three trials typically needed before a company can seek approval from the U.S. Food and Drug Administration to market a product. The company will supplement already completed phase II trials of type 2 blood converted with coffee bean-plant enzyme with additional information on blood converted with the new enzyme, before moving onto the last phase, Clibourn said.
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First Published: Mon, Apr 02 2007. 03 03 AM IST
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