NEW YORK (Reuters Health) - In a report released Sunday, researchers describe the use of newly discovered enzymes to efficiently convert blood types A, B, and AB into O, the universal donor type.

More than two decades ago, researchers began testing the concept of removing blood group antigens to create universal red blood cells, according to the report.

In 2000, findings from a phase II crossover trial showed that type B red blood cells could be converted into type O cells, which then survive normally when given to type A and O individuals. However, the clinical utility of this approach was limited by the large amount of enzymes required for the conversion.

In the present study, reported in the April 1st online issue of Nature Biotechnology, Dr. Henrik Clausen, from the University of Copenhagen in Denmark, and colleagues describe two previously unknown bacterial glycosidase gene families that feature enzymes capable of efficiently removing the A and B antigens. Moreover, the reactions take place at neutral pH and require low levels of recombinant enzymes.

"The enzymatic conversion processes we describe hold promise for achieving the goal of producing universal red blood cells, which would improve the blood supply while enhancing the safety of clinical transfusions," Dr. Clausen and his team conclude.