What Are Its Implications of the Blood Group Breakthrough

Blood transfusion may never be the same again if a discovery by Danish researchers is proved safe and effective in humans. Researchers at the University of Copenhagen have used newly discovered enzymes to eliminate the incompatibility of blood groups A, B and AB by converting these blood groups into the universal donor group O.

The discovery raises hope that shortages of blood in blood banks for transfusions may finally be done away with. Compatibility of blood groups is a problematic issue that has to be faced by hospitals on a daily basis. If the donor's blood type does not match with the recipient, a potentially fatal immune reaction can be triggered.

In order to avert this possibility, cross-matching of blood groups of the donor as well as the recipient are undertaken before any transfusion can proceed. There are two major blood group systems in man, the ABO system and the Rh system named after Rhesus monkeys in which it was first discovered.

The International Society of Blood Transfusion recognizes 29 blood group systems in man. But the ABO system is by far the most important one in human blood transfusion.

The blood cells of people with group type A and B contain immune cells called antigens. People with AB blood group contain both types of antigens and hence this blood group is called the universal recipient. The O blood group does not have any antigens and is incapable of exciting immune cells; thus becoming a universal donor.

The antigens in type A and B are capable of causing other immune calls to develop antibodies if incompatible blood is transfused. More specifically Acute Hemolytic Transfusion Reaction or HTR occurs triggering a cascade of immune reaction, which might ultimately prove fatal.

Unfortunately blood cross-matching relies on technology, which can come a cropper on many occasions. In emergency conditions like massive blood loss due to trauma, a huge amount of blood is required, which may not always be available.

However Danish researchers seem to have overcome this problem by using enzymes to nullify the effect of A and B antigens thereby converting these blood groups into type O or the universal blood group. In effect this means that every individual may one day donate blood without worrying if the type matches perfectly with the recipient.

The details of their research are published Sunday in the online edition of the journal Nature Biotechnology.

Led by Dr. Henrik Clausen of Harvard Medical School and the University of Copenhagen, the researchers hunted for bacteria and fungi that could neutralize the antigens found in A and B blood groups. Their search culminated with the finding of bacterial enzymes called glycosidases, which could target and remove the antigens or sugar molecules.

The researchers found two enzymes that could remove these molecules. The first one in a bacterium called Bacteroides fragilis targets the B antigen, while the other, from Elizabethkingia meningosepticum removes the A antigen.

"The enzymatic conversion processes we describe hold promise for achieving the goal of producing universal RBCs, which would improve the blood supply while enhancing the safety of clinical transfusions," the researchers said.

This is not the first time researchers have attempted to convert A and B blood groups into the universal donor type. In the 1980s Jack Goldstein of the New York Blood Center had isolated an enzyme from coffee beans that could convert B blood type into O. However the purified product was unable to entirely eliminate the antigen thus preserving the danger of an immune reaction.

A company called ZymeQuest in North Andover holds the patents for Goldstein's research and is also associated with the current Danish one. If the technique proves effective then many lives could be saved in time.

Reacting to the development, Dr. Richard Benjamin, chief medical officer at the American Red Cross said the group was looking forward to clinical data on the new findings.

"The Red Cross is very interested in and supports this science and looks forward to seeing the clinical data on this," he added. "We're always in a shortage."

There are many unknowns to this research. For example it is not clear if the enzymes would trigger other immune reactions in the red blood cells. Currently just 5 percent of the population is thought to be donating blood. This is not enough to cope with the high demand.

source:www.newslocale.org