http://www.digitaljournal.com/life/health/researchers-may-have-discovered-key-to-blood-type-conversion/article/432333

Researchers may have discovered key to blood type conversion

Posted May 2, 2015 by Brian Booker
Researchers at the University of British Columbia are closing in on a major medical breakthrough, having discovered a process for snipping sugars off of A and B type blood cells, making them more similar to the universal type O blood type.
A blood donation
A blood donation
Flickr user warrenski
Researchers have created an enzyme that is capable of trimming sugar antigens off of blood cells. Type O universal blood cells lack antigens on their surface, thus by trimming off antigens, the enzyme essentially converts Type A and Type B blood to Type O.
At this stage, the enzyme is capable of removing most but not all of the antigens. Due to the sensitivity of antibodies in the body, the enzyme cannot be used in a clinical setting until it is engineered to remove all of the antigens, so work remains to be done.
Researchers used directed evolution, which involves inserting mutations into the genes used to control production of the enzyme, and then selecting the mutants that were best able to remove the antigens. In just five generations researchers were able to make the enzymes 170 times more effective.
Different blood types make transfusions difficult because if a patient receives the wrong kind of blood, their body will react and release antibodies to destroy it. Type O blood, however, can be used in every transfusion, thus making it very valuable for medical professionals.
This does not mark the first time that researchers have come close to converting blood types, but it does mark the most affordable and practical process so far discovered.
Blood types complicated but vital for health care
Blood types vary according to the antigens found on red blood cells, and also the antibodies found within the blood's plasma. Antigens are essentially sugars found on the surface of cells (or other microbes) and act as an indicator for the immune system to produce antibodies.
In other words, if you're a Type A patient and receive a Type B transfusion, your body will react to the Type B antigens and produce antibodies to destroy the Type B cells.
To this day doctors are still unsure of exactly why humans have developed different blood types. In certain cases, blood types do appear to provide protection against diseases. For example, people with Type O blood are more resistant to Malaria, while those with Type A blood are more vulnerable.
Type O blood's resistance to Malaria probably explains why it is the most common type of blood. 37 percent of Caucasians have Type O positive blood, while 47 percent of African-Americans and 53 percent of Hispanics have it.
Type O blood can be given to any patient, which is why it is so valuable in the medical profession. Type O patients, however, can only receive transfusions of Type O blood, otherwise antigens in the patient's blood will attack the newly transfused blood cells.
Type AB blood patients, meanwhile, possess cells with both Type A and Type B antigens, but their plasma is free of the antibodies that attack either. This means they can receive any type of donation, but can only donate to other Type AB patients.
There are further complications for each type of blood, with only Type O blood being universally accepted.
In emergency situations, doctors and healthcare professionals are often pressed for time. Testing a patient's blood and then finding the suitable blood for transfusions can waste precious minutes.
Type O blood's universal nature thus makes it very valuable in healthcare, and particularly during emergencies. Due to the high demand for Type O blood, however, blood banks often face shortages.
If researchers can create an economical way to trim off antigens, it could revolutionize the blood transfusion industry.