Morphing Blood
I try to give blood as often as possible. When I’m working at a big client, they usually have a regularly scheduled blood donation day every 3-4 months, in which I can usually participate even as a consultant. It’s a practice I started right after September 11th, 2001, when the company for which I was working at the time sponsored its own blood bank day in Massachusetts. Whenever I go in, I do often wonder where my donated blood might go, and how it might be used to save someone’s life. My blood type is fairly common among the US population, but still, I’m not a universal donor (type O), which means, to some people, my donation is useless.
However, ZymeQuest Inc., a biotechnology company in Beverly, MA, might have come up with an answer for this problem with blood typing: convert all donated blood into type O. In an article entitled, “Conversion makes all blood type O,” author Jennifer Curtaro explores this new technique and how its application to donations can change the way blood is currently inventoried by banks.
A human’s blood type is determined by sugar molecules on the surface of their red blood cells. One type of sugar is carried by type A blood, another is carried by type B blood, and those who have both are type AB blood. O type blood lacks any of these sugars, and represent about 40% of the population.(1) If the immune system can’t match the sugars on the surface of cells to what it believes the body should be carrying (e.g. an A donor gives to a person with B type blood), then it attacks the foreign cells and causes severe illness, hence why it’s so important to be sure that people get the proper type of blood. However, because the O blood type lacks any of these sugars, the immune system does not defend against it regardless of the patient’s blood type, making it suitable for transfusion to anyone.*
Henrick Clausen, scientific consultant to ZymeQuest and professor of molecular medicine at the University of Copenhagen in Denmark, says the biotech company employs a process using bacteria enzymes to remove the distinctive A and B sugars off of the surface of red blood cells. A proprietary device built by ZymeQuest then washes the red blood cells with a saline solution to remove the enzymes and sugars, resulting in conversion. The device can simultaneously produce 8 units of blood of 500ml each. (2)
The most difficult part of the process is finding the enzyme specific enough to remove only those sugars that uniquely identify types A, B or AB blood. ZmeQuest had obtained rights to intellectual property that dates back 25 years, when a researcher at the New York Blood Center discovered he could use enzymes from unroasted green coffee beans to cut off B-type sugar off of blood cells. However, this ended up using an inefficient process to convert the blood, and the ZymeQuest team abandoned it about eight years ago to find an enzyme that would be less costly to use.
They found the key to their process and are now moving forward with early stages of phase 2 clinical trials, according to the chief financial officer Tom Fitzgerald, who also projected that it would be about three to four more years before the process comes to market.
Before those four years are over, the company has some obstacles it will have to deal with as well. Aside from the potential cost of the process outweighing its benefit, the current process only wastes about 3% of all donated blood, according to the 2005 Nationwide Blood Collection and Utilization Survey Report. And people like Steve Sloan, director of pediatric transfusion medicine at Children’s Hospital Boston, say that there are risks that modified blood cells could cause unexpected problems since they’d been tainted by an artificial process. In theory, any of these problems should come out in clinical trials, but as we found out in last Friday’s post, participants should be carefully screened to ensure they are not tainting the process by engaging in additional studies.
Though I can understand the pitfalls of using an artificial process, I can see its benefits too, especially for extraordinary circumstances. I remember what propelled me into donating after September 11 was the American Red Cross’ call for donated blood to help in time of crisis. Though the “normal” process might only waste 3% of donated blood, I wonder how much blood was wasted during the aftermath of that day? How many people could have benefited from the extra blood? For that matter, could this process have a greater impact worldwide, where donations might be more sparse and universal donor blood types might be more coveted?
What are your thoughts?
(1) See “Conversion makes all blood type O,” Jennifer Curtaro, Boston.com, March 24, 2008, p1.
(2) See (1)
* Blood types also have positive and negative subtypes, but that is beyond the scope of this discussion.
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