Should further study validate these findings, clinical laboratories managing hospital blood banks would be among the first to benefit from an abundance of universal donor blood
In a surprising outcome for microbiome research, scientists at the Technical University of Denmark (DTU) and Sweden’s Lund University discovered that the bacteria Akkermansia muciniphila, which resides in the human gut, produces enzymes that can be used to process whole blood in ways that could help produce type-O blood. This “universal” blood type can be given to patients during transfusions when other blood types are in short supply.
Receiving the wrong type of blood via a transfusion could result in a fatal reaction where the immune system launches an attack on foreign antigens. As blood bankers and clinical laboratory scientists know, the A antigens in type A blood are not compatible with the B antigens in type B blood. Type-O blood completely lacks these antigens, which explains why it can be used for individuals of any blood type.
The DTU/Lund discovery—still in its initial stages of development—could eventually give blood bankers in hospital laboratories a way to expand their supply of universal type-O blood. Although individuals with type-O blood are universal donors, often the available supply is inadequate to meet the demand.
“For the first time, the new enzyme cocktails not only remove the well-described A and B antigens, but also extended variants previously not recognized as problematic for transfusion safety,” said Maher Abou Hachem, PhD, Professor of Biotechnology and Biomedicine at DTU, one of the authors of the study, in a news release.
Discovering a way that ensures any blood type can donate blood for all blood types could increase the supply of donor blood while reducing the costs and logistics affiliated with storing four separate blood types. Additionally, the production of a universal blood type using gut microorganisms could reduce the waste associated with blood products nearing their expiration dates.
Whole blood must be used within 42 days after being collected. Having more units of the universal donor blood type would be extremely beneficial in how blood banks manage their blood supply and may revolutionize transfusions. The scientists published their findings in the journal Nature Microbiology titled, “Akkermansia Muciniphila Exoglycosidases Target Extended Blood Group Antigens to Generate ABO-Universal Blood.”
“We are close to being able to produce universal blood from group B donors, while there is still work to be done to convert the more complex group A blood,” said Maher Abou Hachem, PhD (above), Professor of Biotechnology and Biomedicine at DTU in a news release. “Our focus is now to investigate in detail if there are additional obstacles and how we can improve our enzymes to reach the ultimate goal of universal blood production,” he added. Hospital clinical laboratories that manage blood banks will be among the first to benefit from this new process once it is developed and cleared for use in patient care. (Photo copyright: Technical University of Denmark.)
Creating Universal Donor Blood
The bacterium Akkermansia muciniphila is abundant in the guts of healthy humans. It produces valuable compounds, and it is able to break down mucus in the gut and can have significant, positive effects on body weight and metabolic markers.
“What is special about the mucosa is that bacteria, which are able to live on this material, often have tailor-made enzymes to break down mucosal sugar structures, which include blood group ABO antigens. This hypothesis turned out to be correct,” Hachem noted in the DTU news release.
“Instead of doing the work ourselves and synthesizing artificial enzymes, we’ve asked the question: What looks like a red [blood] cell surface? The mucus in our gut does. So, we simply borrowed the enzymes from the bacteria that normally metabolize mucus and then applied them to the red [blood] cells,” Martin Olsson MD, PhD, professor of hematology and transfusion medicine at Lund University, told Live Science. “If you think about it, it’s quite beautiful.”
The researchers successfully identified long strings of sugar structures known as antigens that render one blood type incompatible with another. These antigens define the four blood types: A, B, AB and O. They then used a solution of gut bacteria enzymes to remove the sugar molecules present on the surface of red blood cells (RBCs).
“We biochemically evaluated 23 Akkermansia glycosyl hydrolases and identified exoglycosidase combinations which efficiently transformed both A and B antigens and four of their carbohydrate extensions,” the study authors wrote in Nature Microbiology. “Enzymatic removal of canonical and extended ABO antigens on RBCs significantly improved compatibility with group O plasmas, compared to conversion of A or B antigens alone. Finally, structural analysis of two B-converting enzymes identified a previously unknown putative carbohydrate-binding module.”
“Universal blood will create a more efficient utilization of donor blood, and also avoid giving ABO-mismatched transfusions by mistake, which can otherwise lead to potentially fatal consequences in the recipient. When we can create ABO-universal donor blood, we will simplify the logistics of transporting and administering safe blood products, while at the same time minimizing blood waste,” Olsson said in the news release.
Future Progress
The researchers have applied for a patent for the enzymes and their method of enzyme treatment. The two educational institutions hope to make further progress on this joint project over the next three years. They eventually hope to test their theory in controlled patient trials and make it available for commercial production and clinical use.
More research and clinical studies are needed to prove the effectiveness of this discovery. Clinical laboratory professionals—particularly those who manage hospital blood banks—will want to follow DTU’s research. It could someday lead to the availability of a more abundant supply of universal donor blood for transfusions.
—JP Schlingman
Related Information:
Enzymes Open New Path to Universal Donor Blood
Gut Bacteria Can Help Create Artificial Group O Blood
Universal Donor Blood Significantly Closer Thanks to Enzymes Found in Gut Bacteria
A Gut Bacteria Could Hold the Key to Universal Blood, Revolutionizing Transfusion Medicine