Researchers have successfully changed the blood type of three donor kidneys in a game-changing discovery that could significantly increase the chances of transplant patients waiting to find a match.
The development could increase the number of kidneys available for transplant, particularly in ethnic minorities who are less likely to find a match, scientists say.
A kidney from a person with blood type A cannot be transplanted into a person with blood type B, and vice versa.
But changing the blood type to universal O would allow for more transplants, as it can be used for people with any blood type.
Researchers at the University of Cambridge used a normothermic perfusion machine – a device attached to a human kidney to allow oxygenated blood to flow through the organ to better preserve it for future use – to flush enzyme-filled blood through a deceased donor’s kidney.
The enzyme removed the blood type markers lining the kidney’s blood vessels, causing the organ to become type O.
Serena Macmillan, a PhD student at the University of Cambridge, said: “Our confidence was really boosted after we applied the enzyme to a piece of human kidney tissue and very quickly saw that the antigens were removed.
“After that, we realized that this process was possible, and we just had to scale up the project to apply the enzyme to full-sized human kidneys.
“By taking a B-type human kidney and pumping the enzyme through the organ with our normothermic perfusion machine, we saw in just a few hours that we had converted a B-type kidney to an O-type kidney.
“It’s very exciting to think about how this could potentially impact so many lives.”
People from ethnic minorities often wait a year longer for a transplant than white patients, so the research may be particularly important for them, experts say.
People from minority communities are more likely to have type B blood, and due to low donation rates, these populations are in short supply of kidneys.
In 2020-2021, just over 9% of total organ donations in the UK came from black and minority ethnic donors, while black and ethnic minorities make up 33% of the kidney transplant waiting list.
Now the researchers need to see how the newly changed O-type kidney will react to the patient’s normal blood type under normal blood supply.
The machine allows them to do this before testing on humans, as they can take kidneys that have been changed to type O and inject different blood types to control how the kidney might react.
Professor Mike Nicholson, professor of transplant surgery at the University of Cambridge, said: “One of the biggest restrictions on who can receive a donor kidney is that you have to be blood type compatible.
“The reason for this is that your cells have antigens and markers that can be either A or B.
“Your body naturally produces antibodies against those you don’t have.
“Blood grouping is also determined by ethnicity, with ethnic minority groups more likely to have the rarer type B.”
Dr Aisling McMahon, chief executive of research at Kidney Research UK, said: “The research that Mike and Serena are doing could be a game changer.”
After testing reintroduction of other blood types, the team will look at how this approach could be used in a clinical setting.
The study, funded by the charity Kidney Research UK, is due to be published in the British Journal of Surgery in the coming months.
