Scientists have successfully changed the blood type of three donor kidneys in a game-changing discovery that could have a massive impact on patients waiting for a transplant.
The development could increase the supply of kidneys available for transplant, particularly within ethnic minority groups who are less likely to find a match, researchers say.
A kidney from someone with blood type A cannot be transplanted into someone with blood type B, nor vice versa.
However, changing the blood type to the universal O will allow more transplants to take place, as this can be used for people with any blood type.
Researchers from the University of Cambridge used a normothermic perfusion machine – a device that attaches to a human kidney to pass oxygen-rich blood through the organ to better preserve it for future use – to flush blood infused with an enzyme through the deceased donor kidney.
The enzyme removed the blood type markers that line the blood vessels in the kidneys, causing the organ to be converted to type O.
University of Cambridge PhD student Serena MacMillan said: “Our confidence was really boosted after we applied the enzyme to a piece of human kidney tissue and saw very quickly that the antigens were removed.
“After this, we knew that the process is feasible, and we just had to scale up the project to use the enzyme on full-sized human kidneys.
“By taking human B-type kidneys and pumping the enzyme through the organ using our normothermic perfusion machine, we saw within a few hours that we had converted a B-type kidney to an O-type.
“It’s really exciting to think about how this could potentially affect so many lives.”
People from ethnic minority groups often wait a year longer for a transplant than white patients, and so the study may have special implications for them, experts say.
People from minority communities are more likely to have blood type B, and with today’s low donation rates from these populations, there are not enough kidneys to go around.
In 2020/21, just over 9% of total organ donations came from black and ethnic minority donors, while black and minority patients 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 a patient’s normal blood type in their normal blood supply.
The machine allows them to do this before testing on humans, as they can take the kidneys that have been changed to the O type and introduce different blood types to monitor how the kidneys might react.
Professor Mike Nicholson, Professor of Transplant Surgery at the University of Cambridge said: “One of the biggest restrictions on who a donated kidney can be transplanted into is the fact that you have to be blood type compatible.
‘The reason for this is that you have antigens and markers on your cells which can be either A or B.
“Your body naturally produces antibodies against those you don’t have.
“Blood group classification is also determined by ethnicity and ethnic minority groups are more likely to have the rarer B type.”
Dr Aisling McMahon, chief executive of research at Kidney Research UK said: “The research that Mike and Serena are carrying out is potentially game-changing.”
After testing the reintroduction of other blood types, the team will look at how the approach could be used in a clinical setting.
The research, funded by the charity Kidney Research UK, is due to be published in the British Journal of Surgery in the coming months.
Ayesha, from Bury in Greater Manchester, was diagnosed with stage three chronic kidney disease in 1998 when she was pregnant with her first child.
Her kidneys deteriorated rapidly during the pandemic, and she was told she would need a transplant, but she might have to wait twice or even three times as long for a kidney as a white person.
Consultants estimated she might have to wait between six and ten years to get one.
Ayesha said: ‘They explained that because of my ethnicity, my waiting time for a deceased donor would be longer than for a white person.
“The reason is my background – the Muslim community and other faiths and cultures often do not agree to be organ donors.
“I feel sad at the thought of waiting so long for a transplant. I understand that a transplant is not a cure, but it will make my body much stronger and give me a second chance at a healthy life.’
She added: “Even after the law was changed to automatically make everyone an organ donor, many people decided to opt out.
The research will give so much hope to minority groups still waiting for a transplant and can help save many lives.
“Convincing communities that research like this and organ donation is useful is so critical to improving and saving lives.”
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