Kidney blood type changed in ‘game changing’ first by University of Cambridge researchers

Scientists have managed to change the blood type of transplant kidneys - in a breakthrough they say could be "game-changing" in cutting waiting times for patients from minority groups.

Experts say that people from ethnic minorities often wait a year longer for a transplant than white patients.

Researchers at the University of Cambridge managed to change the blood type of three kidneys to the universal O type - meaning that anyone could take that kidney, rather than being restricted to the A or B types.

The researchers used a normothermic perfusion machine - a device which connects with a human kidney to pass oxygenated blood through the organ to better preserve it for future use - to flush blood infused with an enzyme through the donor kidney.

The enzyme removed the blood type markers that line the blood vessels of the kidney, which led to the organ being converted to O type.

"By taking B type human kidneys and pumping the enzyme through the organ using our normothermic perfusion machine, we saw in a matter of just a few hours that we had converted a B type kidney into an O type,” said Serena MacMillan, a PhD student at the University of Cambridge.

She added: "It's very exciting to think about how this could potentially impact so many lives."

There are hopes that the breakthrough could improve transplant rates and cut waiting times, particularly for people from ethnic minority groups.

People from such groups are more likely to have B type blood and with current low donation rates from these populations, there are not enough kidneys to go around.

Dr Aisling McMahon, executive director of research at Kidney Research UK said the research was “potentially game-changing."

Now the researchers need to see how the newly changed O type kidney will react to a patient's usual blood type in their normal blood supply.

The machine allows them to do this before testing in people, as they can take the kidneys which have been changed to the O type, and introduce different blood types to monitor how the kidney might react.

Who could this breakthrough benefit?

People from ethnic minority groups often wait a year longer for a transplant than white patients, and so the study could have particular implications for them, experts say.

People from minority communities are more likely to have B type blood and with current 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 minority ethnic donors while black and minority ethnic patients make up 33% of the kidney transplant waiting list.

The hope is that if the issue of matching blood types becomes a thing of the past, many more transplants could be carried out, and many more lives saved.

What do transplant patients say?

Patients who stand to benefit are already looking at the breakthrough as an opportunity for "a second chance at a healthy life".

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 that she would need a transplant, but she might have to wait double or even triple the time for a kidney than a white person.

Consultants estimated she might have to wait between six to 10 years to receive one.

Ayesha said: “They explained that because of my ethnicity my wait for a deceased donor will be longer than for a white person. The reason being my background – being the Muslim community and other faiths and cultures often don’t agree to be organ donors.

“I feel sad at the thought of waiting so long for a transplant. I understand a transplant isn’t a cure, but it would make my body a lot stronger and give me a second chance at a healthy life.”

She added: “Even after the law change so everyone was automatically made an organ donor, many people decided to opt out. The research will offer so much hope to minority groups still waiting for a transplant and could help to save many lives.

“Convincing communities that research such as this and organ donation is beneficial is so crucial to improving and saving lives.”

What's the next stage?

Now the researchers need to see how the newly changed O type kidney will react to a patient’s usual blood type in their normal blood supply.

The machine allows them to do this before testing in people, as they can take the kidneys which have been changed to the O type, and introduce different blood types to monitor how the kidney might react.

Prof Mike Nicholson, professor of transplant surgery at the University of Cambridge said: “One of the biggest restrictions to who a donated kidney can be transplanted to is the fact that you have to be blood group compatible.

“The reason for this is that you have antigens and markers on your cells that can be either A or B. Your body naturally produces antibodies against the ones you don’t have.

“Blood group classification is also determined via ethnicity and ethnic minority groups are more likely to have the rarer B type.”

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