Researchers at the University of Cambridge have altered the blood type of three donor kidneys which they say could have “major implications” for transplant patients.

The discovery could increase the supply of kidneys available for transplant and could be particularly impactful for people from ethnic minority groups who are less likely to be a match for the majority of donated kidneys and often wait a year longer for a transplant than their white counterparts.

People from ethnic minority communities are more likely to have B type blood, a blood group which currently has low donation rates.

In 2020/21, just over nine per cent of total organ donations came from black and minority ethnic donors whilst black and minority ethnic patients make up 33 per cent of the kidney transplant waiting list.

A kidney from someone with an A blood type cannot be transplanted to someone with a B blood type, nor the other way around.

However, as O blood type can be used for people with any blood group, changing the blood type to the universal O could allow more transplants to take place.

The University of Cambridge's Professor Mike Nicholson and PhD student Serena MacMillan 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 deceased kidney.

The enzyme acted like “molecular scissors” to remove the blood type markers that line the blood vessels of the kidney resulting in the organ being converted to the most common O type.

“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," said MacMillan. "After this, we knew that the process is feasible, and we just had to scale up the project to apply the enzyme to full-size human kidneys."

She added: "By taking B type human kidneys and pumping the enzyme through the organ using our normothermic prefusion machine, we saw in a matter of just a few hours that we had converted a B type kidney into an O type.”

Professor Nicholson said that after successfully shifting the blood group to the universal O type, the research now needs to explore whether this method could be successful in a clinical setting and ultimately carried through to transplantation.

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