After a decade of work, researchers are closer than ever to a key breakthrough in kidney organ transplants: being able to transfer kidneys from donors with different blood types from the recipients, which could significantly shorten waiting times and save lives, they say.
A team from institutions across Canada and China has managed to create a “universal” kidney, which can, in theory, be accepted by any patient, reports ScienceAlert.
Their test organ survived and functioned for several days in the body of a brain-dead recipient, whose family consented to the research.
“This is the first time we’ve seen this play out in a human model,” said biochemist Stephen Withers, from the University of British Columbia in Canada. “It gives us invaluable insight into how to improve long-term outcomes.”
Currently, people with type O blood who need a kidney usually have to wait for a type O kidney to become available from a donor. That accounts for more than half the people on waiting lists, but because type O kidneys can function in people with other blood types, they’re in short supply.
While it is possible to transplant kidneys of different blood types, by training the recipient’s body not to reject the organ, the existing process is far from perfect and not particularly practical.
It’s time-consuming, expensive and risky, and it also requires living donors to work, as the recipient needs time to be prepped.
Here, the researchers effectively converted a type A kidney into a type O kidney, using special, previously identified enzymes that strip away the sugar molecules (antigens) acting as markers of type A blood.
The researchers compare the enzymes to scissors working on the molecular scale: by snipping off part of the type A antigen chains, they can be turned into the ABO antigen-free status that characterises type O blood.
“It’s like removing the red paint from a car and uncovering the neutral primer,” said Withers. “Once that’s done, the immune system no longer sees the organ as foreign.”
There remain plenty of challenges ahead before trials in living humans can be considered.
The transplanted kidney did start to show signs of type A blood again by the third day, which led to an immune response – but the response was less severe than would usually be expected, and there were signs that the body was trying to tolerate the kidney.
The statistics surrounding this issue are pretty stark: at the moment, 11 people die waiting for a kidney transplant each day, in the US alone, and the majority of those are waiting for type O kidneys.
It’s a problem that scientists are tackling from multiple angles, including making use of pig kidneys and developing new antibodies. Broadening the number of compatible kidneys these people can have promises to make a significant difference.
“This is what it looks like when years of basic science finally connect to patient care,” said Withers. “Seeing our discoveries edge closer to real-world impact is what keeps us pushing forward.”
The research has been published in Nature Biomedical Engineering.
Study details
Enzyme-converted O kidneys allow ABO-incompatible transplantation without hyperacute rejection in a human decedent model
Jun Zeng, Ming Ma, Ze Tao et al.
Published in Nature Biomedical Engineering on 3 October 2025
Abstract
ABO-incompatible kidney transplantation is widely used to meet the escalating need for organs. Current recipient-centric desensitisation protocols involving antibody depletion through plasmapheresis increase the risk of infections, perioperative bleeding events and costs. Here we present a donor-centric desensitisation protocol, converting type-A kidneys into enzyme-converted O kidneys during hypothermic perfusion to remove the A antigen from the kidneys. An ex vivo model resulted in no antibody-mediated injury. Encouraged by this, an enzyme-converted O kidney was transplanted into a type-O brain-dead recipient with a high titre of anti-A antibody, and no hyperacute rejection was observed. The graft was well tolerated with no evidence of antibody-mediated rejection for 2 days. Antibody-mediated lesions and complement deposition were found starting 3 days post-transplant, coinciding with A-antigen regeneration, and later higher Banff scores, suggesting an immune-mediated response. Single-cell sequencing confirms the elevated expression of accommodation-related genes, suggesting the potential for longer-term tolerance. This study provides a donor-centric organ engineering strategy and has the potential to broaden the reach of ABO-incompatible kidney transplantation, improving the fairness of and access to organ allocation.
See more from MedicalBrief archives:
ABO-incompatible kidney transplants a first for South Africa
Large study identifies new kidney transplant rejection indicators
US pig kidney man ‘doing well’ as transplant trials due to start
Africa’s first incompatible kidney transplant at Groote Schuur