Michelle was able to donate a kidney to her sister Maxine
A pioneering procedure has allowed a British woman to get a new kidney from her sister - even though the organ would normally be rejected.
Maxine Bath had been kept alive by dialysis, and had no matching donors in her family.
However, doctors in Coventry used a technique called "cryofiltration" to remove the immune molecules that cause rejection.
Doctors said it could allow more people to undergo transplants.
A total of 927 kidney transplants from "living donors" took place in Britain last year, although thousands more people remain on waiting lists, because a matching donor cannot be found.
Organ rejection happens when the body recognises the new organ as foreign, and the immune system reacts against it.
The risk can be reduced if the donor organ comes from another family member, and patients will often take drugs for the rest of their lives to 'damp down' their immune response.
However, Maxine, 41, from Wolverhampton, who had been in kidney failure for 15 years, was found to have immune system antibodies against the tissue types of all her family members, which seemed to rule them out as "living donors".
Other ways of removing these antibodies could not be used, as she had low blood pressure, and they could lower it further.
However, the new technique of cryofiltration did not present the same risk, and this is believed to be the first time it has been used to help a patient receive a non-matched organ.
The procedure involves circulating the blood plasma through a machine which heavily chills it, turning proteins and antibodies into a gel-like substance which can then be easily filtered out, before the plasma is re-warmed and returned to the patient.
Race against time
Dr Rob Higgins, a kidney specialist at University Hospitals Coventry and Warwickshire NHS Trust said: "Maxine would have gone blind within two years because of her low blood pressure, if she had not received a new kidney.
"This is another innovative measure we have implemented at the trust which opens the doors of donation for more kidney patients awaiting transplants."
Both Maxine, and her sister Michelle, who was the closest match available in the family, underwent the procedure five times before the transplant took place.
The operation, carried out in November, has already transformed Maxine's life.
She said: "I'm already feeling healthier - I am looking forward to being able to eat food I couldn't have at all before, like nuts and chocolate.
"Rob told me I was the first kidney patient in the world to try this technique which I thought was really exciting - it hasn't sunk in yet."