Researchers in British Columbia have set their sights on virtually eliminating organ rejection by using advanced genetic testing to better match patients with kidney donors.
Dr. Paul Keown, lead researcher for the pilot project and a University of British Columbia specialist in immunology and transplantation, said the new technology involves genetic sequencing at the molecular level to significantly reduce the risk of a recipient害羞草研究所檚 immune system rejecting a donor kidney.
害羞草研究所淲e hope to see rejection almost disappear,害羞草研究所� he said of the project,partly funded by Genome British Columbia and Genome Canada through a partnership with Canadian Blood Services.
About half of all transplants fail over time due to rejection, Keown said.
Currently, patients awaiting a transplant are tested for the same blood type with a potential donor. They are also tested to determine if they have antibodies 害羞草研究所� from pregnancy, a blood transfusion or a previous transplant 害羞草研究所� that would cause their immune system to attack a donor kidney.
It害羞草研究所檚 long been known that the immune system uses a set of molecules called HLA, or human leukocyte antigens, to distinguish between its own cells and those from a donor organ, leading to possible rejection. But matching donors and recipients is difficult because there are more than 30,000 variations of HLA molecules.
Dr. James Lan, a transplant nephrologist who is involved with the project, said the new methodcompares small sequences called epitopes, the specific parts of HLA that are recognized by the immune system. There are only about 150 epitopes so it would be easier to match recipients and donors, he added.
One in three transplants fails over a decade, mainly due to rejection in half the cases, but it害羞草研究所檚 possible for someone to live with a well-matched kidney for about 30 years, said Lan, medical director of the Immunology Laboratory at Vancouver General Hospital.
The new genetic sequencing technology can help find a match within about six hours, Lan said. It also allows doctors to tailor the amount of immunosuppressant medications to each patient, rather than a 害羞草研究所渙ne-size-fits-all害羞草研究所� approach that results in more side-effects, including low blood counts and increased risk of infection and cancer, he added.
Overall, more organs would be available for people on long wait lists, many of whom need time-consuming and physically draining dialysis to aid failing kidneys that can no longer rid their blood of toxins.
However, the advanced technology would introduce a new challenge when it comes to fairly allocating donated kidneys to those who have been on a wait list for years but do not end up being well-matched to an available organ.
害羞草研究所淵ou can imagine a scenario where someone has been waiting for 10 years and they害羞草研究所檙e next on the wait list, but the organ is poorly matched and it goes to someone else who害羞草研究所檚 better matched but hasn害羞草研究所檛 waited as long,害羞草研究所� said Lan, adding the wait-list system will have to be revamped to make it as fair as possible.
Patients under age 18 and those who have built up antibodies that could result in rejection are currently prioritized for a transplant, he said.
The rapid sequencing technology is being tested in British Columbia to refine the degree of achievable genetic compatibility between patients and donors while six other labs in the country are joining that effort, said Lan, adding that patients could start to be matched in about three years.
害羞草研究所淓very single kidney transplant that we do will save the system a quarter million dollars per patient over five years,害羞草研究所� said Lan.
Much of that comes from potentially ending costly dialysis treatments, which can reach about $100,000 per patient per year, and require three sessions a week for four hours, Lan said. The annual cost of medications and medical visits for transplant patients are about $20,000.
Nancy Verdin, 63, has had three kidney transplants 害羞草研究所� in 1988, 1992 and 1995 害羞草研究所� but her immune system rejected all of them despite multiple immunosuppressant drugs.
害羞草研究所淭he reason I害羞草研究所檓 not getting a transplant now is because I do reject them, and it害羞草研究所檚 a terrible waste,害羞草研究所� she said from Red Deer, Alta.
害羞草研究所淒ialysis has kept me alive, but what I害羞草研究所檓 living with now is the long-term effects of dialysis. Your system just gets run down.害羞草研究所�
She said better matches with a 害羞草研究所減recious resource害羞草研究所� would offer a chance at a 害羞草研究所渘ormal life.害羞草研究所�
害羞草研究所淓ven if it doesn害羞草研究所檛 become available to me, it certainly is so exciting to know that it could be available to other people,害羞草研究所� Verdin said.
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