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含羞草研究社檚 immune system rejecting a donor kidney.
含羞草研究社淲e hope to see rejection almost disappear,含羞草研究社� 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 含羞草研究社� from pregnancy, a blood transfusion or a previous transplant 含羞草研究社� that would cause their immune system to attack a donor kidney.
It含羞草研究社檚 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含羞草研究社檚 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 含羞草研究社渙ne-size-fits-all含羞草研究社� 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.
含羞草研究社淵ou can imagine a scenario where someone has been waiting for 10 years and they含羞草研究社檙e next on the wait list, but the organ is poorly matched and it goes to someone else who含羞草研究社檚 better matched but hasn含羞草研究社檛 waited as long,含羞草研究社� 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.
含羞草研究社淓very single kidney transplant that we do will save the system a quarter million dollars per patient over five years,含羞草研究社� 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 含羞草研究社� in 1988, 1992 and 1995 含羞草研究社� but her immune system rejected all of them despite multiple immunosuppressant drugs.
含羞草研究社淭he reason I含羞草研究社檓 not getting a transplant now is because I do reject them, and it含羞草研究社檚 a terrible waste,含羞草研究社� she said from Red Deer, Alta.
含羞草研究社淒ialysis has kept me alive, but what I含羞草研究社檓 living with now is the long-term effects of dialysis. Your system just gets run down.含羞草研究社�
She said better matches with a 含羞草研究社減recious resource含羞草研究社� would offer a chance at a 含羞草研究社渘ormal life.含羞草研究社�
含羞草研究社淓ven if it doesn含羞草研究社檛 become available to me, it certainly is so exciting to know that it could be available to other people,含羞草研究社� Verdin said.
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