Blood Test To Detect Organ Transplant Rejection
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25 September 2010
A simple blood test can now help doctors in identifying the clues of transplant rejection—a feat that could pave the way for a non–invasive alternative for diagnosing organ rejection before damage occurs, says a new study.
The technique could help the 40 per cent of heart transplant recipients who experience an acute episode of rejection in their first year after transplantation.
Usually, in case organ function drops, a small piece of tissue will be removed and checked for rejection.
But many times, the organ may already be damaged by the time doctors spot a problem.
A simple blood test for the proteins involved in the inflammatory response of rejection could provide the answer, said Adul Butte at Stanford University School of Medicine in California.
To identify the protein markers involved in organ rejection, Butt and his team used a publically available repository that documented changes in mRNA levels – the molecules that instructs cells to make proteins – during organ rejection.
These changes gave the team clues about which proteins appear in the blood during rejection.
From 45 protein candidates, the team zeroed in on 10 that could be identified by tests already used in a clinical setting.
Using blood samples from 39 kidney and 63 heart transplant patients they found three proteins which reliably increased during an acute rejection.
According to Minnie Sarval, co–author of the study, the test could be used to adjust the levels of immunosuppressant drugs administered – increasing them only if rejection is imminent – thus minimising side–effects.
"It could also potentially prompt doctors to conduct a biopsy [only] if necessary rather than biopsying straight away," New Scientist quoted her as saying.
More research will show whether these diagnostic markers can predict an acute episode of rejection before any change in organ function.
"Identifying a protein marker that is elevated in the blood before rejection damage could represent a significant advance which could enable early intervention with treatment. Their next challenge would be to examine whether patients treated on the basis of this test do better than those who do not have the benefit of such testing and who have to wait until organ damage occurs before immunosuppressant treatment is increased," said Steven Sacks at the centre for transplantation at King’s College London.
The team is now planning clinical trials and hope their test will be available within three to five years.