Britain’s leading leukaemia charity has developed a painless way to test whether someone is a match for a bone marrow transplant.
The Anthony Nolan Trust’s saliva DNA kit will allow doctors to match donors and patients without having to take blood samples.
There are 1,400 people waiting for a bone marrow transplant, which is often their last chance of survival. Most of them are suffering from leukaemia, auto-immune diseases and various blood disorders.
Until now the only way to comprehensively test tissue-type has been to take a blood sample, and doctors believe this has deterred many people from registering.
The new saliva test will allow people to place their details on a bone marrow register from home, rather than needing to attend a doctor’s surgery or a recruitment drive. They simply spit into a test tube and then post it back to the Trust, where specialists will analyse the DNA to look for potential matches. Only 0.5ml of saliva is needed for the test.
The Anthony Nolan Trust has been piloting the saliva kits since December 2009 and more than 5,000 people joined the register using the new method. The charity hopes the new test will eventually double the number of people who sign up each year.
Some donor registries in the United States have begun to use mouth swabs to test for tissue compatibility but the Anthony Nolan Trust says its new saliva test is more reliable because it has a longer shelf life.
The tests have been developed by DNA Genotek, a Canadian firm which has found a way of preserving saliva so that the DNA samples can be held for up to two months at room temperature.
“Saliva gives large, intact DNA fragments just like you find in blood,” explained Alasdair McWhinnie, a research scientist at Anthony Nolan. “But the problem with blood is that you generally have to store it in a refrigerator or freezer if you need it for more than a couple of days.”
As well as enabling people to register from home, the saliva tests should make it much easier to organise donors within scattered families. About 30 per cent of patients in need of a bone marrow transplant are able to find a donor through family or relatives. Previously doctors would need to travel to those relatives or organise a day where they all get together to take blood samples.
There are also hopes that the new saliva tests will encourage more black and Asian people to sign up to the transplant registers.
Black and ethnic minority patients are much less likely to find a bone marrow match because they are woefully underrepresented on the two national bone registries, run by the Anthony Nolan Trust and by the NHS.
While a white person has a one in three chance of finding a donor, Asian and black patients have just a one in 125,000 chance. According to the Afro-Caribbean Leukaemia Trust, of the 690,000 people on the two registries there are just 25,000 black and 12,600 Asian donors.