After you have sent back your swabs to DKMS, we analyse your tissue-type at our laboratory. The test performed determines your blood group and rhesus status and is looking for specific 'markers' that appear on most of your body’s cells, known as HLA tissue markers.
Your tissue type is then entered anonymously into the UK national database with your allocated donor number, which is then linked to the worldwide registries, available to be searched for any patient around the world.
So what exactly are HLA characteristics?
HLA tissue characteristics are much more complex than matching blood types. HLA stands for Human Leukocyte Antigens (characteristics of human white blood cells) and these ‘markers’ identify cells that belong to you. Your body uses this information to determine ‘friend or foe’ and generally the immune system will attack anything not marked as ‘friend’.
There is a great diversity of HLA and the cheek swab is currently tested for up to 10 characteristics. Half are inherited from your mother and half from your father. This means you and your sibling have a 25-30% chance of having exactly the same HLA characteristics. This means that most patients are unable to have a donation from a sibling, and an unrelated donor is required. This donor should ideally be a perfect HLA match.
As HLA types are inherited, the best chance of finding a suitable donor may be with someone of a similar ethnic background. Some people have very diverse tissue types (we currently know of more than 2,500 different HLA versions in the human population) based on their ancestry that can affect their chances of finding a matching donor. The two infographics illustrate the randomness and probability of finding matching donors. This is why your registration counts.