Many thousands of individuals are affected by cancers and other blood conditions that require a bone marrow or stem cell transplant. In some situations, stem cells can be collected from the patients own blood or marrow and then transplanted back –- a process known as an autologous transplant. More commonly, patients must look for a donor for their transplant.
Who can be a donor
A donor is an individual whose HLA matches the patient. To know more about HLA and why matching is required, read:
A donor within the family
The HLA combination of the patient is inherited, and therefore the chances of a match are highest within the family. An identical twin will have the same genetic makeup as the patient and is a perfect match. Unfortunately, not all patients requiring a transplant have twins. Siblings also have a fairly high chance of a HLA match. The chances of finding a match from among all siblings increase with the number of siblings one has. Chances increase from about 25% with a single sibling to 92% with 10 siblings. Parents can also be a match for their children, and children for parents. Cousins could be a match too, though the chances are lower.
Individuals unrelated to the patient may also have matching HLA. The chances of a match are higher with individuals within the same ethnic community. Communities in which marriages are more often confined within it are more likely to have a higher proportion of matching individuals. To find an unrelated donor, it is often necessary to search for matches in bone marrow donor registries.
Marrow donor registries
Marrow donor registries are databases that store the HLA details of volunteers willing to donate marrow for an individual for a transplant. These databases can be searched for matches for the patient’s HLA combination. Though the chances of finding a match are one in several thousand, tens of thousands of patients have found unrelated donors from within large donor registries.
Many countries and independent organizations maintain large marrow donor registries. These can be contacted for conducting a search for a HLA match. Here are some links:
- USA: National Marrow Donor Program (NMDP)
- Canada: Canadian Blood Services – OneMatch and the Hema-Quebec
- UK: British Bone Marrow Registry and the Welsh Bone Marrow Donor Registry
- Australia: Australian Bone Marrow Donor Registry
- A comprehensive list of Marrow Donor Registries all around the globe is given here at Heal Emru
National Cancer Institute Factpage on Bone Marrow and Stem Cell Transplants. Last accessed on 23 October 2008.