LogFAQs > #882495874

Baardmeester posted...

Then why do people with leukemia need donors of the exact same race. Mixed race leukemia patient have the hardest time to find donors, because they need the exact same mix.

Genetics and the immune system treating unfamiliar matter as a threat. You need to have matches on certain types or rejection is likely. Same with blood... You need an appropriate blood type or bad things happen, but ethnicity does not factor in. It gets more complicated with organs and marrow where genetic markers make the difference between acceptable and rejection.

When it comes to matching human leukocyte antigen (HLA) types, a patient’s ethnic background is important in predicting the likelihood of finding a match. This is because HLA markers used in matching are inherited. Some ethnic groups have more complex tissue types than others. So a person’s best chance of finding a donor may be with someone of the same ethnic background.

Without genetic similarity between the donor and the patient, the new white blood cells will attack the host body. In an organ transplant, the body can reject the organ, but with marrow, the new immune system can reject the whole body.

https://bethematch.org/transplant-basics/matching-patients-with-donors/how-does-a-patients-ethnic-background-affect-matching/

http://content.time.com/time/health/article/0,8599,1993074,00.html

Your genetic markers have to do with common ancestry and the pool of donors. The fact is that these can vary greatly even in related individuals. And many people of the same race may not have similar family history and don't share genetics needed for a transplant.

To find a marrow match for anyone is hard. Even within one's own family, the chances of finding one are only about 30%. According to the World Donor Marrow Association, while two out of three Caucasians find a match, the chances of a patient from another ethnic background can be as low as one in four. Despite rapid improvements in marrow registries around the world, the global registry is still disproportionately represented by the U.S., U.K. and Germany — all predominantly Caucasian countries. For a multiracial person, the chances are usually even worse. Athena Mari Asklipiadis, the founder of the California-based Mixed Marrow, one of the only outreach groups devoted to recruiting mixed race donors, says "the numbers are quite staggering ... People compare it to winning the lottery."

So I don't know exactly what your point is. There are genetic differences between people in the same race. Everyone has a unique genome. Immune systems reject foreign material and for some particular transplants the matches have to be a lot more exact.
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