There must be some sort of confusion:
Regarding your first statement: The match of stem cells has nothing to do with AML Leukemia or any other disease that a stem cell transplant is used to treat and I wasn't trying to make that link.
As stated on the Donor Bank website, you are more likely to find a close enough match from someone with your ethnic background. That seems to go against your point that "inherited traits follow random rules". Why would finding an appropriate match be more likely within your ethnic background if inherited traits follow random rules? For me and my friend, the close enough match was outside of the family. The likelihood of finding a match within your family is 30% because you received different combinations of your parent's ethnic backgrounds. I guess that would follow the random rule but at the core it would appear "race" (or biological element) plays a role.
While you are correct you can find an HLA match within different geographic/ethnic groups the likelihood of finding a good match within different geographic/ethnic groups is not that high.
https://www.nejm.org/doi/full/10.1056/NEJMsa1311707 The study shows rates of finding suitably HLA-matched grafts in the NMDP adult-donor registry, with donor availability taken into consideration as follows:
"Most patients will have a 7/8 or 8/8 HLA-matched unrelated adult donor available in the registry. The likelihood of finding an available 8/8 HLA-matched donor is 75% for white patients of European descent (hereafter referred to as white Europeans) but only 46% for white patients of Middle Eastern or North African descent. The likelihood of finding an 8/8 HLA-matched adult donor for other groups is lower and varies with racial and ethnic background. For black Americans of all ethnic backgrounds, the probabilities are 16 to 19%; for Hispanics, Asians, Pacific Islanders, and Native Americans, they range between 27% and 52%."
At the core it would appear "race" (or biological element) plays a role.
This is a good opportunity for me to encourage folks (especially folks of various ethnic groups) to register to be a donor. A simple blood test can put you on the bank and if you get a call, it takes a few days and you can save a person's life. While I had my stem cells harvested, I did my taxes. It isn't that hard!
https://bethematch.org/support-the-cause/donate-bone-marrow/join-the-marrow-registry/
I'm not clear on your first comment, but I think I understand where the confusion is.
I was not referring to HLA in the sole context of stem cell replacement. As you know, HLA matching refers to the antigens of the human leukocyte antigen (HLA) system and presents a major barrier to acceptance of transplants. The medical community is still figuring out which parts of the HLA system can be ignored and which are critical to acceptance of foreign cells from another living organism. In the beginning, the assumption was that each mismatch for HLA antigens had equal weight. Research in the context kidney transplants has shown that we can pretty much ignore HLA-A, that HLA-B is important, but HLA-DR is critical and responsible for most rejections.
Depending on the transplant procedure, we can get away with greater mismatch. To complicate this, blood transfusions (and multiple pregnancies) are known to create HLA sensitivites when recipients have developed antibodies to several HLA molecules, making finding matches even that more difficult because the matches need to be almost perfect. When it comes to stem cell transplantation the margin for error is much less, than say transplanting a kidney. The gold standard is an HLA identical donor, but finding donors with a single-allele mismatch has worked pretty well.
Finally, I do want to clarify that there are many more combinations than I wrote above (I over simplified it). When you refer to 7/8 or 8/8 you are referring to matching HLA -A, -B, -C, and DRB1 between donors. When we are referring to 9/10 or 10/10 we are adding HLA -DQB1 to the mix.
Race v. Ethnicity v. Family
Based on what you wrote, I assumed we all understood that Race is not the same as ethnicity. My statement, Race has no scientific validity given the lack of genetic diversity between 1 individual and another from a different so-called race and merely a social construct attacks the concept that Race is an anachronism from days when we all believed the earth was flat. White/Caucasian, Black/Negro, Brown/Hispanic, Red/Native-American, Yellow/Asian are too imprecise and too broad of categories that do more harm than good and we (
folks that understand the earth is a sphere and can put humans into space) should replace the concept with more precise definitions that are driven by socioeconomic considerations when referring to social and political issues.
Ethnicity is much more precise and takes into consideration "culture" of people in a specific geographic region, including their language, heritage, religion and customs. Members of ethnic groups tend to conform to many of the same practices. The biology of ethnicity does have a scientifically valid role in both biological research and societal issues.
Family is a finite subset of ethnicity, but can implicate multiple ethnic groups as a result of cross-breeding between ethnic groups, thus, it deserves its own status in both science and social research.
The concept of "socioeconomics" to define groups takes into account social factors, such as, ethnicity and community participation and economics. Economic status is actually pretty darn important and it get's virtually ignored when we get lazy and use terms like White, Black, Asian. When we view various social issues through a socioeconomic lens we strip away irrelevant factors and are in a much better position to properly analyze the problem. The failure of the author/reporter/editorializer of the original article cited didn't do this, which is why I said his article lacked research and was lazy reporting.
Ethnicity, Family and HLA
Coming full circle, yes there is a biological significance to finding HLA matches starting at the family and then moving up the ethnic chain as various ethnic groups will have related family connections and greater chances that HLA factors will have recombined into the needed combination for the individual in need. So, I second what you wrote: