Race matters when a patient needs a stem cell or marrow transplant

If you become ill with a blood cancer or other disease that requires a stem cell transplant, here’s an uncomfortable fact: Your race matters. Diversity is a strength in much of life, but it’s a curse when finding a stem cell donor match.

For a successful transplant, donor and recipient must have nearly identical genes regulating certain immune cells. These genes evolved in response to the disease threats people faced long ago. “Tell me where your ancestors lived 500 years ago, and I’ll tell you who your potential donors are,” says Jeffrey Chell, an internist who leads the National Marrow Donor Program, also known as Be The Match.

African Americans have the most diverse genetics because their ancestors have been around the longest and because of intermixing with whites, Native Americans and Hispanics since Africans arrived in the Western Hemisphere. When all of humankind’s relevant genes are considered, there are 10 billion possible combinations. That means that “if your ancestors were on two or three continents,” Chell says, “it’s going to be harder to find a match.”

Genetics make the mathematics difficult for people of color. Cultural traditions, mistrust of medicine and ignorance about the need for donors make it worse.

“I didn’t know anything about bone marrow transplants until I learned that I might need one,” says Anthony Thomas, 49, a financial consultant from Ran­dalls­­town, Md., who has chronic lymphocytic leukemia. Among his African American friends and colleagues, there’s little awareness of the importance of donating, he says, although “you can bet that if Lil Wayne or Beyoncé got leukemia, that would change.”

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