There is a McLeod syndrome specifically known to people with the Kell blood group

[Nicholas Ward]

The McLeod syndrome is responsible for low expression of the Kell antigens.

It makes you wonder if this was a partial inspiration for Endgame?

[dubiousbystander]

blinking in stunned shock. That's just too cool for words!
https://www.ncbi.nlm.nih.gov/books/NBK1354/

[Coolwater]

So, see if I have this straight, please:
The primary blood symptom of a Macleod is acanthocytosis, which is "a form of red blood cell that has a spiked cell membrane, due to abnormal thorny projections." (The blood cells have blades! ) Those thorny cells die faster than the usual smooth kind, which could lead to anemia, except that the MacLeod body then makes a lot of extra red blood cells to make up the difference. (It heals itself!)

And Kell antogens? Antigens are triggers for immune system responses and the Kell antigens are found on the outside of the MacLeod red bloods cells; they are similar to Rh factors and help determine blood type. Most folks don't have the Kell antibodies, but MacLeod often do. If the MacLeod/Kell individual is then exposed to blood that does not have the K antigens, the non-K immune system may develop Anti-K, which attacks the transfused K blood. (Never give non-Kell blood to a MacLeod!). Or, in the words of Wikipedia,

"Allo-antibodies in the Kell... blood group system can cause strong reactions to transfusions of incompatible blood and severe anemia in newborns of Kell-negative mothers."

It's like Rh negative babies with an Rh positive mother: a Kell/MacLeod baby with a more common anti Kell mother, is liable to be still born or die very young. No children for Kells and MacLeods.

Too strange.

[Andrew NDB]

[Nicholas Ward]

[Coolwater]

Amen, brothers.