Although researchers began performing blood transfusions in the 1600s, ABO blood groups were, unfortunately for patients, not discovered until 1901.1 Despite the decades of study that followed, scientists are still working out why blood types exist in the first place.

     Alex Rowe wears a grey sweater and rests her head on her hand.
Alex Rowe studies host-parasite interactions to better understand factors that contribute to the severity of malaria.
Graham Stone

“There’s lots of evidence that ABO genotype can influence a whole variety of infectious diseases,” said Alex Rowe, a malaria researcher at the University of Edinburgh. For example, Rowe and others demonstrated that people with type O blood develop severe malaria symptoms less often because infected type O red blood cells (RBCs) are less likely to form large clumps—called rosettes—with uninfected RBCs, which then block small blood vessels and damage organs.2

However, Rowe doesn’t think malaria drove the evolution of different blood types. While the timelines are still somewhat contentious, many researchers believe Plasmodium falciparum, which causes the vast majority of malaria deaths, only jumped from gorillas to humans about 10,000 years ago.3 ABO blood groups on the other hand, likely evolved about 20 million years ago.4

The association of blood groups with disease susceptibility goes far beyond malaria. ABO antigens are found not just on RBCs, but also on white blood cells and most epithelial cells, including those lining the gastrointestinal tract. Indeed, ABO types are associated with different levels of susceptibility to many non-RBC infections, including cholera, tuberculosis, hepatitis, and Helicobacter pylori.5

“Some of the infectious diseases going back into human ancestry millions of years are likely to have been the selective pressure that led to the evolution of the ABO system,” said Rowe. Currently, however, it’s not known exactly which disease—or diseases—is the culprit.

 

What makes you curious? Submit a question for us to answer in future “Just Curious” columns.

Submit a Question

  1. Bertsch T, et al. Clin Lab. 2019;65(6).
  2. Rowe JA, et al. Proc Natl Acad Sci U S A. 2007;104(44):17471-17476.
  3. Sharp PM, et al. Annu Rev Microbiol. 2020;74:39-63.
  4. Ségurel L, et al. Proc Natl Acad Sci. 2012;109(45):18493-18498.
  5. Abegaz SB. Biomed Res Int. 2021;2021:6629060.