In a study published in Nature Medicine, a team of Scandinavian scientists explain the mechanisms behind the protection that blood type O provides, and suggest that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population.
It has long been known that people with blood type O are protected against severe malaria, while those with other types, such as A, often fall into a coma and die. Unpacking the mechanisms behind this has been one of the main goals of malaria research.
A team of scientists led from Karolinska Institutet in Sweden have now identified a new and important piece of the puzzle by describing the key part played by the RIFIN protein. Using data from different kinds of experiment on cell cultures and animals, they show how the Plasmodium falciparum parasite secretes RIFIN, and how the protein makes its way to the surface of the blood cell, where it acts like glue. The team also demonstrates how it bonds strongly with the surface of type A blood cells, but only weakly to type O.
Principal investigator Mats Wahlgren, a Professor at Karolinska Institutet’s Department of Microbiology, Tumour and Cell Biology, describes the finding as conceptually simple. However, since RIFIN is found in many different variants, it has taken the research team a lot of time to isolate exactly which variant is responsible for this mechanism.