Collaborative research led by scientists from the University of Edinburgh has sparked hope for a new avenue in the treatment of Africa’s biggest killer: malaria.
New research, published in the journal Proceedings of the National Academy of Sciences, has shown that people with blood group O are naturally protected from the most severe forms of the disease, which claimed around two million lives last year – the vast majority in sub-Saharan Africa.
The Edinburgh-based team, headed by Dr Alex Rowe of the university’s School of Biological Sciences, have shown there to be significant links between blood type and individual susceptibility to fatal malaria. Studies of African children in disease endemic regions concluded that those with O type blood were 66 per cent less likely to suffer from unrousable coma and life threatening anaemia – symptoms characteristic of fatal malaria.
Malaria infection is caused by the microscopic parasite Plasmodium falciparum, which targets red blood cells. An often fatal consequence of infection is the clumping of healthy cells around the infected ones. These clumps of cells, known as rosettes, have the potential to block blood vessels supplying the brain, starving it of oxygen.
The crux of this latest research is the finding that cells of the blood type O lack particular structures found in AB, A and B blood groups. These structures are involved in rosette formation, as they aid attachment of the infected cell to the wall of the blood vessel, as well as encouraging recruitment of healthy cells. As a result, type O blood cells form rosettes less readily than cells from other blood groups, and the rosettes that do form are weaker and more prone to disruption.
This is not the first time blood characteristics have been shown to affect susceptibility to malaria. Sufferers of mild forms of sickle cell anaemia - a disease prominent in Africa - have been found to be immune to malaria as a result of the abnormal shape of their red blood cells.
Dr Rowe said: “If we can develop a drug or a vaccine to reduce rosetting and mimic the effect of being blood group O, we may be able to reduce the number of children dying from severe malaria in sub-Saharan Africa.”