The most common blood type in Indians seems to provide better protection against the most deadly form of malaria. British scientists have found that people with blood group O – around 38% of the Indian population – are naturally protected from some of the most severe forms of the disease, which kills around two million people annually across the globe……....click & see
A team from Edinburgh University, with researchers in the US, Mali and Kenya, studied African children and found that those with this blood type were two-thirds less likely to experience coma or life-threatening anaemia conditions synonymous with severe malaria.
This discovery now brings hope of developing drugs which mimic the properties of red cells. In fatal malaria, it is often found that red blood cells infected by parasites block blood vessels which supply oxygen to the brain.
The malarial parasites arm the blood cells surface with proteins which stick to blood vessel walls. O and B are the commonest blood group among Indians. Nearly 32% of north Indians and 38% south Indians have O blood group.
“The finding that red cells present in O group blood play the major role in preventing malaria from worsening is a significant finding for India. Blood is made of antigens or proteins, some of which show protection against certain diseases. Why that occurs has not been scientifically proven yet but statistically, they have shown significant protection rates,” blood safety specialist Dr Debasish Gupta said.
Edinburgh University’s Dr Alex Rowe, whose finding was published in the journal ‘PNAS’ on Tuesday, said, “This explains why some people are less likely to suffer from life-threatening malaria than others and tells us that if we can develop a drug to reduce rosetting and mimic the effect of being blood group O, we may reduce the number of children dying from severe malaria.”
The scientists found that malaria parasites recruit healthy RBCs to stick to the parasite, encasing the infected RBC inside a so-called rosette. It makes the blockage, and the disease, worse.
However, the team’s findings suggest that group O RBCs do not easily join rosettes as the cells surface structure prevents it from sticking. The study suggests that reduced rosetting of malaria parasites is the reason why people with group O blood are less likely to suffer severe malaria.
“ABO blood group types were assessed on 567 blood samples from Malian children. We found that blood group O was present in only 21% of the severe malaria cases compared to 45% of other blood groups. Rosetting was shown to be significantly lower in parasite isolates from patients with blood group O compared to non-O blood groups,” the study said.
Source: The Times Of India