Plasmodium falciparum malaria and human red cells. II. Red cell genetic traits and resistance against malaria.

In 702 Nigerian children under 6 years of age the incidence and the severity of malarial infection was studied with respect to haemoglobin types and red cell glucose-6-phosphate dehydrogenase variants. The results suggest that Hb AS as well as the female genotype GdA-/GdB offer selective advantage against the disease. Parasite densities in carriers of these genotypes were significantly lower than in other subjects. Whereas protection by Hb AS was found mainly in children between 2 and 4 years of age, the advantage afforded by GdA-/GdB was similar in all age groups. Possible mechanisms are discussed.