Erythrocyte variants and the nature of their malaria protective effect

The malaria threat to global health is exacerbated by widespread drug resistance in the Plasmodium parasite and its insect vector, and the lack of an efficacious vaccine. Infection with Plasmodium parasites can cause a wide spectrum of pathologies, from a transient mild form of anaemia to a severe and rapidly fatal cerebral disease. Epidemiological studies in humans and experiments in animal models have shown that genetic factors play a key role in the onset, progression, type of disease developed and ultimate outcome of malaria. The protective effect of polymorphic variants in erythrocyte-specific structural proteins or metabolic enzymes against the blood-stage of the disease is one of the clearest illustrations of this genetic modulation, and has suggested coevolution of the Plasmodium parasite with its human host in areas of endemic disease. Here, we present a brief overview of erythrocyte polymorphisms with biological relevance to malaria pathogenesis, and current work on the mechanism(s) by which these mediate their protective effect. The recent addition of erythrocyte pyruvate kinase to this group of protective genes will also be discussed.