The γ/δ T-cell response to plasmodium falciparum malaria in a population in which malaria is endemic.

Abstract

Frequencies and absolute numbers of peripheral g/d T cells have been reported to increase after episodes of Plasmodium falciparum malaria in adults with limited or no previous malaria exposure. In contrast, little is known about the g/d T-cell response to malaria in children from areas where malaria is endemic, who bear the burden of malaria-related morbidity and mortality. We investigated the g/d T-cell response in 19 Ghanaian children from an area of hyperendemic, seasonal malaria transmission. The children presented with cerebral malaria (n 5 7), severe malarial anemia (n 5 5), or uncomplicated malaria (n 5 7) and were monitored from admission until 4 weeks later. We found no evidence of increased frequencies of g/d T cells in any of the patient groups, whereas one adult expatriate studied in Ghana and three adults admitted to the hospital in Copenhagen, Denmark, all with uncomplicated, primary P. falciparum malaria, showed increased g/d T-cell frequencies similar to those previously reported. All patients had lowered absolute numbers of peripheral g/d T cells at admission, changing to increased numbers by days 7 to 14 and then returning to normal levels. The study raises questions regarding age and degree of previous exposure as determinants of malaria-induced g/d T-cell responses.