THE GAMMA DELTA-T-CELL RESPONSE TO PLASMODIUM-FALCIPARUM MALARIA IN APOPULATION IN WHICH MALARIA IS ENDEMIC/

Frequencies and absolute numbers of peripheral gamma/delta T cells hav e been reported to increase after episodes of Plasmodium falciparum ma laria in adults with limited or no previous malaria exposure. In contr ast, little is known about the gamma/delta T-cell response to malaria in children from areas where malaria is endemic, who bear the burden o f malaria-related morbidity and mortality. We investigated the gamma/d elta T-cell response in 19 Ghanaian children from an area of hyperende mic, seasonal malaria transmission. The children presented with cerebr al malaria (n = 7), severe malarial anemia (n = 5), or uncomplicated m alaria (n = 7) and a ere monitored from admission until 4 weeks later, We found no evidence of increased frequencies of gamma/delta 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 increa sed gamma/delta T-cell frequencies similar to those previously reporte d, All patients had lowered absolute numbers of peripheral gamma/delta T cells at admission, changing to increased numbers by days 7 to 14 a nd then returning to normal levels, The study raises questions regardi ng age and degree of previous exposure as determinants of malaria-indu ced gamma/delta T-cell responses.