Reciprocal regulation of Th1- and Th2-cytokine-producing T cells during clearance of parasitemia in Plasmodium falciparum malaria.

Flow cytometry for the intracellular detection of T-cell cytokines was performed for 15 Gabonese patients during acute uncomplicated Plasmodium falciparum malaria. A striking expansion of CD4(+) and CD8(+) T cells producing gamma interferon (IFN-gamma) was found during drug-induced clearance of parasitemia, paralleled by a decrease of interleukin-2 (IL-2) production. The frequency of IL-4- and IL-13-producing CD4(+) cells gradually decreased, whereas the frequency of T cells producing IL-2(+)-IFN-gamma+, IL-4(-)-IL-5(+), and IL-4(+)-IL-5(+) cytokines as well as IL-4(+)-IFN-gamma+ and IL-13(+)-IFN-gamma+ cytokines was not significantly altered. The capacity for IL-10 production within the CD4(+) subset increased due to an expansion of both IL-10(+)-IFN-gamma- and IL-10(+)-IFN-gamma+ cytokine-expressing cells. Thus, a more pronounced Th2-driven immune response during acute untreated P. falciparum infection with a shift towards Th1 responsiveness induced by parasite clearance is suggested.