No abstract

Flow cytometry for the intracellular detection of T-cell cytokines was performed for 15 Gabonese patients during acute uncomplicatedPlasmodium falciparum malaria. A striking expansion of CD4+ and CD8+ T cells producing gamma interferon (IFN-γ) 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-γ+, IL-4−–IL-5+, and IL-4+–IL-5+ cytokines as well as IL-4+–IFN-γ+ and IL-13+–IFN-γ+ 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-γ− and IL-10+–IFN-γ+ 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.

No abstract

The frequency of cytokine-producing T cells was assessed in patients of different age groups (29 infants, aged 1-5 years; 30 schoolchildren, aged 6-14 years; 26 adults, aged >15 years) with acute Plasmodium falciparum malaria from Gabon. By using flow cytometry for the intracellular detection of cytokines, a striking expansion was seen, in adults compared with children, of CD4+ and CD8+ T cells with the following profiles of type 1 cytokine production: interleukin (IL)-2-/interferon (IFN)-gamma+, IL-2+/IFN-gamma+, and IL-2+/IFN-gamma-. Patients with hyperparasitemia had a significantly lower frequency of IL-2-/IFN-gamma+ CD4+ cells. Type 2 cytokine expression (IL-4+/IFN-gamma-, IL-13+/IFN-gamma-) and type 0 cytokine expression (IL-4+/IFN-gamma+, IL-13+/IFN-gamma+) were also increased in adults within the CD4+ subset. Frequencies of IL-5+/IL-4+, IL-10+/IFN-gamma-, and IL-10+/IFN-gamma+ cells were similar in all groups. The increased frequency of both type 1 and type 2 cytokine-producing T cells in adults is likely to be of significance in the protection against P. falciparum malaria.