Frequency of cytokine-producing T cells in patients of different age groups with Plasmodium falciparum malaria

The frequency of cytokine-producing T cells was assessed in patients of dif ferent 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 cyt okines, a striking expansion was seen, in adults compared with children, of CD4(+) and CD8(+) T cells with the following profiles of type 1 cytokine p roduction: interleukin (IL)-2(-)/interferon (IFN)-gamma(+), IL-2(+)/IFN-gam ma(+), and IL-2(+)/IFN-gamma(-). Patients with hyperparasitemia had a signi ficantly lower frequency of IL-2(-)/IFN-gamma(+) CD4(+) cells. Type 2 cytok ine expression (IL-4(+)/IFN-gamma(-), IL-13(+)/IFN-gamma(-)) and type 0 cyt okine expression (IL-4(+)/IFN-gamma(+), IL-13(+)/IFN-gamma(+)) were also in creased in adults within the CD4+ subset. Frequencies of IL-5(+)/IL-4(+), I L-10(+)/IFN-gamma(-), and IL-10(+)/IFN-gamma(+) cells were similar in all g roups. 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 agains t P. falciparum malaria.