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<jats:p>Clinical illness with<jats:named-content content-type="genus-species">Plasmodium falciparum</jats:named-content>or<jats:named-content content-type="genus-species">Plasmodium vivax</jats:named-content>compromises the function of dendritic cells (DC) and expands regulatory T (Treg) cells. Individuals with asymptomatic parasitemia have clinical immunity, restricting parasite expansion and preventing clinical disease. The role of DC and Treg cells during asymptomatic<jats:named-content content-type="genus-species">Plasmodium</jats:named-content>infection is unclear. During a cross-sectional household survey in Papua, Indonesia, we examined the number and activation of blood plasmacytoid DC (pDC), CD141<jats:sup>+</jats:sup>, and CD1c<jats:sup>+</jats:sup>myeloid DC (mDC) subsets and Treg cells using flow cytometry in 168 afebrile children (of whom 15 had<jats:named-content content-type="genus-species">P. falciparum</jats:named-content>and 36 had<jats:named-content content-type="genus-species">P. vivax</jats:named-content>infections) and 162 afebrile adults (of whom 20 had<jats:named-content content-type="genus-species">P. falciparum</jats:named-content>and 20 had<jats:named-content content-type="genus-species">P. vivax</jats:named-content>infections), alongside samples from 16 patients hospitalized with uncomplicated malaria. Unlike DC from malaria patients, DC from children and adults with asymptomatic, microscopy-positive<jats:named-content content-type="genus-species">P. vivax</jats:named-content>or<jats:named-content content-type="genus-species">P. falciparum</jats:named-content>infection increased or retained HLA-DR expression. Treg cells in asymptomatic adults and children exhibited reduced activation, suggesting increased immune responsiveness. The pDC and mDC subsets varied according to clinical immunity (asymptomatic or symptomatic<jats:named-content content-type="genus-species">Plasmodium</jats:named-content>infection) and, in asymptomatic infection, according to host age and parasite species. In conclusion, active control of asymptomatic infection was associated with and likely contingent upon functional DC and reduced Treg cell activation.</jats:p>

Original publication

DOI

10.1128/iai.00226-15

Type

Journal

Infection and Immunity

Publisher

American Society for Microbiology

Publication Date

08/2015

Volume

83

Pages

3224 - 3232