title: Peripheral blood cell signatures of Plasmodium falciparum infection during pregnancy.
abstract: Sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous spaces causes inflammation and pathology. Knowledge of the profiles of immune cells associated with the physiopathology of pregnancy-associated malaria (PAM) is scarce. We conducted a longitudinal, prospective study, both in Benin and Tanzania, including ∼1000 pregnant women in each site with systematic follow-up at scheduled antenatal visits until delivery. We used ex vivo flow cytometry to identify peripheral blood mononuclear cell (PBMC) profiles that are associated with PAM and anaemia, determining the phenotypic composition and activation status of PBMC in selected sub-groups with and without PAM both at inclusion and at delivery in a total of 302 women. Both at inclusion and at delivery PAM was associated with significantly increased frequencies both of B cells overall and of activated B cells. Infection-related profiles were otherwise quite distinct at the two different time-points. At inclusion, PAM was associated with anaemia, with an increased frequency of immature monocytes and with a decreased frequency of regulatory T cells (Treg). At delivery, infected women presented with significantly fewer plasmacytoid dendritic cells (DC), more myeloid DC expressing low levels of HLA-DR, and more effector T cells (Teff) compared to uninfected women. Independent associations with an increased risk of anaemia were found for altered antigen-presenting cell frequencies at inclusion, but for an increased frequency of Teff at delivery. Our findings emphasize the prominent role played by B cells during PAM whenever it arises during pregnancy, whilst also revealing signature changes in other circulating cell types that, we conclude, primarily reflect the relative duration of the infections. Thus, the acute, recently-acquired infections present at delivery were marked by changes in DC and Teff frequencies, contrasting with infections at inclusion, considered chronic in nature, that were characterized by an abundance of immature monocytes and a paucity of Treg in PBMC.
authors.affiliation: Centre d'étude et de recherche sur le paludisme associé à la grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin.
authors.forename: Samad
authors.initials: S
authors.lastname: Ibitokou
authors.forename: Mayke
authors.initials: M
authors.lastname: Oesterholt
authors.forename: Laurent
authors.initials: L
authors.lastname: Brutus
authors.forename: Sophie
authors.initials: S
authors.lastname: Borgella
authors.forename: Carine
authors.initials: C
authors.lastname: Agbowaï
authors.forename: Sèm
authors.initials: S
authors.lastname: Ezinmègnon
authors.forename: John
authors.initials: J
authors.lastname: Lusingu
authors.forename: Christentze
authors.initials: C
authors.lastname: Schmiegelow
authors.forename: Achille
authors.initials: A
authors.lastname: Massougbodji
authors.forename: Philippe
authors.initials: P
authors.lastname: Deloron
authors.forename: Marita
authors.initials: M
authors.lastname: Troye-Blomberg
authors.forename: Stefania
authors.initials: S
authors.lastname: Varani
authors.forename: Adrian J F
authors.initials: AJ
authors.lastname: Luty
authors.forename: Nadine
authors.initials: N
authors.lastname: Fievet
mesh_terms: D000328:Adult; D000740:Anemia / Q000097:blood / Q000150:complications / Q000276:immunology; D001402:B-Lymphocytes / Q000378:metabolism / Q000469:parasitology; D003713:Dendritic Cells / Q000166:cytology; D004912:Erythrocytes / Q000378:metabolism / Q000469:parasitology; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood / Q000150:complications / Q000235:genetics / Q000276:immunology; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D011247:Pregnancy; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000378:metabolism