Changes in monocyte subsets are associated with clinical outcomes in severe malarial anaemia and cerebral malaria

Jade Royo (1) , Mouna Rahabi (1) , Claire Kamaliddin (2) , Sem Ezinmegnon (3) , David Olagnier (4) , Hélène Authier (1) , Achille Massougbodji (3) , Jules Alao (5) , Yélé Ladipo (5) , Philippe Deloron (2) , Gwladys Bertin (2) , Bernard Pipy (1) , Agnès Coste (1) , Agnès Aubouy (1)

1 PHARMA-DEV - Pharmacochimie et Biologie pour le Développement
2 MERIT - UMR_D 216 - Mère et enfant en milieu tropical : pathogènes, système de santé et transition épidémiologique
3 CERPAGE - Centre d’Etude et de Recherche sur le Paludisme Associé à la Grossesse et l’Enfance [Cotonou, Bénin]
4 Aarhus University [Aarhus]
5 CHU-MEL - Centre Hospitalier Universitaire de la Mère et de l'Enfant Lagune

Monocytes are plastic heterogeneous immune cells involved in host-parasite interactions critical for malaria pathogenesis. Human monocytes have been subdivided into three populations based on surface expression of CD14 and CD16. We hypothesised that proportions and phenotypes of circulating monocyte subsets can be markers of severity or fatality in children with malaria. To address this question, we compared monocytes sampled in children with uncomplicated malaria, severe malarial anaemia, or cerebral malaria. Flow cytometry was used to distinguish and phenotype monocyte subsets through CD14, CD16, CD36 and TLR2 expression. Data were first analysed by univariate analysis to evaluate their link to severity and death. Second, multinomial logistic regression was used to measure the specific effect of monocyte proportions and phenotypes on severity and death, after adjustments for other variables unrelated to monocytes. Multivariate analysis demonstrated that decreased percentages of non-classical monocytes were associated with death, suggesting that this monocyte subset has a role in resolving malaria. Using univariate analysis, we also showed that the role of non-classical monocytes involves a mostly anti-inflammatory profile and the expression of CD16. Further studies are needed to decipher the functions of this sub-population during severe malaria episodes, and understand the underlying mechanisms.

Mots clés: Biomarkers; Immunology

Domaines: Sciences du Vivant [q-bio]

Jade Royo, Mouna Rahabi, Claire Kamaliddin, Sem Ezinmegnon, David Olagnier, et al.. Changes in monocyte subsets are associated with clinical outcomes in severe malarial anaemia and cerebral malaria. Scientific Reports, 2019, 9, pp.17545. ⟨10.1038/s41598-019-52579-7⟩. ⟨hal-03355622⟩