OA-58 Associations between prenatal malaria exposure, maternal antibodies at birth and malaria susceptibility during the first year of life in Burkina Faso

Résumé fourni par la source

Background Although infants are thought to be protected against malaria during the first months of life mainly due to maternal antibodies, malaria in early childhood is not uncommon in high-transmission settings and susceptibility to Plasmodium falciparum infections varies between infants. This study aimed to investigate how different categories of prenatal malaria exposure (PME) influence levels of maternal antibodies in cord blood samples and examined the effect of maternal antibody concentrations at birth on subsequent risk of malaria in early childhood. Methods A birth cohort study (N=661) was nested within the COSMIC clinical trial (NCT01941264) in Burkina Faso. P. falciparum infections during pregnancy and infants’ clinical malaria episodes detected during the first year of life were recorded. The levels of maternal IgG and IgG1-4 to 15 P. falciparum antigens were measured in cord blood by quantitative suspension array technology. Results Results showed a significant variation in the magnitude of maternal antibody levels in cord blood, depending on the PME category, with past placental malaria (PM) more frequently associated with significant increases of IgG and/or subclass levels across three groups of antigens defined as pre-erythrocytic, erythrocytic and markers of PM, as compared to those from the cord of non-exposed control mothers. High levels of antibodies to certain erythrocytic antigens (EBA140, EBA175, MSP142, and MSP5) were independent predictors of protection from clinical malaria while antibodies to VAR2CSA-DBL1-2 and DBL3-4 were significantly associated with an increased malaria risk during the first year of life. Remarkably, ratios of protective-to-risk antibodies above 1 at individual level were associated with protection from clinical malaria during the first year of life. Conclusion These findings indicate that PME categories have different effects on the levels of maternal-derived antibodies to malaria antigens in children at birth and that, this might drive heterogeneity to clinical malaria susceptibility in early childhood.

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