Immunoglobulins against the surface of Plasmodium falciparum-infected erythrocytes increase one month after delivery

BACKGROUND: The risk of Plasmodium falciparum malaria increases during pregnancy and at early postpartum. Immunological and physiological alterations associated with pregnancy that persist after delivery may contribute to the susceptibility to P. falciparum during early postpartum period. METHODS: To determine changes in antibody-mediated responses after pregnancy, levels of Immunoglobulin G (IgGs) specific for P. falciparum were compared in 200 pairs of plasmas collected from Mozambican women at delivery and during the first two months postpartum. IgGs against the surface of erythrocytes infected with a P. falciparum chondroitin sulphate A binding line (CS2) and a paediatric isolate (MOZ2) were measured by flow cytometry. RESULTS: IgG levels against CS2 and MOZ2 were higher at postpartum than at delivery (p = 0.033 and p = 0.045, respectively) in women without P. falciparum infection. The analysis stratified by parity and period after delivery showed that this increase was significant in multi-gravid women (p = 0.023 for CS2 and p = 0.054 for MOZ2) and during the second month after delivery (p = 0.018 for CS2 and p = 0.015 for MOZ2). CONCLUSIONS: These results support the view that early postpartum is a period of recovery from physiological or immunological changes associated with pregnancy.