Parasitic Infections in Pregnancy Decreases Perinatal Transfer of Pneumococcal Antibodies

Background: Transplacental antibody transfer is an active, dynamic process that provides important protection to the na•ve infant during the early months of the life, guarding against exposure to many pathogens. Awareness of this passive protection has helped to guide prenatal screening and immunization strategies, although there are several factors that can alter its efficiency. In recent years, the effect of perinatal parasitic infections and their immunomodulatory effects on the host have begun to be elucidated. This study was designed to investigate whether maternal parasitic infection can alter the process of transplacental antibody transfer to infants.

Methods: 580 pregnant Kenyan mothers were enrolled in the parent study and tested at prenatal visits for malaria, soil transmitted helminths, G. lamblia, S. stercoralis and S. haematobium infection. For this analysis, five stratified groups were selected, including uninfected women (N=30), women with single parasite infections (malaria, N=30; hookworm, N=30; schistosomiasis, N=10). To control for the known effects of antibody transfer related to gestational age, only mothers with infants scoring 37 weeks or higher on the Dubowitz score of gestational age were included. Maternal plasma at delivery and infant cord blood were tested via a multiplex fluorescent bead assay for antigen-specific IgG concentrations against 10 pneumococcal polysaccharide serotypes (PnPs 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F and 23F), diphtheria toxoid, and Haemophilus influenzae type B.

Results: Comparing the ratio of geometric mean antibody concentrations between infant cord blood and maternal blood, there was a significant reduction in the level of antibodies against pneumococcal serotypes 1, 4, 5, 6B, 7F, 9V, and 18c, by ANOVA (p<0.02) transferred from women with malaria, hookworm, or S. haematobium infections. For diphtheria toxoid and H. influenzae type B antigens, there were no significant changes between groups.

Conclusion: Perinatal parasitic infections alter the passive transfer of maternalIgGantibodies to developing infants in a manner that is specific to the type of parasitic infection and the category of target antigen.