The impact of lipid-based nutrient supplementation on anti-malarial antibodies in pregnant women in a randomized controlled trial

Abstract

BackgroundMalaria and undernutrition frequently coexist, especially in pregnant women and young children. Nutrient supplementation of these vulnerable groups might reduce their susceptibility to malaria by improving immunity.MethodsAntibody immunity to antigens expressed by a placental-binding parasite isolate, a non-placental binding parasite isolate, merozoites and schizonts at enrolment (before 20 gestation weeks) and at 36 gestation weeks were measured in 1,009 Malawian pregnant women receiving a daily lipid-based nutrient supplement, multiple micronutrients or iron and folic acid, who were participants in a randomized clinical trial assessing the effects of nutrient supplementation on pregnancy outcomes and child development(registration ID: NCT01239693).ResultsAntibodies to placental-binding isolates significantly increased while antibodies to most merozoite antigens declined over pregnancy. Overall, after adjustment for covariates, the type of supplementation did not influence antibody levels at 36 gestation weeks or the rate of change in antibody levels from enrolment to 36 weeks. A negative association between maternal body mass index and opsonizing antibodies to placental-binding antigens (coefficient (95% CI) -1.04 (−1.84, −0.24), was observed. Similarly, women with higher socioeconomic status had significantly lower IgG and opsonizing antibodies to placental-binding antigens. Neither of these associations was significantly influenced by the supplementation type.ConclusionsIn the current cohort nutrient supplementation did not affect anti-malarial antibody responses, but poor and undernourished mothers should be a priority group in future trials.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0707-2) contains supplementary material, which is available to authorized users.

Association between malaria immunity and pregnancy outcomes among Malawian pregnant women receiving nutrient supplementation

“…All participants received 2 doses of sulfadoxine-pyrimethamine (SP, Fansidar ® ). The trial design, details of the nutrient supplements, and main findings have been published elsewhere [25, 26]; the type of nutrient supplementation did not affect maternal anti-malarial antibodies, or susceptibility to malaria. Maternal haemoglobin at 36 gestation weeks (gw) and birth weight, gestational age and infant length at delivery were measured, and placental histology was examined.…”

“…Flow cytometry based immunoassays were performed as previously described [25] to determine relative levels of naturally-acquired IgG to VSA expressed by the parasite isolates described above, and to measure levels of antibodies that opsonize pRBC for phagocytosis by THP-1 cells. Plasma was assayed at 1:20 dilution (IgG to VSA) or 1:10 (opsonizing antibodies).…”

“…Recombinant merozoite antigens MSP1 19kD, MSP2, MSP3, PfRh2 (construct PfRh2-2030) (6088–7584 bp) and EBA175 (region III-V) were prepared as detailed [25]. A fluorescent immunosorbent assay was designed to measure IgG to merozoite antigens as described in [25] and the IgG levels were reported as a percentage of the positive control, where the positive control was a pool of human plasma collected from individuals with immunity to malaria.…”

“…A fluorescent immunosorbent assay was designed to measure IgG to merozoite antigens as described in [25] and the IgG levels were reported as a percentage of the positive control, where the positive control was a pool of human plasma collected from individuals with immunity to malaria.…”

“…The selected covariates included gravidity, maternal age, HIV, bed net use, body mass index (BMI) at enrolment, malaria microscopy at enrolment, socioeconomic status (SES), study site, season at enrolment and supplementation group, and were recorded as described [25]. These covariates were chosen based on their effects on malaria antibody levels and pregnancy outcomes in the cohort, or their previously-demonstrated biological relevance to the association between antibody levels and pregnancy outcomes.…”