Determination of the effect of human immunodificiency virus-1 and placental malaria infection on maternal anti-malarial anti-body level and transfer in pregnant women
Mulonzia, Naomi Wangui
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Pregnant women are more susceptible to malaria infection than their non-pregnant counterparts. One of the hallmark of plasmodium falciparum infection in pregnant women is the sequestration of malaria parasites in the placental intervillous space a phenomenon referred to as placental malaria. Placental malaria contributes to low birth weight infants and this is a single greatest risk factor for early infant borbidity and mortality. In tropical countries, in addition to malaria infection, Human immunodeficiecy virus HIV-1 has become another major public health issue. Although earlier studies did not find a significant interaction between malaria and HIV infections, recent epidemiologicla investigations suggest that there is a strong biological interaction between HIV -1 and P . falciparum malaria infections during pregnancy. Some of the adverse outcomes caused by this co infection include; increased incidence of maternal malaria, increased incidence of congenital malaria and increased neotatal mortality of infants born to mothers with placenta malaria and HIV-1 co-infection. However, the immunological basis for the susceptibility of pregnant women to placental malaria and the adverse effect of malaria and HIV are not well understood. In addition immunoglobulin G (IgG) is known to be transplancentally transferred to the foetus during pregnancy and this is thought to provide protection to infants in the first few months of life. In the light of the crucial role of maternally transferred immunoglobulins and the recently identified biological link between placenta malaria and HIV-1 infection in pregnancy, the effect of HIV-1 and placental malaria infections on maternal antibody levels and transfer was investigated. This study was carried out to determine if there is any alteration in the humoral immune responses of pregnant women with P falciparum infection. Specifically this study was designed to determine the effect on anti-malarial antibody levels ii) if there are any differences in the maternal antibody levels in the presence or absence of placental malaria infection, iii) if placental malaria affects passive transfer of antibodies from mother to child and iv) if HIV-1 infection impairs the antibody levels to malaria in pregnant women. Paired maternal and cord plasma were used to determine the malaria-specific antibody levels in four groups of women namely, HIV and placental malaria positive, HIV and placental malaria negative, HIV negative and placental malaria positive, and HIV positive and placental malaria negative. The antibody levels were determined using standard enzyme-linked immunosorbent assay (ELISA). Peptides corresponding repeat regions of the circumsporozoite-protein (CSP) and liver stage antigen (LSA-1) were used as target antigens. The results showed that primigravidae had similar antibody levels to multigravidae. Mothers with placental malaria had higher concentration of total immunoglobulins (Ig), IgG, IgG1 and IgG3 subclasses of anti-malarial antibodies than mothers with no placental malaria. In contrast to recent reports, placental malaria did not appear to reduce the levels of malaria specific IgG. However, IgG1 antibodies seemed to be more efficiently transferred than IgG3 antibodies. Mothers with HIV-1 infection had similar levels of antibodies when compared to those with no HIV-1 infection implying that HIV-1 did not impair malaria specific antibody levels. In mothers with both HIV-1 and placental malaria infections, although total Ig and IgG levels were not altered, IgG1 levels were particularly lower when compared to the HIV-1 (-)/placental malaria (+) group. Hence the observed increased incidence of malaria infection in pregnant women with HIV-1 infection may not be related to anti-malarial antibody levels.
- MST-Zoological Sciences