Malaria in pregnancy predisposes to maternal
anemia and low birth weight (LBW). We examined the possible roles of the
cytokines tumor necrosis factor alpha (
TNF-alpha) and
gamma interferon (IFN-gamma) in these adverse outcomes. We measured
cytokine concentrations in placental, peripheral, and cord blood plasma in relation to
malaria parasitemia and placental monocyte accumulation in 276 Malawian women. Maternal
hemoglobin concentration, human immunodeficiency virus status, and infant
birth weight were determined. Concentrations of
TNF-alpha in placental blood were correlated with densities of Plasmodium falciparum-infected erythrocytes (P < 0.0001) and of intervillous monocyte infiltrates (P < 0.0001) on placental histology. Peripheral blood
TNF-alpha concentrations were relatively low and were weakly associated with
malaria.
TNF-alpha concentrations were higher in placental blood, where they were strongly associated with
malaria. Placental plasma
TNF-alpha levels were higher in women who had LBW babies (P = 0.0027), women with febrile symptoms (P < 0.0001), and teenage mothers (P = 0.04) than in other women. The presence of
TNF-alpha in cord blood was not associated with
malaria infection. IFN-gamma levels were infrequently elevated, and elevated IFN-gamma levels were not associated with poor pregnancy outcomes. Placental production of
TNF-alpha, but not of IFN-gamma, may be implicated in impaired fetal growth in Malawian women.