Malaria and pregnancy: Placental cytokine expression and its relationship to intrauterine growth retardation

Malaria infections during pregnancy can lead to the delivery of low- birth-weight infants. In this study, cytokine mRNA was measured in placentas from 23 malaria-infected and 21 uninfected primigravid women who had delivered in Mangochi, Malawi, a region with a high rate of transmission of falciparum malaria. Significantly increased expression of interleukin (IL)- 1β, IL-8, and tumor necrosis factor (TNF)-α and decreased expression of IL- 6 and transforming growth factor-β1 were found in malaria-infected compared with uninfected placentas. TNF-α and IL-8 were produced by maternally derived hemozoin-laden placental macrophages. Increased TNF-α expression was associated with increased placental hemozoin concentrations. Increased TNF-α or IL-8 expression in the placenta was associated with intrauterine growth retardation but not with preterm delivery. The results suggest that malaria infections induce a potentially harmful proinflammatory response in the placenta.