PLACENTAL PATHOLOGIC-CHANGES IN MALARIA - A HISTOLOGIC AND ULTRASTRUCTURAL-STUDY

  • 1 January 1982
    • journal article
    • research article
    • Vol. 109  (3) , 330-342
Abstract
Placental malarial changes (PMC) related to maternal plasmodium infection were present in 33% (247 cases) of a series of 741 placentas collected from an unselected population living in an area of high malarial endemicity (Haut-Ogooue, Gabon, Africa). Plasmodium were found on maternal thick blood films taken at the time of delivery in 42% of the women with and 24% of women without associated PMC. Plasmodium falciparum was the most frequent infecting organism. PMC were more frequent and, in general, more marked in primiparas. The primiparas were significantly (P < 0.001) more numerous in the group with PMC than in the control group without such changes. The mean weight of term placentas with malarial changes was significantly (46 g; P < 0.001) less than that of placentas without such changes. The morphologic changes were a combination of the following features: presence of parasites in the intervillous spaces; macrophage concentration in the intervillous spaces; malarial pigment deposits; excess of perivillous fibrinoid deposits; syncytiotrophoblastic damage; and trophoblastic basal lamina thickening. Plasmodium were found in placental intervillous spaces in 42% (105/247). Local parasitemia varied in magnitude; in a few cases, 30% or more of the maternal erythrocytes were infected. Macrophage concentration in the intervillous spaces was present in 29% (72/247) and was always associated with local parasitemia. Macrophages phagocytized red blood cells and malarial pigment, and their number varied inversely with that of the local parasites. Macrophages may play an important role in local parasite clearance. Malarial brown pigment was observed in all cases from the series. It had characteristic ultrastructural features and occurred in perivillous deposits of fibrinoid, in macrophages, or free in intervillous spaces. Excessive perivillous fibrinoid deposits were a constant histologic finding and were usually associated with syncytiotrophoblastic necrosis or ultrastructural damage such as partial microvilli loss, filamentous material accumulation in intracytoplasmic vacuoles, and podocyte-like cytoplasmic projections on the basal surface. At these sites the trophoblastic basal lamina was usually thickened. The peculiar placental changes in malaria, restricted to intervillous spaces and to villous surfaces, may be related to an immunopathologic process.

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