IMMUNOGLOBULIN COMPLEX DEPOSITS IN PLASMODIUM-FALCIPARUM-INFECTED PLACENTAS FROM MALAWI AND PAPUA-NEW-GUINEA

Term placentas from 35 patients infected with Plasmodium falciparum we re obtained in Malawi in southeast Africa and six term placentas from patients infected with P. falciparum were obtained in Wewak, Papua New Guinea, Melanesia. The placental tissues were examined by light micro scopy and by an immunohistologic method to compare the pathologic chan ges of placentas in the two malaria-endemic countries. Using the numbe r of parasitized red blood cells (PRBC) in intervillous spaces, pregna nt women from Malawi with placental parasitemia were categorized into three groups. In the high PRBC group (> 20%, group I), there was no de position of IgE in fetal blood vessels. In contrast, IgE was observed in fetal blood vessels of the intermediate PRBC group (1-10%, group II ) and low PRBC group (< 1%, group III). In all six placentas from Papu a New Guinean women, deposition of immune complexes, including IgE, wa s observed in the fetal blood vessels. All placentas with deposition o f IgE in fetal blood vessels showed no sequestration of malaria parasi tes in intervillous spaces. Our data indicate that the amount of depos ition of IgE in the placenta from women infected with P. falciparum is inversely correlated with the degree of parasitemia at that site.