The role of soluble tumor necrosis factor receptor types I and II and tumor necrosis factor-alpha in malaria during pregnancy.

In a prospective study of rhesus monkeys inoculated with Plasmodium coatneyi or saline on an infection/gestational timeline, we determined the serum levels of tumor necrosis factor-alpha (TNF-alpha), soluble tumor necrosis factor receptor type I (sTNFR-I), and soluble tumor necrosis factor receptor type II (sTNFR-II) in peripheral blood throughout primigravid pregnancy, malaria infection, and a combination of the two. Our goal was to determine the association between levels of TNF-alpha and of its 2 soluble receptors and the course of pregnancy and/or malaria and infant outcome. We found that any detectable level of TNF-alpha was always associated with fetal death and that the sTNFRs may be important for fetal protection, possibly through neutralizing the toxic effects of TNF-alpha. Our findings also showed that increased levels of sTNFR-II were associated specifically with malaria and not with normal pregnancy or even pregnancy with low birth weight due to other causes. In contrast, increases in sTNFR-I levels during the later half of normal pregnancies indicate that sTNFR-I may be important in regulating TNF-alpha levels in preparation for normal labor and delivery.

Alterations in the profile of blood cell types during malaria in previously unexposed primigravid monkeys.

Malaria in nonimmune, primigravid women threatens both mother and fetus. We used the Plasmodium coatneyi/rhesus monkey model to examine factors associated with this. Clinical and immunologic responses during the blood stage of chronic malaria (4 months) were evaluated in 8 malaria-naive primigravid (PMI) and 8 age-matched nulligravid (NMI) infected monkeys, compared with those in 8 primigravid, noninfected control monkeys. Although parasitemia levels were similar, recrudescence was more frequent and prolonged, and anemia was more severe in PMI than in NMI monkeys. During infection, CD2+, CD4+, and CD8+ lymphocyte levels were higher in NMI than in PMI monkeys. Monocyte and neutrophil levels were lower in PMI than in NMI monkeys. During chronic, untreated malaria, NMI monkeys had a B lymphocyte count 23 times greater than that of PMI monkeys. Pregnancy-induced immunomodulation, defined as a lack of appropriate cellular responses to malaria, was indiscernible until the immune system was challenged by a pathogen.

Hematologic and lymphocyte immunophenotypic reference values for normal rhesus monkey (Macaca mulatta) umbilical cord blood; gravidity may play a role in study design.

Hematology and flow cytometry reference values for rhesus umbilical cord blood (UCB) were established in 17 healthy infant rhesus monkeys delivered by elective cesarean section 10 days preterm. The infants were born to age matched, singly caged primigravid or secundigravid dams. The hematology and flow cytometry values were determined by automated cell counter and by FACS. No significant differences were observed with respect to infant gender. With respect to gravida, the primigravid infants had a significantly higher percentage (P= 0.05) of CD20(+) B lymphocytes in UCB. These results provide useful reference values for future studies of maternal - fetal disease transmission, vaccine and drug evaluation in non-human primate pregnancy, as well as fetal programming and immune modulation, gene therapy and the use of UCB as a source of stem cells for research and transplantation. Importantly, our results suggest that maternal gravidity may be an important variable to consider.