Cytokine production by non-stimulated peripheral blood NK cells and lymphocytes in early-onset severe pre-eclampsia without HELLP.

Preeclampsia involves an exacerbated maternal inflammatory response that suggests a possible role of innate immunity. NK cells can promote this kind of response through cytokine production and the expression of activating or inhibitory receptors. The aims of the present study were to explore cytokine production by peripheral blood mononuclear cells, as well as cytotoxic ability and receptor expression for HLA-E and HLA-G molecules in peripheral natural killer (NK) cells of women with early-onset severe preeclampsia without HELLP (hemolysis, elevated liver enzyme levels and a low platelet count) syndrome. The expression of the ILT2, KIRDL4, NKG2A, and NKG2C receptors and of cytotoxic activity was measured in non-stimulated NK cells, whereas the intracellular expression of IL-4, IL-10, IL-13, IL-12, IFNγ, TNF and VEGF, was assessed in non-stimulated peripheral blood mononuclear cells subsets using flow cytometry. Circulating soluble HLA-G was also determined by ELISA. The intracellular cytokines tested were significantly higher in NK cell subsets from severely preeclamptic women compared with the control group. On the other hand, the percentage of NK cells expressing NKG2A or NKG2C and the cytotoxic activity of NK cells were significantly higher in severely preeclamptic women. Furthermore, there was a significant correlation between urine protein concentration and soluble human leukocyte antigen G (soluble HLA-G) in serum. We conclude that patients with early-onset severe preeclampsia without HELLP syndrome have increased NK cell function related to cytokine production, cytotoxicity and expression of lectin-like receptors such as NKG2.

The proportion of symmetric and asymmetric IgG antibody molecules synthesized by a cellular clone (hybridoma) can be regulated by placental culture supernatants.

The purpose of the present work was to establish whether the placenta is producing factors favoring an increased synthesis of asymmetric IgG antibodies which are known to assume a protective effect upon paternal antigens to which they largely are specific. In this way they can contribute to fetal survival in the maternal uterine environment. The hybridoma cell lines OKT8 (anti-CD8) and 112B4 (anti-DNP) were used in this respect since they synthesized both symmetric and asymmetric molecules of the IgG2a and IgG1 subclasses, respectively, murine isotypes in which anti-paternal antibodies have been detected. The cells were cultured in RPMI 1640 medium supplemented with 10% BCS and different amounts (5, 10, and 20%) of human placental supernatant. After incubation for 3 days at 37 degrees C in a humid chamber containing 5% CO2 the cells were centrifuged and the antibodies were obtained from the culture medium by a purification procedure involving precipitation at 50% ammonium sulfate saturation followed by DEAE-cellulose chromatography. Symmetric and asymmetric antibodies were separated by Con A-Sepharose affinity chromatography, the latter lectin retaining selectively only asymmetric IgG molecules. Both OKT8 and 112B4 hybridomas presenting a stable background synthesis of 15-17% of asymmetric antibodies have shown an increased level reaching 27-28% of these molecules in the presence of 5-10% placental supernatant added to the RPMI 1640 culture medium. These results clearly show that placental factors can up-regulate efficiently the synthesis of asymmetric IgG molecules of different isotypes secreted by plasma cells.