Aberrant uterine natural killer (NK)-cell expression and altered placental and serum levels of the NK-cell promoting cytokine interleukin-12 in pre-eclampsia.
OBJECTIVE
Natural killer (NK) cells are the most abundant lymphocyte population at the maternal-fetal interface. They are suggested to be important during placentation by controlling trophoblast invasion. If placentation is suboptimal, pre-eclampsia can occur.


METHODS
Decidual NK (dNK) cells were examined at delivery in 46 women, 22 pre-eclamptic women and 24 healthy controls, by staining for CD56 and CD94 with immunohistochemistry (IHC). Furthermore, we investigated the placental expression and the serum levels of the NK-cell activating cytokines interleukin(IL)-12, IL-15, IL-18 and the anti-inflammatory cytokine IL-10 by IHC and enzyme-linked immunosorbent assay (ELISA), respectively.


RESULTS
Pre-eclamptic women had higher number of CD56+ and CD94+ cells in the decidua, indicating an altered receptor expression of dNK cells. We also demonstrate for the first time that the villous trophoblasts show strong immunostaining for IL-12 in placentae from healthy controls, while women suffering from pre-eclampsia have significantly less IL-12. However, pre-eclamptic women had significantly elevated IL-12 and IL-15 levels in serum.


CONCLUSIONS
Results show increased numbers and altered phenotype of dNK cells in pre-eclampsia, supporting the importance of these cells for a healthy pregnancy. The altered receptor expression of dNK cells together with diminished placental IL-12 expression could implicate an altered NK cell-regulation in pre-eclampsia.
Bachmayer
Nora
N
Arrhenius Laboratories for Natural Sciences, Department of Immunology, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden. nora.bachmayer@imun.su.se
Rafik Hamad
Rangeen
R
Liszka
Lucie
L
Bremme
Katarina
K
Sverremark-Ekström
Eva
E
D048430:Cell Shape; D005260:Female; D006262:Health; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D018664:Interleukin-12 / Q000097:blood*; D019409:Interleukin-15 / Q000097:blood; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology*; D010641:Phenotype; D010920:Placenta / Q000378:metabolism* / Q000473:pathology; D011225:Pre-Eclampsia / Q000097:blood* / Q000473:pathology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood / Q000378:metabolism; D014327:Trophoblasts / Q000378:metabolism; D014599:Uterus / Q000276:immunology* / Q000473:pathology
D018836:Inflammation Mediators; D019409:Interleukin-15; D018664:Interleukin-12