title: Changes in systemic type 1 and type 2 immunity in normal pregnancy and pre-eclampsia may be mediated by natural killer cells.
abstract: A bias of T cell immunity towards type 2 (Th2) is thought to be critical for normal pregnancy. Pathological pregnancies, such as pre-eclampsia, are characterised by cell-mediated (Th1) immune dominance. The Th1/Th2 paradigm, however, is too simplistic. Normal pregnancy is associated with a systemic inflammatory response which increases throughout gestation. This inflammatory response is exaggerated in pre-eclampsia, a syndrome of the third trimester. T helper (Th) cells are considered the primary mediators of these altered immune responses, and other T cells, i.e. T cytotoxic (Tc) cells, and lymphocytes of the innate immune system, i.e. natural killer (NK) and NKT cells, have been largely disregarded. In this study, we have used novel pan type 1 (IL-18 receptor) and pan type 2 (ST2L) lymphocyte function markers in four-colour flow cytometry to broadly characterise peripheral blood lymphocyte populations from non-pregnant, normal pregnant and pre-eclamptic women. There were no changes in the Th1/Th2 or Tc1/Tc2 cell ratios between the three groups; however, the NK1/NK2 and NKT1/NKT2 cell ratios were significantly decreased in normal pregnancy compared with non-pregnant (p <0.001 and p <0.01, respectively) and pre-eclamptic women (p <0.05). These results confirm that immunoregulation occurs in pregnancy, but suggest a dominant role of the innate rather than the adaptive immune system.
authors.affiliation: Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Oxford, UK. angela.borzychowski@obs-gyn.ox.ac.uk
authors.forename: Angela M
authors.initials: AM
authors.lastname: Borzychowski
authors.forename: B Anne
authors.initials: BA
authors.lastname: Croy
authors.forename: W Ling
authors.initials: WL
authors.lastname: Chan
authors.forename: Christopher W G
authors.initials: CW
authors.lastname: Redman
authors.forename: Ian L
authors.initials: IL
authors.lastname: Sargent
mesh_terms: D000328:Adult; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D000072179:Interleukin-1 Receptor-Like 1 Protein; D020382:Interleukin-18 / Q000276:immunology / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology*; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D011225:Pre-Eclampsia / Q000276:immunology*; D011247:Pregnancy / Q000276:immunology*; D011956:Receptors, Cell Surface; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*
chemical_list: C079241:IL1RL1 protein, human; D000072179:Interleukin-1 Receptor-Like 1 Protein; D020382:Interleukin-18; D008565:Membrane Proteins; D011956:Receptors, Cell Surface