title: Is parturition-timing machinery related to the number of inhibitor CD94/NKG2A positive uterine natural killer cells?
abstract: Prematurity is the most common cause of infant mortality and morbidity. To prevent this, the timing of parturition and its mechanisms should be understood. It is likely that inhibitor CD94/NKG2A positive decidual natural killer cells (uNK) provide for the continuation of pregnancy. Here, we aimed to evaluate whether CD94/NKG2A positive uNK cells are highest in elective cesarian section (C/S) (suggesting ongoing gestation), moderate in normal full-term birth, and lowest in pre-eclamptic parturition.
  
  
  
  Of 48 pregnant women, 21 C/S, 16 normal, and 11 pre-eclamptic deliveries were included in this study. Five placentas in each group were assigned randomly. After staining, the volumetric analysis of the placental villi and villous blood vessels was performed via the Cavalieri principle. The CD94/NKG2A positive uNK cells were counted using the physical disector method.
  
  
  
  The gestation periods and birth weights of the pre-eclamptic deliveries were lower than those of the other two groups. Additionally, the villi and villous vascular volumes were lowest in the pre-eclamptic placentas. As proposed in our hypothesis, the inhibitor CD94/NKG2A positive uNK cells were the highest in the C/S, moderate in the normal, and lowest in the pre-eclamptic placentas.
  
  
  
  These data suggest that CD94/NKG2A positive uNK cells are related with the continuation of pregnancy, and that our human model could be used to search for parturition-timing machinery. We believe that CD94/NKG2A positive uNK cells are also related to the timing of birth.
authors.affiliation: Department of Pediatrics, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Mazi
authors.affiliation: Department of Histology-Embryology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: Z
authors.initials: Z
authors.lastname: Altunkaynak
authors.affiliation: Department of Histology-Embryology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Aydin
authors.affiliation: Department of Obstetrics-Gynecology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Kocak
authors.affiliation: Department of Obstetrics-Gynecology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: D
authors.initials: D
authors.lastname: Guven
authors.affiliation: Department of Histology-Embryology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: A P
authors.initials: AP
authors.lastname: Turkmen
authors.affiliation: Department of Pediatric Immunology-Allergy, School of Medicine, Ondokuz Mayis University, Samsun, Turkey. yildiran@omu.edu.tr.
authors.forename: A
authors.initials: A
authors.lastname: Yildiran
mesh_terms: D000328:Adult; D003656:Decidua / Q000166:cytology; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology*; D055654:NK Cell Lectin-Like Receptor Subfamily C / Q000378:metabolism*; D051920:NK Cell Lectin-Like Receptor Subfamily D / Q000378:metabolism*; D011247:Pregnancy; D011971:Receptors, Immunologic / Q000378:metabolism; D055815:Young Adult
chemical_list: C497869:KLRD1 protein, human; D055654:NK Cell Lectin-Like Receptor Subfamily C; D051920:NK Cell Lectin-Like Receptor Subfamily D; D011971:Receptors, Immunologic
keywords: CD94/NKG2A; Continuation of pregnancy; Parturition-timing machinery; Preeclampsy; uNK cells