title: Decidual CD56+ Natural Killer Cells in Spontaneous Early Pregnancy Loss- An Immunohistochemical Study.
abstract: BACKGROUND
  Natural killer cells are believed to promote placental and trophoblastic growth and provide immune- modulation at maternal-fetal interface in pregnancy and their role in reproductive failure has been a matter of discussion.
  
  
  OBJECTIVE
  To study CD56+ Natural killer cells in spontaneous pregnancy loss.
  
  
  METHODS
  In this prospective observational study, formalin-fixed paraffin embedded sections from products of conception from twenty women each with spontaneous early pregnancy loss (test group) and elective pregnancy termination (control group). Immunohistochemical staining with CD 56 monoclonal antibody was done by avidin-biotin peroxidase technique. CD56+ cells in decidua were counted under light microscopy by two independent observers in ten high power fields (40X) and mean cell count taken. Student's paired 't'-test was used to statistically compare CD56+ NK cell population between the test and control groups.
  
  
  RESULTS
  The mean number of CD56+ NK cells was higher in the decidual tissue of women who had spontaneous early pregnancy loss (mean±SD, 57.55±1.79) as compared to the mean number of CD56+ NK cells in the decidual tissue from women who underwent elective termination (mean±SD, 50.9±3.46). The difference was statistically significant (difference of 6.65 with 95% confidence interval of 4.76 to 8.54, p-value <0.0001).
  
  
  CONCLUSIONS
  This could imply that CD56+ NK cells have a role in the pathogenesis of spontaneous early pregnancy loss and further large scale studies can throw more light on the mechanism and designing of appropriate therapy.
authors.affiliation: Professor, Department of Pathology, Chettinad Hospital and Research Institute , Kancheepuram, Tamil Nadu, India .
authors.forename: Balamurugan
authors.initials: B
authors.lastname: Senthilnayagam
authors.affiliation: Intern, Department of Pathology, Chettinad Hospital and Research Institute , Kancheepuram, Tamil Nadu, India .
authors.forename: Sridhar
authors.initials: S
authors.lastname: Karthikeyan
authors.affiliation: Assistant Professor (Formerly), Department of Microbiology, Chettinad Hospital and Research Institute , Kancheepuram, Tami Nadu, India .
authors.forename: Jayapriya
authors.initials: J
authors.lastname: Sukumaran
authors.affiliation: Professor, Department of Obstetrics and Gynaecology, Chettinad Hospital and Research Institute , Kancheepuram, Tamil Nadu, India .
authors.forename: Anoop
authors.initials: A
authors.lastname: Srivalsan
authors.affiliation: Professor, Department of Pathology, Chettinad Hospital and Research Institute , Kancheepuram, Tamil Nadu, India .
authors.forename: Ramesh
authors.initials: R
authors.lastname: Rao
authors.affiliation: Professor, Department of Obstetrics and Gynaecology, Chettinad Hospital and Research Institute , Kancheepuram, Tamil Nadu, India .
authors.forename: Vasantha
authors.initials: V
authors.lastname: Subbiah
keywords: Immunity; Reproductive failure; Trophoblastic growth