title: Menstrual cycle dependent fluctuations in NK and T-lymphocyte subsets from non-pregnant human endometrium.
abstract: OBJECTIVE
  To establish the relative proportions of endometrial lymphocyte subpopulations during the menstrual cycle.
  
  
  METHODS
  Lymphocytes were investigated by flow cytometry, during the early proliferative (EP), late proliferative (LP), early secretory (ES) and late secretory (LS) phases of the menstrual cycle.
  
  
  RESULTS
  Between the LP and LS phases, there was an increase in NK cells from 26.4% to 83.2% (P = 0.0017) of the CD45+ population. T cells decreased from 55.06% to 6.7% (P = 0.0017). Within the T-cell population, CD8+ cells decreased significantly from 63.0% in the LP phase to 54.2% in the LS phase (P = 0.04). In contrast, potential regulatory populations such as double negative (DN) T cells CD3+CD4-CD8- and natural T cells (NT) CD3+CD56+, increased significantly in the LS phase (P = 0.05; P = 0.03). gammadelta T cells, predominantly of the DN and NT phenotypes remained consistently low at all stages of the cycle (2.34%).
  
  
  CONCLUSIONS
  Endometrial lymphocyte fluctuations during the menstrual cycle may reflect hormonal regulation of maternal immunity, thereby promoting tolerance at the time of implantation.
authors.affiliation: Education & Research Centre, St. Vincent's University Hospital, Dublin, Ireland. cliona@vherc.ucd.ie.
authors.forename: L
authors.initials: L
authors.lastname: Flynn
authors.forename: B
authors.initials: B
authors.lastname: Byrne
authors.forename: J
authors.initials: J
authors.lastname: Carton
authors.forename: P
authors.initials: P
authors.lastname: Kelehan
authors.forename: C
authors.initials: C
authors.lastname: O'Herlihy
authors.forename: C
authors.initials: C
authors.lastname: O'Farrelly
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D010064:Embryo Implantation / Q000276:immunology; D004717:Endometrium / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D007111:Immunity, Cellular; D007694:Killer Cells, Natural; D018655:Lymphocyte Count; D008222:Lymphokines / Q000502:physiology; D008597:Menstrual Cycle / Q000276:immunology*; D008875:Middle Aged; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis; D016176:T-Lymphocyte Subsets
chemical_list: D015703:Antigens, CD; D008222:Lymphokines; D016692:Receptors, Antigen, T-Cell, gamma-delta