title: Lymphocytes and perforin expression in endometrium during the menstrual cycle.
abstract: OBJECTIVE
  To study the lymphocytes, perforin protein and mRNA expression in endometrium of different phases in the menstrual cycle and to explore the regularity and role of the lymphocytes and perforin in the reproductive system.
  
  
  METHODS
  Immunohistochemical and in situ hybridization techniques were employed to demonstrate the population, phenotype and mediator (perforin) of lymphocytes in the proliferative and secretory endometrium.
  
  
  RESULTS
  In different phases of the endometrium, there were very few CD3+ typical T lymphocytes, CD4+ helper lymphocytes and CD8+ suppressor/cytotoxic T lymphocytes, while CD56+ lymphocyte (also named NK-like cell) were abundant. CD56+ lymphocytes were absent in postmenopausal endometrium. A double immunohistochemical labelling method demonstrated the co-expression of perforin protein and CD56 antigen of cells in different phases of the endometrium. Quantitative analysis of CD56+ lymphocytes and perforin-positive cells increased in number from the proliferative to the secretory endometrium (P < 0.05). In situ hybridization analysis showed that perforin mRNA positive cells formed islands in proliferative endometrial stroma, but were scattered in secretory endometrium. There was difference between perforin gene expression and protein expression in the proliferative endometrium.
  
  
  CONCLUSIONS
  Lymphocytes and perforin expression in the endometrium at different phases of the menstrual cycle are specific and may play an important role in the reproductive system. They may exert a positive influence on embryo implantation and be involved in endometrial stroma breakdown during menstruation.
authors.affiliation: Department of Obstetrics and Gynecology, Third Clinical Medical School, Beijing Medical University, Beijing 100083, China.
authors.forename: X
authors.initials: X
authors.lastname: Tian
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Zhang
mesh_terms: D004717:Endometrium / Q000166:cytology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000235:genetics; D008597:Menstrual Cycle / Q000378:metabolism; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000502:physiology*
chemical_list: D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger; D054353:Perforin