title: Endometrial chemokines, uterine natural killer cells and mast cells in long-term users of the levonorgestrel-releasing intrauterine system.
abstract: OBJECTIVE
  The objective was to assess endometrial chemokines in users of the levonorgestrel-releasing intrauterine system (LNG-IUS) and correlate them with leucocyte populations, uterine natural killer cells (uNK) and mast cells (MCs).
  
  
  METHODS
  Endometrium was obtained from two groups of women who had been using LNG-IUS for 3 years or more: 11 amenorrhoeic women formed the non-bleeding group and 15 women who maintained some form of cyclic bleeding comprised the bleeding group. Specific antibodies were used for the assessment of neutrophils, uNK cells and MCs. Immunohistochemistry was performed to locate the chemokines 6Ckine and interleukin-8 (IL-8).
  
  
  RESULTS
  Neutrophils were few and without differences between the two groups. uNK cells were significantly higher in the bleeding group (P < 0.0001). There was no difference between the total number of MCs and activated MCs, but there was a greater extracellular area stained for MC tryptase (P < 0.05). Chemokines 6CKine and IL-8 were abundant in the stroma and in the epithelium, and there was no difference between the groups.
  
  
  CONCLUSIONS
  We observed more uNK cells in users with bleeding and a greater extracellular area stained for MC tryptase, although there were no differences between the number of MCs and activated MCs or the chemokines 6CKine and IL-8. uNK cells and MC products may play a role in provoking breakthrough bleeding in long-term users of the LNG-IUS.
authors.affiliation: Human Reproduction Unit, Department of Obstetrics and Gynaecology, School of Medicine, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Peloggia
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Petta
authors.forename: Luis
authors.initials: L
authors.lastname: Bahamondes
authors.forename: Marilia
authors.initials: M
authors.lastname: Oliveira-Ribeiro
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.forename: Lois
authors.initials: L
authors.lastname: Salamonsen
mesh_terms: D018925:Chemokines / Q000032:analysis / Q000378:metabolism; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000009:adverse effects*; D004717:Endometrium / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D005260:Female; D006801:Humans; D007120:Immunochemistry; D007436:Intrauterine Devices, Medicated / Q000009:adverse effects*; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D016912:Levonorgestrel / Q000008:administration & dosage / Q000009:adverse effects*; D008407:Mast Cells / Q000166:cytology / Q000276:immunology; D008796:Metrorrhagia / Q000139:chemically induced / Q000276:immunology*
chemical_list: D018925:Chemokines; D003271:Contraceptive Agents, Female; D016912:Levonorgestrel