title: Increased uNK Progenitor Cells in Women With Endometriosis and Infertility are Associated With Low Levels of Endometrial Stem Cell Factor.
abstract: OBJECTIVE
  Uterine natural killer (uNK) cells play a significant role in successful human pregnancy. Having previously demonstrated uNK cell progenitors in human endometrium, we hypothesized that abnormal uNK cell maturation contributes to infertility in women with endometriosis. We aimed to characterize uNK cells at different developmental stages in women with and without endometriosis and to investigate possible mechanisms to explain any differences.
  
  
  METHODS
  We characterized uNK cell development in women with and without endometriosis using flow cytometry, protein array and in vitro experiments.
  
  
  RESULTS
  We found increased proportions of uNK cells at developmental stages 1 and 2 in endometrium from women with endometriosis (n = 36; mean = 21.2%) when compared with healthy fertile women (n = 9; mean = 7.0%). Protein array analysis revealed significantly lower levels of stem cell factor (SCF) in the eutopic endometrium of women with endometriosis when compared to healthy women. Addition of SCF to endometrial progenitor cells in vitro restored uNK cell maturation.
  
  
  CONCLUSIONS
  We have shown that women with endometriosis have low levels of endometrial SCF, which we hypothesize contributes to abnormal maturation of local uNK cell populations. This defect may also compromise embryo implantation and hence contribute to endometriosis-associated infertility. SCF replacement may be a new therapeutic approach.
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Uma
authors.initials: U
authors.lastname: Thiruchelvam
authors.affiliation: Merrion Fertility Clinic, National Maternity Hospital, Dublin 2, Ireland.|UCD School of Medicine and Medical Science, Dublin 2, Ireland.
authors.forename: Mary
authors.initials: M
authors.lastname: Wingfield
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.|School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Cliona
authors.initials: C
authors.lastname: O'Farrelly
mesh_terms: D000328:Adult; D004715:Endometriosis / Q000276:immunology* / Q000473:pathology; D004717:Endometrium / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000276:immunology* / Q000473:pathology; D007694:Killer Cells, Natural / Q000276:immunology* / Q000473:pathology; D054503:Lymphoid Progenitor Cells / Q000276:immunology* / Q000473:pathology; D011247:Pregnancy; D019089:Stem Cell Factor / Q000276:immunology*
chemical_list: D019089:Stem Cell Factor
keywords: Endometriosis; NK development; Uterine natural killer cell