title: Immunophenotypic characterization of human fetal liver hematopoietic stem cells during the midtrimester of gestation.
abstract: OBJECTIVE
  Our purpose was to define the extent to which gestational age influences the number of fetal liver cells that coexpress phenotypic markers associated with hematopoietic stem cells and major histocompatibility antigens.
  
  
  METHODS
  Fetal liver cells from abortuses of 9 to 24 weeks of gestation were studied (n = 61). Low-density nucleated liver cells were isolated on a discontinuous density gradient and subsequently incubated with antibodies that recognize markers of hematopoietic stem cells (i.e., CD33, CD34, CDw90, CD117, and CD123). Human leukocyte antigen class I (A, B, C) and class II (DR) antigens were also determined on these cells. Each sample was analyzed by immunocytochemistry and flow cytometry. Analysis of variance was used for statistical analysis.
  
  
  RESULTS
  Of the markers measured, only the percentage of CD123-positive cells increased significantly with gestational age (p < 0.01). The percentage of triple-positive cells (CD34+, CD117+, and CD123+) increased with age but did not reach significance (p = 0.05). Human leukocyte A, B, and C antigens were expressed on all nucleated cells from 9 to 24 weeks of gestation. Human leukocyte DR antigen, however, was expressed only on 50% of these cells. The percentage of cells that expressed both hematopoietic stem cell markers and DR antigen did not vary with gestational age.
  
  
  CONCLUSIONS
  From 9 to 24 weeks of gestation the number of human fetal liver hematopoietic stem cells that coexpress major histocompatibility antigens increases with advancing gestational age, largely because the percentage of these cells remains constant while the liver mass increases.
authors.affiliation: Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Gilles
authors.forename: M Y
authors.initials: MY
authors.lastname: Divon
authors.forename: E
authors.initials: E
authors.lastname: Bentolila
authors.forename: O D
authors.initials: OD
authors.lastname: Rotenberg
authors.forename: D F
authors.initials: DF
authors.lastname: Gebhard
authors.forename: W K
authors.initials: WK
authors.lastname: Rashbaum
authors.forename: W D
authors.initials: WD
authors.lastname: Lyman
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D005865:Gestational Age; D006680:HLA Antigens / Q000032:analysis*; D015234:HLA-A Antigens / Q000032:analysis; D015235:HLA-B Antigens / Q000032:analysis; D015236:HLA-C Antigens / Q000032:analysis; D006684:HLA-DR Antigens / Q000032:analysis; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008099:Liver / Q000166:cytology* / Q000196:embryology* / Q000276:immunology; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D063268:Sialic Acid Binding Ig-like Lectin 3
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D006680:HLA Antigens; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens; D006684:HLA-DR Antigens; D007074:Immunoglobulin G; D063268:Sialic Acid Binding Ig-like Lectin 3; D019009:Proto-Oncogene Proteins c-kit