title: Transfer of fetal cells with multilineage potential to maternal tissue.
abstract: BACKGROUND
  During pregnancy, fetal CD34+ cells enter the maternal circulation, persist for decades, and create a state of physiologic microchimerism. Many studies have confirmed the residual presence of fetal cells in maternal blood and tissues following pregnancy. Fetal cells may respond to maternal injury by developing multilineage capacity in maternal organs.
  
  
  OBJECTIVE
  To verify that fetal microchimeric cells express markers of epithelial, leukocyte, and hepatocyte differentiation within maternal organs.
  
  
  METHODS
  Archived paraffin-embedded tissue section specimens from 10 women who had male offspring and were previously found to have high numbers of microchimeric cells, and 11 control women who had no prior male pregnancies. Male cells were identified by fluorescence in situ hybridization, using X and Y chromosome-specific probes, followed by histologic and immunochemical studies using anticytokeratin (AE1/AE3) as a marker of epithelial cells, anti-CD45 as a leukocyte marker, and heppar-1 as a hepatocyte marker.
  
  
  METHODS
  Percentage of microchimeric cells expressing nonhematopoietic markers.
  
  
  RESULTS
  A total of 701 male (XY+) microchimeric cells were identified (mean [SD], 227 [128] XY+ cells per million maternal cells). In maternal epithelial tissues (thyroid, cervix, intestine, and gallbladder), 14% to 60% of XY+ cells expressed cytokeratin. Conversely, in hematopoietic tissues, such as lymph nodes and spleen, 90% of XY+ cells expressed CD45. In 1 liver sample, 4% of XY+ cells expressed heppar-1. Histologic and immunochemical evidence of differentiation, as assessed by independent observers, was highly concordant (kappa = 0.72).
  
  
  CONCLUSIONS
  The detection of microchimeric male cells, bearing epithelial, leukocyte, or hepatocyte markers, in a variety of maternal tissue specimens suggests the presence of fetal cells that may have multilineage capacity.
authors.affiliation: Department of Pediatrics, Tufts-New England Medical Center, Boston, Mass 02111, USA.
authors.forename: Kiarash
authors.initials: K
authors.lastname: Khosrotehrani
authors.forename: Kirby L
authors.initials: KL
authors.lastname: Johnson
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Cha
authors.forename: Robert N
authors.initials: RN
authors.lastname: Salomon
authors.forename: Diana W
authors.initials: DW
authors.lastname: Bianchi
mesh_terms: D000328:Adult; D000368:Aged; D001457:Anion Exchange Protein 1, Erythrocyte; D002454:Cell Differentiation; D002678:Chimera / Q000235:genetics*; D004847:Epithelial Cells / Q000166:cytology*; D005260:Female; D005333:Fetus / Q000166:cytology*; D005704:Gallbladder / Q000166:cytology; D022781:Hepatocytes / Q000166:cytology*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007422:Intestines / Q000166:cytology; D017493:Leukocyte Common Antigens; D007962:Leukocytes / Q000166:cytology*; D008099:Liver / Q000166:cytology; D008198:Lymph Nodes / Q000166:cytology; D008297:Male; D008431:Maternal-Fetal Exchange / Q000235:genetics*; D008875:Middle Aged; D010641:Phenotype; D011247:Pregnancy; D013154:Spleen / Q000166:cytology; D013234:Stem Cells / Q000166:cytology*; D013961:Thyroid Gland / Q000166:cytology
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D017493:Leukocyte Common Antigens