title: Maternal microchimerism in human fetal tissues.
abstract: OBJECTIVE
  The aim of the present study was to analyze the presence of maternal cells in human fetal tissues in the second trimester.
  
  
  METHODS
  Tissues from 11 second-trimester fetuses terminated because of social reasons or because of malformations and/or trisomy were investigated. By cell sorting and polymerase chain reaction amplification, we studied the presence of maternal CD3+, CD19+, CD34+, and CD45+ in different fetal tissues and in placenta.
  
  
  RESULTS
  In the group of fetuses with normal karyotype and normal autopsy findings, 4 of 5 fetuses were positive for maternal microchimerism. In the group in which the fetuses were diagnosed with trisomy 21 and/or malformations, we found cells of maternal origin in 3 of 6 fetuses.
  
  
  CONCLUSIONS
  The results from this study indicate that maternal microchimerism is a common phenomenon in the second-trimester fetuses. Maternal cells of lymphoid and myeloid lineages and hematopoietic progenitors are widely distributed in the second-trimester fetuses.
authors.affiliation: Department of Obstetrics and Gynecology, the Center for Fetal Medicine, Karolinska University Hospital, Huddinge, Sweden. anna.jonsson@karolinska.se
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Jonsson
authors.forename: Mehmet
authors.initials: M
authors.lastname: Uzunel
authors.forename: Cecilia
authors.initials: C
authors.lastname: Götherström
authors.forename: Nikos
authors.initials: N
authors.lastname: Papadogiannakis
authors.forename: Magnus
authors.initials: M
authors.lastname: Westgren
mesh_terms: D046528:Chimerism; D005260:Female; D005333:Fetus / Q000166:cytology*; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second