title: Fetal thymus size in human pregnancies reveals inverse association with regulatory T cell frequencies in cord blood.
abstract: OBJECTIVE
  To determine fetal thymus growth and its relationship with fetal weight and cord blood T-regulatory cells in a prospective study. Assessment of fetal immune organs by ultrasound could provide a screening approach to identify fetuses at risk of impaired postnatal immunity.
  
  
  METHODS
  Thymus size was measured with four ultrasound techniques. The approaches with lowest coefficient of variation (thymus transverse diameter, 3 vessel edge) were used to longitudinally assess fetal and thymus growth in 137 cases at four time points between a gestational age (GA) of 13 and 37 weeks. Cord blood at birth was analyzed by flow-cytometry to evaluate the frequency of regulatory T (Treg) cells.
  
  
  CONCLUSIONS
  Fetal thymus growth is significantly correlated with fetal weight (GA 23-25 weeks r=0.40, p<0.01; GA 28-30 weeks r=0.21, p=0.04, GA 35-37 weeks r=0.56, p<0.01). We observed an inverse correlation between fetal thymus size at GA 23-25 weeks and cord blood Treg cells (r=0.37, p=0.01). Thymus growth occurs in a linear fashion throughout pregnancy and can be reliably measured using ultrasound. Our findings of an inverse correlation between thymus growth and Treg cells in cord blood suggests a link between fetal growth, thymus development and immune-status at birth.
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany. Electronic address: a.diemert@uke.de.
authors: Anke
authors: A
authors: Diemert
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany.
authors: Isabel
authors: I
authors: Hartwig
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany.
authors: Mirja
authors: M
authors: Pagenkemper
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany.
authors: Ryoko
authors: R
authors: Mehnert
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany.
authors: Gudula
authors: G
authors: Hansen
authors: Department of Immunology, University Medical Center Hamburg, Germany.
authors: Eva
authors: E
authors: Tolosa
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany.
authors: Kurt
authors: K
authors: Hecher
authors: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg, Germany.
authors: Petra
authors: P
authors: Arck
mesh_terms: D000328:Adult; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D020567:Fetal Weight / Q000276:immunology*; D005333:Fetus / Q000166:cytology / Q000276:immunology; D006801:Humans; D009929:Organ Size; D011247:Pregnancy / Q000276:immunology*; D011446:Prospective Studies; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology; D013950:Thymus Gland / Q000254:growth & development / Q000276:immunology
keywords: Fetal immune system; Fetal thymus; Fetal ultrasound; T-cells