title: Circulating stem cells in extremely preterm neonates.
abstract: OBJECTIVE
  To measure circulating CD34+ cell levels in premature neonates and to correlate the initial CD34+ counts with measures of pulmonary function and neonatal morbidity.
  
  
  METHODS
  CD34+ cell counts were measured in the peripheral blood of preterm neonates (gestational ages 24-32 weeks) ventilated for respiratory disease at <48 h of life, and at the start of the 2nd, 3rd and 4th weeks of life. Data pertaining to neonatal demographics and short-term outcomes were collected. Pulmonary function tests were performed to coincide with CD34+ sampling.
  
  
  RESULTS
  Thirty preterm neonates with median gestational age of 24 weeks and birth weight of 641 g were analysed. A mean of 99.4 CD34+ cells per microliter was observed in the 1st week of life with a decline to 54.4 cells per microliter by the 4th week. An inverse correlation between initial CD34+ count and gestational age (p=0.01) was observed. No significant correlations were observed with measures of pulmonary function or neonatal morbidities.
  
  
  CONCLUSIONS
  Extremely premature neonates have remarkably high levels of CD34+ cells in their peripheral blood at birth. Umbilical cord blood from this population may potentially provide an abundant source of hematopoietic stem and progenitor cells for therapeutic purposes.
authors: Department of Pediatrics, Division of Perinatal Medicine, Yale University School of Medicine, New Haven, CT 06520-8064, USA. matthew.bizzarro@yale.edu
authors: Matthew J
authors: MJ
authors: Bizzarro
authors: Vineet
authors: V
authors: Bhandari
authors: Diane S
authors: DS
authors: Krause
authors: Brian R
authors: BR
authors: Smith
authors: Ian
authors: I
authors: Gross
mesh_terms: D000367:Age Factors; D018952:Antigens, CD34 / Q000502:physiology*; D001772:Blood Cell Count; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006412:Hematopoietic Stem Cells; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019370:Observation; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood* / Q000150:complications; D012129:Respiratory Function Tests
chemical_list: D018952:Antigens, CD34