Circulating stem cells in extremely preterm neonates

Acta Paediatr. 2007 Apr;96(4):521-5. doi: 10.1111/j.1651-2227.2007.00194.x.


Aim: 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Factors
  • Antigens, CD34 / physiology*
  • Blood Cell Count
  • Flow Cytometry
  • Follow-Up Studies
  • Hematopoietic Stem Cells*
  • Humans
  • Infant, Newborn
  • Infant, Premature
  • Observation
  • Prospective Studies
  • Recovery of Function / physiology
  • Respiratory Distress Syndrome, Newborn / blood*
  • Respiratory Distress Syndrome, Newborn / complications
  • Respiratory Function Tests


  • Antigens, CD34