Circulating myelopoietic stem cells (CFUc): high levels in healthy pre-term infants and reduced levels in sick pre-term infants.

In healthy and diseased pre-term infants at birth, levels of circulating CFUc are 2,586 +/- 3,063 (s. d.) and 269 +/- 292 (s.d.) per 5 X 10(5) lymphoid cells, as compared to data from the literature of 5 CFUc per 5 X 10(5) mononuclear cells from the blood of adults [8]. Hypotrophic infants have the lowest concentration of CFUc in the blood, namely 78 +/- 105 (s.d.). In formerly sick infants recovering from their perinatal illness, blood CFUc levels increase to approach those from healthy infants of the same age. Our results provide evidence that blood CFUc levels in pre-term infants reflect the strong myelopoietic activity of fetal bone marrow and suggest a correlation to the clinical status of the infant.