Table 3.

Comparison of the frequencies of different types of progenitors in the light-density, purified, and cultured human CB populations studied

Progenitor	Light density (per 106 cells)	CD34+CD38+ (per 103 cells)	CD34+CD38− (per 103 cells)	Cultured CD34+CD38− (per initial 103 cells)
CFC	4,000 ± 2,300	500	310  ±  130	30,000 ± 12,000
LTC-IC	52 ± 46	52	560  ±  230	2,100 ± 900
CRU	1.7 (1.3–2)	0.06 (0.04–0.08)	1.1 (0.9–1.3)	2 (1.6–2.5)
	3	2	7	6

Values shown for CFC and LTC-IC are the mean ± SEM and for CRU are the mean with the range defined by ± SE shown in parentheses. The total cell expansion in the cultures of CD34⁺CD38⁻ cells was 78 ± 33-fold.