ALDH^br CD34⁺, ALDH^neg CD34⁺, and ALDH^br CD34^neg cells were isolated from SSC^lo lin^neg UCB (see Figure 1). Two hundred to 1000 purified cells were cultured on STO feeder stroma in the presence of IL-3, IL-7, and IL-15, as described in “Materials and methods.” Each culture was analyzed for its expansion of CD45⁺ cells and for its relative content of lymphoid (CD56⁺) or myeloid (CD13⁺) progeny (see Figure 4). The total output of lymphoid and myeloid cells was calculated per cell that initiated the culture. Mean (±SD) and median values were determined. Statistical comparisons (P) were drawn between the lin^neg SSC^lo ALDH^br CD34⁺ and the lin^neg SSC^lo ALDH^neg CD34⁺ cell fractions using paired, 1-tailed nonparametric analyses (Wilcoxon signed rank test; n = 10).

Only 2 of 9 cultures initiated with ALDH^br CD34^neg cells could be evaluated.