Table 1.

NOD/SCID mice transplanted with limiting numbers of human CB repopulating cells usually contain both lymphoid and myeloid cells of human origin

Progeny combinations	Proportion of positive mice transplanted with
	Light-density cells, % (<4 × 105/mouse)	CD34+CD38− cells, % (<800/mouse)	CD34+CD38+ cells, % (<104/mouse)
M+ and/or L+	67 (12/18)	36 (20/55)	43 (7/16)
M+ only	6 (1/18)	2 (1/55)	6 (1/16)
L+ only	0 (0/18)	4 (2/55)	6 (1/16)
Expected L+ M+ (due to coincidence)	0	0.1	0.4
Observed L+ M+	61 (11/18)	32 (17/55)	31 (5/16)

M⁺, myeloid; L⁺, lymphoid. Only mice injected with doses of cells expected to contain <1 repopulating cell of any kind (based on limiting dilution analysis of the entire data set in that group) were considered in this analysis—i.e., <15% of these mice would have received >1 repopulating human cell (same experiments as shown in Table 2, but for the analysis shown here, mice were considered negative only if they contained neither lymphoid nor myeloid cells). Note also that these cell doses represent the calculated numbers expected to contain <1 such repopulating cell but, as can be seen, did not always give 37% negative mice.