Circulating human cell and in vivo bioluminescence counts enable accurate assessment of total human cell engraftment. NSG-3GS (closed circles) and NSG (open circles) mice were transplanted with 0.4 to 3 × 104 luciferase-transduced CD34+ CB cells and 3 weeks later were assessed by bioluminescent imaging. (A) Representative image of transplanted mice (examples shown are NSG-3GS mice). (B) Total human cell counts in the left (L) and right (R) femurs in individually assessed NSG-3GS and NSG mice. Lines connect paired cell counts from individual mice which were significantly different (P < .05) for both strains. (C) Association between the absolute number of circulating human cells with the total number of human cells in both femurs (Pearson r = 0.64, P = .02). (D) Association between the absolute number of circulating human cells with photons emitted per second per mouse (Pearson r = 0.91, P < .001).
