Comparison of the total number of human cells of the phenotypes shown found to be present in the tibias and femurs of mice transplanted with cells obtained from the marrow of primary mice transplanted with human cord blood cells and administered a 2-week course of SF, IL-3, GM-CSF, and Ep (solid symbols) or not (open symbols). Data pooled from the four experiments described in Table 1. Each symbol denotes an individual secondary mouse. The corresponding % human (CD45/71⁺) cell repopulation values for the marrows of these secondary mice that contained greater than 0.1% human cells ranged from 0.3% to 12%.