Engraftment of human CD45⁺ lymphoid cells in the BM compartment and thymic grafts of CB/Thy-NOD/SCID mice. Each bar represents the proportion (a and b) or absolute numbers (c and d) of human CD45⁺ cells detected by FACS analysis of cell suspensions from the BM (white bars) or thymic grafts (gray bars) of individual mice at 4 months (a and c) and 6 months (b and d) post-CB reconstitution. Data in (a and c) were generated in 4 different experiments and data in (b and d) in 6 different experiments using different CB donors in each experiment.