Addition of extra Foxp3^GFP+ Treg results in a reconstitution delay of donor-BM–derived Tregs. (A-B) Seven weeks post-BMT, blood and spleen cells were isolated and stained with congenic markers to distinguish extra injected Foxp3^GFP+ Treg (gray bar), host (black bar), and donor (white bar) CD4⁺ T cells (TCRβ⁺CD4⁺) and Tregs (TCRβ⁺CD4⁺CD25⁺Foxp3⁺). (A) CD4⁺ T-cell reconstitution in blood (left) and spleen (right). (B) Treg reconstitution in blood (left) and spleen (right). All figures show absolute numbers ± SEM error bars. PGIA, N = 3; PGIA+BMT, N = 4; PGIA+BMT+250,000 Tregs, N = 5; and PGIA+BMT+500,000 Tregs, N = 5. *P < .05 for donor cell compartment.