FOXP3⁺Hel-FL eTregs delay disease progression in a xenogeneic GVHD murine model. NSG mice aged 8 to 12 weeks were sublethally irradiated. The next day, the mice were injected retro-orbitally with 10⁷ human PBMCs alone (n = 8), with 10⁷ human PBMCs + 5 × 10⁶ empty vector control cells (n = 6), 10⁷ human PBMCs + 5 × 10⁶ FOXP3 eTregs (n = 8), 10⁷ human PBMCs + 5 × 10⁶ FOXP3⁺HEL-FL eTregs (n = 7), or 10⁷ human PBMC + 5 × 10⁶ FOXP3⁺Hel-Δ3B eTregs (n = 7). (A) GVHD score. *P ≤ .05 compared with no eTregs based on a 1-tailed Mann-Whitney U test for each time point. (B) Kaplan-Meier curve of survival. Death was marked when the GVHD score was ≥7. The data shown are the aggregated data from 5 separate experiments that used T cells from 4 different donors. *P ≤ .05 compared with no eTregs as determined by using the log-rank test. PBS, phosphate-buffered saline.