Greater proportion of modified peripheral blood cells 20 weeks after transplantation is induced by tEpoR. (A) Mean percentages, standard errors, and individual values of eGFP-positive RBCs and WBCs. HCs were transduced by RV (1), RV/Y1 (2), RV/Y1-2 (3), or RV/Y1-8 (4) retroviral vectors. (B) Mean plasma Epo levels and standard errors measured in the same mice. *P < .05 compared with groups 1 and 4.