Long-term engraftment of donor cells, correction of systemic detoxification and lung alterations after neonatal treatment. (A) The percentage of donor cells was evaluated in peripheral blood–nucleated cells from ADA^–/– mice treated with fresh (ADA^–/– BMT fresh; n = 8) or cultured BM (ADA^–/– BMT cultured; n = 5), and GT (ADA^–/– GT; n = 5) at the indicated time by quantitative PCR for donor cells. ND indicates not done. (B) ADA activity (top) and dAXP levels (bottom) were measured in RBCsof ADA^–/– mice treated with fresh (ADA^–/– BMT fresh) or ex vivo cultured BM (ADA^–/– BMT cultured), as well as with GT (ADA^–/– GT) at 7, 13, and 17 weeks after treatment. Values obtained from untreated age-matched ADA^+/+ mice (^+/+; n = 9) and 18-day-old ADA^–/– mice (^–/–; n = 10) are also shown. ND indicates not done. Values in panels A and B are shown as mean ± SD. (C) Histopathologic analysis (×5 magnification) of H&E-stained sections from lungs of untreated ADA^+/+ (top left panel) and ADA^–/– (top right panel), and ADA^–/– mice given transplants of LV-transduced BM cells (^–/– GT; bottom left panel) or ADA^+/+ BM cells (^–/– BMT; bottom right panel). Tissues from ADA^+/+, GT, and BMT mice were collected at 6 months after treatment, and from untreated ADA^–/– mice at 18 days after birth.