Immunophenotype after cytoreduction and neonatal BMT. All mice were age-matched (200-240 days) in the experimental arms: ADA-deficient mice (no cytoreduction, n = 3; 100 cGy, n = 7; 200 cGy, n = 2; and 400 cGy, n = 1; busulfan, n = 6) after 240 days. (A) Absolute numbers of thymocytes and splenocytes. Data are means plus or minus SEM. Significant dose-response in splenocytes (P < .001). (B) Absolute numbers in each thymocyte subpopulation (CD4⁺, CD8⁺, double-positive (DP): CD4⁺, CD8⁺, double-negative (DN): CD4⁻, CD8⁻) were calculated by multiplying the total numbers of cells collected from the thymus by the percentage of cells in each subpopulation. (C) Absolute numbers in each splenocyte subpopulation (CD4⁺, CD8⁺, CD19⁺) were calculated by multiplying the total numbers of cells collected from the spleen by the percentage of cells in each subpopulation. Significant dose-response in CD19⁺ (P < .001).