Exacerbated B-cell phenotype in IL-7Rα compared with IL-7 ligand-deficient mice. (A) Mean (SD) tibia and spleen cellularities. (B) Fluorescence-activated cell sorting (FACS) profiles and mean (SD) numbers of pro-B, pre-B, and imm-B cells in BM and (C) mean (SD) numbers of B220IgM⁺ cells in spleens of 3-week-old WT (n = 4), Il7^−/− (n = 8), and Il7r^−/− (n = 8) mice (each from 2 litters). Numbers in FACS profiles show the mean percentages of cells in quadrants or gates as indicated (*P < .05, **P < .01, ***P < .001).