G-CSF–induced splenomegaly and LSK cell mobilization is enhanced in FVIIIKO mice. (A) Macroscopic view of selected spleens of FVIIIKO and C57BL/6 mice either with or without 7 days of G-CSF treatment. (B) Average spleen weight (mg) of C57BL/6 (left) and FVIIIKO (right) mice in the presence or absence of G-CSF treatment (2-way ANOVA, P < .01). (C) Number of CFUs before and after G-CSF treatment in the spleen of FVIIIKO (white) or C57BL/6 mice (black). (D) Number of LSK cells in PB of control and G-CSF–treated splenectomized FVIIIKO and C57BL/6 mice. Error bars are means ± SD.