Cxcr2^−/− mice show an expansion of the stem cell compartment. (A) BM (left) and spleen (right) from WT mice (n = 6) or Cxcr2^−/− mice (n = 6) were harvested and assessed for total cellularity. (B) Numbers of LSK cells for BM (left) and spleen (right) from WT mice or Cxcr2^−/− mice. (C) Numbers of HSC, MPP, HPC-1, and HPC-2 in the BM (left) and spleen (right) from WT mice or Cxcr2^−/− mice are shown. (D) Numbers for BM (left) and spleen (right) erythroid, granulocytic, and B-cell populations from WT and Cxcr2^−/− mice are shown. (E) Numbers for T-cell populations in the WT and Cxcr2^−/− spleen identified with CD4 and CD8 markers are shown. (F) Numbers for T-lineage populations in the WT and Cxcr2^−/− thymi identified with CD4 and CD8 markers are shown. Statistical analysis was performed using an unpaired two-tailed Student t test. All error bars indicate SEM of the mean (*P < .05; **P < .01; ***P < .001) (n = 6).