Cxcr2^−/− HSCs show a reduction in engraftment in primary and secondary BM transplantation assays. (A) Experimental layout for CD45.2⁺ HSCs from WT or Cxcr2^−/− mice (n = 3 per strain) transplanted into irradiated CD45.1⁺ recipients (n = 6). (B) Graph showing engraftment ability of CD45.2⁺ WT or Cxcr2^−/− HSC after 24 hours from transplant in CD45.1⁺ recipients. (C) Graph showing chimerism between CD45.2⁺ and CD45.1⁺ cells. (D) Engraftment was analyzed in the blood every 4 weeks posttransplant up to 16 weeks. Data are presented as the mean percentage of CD45.2⁺ cells within the PB. (E) After the primary recipients were sacrificed, CD45.2⁺ LSK cells were transplanted into irradiated recipients. Engraftment was analyzed in the blood every 4 weeks posttransplant up to 16 weeks. (F) Percentage of CD45.2⁺ cells was analyzed in different BM populations after 16 weeks from primary transplant, and compared between WT and Cxcr2^−/− mice. 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).