Role of CXCR2 and CXCR4 in KC-induced neutrophilia. (a) WT mice were pretreated for 1 h s.c. with plerixafor before i.v. treatment of KC at different doses. Number of circulating neutrophils detected 2 h after KC administration (n = 5 per group per dose). The control group consists of mice treated i.v. with KC only at specified doses. A representative set of data were shown from two independent experiments. All data are shown as mean ± SEM. (b) The mean traveling distance of neutrophils from the BM parenchyma to the sinusoids before egression. This was measured in LysM-GFP mice pretreated for 1 h with s.c. PBS or plerixafor after i.v. KC administration (500 ng per mouse). Graph shows dataset from a representative mouse (n = 3 per group). See also Video 6. All data are shown as mean ± SEM. A Student’s two-tailed unpaired t test was performed. *, P < 0.05.