Effect of pretreatment with anti–LFA-1 on IL-1–induced mobilization of progenitor cells. Mice were pretreated with 100 μg of anti–LFA-1 or saline. The following day, 1 μg of IL-1 (n = 6 per treatment group) or 30 μg of IL-8 (n = 20 per treatment group) was administered as a single IP injection, 4 to 6 hours or 20 minutes before harvesting peripheral blood, respectively. Results are expressed as mean ± SD. **, P < .01 and *, P < .05 as compared with saline pretreated controls.