Plasma CXCL12 and S1P concentrations decrease after AMD3100, G-CSF, or G-CSF plus chemotherapy–mediated mobilization. (A) Mice were treated twice daily with 250 mg/kg of G-CSF for 5 days or 10 mg/kg of AMD3100 1 hour before being killed. Plasma was collected and analyzed for S1P levels by ELISA. The mean and SD of data obtained from 6 mice is shown. *P < .05. (B-D) Donors for allogeneic transplantations were mobilized with G-CSF, whereas patients scheduled for autologous transplants were mobilized with G-CSF with or without chemotherapy. Premobilization samples (Pre) were collected before the commencement of the mobilization protocol. Postmobilization samples for G-CSF were collected just before the first leukapheresis. The concentration of S1P (B) and CXCL12 (C) is shown. Each dot represents data from a single patient and the horizontal line indicates the mean of the cohort. Connected dots indicate samples from the same patient. (D) The level of S1P (left panel) and CXCL12 (right panel) in autograft patients who mobilized well (Good, > 50 CD34⁺ cells/μL) or relatively poorly (Poor, < 50 CD34⁺ cells/μL). The mean and SD of the all samples assessed is shown for samples collected before (Pre) the commencement of the mobilization procedure or on the day of the first collection (Post). *P < .05. (E) Plasma S1P concentrations in 14 donors mobilized with AMD3100 collected at the indicated time points. The data for each patient were normalized to baseline S1P concentrations and the mean and SD of data from all 14 patients is shown.