Glucocorticoid-induced eosinopenia is CXCR4 dependent. (A) The CXCR4 locus in the human and rhesus genomes, highlighting the location of the GREs relative to the known transcript isoforms in each species. (B) Peripheral blood AECs and eosinophil surface expression of CXCR4 over time after a single dose of methylprednisolone (4 mg/kg IV). Results of 3 independent experiments, each in 1 unrelated adult rhesus macaque. CXCR4 surface levels are expressed as ΔMFI (MFI CXCR4 staining minus MFI isotype control). (C) Experimental design for testing the effect of CXCR4 blockade on glucocorticoid-induced eosinopenia. (D) Glucocorticoid-induced eosinopenia in the presence or absence of CXCR4 blockade. Eosinophil counts are expressed as a percentage of the BL count for each condition. Results of 3 independent experiments, each in 1 unrelated adult rhesus macaque. GC, glucocorticoid; MP, methylprednisolone; RM, rhesus macaque.