Peripheral blood mononuclear cells (PBMC) were separated from neutrophils and red blood cells by density-gradient centrifugation. Red cells were removed from neutrophils by hypotonic lysis. Neutrophils were crosslinked using 1% formaldehyde in 10 ml PBS for 10 min at room temperature. Crosslinking was quenched by adding 1× glycine. ChIP was performed following the protocol (Cell Signaling Technologies, Inc.). DNA-sequencing was conducted using the Illumina HiSeq 2500.