Cell-subset–specific DNA methylation profiles of purified primary human leukocytes. (A-B) Genome-wide DNA methylation profiles of purified leukocyte cell subsets using the Illumina Infinium HumanMethylation450 BeadChip. The DNA methylation status of each CpG site was classified as “unmethylated,” “partially methylated,” or “methylated” and the number of probes of each status plotted per cell type. (A) Genomic location of individual sites in relation to TSSs. Location of probes referred to as within TSSs, 200 bp upstream or downstream from the TSSs, and far upstream and downstream (200-1500 bp from TSSs). (B) Distribution of sites with regard to their position relative to CGIs. CpG shores were defined as the 2-kb regions flanking CGIs, and the shelves as 2-kb regions extending from the shores. Probes located further away from CGIs are defined as being in open sea.