Histone-modification density and enhancer class in human primary Tfh cell chromatin. The signal density of H3K4me1, H3K27Ac, H3K27me3, and background TI chromatin is plotted relative to the H3K4me1 peak. (A-C) The average signal over all enhancers in the active, intermediate, and poised enhancer classes, respectively. (D) Signal for each enhancer in the active (A), intermediate (I), and poised (P) enhancer classes. TI, total input.