This study investigates the combinatorial patterns of histone modifications in human CD4+ T cells, focusing on 39 histone modifications. The researchers identified a significant number of patterns associated with promoters and enhancers, particularly a common module consisting of 17 modifications detected at 3,286 promoters. These modifications tend to coexist and correlate with each other at the nucleosome level. Genes associated with this module tend to have higher expression, and the addition of more modifications to this module is associated with further increased expression. The study suggests that these histone modifications may act cooperatively to prepare chromatin for transcriptional activation. The findings provide insights into the functional roles of histone modifications in gene regulation and highlight the importance of combinatorial patterns in epigenetic regulation.This study investigates the combinatorial patterns of histone modifications in human CD4+ T cells, focusing on 39 histone modifications. The researchers identified a significant number of patterns associated with promoters and enhancers, particularly a common module consisting of 17 modifications detected at 3,286 promoters. These modifications tend to coexist and correlate with each other at the nucleosome level. Genes associated with this module tend to have higher expression, and the addition of more modifications to this module is associated with further increased expression. The study suggests that these histone modifications may act cooperatively to prepare chromatin for transcriptional activation. The findings provide insights into the functional roles of histone modifications in gene regulation and highlight the importance of combinatorial patterns in epigenetic regulation.