IRF4 and chronic kidney disease: Nevertheless, based on (a) the well-documented expression of IRF4 particularly in immune cells, (b) renal hyperinflammation 5 weeks post-IRI besides tissue-infiltrating M1-primed macrophages, and (c) the occurrence of intrarenal hyperinflammation in Irf4−/− mice despite a clodronate depletion of macrophages in the acute phase of the injury, we consider that M1 macrophage–driven chronic renal inflammation causes CKD in our murine model.