Macrophages represent the major pool of IL-7Rα expressing cells in patients with myocarditis.

•Myocardial inflammation is initially protective but often leads to heart failure.•Main infiltrating cells are macrophages and T cells but B cells are rarely present.•Surprisingly, macrophages but not T cells are the major IL-7Rα expressing population.•The IL-7Rα cascade is activated and might regulate trafficking of macrophages.•Consumption of IL-7 by macrophages might reduce the number of cardiac T and B cells.