However, a recent report has shown that bleomycin treatment in C/EBPζ−/− mice results in lung ECM deposition associated with an increased number of Arg1-positive macrophages (M2) that activate lung fibroblasts, indicating that C/EBPζ can inhibit M2 polarization to alleviate lung fibrosis [97]. Here, ARG1 is linked to pulmonary fibrosis.