According to immunofluorescence assay, the CD68+CD86+ positive (M1) cells and CD68+CD206+ positive (M2) cells were elevated following BLM induction, and especially CD68+CD206+ positive cells exhibited a dramatically dominant increase (Fig. 1C), revealing that pulmonary fibrosis triggered macrophages activation, and M2 phenotype macrophages occupied dominantly. This evidence concerns the gene MRC1 and Bloom syndrome.