M2 macrophages can produce IL-10, which participates in the repair of renal fibrosis tissues.[2] After the MCP-1/CCR2 axis is activated, the recruited CCR2 positive monocyte differentiate into M1 or M2 macrophages, the type of which may depend on the stage of renal fibrosis. The gene discussed is CCR2; the disease is renal fibrosis.