The Fibr-2 macrophage subset likely represents end-stage profibrotic macrophages in the silicosis lung due to waning expression of profibrotic genes coupled with increased expression of foamy macrophage markers including Spp1, Cd36, and lipid-metabolizing genes such as Lgals3 and Lrp1 (Fig. 3B). This evidence concerns the gene CD36 and silicosis.