Next, to better understand the role of iron-associated proteins in lungs during infection and why iron levels are reduced in the lungs of Fth−/− mice, we examined the expression of ferritin heavy chain (FtH), ferritin light chain (FtL), the iron exporter FPN, and heme oxygenase-1 (HO-1) by immunoblot. This evidence concerns the gene HMOX1 and infection.