In the NADPH oxidase knockout mice that lack the gp91phox (Nox2) subunit of a NOX enzymatic complex and are deficient in ROS production, lung fibrosis induced by SWCNTs or MWCNTs was remarkably attenuated, compared with the wild-type control mice [122, 125, 175, 176]. Here, CYBB is linked to pulmonary fibrosis.