GPX3 and sarcoidosis: As we had observed upregulation of GPX3 both during the inflammatory (day 7) and fibrotic (day 14) phase of bleomycin-induced lung fibrosis35, 46 (Fig. 1B,C,E), upregulation in IPF (Fig. 4), as well as high levels in BALF from ILDs with a strong inflammatory component such as HP and sarcoidosis (cf. Fig. 3A), we investigated whether GPX3 is upregulated by the proinflammatory cytokine TNF-α or the profibrotic cytokine TGF-β1 in phBEC and phLF.