MUC5B and COVID-19: Indeed, MUC5B has been proposed as a target for IPF treatment since the genetic association was first reported.102 For the causal genes with new evidence presented here, DPP9 may be particularly attractive, and inhibitors in development have been speculated to be therapeutic for pulmonary fibrosis.103 However, for treatment of COVID-19 and IPF, increasing DPP9 expression or activity seems to be the desired outcome.