CD109 and idiopathic pulmonary fibrosis: In the lungs of patients with IPF, CD109 is prominently expressed in basal cells, as well as in endothelial cells and macrophages although, under normal conditions, CD109 is mainly expressed in conventional dendritic cells (cDCs) (Lung cell Atlas (https://asthma.cellgeni.sanger.ac.uk), and IPF Cell Atlas (http://www.ipfcellatlas.com)).