Intriguingly, Cldn10-positive cellular masses were frequently observed in the airspace of IPF lungs and they are usually mosaic mixtures containing Cldn10-positive and negative cells with the latter being predominant (areas circled by dotted lines in Figure 2E & H; areas circled by dot-dashed lines in Figure 2I & O; area circled by dotted line in Figure 2 K; Supplemental Figure S2F, G & H). Here, CLDN10 is linked to idiopathic pulmonary fibrosis.