SPP1 and pulmonary fibrosis: Expression of cells in this cluster was enriched for pulmonary fibrosis processes and eight genes associated with fibrosis were overexpressed in this cluster including CCL2, SPP1, FN1, CCL3, TIMP1, IL1RN, CXCL8, and CCL4. We also identified a cluster of monocyte-derived macrophages enriched for inflammatory and pulmonary fibrosis processes in which the gene expression differed between CIPF and healthy WHWTs with an enrichment for pulmonary fibrosis but also EMT and angiogenesis processes.