C1QA and idiopathic pulmonary fibrosis: Macrophages play an important regulatory role in IPF development, and we found that up-regulated genes in macrophages, including C1QA, C1QB [44], and APOC1 [45], may be associated with immune regulation and inflammatory response, while down-regulated genes, including MGP [46], SCGB3A1 [47], and SFPT [48] may be involved in abnormalities of fibrosis and tissue repair.