Objective: This study aimed to explore the differentially expressed genes (DEGs) of pulmonary macrophages in human idiopathic pulmonary fibrosis (IPF) by bioinformatics, and elaborate on IPF on the gene level. Methods: The gene expression profile GSE49072 was downloaded from the gene expression omnibus (GEO) database. Genes of alveolar macrophages between normal volunteers and patients diagnosed as IPF were analyzed by GEO2R tools. Gene ontology (GO) and pathway enrichment analyses of genes were performed in the database for annotation, visualization and integrated discovery (DAVID) database, followed by functional annotation and protein-protein interaction (PPI) network construction in String website. Finally, the results were analyzed in a comprehensive way. Results: A total of 551 DEGs, including 205 down-regulated and 346 up-regulated were identified. The expression of 209875_s_at (secreted phosphoprotein 1, SPP1) and 214146_s_at (pro-platelet basic protein, PPBP) genes are the most significant in upregulated genes. DEGs in the MAPK（mitogen-activated protein kinase） signaling pathway and chemokine signaling pathway play important roles in the development of IPF. Conclusions: The up-regulation of genes such as SPP1 and PPBP affect the secretion of alveolar macrophages, thereby speeding up the process of fibrosis.
Keywords: Alveolar macrophages; IPF; bioinformatics; fibrosis; genes.