Using the Idiopathic Pulmonary Fibrosis (IPF) Cell Atlas, we found increased expression of phagocytosis-related genes (FCGR1A, ARPC4, ARPC5) in IPF patients across multiple datasets (Supplementary Fig. S9–S11, available at Rheumatology online). This evidence concerns the gene ARPC4 and idiopathic pulmonary fibrosis.