Based on the previously established association of pro-fibrotic SPP1+ macrophages with cirrhotic liver and lungs from idiopathic pulmonary fibrosis (IPF) patients (Morse et al., 2019; Ramachandran et al., 2019), we hypothesised that this macrophage population can be detected in other human tissues and can associate with broader fibrotic disease state. Here, SPP1 is linked to pulmonary fibrosis.