SPP1hi macrophages were significantly increased in the lower lobes of patients with IPF, where fibrosis was more pronounced and expressed MERTK, LGMN, and SIGLEC10. We confirmed this finding and further applied archetypal analysis to three different subtypes: classical monocytes, profibrotic IPF macrophages, and control-enriched inflammatory macrophage subtype [20]. Here, MERTK is linked to idiopathic pulmonary fibrosis.